Inventory and seismic assessment of earthquake-vulnerable masonry and concrete buildings
Kevin Quinn Walsh, MS, PE (US)
A thesis submitted in partial fulfilment of the requirements for the degree of Doctor of Philosophy
Supervised by Jason Ingham, PhD, MBA and Richard Henry, PhD
The University of Auckland Department of Civil and Environmental Engineering New Zealand
November 2015
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Abstract Following the 2010–2011 Canterbury earthquakes, a renewed focus has been directed across New Zealand to the hazard posed by the country‘s earthquake-vulnerable buildings, namely unreinforced masonry (URM) and reinforced concrete (RC) buildings with potentially nonductile components that have historically performed poorly in large earthquakes. The research reported herein was pursued with the intention of addressing several recommendations made by the Canterbury Earthquakes Royal Commission of Inquiry which were classified into the following general categories:
Identification and provisional vulnerability assessment of URM and RC buildings and building components;
Testing, assessment, and retrofitting of URM walls loaded out-of-plane, with a particular focus on highly vulnerable URM cavity walls;
Testing and assessment of RC frame components, especially those with presumably non-ductile reinforcement detailing;
Portfolio management considering risks, regulations, and potential costs for a portfolio that includes several potentially earthquake-vulnerable buildings; and
Ongoing investigations and proposed research needs.
While the findings from the reported research have implications for seismic assessments of buildings across New Zealand and elsewhere, an emphasis was placed on Auckland given this research program‘s partnership with the Auckland Council, the Auckland region accounting for about a third each of the country‘s population and economic production, and the number and variety of buildings within the Auckland building stock. An additional evaluation of a historic building stock was carried out for select buildings located in Hawke‘s Bay, and additional experimental testing was carried out for select buildings located in Hawke‘s Bay and Christchurch.
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Acknowledgements First, foremost, and above all else… to my wife Megan without whom I could not have even fathomed pursuing this venture, no less completed it. Special thanks as well to Jason, Dmytro, Rick, Nicola, Patrick, Marta, Reza, and the many other friends and colleagues at the University of Auckland and the Auckland Council who supported these research efforts as well as contributed to my New Zealand cultural experience.
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Co-Authorship Form
Graduate Centre ClockTower – East Wing 22 Princes Street, Auckland Phone: +64 9 373 7599 ext 81321 Fax: +64 9 373 7610 Email:
[email protected] www.postgrad.auckland.ac.nz
This form is to accompany the submission of any PhD that contains research reported in published or unpublished co-authored work. Please include one copy of this form for each co-authored work. Completed forms should be included in all copies of your thesis submitted for examination and library deposit (including digital deposit), following your thesis Acknowledgements.
Please indicate the chapter/section/pages of this thesis that are extracted from a co-authored work and give the title and publication details or details of submission of the co-authored work. Chapter 2: Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock [earlier version of work submitted to Journal of Performance of Constructed Facilities in Aug 2015] Nature of contribution by PhD candidate
Wrote all text and performed all extrapolations and technical analyses charted in the article
Extent of contribution by PhD candidate (%)
90%
CO-AUTHORS Name
Nature of Contribution
Patrick Cummuskey
Commissioned engineers who performed most field assessments considered in article
Reza Jafarzadeh
Provided internal review of article and technical support regarding extrapolations
Jason Ingham
Provided internal review of article
Certification by Co-Authors The undersigned hereby certify that: the above statement correctly reflects the nature and extent of the PhD candidate’s contribution to this work, and the nature of the contribution of each of the co-authors; and in cases where the PhD candidate was the lead author of the work that the candidate wrote the text. Name
Signature
Date
Patrick Cummuskey
25/08/2015
Reza Jafarzadeh
19/08/2015
Jason Ingham
25/08/2015 Click here Click here Click here
Last updated: 25 March 2013
Co-Authorship Form
Graduate Centre ClockTower – East Wing 22 Princes Street, Auckland Phone: +64 9 373 7599 ext 81321 Fax: +64 9 373 7610 Email:
[email protected] www.postgrad.auckland.ac.nz
This form is to accompany the submission of any PhD that contains research reported in published or unpublished co-authored work. Please include one copy of this form for each co-authored work. Completed forms should be included in all copies of your thesis submitted for examination and library deposit (including digital deposit), following your thesis Acknowledgements.
Please indicate the chapter/section/pages of this thesis that are extracted from a co-authored work and give the title and publication details or details of submission of the co-authored work. Appendix E: Displacement-based RC column assessment for a case study interwar building [earlier version of work submitted to Sesoc Journal in Jul 2015] Nature of contribution by PhD candidate Extent of contribution by PhD candidate (%)
Assisted in field inspection, wrote all text, and performed most technical analyses described in the article 90
CO-AUTHORS Name
Nature of Contribution
Dmytro Dizhur
Provided technical oversight on analytical techniques and internal review of article
Peter Liu
QC of NLTHA and internal review of article
Mostafa Masoudi
QC of column pushover analysis and internal review of article
Jason Ingham
Provided technical oversight on analytical techniques and internal review of article
Certification by Co-Authors The undersigned hereby certify that: the above statement correctly reflects the nature and extent of the PhD candidate’s contribution to this work, and the nature of the contribution of each of the co-authors; and in cases where the PhD candidate was the lead author of the work that the candidate wrote the text. Name
Signature
Date
Dmytro Dizhur
28/07/2015
Peter Liu
3/08/2015
Mostafa Masoudi
28/07/2015
Jason Ingham
28/07/2015
Click here
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Last updated: 25 March 2013
Table of contents Abstract .................................................................................................................................................. iii Acknowledgements................................................................................................................................. v List of figures .........................................................................................................................................xiv List of tables ........................................................................................................................................ xviii Chapter 1. Introduction ........................................................................................................................... 1 1.1. Research motivation and dissemination...................................................................................... 4 1.2. Research objectives and scope .................................................................................................... 5 1.3. Thesis format and chapter content ............................................................................................. 6 1.3.1. Chapter 2. Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock .................................................................. 7 1.3.2. Chapter 3. Geometric characterisation and out-of-plane seismic stability of low-rise unreinforced brick masonry buildings in Auckland, New Zealand.................................................. 7 1.3.3. Chapter 4. Seismic considerations for the Art Deco interwar reinforced concrete buildings of Napier, New Zealand .................................................................................................................. 8 1.3.4. Chapter 5. In situ out-of-plane testing of unreinforced masonry cavity walls in as-built and improved conditions ....................................................................................................................... 9 1.3.5. Chapter 6. Ancillary considerations for assessing unreinforced masonry walls for out-ofplane performance........................................................................................................................ 10 1.3.6. Chapter 7. Testing of RC frames extracted from a building damaged during the Canterbury earthquakes ............................................................................................................... 11 1.3.7. Chapter 8. Seismic risk management of a large public facilities portfolio: a New Zealand case study...................................................................................................................................... 11 1.3.8. Appendix E. Displacement-based RC column assessment for a case study interwar building ......................................................................................................................................... 12 1.4. References ................................................................................................................................. 13 Chapter 2. Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock ................................................................................................ 15 2.1. Introduction ............................................................................................................................... 15 2.2. Research motivation .................................................................................................................. 16 2.3. Rapid seismic building evaluations ............................................................................................ 17 2.4. Building taxonomies and data considered ................................................................................. 18 2.4.1. Primary lateral load resisting system (LLRS) construction type categories ........................ 20 2.4.2. Number of storeys .............................................................................................................. 24 2.4.3. Time period of construction, reconstruction, or retrofit .................................................... 25 vi
2.4.4. Typological groupings by structure type, number of storeys, and time period of construction .................................................................................................................................. 27 2.4.5. Occupancy / usage type and importance level ................................................................... 27 2.5. Building and component vulnerabilities .................................................................................... 30 2.6. RC moment resisting frames with potentially non-ductile columns ......................................... 32 2.6.1. Structural footprint ratio .................................................................................................... 33 2.6.2. RC column pushover capacity assessment ......................................................................... 34 2.7. Summary and recommendations............................................................................................... 35 2.8. Further considerations ............................................................................................................... 37 2.9. Acknowledgements.................................................................................................................... 38 2.10. References ............................................................................................................................... 38 Chapter 3. Geometric characterisation and out-of-plane seismic stability of low-rise unreinforced brick masonry buildings in Auckland, New Zealand ............................................................................. 43 3.1. Introduction ............................................................................................................................... 43 3.2. Inventory of URM buildings in Auckland ................................................................................... 45 3.2.1. Primary lateral load resisting material and system ............................................................ 46 3.2.2. Number of storeys .............................................................................................................. 47 3.2.3. Year of construction or retrofit ........................................................................................... 48 3.2.4. Typological groupings by structure type, number of storeys and year of construction..... 49 3.2.5. Occupancy / usage type and importance level ................................................................... 49 3.3. Out-of-plane seismic assessment of exterior URBM walls ........................................................ 51 3.3.1. URBM typologies................................................................................................................. 53 3.3.2. Exterior wall materials and vertical geometry .................................................................... 55 3.3.3. Vertical exterior wall conditions and assessment parameters ........................................... 57 3.3.4. Building plan geometry and two-way flexure ..................................................................... 60 3.3.5. Assumed seismic hazard conditions for assessment .......................................................... 62 3.3.6. Analytical fragility curves for URBM exterior wall out-of-plane seismic stability............... 64 3.4. Spatial analysis and estimated distribution of out-of-plane URBM wall collapses in Auckland 68 3.5. Conclusions and recommendations ........................................................................................... 72 3.6. Future work ................................................................................................................................ 73 3.7. Acknowledgements.................................................................................................................... 74 3.8. Disclaimers ................................................................................................................................. 74 3.9. Notation ..................................................................................................................................... 75 3.10. References ............................................................................................................................... 76
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Chapter 4. Seismic considerations for the Art Deco interwar reinforced concrete buildings of Napier, New Zealand ......................................................................................................................................... 81 4.1. Introduction ............................................................................................................................... 81 4.2. Research motivation .................................................................................................................. 82 4.3. Regional seismicity and seismic design requirements ............................................................... 83 4.4. Typological study of Napier’s existing Art Deco buildings ......................................................... 84 4.5. Geometric study of Napier’s existing Art Deco buildings .......................................................... 88 4.5.1. Geometric irregularities ...................................................................................................... 88 4.5.2. Non-structural life-safety hazards ...................................................................................... 89 4.6. Material properties .................................................................................................................... 91 4.7. Column geometry and reinforcement detailing ........................................................................ 93 4.8. Foundations ............................................................................................................................... 99 4.9. Observed damage to similar structures in the Canterbury earthquakes and elsewhere ........ 100 4.10. Summary and conclusions ..................................................................................................... 102 4.11. Acknowledgements................................................................................................................ 104 4.12. References ............................................................................................................................. 105 Chapter 5. In situ out-of-plane testing of unreinforced masonry cavity walls in as-built and improved conditions............................................................................................................................................ 109 5.1. Introduction ............................................................................................................................. 109 5.2. Research context...................................................................................................................... 110 5.2.1. Historical observations of URM cavity wall performance................................................. 110 5.2.2. Predictive models for the OOP performance of solid URM walls ..................................... 111 5.3. Methods and materials ............................................................................................................ 114 5.3.1. In situ building conditions ................................................................................................. 114 5.3.2. Preparation of test wall panels ......................................................................................... 115 5.3.3. Retrofit cavity tie properties ............................................................................................. 118 5.3.4. Test setup and instrumentation ....................................................................................... 119 5.3.5. Wall material properties ................................................................................................... 120 5.4. Test results and discussion ...................................................................................................... 121 5.4.1. Measured wall OOP performance .................................................................................... 121 5.4.2. Conversion of test forces to equivalent earthquake demands ........................................ 125 5.4.3. Comparison of wall strengths to expected demands ....................................................... 127 5.4.4. Equivalent solid wall thickness for use in existing analytical models ............................... 129 5.5. Conclusions and recommendations ......................................................................................... 132
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5.6. Acknowledgements.................................................................................................................. 133 5.7. References ............................................................................................................................... 133 Chapter 6. Ancillary considerations for assessing unreinforced masonry walls for out-of-plane performance ....................................................................................................................................... 139 6.1. Out-of-plane seismic assessment of clay brick masonry cavity walls considering different boundary conditions ....................................................................................................................... 139 6.1.1. Introduction ...................................................................................................................... 140 6.1.2. Testing program ................................................................................................................ 140 6.1.3. One-way vertical flexure without arching action.............................................................. 144 6.1.4. One-way vertical flexure with arching action ................................................................... 151 6.1.5. Conclusions and recommendations .................................................................................. 154 6.1.6. Summary of out-of-plane seismic assessment considerations for clay brick masonry cavity walls ............................................................................................................................................ 156 6.2. Estimating the thrust force on the bounding frame due to arching action of clay brick masonry infill ................................................................................................................................................. 158 6.2.1. Introduction ...................................................................................................................... 158 6.2.2. Pre-existing predictive equations ..................................................................................... 158 6.2.3. Masonry prism crushing strain ......................................................................................... 160 6.2.4. Masonry infill wall OOP rotation....................................................................................... 164 6.2.5. Conclusions and recommendations .................................................................................. 165 6.3. Acknowledgements.................................................................................................................. 166 6.4. References ............................................................................................................................... 166 Chapter 7. Testing of RC frames extracted from a building damaged during the Canterbury earthquakes ........................................................................................................................................ 171 7.1. Introduction ............................................................................................................................. 171 7.2. Research significance ............................................................................................................... 172 7.3. Original construction and earthquake damage ....................................................................... 172 7.4. Experimental investigation ...................................................................................................... 174 7.4.1. Test specimens .................................................................................................................. 174 7.4.2. Test setup .......................................................................................................................... 179 7.4.3. Instrumentation plans....................................................................................................... 181 7.4.4. Loading sequence ............................................................................................................. 182 7.4.5. Material properties ........................................................................................................... 183 7.5. Experimental results ................................................................................................................ 184 7.5.1. H-frame general observations .......................................................................................... 184 ix
7.5.2. H-frame tests – global response ....................................................................................... 186 7.5.3. H-frame tests – local response ......................................................................................... 188 7.5.4. Cruciform tests – general observations ............................................................................ 190 7.5.5. Cruciform tests – global response .................................................................................... 192 7.5.6. Cruciform tests – local response ....................................................................................... 194 7.6. Comparison of predictions and experimental results.............................................................. 194 7.7. Summary and conclusions ....................................................................................................... 196 7.8. Acknowledgements.................................................................................................................. 197 7.9. References ............................................................................................................................... 197 Chapter 8. Seismic risk management of a large public facilities portfolio: a New Zealand case study ............................................................................................................................................................ 201 8.1. Introduction ............................................................................................................................. 201 8.2. Building regulations pertaining to seismic risk mitigation ....................................................... 202 8.3. Rapid seismic building evaluation techniques ......................................................................... 205 8.4. Comparable seismic risk management policies in New Zealand ............................................. 206 8.5. Risk management priorities in the ACPD facilities portfolio .................................................... 208 8.6. Risk profiles and estimated cost liabilities ............................................................................... 214 8.7. Strategies for ongoing seismic risk evaluation and mitigation efforts .................................... 217 8.8. Summary and conclusions ....................................................................................................... 217 8.9. Acknowledgements.................................................................................................................. 218 8.10. References ............................................................................................................................. 219 Chapter 9. Summary, conclusions, and recommendations ................................................................ 225 9.1. Identification and provisional vulnerability assessment of URM and RC buildings and building components .................................................................................................................................... 226 9.2. Testing and assessment of the out-of-plane performance of URM walls ............................... 229 9.3. Testing and assessment of the performance of RC frames ..................................................... 231 9.4. Portfolio management considering earthquake risks and regulations .................................... 234 9.5. Ongoing investigations and proposed research needs ............................................................ 235 9.6. References ............................................................................................................................... 237 Appendix A. Additional information pertaining to commercial building typological categories in Auckland, New Zealand....................................................................................................................... 239 Appendix B. Register of surveyed RC moment resisting frame buildings in Auckland, New Zealand ............................................................................................................................................................ 245 Appendix C. Register of surveyed URM buildings in Auckland, New Zealand ................................... 255 Appendix D. Register of Art Deco buildings in Napier, New Zealand ................................................ 265 x
Appendix E. Displacement-based RC column assessment for a case study interwar building .......... 277 E.1. Introduction ............................................................................................................................. 277 E.2. The case study building ............................................................................................................ 278 E.3. Regional seismicity and performance criteria.......................................................................... 279 E.4. Assessment assumptions and general observations ............................................................... 280 E.5. Measured material properties ................................................................................................. 283 E.6. Structural footprint ratio.......................................................................................................... 283 E.7. Estimating column displacement demands by nonlinear time-history analysis...................... 284 E.8. Estimating column displacement capacities by nonlinear pushover analysis ......................... 287 E.8.1. Assumed material properties............................................................................................ 287 E.8.2. Column geometry, reinforcement detailing, and axial loads............................................ 288 E.8.3. Idealised backbone pushover model ................................................................................ 289 E.8.4. Shear strength reduction due to plastic hinging ............................................................... 293 E.8.5. Flexural strength reduction due to longitudinal bar buckling .......................................... 296 E.8.6. Column %NBS by displacement-based assessment .......................................................... 297 E.8.7. Effects of URM infill walls on column behaviour .............................................................. 298 E.9. Summary and recommendations............................................................................................. 299 E.10. Additional considerations ...................................................................................................... 300 E.11. Acknowledgements ................................................................................................................ 301 E.12. References ............................................................................................................................. 301 Appendix F. Illustrated findings from the invasive inspection of the IMS Hastings building............. 307 Appendix G. Additional data and photographs from the testing of RC frames extracted from a building damaged during the Canterbury earthquakes...................................................................... 313 Appendix H. Worked example calculations ....................................................................................... 335 H.1. URM wall out-of-plane (OOP) collapse potential .................................................................... 335 H.1.1. Case 1 URM wall capacity in vertical flexure .................................................................... 336 H.1.2. Case 1 URM wall demand in vertical flexure .................................................................... 336 H.1.3. Case 1 URM wall capacity in two-way flexure .................................................................. 337 H.1.4. Case 1 URM wall demand in two-way flexure.................................................................. 339 H.1.5. Case 4 URM wall capacity in vertical flexure .................................................................... 340 H.1.6. Case 4 URM wall demand in vertical flexure .................................................................... 341 H.1.7. Case 4 URM wall capacity in two-way flexure .................................................................. 342 H.1.8. Case 4 URM wall demand in two-way flexure.................................................................. 344 H.1.9. Development of fragility curves for URM wall out-of-plane collapse potential .............. 344 xi
H.2. Idealised URM wall push-over curves ..................................................................................... 345 H.3. References ............................................................................................................................... 346 Appendix I. Complete list of references ............................................................................................. 347
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List of figures Figure 1.1. Approximate time periods and contemporary building construction types in New Zealand since significant European settlement began (Credit: John Hare, Holmes Consulting Group) .............. 6 Figure 2.1. Documented and estimated proportions of commercial buildings in Auckland by primary LLRS construction type category ........................................................................................................... 20 Figure 2.2. Documented proportions of commercial buildings in Auckland by number of storeys above grade .......................................................................................................................................... 25 Figure 2.3. Documented proportions and numbers of commercial buildings in Auckland by time period of construction, reconstruction, or seismic retrofit .................................................................. 26 Figure 2.4. Example of estimated typological breakdown by structure type, number of storeys, and time period of construction for construction type category RC moment resisting frame (without infill) .............................................................................................................................................................. 27 Figure 3.1. Proportions of documented commercial URM buildings in Auckland by number of storeys above grade .......................................................................................................................................... 47 Figure 3.2. Proportions of documented commercial URM buildings in Auckland by year of construction, reconstruction, or seismic retrofit .................................................................................. 48 Figure 3.3. Locations of URBM buildings in Auckland Central assessed for CDEM study (inset – zoom on Dominion Road) ............................................................................................................................... 52 Figure 3.4. Post-earthquake observations of out-of-plane failures to URBM buildings in Christchurch .............................................................................................................................................................. 52 Figure 3.5. Most prominent sub-typologies documented from the CDEM study as classified by Russell and Ingham (2010) ................................................................................................................................ 54 Figure 3.6. Summary of typological proportions from CDEM study ..................................................... 54 Figure 3.7. Typical cross-section of URBM building with exterior cavity wall, timber diaphragms and inset diaphragm restraints but without parapet (AS 3700:2011)......................................................... 56 Figure 3.8. URBM wall heights and corresponding proportions of those walls documented for the CDEM study ........................................................................................................................................... 56 Figure 3.9. URBM wall out-of-plane collapse mechanisms in vertical flexure according to different lateral restraint conditions (solid wall left and cavity wall right) ......................................................... 58 Figure 3.10. Plan and elevation of Typology D building (Russell 2010) ................................................ 63 Figure 3.11. Sensitivity of capacity/demand ratio to different conditions (50th percentile performance, PGA = 0.173g, Derakhshan et al. 2014 “parts and components” spectrum) ................. 67 Figure 3.12. Percent of URBM buildings failing (i.e., capacity/demand < 100%) when subjected to varying PGAs, considering different restraint cases, capacity reduction factors and return periods (latter indicated by vertical red lines) ................................................................................................... 69 Figure 3.13. Mapped locations of 763 documented URBM buildings in Auckland and intensity contours from maximum credible earthquake originating from the Wairoa North fault .................... 70 Figure 4.1. Referenced New Zealand cities superimposed on seismic hazard map (adopted from Stirling et al. 2012) ................................................................................................................................ 84 Figure 4.2. Examples of architectural styles in Hawke’s Bay’s Art Deco building stock (Credit: Kevin Q. Walsh) ................................................................................................................................................... 85 Figure 4.3. Years of construction and reconstruction for Napier’s Art Deco building stock ................ 86 Figure 4.4. Traits of Napier’s 1920–1940 non-residential building stock remaining in 2012 with representative number and percentage of buildings, respectively, associated with each trait .......... 87 xiv
Figure 4.5. Unreinforced clay brick masonry (URM) infill wall construction ........................................ 90 Figure 4.6. Distributions of RC frame geometric measurements in Napier’s Art Deco building stock. 91 Figure 4.7. NLTHA target response spectrum for Napier assuming deep soils [derived from NZS 1170.5:2004 (NZS 2004)], maximum horizontal ground motions recorded at four sites near the Christchurch city centre during the February 22, 2011 earthquake, and the geometric mean (GM) of those four ground motions (data from GeoNet 2013) ....................................................................... 101 Figure 5.1. Examples of OOP collapses of URM cavity walls in earthquakes ..................................... 111 Figure 5.2. Test walls and cavity ties................................................................................................... 115 Figure 5.3. Test wall specimens and cavity tie configurations (loading applied on left side of wall cross-sections toward the right; all dimensions in mm) ..................................................................... 117 Figure 5.4. Components of reaction and instrumentation frames for OOP loading of test walls (all dimensions in mm).............................................................................................................................. 120 Figure 5.5. Lateral force-displacement responses with displacement measured at wall mid-height (top edge restraint condition, type and diameter of cavity ties @ average vertical spacing in mm) 123 Figure 5.6. Idealised measured lateral force-drift responses ............................................................. 125 Figure 5.7. Conversion of measured loads from the test condition to the equivalent seismic condition (all dimensions in mm) ........................................................................................................................ 126 Figure 5.8. Sensitivity of two considered OOP wall capacity models to changes in slenderness ratio ............................................................................................................................................................ 132 Figure 6.1. Test components for OOP loading of cavity walls ............................................................ 142 Figure 6.2. Correlation between experimentally-determined effective wall thickness, bw,eff,exp , and various predictive parameters for cavity walls tested in one-way vertical flexure without arching action for use in the Derakhshan et al. (2014) model ........................................................................ 151 Figure 6.3. Correlation between experimentally-determined effective wall thickness, bw,eff,exp , and various predictive parameters for cavity walls tested in one-way vertical flexure with arching action for use in the Angel et al. (1994) model ............................................................................................. 154 Figure 6.4. Sensitivity of two considered OOP wall capacity models to changes in slenderness ratio ............................................................................................................................................................ 155 Figure 6.5. Deflected shape of half-strip segment (recreated with permission from Abrams et al. 1996) ................................................................................................................................................... 159 Figure 6.6. Experimentally measured compressive stress-strain relationship for clay brick masonry prism (Hastings, NZ specimen #1)....................................................................................................... 161 Figure 7.1. Clarendon Tower frame construction indicating locations of extracted test specimens (all units in mm unless noted otherwise; 1 mm = 0.039 in.) .................................................................... 173 Figure 7.2. Beam geometry and reinforcement detailing (Note: column reinforcement and some secondary reinforcement not shown for simplicity; D = deformed bar; R = round bar; all units in mm; 1 mm = 0.039 in.) ................................................................................................................................ 175 Figure 7.3. Post-earthquake damage to the H-frame specimens with crack widths indicated (all units in mm; 1 mm = 0.039 in.) .................................................................................................................... 177 Figure 7.4. Repair of earthquake damage to the H-frame specimens................................................ 178 Figure 7.5. Post-earthquake damage to the cruciform frame specimen............................................ 179 Figure 7.6. Test setup with steel reaction frame and RC test specimens (left is west within the Auckland test site); inserted photos of load actuators and link restraints ......................................... 179 Figure 7.7. Basic instrumentation plans and restraint conditions for the test specimens (Note: L = load cell; D = displacement gauge; all units in mm; 1 mm = 0.039 in.) .............................................. 181 xv
Figure 7.8. Damage state conditions at progressively higher drift levels for the H1 (left, repaired and retrofitted) and H2 (right, repaired only) specimens with approximate portal gauge panel regions indicated (gauges physically located on the opposite side of the specimens) ................................... 185 Figure 7.9. Comparison of the global performance of the two H-frame test specimens (1 kN = 0.225 kips) ..................................................................................................................................................... 187 Figure 7.10. Component contributions to inter-storey drifts of the H-frame specimens .................. 189 Figure 7.11. Damage state conditions at progressively higher drift levels for the C1N (left) and C1S (right) beam specimens with approximate portal gauge panel regions indicated (gauges physically located on the opposite side of the specimens) ................................................................................. 191 Figure 7.12. Comparison of the global performance of the two cruciform test specimens (1 kN = 0.225 kips) ........................................................................................................................................... 193 Figure 7.13. Component contributions to inter-storey drifts of the cruciform specimens ................ 194 Figure 8.1. Maps of priority buildings in the ACPD portfolio (# buildings shown) ............................. 211 Figure 8.2. ACPD building portfolio distributions by documented vulnerability characteristics ........ 213 Figure 8.3. Unit cost estimate models used for initial cost estimating .............................................. 215
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List of tables Table 2.1. Summary of building taxonomies and attributes................................................................. 19 Table 2.2. Summary of primary lateral load resisting system (LLRS) construction type categories ..... 22 Table 2.3. Summary of construction types identified in the Christchurch, New Zealand city centre following the February 2011 earthquake ............................................................................................. 23 Table 2.4. Ranking of top twenty building typological categories by number of estimated buildings 28 Table 2.5. Ranking of top ten building occupancy / usage type attributes for each taxonomy scheme by percentage of estimated total ......................................................................................................... 29 Table 2.6. Ranking of top ten highest average importance levels (NZS 2002) by Auckland Council use category ................................................................................................................................................ 30 Table 2.7. Seismic design and assessment criteria for Auckland buildings (NZS 2002; Cousins 2005) 30 Table 2.8. Buildings sampled for structural footprint ratio and column pushover capacity ................ 34 Table 3.1. Summary of primary lateral load resisting material and structural system attributes for commercial URM buildings in Auckland ............................................................................................... 46 Table 3.2. Ranking of top 5 building typological categories by number of estimated buildings .......... 49 Table 3.3. Ranking of top 10 building occupancy / usage type attributes for each taxonomy scheme by percentage of estimated total ......................................................................................................... 50 Table 3.4. Building design criteria and associated return periods and hazard intensities for Auckland (NZS 2002; Cousins 2005) ..................................................................................................................... 51 Table 3.5. Assumed material properties and capacity reduction factors ............................................. 61 Table 3.6. Mean plan dimensions based on building typology (Russell 2010) ..................................... 63 Table 3.7. Return periods and associated intensities for Auckland assuming shallow soil (NZS 2004; Christophersen et al. 2011; Stirling et al. 2012) ................................................................................... 64 Table 3.8. Capacity/demand ratio for base building in sensitivity analysis .......................................... 66 Table 3.9. Modified Mercalli intensities and assumed corresponding peak ground accelerations ..... 71 Table 3.10. Earthquake scenarios considered and corresponding estimated proportions of out-ofplane (OOP) wall collapses in low-rise URBM buildings in Auckland.................................................... 71 Table 4.1. Material properties of samples extracted from select Art Deco buildings .......................... 93 Table 4.2. Buildings considered for sampling ground floor column geometry..................................... 95 Table 4.3. Ground floor column geometry and detailing ..................................................................... 98 Table 5.1. Geometry and cavity tie detailing of test walls .................................................................. 116 Table 5.2. Summary of retrofit cavity tie locations and properties .................................................... 118 Table 5.3. Summary of measured and calculated masonry material characteristics ......................... 121 Table 5.4. Summary of conversion of measured loads from the test condition to the equivalent seismic condition ................................................................................................................................ 127 Table 5.5. Summary of capacity/demand (C/D) ratios considering equivalent full-height loaded capacities and assuming sites with shallow subsoils .......................................................................... 129 Table 5.6. Summary of test results for walls tested without arching action and comparison to expected results .................................................................................................................................. 130 Table 5.7. Summary of test results for walls tested with arching action and comparison to expected results for load-based capacity ........................................................................................................... 131 Table 6.1. Geometry and cavity tie detailing of test walls .................................................................. 142 Table 6.2. Summary of retrofit cavity tie locations and properties .................................................... 143 Table 6.3. Summary of measured and calculated masonry material characteristics ......................... 144 xviii
Table 6.4. Summary of test results for walls tested without arching action and comparison to expected results .................................................................................................................................. 147 Table 6.5. Summary of test results for walls tested with arching action and comparison to expected results for force-based capacity.......................................................................................................... 153 Table 6.6. Masonry materials test results ........................................................................................... 163 Table 6.7. Comparison of measured wall rotations to estimated wall rotations ............................... 165 Table 7.1. Summary of identification and condition of Clarendon Tower specimens........................ 176 Table 8.1. Associated values and implications of seismic assessment %NBS scores (NZSEE 2014) ... 205 Table 8.2. ACPD’s portfolio by function type ...................................................................................... 209 Table 8.3. Estimated generic seismic mitigation costs across the ACPD portfolio ............................. 216
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Introduction
Chapter 1. Introduction The Committee is confident that there is in this country both the desire for improved building practice and the technical skills to achieve it… More science and less materials are required in our city buildings… Competent men who visited Hawke’s Bay after the disaster do not require to be told the faults of our old building practices – gross faults in design and in construction. We have the men in New Zealand who can do better things, and the building-owners of the future should know how to proceed… The people of New Zealand must realise that the earthquake risk in this country is undoubtedly great, and that all structures, including buildings, if not properly designed and constructed to resist the destructive forces, will suffer in a severe earthquake. In future, the architect and the engineer must pay even greater attention to the importance of earthquake-resistant construction, and must co-operate with the geologist and the seismologist in the practical application of scientific principles. -
Report of the Building Regulations Committee to the New Zealand Parliament 23 June 1931
The words above were written less than five months after the Hawke‘s Bay, New Zealand earthquake of 3 February 1931, which caused the collapse of structures, triggered landslides, and ignited fires, resulting in the deaths of 256 people (Lee et al. 2011). These words remained prophetic following the more recent Christchurch, New Zealand earthquake of 22 February 2011, which was the most intense and damaging earthquake of the Canterbury earthquakes sequence which occurred during 2010–2011 and resulted in the deaths of 182 people within the first 24 hours following the earthquake (Johnston et al. 2014), including 175 due to building failures (Cooper et al. 2012). Reporting on the causes of building failures in the Christchurch earthquake, the Canterbury Earthquakes Royal Commission of Inquiry (Cooper et al. 2012) identified two building structure types as being especially vulnerable to earthquakes:
Load-bearing unreinforced masonry (URM) buildings, which were typically constructed in New Zealand prior to 1935, being a structure type that was responsible 1
Introduction
for 39 fatalities during the February 2011 Christchurch earthquake at 20 different sites; and
Reinforced concrete (RC) frame buildings, which were typically built in New Zealand anytime from the early 1900s, being a structure type that was responsible for 133 fatalities during the February 2011 Christchurch earthquake due to the collapses of the Pyne Gould Corporation (PGC) building and the Canterbury Television (CTV) building.
In their final report (Cooper et al. 2012), the Royal Commission made several recommendations for how the national government, local authorities, building owners, and building industry participants should proceed. In regard to the identification of vulnerabilities and risk awareness, the Royal Commission recommended the following:
Territorial authorities should be required to maintain and publish a schedule of earthquake-prone buildings in their districts;
The engineering and scientific communities should do more to communicate to the public the risk buildings pose in earthquakes, what an assessment of building strength means, and the likelihood of an earthquake;
Industry participants, such as… property managers, should ensure that they are aware of earthquake risks and the requirements for earthquake-prone buildings in undertaking their roles, and in their advice to building owners; [and]
The Ministry of Business, Innovation and Employment [MBIE] should support industry participants’ awareness of earthquake risks and the requirements for earthquake-prone buildings through provision of information and education.
The term ―earthquake-prone building‖ in the recommendations is defined in the New Zealand Building Act (New Zealand Parliament 2004) and the corresponding regulations (New Zealand Parliament 2005) as a building that is likely to have its capacity exceeded in a ―moderate‖ earthquake with an intensity equal to one-third of the intensity of the design basis earthquake (DBE) per the current loadings standards (NZS 2002, 2004) or is otherwise likely to collapse causing injury or death, or property damage to others. Due to the widespread failures in Christchurch of URM buildings, in particular, the Royal Commission made specific recommendations pertaining to URM buildings as follows: 2
Introduction
The detailed assessment of unreinforced masonry buildings that are earthquake-prone should take into account the potential need to… ensure adequate connection between all structural elements of the building so that it responds as a cohesive unit; [and]
The legislation should be further amended to require that, in the case of unreinforced masonry buildings, the out-of-plane resistance of… parapets… and external walls to lateral forces shall be strengthened.
The vulnerabilities and life-safety consequences of URM parapets and external walls to outof-plane collapse during earthquakes are high (Ingham and Griffith 2011; Moon et al. 2014). However, even sophisticated seismic risk studies such as those composed by GNS Science have limited ability to predict out-of-plane URM collapses and the corresponding consequences accurately. In the earthquake loss model reported for the Auckland region, for example, Cousins et al. (2014) noted the following:
A shortcoming of the current modelling is the estimation of casualties arising from the fall of weak brick… un-braced parapets and gables. Currently such casualties are derived as a proportion of the casualties caused by building collapse. The problem with the method is that the fall of weak… parapets and gables becomes common at a shaking intensity of MM7, whereas widespread collapse of weak buildings requires intensities of MM8 and above (MM being Modified Mercalli). The mismatch in intensity means that the numbers of casualties due to the fall of weak brick… unbraced parapets and gables, will be underestimated.
Due to the failures observed in numerous RC buildings, in particular the CTV building, the Royal Commission made the following recommendations:
In the assessment of buildings for their potential seismic performance… the individual structural elements should be examined to see if they have capacity to resist seismic and gravity load actions in an acceptably ductile manner… [and] while the initial lateral strength of a building may be acceptable, critical non-ductile weak links in load paths may result in rapid degradation in strength during an earthquake. It is essential to identify these characteristics and allow for this degradation in assessing potential seismic performance. The ability of a building to deform in a ductile mode and sustain its lateral strength is more important than its initial lateral strength; [and] 3
Introduction
Arising from our study of the CTV building, it is important that the following, in particular, should be examined: the beam-column joint details… [and] the level of confinement of columns to ensure that they have adequate ductility to sustain the maximum inter-storey drifts that may be induced in a major earthquake.
Addressing the need for structural engineers and technical authorities to expand the knowledge and implementation of state-of-the-art design and assessment techniques, the Royal Commission made the following recommendations:
Structural engineers should assess the validity of basic assumptions made in their analyses;
The Ministry of Business, Innovation and Employment [MBIE] should review the New Zealand Society [for] Earthquake Engineering [NZSEE] Recommendations entitled Assessment and Improvement of the Structural Performance of Buildings in Earthquakes [NZSEE 2006] and, in conjunction with engineering practitioners, establish appropriate practice standards or methods for evaluating existing buildings;
Territorial authorities and subject matter experts should share information and research on the assessment of, and seismic retrofit techniques for, different building types; [and]
The universities of Auckland and Canterbury should pursue ways of increasing the structural and geotechnical knowledge of civil engineers entering the profession.
1.1. Research motivation and dissemination Technically assessed risk considerations, building regulatory requirements, and commercial tenant demands in New Zealand have changed since the 2010–2011 Canterbury earthquakes, enhancing the motivation to quickly and accurately assess the capacities of buildings and identify component vulnerabilities under earthquake loads. Thus, the opportunity exists for a unique collaboration between researchers and practitioners to enhance the technical tools available for seismic assessments and to put these tools into practice as soon as possible. In addition to addressing the Royal Commission (Cooper et al. 2012) recommendations listed in the preceding section, the research described in this manuscript was motivated and directed largely by specific requests made to the thesis supervisors from the engineering design industry, government authorities, and building owners who are attempting to address specific 4
Introduction
technical and infrastructure-management issues in the current regulatory and market environment. In accordance with these motivations, some of the technical recommendations made in this manuscript have been implemented into or referenced in proposed future updates to two of the world‘s most referenced guidelines pertaining to seismic assessments of existing buildings (NZSEE 2006; ASCE 2014), with the expectation that more of the included recommendations will be implemented in the future. Design requirements in New Zealand (NZS 2002) prescribe that buildings subjected to design basis earthquake (DBE) actions be designed for ―avoidance of collapse of the structural system… or parts of the structure… representing a hazard to human life inside and outside the structure… [and] avoidance of damage to non-structural systems necessary for… evacuation.‖ Consistent with these requirements, with the primary focus of the Royal Commission recommendations (Cooper et al. 2012), and with New Zealand seismic assessment guidelines NZSEE (2006), the emphasised performance level considered in the research described herein is the ultimate limit state (ULS), which is theoretically equivalent to the life safety (LS) performance level considered in ASCE 41-13 (ASCE 2014). However, the technical recommendations made in this manuscript to mitigate hazard to human life naturally extend to damage mitigation and resiliency strategies as well, which are especially important given the researchers‘ concerns regarding protecting heritage buildings for the use and enjoyment of future generations (Brown et al. 2014).
1.2. Research objectives and scope The primary research objective of the various projects described herein was to advance stateof-the-art knowledge on building typological data and seismic assessment methods so as to directly assist engineering practitioners, building owners, and building authorities to accommodate technical, commercial, regulatory, and heritage preservation motives in the current environment of seismic concerns in New Zealand, with the expectation that many of the findings and recommendations can be applied elsewhere around the world. The aforementioned research motivations for this thesis have come from varied sources with varied motivations of their own, resulting in a research scope that is relatively wide in a technical sense. With the intention of focusing the research on the most earthquakevulnerable types of building construction, however, the technical themes of this thesis are primarily dedicated to seismic assessment techniques for relatively heavy, brittle construction
5
Introduction
(e.g., masonry, concrete, and heavy non-structural building components). In order to address the needs of local building authorities to identify and provisionally assess the seismic vulnerability of a large number of buildings, generic identification, classification, and assessment techniques appropriate to varied structure types were considered and utilised, and such content is considered firstly in this manuscript. Thereafter, the content of this thesis is approximately ordered chronologically by time period of construction type (see Figure 1.1) by reporting on research investigations pertaining to URM, early RC with and without masonry infill, and relatively modern RC, in that order. In order to address the needs of building portfolio owners and stakeholder management entities, the thesis is concluded with a case study detailing seismic risk considerations, risk mitigation strategies, and cost estimating
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practices for a large public facilities portfolio owner.
A. Building Type
1 Unreinforced Masonry 2 Riveted steel moment frames 3 Welded and Bolted steel moment frames 4 Concrete Frame with infill 5 Non-ductile concrete moment frame 6 Ductile concrete moment frames 7 Tilt panel single storey 8 Tilt panel multi-storey 9 Concrete shear wall structures 10 Lightly reinforced partially filled concrete masonry 11 Fully filled concrete masonry 12 Timber Frame B. Element Type
1 Precast concrete floor systems 2 Heavy masonry or plaster cladding 3 Precast Cladding systems Probably Earthquake Prone Possibly Earthquake Prone May have some issues Probably not Earthquake Prone
Figure 1.1. Approximate time periods and contemporary building construction types in New Zealand since significant European settlement began (Credit: John Hare, Holmes Consulting Group)
1.3. Thesis format and chapter content This manuscript is a ―thesis by publications‖ wherein each chapter (and one appendix) represents an article or combination of articles that have, at the time of thesis submission, been published, accepted, or submitted to a publisher for external peer review. Due to the ―thesis by publications‖ format and the similar motivations for the various studies reported in the individual chapters, there is some unavoidable repetition of information throughout the 6
Introduction
manuscript. The following sub-sections include brief summaries of the studies pertaining to each chapter and references to the included publications and other relevant publications. The referenced ―included publications‖ are typically journal articles added to the thesis manuscript with slight changes to writing style (e.g., US English changed to NZ English, numerical in-text citations changed to parenthetical in-text citations, etc.) and to in-text references made to other sections, figures, tables, or appendices within the thesis. The referenced ―relevant publications‖ are conference papers containing similar or ancillary information to that of the ―included publications.‖ 1.3.1. Chapter 2. Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock
The Auckland Council in New Zealand has worked with contracted professional engineers and researchers to assist in identifying and taxonomically classifying structural seismic attributes for the approximately 20,000 commercial buildings in the region, starting with those that are most likely to be seismically vulnerable in order to prioritise buildings for further detailed assessment and, potentially, seismic retrofitting. This study was intended to demonstrate the utility of typological investigations, protocols for extrapolating data while accounting for inspection biases, and best-practice next steps for rapidly assessing the most seismically vulnerable components of a region-wide commercial building stock. Included publication: Walsh, K., Cummuskey, P., Jafarzadeh, R., and Ingham, J. (2016). ―Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock.‖ Journal of Performance of Constructed Facilities, in press. Relevant publications: Walsh, K., Cummuskey, P., Dizhur, D., and Ingham, J. (2014). ―Structural seismic attributes of Auckland‘s commercial building stock.‖ Proceedings of the New Zealand Society for Earthquake Engineering Conference, 21–23 March, Auckland, New Zealand. 1.3.2. Chapter 3. Geometric characterisation and out-of-plane seismic stability of low-rise unreinforced brick masonry buildings in Auckland, New Zealand
Auckland, New Zealand has the largest number of unreinforced masonry (URM) buildings in the country. Information that can be procured through rapid field inspections of URM 7
Introduction
buildings includes the building geometric typologies (e.g., heights, building footprint geometry and isolated versus row configuration), elevation type (e.g., perforated frame versus solid wall), wall construction (e.g., solid versus cavity, number of leaves) and basic construction material type (e.g., clay brick versus stone). On that basis, a survey of the geometric characteristics of a sample of URM buildings located in Auckland was conducted in order to compile a representative distribution of the geometric attributes that are inputs into out-of-plane (OOP) assessment procedures, so as to determine representative distributions of expected OOP performance thresholds against varying peak ground acceleration (PGA) intensities for use in spatial hazard modelling. Included publication: Walsh, K., Dizhur, D., Almesfer, N, Cummuskey, P., Cousins, J., Derakhshan, H., Griffith, M., and Ingham, J. (2014). "Geometric characterisation and out-of-plane seismic stability of low-rise unreinforced brick masonry buildings in Auckland, New Zealand." Bulletin of the New Zealand Society for Earthquake Engineering, 47(2), 139–156. Relevant publications: Walsh, K., Cummuskey, P., Dizhur, D., and Ingham, J. (2014). ―Seismic characterisation of unreinforced masonry buildings in Auckland, New Zealand.‖ Proceedings of the 9th International Masonry Conference, 7–9 July, Guimarães, Portugal. Walsh, K. and Ingham, J. (2013). ―The Earthquake hazard posed by Auckland‘s unreinforced masonry building stock.‖ Proceedings of the 12th Canadian Masonry Symposium, June 2–5, Vancouver, Canada. 1.3.3. Chapter 4. Seismic considerations for the Art Deco interwar reinforced concrete buildings of Napier, New Zealand
Early reinforced concrete (RC) buildings are an important part of the architectural heritage of relatively young countries like New Zealand that historically had limited access to structural iron and steel. A typological study was undertaken in order to provide information on the geometric weaknesses, collapse hazards, material properties, structural detailing, and recommended analysis approaches particular to early RC ―Art Deco‖ buildings in Napier, New Zealand as a resource for professional structural engineers tasked with seismic assessments and retrofit designs for these buildings. The observed satisfactory performance 8
Introduction
of similar low-rise, ostensibly brittle RC buildings in historic earthquakes and the examination of the structural redundancy and expected column drift capacities in these buildings, led to the conclusion that the seismic capacity of these buildings is generally underestimated in simple, force-based assessments. Included publication: Walsh, K., Elwood, K., and Ingham, J. (2015). "Seismic considerations for the Art Deco interwar reinforced-concrete buildings of Napier, New Zealand." Natural Hazards Review, 16(4), 04014035. Relevant publication: Walsh, K. and Ingham, J. (2013). ―Seismic assessment and improvement of Napier‘s Art Deco buildings.‖ Proceedings of the New Zealand Society for Earthquake Engineering Conference, 26–28 April, Wellington, New Zealand. 1.3.4. Chapter 5. In situ out-of-plane testing of unreinforced masonry cavity walls in asbuilt and improved conditions
Relatively little research has been performed pertaining to unreinforced masonry (URM) walls with cavities (i.e., continuous air gaps separating wythes of brick from one another), despite the prominence of cavity masonry construction in various parts of the world. Hence, an experimental testing program was pursued with an emphasis on efficiently retrofitting URM cavity walls to enable the formation of semi-composite to composite behaviour. Test walls were subjected to simulated seismic out-of-plane (OOP) loading using inflatable airbags. The effect on URM cavity wall OOP performance when the walls were bordered by rigid moment resisting reinforced concrete frames was also considered. Included publication: Walsh, K., Dizhur, Y., Shafaei, J., Derakhshan, H., and Ingham, J. (2015). ―In situ out-ofplane testing of unreinforced masonry cavity walls in as-built and improved conditions.‖ Structures, 3, 187–199, 10.1016/j.istruc.2015.04.005.
9
Introduction
Relevant publication: Walsh, K., Dizhur, D., Shafaei, J., Derakhshan, H., and Ingham, J. (2014). ―Out-of-plane in situ testing of masonry cavity walls in as-built and improved conditions.‖ Proceedings of the Australian Earthquake Engineering Society Conference, 21–23 November, Lorne, Australia. . 1.3.5. Chapter 6. Ancillary considerations for assessing unreinforced masonry walls for out-of-plane performance
Based on the experimental test results for out-of-plane (OOP) unreinforced masonry (URM) walls as presented in the preceding chapter and elsewhere, two additional studies were carried out to address shortcomings in existing assessment guidelines. Firstly, a provisional predictive model was proposed to assist engineers is determining an equivalent solid wall thickness for URM cavity walls retrofitted with various tie conditions. The equivalent solid wall thickness could then subsequently be applied in existing OOP predictive models for solid URM walls. Secondly, the effects of the thrust forces acting on the bounding frame elements that arise due to OOP arching action of masonry infill were considered, corresponding to the assessment criteria of ASCE 41-13 (ASCE 2014). An existing theoretical model for predicting the thrust force was amended with an empirical equation used to estimate the crushing strain of masonry based on experimental testing of clay brick masonry prisms and mortar cubes. Included publications: Walsh, K., Dizhur, D., Derakhshan, H., Griffith, M., and Ingham, J. (2015). ―Out-of-plane seismic assessment of clay brick masonry cavity walls considering different boundary conditions.‖ Proceedings of the 12th North American Masonry Conference, 17–20 May, Denver, Colorado. Walsh, K., Dizhur, D., and Ingham, J. (2015). ―Estimating the thrust force on the bounding frame due to arching action of clay brick masonry infill.‖ Journal of Structural Engineering, in review (third round). Relevant publication: Giaretton, M., Walsh, K., Dizhur, D., da Porto, F., and Ingham, J. (2016). ―Retrofitting URM cavity walls for out-of-plane composite behaviour.‖ Proceedings of the 16th International Brick and Block Masonry Conference, 26 – 30 June, Padova, Italy.. 10
Introduction 1.3.6. Chapter 7. Testing of RC frames extracted from a building damaged during the Canterbury earthquakes
Three precast RC moment resisting frame specimens were extracted during the demolition of the Clarendon Tower in Christchurch after sustaining earthquake damage in the 2010–2011 Canterbury earthquakes. These specimens were subjected to quasi-static cyclic testing as part of a research program to determine the reparability of the building. The test specimens were amongst the largest beam-column joint sub-assemblies that have been tested in New Zealand, and are thought to be amongst the largest test specimens worldwide to be extracted from an earthquake-damaged building. The testing of these specimens provided direct evidence of the reparability of earthquake-damaged ductile structures, and also of the ductility capacity of buildings designed using 1980s New Zealand design standards. Furthermore, the cyclic test results were used to verify the predicted inelastic demands applied to the specimens during the 2010–2011 Canterbury earthquakes. Included publication: Walsh, K., Henry, R., Simkin, G., Brooke, N., Davidson, B., and Ingham, J. (2015). ―Testing of RC frames extracted from a building damaged during the Canterbury earthquakes.‖ ACI Structural Journal, 113(2), 349–362. 1.3.7. Chapter 8. Seismic risk management of a large public facilities portfolio: a New Zealand case study
The Auckland Council Property Department (ACPD) in New Zealand engaged in a proactive effort to assess its portfolio of approximately 3500 buildings, prioritise its building assets for seismic retrofit, and forecast construction costs for long-term planning. This case study was carried out with the intended audience for dissemination being primarily those professionals in the field of facilities management, including asset planners around the world dealing with similar regulatory environments pertaining to earthquakes as that which currently exists in New Zealand. From a technical research perspective, the typological classification and rapid vulnerability evaluation of buildings within the ACPD portfolio was intended to provide valuable comparative data for risk modellers in New Zealand and in other countries with British-style historical construction.
11
Introduction
Included publication: Walsh, K., Jafarzadeh, R., Short, N., and Ingham, J. (2015). ―Seismic risk management of a large public facilities portfolio: a New Zealand case study.‖ Facilities, 34(13/14). Relevant publications: Walsh, K., Short, N., Cummuskey, P., and Ingham, J. (2013). ―Seismic assessment and retrofit prioritisation of Auckland Council‘s property portfolio.‖ Proceedings of the Australian Earthquake Engineering Society Conference, 15–17 November, Hobart, Australia. 1.3.8. Appendix E. Displacement-based RC column assessment for a case study interwar building
A case study assessment of a Hawke‘s Bay Art Deco building was carried out in order to exemplify a displacement-based seismic investigation of Art Deco RC columns while appropriately accounting for regional seismicity, material properties, building component interaction, column geometry, and reinforcement detailing. The results for the considered case study indicated that the IMS Hastings building in Hawe‘s Bay is likely to deform torsionally in most time-history cases scaled to the design basis earthquake due largely to eccentrically placed URM infill walls and lift shafts. Nonetheless, the structural redundancy of the building and contribution from stiffening components considered in the model, including the RC slab and URM infill walls, were expected to limited the building‘s interstorey drifts such that the %NBS of the columns remained relatively high. Included publication: Walsh, K., Dizhur, D., Liu, P., Masoudi, M., and Ingham, J. (2015). ―Displacement-based RC column assessment for a case study interwar building.‖ Sesoc Journal, in press. Relevant publications: Walsh, K., Liu, P., Dizhur, D., and Ingham, J. (2013). ―Detailed seismic assessment of a Hawke‘s Bay Art Deco case study building.‖ Proceedings of the New Zealand Concrete Industry Conference, 3–5 October, Queenstown, New Zealand.
12
Introduction
1.4. References ASCE (American Society of Civil Engineers). (2014). ―Seismic evaluation and retrofit of existing buildings.‖ ASCE 41-13, Reston, Virginia. Brown, J., Walsh, K., and Cummuskey, P. (2014). ―The four R‘s – reduce risk, raise resilience: Local authority priorities and the Auckland perspective on engineering requirements for heritage buildings.‖ 4th Australasian Engineering Heritage Conference, 24–26 November, Christchurch, New Zealand. Cooper, M., Carter, R., and Fenwick, R. (2012). Canterbury Earthquakes Royal Commission final report, volumes 1–7, Royal Commission of Inquiry, Christchurch, New Zealand, . Cousins, W.J., Nayyerloo, M., and Delinge, N.I. (2014). ―Estimated damage and casualties from earthquakes affecting Auckland.‖ GNS Science Consultancy Report 2013/324, Institute of Geological and Nuclear Sciences (GNS), Lower Hutt, New Zealand. Ingham, J., and Griffith, M. (2011). ―Performance of unreinforced masonry buildings during the 2010 Darfield (Christchurch, NZ) earthquake.‖ Australian Journal of Structural Engineering, 11(3), 207–224. Johnston, D., Standring, S., Ronan, K.R., Lindell, M., Wilson, T., Cousins, J., Aldridge, E., Ardagh, M.W., Deely, J.M., Jensen, S., Kirsch, T., and Bissell, R. (2014). ―The 2010/2011 Canterbury earthquakes: Context and cause of injury.‖ Natural Hazards, 73, 627–637. Lee, J., Bland, K., Townsend, D., and Kamp, P. (2011). ―Geology of the Hawke‘s Bay area.‖ Institute of Geological & Nuclear Science (GNS), Lower Hutt, NZ, 1:250 000 geological map 8, 1 sheet +93 p. Moon, L., Dizhur, D., Senaldi, I., Derakhshan, H., Griffith, M., Magenes, G., and Ingham, J. (2014). ―The demise of the URM building stock in Christchurch during the 2010–2011 Canterbury earthquake sequence.‖ Earthquake Spectra, 30(1), 253–276. New Zealand Parliament. (1931). Report of building regulations committee, House of Representatives, New Zealand Government, Wellington, New Zealand. New Zealand Parliament. (2004). Building Act 2004, Department of Building and Housing, Ministry of Economic Development, New Zealand Government, Wellington, New Zealand. New Zealand Parliament. (2005). Building, (specified systems, change the use, and earthquake-prone buildings) regulations, Department of Building and Housing, Ministry of Economic Development, New Zealand Government, Wellington, New Zealand. NZS (Standards New Zealand). (2002). ―Structural design actions, Part 0: General principles.‖ NZS 1170.0:2002, Incorporated Amendments 1–5. Australian Standards (AS)
13
Introduction
and Standards New Zealand (NZS) Joint Technical Committee BD-006, Wellington, New Zealand. NZS (Standards New Zealand). (2004). ―Structural design actions, Part 5: Earthquake actions – New Zealand.‖ NZS 1170.5:2004, Standards New Zealand Technical Committee BD006-04-11, Wellington, New Zealand. NZSEE (New Zealand Society for Earthquake Engineering). (2006). Assessment and improvement of the structural performance of buildings in earthquakes, recommendations of a NZSEE study group on earthquake risk of buildings, Incorporated Corrigenda No. 1 & 2, New Zealand Society for Earthquake Engineering, Wellington, New Zealand.
14
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock
Chapter 2. Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock As territorial authorities, government agencies, and other large asset owners were responding to regulatory and market forces in the wake of the 2010–2011 Canterbury, New Zealand earthquakes by assessing and planning retrofits for buildings determined to be particularly vulnerable to earthquakes, an opportunity existed to identify and taxonomically classify structural seismic attributes in the largest regional commercial building stock in New Zealand. To that end, the Auckland Council proactively sought to assess thousands of commercial and industrial buildings across the Auckland region. As part of the Auckland Council program, a targeted sample out of a total of approximately 19,885 commercial buildings in the Auckland region was assessed with varying amounts of typological data recorded including lateral load resisting system type, number of storeys, and time period of construction. Engineers, risk modellers, building regulators, and civil defence officials in other cities around the world can consider the Auckland Council program as a case study for how survey data may be collected, classified, and extrapolated to account for typological information not yet recorded as well as selection biases, and how relatively precise yet rapid assessments may be carried out for especially vulnerable building construction types and components.
2.1. Introduction Few seismic retrofit mandates in the world are as comprehensive as that encapsulated in the New Zealand Building Act (New Zealand Parliament 2004). The Building Act requires that local authorities identify buildings that are considered ―earthquake-prone,‖ which is defined in the Building Act and the corresponding regulations (New Zealand Parliament 2005) as buildings that are likely to have their capacity exceeded in a ―moderate‖ earthquake with an intensity equal to one-third of the intensity of the current design basis earthquake (DBE) and are likely to collapse causing injury, death, or property damage to others. Note that the seismic risk mitigation mandates in New Zealand, in contrast to other places (City of Los Angeles 1949, 1985; City of Portland 2004; City of San Francisco 1993; City of Seattle 2009; City of Vancouver 2012; FEMA 2009; Newman 1976; Paxton et al. 2015; Tokyo Metropolitan Government 2011), do not pertain particularly to certain types of building 15
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock
materials, components, or structural systems, notwithstanding that certain types are more likely to be considered earthquake-prone. The estimated population of 1.4 million people within the Auckland local authority area accounts for about one-third of the nation‘s population (Statistics New Zealand 2013), and Auckland‘s prominent role in New Zealand‘s economy requires Auckland‘s building stock to be resilient to natural disasters. As of 2012, Auckland‘s economy accounted for an estimated 37% of New Zealand‘s GDP, and the region‘s economic growth rate had outpaced New Zealand‘s national economic growth seven of the preceding eleven years (Monitor Auckland 2012). Hence, a major natural disaster in Auckland would directly or indirectly affect many people throughout New Zealand. Correspondingly, the Auckland Plan (Auckland Council 2012) prioritises ―built resilience to natural hazards‖ and explicitly lists ―ground shaking hazards‖ for targeted risk mitigation. In response to the national regulations and local plans, Auckland Council composed its own policy for actively assessing commercial buildings in the region (Auckland Council 2011). For purposes of the Auckland Council investigation, the term ―commercial‖ buildings is defined as including those traditionally considered places of business (e.g., offices and shops), as well as industrial buildings and multi-unit, rent-tenanted residential buildings of four or more storeys. Low-unit and low-rise residential buildings (e.g., single-family houses and low-rise condominiums) were excluded, and non-occupied monuments, kilns, chimneys, and ruins have not been considered in the investigation thus far. The Auckland Council worked with contracted professional engineers and researchers to assist in identifying and taxonomically classifying structural seismic attributes for the approximately 20,000 commercial buildings in the region, starting with those that were most likely to be seismically vulnerable in order to prioritise buildings for further detailed assessment and, potentially, seismic retrofitting. Identifying those buildings most at risk to an earthquake in such a large, varied,
and
geographically
dispersed
commercial
building
stock
warranted
the
implementation of a rapid building evaluation program.
2.2. Research motivation As part of past hazard modelling projects in New Zealand, pilot studies were performed to determine building typological information relevant to structural engineers and seismological hazard researchers (Uma et al. 2008). However, these studies were often limited by the 16
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock
availability of structural plans and specifications and, in particular, efficient procurement of typological information on a large scale. Hence, many of the pilot studies consisted mostly of visual inspections from street walks in a few smaller cities within the country, with the typological building attributes then being extrapolated to other, larger cities in proportion to census data and commercial real estate figures. The Auckland Council study documented herein was intended to demonstrate the utility of typological investigations, protocols for extrapolating data while accounting for selection biases, and best-practice next steps for rapidly assessing the most seismically vulnerable buildings and building components in a region-wide commercial building stock. The procurement of typological information pertaining to structural seismic attributes of buildings permits risk modellers to compose more accurate simulations, structural engineers to develop assessment and retrofit techniques for representative buildings that can be implemented efficiently on a regional scale, large asset owners to more precisely evaluate their risk profiles in comparison to the regional building stock, and local policy makers to make more informed decisions for mitigating the impacts of regional hazards. Auckland was considered to serve as an appropriate city for a case study into rapid taxonomical classification given that it houses one-third of the country‘s population and has been isolated from major, infrastructuredestroying earthquakes such as those that other major New Zealand population centres have experienced in the past 150 years, subsequently resulting in those other areas having more homogenous building stocks today. Hence, Auckland is expected to have the largest and most varied building stock in the country, containing representative examples of nearly all types of buildings throughout New Zealand as well as in other countries with British-style historical construction.
2.3. Rapid seismic building evaluations Auckland Council‘s experience with access to building plans for its historic buildings is likely consistent with that of other large portfolio owners in that as-built structural plans are rarely maintained due to a lack of periodic use (in contrast to architectural, fit-out, cladding, HVAC, and utility plans which are more regularly referenced for ongoing maintenance efforts). Furthermore, even in cases where as-built structural building plans are available, non-recorded building additions and alterations, potentially hazardous non-structural elements, and deteriorations in the condition of structural elements are not necessarily indicated on such plans. Hence, an on-site building structural evaluation program was 17
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock
necessary, and a preferred evaluation method was one able to be used rapidly and costeffectively to cull a large number of buildings down to the buildings most likely to be seismically vulnerable. Most of the historically prominent guidelines regarding rapid seismic assessments of buildings pertained to buildings that had been damaged by earthquakes (ATC 1985, 1989, 2000). However, in more recent years, the importance of rapid visual screening for potential future seismic hazards has been acknowledged by the publication of standards in the United States (FEMA 2002), Canada (CSA 2014), and New Zealand (NZSEE 2014), amongst others. These rapid evaluation techniques have also been leveraged with modern tools such as spatial mapping (e.g., ArcGIS) and virtual environments (e.g., Google Street View), as used in the Auckland Council program to a limited extent and used elsewhere to a greater extent (Ploeger et al. 2015). The initial evaluation procedure (IEP) as published by the New Zealand Society for Earthquake Engineering (NZSEE 2014) is the method for carrying out rapid seismic assessments preferred by most local authorities in New Zealand, including the Auckland Council. The IEP is a provisional, qualitative screening procedure that provides an approximate assessment of seismic risk following a cursory site visit. The IEP can be applied knowing only the building height, structural system, time period of construction, importance level (NZS 2002), and qualitative evaluation of the building‘s geometric irregularities (i.e., building configurations that may result in undesirable behaviour under earthquake loading). Regarding the time period of construction, knowledge of the materials and loadings standards to which a building was designed heavily influences assumptions about its seismic capacity (Uma et al. 2008; MacRae et al. 2011). The importance level is largely dictated by the building‘s size (in terms of total floor area), occupancy capacity, and intended post-disaster functions (e.g., hospitals and buildings housing emergency response services are assessed to a higher importance level and, hence, compared to a more intense DBE).
2.4. Building taxonomies and data considered With the intention of leveraging the data being procured through Auckland Council‘s assessment processes for application to hazard models, two specific building taxonomical classification schemes were considered – the Global Earthquake Model (GEM 2013) and RiskScape (King and Bell 2006; GNS 2010). Charleson (2011) reviewed other existing structural taxonomies and explained the suitability of GEM on a global scale. RiskScape is the preferred hazard modelling system of the Institute of Geological and Nuclear Sciences 18
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock
(GNS) in New Zealand, so classifying building data to its taxonomy provides the most regional relevance and correlates with previous typological studies performed in New Zealand (Uma et al. 2008). The general attribute groups considered by each taxonomy are listed in Table 2.1. Attribute groups marked with ―X‖ in Table 2.1 are the attribute groups that have been considered in the Auckland Council study thus far. Note that the most significant difference between the two classification schemes is that RiskScape considers more attributes related to occupancy and costs, whereas GEM considers structural attributes more comprehensively. Table 2.1. Summary of building taxonomies and attributes GEM (2013) Attribute group
Data availability
Direction Material of the lateral load resisting system Lateral load resisting system Height (including # of storeys above ground) Date of construction or retrofit Occupancy (Usage type) Building position within a block Shape of the building plan Structural irregularity Exterior walls
* X X
Roof
*
Floor Foundation system
* *
X X X * * * *
RiskScape (GNS 2010) Data Attribute group availability Construction type
X
Floor height Storeys Year of construction Use category
* X X X
Wall cladding class Roof cladding class Roof pitch Floor type
* * * *
Condition Contents value Deprivation Index Employee daily income Floor area Footprint area Occupancy (# people) Parapet Replacement-cost Vehicle value Vehicles
*
** ** ** * **
Notes: X = attribute information currently considered within the current Auckland Council inspection program; * = attribute information that will be considered within planned, future inspection programs; ** = attribute information available through other data sources such as Quotable Value NZ
The current database of commercial buildings in Auckland includes 19,885 buildings, representing nearly all of the commercial buildings in the Auckland region as determined by geocoding identified commercial buildings and comparing their spatial coverage to all areas zoned for commercial use in the region. Hence, estimates of the total number or percentage of buildings within a particular typology as presented herein are considered as if 19,885 is the 19
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock
total number of commercial buildings in Auckland. Potentially, an estimated 1000–4000 commercial buildings may be missing from this total due to being located in small, mixed-use industrial-residential areas. Furthermore, not all of the identified 19,885 buildings have been inspected. Where appropriate, a distinction has been made between whether quantitative values as presented herein represent ―documented‖ or ―estimated‖ buildings as well as whether percentages noted represent proportions including or excluding unknown building attribute data. Furthermore, a bias exists in the documented data. Investigators have prioritised older buildings most likely to be vulnerable to earthquakes, producing a partiality in the data pool to buildings of particular construction types. These biases have been accounted for as much as possible in extrapolations, as noted herein. 2.4.1. Primary lateral load resisting system (LLRS) construction type categories
In the Auckland Council database, 4672 (approximately 23% of the total) buildings were documented with a specific primary lateral load resisting system (LLRS) construction type category. The representative proportions of commercial buildings by LLRS construction type category both as documented and estimated (i.e., extrapolated to the total of 19,885 buildings) are shown in Figure 2.1. The estimated number of buildings and representative proportion by LLRS construction type are listed in Table 2.2 in accordance with the
% of building stock represented by trait
respective GEM (2013) and RiskScape (GNS 2010) taxonomical classifications. 50% 42%
40% 29%
29%
30%
23%
21%
20%
15% 10% 10%
10%
7% 7%
5%
1%
0% RC shear wall RC moment Steel braced Light timber or tilt-up resisting frame or steel panel frame moment (including resisting hybrid frame wall/frame and frame with infill)
Brick masonry (URM, including stone masonry)
Concrete masonry
RiskScape (GNS 2010) construction type category Documented % excluding unknown Estimated % of total
Figure 2.1. Documented and estimated proportions of commercial buildings in Auckland by primary LLRS construction type category
The bias in the documented inspection data for primary LLRS construction type category was assumed to result in an over-representation of unreinforced masonry (URM) and light timber 20
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock
buildings because these are the two construction types associated with older (i.e., pre-World War II), heritage-designated facilities which were prioritised for initial inspection. URM and light timber building construction types often appear similar at street view due to the prominence of brick veneer on light timber framed buildings in New Zealand, and historic construction documentation is often lacking. Hence, while light timber framed buildings are not usually considered especially vulnerable to earthquakes, they have likely been inspected in disproportionately high numbers by default of attempting to identify all URM buildings in Auckland per the recommendations of the Canterbury Earthquakes Royal Commission (Cooper et al. 2012). For purposes of estimating the proportions of construction type categories in the total commercial building stock in Auckland (assumed to be 19,885 buildings as noted previously), it was assumed that all URM buildings had been identified and documented due to efforts related to a concurrent research program described in Walsh et al. (2014), resulting in a proportional representation for URM of 5% (see Figure 2.1) of the total Auckland commercial building stock. Note that the total number of estimated and documented URM buildings of 1090 (see Table 2.2) is close to the number of URM buildings of 1026 estimated for the Auckland region by Russell and Ingham (2010). Furthermore, note that Cousins (2005) also assumed that Auckland‘s URM buildings represented 5% of its total commercial building stock. The estimated percentage of the total Auckland commercial building stock consisting of light timber buildings was capped at 15% per Cousins (2005), based on more complete commercial building data from Wellington, New Zealand. Kam et al. (2011) documented the construction types of buildings in the city centre of Christchurch, Canterbury, New Zealand following the February 2011 earthquake (see Table 2.3). However, the Kam et al. (2011) data included both residential and commercial buildings. Hence, all residential buildings in the Kam et al. (2011) data set were assumed to be constructed of light timber or URM [consistent with the observations of Uma et al. (2008)], and the numbers of light timber and URM buildings in the Kam et al. (2011) data set were artificially reduced such that the proportions of these buildings within the hypothetical commercial building stock were 15% and 5%, respectively (see the last column of Table 2.3).
21
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock Table 2.2. Summary of primary lateral load resisting system (LLRS) construction type categories
GEM (2013) Material of the LLRS, level 1
Material of the LLRS, level 2
CR (Concrete, reinforced) or SRC (Concrete, composite with steel section)
CIP (Cast-in-place concrete) or PC (Precast concrete) or CIPPS (Cast-inplace prestressed concrete) or PCPS (Precast prestressed concrete)
S (Steel)
SR (Hot-rolled steel members)
RiskScape (GNS 2010)
LLRS, level 1
Est. # total
LWAL (Wall)
4146
LFM (Moment frame) LFINF (Infilled frame) LDUAL (Dual frame-wall system)* LFM (Moment frame) LFINF (Infilled frame) LH (Hybrid LLRS) LWAL (Wall)
W (Wood)
MUR (Masonry, unreinf.)
MR (Masonry, reinforced)
WLI (Light wood members)
CLBRS (Fired clay solid bricks) or CLBRH (Fired clay hollow bricks) and/or RCB (Reinforced concrete bands) STRUB (Rubble (field stone) or semi-dressed stone) or STDRE (Dressed stone) CBH (Concrete blocks, hollow) and RS (Steelreinforced)
6134 2038
LWAL (Wall)
20.8 % 30.8 % 10.2 %
119
0.6%
1311
6.6%
14
0.1%
7
0.0% 14.9 %
2969
LFINF (Infilled frame) LDUAL (Dual frame-wall system)* LH (Hybrid LLRS)
Est. % of total
8
0.0%
3
0.0%
3
0.0%
1076
5.4%
LWAL (Wall)
14
0.1%
LWAL (Wall)
2043
10.3 %
Total
19,885 100%
Est. # total
Est. % of total
4146
21%
8291
42%
Steel braced frame or steel moment resisting frame
1332
7%
Light timber
2983
15%
Brick masonry (URM, including stone masonry)
1090
5%
Concrete masonry
2043
10%
Construction type category RC shear wall or tilt-up panel RC moment resisting frame (including hybrid wall/frame and frame with infill)
Total
Notes: * The dual frame-wall system specifically was documented as a frame with a masonry wall RC = reinforced concrete URM = unreinforced masonry
22
19,885 100%
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock
As a result, proportions of the other construction types within the commercial building stock could be estimated for the hypothetical Christchurch city centre. Note that the reduction of the number of URM buildings in Table 2.3 was especially artificial considering that the Canterbury (Christchurch) region of New Zealand is expected to have a much larger percentage of URM buildings as a portion of its building stock compared to the Auckland region (Russell and Ingham 2010). Hence, the values in the last two columns of Table 2.3 are indicative only of data artificially manipulated to direct assumptions for the Auckland-based study reported herein. Table 2.3. Summary of construction types identified in the Christchurch, New Zealand city centre following the February 2011 earthquake
RiskScape (GNS 2010) construction type category
Documented commercial and residential (Kam et al. 2011) # buildings
% total
Estimated commercial* # buildings
% commercial total
RC shear wall 91 3% 91 6% Tilt-up panel 176 6% 176 12% RC moment resisting frame 357 13% 357 24% RC moment resisting frame with 209 8% 209 14% infill Steel braced frame or steel moment 138 5% 138 9% resisting frame Light timber 1028 38% 230* 15%* Brick masonry (URM, including 505 18% 80* 5%* stone masonry) Concrete masonry 228 8% 228 15% Total 2732 1509 Notes: * Numbers artificially reduced from the commercial and residential total as described in the text
Proportions of the building stock consisting of steel frames (braced and moment resisting) and concrete masonry (which is almost always at least partially grouted and reinforced in historical New Zealand construction practices) were assumed to be accurately represented in the documented data from the Auckland inspections (see Figure 2.1). The remainder of the total commercial building stock in Auckland was assumed to consist of reinforced concrete (RC) construction. The Auckland Council inspectors did not distinguish between RC shear wall and tilt-up panel construction, so these construction type categories were combined for purposes of this study (see Figure 2.1 and Table 2.2). The RiskScape (GNS 2010) taxonomy does not distinguish between RC moment resisting frames with and without infill, so these categories were combined in some parts of this study (see Figure 2.1). Relative proportions of RC shear wall/tilt-up panel construction and RC moment resisting frame (with or without 23
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock
infill) construction were assumed to be 1:2 per the Kam et al. (2011) data set (see Table 2.3). Note that the estimated proportions of the total commercial building stock in Auckland consisting of RC shear wall/tilt-up panel construction and RC moment resisting frame (with or without infill) construction of 21% and 42% (see Figure 2.1), respectively, were close to the proportions determined in the artificially reduced Kam et al. (2011) data set of 18% and 38%, respectively (see the last two columns of Table 2.3). The change from documented proportion to estimated proportion of RC shear wall/tilt-up panel construction in Figure 2.1 (from 1% to 21% of the commercial buildings stock) seems especially disproportionate, but the researchers theorised that field inspectors may have often categorised such buildings inappropriately as RC moment resisting frames due to the relative ease of assessing frame systems compared to shear wall systems in the IEP, as well as the difficulty in distinguishing RC shear walls from RC moment resisting frames with infill due to the prominent use of heavy plasters and paints on the exteriors of buildings in Auckland. Furthermore, tilt-up panel construction, in particular, is likely to be far more prominent in distant industrial suburbs of the Auckland region that have not been surveyed proportionately to the relatively denser urban city and village centres. 2.4.2. Number of storeys
In the Auckland Council database, 7488 buildings (approximately 38% of the total) were documented with a specific number of storeys above grade, although Auckland Council simplified the inspection process by capping the recorded number of storeys at eight or more, as shown in Figure 2.2. Furthermore, for typological groupings to include multiple attributes (e.g., structure type, number of storeys, and time period of construction), buildings with a number of storeys below eight were subsequently grouped into categories of 1–3 storeys and 4–7 storeys, consistent with previous typological groupings used in New Zealand (Uma et al. 2008). The selection bias in the documented data for number of storeys above grade likely resulted in an over-representation of taller buildings due to the initial emphasis on inspecting buildings near the city centre as well as the inherent higher profile of taller buildings and the corresponding higher consequence associated with their collapse. Hence, the total number of estimated buildings with 8+ storeys (295) was capped at the current number of buildings
24
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock
documented with 8+ storeys, and proportional extrapolations were made only for buildings
% of building stock represented by trait
with fewer than 8 storeys. 45% 40%
40%
40%
35% 30% 25% 20% 15% 9%
10% 5%
4%
4% 2%
1%
1%
0% 1
2
3 4 5 6 Number of storeys above grade
7
8+
Documented % of buildings excluding unknown
Figure 2.2. Documented proportions of commercial buildings in Auckland by number of storeys above grade
2.4.3. Time period of construction, reconstruction, or retrofit
Knowledge of the relevant design standards to which a building was constructed heavily influences assumptions about its seismic capacity (Uma et al. 2008; MacRae et al. 2011) and is especially influential in regards to the seismic assessment score derived from the IEP (NZSEE 2014). Generally speaking, older buildings are perceived to be more vulnerable to earthquakes, particularly buildings of most structure types designed prior to 1976, when a modern understanding of building ductility was implemented into the loadings standard. Ductility, as considered here, is the ability of a building to reach its peak strength and continue deforming under earthquake demands without weakening. In the Auckland Council database, 19,592 (approximately 99% of the total) buildings have been documented with a particular or approximate year of construction, reconstruction, or seismic retrofit associated with the primary LLRS. For typological groupings to include multiple attributes (e.g., structure type, number of storeys, and age of construction), buildings were grouped into time periods consistent with major updates to the loading standard and with previous typological groupings used in New Zealand (Uma et al. 2008; Fenwick and MacRae 2009; NZSEE 2014). The time period groups considered were pre-1935, 1935–1965, 1966–1976, 1977–1992, and 1993+. The representative proportions of the commercial 25
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock
building stock associated with these simplified time period groupings are illustrated in Figure 2.3. Uma et al. (2008), by comparison, estimated approximate proportions of 44% for pre1977, 28% for 1977–1992, and 28% for 1993+ construction for all of New Zealand based on limited pilot studies of smaller cities, which would indicate that Auckland‘s building stock
% of building stock represented by trait
may be slightly older relative to the rest of the country. 30% 26%
25%
23%
20%
19% 17%
15%
15%
10% 5% 0% Pre-1935 1935-1965 1966-1976 1977-1992 1993+ Time period of construction/reconstruction/retrofit Documented % excluding unknown
Figure 2.3. Documented proportions and numbers of commercial buildings in Auckland by time period of construction, reconstruction, or seismic retrofit
Given that only approximately 1% of the total commercial building stock has not yet been associated with an approximate time period of construction, the need to adjust extrapolation assumptions to account for selection bias was greatly reduced in this case. Were fewer buildings documented with appropriate time periods of construction, however, it would be important prior to extrapolating to identify those buildings with construction types common to all time periods (e.g., light timber construction was common in Auckland from pre-1935 through to 1993+) compared to those buildings with construction types common to limited time periods (e.g., most URM buildings in Auckland were constructed pre-1935 with the remainder being constructed prior to 1965). Historical building standards and industry design guidelines could be referenced to identify contemporary construction material and system types in lieu of more detailed information. Note also that Russell and Ingham (2010) estimated the total number of URM buildings in Auckland (seemingly quite accurately based on the current Auckland Council building inspection database) based solely on a historical review of population growth in the region.
26
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock 2.4.4. Typological groupings by structure type, number of storeys, and time period of construction
To facilitate typological groupings conducive to assigning accurate building fragility functions within seismic hazard models, the three primary structural attribute categories of structure type, number of storeys, and time period of construction were combined in a hierarchical fashion as exemplified for the RC moment resisting frame (without infill) construction type category in Figure 2.4. Note that the sum of all proportions charted in Figure 2.4 equals 30.8%, which is the total proportional representation associated with the
0.29%
0.21%
0.32%
1%
0.23%
0.18%
1.71%
1.22%
1.90%
2%
1.10%
3%
1.39%
4%
3.72%
5%
4.23%
6%
5.21%
5.80%
7%
3.35%
Estimated % of total commercial building stock represented by trait
GEM (2013) taxonomical classification ―LFM (Moment frame)‖ in Table 2.2.
0% 8+ storeys 1–3 storeys 4–7 storeys RC moment resisting frame (without infill) construction type by number of storeys and time period of construction Pre-1935 1935-1965 1966-1976 1977-1992 1993+
Figure 2.4. Example of estimated typological breakdown by structure type, number of storeys, and time period of construction for construction type category RC moment resisting frame (without infill)
The twenty most prominent building typological groupings by estimated percentage of the total commercial building stock are listed in Table 2.4, representing a subtotal of 72% of all of Auckland‘s commercial buildings. Note the dominance of low to mid-rise RC moment resisting frames in the Auckland commercial building stock. Additional and expanded tabulated typological information is included in Appendix A. 2.4.5. Occupancy / usage type and importance level
Another component of risk that must be quantified in models, along with hazard and vulnerability, is consequence. Both GEM (2013) and RiskScape (GNS 2010) account for attributes related to the functional use or occupancy of the buildings being considered. As noted in Table 2.1, GEM and RiskScape have different applications for the word 27
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock
―occupancy,‖ but both consider building usage type somewhere within their taxonomical schemes. In the amalgamated database, 19,796 buildings (nearly 100% of the total) have been documented with a particular use category. The ten most prominent use categories by estimated percentage of the total commercial building stock are listed in Table 2.5 for each of the two taxonomies, representing over 90% of all of Auckland‘s commercial buildings. Table 2.4. Ranking of top twenty building typological categories by number of estimated buildings # storeys
Time period of constr./reconstr./ retrofit
Estimated # buildings
Estimated % of total
1–3
1935-1965
1154
5.8%
1–3
1977-1992
1036
5.2%
1–3
1935-1965
956
4.8%
LWAL (Wall)
1–3
1935-1965
912
4.6%
LWAL (Wall) LFM (Moment frame)
1–3
1977-1992
858
4.3%
1–3
1966-1976
842
4.2%
Fired clay bricks
LWAL (Wall)
1–3
Pre-1935
795
4.0%
W (Wood)
Light wood
LWAL (Wall)
1–3
1935-1965
767
3.9%
9
RC
RC
LFM (Moment frame)
1–3
1993+
739
3.7%
10
MR
LWAL (Wall)
1–3
1966-1976
709
3.6%
11
RC W (Wood)
LWAL (Wall)
1–3
1966-1976
697
3.5%
LWAL (Wall)
1–3
1977-1992
688
3.5%
1–3
Pre-1935
666
3.3%
1–3
1993+
612
3.1%
Rank
Material, level 1*
Material, level 2*
1
RC
RC
2
RC
RC
3
RC
4
MR
5
RC
RC Concrete blocks RC
6
RC
RC
7
URM
8
12
Concrete blocks RC Light wood
LLRS, level 1 LFM (Moment frame) LFM (Moment frame) LWAL (Wall)
13
RC
RC
14
RC Light wood
LWAL (Wall)
1–3
1966-1976
560
2.8%
16
RC W (Wood) RC
LFM (Moment frame) LWAL (Wall)
RC
1–3
Pre-1935
551
2.8%
17
RC
RC
LWAL (Wall) LFINF (Infilled frame)
1–3
1935-1965
500
2.5%
Light wood
LWAL (Wall)
1–3
1993+
491
2.5%
Light wood
LWAL (Wall)
1–3
Pre-1935
443
2.2%
15
18 19
W (Wood) W (Wood)
20
RC
RC
LFM (Moment frame)
4–7
1935-1965
378
1.9%
Subtotal
-
-
-
-
-
14,354
72%
Notes: * GEM (2013) material nomenclature has been simplified in order to fit within this table appropriately. Please see Table 2.2 for further information on material nomenclature.
28
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock Table 2.5. Ranking of top ten building occupancy / usage type attributes for each taxonomy scheme by percentage of estimated total GEM (2013) Rank
1 2 3
Occupancy category COM3 (Offices, professional/technical services) COM1 (Retail trade) EDU99 (Education, unknown type)
RiskScape (GNS 2010) % of total incl. unknown 55.5% 12.2% 5.6%
4
RES2 (Multi-unit, unknown type)
5.5%
5 6 7 8
OCO (Other occupancy type) EDU1 (Pre-school facility) COM4 (Hospital/medical clinic) COM6 (Public building)
3.3% 3.0% 2.7% 2.0%
9
IND2 (Light industrial)
1.8%
10
COM2 (Wholesale trade and storage (warehouse)) Subtotal
Use category Commercial Business Education Residential Dwellings Industrial Manufacturing, Storage Hospital, Clinic Lifeline Utilities Community Religious Territorial Authority/Civil Defence
% of total incl. unknown 67.8% 8.6% 5.3% 4.0% 2.7% 2.0% 2.0% 1.7% 1.4%
1.7%
Clear Site
1.2%
93%
-
97%
Table 2.6 includes a listed ranking of the ten most prominent use categories by average importance level (NZS 2002), where the listed use categories are retained in the Auckland Council nomenclature for specificity. The importance level can be indicative of the number of people within a building as well as its post-disaster pertinence. Information from building standards and seismic hazard models most relevant to Auckland‘s buildings and importance levels, in particular, is summarised in Table 2.7. Most buildings in Auckland would likely be considered to have 50-year design working lives for assessment and retrofit design purposes, but some buildings of particular significance to the community could be considered for 100year design working lives. For design and assessment purposes, most buildings would be assigned importance levels 2 or 3. Importance level 2 applies to normal structures, and importance level 3 applies to buildings containing larger crowds, valuable assets, or serving important functions as defined in the loadings standard (NZS 2002). Buildings in Auckland that would most regularly be considered for importance level 3 criteria would likely include schools, libraries, and town halls. Hence, while most buildings would be considered for a DBE with an average return period of 500 years, higher-profile buildings will need to be considered for less frequent events. The average return periods listed in Table 2.7 correspond with DBE design parameters to include strength, ductility, serviceability, and durability.
29
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock Table 2.6. Ranking of top ten highest average importance levels (NZS 2002) by Auckland Council use category Use category (Auckland Council)
Avg. import. level
Petrol holding tanks Utility station Emergency services Mass transit station Government Prison Airfield Hospital Courts and judicial services Events centre
4.0 3.7 3.7 3.3 3.2 3.1 3.1 3.0 3.0 2.8
The Modified Mercalli (MM) scale is used to describe the damage and intensity experienced by people at a particular location. MM7 and MM8 intensities approximate the range of hazards relevant to the Auckland region, as shown in Table 2.7. MM7 intensity is associated with slight to moderate structural damage in well-built ordinary buildings, while MM8 intensity implies considerable structural damage with partial collapse of well-built ordinary buildings (Lindeburg and McMullin 2011). Table 2.7. Seismic design and assessment criteria for Auckland buildings (NZS 2002; Cousins 2005) Design life
Importance level
Importance level comment
Average return period for DBE
Approx. MM intensity
2
Normal structures
1/500
MM6.8
3
Crowds or valuable assets
1/1000
MM7.2
2
Normal structures
1/1000
MM7.2
3
Crowds or valuable assets
1/2500
MM7.6
50 years 100 years
2.5. Building and component vulnerabilities Consistent with those buildings recognised by the Canterbury Earthquakes Royal Commission (Cooper et al. 2012) as being particularly vulnerable to earthquakes, two LLRS construction types were prioritised for identification and rapid evaluation in the Auckland Council program:
Load-bearing URM buildings, which were typically constructed in Auckland between 1880 and 1940, being a construction type that was responsible for 39 fatalities during the February 2011 Christchurch earthquake at 20 different sites; and 30
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock
RC moment resisting frame buildings, which were typically built in New Zealand anytime from the early 1900s, being a construction type that was responsible for 133 fatalities during the February 2011 Christchurch earthquake due to the collapses of the Pyne Gould Corporation (PGC) building and the Canterbury Television (CTV) building.
As of May 2015, Auckland Council had recorded seismic assessments for 7644 buildings (approximately 38% of the total of 19,885 buildings), with the majority of the assessments (81% of the 7644 inspected buildings) being IEPs and the remainder being more detailed assessments. Of these, 1938 buildings (25% the 7644 inspected buildings) had been identified as potentially earthquake-prone. It the Auckland Council team members‘ belief that, given the targeted inspection program, nearly all of the buildings likely to be identified by the IEP as potentially earthquake-prone have already been identified. However, the IEP has the following known limitations:
Time period of construction is heavily weighted in the vulnerability rating as determined in the IEP, resulting in potentially misleading results. The fatal collapses of the two relatively modern RC moment resisting frame buildings during the 2011 Christchurch earthquake, constructed in 1966 (PGC) and 1986 (CTV), brought greater attention to deficiencies in newer-type RC construction, particularly where some columns in these buildings were not designed with appropriately ductile reinforcement detailing;
The vulnerability ratings as determined by the IEP are effectively qualitative and are generally not reliably precise enough to stratify buildings by relative vulnerability within a particular typological grouping (e.g., URM buildings of 1–3 storeys); and
The vulnerability ratings as determined by the IEP are generally representative of the global structural performance (i.e., base shear capacity/demand ratio) rather than the performance of individual components of the building.
Hence, while the Auckland Council‘s use of the IEP was appropriate for assessing a large, varied stock of commercial buildings in the first instance and permitting the Auckland Council to calibrate its sense of regional vulnerability by identifying typological groupings and proportions as presented herein, such qualitative inspection techniques do little to inform best-practice next steps. Considering the two construction types emphasised by Cooper et al. 31
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock
(2012), the Auckland Council carried out quantitative, relatively precise, and yet relatively rapid assessments [compared to the more common detailed seismic assessment procedures used in New Zealand (NZSEE 2006)], of URM buildings as well as particular RC moment resisting frame buildings. The focus of the study carried out specific to URM buildings (Walsh et al. 2014) was on the out-of-plane capacity of URM walls and parapets, consistent with the observed life-safety failure mechanisms of URM buildings in past earthquakes (Cooper et al. 2012). As a result of this study, Walsh et al. (2014) were able to stratify a large number of low-rise URM buildings in terms of relative vulnerability and estimated that significant life-safety improvements to these buildings could be made with relatively noninvasive retrofits.
2.6. RC moment resisting frames with potentially non-ductile columns Whereas the vulnerability of URM walls to out-of-plane collapse from earthquake demands and the extent of retrofit intervention necessary can be relatively easily determined with knowledge of the visible wall and floor geometry (Walsh et al. 2014), determining the vulnerability and extent of retrofit intervention necessary for RC moment resisting frame buildings depends largely on identifying the geometry and reinforcement detailing of RC columns. Motivated largely by the collapse of the CTV building which was constructed in 1986 with relatively non-ductile ―gravity‖ columns permitted by the RC design standard used between 1982 and 1995 (NZS 1982), the New Zealand Department of Building and Housing [now part of the Ministry of Business, Innovation and Employment (MBIE)] commissioned consultants to compile a register of RC frame buildings throughout the country with three storeys or more that were granted building permits or consents between 1982 and 1995. A total of 168 buildings in Auckland were identified as meeting the selection criteria (see Appendix B), although some eligible buildings were likely overlooked in the process. After the register was completed, the consultants qualitatively selected the presumably least ductile column on each floor of each of the 168 buildings and compared the column geometry and reinforcement detailing to the performance criteria of the current RC design standard (NZS 2006) in order to identify potentially non-ductile columns. The effect of axial load demand on column performance was not considered at this stage. The qualitative process carried out by engineering consultants on behalf of MBIE to identify potentially non-ductile RC columns provided a useful first step in a rapid seismic vulnerability assessment program, but as described herein, the researchers considered two additional criteria for the considered RC 32
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock
frame buildings – structural footprint ratio and column pushover capacity – in order to better stratify the buildings in regard to seismic vulnerability, consistent with similar exercises completed for different RC building stocks (Walsh et al. 2015). 2.6.1. Structural footprint ratio
The ratio of the sum of RC column and in-plane shear wall cross-sectional areas to the total building footprint area in the direction of lateral loading is called the ―structural footprint ratio.‖ This ratio is most commonly considered at the ground floor level and in respect to two orthogonal directions of lateral loading. The structural footprint ratio represents a simplistic parameter for rapidly assessing seismic vulnerabilities in a RC building stock, but it has been found to have a relatively strong empirical correlation with the performance of RC buildings in historic earthquakes (Glogau 1980). Furthermore, roof drift demands can be provisionally estimated in relation to structural footprint ratios and design base shear demands (Wallace 1994; Burak and Comlekoglu 2013). From the set of buildings registered by MBIE for the Auckland region, structural floor plans were obtained and reviewed for 25 buildings as listed in Table 2.8, which comprised a range of building heights, design dates (as indicated on available construction drawings), and floor system types representative of the expanded MBIE register of 168 buildings. For simplicity and because only 13 of the 25 considered buildings were found to have shear walls in addition to moment resisting frames, the minimum combined structural footprint ratios listed in Table 2.8 represent a 1:1 ratio of summing columns and in-plane shear walls. However, other researchers have remarked upon the relative prominence of shear walls in RC buildings that were found to have performed well in past earthquakes, suggesting that the effective structural footprint ratio be determined by summing RC columns and in-plane RC shear wall footprint areas using a 0.37:1 ratio (Glogau 1980) or a 0.5:1 ratio (Hassan and Sozen 1997). The average minimum combined structural footprint ratio (i.e., column ratio plus the minimum in-plane shear wall ratio) of approximately 1% shown in Table 2.8 was determined by weighting the structural footprint ratios of the 25 buildings by their respective gross footprint areas at the ground storey. The average minimum combined structural footprint ratio for the considered buildings is low compared to preferred modern seismic design values for mid-rise RC structures (Burak and Comlekoglu 2013), suggesting that the roof drift demands for many of the buildings listed in Table 2.8 may be high relative to the design base shear demands. 33
Rapid identification and taxonomical classification of structural seismic attributes in a region-wide commercial building stock Table 2.8. Buildings sampled for structural footprint ratio and column pushover capacity # Design storeys date 4 5 5 5 5 5 6 6 6 7
Jul-86 Jan-87 Feb-87 Feb-84 Sep-86 Jun-85 Apr-87 Nov-83 Sep-87 Jan-85
8
Mid-86
9 9 10 11 11 13 13
Jun-86 Nov-87 May-85 1986 May-88 Jul-88 Jul-84 Mid87 Oct-95
14 14 15 16 16 19 19
Floor system type Double tees Hollowcore Double tees Hollowcore Hollowcore Rib and infill Hollowcore Hollowcore Hollowcore Rib and infill Hollowcore & Rib and infill Hollowcore ? Double tees ? Hollowcore Double tees Double tees
Gross footprint area of ground storey (m2) 787 648 690 903 1085 2076 1896 951 1882 673
Column footprint ratio (%) 1.60 1.52 0.44 0.46 0.44 0.60 0.66 0.69 0.24 0.64
In-plane shear wall footprint ratio (%) xydirection direction 0.00 0.00 0.05 0.05 0.27 0.40 0.84 0.86 0.74 0.50 0.00 0.00 0.25 0.40 0.00 0.00 1.64 1.06 0.00 0.00
Minimum combined footprint ratio (%) 1.60 1.57 0.71 1.30 0.93 0.60 0.92 0.69 1.30 0.64
0.66 1.46 0.63 1.77 1.48 1.32 1.93 1.31 1.23 2.41
Min. displacement ductility capacity 7.01 100
EQ risk category
Prone / high risk Moderate risk Low risk Complies with current loading standard
Approx. relative risk (NZSEE 2014)
Potentially affected by the Building Act (2004) and Health & Safety Act (1992)
Non-compliant with current loading standard (NZS 2004)
> 25 times 10–25 times 5–10 times 2–5 times 1–2 times
X X
X X X X X
< 1 time
8.3. Rapid seismic building evaluation techniques ACPD‘s experience with access to building plans for its historic buildings is likely consistent with that of other large portfolio owners in that as-built structural plans are rarely maintained due to a lack of periodic use (in contrast to architectural, fit-out, cladding, HVAC, and utility plans which are more regularly referenced for ongoing maintenance efforts). Furthermore, even in cases where as-built structural building plans are available, non-recorded building additions and alterations, non-structural elements, and deteriorations in the condition of structural elements are not necessarily indicated in such plans. Hence, an on-site building structural evaluation program is necessary, and a preferred evaluation method is able to be used rapidly and cost-effectively to cull a large portfolio of buildings down to the buildings most likely to be seismically vulnerable. Most of the historically prominent guidelines regarding rapid seismic assessments of buildings pertain to buildings that have already been damaged by earthquakes (ATC 1985, 1989, 2000). However, in recent years, the importance of rapid visual screening for potential future seismic hazards has been acknowledged by the publication of standards in the United States (FEMA 2002), Canada (CSA 2014), and New Zealand (NZSEE 2014), for example. These rapid evaluation techniques have also been leveraged with modern tools such as spatial mapping (e.g., ArcGIS) and virtual environments (e.g., Google Street View), as used in the ACPD program to a limited extent and used elsewhere to a greater extent (Ploeger et al. 2015). Seismic building evaluations in New Zealand are generally performed in three general stages as prescribed in the NZSEE (2014) assessment guidelines – preliminary assessment, initial 205
Seismic risk management of a large public facilities portfolio: a New Zealand case study
seismic assessment (ISA), and detailed seismic assessment (DSA). Preliminary assessments and ISAs are both considered ―rapid‖ in that they can be performed completely within a day, and generally within a few hours, for most individual buildings. The initial evaluation procedure (IEP) is the method for ISAs preferred by most local authorities in New Zealand and is a provisional, qualitative screening procedure that provides an approximate assessment of seismic risk in terms of %NBS following a cursory site visit. In comparison, a detailed seismic assessment (DSA) typically provides more detail and involves comprehensive calculations and/or computer models. A preliminary assessment for purposes of ACPD‘s rapid building evaluation program is comprised of the IEP but without an assessment of geometric irregularities (i.e., building configurations that may result in undesirable behaviour under earthquake loading) such that the procedure can be applied off-site knowing only the building height, structural system, year of design, and importance level (NZS 2002). Regarding the design year, knowledge of the materials and loadings standards to which a building was designed heavily influences assumptions about its seismic capacity (Uma et al. 2008; MacRae et al. 2011). The importance level is largely dictated by the size of the building (in square metres of total floor space), the number of regular and maximum occupants, and the building‘s intended post-disaster functions (e.g., buildings housing Auckland Council‘s Civil Defence and Emergency Management response teams are assessed to a higher importance level and, hence, a more intense DBE).
8.4. Comparable seismic risk management policies in New Zealand To ensure correlation with state-of-the-art engineering and property management practices elsewhere, a survey of owner policies for peer facilities in New Zealand was warranted. For example, Wellington City Council (WCC) is a peer local authority that as of April 2013 owned 683 buildings (N. Brown, personal correspondence, 26 April 2013). Any building deemed potentially earthquake-prone by an ISA has been tagged with publicly viewable notices, and some buildings (e.g., those containing large numbers of children) have been closed until further assessments or retrofits are commissioned. A DSA will be commissioned for every building owned by WCC with an ISA score of below 33%NBS. Regardless of the ISA score, however, WCC‘s health and safety policy is to commission a DSA for every building within their portfolio that could subject them to action under the Health and Safety in Employment Act (New Zealand Parliament 1992), primarily those buildings that house Council staff or are accessible to the public. As of April 2013, WCC considered 128 of its
206
Seismic risk management of a large public facilities portfolio: a New Zealand case study
683 buildings to be subject to this health and safety policy. WCC has commissioned soil borings at several of its building sites in order to better understand amplification and liquefaction potential. As of March 2014, WCC had demolished one minor building and applied for consent to demolish another, due largely to earthquake-related concerns (N. Brown, personal correspondence, 12 March 2014). Note that on an international scale, Wellington has a high seismic hazard compared to Auckland‘s moderate seismic hazard (NZS 2002; ASCE 2014). The New Zealand Department of Corrections (Corrections) owns over 870 buildings across the country and commissioned an engineering consultant to assess these buildings using the IEP. Thereafter, Corrections‘ seismic risk committee developed a risk-framework which was largely quantitative in nature and took into account IEP scores, health and safety issues related to seismic hazards that may not normally be captured by the IEP, and functional utilisation of the buildings (based on hours of use). These three categories were assigned weighted scores (30%, 50%, and 20% respectively) in order to compute an overall risk value. The risk value spectrum was divided into four action categories for the buildings to be assigned response plans within 12, 24, or 36 months or to consider the building for future disposal (Linstrom and Sharpe 2013). The New Zealand Ministry of Education (MoE) owns and manages approximately 16,000 buildings across the country, excluding ancillary structures (such as utility sheds and boiler houses). The MoE formed an Engineering Strategy Group (ESG) to provide technical leadership on structural assessments and strengthening of school buildings. That group has advised that the MoE‘s buildings be prioritised based largely on structural configuration, with particular emphasis assigned to buildings constructed of unreinforced masonry (URM), buildings of two or more storeys with heavy construction, especially reinforced concrete (RC), and single storey buildings with large open areas (C. Armstrong, personal correspondence, June–August 2013). Given that 80% of the buildings in the MoE‘s portfolio are constructed primarily of timber, and that many of the geometric and detailing configurations of its buildings are consistent across the portfolio, the ESG pursued physical testing of exemplar buildings and used the results from the testing in published guidelines for the seismic evaluation of timber framed buildings (Sheppard and Brunsdon 2013).
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Seismic risk management of a large public facilities portfolio: a New Zealand case study
8.5. Risk management priorities in the ACPD facilities portfolio ACPD‘s acceptable risk thresholds and strategies for prioritising building evaluations can be considered in comparison to the peer owner policies summarised previously. In comparison to WCC, the buildings in the ACPD portfolio are far more numerous (over 3500 compared to WCC‘s 683) and are located in a region with a relatively lower seismic hazard, so defaulting to commissioning DSAs for all occupied buildings and all buildings with ISA scores lower than 33%NBS would likely result in an inefficient use of resources. In comparison to Corrections and the MoE, ACPD‘s buildings are used in a wider range of service and commercial functions (see Table 8.2, which was produced by the author) and have a greater variety of structure types, so a more qualitative strategic review is preferable. However, the importance of protecting building occupants, considering building utilisation rates, and attempting to leverage the evaluation of representative buildings within the portfolio to steer work on similar buildings are all considerations from peer owners that ACPD has incorporated into its seismic risk mitigation program. ACPD has also implemented the recommendations from the New Zealand Property Management Centre of Expertise (PMCoE 2013) which include the following:
[Set] an expectation that where hazards are identified, all practical steps are taken to remove or minimise the risk posed… Employers need to exercise judgement in this respect;
Being “earthquake prone” [per an ISA] doesn’t necessarily mean that your building should not be occupied but it does mean that an expert engineering assessment [DSA] should be obtained as soon as possible; and
To ensure that no unnecessary cost is incurred, agencies need to form a view of where the tolerable risk point is in relation to a particular building and balance this against the requirement to keep staff and the public safe.
208
Seismic risk management of a large public facilities portfolio: a New Zealand case study Table 8.2. ACPD’s portfolio by function type
21
Average documented floor area per building (m2) 380
Estimated total floor area for all buildings (m2) 7,985
Arts/Museum/Cultural Centre
30
922
27,648
Cafe/Restaurant
21
451
9,470
Camp/Hut/Lodge Building
67
249
16,710
Car Parking Building
18
4819
86,743
Chapel/Crematorium
12
574
6,885
Childcare Facility
6
333
2,000
Commercial/Investment Building
282
1870
527,433
Community Centre
30
813
24,391
Community Facility
226
1270
286,960
Community Hall
96
390
37,444
Community House
21
301
6,319
Council Office/Service Centre
70
6594
461,605
Event/Entertainment Centre
2
86
172
Farm Building
44
214
9,403
Fire Station
13
304
3,952
Horticulture/Glasshouse
22
126
2,782
Housing for the Elderly
460
146
67,223
Kitchen
9
244
2,194
Laundry
33
134
4,408
Library
38
1596
60,641
Local Board Accommodation
1
690
690
Resident-Owned Subsidised Housing
38
287
10,908
Public Display/Education Building
10
245
2,449
Public Toilet/Changing Shed Pumphouse
911 13
120 163
109,225 2,115
Recreation/Leisure Centre Residential
14 590 41 24 74
4202 337 211 1592 764
58,828 198,953 8,638 38,213 56,506
Stadium/Grandstand/Arena Swimming Complex/Aquatic Centre Transfer Station/Refuse Facility Velodrome
21 38
1068 2049
22,425 77,856
16 2
512 ?
8,192 ?
Visitor/Information Centre Works Depot/Utility Building
11 197
272 772
2,995 152,146
Mixed Use Not Recorded
51
1414
72,129
3
1567
4,702
Total
3576
-
2,479,337
Primary Function Type
# Buildings
Animal Welfare Centre/Pound
Residential Garage Shade/Shelter Sports Facility
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Seismic risk management of a large public facilities portfolio: a New Zealand case study
ACPD considers its ―risk point‖ as the product of three components, being vulnerability, hazard, and consequence. Any appropriate seismic evaluation program must account for all three of these factors. Initially, the only data available for the buildings in the ACPD‘s portfolio (held in a SAP database platform) were street address, number of assigned occupants (available numbers included staff and elected representatives but not visitors or patrons), and functional type of each building (see Table 8.2). Hence, the rapid evaluation program was prioritised based on perceived risk as derived from these attributes, in which location [see Figure 8.1(a), which was produced by the author] was used as a preliminary proxy for vulnerability based on the age of design (with field assessments targeted initially to geographic areas of the region known to have been settled and built up earlier) and as a proxy for hazard (with South Auckland being closest to known active faults) (Kenny et al. 2011). The consequence component of risk was considered in relation to the number of assigned occupants and functional type wherein core service buildings that are used to provide public services directly to the community and are often occupied by Auckland Council associates as well as members of the public were prioritised for evaluation [see Figure 8.1(b)]. The core service function types are bolded and shaded in Table 8.2. The buildings prioritised based on the initial round of portfolio filtering were identified to the facilities maintenance managers, who were asked to provide the best available information on design age (or, alternatively, construction age), structure type, and number of storeys above grade for each building. Information provided by the maintenance managers was supplemented by data contained within ArcGIS spatial map files from Quotable Value (QV) Limited, a state-owned valuation information services provider. Attained QV information included approximate design ages and heights for some buildings but did not include structure type. Floor areas were documented for as many buildings as possible (see Table 8.2), and if not available from the maintenance manager or QV, were generally approximated as the footprint area measured from an Auckland Council GIS map multiplied by the number of visible storeys (from photographs, site visits, or Google Street View).
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Seismic risk management of a large public facilities portfolio: a New Zealand case study
(a) All ACPD buildings (3576)
(b) ACPD core service buildings sized by number of assigned occupants (663)
(c) ACPD core service buildings designed prior to 1976 sized by number of assigned occupants (226)
(d) ACPD buildings designed prior to 1976 and constructed primarily of URM or RC frames sized by number of assigned occupants (108)
Figure 8.1. Maps of priority buildings in the ACPD portfolio (# buildings shown)
As noted previously, knowledge of the relevant design standards to which a building was constructed heavily influences assumptions about its seismic capacity (Uma et al. 2008; MacRae et al. 2011) and is especially influential in regards to the %NBS score derived from the IEP (NZSEE 2014). Hence, where such information was available, buildings were 211
Seismic risk management of a large public facilities portfolio: a New Zealand case study
assigned to one of the following age groups: pre-1935, 1935–1965, 1966–1976, 1977–1992, and 1993+. Generally speaking, older buildings are perceived to be more vulnerable to earthquakes [see Figure 8.1(c)], particularly buildings of most structure types designed prior to 1976, when a modern understanding of building ductility was implemented into the loadings standard. Ductility, as considered here, is the ability of a building to reach its peak strength and continue deforming under earthquake demands without weakening. Consistent with the MoE priorities and those buildings recognised by the Canterbury Earthquakes Royal Commission (Cooper et al. 2012) as being particularly vulnerable to earthquakes, two structure types were prioritised for identification and rapid evaluation in the ACPD program:
Load-bearing URM buildings, which were typically constructed in Auckland between 1880 and 1940, being a structure type that was responsible for 39 fatalities during the 2011 Christchurch earthquake at 20 different sites; and
RC frame buildings, which were typically built in New Zealand anytime from the early 1900s, being a structure type that was responsible for 133 fatalities during the 2011 Christchurch earthquake due to the collapses of the Pyne Gould Corporation (PGC) building and the Canterbury Television (CTV) building.
Hence, the next iteration of prioritisation for initial evaluations was correlated with those ACPD buildings constructed with potentially vulnerable structure types [see Figure 8.1(d)]. Note that the buildings mapped in Figure 8.1(d) include buildings outside the core services portfolio as URM walls may be more dangerous to passers-by in close proximity to buildings than to building occupants during earthquakes (Moon et al. 2014). Note also the progressive culling of the ACPD building stock from its entirety down to the most potentially at-risk buildings (at least those that were documented with relevant attributes of vulnerability and consequence) in sequence from Figures 8.1(a)–1(d). Hazard was considered insofar as the buildings are spatially distributed with some being located nearer to known active faults (Kenny et al. 2011) and known soft soils sites (Edbrooke 2001). One notable exception exists to the previously described prioritisation by structural vulnerability. Contrary to most structure types, RC frame buildings constructed in New Zealand prior to the 1960s are not necessarily more vulnerable than their more modern 1960s–80s counterparts, as they are typically low-rise and have more redundant structural 212
Seismic risk management of a large public facilities portfolio: a New Zealand case study
elements. In contrast, more modern RC frame buildings are generally taller with fewer redundant elements and greater geometric irregularities (NZSEE 2014). The fatal collapses of the two relatively modern RC frame buildings during the 2011 Christchurch earthquake, constructed in 1966 (PGC) and 1986 (CTV), brought greater attention to deficiencies in newer-type RC construction, particularly where some columns in these buildings were not designed with ductile reinforcement detailing. Whereas the vulnerability of URM walls to out-of-plane collapse from earthquake demands and the extent of retrofit intervention necessary is relatively easily determined with knowledge of the wall and floor geometry (Walsh et al. 2014a), the vulnerability and extent of retrofit intervention necessary for RC frame buildings depends largely on reinforcement detailing and displacement demands which are not as easily determined without a complete DSA (Walsh et al. 2014b). Furthermore, despite the relatively small number of buildings in the ACPD portfolio constructed of RC frames [see Figure 8.2(a)], this type of building constitutes the most significant portions of the ACPD portfolio in terms of both floor area and number of assigned occupants. Hence, multi-storey RC frame buildings in the ACPD core services portfolio with assigned occupants were prioritised firstly to be evaluated through DSAs over all other buildings, and those RC frame buildings included buildings constructed as recently as the late 1980s [an era of design which is also prominent across the ACPD portfolio per Figure 8.2(b)]. Figures 8.2(a) and
80%
% of building stock represented by trait
% of building stock represented by trait
8.2(b) were created based on available data for 894 and 1598 buildings, respectively. 77%
60% 45%
40%
37% 32%
20%
20% 9%
7%
17% 11%
10% 5%
2% 1%
5%
7% 4%
5% 2% 1%
2%
0% RC shear RC moment Steel braced Light timber Brick wall or tilt up resisting frame or steel (and timber masonry (and panel frame (and moment moment stone hybrid resisting frame) masonry) wall/frame) frame
# buildings
floor area
Concrete masonry
0%
Advanced design (and other)
40%
39%
35% 32% 30%
30%
29% 24%
25%
24%
20% 18%
20%
17%
14% 15%
15%
13% 11%
10% 5%
10% 5%
0% Pre-1935
# occupants
(a) Structure type [per GNS (2010) category]
1935-1965 # buildings
1966-1976 floor area
1977-1992 # occupants
1993+
(b) Design age
Figure 8.2. ACPD building portfolio distributions by documented vulnerability characteristics
Seismic mitigation mandates, such as the one currently enforced in New Zealand, are often perceived as being in conflict with other social objectives and legislation, such as that pertaining to heritage preservation (New Zealand Parliament 1993). ACPD has identified 217 buildings within its portfolio that are listed with either Heritage New Zealand or the
213
Seismic risk management of a large public facilities portfolio: a New Zealand case study
Auckland Council heritage register. Such heritage registration will impose strict limitations on both seismic retrofit and disposal options. Auckland Council‘s consideration of heritage buildings specifically is addressed in other literature (Brown et al. 2014).
8.6. Risk profiles and estimated cost liabilities As of March 2015, ACPD has thus far commissioned seven building retrofits, ten DSAs, 319 IEPs, and 434 preliminary evaluations on the buildings in its portfolio. For predictions of the entire portfolio‘s risk profile, the results of the completed evaluations have been marginally weighted in accordance with the structure type and age distributions shown in Figure 8.2 to account for the bias of the current assessments toward buildings most likely to be at risk. ACPD estimates that approximately 6% of its portfolio by number of buildings is potentially at high risk (earthquake-prone), approximately 17% is potentially at moderate risk, approximately 25% is at low risk, and the remainder (approximately 52%) is very low risk and theoretically compliant with the current loadings standard (NZS 2004). One of the reasons for predicting a relatively low percentage of high risk buildings is that approximately 90% of the buildings in the ACPD portfolio where the number of storeys above grade is known are single storey buildings, which suggests a relatively low risk exposure across the complete ACPD portfolio. Preliminary, empirical models for estimating the cost of commissioning a DSA for an individual building are shown in Figure 8.3(a) for Auckland (eleven data points) and Wellington (six data points), respectively. Note that these preliminary models for DSA costs do not account for differences in structure type, importance level, existing %NBS, target %NBS (desired for assessment or intended for retrofit), or specific DSA methodology. Furthermore, ACPD expects that by grouping buildings into packaged DSA projects they may keep the cost of DSA per building lower than is indicated by the models in Figure 8.3(a). Note that DSAs are generally expected to be less expensive in Auckland than they are in Wellington, most likely due to the higher seismicity in Wellington and associated increased complexity of analysis and liability for the engineering consultants performing the DSAs. Much of the research focus on earthquake-related construction costs pertains to benefit-cost assessments regarding the extent of seismic retrofits and serviceability repairs following actual earthquakes or hypothetical earthquakes expected during the service life of individual buildings, as summarised in other literature (Alani and Khosrowshahi 2007). In contrast,
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Seismic risk management of a large public facilities portfolio: a New Zealand case study
ACPD is responding to legal mandates and attempting to quantify and reduce its life-safety risk exposure across a large portfolio as efficiently as possible. The near-term, effectively binary decision to retrofit or dispose/change-use of a relatively large number of buildings considering service, community, and heritage values takes precedent, at least initially, over decisions related to the extent of retrofit to be considered for individual buildings (except in the case of those few buildings needed for civil defence activities). Hence, the use of basic predictive models for seismic retrofit construction (SRC) costs is appropriate for quantifying ACPD‘s risk exposure in fiscal terms and for informing the future strategic actions taken once initial assessments are completed. Note that SRC costs, for purposes of this program, are generally assumed to account for all physical works related explicitly to seismic strengthening. Some buildings in the ACPD portfolio, especially older buildings with heritage registrations, are also likely to require extensive non-structural rehabilitation works that are not accounted for by the models proposed herein (e.g., new or rehabilitated roofing, cladding, windows, HVAC systems, carpeting, electrical wiring, ornamentation, etc.). $1,000
Δ%NBS due to seismic retrofit 0%
33%
67%
100% 711
$100
DSA = 8,644.30x-0.68 R² = 0.74
SRC unit cost (NZD/m2)
DSA unit cost (NZD/m2)
$900
$10
DSA = 8,328.85x-0.89 R² = 0.95
575
$600
SRC = 847.85x-0.07 358 $300
SRC = 573.93x-0.06
$0
$1 0
5000
10000
0
15000
Total floor area per building (m2) Auckland
2000
4000 6000 8000 10000 Total floor area per building (m2)
2 FEMA 156 RC (by m2) MartinJenkins/ACPD (by Δ%NBS)
Wellington
(a) Detailed seismic assessment (DSA)
12000
2 FEMA 156 URM (by m2) Power (FEMA 156 RC (by m2))
(b) Seismic retrofit construction (SRC)
Figure 8.3. Unit cost estimate models used for initial cost estimating (Note: 1.00 NZD ≈ 0.75 USD ≈ 0.50 GBP)
New Zealand consulting firm MartinJenkins (2012) developed SRC models which accounted inexactly for design age, structure type, and discrete %NBS thresholds desired after retrofit (specifically 34%NBS, 67% NBS, and 100%NBS). The MartinJenkins‘ SRC models were based on the results from a survey of a small group of New Zealand structural engineers. ACPD validated the accuracy and applicability of the MartinJenkins models with local structural engineers in Auckland as well as with relevant international literature (FEMA 1994) and then simplified the MartinJenkins models so as to represent generic buildings and account for discrete target improvement levels [Δ%NBS, see Figure 8.3(b)] for application to individual buildings. The FEMA (1994) approximate SRC unit costs were initially published 215
Seismic risk management of a large public facilities portfolio: a New Zealand case study
for the United States and accounted for structure type, approximate floor area, and regional seismicity. ACPD considered the FEMA SRC unit costs for a region of moderate seismicity and adjusted them to account for foreign exchange rates (1.00 NZD = 0.75 USD) and construction industry inflation (average of 4.66% per year per ENR 2014). The adjusted FEMA SRC models for RC and URM buildings are also shown in Figure 8.3(b). Typical SRC unit costs for most scenarios are assumed to be between 300 and 600 NZD/m 2, as indicated in Figure 8.3(b). In order to consider the fiscal liabilities associated with ACPD setting uniform acceptable risk thresholds across the entire portfolio, generic unit costs were considered in regard to the aforementioned predicted risk profiles (see Table 8.3). Any SRC work would be assumed to interfere with buildings occupants to the extent that they would need to be moved temporarily, so a unit cost of 5000 NZD per occupant was assumed from previous experience within ACPD. As noted previously, singular buildings or types of buildings often accommodate a great portion of building occupants. In the case of the scenario presented in Table 8.3 in which 630 assigned occupants are potentially affected by ACPD setting a portfolio-wide acceptable risk threshold of ―moderate‖ or better (> 34%NBS), 301 of those occupants reside in a single building where the only documented components that are potentially ―earthquake-prone‖ are isolated stairwell connections that are relatively inexpensive to retrofit. Other common vulnerable building components that by themselves are relatively inexpensive to repair include chimneys, parapets, and gable end walls, especially in URM buildings. Hence, the unit costs charted in Figure 8.3 and listed in Table 8.3 represent expected averages subject to very high variances for individual buildings. Table 8.3. Estimated generic seismic mitigation costs across the ACPD portfolio Acceptable risk threshold Moderate, > 34%NBS Low, > 67%NBS Compliant, > 100%NBS
# buildings Average floor # DSA unit below area per building occupants cost threshold affected (m2) affected (NZD/m2)
SRC unit cost (NZD/m2 by Δ%NBS)
Occupant Total cost move unit cost (mil NZD) (NZD/occ.)
211
617
630
27.35
358
5000
53
821
953
1094
18.59
575
5000
470
1720
1250
2972
14.60
711
5000
1,574
Note: 1.00 NZD ≈ 0.75 USD ≈ 0.50 GBP
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Seismic risk management of a large public facilities portfolio: a New Zealand case study
8.7. Strategies for ongoing seismic risk evaluation and mitigation efforts For purposes of budgeting for long-term expenses, ACPD has requested from Auckland Council executives and elected representatives the funding needed to commission DSAs and SRC for all buildings determined through the ISA process to be potentially high risk, resulting in the total value presented in Table 8.3 of approximately 50 million NZD. A portion of this total amount has been resourced and will be spent over the next twenty years with formal review every three years. Note that the total costs in Table 8.3 were tabulated assuming work was contracted for individual buildings, whereas savings are expected from packaging groups of similar buildings together. These savings can then be used to commission DSAs for important buildings determined through the ISA process to be potentially moderate risk. While a great deal will be learned about individual buildings through DSAs, ACPD will continue to seek improvement in its processes and knowledge database through investigation of soils types and by performing spatially-based vulnerability models to account for spatial distributions of buildings serving similar functions (e.g., post-disaster civil defence administration) considering that such buildings, if distant from each other, are unlikely to be rendered inoperable by the same earthquake. Furthermore, advanced awareness regarding the vulnerabilities of non-structural components and potential remedies (Cormier 2010) will be incorporated through Auckland Council‘s health and safety processes. Ongoing efforts to derive DSA and SRC costs from ACPD and peer projects will lead to the development of more sophisticated cost estimation models with greater predictive capabilities of variances due to specific building conditions. In the near-term, ACPD intends to control such variances by packaging buildings of similar structural configurations (e.g., URM buildings) and geographic locations together in requests for proposal to engineers, architects, and contractors so that exemplar assessments and retrofits can be utilised at lower unit costs and to ensure greater consistency of engineering evaluations and strengthening works.
8.8. Summary and conclusions The New Zealand government has enacted sweeping seismic risk mitigation mandates similar to but more comprehensive than those previously enacted or currently being considered by other governments around the world. ACPD has initiated its response to the mandate by identifying buildings most at risk to an earthquake in its large and varied portfolio through the use of a rapid building evaluation program strategically targeted to vulnerable building 217
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types with consequential attributes including service type, number of occupants, floor area, and geographic location. Specifically, buildings primarily constructed of URM and pre-1995 RC with assigned occupants and that provided regular functional services to the community were prioritised for evaluation and future potential retrofit work. ACPD has reviewed the policies and strategies of a number of peer portfolio owners in New Zealand to ensure that best-practice approaches are utilised in its seismic evaluation and retrofit prioritisation program and has adopted a number of such strategies. In contrast to what some peer owners have incorporated into their strategies and policies, however, decisions to commission further seismic assessment of and eventually retrofit or dispose/change-use of any individual building will not rest entirely or even largely on the assessed earthquake risk of that building. ACPD has and will likely continue to utilise a qualitative approach toward its strategic property portfolio review in order to account for numerous stakeholders and criteria such as service, community, and heritage values associated with its buildings wherein major decisions pertaining to the future use of such buildings will lie with the occupying service providers, relevant local boards, and regional heritage advisors. Were Auckland Council to eventually adopt a more quantitative high-level approach toward facilities management decisions (e.g., Langston 2013), the technical information being accrued by ACPD as part of its seismic evaluation program could readily be incorporated into weighted criteria pertaining to design standard, regulatory compliance, and structural condition. ACPD does currently quantify historic and predicted future life-cycle maintenance and capital expense costs for its buildings, and the cost estimate models proposed herein for SRC work are provisionally being implemented into its capital renewals planning.
8.9. Acknowledgements The authors wish to acknowledge the financial support provided by the Auckland Council Property Department (ACPD) and the information provided by the Auckland Council departments of Building Control, Civil Defence and Emergency Management (CDEM), and Health & Safety. Information from building evaluations carried out by local engineering firms and by former and current students at the University of Auckland – including Jade Littleton, Esther Smith, Rohit Pantham, Carishma Yeleswaram, Chris Luttrell, Kirby McClean, Rui Wang, Cale Wood, and Yuchen Song – was referenced herein.
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8.10. References Alani, A.M., and Khosrowshahi, F. (2007). ―Development of an effective methodology for assessment, repair and maintenance of the earthquake damaged buildings." Facilities, 25(1/2), 32–47, 10.1108/02632770710716920. ASCE (American Society of Civil Engineers). (2014). ―Seismic evaluation and retrofit of existing buildings.‖ ASCE 41-13, Reston, Virginia. ATC (Applied Technology Council). (1985). ―Earthquake damage evaluation data for California.‖ ATC-13, Redwood City, California. ATC (Applied Technology Council). (1989). ―Procedures for post-earthquake safety evaluation of buildings.‖ ATC-20, Redwood City, California. ATC (Applied Technology Council). (2000). ―Database on the performance of structures near strong-motion recordings: 1994 Northridge, California, earthquake.‖ ATC-38, Redwood City, California. Au, E., Lomax, W., Walker, A., Banks, G., and Haverland, G. (2013). ―A discussion on the differences between New Zealand‘s philosophy for the seismic design of new buildings and seismic assessment of existing buildings and the issues that arise.‖ Proceedings of the New Zealand Society for Earthquake Engineering Conference, 26–28 April, Wellington, New Zealand. Auckland Council. (2011). Earthquake-prone, dangerous & insanitary buildings policy (2011–2016), Auckland, New Zealand. Brown, J., Walsh, K., and Cummuskey, P. (2014). ―The four R‘s – reduce risk, raise resilience: Local authority priorities and the Auckland perspective on engineering requirements for heritage buildings.‖ 4th Australasian Engineering Heritage Conference, 24–26 November, Christchurch, New Zealand. City of Los Angeles. (1949). Los Angeles City Building Code and Other Ordinances, Department of Building and Safety, Los Angeles, California. City of Los Angeles. (1985). "Division 88: earthquake hazard reduction in unreinforced masonry buildings." City of Los Angeles Building Code, Los Angeles, California. City of Los Angeles. (2014). Resilience by Design. Mayor‘s Seismic Safety Task Force, City of Los Angeles, California, (23 February 2015). City of Portland. (2004). Chapter 24.85: seismic design requirements for existing buildings, City Code and Charter, City of Portland, Oregon.
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City of San Francisco. (1993). Earthquake safety programs: community safety element of the San Francisco master plan, Department of City Planning, City of San Francisco, California. (28 March 2015). City and County of San Francisco. (2013). ―Mandatory seismic retrofit program – woodframe buildings.‖ San Francisco Building Code, City and County of San Francisco, California, (28 March 2015). City of Seattle. (2009). "Chapter 34 - existing buildings and structures.‖ Seattle Building Code, City of Seattle, Washington. City of Seattle. (2014). ―Recommendations for an unreinforced masonry policy.‖ URM Policy Committee, Department of Planning and Development, City of Seattle, Washington. City of Vancouver. (2012). Vancouver building bylaw 9419, City of Vancouver, British Columbia, Canada. Cooper, M., Carter, R., and Fenwick, R. (2012). Canterbury Earthquakes Royal Commission final report, volumes 1–7, Royal Commission of Inquiry, Christchurch, New Zealand, . Cormier, S. (2010). ―Integrating seismic preparedness into facilities capital planning.‖ Facilities Management Journal Magazine, Houston, Texas. (15 January 2015). CSA (Canadian Standards Association). (2014). ―Seismic risk reduction of operational and functional components (OFCs) of buildings.‖ S832-14, Mississauga, Ontario, Canada. Edbrooke, S.W. (compiler) (2001). Geology of the Auckland Area, Institute of Geological and Nuclear Sciences, Lower Hutt, New Zealand. ENR (Engineering News-Record). (2014), ―Construction economics.‖ New York City, New York, (5 January 2015). FEMA (Federal Emergency Management Agency). (1994). ―Typical costs for seismic rehabilitation of existing buildings.‖ FEMA 156, Washington, D.C. FEMA (Federal Emergency Management Agency). (2002). ―Rapid visual screening of buildings for potential seismic hazards.” FEMA 154, Washington, D.C.
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FEMA (Federal Emergency Management Agency). (2009). ―Unreinforced masonry buildings and earthquakes: Developing successful risk reduction programs.‖ FEMA P-774, Washington, D.C. GNS (Geological and Nuclear Sciences Ltd). (2010). ―RiskScape user manual, Ver. 0.2.30.‖ GNS Science, Lower Hutt, New Zealand. Kenny, J.A., Lindsay, J.M., and Howe, T.M. (2011). ―Large-scale faulting in the Auckland region.‖ Institute of Earth Science and Engineering (IESE), Auckland, New Zealand. Langston, C. (2013). ―The impact of criterion weights in facilities management decision making: An Australian case study.‖ Facilities, 31(7/8), 270–289, 10.1108/02632771311317448. Lin, R., and Xia, R. (2014). ―LA Mayor Garcetti set to unveil earthquake safety plan.‖ LA Times, (7 December 2014). Linstrom, D., and Sharpe, R.D. (2013). ―Acting on the seismic assessment of a large portfolio.‖ Proceedings of the New Zealand Society for Earthquake Engineering Conference, Wellington, New Zealand. MacRae, G., Clifton, C., and Megget, L. (2011). ―Review of NZ building codes of practice.‖ Royal Commission of Inquiry, Christchurch, New Zealand. MartinJenkins. (2012). ―Indicative CBA model for earthquake prone building review: Summary of methodology and results.‖ Ministry of Business, Innovation, and Employment, Wellington, New Zealand. Monitor Auckland. (2012). ―Gross domestic product (GDP) and average annual change.‖ Auckland Council, (12 December 2012). Moon, L., Dizhur, D., Senaldi, I., Derakhshan, H., Griffith, M., Magenes, G., and Ingham, J. (2014). ―The demise of the URM building stock in Christchurch during the 2010–2011 Canterbury earthquake sequence.‖ Earthquake Spectra, 30(1), 253–276. Newman, P. (1976). ―San Francisco‘s Parapet Ordinance.‖ Foundation for San Francisco's Architectural Heritage, American Institute of Architects Northern California Chapter, San Francisco, California. New Zealand Parliament. (1992). Health and Safety in Employment Act 1992, Department of Labour, New Zealand Government, Wellington, New Zealand. New Zealand Parliament. (1993), Historic Places Act, Ministry for Culture and Heritage, New Zealand Parliament, Wellington, New Zealand.
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New Zealand Parliament. (2004). Building Act 2004, Department of Building and Housing, Ministry of Economic Development, New Zealand Government, Wellington, New Zealand. New Zealand Parliament. (2005). Building, (specified systems, change the use, and earthquake-prone buildings) regulations, Department of Building and Housing, Ministry of Economic Development, New Zealand Government, Wellington, New Zealand. New Zealand Parliament. (2013). Buildings (earthquake-prone buildings) Amendment Bill, Ministry of Business, Innovation, and Employment (MBIE), New Zealand Parliament, Wellington, New Zealand. NZS (Standards New Zealand). (2002). ―Structural design actions, Part 0: General principles.‖ NZS 1170.0:2002, Incorporated Amendments 1–5. Australian Standards (AS) and Standards New Zealand (NZS) Joint Technical Committee BD-006, Wellington, New Zealand. NZS (Standards New Zealand). (2004). ―Structural design actions, Part 5: Earthquake actions – New Zealand.‖ NZS 1170.5:2004, Standards New Zealand Technical Committee BD006-04-11, Wellington, New Zealand. NZSEE (New Zealand Society for Earthquake Engineering). (2014). Assessment and improvement of the structural performance of buildings in earthquakes, recommendations of a NZSEE project technical group, Incorporated Corrigenda No. 3, Section 3, Initial seismic assessment, New Zealand Society for Earthquake Engineering, Wellington, New Zealand. Paxton, B., Turner, F., Elwood, K., and Ingham, J. (2015). ―URM bearing wall building seismic risk mitigation on the west coast of the United States: a review of policies and practices.‖ Bulletin of the New Zealand Society for Earthquake Engineering, 48(1), 31– 40. Ploeger, S., Sawada, M., Elsabbagh, A., Saatcioglu, M., Nastev, M., and Rosetti, E. (2015). ―Urban RAT: New tool for virtual and site-specific mobile rapid data collection for seismic risk assessment.‖ Journal of Computing in Civil Engineering, 10.1061/(ASCE)CP.1943-5487.0000472 , 04015006. PMCoE (Property Management Centre of Expertise). (2013). Undertaking Seismic Risk Assessments for Buildings Occupied by Government Agencies, Wellington, New Zealand. Sheppard, J., and Brunsdon, D. (2013). ―Earthquake assessment of school buildings in New Zealand: issues and challenges.‖ Proceedings of the New Zealand Society for Earthquake Engineering Conference, Wellington, New Zealand. Statistics New Zealand. (2013). ―Infoshare; Group: Population estimates - DPE; Table: Estimated resident population for territorial authority areas, at 30 June (1996+) (AnnualJun).‖ (7 August 2013). 222
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Tokyo Metropolitan Government. (2011). ―Ordinance to promote the earthquake resistance of emergency transportation roadside buildings in Tokyo.‖ Tokyo Ordinance No. 36, Tokyo, Japan. Turner, S. (2011). ―Town hall and municipal office building – earthquake prone buildings: Health and safety issues.‖ Letter from Samantha Turner, Simpson Grierson, to Ruth Hamilton, Wellington City Council. 14 July 2011. Walsh, K., Dizhur, D., Almesfer, N., Cummuskey, P., Cousins, J., Derakhshan, H., Griffith, M., and Ingham, J. (2014a). ―Geometric characterisation and out-of-plane seismic stability of low-rise unreinforced brick masonry buildings in Auckland, New Zealand.‖ Bulletin of the New Zealand Society for Earthquake Engineering, 47(2), 139–156. Walsh, K., Elwood, K., and Ingham, J. (2014b). "Seismic considerations for the Art Deco interwar reinforced-concrete buildings of Napier, New Zealand." Natural Hazards Review, 16(4), 04014035. WorkSafe New Zealand. (2013). ―Position statement – dealing with earthquake-related hazards: Information for employers and owners of workplace buildings.‖ Government of New Zealand, Wellington, New Zealand.
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Chapter 9. Summary, conclusions, and recommendations Reporting on the causes of building failures in the Christchurch earthquake, the Canterbury Earthquakes Royal Commission of Inquiry (Cooper et al. 2012) identified two building structure types as being especially vulnerable to earthquakes: unreinforced masonry (URM) buildings and reinforced concrete (RC) buildings with non-ductile or low-ductile components. Addressing the need for structural engineers and technical authorities to expand the knowledge and implementation of state-of-the-art design and assessment techniques for such buildings, the Royal Commission made the following recommendations:
Structural engineers should assess the validity of basic assumptions made in their analyses;
The Ministry of Business, Innovation and Employment [MBIE] should review the New Zealand Society [for] Earthquake Engineering [NZSEE] Recommendations entitled Assessment and Improvement of the Structural Performance of Buildings in Earthquakes [NZSEE 2006] and, in conjunction with engineering practitioners, establish appropriate practice standards or methods for evaluating existing buildings;
Territorial authorities and subject matter experts should share information and research on the assessment of, and seismic retrofit techniques for, different building types; [and]
The universities of Auckland and Canterbury should pursue ways of increasing the structural and geotechnical knowledge of civil engineers entering the profession.
In response to the Royal Commission recommendations as well as specific requests from the New Zealand building industry, the primary research objectives of the various projects described herein were to provide state-of-the-art knowledge on building typological data, experimentally measured behaviour, and seismic assessment methods for URM and RC building components, and to provide appropriate suggestions for implementing assessment and retrofit strategies into portfolio management programs. In the process, the validity of several assumptions regarding the seismic vulnerability of certain building components has been considered and tested, and subsequently, some of the technical recommendations made in this manuscript have been implemented into or referenced in proposed future updates of NZSEE (2006) and ASCE (2014) such that the most appropriate methods for evaluating
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existing buildings are publicly disseminated to students and practitioners. Specific findings pertaining to the various primary objectives of the research program documented herein are summarised in the following sub-sections.
9.1. Identification and provisional vulnerability assessment of URM and RC buildings and building components In their final report (Cooper et al. 2012), the Royal Commission made several recommendations in regard to the identification of vulnerabilities and risk awareness, recommending the following:
Territorial authorities should be required to maintain and publish a schedule of earthquake-prone buildings in their districts; [and]
The engineering and scientific communities should do more to communicate to the public the risk buildings pose in earthquakes, what an assessment of building strength means, and the likelihood of an earthquake.
Typological findings and provisional vulnerability assessments for URM and RC buildings and building components were addressed in Chapter 2, Chapter 3, and Chapter 4 of this manuscript. The research reported on in the aforementioned chapters either contributed directly to or evaluated in greater detail schedules of potentially earthquake-prone buildings in Auckland and Napier, New Zealand. As noted in the aforementioned chapters, rapid and qualitative seismic assessments such as the initial evaluation procedure (IEP) are useful to quickly identifying and categorising potentially vulnerable buildings within a large building stock. The studies documented herein were intended to demonstrate the utility of typological investigations and protocols for extrapolating data while accounting for selection biases. As part of an inspection program targeting buildings likely to be most vulnerable to earthquakes, thousands of buildings in the Auckland region were assessed with varying amounts of typological data recorded including lateral load resisting system (LLRS) construction type, number of storeys, and time period of construction. Engineers, risk modellers, and regulators in other cities can consider the typological studies reported herein as case studies for how survey data may be collected and extrapolated to account for typological information not yet recorded. However, such preliminary assessments generally do not result in descriptions or quantifications of likely building failure mechanisms 226
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(e.g., damage versus collapse potential), such that the public is left unaware of what ―building strength‖ actually means in regard to the collapse potential of particular buildings or types of buildings. Furthermore, the public is often uninformed regarding the relationship amongst average earthquake return periods, earthquake-induced ground motion intensity, and building component collapse risks. Hence, displacement-based and collapse-oriented seismic vulnerability evaluations were carried out for URM building walls in Auckland as presented in Chapter 3 and for RC moment resisting frames in Auckland and Napier as presented in Chapter 2 and Chapter 4, respectively, with the goal of communicating more clearly structural collapse potential to the public and appropriately directing seismic risk-mitigation strategies that can be planned and enacted efficiently and effectively. In regard to buildings constructed entirely or mostly of load-bearing URM walls, the research documented herein resulted in the following conclusions:
URM load-bearing walls were estimated to constitute the primary LLRS for just over 5% of the approximately 20,000 commercial buildings in the Auckland region. Over 90% of these buildings were constructed 1–3 storeys above grade, and most were constructed with clay brick masonry and prior to 1935 (Chapter 3);
Approximately 20% of the clay brick URM buildings in Auckland that are 1–3 storeys in height and unretrofitted would be expected to experience at least partial out-of-plane (OOP) collapse when subjected to the peak ground acceleration intensities associated with the National Seismic Hazard Model 2010 (Christophersen et al. 2011; Stirling et al. 2012) return period of 1 in 500 years (Chapter 3); and
An earthquake originating from the Wairoa North fault in South Auckland causing 33%NBS demands in the Auckland CBD on shallow soil sites would be expected to cause OOP wall collapse of 15% of low-rise, unretrofitted clay brick URM buildings in Auckland (Chapter 3).
In regard to buildings constructed entirely or mostly of RC moment resisting frames, the research documented herein resulted in the following conclusions and recommendations:
RC moment resisting frames were estimated to constitute the primary LLRS for over 40% of the approximately 20,000 commercial buildings in the Auckland region, and
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approximately one in four of these buildings was identified as having infill walls (Chapter 2);
Of a sample of 25 mid-rise buildings constructed of RC moment resisting frames which were granted building consents between 1982 and 1995 in Auckland, approximately half of the buildings also had shear walls. All of the sampled buildings had precast RC floor systems of some type, with hollowcore slabs being the most prominent. The average minimum combined structural footprint ratio (ratio of the sum of RC column and in-plane shear wall cross-sectional areas to the total building footprint area in the direction of lateral loading) for these buildings was approximately 1% (Chapter 2);
Of the existing 125 Art Deco buildings in Napier that were identified, 84% of the buildings were constructed or reconstructed soon after the 1931 Hawke‘s Bay earthquake (1931–1936). The prototypical Napier Art Deco building is comprised of an RC two-way moment resisting frame, is two storeys in height, is a row style building relative to its neighbours, is formally Art Deco in architectural style, and was designed by one of five firms. Fewer than 5% of all Art Deco buildings surveyed were determined to have potential plan or vertical irregularities (expected to cause significantly detrimental eccentric deformations when subjected to lateral load) or potentially shortened columns (expected to result in brittle column behaviour). Furthermore, it was determined that only 12% of Napier Art Deco buildings had elevated potential for pounding because of excessive height differences and/or offset storey alignment between neighbouring buildings (Chapter 4);
The prototypical Napier interwar building constructed with RC moment resisting frames has a structural footprint ratio of approximately 1.9%, which is a relatively high value that can be associated with successful performance in historic earthquakes in New Zealand and internationally (Chapter 4);
Coupled with the provisional vulnerability assessment findings, the observed performance of low-rise, ostensibly brittle RC buildings in the 1931 Hawke‘s Bay earthquake, the 2011 Christchurch earthquake, and other historic earthquakes, both in New Zealand and elsewhere, lends credence to the conclusion that most buildings
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with RC moment resisting frames in New Zealand are generally underrated in simple, force-based seismic assessments (Chapter 4); and
Common potential vulnerabilities identified among the Art Deco buildings that should be closely considered include non-structural falling hazards (namely slender, inadequately reinforced parapets and URM infill walls, especially atop taller buildings) and pounding potential with neighbouring buildings with offset building or storey heights (Chapter 4).
9.2. Testing and assessment of the out-of-plane performance of URM walls URM construction is prominent in the New Zealand building population in the form of loadbearing, partition, and infill walls (see Chapter 2 and Chapter 3). In particular, significant outof-plane (OOP) failures of URM walls can often occur during moderate and severe earthquake shaking (Ingham and Griffith 2011; Moon et al. 2014), and such walls are often identified in structural engineering assessments as being amongst the most vulnerable elements to OOP loads, especially earthquakes. Due to the widespread failures in Christchurch of URM buildings, in particular, the Royal Commission made specific recommendations pertaining to URM buildings as follows:
The detailed assessment of unreinforced masonry buildings that are earthquake-prone should take into account the potential need to… ensure adequate connection between all structural elements of the building so that it responds as a cohesive unit; [and]
The legislation should be further amended to require that, in the case of unreinforced masonry buildings, the out-of-plane resistance of… parapets… and external walls to lateral forces shall be strengthened.
In response to the recommendations of the Royal Commission as well as the stated limitations of earthquake loss models to predict OOP collapses of URM components (Cousins et al. 2014), analytical and experimental programs were undertaken as documented in Chapter 3, 0, and 0. The research documented herein resulted in the following conclusions and recommendations:
The installation of lateral restraints may significantly raise the capacities of buildings at most considered levels of ground motion intensity (Chapter 3);
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The estimated percentage of low-rise clay brick URM buildings experiencing out-ofplane collapses in the Wairoa North fault 33%NBS earthquake scenario drops from 15% for unretrofitted buildings to 4% if a comprehensive roof and parapet restraint program were to be instituted, and it drops to 0.4% if adequate lateral restraints are added at the parapet, roof and floor levels (Chapter 3);
A capacity limit at high ground motion intensities is reached by the diaphragm restraint retrofit solutions considered in this study, particularly when lower-bound ―characteristic‖ performance is assumed, as walls between restraints at each storey will still fail out of plane at high lateral load demands. In order to more effectively improve buildings to sustain high levels of intensity (and achieve acceptable levels of %NBS), more invasive retrofit procedures may need to be considered (Chapter 3);
The consideration of two-way flexure in addition to one-way vertical flexure may aid in improving estimated URM capacity/demand ratios (Chapter 3);
URM walls which are confined or bounded by relatively rigid elements, such as steel or RC frames with URM infill walls, may form an arching mechanism while deforming OOP which will likely increase the OOP capacity of vertically-spanning infill walls as compared to URM walls without OOP arching mechanisms. However, buildings in Australasia with load-bearing URM walls typically have timber diaphragms which have been experimentally shown to provide little to no arching action to URM walls (0);
Displacement-based OOP performance criteria (with appropriate capacity-reduction factors) should generally be considered for URM walls without arching action, and force-based performance criteria should be considered for URM infill walls with arching action (0);
URM cavity walls without arching action at all storey levels and walls with arching action at higher storey levels are susceptible to OOP strength exceedance when subjected to design basis earthquake (DBE) demands in regions of either moderate seismicity (e.g., Auckland) or high seismicity (e.g., Hastings) (0);
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Existing OOP assessment methods may be viable for assessing cavity walls in vertical flexure provided that the equivalent solid wall thickness is determined firstly (0 and 0);
Cavity tie retrofits with adequate spacing, as well as adequate compressive and shear stiffness, can greatly improve the OOP capacity of URM cavity walls, especially for infill walls experiencing OOP arching action (0 and 0);
Provisional, empirically-based relationships were proposed in an attempt to predict the OOP performance of URM cavity walls with various cavity tie conditions (0); and
In assessing URM infill walls for OOP strength, the engineer may wish to consider the effects of the thrust forces resulting from the infill OOP arching action in regard to its effects on the bounding frame elements. To that end, an existing model was amended so as to provide engineers with a complete set of equations for predicting the thrust force based on knowledge of only masonry infill material strengths, infill wall geometry, and basic bounding frame element characteristics (0).
9.3. Testing and assessment of the performance of RC frames In addition to URM buildings, the Royal Commission of Inquiry (Cooper et al. 2012) identified RC moment resisting frame building structure types as being especially vulnerable to earthquakes, being a structure type that was responsible for 133 fatalities during the February 2011 Christchurch earthquake due to the collapses of the Pyne Gould Corporation (PGC) building and the Canterbury Television (CTV) building. The Royal Commission made the following recommendations:
In the assessment of buildings for their potential seismic performance…
the
individual structural elements should be examined to see if they have capacity to resist seismic and gravity load actions in an acceptably ductile manner… [and] while the initial lateral strength of a building may be acceptable, critical non-ductile weak links in load paths may result in rapid degradation in strength during an earthquake. It is essential to identify these characteristics and allow for this degradation in assessing potential seismic performance. The ability of a building to deform in a ductile mode and sustain its lateral strength is more important than its initial lateral strength; [and] 231
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Arising from our study of the CTV building, it is important that the following, in particular, should be examined: the beam-column joint details… [and] the level of confinement of columns to ensure that they have adequate ductility to sustain the maximum inter-storey drifts that may be induced in a major earthquake.
In response to the recommendations of the Royal Commission as well as the needs of organisations such as the Auckland Council and the Napier Art Deco Trust, analytical and experimental programs were undertaken as documented in Chapter 2, Chapter 4, 0, and Appendix E. The research documented herein resulted in the following conclusions and recommendations:
Of a sample of 23 mid-rise buildings constructed of RC moment resisting frames which were granted building consents between 1982 and 1995 in Auckland, 14 were identified as containing at least one potentially non-ductile RC column (i.e., likely to experience a shear-controlled failure mechanism under lateral loading with a corresponding predicted displacement ductility capacity less than 1.0). Estimated ratios of shear demand at plastic hinging to nominal shear capacity, Vp / Vn , for the worst-case column in each of the 23 buildings ranged between 0.56 and 2.41. Design demands must also be accurately estimated before RC columns can be considered ―earthquake-prone,‖ but structural footprint ratios can be used to help prioritise buildings for further detailed assessment (Chapter 2);
The expected failure condition in the prototypical Art Deco RC rectangular column is expected to be flexure preceding shear cracking, as was observed in similar buildings damaged by the 2011 Christchurch earthquake (Chapter 4);
In lieu of materials testing, assumed material strengths for use in assessing Art Deco buildings should generally be approximately 245–270 MPa for the tensile yielding of steel reinforcement and 14–21 MPa for the ultimate compressive strength of concrete (Chapter 4);
New Zealand engineers performing seismic assessments of Art Deco RC buildings should reduce the applied earthquake demands assuming a level of structural displacement ductility capacity of at least 1.75 (to be further considered in future research efforts) unless a critical weakness is identified in the RC frame geometry or detailing (Chapter 4); 232
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Potential vulnerabilities identified among the Art Deco columns that should be closely considered during assessment include splice or anchorage failure of smooth reinforcement bars, premature buckling of longitudinal reinforcement in columns, and column shear strength degradation at high ductility demands (Chapter 4 and Appendix E);
Infill walls may have contributed greatly to the successful performance of interwar RC buildings in previous earthquakes and should be accounted for in assessments where present. The case study as presented in Appendix E directs the engineer on how to account for the potentially detrimental effects caused by infill walls, including the torsional modal reactions caused by eccentrically placed infill walls (by identifying the increased displacement demands on columns located far from the centre of eccentricity in the model) and ―short column‖ behaviour caused by partial-height infill (by reducing the column clear-height for pushover capacity modelling);
The experimentally tested 1980s-era H-frame precast RC beams with intended ―shearductile‖ detailing exhibited less displacement ductility capacity and equivalent viscous damping capacity than the more conventionally detailed beams designed for flexural hinge formations. Nonetheless, the tested non-retrofitted H-frame was determined to have sufficient strength and displacement capacity to meet its contemporary design demands, and it did not appear to be affected by low-cycle fatigue in the steel reinforcement (0);
Deformation and damage in the 1980s-era H-frame beams was due largely to the development of shear-sliding mechanisms located in the regions near the diagonallyaligned beam reinforcement as previously observed in testing of precast RC beams with similar reinforcement details and predicted by analysis using a strut-and-tie model (0);
The experimentally tested 1980s-era retrofitted H-frame shear-ductile beam was able to be repaired and retrofitted to an enhanced strength capacity without reducing the displacement capacity as compared to its non-retrofitted counterpart. However, the utilised retrofit technique did not prevent shear-sliding mechanisms from occurring near midspan, contrary to the retrofit design intent (0);
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The results of previous experimental testing as well as the testing reported herein on 1980s-era RC frame components indicated that the column and beam-column joint were very stiff relative to the beams and contributed relatively little to the ductile deformation mechanisms of the frame. These experimental findings were consistent with the design intentions for contemporary beam-column joints to both ensure the appropriate development length of reinforcement through the beam-column joints so as to limit bond deterioration due to cyclic loads on beams on opposite sides of the joint region, and to size and detail the columns so as to ensure their higher stiffness and strength relative to the beams (0); and
The anticipated inter-storey shear yield drift, yield strength, and equivalent damping capacity of the more conventionally detailed 1980s-era beams were accurately predicted using existing empirically-based or analytical procedures (0).
9.4. Portfolio management considering earthquake risks and regulations In their final report (Cooper et al. 2012), the Royal Commission recommended that efforts be made to inform industry participants, such as property managers, regarding seismic risks and how such risks could be addressed. In regard to the identification of vulnerabilities and risk awareness, the Royal Commission recommended the following:
Industry participants, such as… property managers, should ensure that they are aware of earthquake risks and the requirements for earthquake-prone buildings in undertaking their roles, and in their advice to building owners; [and]
The Ministry of Business, Innovation and Employment [MBIE] should support industry participants’ awareness of earthquake risks and the requirements for earthquake-prone buildings through provision of information and education.
In response to the recommendations of the Royal Commission as well as national legislation, a case study of seismic risk management for a large building portfolio was documented in 0 detailing the approach taken by the Auckland Council Property Department (ACPD), which manages the public facilities portfolio for the largest local administrative region in New Zealand in both population and landmass. Identifying those buildings most at risk to an earthquake in a large and varied portfolio warranted the use of a rapid building evaluation program supplemented by strategically chosen detailed assessments. ACPD considers its 234
Summary, conclusions, and recommendations
―risk point‖ as the product of three components, being vulnerability, hazard, and consequence. To that end, buildings were initially prioritised for inspection using the best available information regarding building location, number of assigned occupants, functional type, design age (or, alternatively, construction age), structure type, number of storeys above grade, and floor area. For predictions of the entire portfolio‘s risk profile, the results of the completed evaluations were marginally weighted in accordance with known distributions of structure type and age of construction to account for the evaluation biases toward buildings most likely to be at risk. Based on the estimated distributions of buildings across the portfolio by seismic risk category, provisional costs estimations were made in order for ACPD to budget for future detailed seismic assessments and retrofits. ACPD intends to control such variances by packaging buildings of similar structural configurations (e.g., URM buildings) and geographic locations together in requests for proposal to engineers, architects, and contractors so that exemplar assessments and retrofits can be utilised at lower unit costs and to ensure greater consistency of engineering evaluations and strengthening works. Advanced awareness regarding the vulnerabilities of non-structural components and potential remedies was recommended to be incorporated through Auckland Council‘s health and safety processes.
9.5. Ongoing investigations and proposed research needs In regard to typological vulnerability studies, other data relevant to the taxonomical classification systems noted in Chapter 2 and Chapter 3 is being accrued by the Auckland Council. Information pertaining to building position within a block, shape of the building plan, structural irregularities, and foundation system are being accrued through related structural inspections, and this information is accounted for in to the GEM (2013) taxonomy. Information pertaining to exterior wall cladding material, roof material and geometry, and floor system is also being accrued, and this information is accounted for in both the GEM and RiskScape (GNS 2010) taxonomies. Consequence-related information accounted for in RiskScape, such as such as condition, floor area, footprint area, number of potential occupants, and replacement costs, is available through other sources, including real estate valuation agencies and fire departments. In regard to URM wall testing and assessment, further work on URM out-of-plane assessments will involve performing further spatially-oriented analyses to include additional buildings expected to be documented in more rural areas of the Auckland region, as noted in 235
Summary, conclusions, and recommendations
Chapter 3. An extrapolation of these results to the URM building population across New Zealand is also intended in order to answer the following questions:
If a nationwide effort were instituted to seismically restrain all URM parapets, what overall performance improvement would be expected?
If a nationwide effort were instituted to provide wall-diaphragm anchorages to all URM buildings across New Zealand, then what overall performance improvement would be expected?
As implied in 0 and 0, additional predictive methods for OOP assessment may be considered in regard to the equivalent solid wall thickness for retrofitted cavity walls. Furthermore, since a limited range of material properties, component geometries, and retrofit cavity tie scenarios were tested in this experimental program for validation, additional testing of URM cavity walls is warranted. As implied in 0, measuring the thrust force on the bounding frame due to OOP arching action of the infill wall directly during experimental testing would be an improvement relative to deriving the thrust force from measured deflections and material properties. In regard RC frames testing and assessment and as noted in Chapter 4, the researchers intend to perform and report on the results of a detailed assessment of a representative Art Deco building with common parametric variations (e.g., differences in infill wall locations and roof diaphragm types). The results of this latter study could also be incorporated into fragility curve functions particular to Hawke‘s Bay‘s Art Deco building stock to enhance the accuracy of New Zealand‘s seismic hazard models and either validate or improve upon previous work done internationally in this realm. Further experimental study on the deformation capacity of columns with smooth, round longitudinal reinforcement (including in situ testing, if possible) would help refine the estimation of ductility capacities for these buildings. In regard to seismic risk awareness and risk-mitigation strategies for which a case study was detailed in 0, large building portfolio owners should continue to seek improvement in processes and hazard identification through investigation of soils types and by performing spatially-based vulnerability and risk models. Ongoing efforts to derive seismic retrofit consulting and construction costs from peer projects will lead to the development of more sophisticated cost estimation models with greater predictive capabilities of variances due to specific building conditions. Finally, seismic mitigation mandates, such as the one currently 236
Summary, conclusions, and recommendations
enforced in New Zealand, are often perceived as being in conflict with other social objectives and legislation, such as that pertaining to heritage preservation. Auckland Council‘s consideration of heritage buildings and earthquakes is addressed in other literature (Brown et al. 2014), and the value of heritage (e.g., willingness to pay) from tenants and community stakeholders should be accounted for in benefit-cost analyses as part of the seismic retrofit decision-making process.
9.6. References Brown, J., Walsh, K., and Cummuskey, P. (2014). ―The four R‘s – reduce risk, raise resilience: Local authority priorities and the Auckland perspective on engineering requirements for heritage buildings.‖ 4th Australasian Engineering Heritage Conference, Christchurch, New Zealand. Christophersen, A., Gerstenberger, M., Rhoades, D., Stirling, M. (2011). ―Quantifying the effect of declustering on probabilistic seismic hazard.‖ Proceedings of the Ninth Pacific Conference on Earthquake Engineering, 14–16 April, Auckland, New Zealand. Cooper, M., Carter, R., and Fenwick, R. (2012). Canterbury Earthquakes Royal Commission final report, volumes 1–7, Royal Commission of Inquiry, Christchurch, New Zealand. http://canterbury.royalcommission.govt.nz Cousins, W.J., Nayyerloo, M., and Delinge, N.I. (2014). ―Estimated damage and casualties from earthquakes affecting Auckland.‖ GNS Science Consultancy Report 2013/324, Institute of Geological and Nuclear Sciences (GNS), Lower Hutt, New Zealand. GEM (Global Earthquake Model). (2013). ―GEM building taxonomy v2.0: An overview.‖ (25 December 2013). GNS (Geological and Nuclear Sciences Ltd). (2010). ―RiskScape user manual, Ver. 0.2.30.‖ GNS Science, Lower Hutt, New Zealand. Ingham, J., and Griffith, M. (2011). ―Performance of unreinforced masonry buildings during the 2010 Darfield (Christchurch, NZ) earthquake.‖ Australian Journal of Structural Engineering, 11(3), 207–224. Moon, L., Dizhur, D., Senaldi, I., Derakhshan, H., Griffith, M., Magenes, G., and Ingham, J. (2014). ―The demise of the URM building stock in Christchurch during the 2010–2011 Canterbury earthquake sequence.‖ Earthquake Spectra, 30(1), 253–276. NZSEE (New Zealand Society for Earthquake Engineering). (2006). Assessment and improvement of the structural performance of buildings in earthquakes, recommendations of a NZSEE study group on earthquake risk of buildings, Incorporated Corrigenda No. 1 & 2, New Zealand Society for Earthquake Engineering, Wellington, New Zealand. 237
Summary, conclusions, and recommendations
Stirling, M., McVerry, G., Gerstenberger, M., Litchfield, N., Van Dissen, R., Berryman, K., Barnes, P., Wallace, L., Villamor, P., Langridge, R., Lamarche, G., Nodder, S., Reyners, M., Bradley, B., Rhoades, D., Smith, W., Nicol, A., Pettinga, J., Clark, K., and Jacobs, K. (2012). ―National Seismic Hazard Model for New Zealand: 2010 Update.‖ Bulletin of the Seismological Society of America, 102(4), 1514–1542.
238
Appendix A. Additional information pertaining to commercial building typological categories in Auckland, New Zealand
Appendix A. Additional information pertaining to commercial building typological categories in Auckland, New Zealand The tables in this appendix provide typological information (both documented and estimated) additional to that reported in Chapter 2 for Auckland commercial buildings. Please refer to Chapter
2
for
complete
references
to
239
the
literature
cited
in
this
appendix.
Appendix A. Additional information pertaining to commercial building typological categories in Auckland, New Zealand
Table A.1. Documented primary lateral load-resisting system (LLRS) material and structural system attributes Auckland Council notation
GEM (2013)
Structure type category
Documented # bldgs
Material of the LLRS system level 1
Concrete shear wall*
65
RCF* RCF with block infill* RCF with brick Infill
1065 119 147
RCF with masonry shear wall*
18
Steel frame* Steel frame with brick Steel frame with concrete block* Steel frame with RCF* Timber* Timber with blockwall perimeter* Timber with brick Timber with brick cladding* Timber with concrete block* Timber with steel frame*
309 1 2 1 1362 2 1 3 1 2
Other with steel tanks
4
URBM
1073
Stone masonry (URSM)
17
Masonry shear wall
480
MR (Masonry, reinforced)
Unknown Unknown with brick cladding
15213 0
MAT99 (Unknown material)
Material of the LLRS system level 2
LLRS Level 1 LWAL (Wall)
CR (Concrete, reinforced) or SRC (Concrete, composite with steel section)
CIP (Cast-in-place concrete) or PC (Precast concrete) or CIPPS (Cast-in-place prestressed concrete) or PCPS (Precast prestressed concrete)
S (Steel)
SR (Hot-rolled steel members)
W (Wood)
WLI (Light wood members)
MATO (Other material)
-
MUR (Masonry, unreinforced)
CLBRS (Fired clay solid bricks) or CLBRH (Fired clay hollow bricks) and/or RCB (Reinforced concrete bands) STRUB (Rubble (field stone) or semi-dressed stone) or STDRE (Dressed stone) CBH (Concrete blocks, hollow) and RS (Steelreinforced) -
LFM (Moment frame)** LFINF (Infilled frame) [1/2] LFINF (Infilled frame) [2/2] LDUAL (Dual frame-wall system)** LFM (Moment frame) LFINF (Infilled frame) [1/2] LFINF (Infilled frame) [2/2] LH (Hybrid LLRS) LWAL (Wall) [1/2] LFINF (Infilled frame) [1/2] LFINF (Infilled frame) [2/2] LWAL (Wall) [2/2] LDUAL (Dual frame-wall system) LH (Hybrid LLRS)
RiskScape (GNS 2010) Constr. type category Reinforced concrete shear wall or tilt up panel Reinforced concrete moment resisting frame (to include hybrid wall/frame)
Steel braced frame or steel moment resisting frame
Light timber
LO (Other LLRS)
-
LWAL (Wall)
Brick masonry (to include stone masonry)
LWAL (Wall) LWAL (Wall)
Concrete masonry
-
Unknown commercial
Total 19,885 Notes: * = building groups where estimated % of total adjusted for date of construction bias **= it is anticipated that many dual RC wall/frame systems have likely been documented as simply RC frames RCF = reinforced concrete frame; URBM = unreinforced brick masonry; URM = unreinforced masonry, which includes both brick and stone construction; URSM = unreinforced stone masonry
240
Appendix A. Additional information pertaining to commercial building typological categories in Auckland, New Zealand
Table A.2. Summary of documented building storeys above grade Storeys above grade category
Documented # bldgs
% excl. unknown
Storeys above grade 1 2 3 4 5 6 7
Documented # bldgs with # storeys 2972 2991 670 269 155 89 47
% of total excl. unknown 40% 40% 9% 4% 2% 1% 1%
1–3
6633
89%
4–7
560
7%
8+
295
4%
8+
295
4%
Unknown
12397
-
-
-
Total
19,885
100%
-
7488
100%
Table A.3. Summary of documented building construction year ranges Year of construction/reconstruction/retrofit category
Documented # bldgs
% of total excl. unknown
Pre-1935 1935–1965 1966–1976 1977–1992 1993+ Unknown
2940 5096 3718 4574 3264 293
15% 26% 19% 23% 17% -
Total
19,885
100%
241
Appendix A. Additional information pertaining to commercial building typological categories in Auckland, New Zealand Table A.4. Summary of building occupancy / usage type attributes Auckland Council notation Use category
Documented # bldgs
% of total incl. unknown
Avg. imp. level (NZS 2002)
Hostel
31
0.2%
2.0
Hotel
42
0.2%
2.4
Motel
7
0.0%
2.0
Office/residential
0
0.0%
0.0
Retail/residential
0
0.0%
0.0
Church
328
1.6%
2.3
Cinema Theatre Gambling
9 11 0
0.0% 0.1% 0.0%
2.8 2.4 0.0
Commercial
9853
49.5%
2.0
Funeral parlour
3
0.0%
2.0
Office
1137
5.7%
2.0
Office/retail
0
0.0%
0.0
Offices
3
0.0%
2.0
Restaurant
244
1.2%
2.1
Retail
1887
9.5%
2.0
Retail/café
0
0.0%
0.0
Retail/office
0
0.0%
0.0
Bank
93
0.5%
2.1
Café
129
0.6%
2.0
Hazchem store
1
0.0%
2.0
Shopping centre
30
0.2%
2.5
Supermarket
43
0.2%
2.2
Club
42
0.2%
2.0
Community facility
280
1.4%
2.3
Events centre
12
0.1%
2.8
Hall
21
0.1%
2.1
Library
34
0.2%
2.4
Education
1109
5.6%
2.2
GEM (2013) Occupancy category level 1
Occupancy category level 2
RES (Residential)
RES3 (Temporary lodging)
Riskscape (GNS 2010) Use category
Commercial - Accommodation MIX (Mixed use)
MIX2 (Mostly commercial and residential) ASS1 (Religious gathering)
ASS (Assembly)
Religious
ASS3 (Cinema or concert hall) COM5 (Entertainment)
COM3 (Offices, professional/tehcnical services) Commercial - Business
COM (Commercial and public)
COM1 (Retail trade)
Fast Moving Consumer Goods
EDU (Education)
242
COM6 (Public building)
Community
EDU99 (Education, unknown
Education
Appendix A. Additional information pertaining to commercial building typological categories in Auckland, New Zealand Table A.4. Summary of building occupancy / usage type attributes Auckland Council notation
GEM (2013)
Riskscape (GNS 2010)
Use category
Documented # bldgs
% of total incl. unknown
Avg. imp. level (NZS 2002)
Institutional
0
0.0%
0.0
type)
Preschool
595
3.0%
2.0
EDU1 (Pre-school facility)
Emergency services facility
192
1.0%
3.7
GOV2 (Government, emergency response)
Fire Station or Police
11
0.1%
3.0
15
0.1%
3.2
GOV1 (Government, general services)
Government
COM4 (Hospital/medical clinic)
Hospital, Clinic
Courts and judicial services Government Prison
19
0.1%
3.1
Hospital
205
1.0%
3.0
Medical centre
329
1.7%
2.6
Laboratory
1
0.0%
3.0
Garage / shed
6
0.0%
2.2
Warehouse
288
1.4%
2.1
Warehouse (retail)
41
0.2%
2.0
Factory
98
0.5%
2.0
Workshop
366
1.8%
2.0
Funpark
2
0.0%
3.0
Gallery
17
0.1%
2.1
Museum
14
0.1%
2.2
Recreation
0
0.0%
0.0
Recreation centre
31
0.2%
2.7
Tavern
90
0.5%
2.0
Petrol holding tanks
4
0.0%
4.0
Petrol station
80
0.4%
2.0
Post office
3
0.0%
2.0
Telecommunications
3
0.0%
3.0
Toilet block
13
0.1%
1.8
Occupancy category level 1
GOV (Government)
Occupancy category level 2
Use category
COM (Commercial and public) COM2 (Wholesale trade and storage (warehouse))
IND (Industrial)
IND99 (Industrial, unknown type)
Industrial - Manufacturing, Storage
IND2 (Light industrial)
COM (Commercial and public)
COM11 (Recreation and leisure)
Lifestyle
OCO (Other occupancy type)
OCO (Other occupancy type)
Lifeline Utilities
243
Appendix A. Additional information pertaining to commercial building typological categories in Auckland, New Zealand Table A.4. Summary of building occupancy / usage type attributes Auckland Council notation Documented # bldgs
% of total incl. unknown
Avg. imp. level (NZS 2002)
Tower
1
0.0%
5.0
Utility station
293
1.5%
3.7
Demolished
2
0.0%
2.0
Derelict
42
0.2%
2.0
Vacant site
184
0.9%
2.0
Dam
10
0.1%
5.0
Use category
Graveyard
1
0.0%
1.0
Greenhouse
2
0.0%
2.0
Heritage
20
0.1%
2.1
Unknown
89
0.4%
2.0
Car yard
79
0.4%
1.6
Office/car yard
0
0.0%
0.0
Carparking building
29
0.1%
2.0
GEM (2013) Occupancy category level 1
Riskscape (GNS 2010)
Occupancy category level 2
Use category
Clear Site
Other
OC99 (Unknown occupancy type)
OC99 (Unknown occupancy type)
COM (Commercial and public)
COM7 (Covered parking garage)
RES (Residential)
RES2 (Multi-unit, unknown type)
Parking
Resthome
41
0.2%
2.0
Heritage residential
0
0.0%
0.0
Resthome
Residential
850
4.3%
2.0
Residential (Large)
200
1.0%
2.0
Airfield
13
0.1%
3.1
Airport
148
0.7%
2.3
Mass transit station
8
0.0%
3.3
Military facility
101
0.5%
2.1
GOV (Government)
GOV99 (Government, unknown type)
Total
19,885
100%
-
-
-
Residential Dwellings RES2F (50+ Units) COM10 (Airport)
COM (Commercial and public)
244
COM8 (Bus station) or COM9 (Railway station)
Territorial Authority/Civil Defence
-
Appendix B. Register of surveyed RC moment resisting frame buildings in Auckland, New Zealand
Appendix B. Register of surveyed RC moment resisting frame buildings in Auckland, New Zealand The New Zealand Department of Building and Housing [now part of the Ministry of Business, Innovation and Employment (MBIE)] commissioned consultants to compile a register of reinforced concrete (RC) frame buildings throughout the country with three storeys or more that were granted building permits or consents between 1982 and 1995. A total of 168 buildings in Auckland were identified as meeting the selection criteria, although some eligible buildings were likely overlooked in the process. The table in this appendix lists the register of 168 buildings provided to the Auckland Council by MBIE, as discussed in Chapter 2. The register has been re-formatted, but otherwise is unchanged. No further validation of the data in the register has been made by the author since its receipt from the Auckland Council. The following notation is used in the table in this appendix: MF W BW TT HC RI PCS IS MD ?
RC moment resisting frame RC wall Reinforced masonry block wall Double tees Hollowcore Rib and infill Precast slab (other) In situ Metal deck Unknown
Please note that the buildings included in this register were simply considered for further investigation by MBIE and the researchers from the University of Auckland and are not necessarily ―earthquake-prone‖ per national legislation.
245
Appendix B. Register of surveyed RC moment resisting frame buildings in Auckland, New Zealand
Total # storeys above grade
Street address
3
12 Boston Road
3 3
125 Vincent St 14 Silver Road
3
83 Union St
3 3 3 3 3
17 Falcon St 18 Falcon St 19 Falcon St 22 Pollen Street 41-45 Sale Street
3
65 New North Road
3 3
105 Hurstmere Road 179 Onehunga Mall
3
439 Dominion Rd
3 3
473-529 Karangahape Rd 70 Stanley St 1 Clyde Road
3
171 Ponsonby Rd
3 3 3 3 3 3 3
231 Orakei Rd 12 Anzac Street 30 Ponsonby Rd 39 Anzac Road 42 Anzac Road 492-494 Queen St 9 Anzac Street
3
Territorial authority (suburb)
Drawing dates
Engineer
Date constructed
Structural system
Floor system
pre-1987
Project Construction
circa 1987
BW
?
1984 ?
Ian L Watson ?
1984-1985 circa 1996
BW BW
? ?
1984
Project Construction
Circa 1984
BW
RI
1987 1987 1987 pre-1986 1984
Brown & Thompson Brown & Thompson Brown & Thompson Smith and Henry Project Construction Ltd
Circa 1987 Circa 1987 Circa 1987 circa 1986 Circa 1984
BW&MF BW&MF BW&MF BW&MF BW&MF
PCS PCS PCS ? ?
?
Smith Leuchars
circa 1985
BW&MF
?
1984 1989
McGuigan Syme Partners Ltd Thorburn Davidson
1984 Circa 1989
BW&MF BW&MF
HC HC
1994
Buller George Engineers
Circa 1995
BW&MF
HC
Auckland (Newton)
1987
Holmes Consulting Group
Circa 1989
BW&MF
HC
Auckland (Parnell) Auckland (North) Auckland (Freemans Bay) Auckland (Remuera) Auckland (North) Auckland (Ponsonby) Auckland (North) Auckland (North) Auckland (Central) Auckland (North)
1987 1987
Project McGuigan Syme Partners Ltd
Circa 1987 1987
BW&MF BW&MF
HC MD
1993
Holmes Consulting Group
Circa 1994
BW&MF
RI
1987 ? 1984 ? ? 1986 1986
EDC ? Wass Buller & Associates ? ? Arup (Ove Arup & Partners) Fletcher Development
Circa 1987 ? Circa 1984 ? ? Circa 1986 1986
BW&MF BW&MF BW&MF BW&MF BW&MF BW&MF BW&MF
RI RI RI RI RI RI RI
Auckland (Mount Eden) Auckland (Central) Auckland (Epsom) Auckland (Freemans Bay) Auckland (Parnell) Auckland (Parnell) Auckland (Parnell) Auckland (Grey Lynn) Auckland (Central) Auckland (Eden Terrace) Auckland (North) Auckland (Onehunga) Auckland (Mount Eden)
246
Appendix B. Register of surveyed RC moment resisting frame buildings in Auckland, New Zealand
Total # storeys above grade 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3 3
Street address
Territorial authority (suburb)
Auckland (Mount Eden) Auckland (Three 981 Mount Eden Road Kings) 1 Jervoise Rd Auckland (Herne Bay) Auckland (Mount 2-4 Harrison Rd Wellington) 60-66 France Street Auckland (Newton) South 78-96 New North Auckland (Eden Road Terrace) Auckland (Mount 945A New North Road Albert) 13 Blake St Auckland (Ponsonby) Auckland (Eden 155 New North Road Terrace) 159 Queens Road Auckland (Panmure) 17 Anzac Street Auckland (North) 20 Anzac Street Auckland (North) 23 Anzac Street Auckland (North) Auckland (Mount 264 Mount Eden Road Eden) 29 Union St Auckland (Central) Auckland 80 Broadway (Newmarket) 88 Anzac Ave Auckland (Central) 6 Osterley Way, Auckland (South) Manakau 30 York Street Auckland (Parnell) Auckland (Mount 28 Mount Eden Rd Eden) 50 Birkenhead Avenue Auckland (North) 26 Mount Eden Rd
Drawing dates
Engineer
Date constructed
Structural system
Floor system
1995
JNG & Associates Ltd
?
BW&MF
TT
1985
Thorburn Davidson
Circa 1985
BW&MF
TT
1985
Wass Buller & Associates Ltd
Circa 1985
BW&MF
TT
1983
Geoffrey Dainty
Circa 1983
BW&MF
TT
1984
TMAC Consultants Ltd
Circa 1985
BW&MF
TT
1986
Holmes Wood Poole & Johnston
circa 1986
BW&MF
TT
1985
Wass Buller & Associates
Circa 1985
BW&MF
TT
1987
Project Construction Ltd
Circa 1987
BW&MF
TT&PCS
?
Smith Leuchars
circa 1987
MF
?
? 1987 ? ?
McGuigan Syme Canam Construction ? ?
Circa 1986 1987 ? ?
MF MF MF MF
? HC HC HC
?
J.M. Stiffe Hooker & Associates
Circa 1986
MF
HC
1985
Williamson Partnership
Circa 1985
MF
HC
1992
Various
circa 1994
MF
HC
1994
Carl R. O'Grady
Circa 1994
W
HC
1984
McGuigan Syme Partners Ltd
1985
W&MF
RI
?
Royds Garden
circa 1994
W&MF
?
1994
Thorburn Consultants Ltd
Circa 1995
W&MF
HC
1994
TSE Group Ltd
Circa 1994
W&MF
HC
247
Appendix B. Register of surveyed RC moment resisting frame buildings in Auckland, New Zealand
Total # storeys above grade 3 3 3 3 3 3 3 3 4 4 4
Street address
Territorial authority (suburb)
111 Great South Road Auckland (Greenlane) 111-115 Grafton Road Auckland (Grafton) 128-138 Parnell Road Auckland (Parnell) 22 Amersham Way, Auckland (South) Manakau Auckland (Eden 3 Diamond Street Terrace) Auckland (Freemans 100 College Hill Bay) 202 Ponsonby Rd Auckland (Ponsonby) Auckland 2 Gillies Ave (Newmarket) 3-5 Cheshire St Auckland (Parnell) 137 Great North Road Auckland (Grey Lynn) 20 Falcon St Auckland (Parnell)
Drawing dates
Engineer
Date constructed
Structural system
Floor system
1984 1982 ?
Fletcher ? McGuigan Syme
circa 1984 circa 1983 ?
W&MF W&MF W&MF
HC HC HC
pre-1987
?
1987
W&MF
HC
1986
Project Construction Ltd
Circa 1988
W&MF
IS
1993
Royds
circa 1993
W&MF
TT
1987
Wass Buller & Associates Ltd
Circa 1987
W&MF
TT
?
Heathcote Hold.- RAMP only
Circa 1995
W&MF
HC
1994 ? 1987
Circa 1984 circa 1986 Circa 1987
BW BW&MF BW&MF
TT IS PCS
Circa 1986
BW&MF
RI
Circa 1986 Circa 1994 Circa 1984-85 Circa 1987
BW&MF BW&MF BW&MF BW&MF
?? HC HC HC
4
81 Grafton Rd
Auckland (Grafton)
1986
4 4 4 4
60 Federal St 2-4 Upper Queen St 1-3 Ruskin St 60 Stanley St
1986 1994 1984 1987
4
81 New North Rd
1983
Holmes Wood Poole & Johnstone Ltd
Circa 1983
BW&MF
HC
4 4
9 madeira lane 99 Grafton Rd
1985 ?
Wass Buller & Associates Ltd Stuart McCondach
Circa 1985 Circa 1986
BW&MF BW&MF
HC HC
4
5 Porters Avenue
?
Wass Buller
Circa 1986
BW&MF
IS
4
15 Day St
1985
TMAC Consultants Ltd
circa 1985
BW&MF
MD
4
3 Broadway
Auckland (Central) Auckland (Central) Auckland (Parnell) Auckland (Parnell) Auckland (Eden Terrace) Auckland (Grafton) Auckland (Grafton) Auckland (Eden Terrace) Auckland (Central) Auckland (Newmarket)
McGuigan Syne Partners Ltd Smith Leuchars Brown & Thompson Lewis & Williamson Consulting Engineers Holmes Wood Poole & Johnstone Ltd John Chapple R N Henry Project
1983
Baker Developments Ltd
Circa 1983
BW&MF
PCS&TT
248
Appendix B. Register of surveyed RC moment resisting frame buildings in Auckland, New Zealand
Total # storeys above grade
Street address
4
1 Broadway
4 4 4 4 4
161-169 Hobson St 354-378 Manukau Rd 5 Howe Street 73 Anzac Avenue 79 Grafton Road 22-28 Beresford Square 73 Anzac Ave 130-138 St. Georges Bay Road
4 4 4 4
131 New North Road
4
51 Hurstmere Road
4
114 Dominion Road
4 4 5 5 5 5 5 5 5 5 5 5
29 Northcroft Street 490 Richmond Rd 21 Falcon St 500 Queen St 86 Federal St 205 Wairau Road 239 Queen St 200 Victoria St 89 Grafton Rd 65-71 Federal St 5 Whitaker Place 60 Cook St
Territorial authority (suburb)
Drawing dates
Engineer
Date constructed
Structural system
Floor system
1983?
Baker Developments
circa 1983??
BW&MF
TT
1984 1986 1986 1988 1984
Smith Leuchars Ltd Thorburn Davidson Wass Buller & Associates Holmes Consulting Group Lewis & Williamson
Circa 1984 Circa 1987 Circa 1986 Circa 1988 circa 1984
BW&MF MF MF MF W
TT HC HC TT TT
Auckland (Central)
1994
Law Sue Consultants Ltd
Circa 1994
W&MF
IS
Auckland (Central)
1988
Holmes Consulting Group
Circa 1988
W&MF
TT
Auckland (Parnell)
?
Smith and Henry
Circa 1986
W&MF
?
?
Brown and Thomson
circa 1990
W&MF
?
1984
Holmes Wood Poole & Johnstone
Circa 1985
W&MF
HC
pre-1987
Stiffe Hooker
circa 1987
W&MF
RI
1985 1986 1987 1984 1986 1987 1984 1985 1984 1983 1984 1985
Smith & Henry Peter Radley & Associates Brown & Thompson Holmes Wood Poole & Johnstone Ltd Smith Leuchars Ltd Stuart McCondach Holmes Wood Poole & Johnstone Ltd James P Verstoep Stuart McCondach J.M.Stiffe Hooker & Associates Carl R. O'Grady Holmes Wood Poole & Johnstone Ltd
Circa 1985 Circa 1997 Circa 1987 Circa 1985 Circa 1986 1987 Circa 1984 Circa 1985 Circa 1984 Circa 1983 Circa 1984 Circa 1986
W&MF W&MF BW& MF BW&MF BW&MF BW&MF BW&MF BW&MF BW&MF BW&W&MF MF MF
TT TT PCS HC HC HC HC RI TT HC ? PCS
Auckland (Newmarket) Auckland (Central) Auckland (Epsom) Auckland (Central) Auckland (Central) Auckland (Grafton)
Auckland (Eden Terrace) Auckland (North) Auckland (Mount Eden) Auckland (North) Auckland (Grey Lynn) Auckland (Parnell) Auckland (Central) Auckland (Central) Auckland (North) Auckland (Central) Auckland (Central) Auckland (Grafton) Auckland (Central) Auckland (Grafton) Auckland (Central)
249
Appendix B. Register of surveyed RC moment resisting frame buildings in Auckland, New Zealand
Total # storeys above grade
Street address
Territorial authority (suburb)
Drawing dates
Engineer
Date constructed
Structural system
Floor system
Auckland (South)
1985
Stuart McCondach
1985
W&MF
HC
5
21 Putney Way, Manakau 347 Parnell Rd
Auckland (Parnell)
1990
Circa 1990
W&MF
HC
5
449 karangahape Rd
Auckland (Central)
1987
Circa 1986
W&MF
HC
5
Auckland (Central)
1983
Circa 1984
W&MF
HC
Auckland (North)
1986
Holmes, Wood Poole & Johnstone
1986
W&MF
PCS
5 5 5 5 6 6
65-71 Federal Street 129-155 Hurstmere Road 171 Hobson St 22 Centre Street 308-318 Parnell Rd 8-12 Albert St 100 Carlton Gore 34 Sale Street
Wass Buller & Associates Tmac Consulting Civil & Structural Engineers J.M Stiffe Hooker & Associates
1984 1987 ? 1995 1987 1987
Smith Leuchars Ltd Brown & Thompson TSE Group Consultants Ltd Murray Jacobs Ltd Holmes Wood Poole & Johnstone TMRS?? Hard to read
Circa 1984 Circa 1987 Circa 1984 Circa 1995 Circa 1987 Circa 1987
W&MF W&MF W&MF W&MF BW&MF BW&MF
TT TT TT TT HC HC
6
235-237 Broadway
1986
Bruce Wallace Parners Ltd
Circa 1986
BW&MF
HC
6 6
106 Vincent St 16 Liverpool St
1983 1982
Booth Sweetman and Wolfe J.M. Stiffe Hooker & Associates
Circa 1983 Circa 1993
MF MF
HC HC
6
2/135-151 Broadway
1987
Wass Buller & Associates
Circa 1987
W&MF
HC
6 6
1987 1983
Murray Jacob Ltb Babbage Partners Ltd
Circa 1987 Circa 1983
W&MF W&MF
TT HC
Auckland (Central)
1987
Holmes Wood Poole & Johnstoe Ltd
Circa 1987
BW&MF
HC
7
30 Fort St 210 Federal St 100 Victoria Street West 16 Waverly St
Auckland (Central) Auckland (Central) Auckland (Parnell) Auckland (Central) Auckland (Central) Auckland (Central) Auckland (Newmarket) Auckland (Central) Auckland (Central) Auckland (Newmarket) Auckland (Central) Auckland (Central)
1985
J.M. Stiffe Hooker & Associates
Circa 1985
BW&MF
RI
7
187-193 Broadway
1987
Arup (Ove Arup & Partners)
Circa 1987
W&MF
HC
7
520 Queen St
1983
W&MF
HC
23-25 Broadway
Circa 87
W&MF
TT
7
46-48 Nelson St
Carl R. O'Grady SH -David L Smith & Robert W. Henry Fletcher
Circa 1983
7
Auckland (Central) Auckland (Newmarket) Auckland (Central) Auckland (Newmarket) Auckland (Central)
Circa 1988
W&MF
TT
5
5
7
1987 1988
250
Appendix B. Register of surveyed RC moment resisting frame buildings in Auckland, New Zealand
Total # storeys above grade
Street address
Territorial authority (suburb)
Drawing dates
Engineer
8 8
75 Karangahape Rd 21 Day St
Auckland (Central) Auckland (Central)
mid-1986 1993
Beca Carter Hollings & Ferner Ltd Dainty Alderton & Associates
8
101-107 Queen Street
Auckland (Central)
1985
Hoadley Budge & Partners
Auckland (South)
1987
Auckland (Central) Auckland (Central) Auckland (Central)
8
15 Osterley Way, Manakau 9 City Road 18 Liverpool St 401 Queen Street 17 Putney Way, Manakau 219 Federal St
8
277-305 Bradway
8 8 8 8 8
9 9 9 9 9 10 10 10 11 11 11 12 13 13
20 Amersham Way, Manakau 53 Fort St 98-100 Symonds St 350 Queen Street 482-486 Great South Rd 44 Anzac Ave 21 Pitt Street 124 Vincent St 60 Airdale St 21 Pitt St 385 Queen St 3 Scotia Place 369 Queen St 68-70 Shortland Street
Date constructed
Structural system
Floor system
Circa 1986 Circa 1993 Extension Circa 1985
BW&MF BW&MF
HC&RI PC
BW&MF
PCS
Holmes Wood Poole & Johnstone Ltd
1987
MF
HC
1984 1985 ?
Wass Buller & Associates Beca Carter Hollings & Ferner Ltd Carl O'Grady
Circa 1984 Circa 1985 circa 1986
MF W W
HC MD TT
Auckland (South)
1986
Stuart McCondach
1986
W&MF
PCS
Auckland (Central) Auckland (Newmarket)
1987
McGuigian Syme Partners Ltd
Circa 1987
W&MF
RI
?
Wass Buller & Associates
Circa 1987
W&MF
TT
Auckland (South)
1986
Holmes Wood Poole & Johnstone Ltd
1986
W&MF
HC
Auckland (Central) Auckland (Grafton) Auckland (Central)
1986 ? ?
C.M. Strachan & Associates Carl R. O'Grady Murray Jacobs
Circa 1986 Circa 1982 circa 1982
W&MF W&MF W&MF
HC HC TT
Auckland (Otahuhu)
1986
McGuigan Syne Partners Ltd
Circa 1986
W&MF
TT
Auckland (Central) Auckland (Central) Auckland (Central) Auckland (Central) Auckland (Central) Auckland (Central) Auckland (Central) Auckland (Central) Auckland (Central)
1987 1988 1985 1987 1988 1985 1987 1988 1984
Smith Leuchars Ltd Smith Leuchars Ltd Smith Leuchars Ltd Holmes Wood Poole & Johnstone Ltd Smith Leuchars Ltd Beca Carter Hollings & Ferner Ltd Beca Carter Hollings & Ferner Ltd Holmes Consulting Group C.M. Strachan & Associates
Circa 1987 Circa 1988 Circa 1985 Circa 1987 Circa 1988 Circa 1986 Circa 1986 Circa 1988 Circa 1984
BW&MF MF W&MF MF W&MF W&MF W&MF BW&MF MF
HC HC TT MD HC TT PCS TT HC
251
Appendix B. Register of surveyed RC moment resisting frame buildings in Auckland, New Zealand
Total # storeys above grade
Street address
Territorial authority (suburb)
Drawing dates
13
15 Hopetoun St
Auckland (Central)
1986
13
205-215 Hobson Street
Auckland (Central)
1994
13 14 14 14 14 14 14 15 15
87-89 Albert St 63 Albert St 50-52 Eden Cresent 16 Mount St 238 Queen St 97 Shortland St 57 Fort Street 290 Queen St 4-8 Short St 12-26 Swanson St/3844albert st 20 Waterloo Quadrant 396-404 Queen Street 36 Kitchener Street 117 Victoria Street West 23 Customs St East 9 Princes St 52 Sawanson St 5-7 Byron Avenue 152 Quay St 6 whitaker Place 45 Queen St 51-53 Shortland St 89-95 Victoria Street West
Auckland (Central) Auckland (Central) Auckland (Central) Auckland (Central) Auckland (Central) Auckland (Central) Auckland (Central) Auckland (Central) Auckland (Central)
15 15 15 15 16 16 16 16 17 17 17 18 18 19
Engineer
Date constructed
Structural system
Floor system
Circa 1986
MF
RI
Circa 1994
W&MF
HC
1984 1986 1995 pre-1989 1983 1994 1985 1983 1993
Babbage Partners Ltd Arup (Ove Arup & Partners)/Soon Loo Consulting Engineer Worley Consultants Limited Fletcher Day Consultants Beca Holmes Wood Poole & Johnstone Ltd Buller George Engineers Holmes Wood Poole & Johnson Ltd Fletcher Arup (Ove Arup & Partners)
Circa 1984-85 Circa 1986 Circa 1996 circa 1989 Circa 1983 Circa 1995 Circa 1986 Circa 1983 Circa 1993
W&MF BW&MF MF W&MF W&MF W&MF W&MF BW&MF BW&MF
TT HC HC HC HC HC TT HC RI
Auckland (Central)
pre-1985
Smith Leuchars Ltd
Circa 1985
MF
TT
Auckland (Central) Auckland (Central) Auckland (Central)
1987 ? 1987
Murray Jacobs Consulting Engineers Holmes Wood Poole and Johnstone Wass Buller & Associates
Circa 1987 circa 1989 Circa 1987
MF W&MF W&MF
TT HC PCS
Auckland (Central)
1994
Buller George Engineers
Circa 1995
MF
HC
Auckland (Central) Auckland (Central) Auckland (Central) Auckland (North) Auckland (Central) Auckland (Grafton) Auckland (Central) Auckland (Central)
1987 1988 ? 1987 1984 1994 1982 1984
Smith Leuchars Ltd Smith Leuchars Ltd Holmes Wood Poole & Johnstone Ltd Homes Wood Poole & Johnstone Wass Buller & Associates Ltd Buller George Engineers Beca Carter Hollings & Ferner Ltd Smith Leuchars Ltd
Circa 1987 Circa 1988-89 Circa 1987 1987 Circa 1984 Circa 1995 Circa 1982 Circa 1984
MF W&MF W&MF BW&MF W&MF W&MF W&MF W&MF
HC HC PCS HC HC HC IS&TT TT
Auckland (Central)
1994
Connell Wagner
Circa 1994
MF
HC
252
Appendix B. Register of surveyed RC moment resisting frame buildings in Auckland, New Zealand
Total # storeys above grade
Street address
Territorial authority (suburb)
Drawing dates
Engineer
Date constructed
Structural system
Floor system
19 19 28 35 41
48 Emily Place 205-225 Queen St 125 Queen St 135 Albert St 23-29 Albert St
Auckland (Central) Auckland (Central) Auckland (Central) Auckland (Central) Auckland (Central)
1987 1987 1983 1988 1989
Holmes Wood Poole & Johnstone Ltd Bricknell Moss Rains & Stevens Ltd Murray Jacobs Consulting Engineers Murray Jacobs Ltd Holmes Consulting Group
Circa 1987 Circa 1987 Circa 1983 Circa 1988 Circa 1989
W&MF W&MF BW&MF W&MF W&MF
HC MD TT MD TT
253
Appendix B. Register of surveyed RC moment resisting frame buildings in Auckland, New Zealand
254
Appendix C. Register of surveyed URM buildings in Auckland, New Zealand
Appendix C. Register of surveyed URM buildings in Auckland, New Zealand Auckland Council Civil Defence and Emergency Management (CDEM) commissioned researchers from the University of Auckland to assist CDEM in documenting and assessing a selection of unreinforced brick masonry (URBM) buildings in the Auckland region most likely to be vulnerable to earthquakes. On that basis, a survey of the geometric characteristics of 206 URBM buildings located in Auckland was conducted in order to get a representative distribution of the geometric attributes that are inputs into the out-of-plane assessment procedure discussed in Chapter 3. The table in this appendix lists the register of the 206 URBM buildings which were surveyed and includes the dimensions of the walls assumed to be most vulnerable to out-of-plane collapse on each building. The buildings typologies listed in the table in this appendix are defined in Section 3.3.1. Please note that the buildings included in this register were simply considered for further investigation by CDEM and the researchers from the University of Auckland and are not necessarily ―earthquake-prone‖ per national legislation.
255
Appendix C. Register of surveyed URM buildings in Auckland, New Zealand
Building identification and typology
Wall thickness, cavity unrestrained (mm)
Wall heights (mm)
Building name
Street address
Building typology
Total # storeys above grade
HG
Albert-Eden local board Two fifteen brothers Burgerfuel
135 Dominion Road 215 Dominion Road 216-220 Dominion Road
A E E
1 3 3
3100 2600 2900
ANZ Bridgeman erected buildings $2 and $3 and more Antique Alley Xi An Noodle Touch Beauty
227-231 Dominion Road 234 Dominion Road 239 Dominion Road 240 Dominion Road 242 Dominion Road 245 Dominion Road
C D D D D D
2 2 2 2 2 2
Fresh World Geoffs emporium Clare Inn Boonchu Thai food Brazzers books
262-270 Dominion Road 273 Dominion Road 274 Dominion Road 276-278 Dominion Road 313 Dominion Road 314 Dominion Road
B D D D D B
Bouncha Thai restaurant Tasca Laurel kitchen Liqourland Burnley Suprette Merediths
331 Dominion Road 336-338 Dominion Road 340 Dominion Road 346 Dominion Road 355-361 Dominion Road 367-369 Dominion Road
Groom Mt Eden Methodist Church Anglican Church Shanton Malaysian restaurant
373-375 Dominion Road 426 Dominion Road 443 Dominion Road 449-453 Dominion Road 453-458 Dominion Road
HPAR
tG
t1
t2
tPAR
0 0 2300 2700 2800 2800
1500 500 0
110 110 110
0 110 110
0 110 110
230 230 0
3800 3400 3200 3600 3000 3300
3200 3300 3200 3300 3200 3100
0 0 0 0 0 0
1500 1000 600 1700 1300 600
110 110 110 110 350 350
110 110 110 110 230 350
0 0 0 0 0 0
230 230 230 230 230 230
1 2 2 2 2 2
3100 3600 2700 3000 2900 3000
0 3300 2700 2800 2800 3100
0 0 0 0 0 0
1400 1300 1200 1800 1000 1000
350 350 350 110 350 110
0 230 230 110 350 110
0 0 0 0 0 0
230 230 230 230 230 230
D D B B B B
2 2 1 1 1 1
3000 3100 3700 3400 2900 3100
2800 3100 0 0 0 0
0 0 0 0 0 0
1700 1100 1700 2300 1700 1700
350 230 350 350 110 350
350 230 0 0 0 0
0 0 0 0 0 0
230 230 230 230 230 230
C C C D D
2 2 2 2 2
3200 4800 2700 3000 2900
3200 5000 4500 2800 3100
0 0 0 0 0
1300 0 800 1000 1700
350 110 350 350 350
350 110 230 230 230
0 0 0 0 0
230 0 230 230 230
256
H1
H2
Appendix C. Register of surveyed URM buildings in Auckland, New Zealand
Building identification and typology
Wall thickness, cavity unrestrained (mm)
Wall heights (mm)
Building name
Street address
Building typology
Total # storeys above grade
HG
H1
H2
HPAR
tG
t1
t2
tPAR
Yummy Family
463-467 Dominion Road 471-473 Dominion Road 533-553 Dominion Road
D C D
2 2 2
2900 2900 3200
2900 2800 3200
0 0 0
1100 1300 800
350 110 350
230 110 230
0 0 0
230 230 230
594-600 Dominion Road 602-614 Dominion Road 616 Dominion Road 618-636 Dominion Road 638 Dominion Road 727-731 Dominion Road
D E B D D C
2 3 2 2 2 2
2900 3200 3000 3200 3000 3100
2900 0 5400 2600 2000 0 3400 0 3000 0 3500 0
1400 1500 0 2500 1500 1100
350 110 110 110 350 350
230 110 110 110 230 350
0 110 0 0 0 0
230 230 0 230 230 230
758 Dominion Road 767-771 Dominion Road 883-887 Dominion Road 950-954 Dominion Road 958 Dominion Road 999 Dominion Road
D C D D B D
2 2 2 2 1 2
3000 3500 3400 3000 3500 2600
2400 3800 3300 3100 0 2600
0 0 0 0 0 0
0 1600 1400 1000 1800 1100
350 350 110 110 110 350
230 230 110 110 0 230
0 0 0 0 0 0
0 230 230 230 230 230
1001 Dominion Road 1079 Dominion Road 1238 Dominion Road 171 Great North Road 533 Great North Road 576-580 Great North Road
B A D D D D
1 1 2 2 2 2
4000 2700 3200 3800 3400 3100
0 0 3200 3600 2800 3100
0 0 0 0 0 0
1200 600 1000 1300 1500 1200
110 350 350 110 110 350
0 0 230 110 110 230
0 0 0 0 0 0
230 230 230 230 230 230
596 Great North Road 1216 Great North Road 1220 Great North Road 238-240 Great South Road 275-285 Great South Road
D D F D D
2 2 3 2 2
3900 3500 3500 4200 3000
3200 0 2800 0 2800 2800 3100 0 3000 0
1200 1800 1200 1100 1400
110 110 350 350 110
110 110 350 230 110
0 0 230 0 0
230 230 230 230 230
Daxas
Ngaire Chambers Rocklands buildings The room (cheapside) Amazes Hairmoney Landscape dairy Masport Yong e restaurant Suprette Zheng Kee restaurant Photo Warehouse Barfoot and Thompson
Chev mini store Turkish Kebabs Barber The Big Apple
257
Appendix C. Register of surveyed URM buildings in Auckland, New Zealand
Building identification and typology
Wall thickness, cavity unrestrained (mm)
Wall heights (mm)
Building name
Street address
Building typology
Total # storeys above grade
HG
H1
H2
HPAR
tG
t1
t2
tPAR
One Mark Boss Fashions Lowest price in NZ
276-282 Great South Road 286-288 Great South Road 293 Great South Road
D B D
2 1 2
3400 3300 3100
3100 0 3100
0 0 0
1100 1900 1500
110 110 110
110 0 110
0 0 0
230 230 230
NZ herb H & M café Roop Ki Rani Relon Shoe world Dollar Store 1, 2, and 3
296 Great South Road 303 Great South Road 310 Great South Road 327 Great South Road 333 Great South Road 349 Great South Road
D D D D D D
2 2 2 2 2 2
2800 3100 2800 2900 2900 2800
2700 3100 2800 2900 2900 2800
0 0 0 0 0 0
1200 1920 1800 1700 1500 1100
350 110 350 350 350 110
230 110 230 230 230 110
0 0 0 0 0 0
230 230 230 230 230 230
Big Bear Besmart Gazety Theatre Gentral Servilles Auckland Savings bank
357 Great South Road 385 Great South Road 452 Great South Road 475-481 Great South Road 2-6 Jervois Road 15-17 Jervois Road
D D D B D D
2 2 2 2 2 2
3500 2800 2900 3000 3400 3500
3200 2800 2700 2900 3900 3500
0 0 0 0 0 0
2100 0 1000 1300 1200 1000
110 350 350 350 350 350
110 230 350 230 350 350
0 0 0 0 0 0
230
JSH Upreality
72 Jervois Road 162-164 Jervois Road 172 Jervois Road 184-190 Jervois Road 192-196 Jervois Road 198-202 Jervois Road
C D D D D D
2 2 2 2 2 2
3200 3400 3800 3300 4100 3300
3000 3400 3700 3300 4000 3100
0 0 0 0 0 0
700 1400 0 500 1200 600
350 350 350 350 350 110
230 350 230 230 230 110
0 0 0 0 0 0
230 230
210-212 Jervois Room 214-218 Jervois Road 220 Jervois Road 224-232 Jervois Road 234-236 Jervois Road
D D A D B
2 2 1 2 1
3300 3200 3100 3800 3200
3400 3200 0 3700 0
0 0 0 0 0
1100 500 1200 1200 500
350 110 110 350 350
230 110 0 350 0
0 0 0 0 0
230 230 230 230 230
Exeter building Adimiao The elbow room Dellons kitchen Mckenneys building Fruit
258
230 230 230 230
230 230 230
Appendix C. Register of surveyed URM buildings in Auckland, New Zealand
Building identification and typology
Wall thickness, cavity unrestrained (mm)
Wall heights (mm)
Building name
Street address
Building typology
Total # storeys above grade
HG
H1
H2
HPAR
tG
t1
t2
tPAR
238-272 Jervois Road 7 Manakau Road 239 Manakau Road
D C D
2 2 2
3100 3200 3700
3200 3200 2700
0 0 0
900 0 1700
350 110 350
230 110 230
0 0 0
230
Toscana dairy Waymouths Pharmacy Mainly mirrors Zealandia house No1 BBQ seafood restaurant Active physio SBA Kidspace
260 Manakau Road 311 Manakau Road 345 Manakau Road 365 Manakau Road 371 Manakau Road 397 Manakau Road
D C B B B B
2 2 1 1 1 1
1560 3200 3400 2900 4600 2700
2600 3100 0 0 0 0
0 0 0 0 0 0
2400 0 1000 1500 1200 1600
350 230 350 230 110 350
230 230 0 0 0 0
0 0 0 0 0 0
230
Blinds Upholstery Sakerbar Nippon Golden Jade 3A copy and design Raven Alexandra dairy
409 Manakau Road 415 Manakau Road 417 Manakau Road 435 Manakau Road 437 Manakau Road 465-469 Manakau Road
D D D D A D
2 2 2 2 1 2
3600 3600 3600 3600 3600 3800
2900 2900 2900 2900 0 2800
0 0 0 0 0 0
2400 1000 1000 1000 1400 1700
350 350 350 350 350 350
230 230 230 230 0 230
0 0 0 0 0 0
230 230 230 230 350 230
Thai meal Antiques Simply wonderful clothes Hearting lofe Mr Barber Casa Del Gelato
481-485 Manakau Road 487-491 Manakau Road 569-573 Manakau Road 576-578 Manakau Road 604 Manakau Road 416-418 Mt Eden Road
B B B A B B
1 1 1 1 1 1
3200 3200 3500 2900 3000 2430
0 0 0 0 0 0
0 0 0 0 0 0
1600 1600 1800 1800 1300 2800
230 110 110 350 230 250
0 0 0 0 0 0
0 0 0 0 0 0
230 230 230 230 230 230
Pokeno Bacon Ltd Barfoot and Thompson Ltd The Candyman Mt Eden Bakery Mainly toys
422 Mt Eden Road 427 Mt Eden Road 428 Mt Eden Road 462 Mt Eden Road 539 Mt Eden Road
D C D D F
2 2 2 2 3
3000 3700 3200 3200 4000
0 500 700 1200 500
350 470 110 350 350
230 350 110 230 350
0 0 0 0 230
230 350 230 230 230
259
3000 0 4300 0 3700 0 3300 0 3600 3400
230
230 230 230 350
Appendix C. Register of surveyed URM buildings in Auckland, New Zealand
Building identification and typology
Wall thickness, cavity unrestrained (mm)
Wall heights (mm)
Building name
Street address
Building typology
Total # storeys above grade
HG
H1
H2
HPAR
tG
t1
t2
tPAR
Dominos The French Emporium Eden signs
547 Mt Eden Road 591 Mt Eden Road 611 Mt Eden Road
D B B
2 1 1
3600 3000 3000
3400 0 0
0 0 0
1600 1200 2000
110 350 350
110 0 0
0 0 0
350 350 350
Domett Real Estate Better butchers Exile hair
613 Mt Eden Road 693 Mt Eden Road 715 Mt Eden Road 741 Mt Eden Road 809 Mt Eden Road 41 New North Road
A F C C D D
1 3 2 2 2 2
3000 3000 2700 3100 3400 3100
0 0 3000 3000 2600 0 2900 0 2800 0 3000 0
2000 900 1100 0 1100 600
350 470 350 110 350 110
0 350 230 110 230 110
0 230 0 0 0 0
350 230 230 0 230 230
Grano SPCA Buildings Nexus Glengarry The pase coroner kingsland Portland buildings
46-48 New North Road 66-70 New North Road 345 New North Road 420 New North Road 460-466 New North Road 463-475 New North Road
D D C D F D
2 2 2 2 3 2
3500 4100 3900 2900 3400 3500
3500 0 2900 0 3300 0 2800 0 3300 3700 3300 0
1100 600 400 600 1100 1300
110 350 110 110 110 350
110 230 110 110 110 230
0 0 0 0 110 0
230 230 230 230 230 230
The kingslander Kingsland post office Chemist Mixt Nana bakery Laundromat
470 New North Road 478 New North Road 489-491 New North Road 502 New North Road 506 New North Road 777 New North Road
D C B A C D
2 2 1 1 2 2
3400 3500 3200 3000 2400 2900
3100 3500 0 0 3200 2400
1000 0 0 800 1700 2000
110 350 350 350 110 110
110 230 0 0 110 110
0 0 0 0 0 0
230 0 0 230 230 230
Asian food centre Peach garden
849 New North Road 895-901 New North Road 910-912 New North Road 932-934 New North Road 936-954 New North Road
F F B D D
3 3 1 2 2
2500 2500 3400 3100 3400
2800 3200 2800 2800 0 0 2700 0 3000 0
1000 1600 2000 0 1800
110 350 350 350 110
110 350 0 230 110
110 230 0 0 0
230 230 230 0 230
Dulcie May Kitchen
Mt Albert Noodle house At Hair design
260
0 0 0 0 0 0
Appendix C. Register of surveyed URM buildings in Auckland, New Zealand
Building identification and typology
Wall thickness, cavity unrestrained (mm)
Wall heights (mm)
Building name
Street address
Building typology
Total # storeys above grade
HG
H1
H2
HPAR
tG
t1
t2
tPAR
1924 ARAWA Cosset
962-974 New North Road 1007 New North Road 1095 New North Road
D A A
2 1 1
3400 2900 2900
3000 0 0
0 0 0
1200 1200 1000
110 350 110
110 0 0
0 0 0
230 230 230
Normanby vet clinic Columbus The crazy caféria North Memorials Cash trades Jellicoe
49 Normanby Road 120 Onehunga mall 127 Onehunga mall 129-131 Onehunga mall 134-136 onehunga mall 137 Onehunga mall
A C D D D D
1 2 2 2 2 2
3700 3900 3300 3400 3200 3000
0 3800 3600 3600 3500 4300
0 0 0 0 0 0
1300 1200 0 1300 1000 2000
110 350 350 350 110 110
0 350 230 350 110 110
0 0 0 0 0 0
230 230 0 230 230 230
Bake haven café Changes Onehunga community link Fruit land Brothers hair cuts Devon Dairy
172 Onehnunga mall 183 Onehunga mall 201-211 Onehnunga mall 208 Onehnunga mall 219-221 Onehnunga mall 223-225 Onehnunga mall
C D D D D D
2 2 2 2 2 2
3300 3900 3100 3600 3200 3900
4000 3400 2800 3300 3200 3800
0 0 0 0 0 0
2000 1000 1300 1600 2300 1300
350 110 350 350 110 110
350 110 230 350 110 110
0 0 0 0 0 0
230 230 230 230 230 230
Coin save Barfoot & Thompson State dairy
251-253 Onehunga mall 224-226 Onehunga mall 298 Onehunga mall 300 onehunga mall 372 Onehunga Mall 35-39 Park Road
C D B B A D
2 2 1 1 1 2
3000 3500 3000 3600 3200 3500
4000 3800 0 0 0 3500
0 0 0 0 0 0
2100 1500 2400 1200 1700 1300
110 110 110 110 110 110
110 110 0 0 0 110
0 0 0 0 0 0
230 230 230 230 230 230
Shahl Tank juices Live music Café lava
113-119 Parnell Road 125 Parnell Road 144 Parnell Road 373-379 Parnell Road 1 Patey Street
D D C D C
2 2 2 2 2
3400 3300 3800 3100 2800
2800 3700 3300 3000 2600
0 0 0 0 0
1100 1600 800 800 0
110 350 350 110 110
110 350 230 110 110
0 0 0 0 0
230 230 230 230 0
261
Appendix C. Register of surveyed URM buildings in Auckland, New Zealand
Building identification and typology
Wall thickness, cavity unrestrained (mm)
Wall heights (mm)
Building name
Street address
Building typology
Total # storeys above grade
HG
H1
H2
HPAR
tG
t1
t2
tPAR
Miss Ghabb
1 Ponsonby Road 2-6 Ponsonby Road 37-41 Ponsonby Road
C D D
2 2 2
3900 3400 3600
3500 4400 4500
0 0 0
1500 1600 500
110 350 110
110 230 110
0 0 0
230 230 230
71 Ponsonby Road 77 Ponsonby Road 78-82 Ponsonby Road 85 Ponsonby Road 118-126 Ponsonby Road 119-131 Ponsonby Road
B D D B D D
1 2 2 1 2 2
3000 3000 3300 3300 3100 4000
0 3200 4700 0 4000 4000
0 0 0 0 0 0
1400 1400 0 1500 1500 500
350 110 110 110 350 350
0 110 110 0 350 350
0 0 0 0 0 0
230 230 0 230 230 230
128 Ponsonby Road 132-134 Pinsonby Road 161 Ponsonby Road 166-168 Ponsonby Road 186-188 Ponsonby Road 199 Ponsonby Road
D D D D D C
2 2 2 2 2 2
3100 3900 3500 3500 3300 3600
4000 4500 3800 3700 5400 3500
0 0 0 0 0 0
1500 1200 600 400 800 0
350 350 350 110 110 350
350 350 230 110 110 230
0 0 0 0 0 0
230 230 230 230 230 0
209-215 Ponsonby Road 216-224 ponsonby Road 264-272 Ponsonby Road 275 Ponsonby Road 277-281 Ponsonby Road 285-291 Ponsonby Road
D D D B D D
2 2 2 1 2 2
4000 3000 3200 2900 3300 3300
3900 3900 2500 0 4800 3800
0 0 0 0 0 0
0 2400 400 1800 0 1000
350 110 110 350 350 110
230 110 110 0 230 110
0 0 0 0 0 0
0 230 230 230 0 230
286-292 Ponsonby Road 60 Princess Street 154-160 Remuera Road 279-281 - Remuera Road 339-345 Remuera Road
D A D D F
2 1 2 2 3
4000 4000 3200 3400 3300
3500 0 0 0 3100 0 3400 0 3200 3200
1000 1600 1400 1000 0
350 350 110 110 110
230 0 110 110 110
0 0 0 0 110
230 230 230 230 0
The garden party The fairy shop Minnie Cooper Suss & Bide
Kate Sylvester Troy Wallace Rose
Sliders Kilt Auckland ring company Ponsonby Buildings 1911 Pons Mahstrom La Barrique Pacific consultants
262
Appendix C. Register of surveyed URM buildings in Auckland, New Zealand
Building identification and typology
Wall thickness, cavity unrestrained (mm)
Wall heights (mm)
Building name
Street address
Building typology
Total # storeys above grade
HG
H1
H2
HPAR
tG
t1
t2
tPAR
Pheonix tree Keller Shoes
346 Remuera Road 352-354 Remuera Road 403 Remuera Road
A C D
1 2 2
3300 2900 3100
0 2900 2800
0 0 0
2000 1400 1900
110 110 110
0 110 110
0 0 0
230 230 230
405-415 Remuera Road 571-575 Remuera Road 579-585 Remuera Road 602-608 Remuera Road 612 Remuera Road 616-618 Remuera Road
D D D D B B
2 2 2 2 1 1
3100 3500 3500 3600 3300 3400
2800 3000 3000 3500 0 0
0 0 0 0 0 0
1900 1500 1500 800 1100 0
110 110 350 110 110 110
110 110 230 110 0 0
0 0 0 0 0 0
230 230 230 230 230 0
Urban flowers Papas pizzazz Willow shoes LJ Hooker Ascroft buildings
25-27 Sandringham Road 61-65 Sandringham Road 113 Sandringham Road 108 Sandringham Road 211-215 Sandringham Road 504 Sandringham Road
D C A A C A
2 2 1 1 2 1
3700 3600 3400 3800 3100 3300
3500 3400 0 0 3200 0
0 0 0 0 0 0
1200 1400 1300 2000 1800 1800
110 110 350 350 110 110
110 110 0 0 110 0
0 0 0 0 0 0
230 230 230 230 230 230
Wenell Sandringham Road Shubh Auckland halal meats Aradia Building Sandringham health centre
513 Sandringham Road 515-519 Sandringham road 520-524 Sandringham Road 526-530 Sandringham Road 521-531 Sandringham Road 542-546 Sandringham Road
C D B C D D
2 2 1 2 2 2
3600 3400 2100 3600 2900 3300
3300 4200 0 3400 2900 2900
0 0 0 0 0 0
1300 600 900 800 1300 800
110 350 110 110 110 350
110 350 0 110 110 350
0 0 0 0 0 0
230 230 110 230 230 230
Village kebab Bayleys Prague
533-541 Sandringham Road 571 Sandringham Road 599 Sandringham Road
B D C
1 2 2
3800 3300 3300
0 3200 3200
0 0 0
2000 700 700
110 110 350
0 110 350
0 0 0
230 230 230
Browns St jones Ray White Shahi
263
Appendix C. Register of surveyed URM buildings in Auckland, New Zealand
264
Appendix D. Register of Art Deco buildings in Napier, New Zealand
Appendix D. Register of Art Deco buildings in Napier, New Zealand The following table lists data amalgamated from a range of sources (McGregor 1998, 2003, 2012; City of Napier 2001, 2011; Shaw and Hallett 2002; Bilman et al. 2004; Stewart 2009; New Zealand Historic Places Trust 2012; see Chapter 4 references) as well as from physical observations by the researchers. Buildings still existing as of the end of 2012 are listed firstly in the order in which they appear in the most recent edition of the Art Deco Trust Inventory (Bilman et al. 2004; see Chapter 4 references). Buildings that have been demolished as of the end of 2012 are listed near the end of the appendix. While construction often took place over multiple calendar years, the initial construction year was recorded as a means of sorting and charting the data and because the first year of construction is more indicative of the design year, which is of greatest concern for purposes of seismic assessment. Please note that the buildings included in this register were simply considered for further investigation by the Art Deco Trust and the researchers from the University of Auckland and are not necessarily ―earthquake-prone‖ per national legislation.
265
24
Existing
Enclosed Building
1 Shakespeare Road
JA Louis Hay (Napier)
Not Recorded
Taylors Dry Cleaners
Existing
Enclosed Building
2 Hastings Street
H Faulknor
Abbotts Building
Existing
Enclosed Building
6-18 Hastings Street
JA Louis Hay (Napier)
District Plan Heritage Group
n/a
1932
Napier City District Plan Section
84
1923
NZ Historic Places Trust Classification
4
Lovegrove Bros.
Storeys (in approx height)
n/a
Finch & Westerholm (Napier)
Structure Type
n/a
11 Shakespeare Road
Spanish Mission
Not Recorded
2
n/a
City of Napier, Appendix 13
1
1934
Chicago School / Prairie
RC
2
1
H Faulknor
1935
Art Deco
RC
1
n/a
Not Recorded
1932
Art Deco
reinforced concrete
RC
2
n/a
1932
Spanish Mission
reinforced concrete
RC
2
n/a
City of Napier, Appendix 13
1
5
86
n/a
23
Former McKenzies Building
Existing
Enclosed Building
24 Hastings Street
Holuman, Moses & Watkins (Auckland)
6
113
4821
22, 36
Parkers Chambers
Existing
Enclosed Building
24A Hastings Street & 10 Herschell Street
JA Louis Hay (Napier)
WM Angus Ltd
1929
Existing
Enclosed Building
32 Hastings Street
Crichton McKay & Haughton (Wellington)
Fletcher Constructi on Co.
1933
Art Deco
1932
Art Deco
1932
Art Deco
1931
Art Deco
Construction Type Notes
83
Enclosed Building
Style
3
Existing
Shakespeare Hotel / Toad Hall (Former Empire Hotel) Wine Centre (Former AMP Building)
Approximate Date of Demolition
31
Approximate Date of Reconstruction
1107
Approximate Date of Original Construction
151
Builder (PostEQ Reconstr. if Applicable)
2
Architect (PostEQ Reconstr.if Applicable)
30
Street Address
Art Deco Trust Walking Tour Brochure #
n/a
Structure Type
NZ Historic Places Trust Registration #
152
2012 Status
Napier City District Plan Heritage Reference #
1
Name of Building
Art Deco Trust Inventory #
Appendix D. Register of Art Deco buildings in Napier, New Zealand
2
City of Napier, Appendix 13
1
Steel Frame and RC
2
2
City of Napier, Appendix 13
1
RC
2
2
reinforced concrete frame
RC
2
2
RC
2
n/a
RC
2
n/a
RC
2
n/a
1109
21
8
90
1137
20
Thorps Building
Existing
Enclosed Building
40 Hastings Street
JA Louis Hay (Napier)
8
90
1137
37
The Hay Building
Existing
Enclosed Building
4 Herschell Street
JA Louis Hay (Napier)
9
91
n/a
n/a
Cox's Building
Existing
Enclosed Building
46 Hastings Street
Natusch & Sons (Napier)
N Cole
1932
Art Deco
10
92
n/a
19
Hollands Building
Existing
Enclosed Building
48 Hastings Street
EA Williams (Napier)
Fletcher Constructi on Co.
1932
Spanish Mission
11
93
n/a
n/a
Former Robert Holt Building
Existing
Enclosed Building
52 Hastings Street
R Holt & Sons Ltd (Napier)
R Holt & Sons Ltd
1933
American Renaissance
Prouse & Wilson (Welington)
Edwards Constructi on Co.
1932
Art Deco
reinforced concrete
RC
2
2
Not Recorded
1932
Stripped Classical
reinforced concrete, retrofit steel braced framing
RC
2
1
Art Deco
RC
2
n/a
Art Deco
RC
2
n/a
96
1154
39
Masonic Hotel
Existing
Enclosed Building
13
97
1112
57
ASB Bank
Existing
Enclosed Building
100 Hastings Street
Crichton McKay & Haughton (Wellington)
14
98
n/a
n/a
Mutual Chambers
Existing
Enclosed Building
108 Hastings Street
Finch & Westerholm (Napier)
15
99
n/a
n/a
McClurgh's
Existing
Enclosed Building
116 Hastings Street
Natusch & Sons (Napier)
AB Davis & Sons Ltd Fletcher Constructi on Co.
266
1930
1932
1934
1
2
88
12
1
RC
7
64-74 Hastings Street & 2 Tennyson Street
1
reinforced concrete, brick façade front reinforced concrete floor with steel frame, other walls reinforced concrete with brick panels reinforced concrete & brick
Crombie Lockwood Building (Former Bank of New South Wales)
Fletcher Constructi on Co. Fletcher Constructi on Co.
City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13
reinforced concrete
City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13
1
1
1
1
1
1
1
1
1
103
n/a
66
Haynes Building
Existing
Enclosed Building
136 Hastings Street
JA Louis Hay (Napier)
Suburban Land and Constructi on Co.
1933
Art Deco
reinforced concrete and brick
RC
1
n/a
20
107
4835
63
Paxie's Building
Existing
Enclosed Building
180-184 Hastings Street
Finch & Westerholm (Napier)
Unknown
1932
Spanish Mission
reinforced concrete
RC
1
2
21
108
n/a
n/a
Former Northe's Building
Existing
Enclosed Building
192 Hastings Street
LG West, Son & Homibrook
Unknown
1932
Art Deco
RC
1
n/a
22
32
1158
60
NZ Post Building
Existing
Enclosed Building
1 Dickens Street
JT Mair (Wellington)
WM Angus Ltd
1930
Stripped Classical
Not Recorded
3
2
23
105
n/a
n/a
Hyde's Building
Existing
Enclosed Building
141-145 Hastings Street
Finch & Westerholm (Napier)
Holder Bros.
1932
Spanish Mission
RC
2
n/a
24
101
1132
59
Bennett's Building
Existing
Enclosed Building
131-139 Hastings Street
HA Westerholm (Napier)
WM Angus Ltd
1929
1931
Stripped Classical
RC
3
2
25
100
1133
58, 71
Blythe's Building
Existing
Enclosed Building
Natusch & Sons (Napier)
WM Angus Ltd
Pre1932
1933
Classical Revival
Not Recorded
2
2
26
42
1128
69
Criterion Hotel
Existing
Enclosed Building
EA Williams (Napier)
WM Angus Ltd
1932
18
The Market Reserve Building
Natusch & Sons (Napier)
Fletcher Constructi on Co.
27
157
4413
Existing
Enclosed Building
129 Hastings Street & 63 Emerson Street 8 Market Street & 48 Emerson Street 28-34 Tennyson Street & 65 Hastings Street 53-61 Hastings Street & 27-35 Tennyson Street
28
95
n/a
n/a
Bryant's Building
Existing
Enclosed Building
29
94
n/a
n/a
Ritchie's
Existing
Enclosed Building
41-45 Hastings Street
30
89
1143
25
Harston's
Existing
Enclosed Building
35 Hastings Street
Finch & Westerholm (Napier) Finch & Westerholm (Napier) EA Williams (Napier)
1932
District Plan Heritage Group
17
Napier City District Plan Section
1932
NZ Historic Places Trust Classification
Approximate Date of Original Construction
Holder Bros.
Storeys (in approx height)
Builder (PostEQ Reconstr. if Applicable)
Stanley Fern
Structure Type
Architect (PostEQ Reconstr.if Applicable)
134 Hastings Street
Construction Type Notes
Street Address
Enclosed Building
Style
Structure Type
Existing
Approximate Date of Demolition
2012 Status
67
Approximate Date of Reconstruction
Name of Building
n/a
NZ Historic Places Trust Registration #
102
Napier City District Plan Heritage Reference #
16
Jessica's Design Store (Former Bestalls Building)
Art Deco Trust Inventory #
Art Deco Trust Walking Tour Brochure #
Appendix D. Register of Art Deco buildings in Napier, New Zealand
Art Deco
reinforced concrete
RC
1
n/a
City of Napier, Appendix 13
1
City of Napier, Appendix 13
1
reinforced concrete frame
City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13
1
1
2
1
1
1
Spanish Mission
reinforced concrete
RC
2
1
1931
American Renaissance
Steel frame, reinforced concrete
RC
2
1
A Bryan
1933
American Renaissance
RC
2
n/a
Not Recorded
1932
Spanish Renaissance
RC and brick
RC
2
n/a
WM Angus Ltd
1929
Spanish Mission
RC and brick
RC
2
1
reinforced concrete, nickel-plated joinery
RC
2
2
City of Napier, Appendix 13
1
1932
1
1
1
1
1
31
87
1169
26
Ringland's Building
Existing
Enclosed Building
29 Hastings Street
Finch & Westerholm (Napier)
A Boyer
1932
Art Deco
32
85
n/a
n/a
Barry Bros. Building
Existing
Enclosed Building
21 Hastings Street
Finch & Westerholm (Napier)
AB Davis & Sons Ltd
1936
Art Deco
RC
2
n/a
City of Napier, Appendix 13
1
33
6
2805
29
Former Ministry of Works (Former Government Building)
Existing
Enclosed Building
21-23 Browning Street
JT Mair (Wellington)
Not Recorded
1938
Stripped Classical
RC
2
2
City of Napier, Appendix 13
1
267
Napier City District Plan Heritage Reference #
NZ Historic Places Trust Registration #
Art Deco Trust Walking Tour Brochure #
Name of Building
2012 Status
Structure Type
Street Address
Architect (PostEQ Reconstr.if Applicable)
Builder (PostEQ Reconstr. if Applicable)
Approximate Date of Original Construction
34
7
2795
28
Napier Telephone Exchange
Existing
Enclosed Building
35 Browning Street
JT Mair (Wellington)
Not Recorded
1937
35
5
4820
33
County Hotel (Former County Council Offices)
Existing
Enclosed Building
12 Browning Street
Finch & Pufflette
Not Recorded
1908
36
112
2794
34
Existing
Enclosed Building
9 Herschell Street & 3 Tennyson Street
JA Louis Hay (Napier)
Angus Constructi on
1936
Chicago School / Prairie
37
156
1163
38
Existing
Enclosed Building
7 Tennyson Street
JA Louis Hay (Napier)
N Cole
1932
Art Deco
38
161
n/a
n/a
McGlashan's Building
Existing
Enclosed Building
39 Tennyson Street
Finch & Westerholm (Napier)
AB Davis
1932
Spanish Mission
39
162
n/a
17
Former Macky, Logan & Caldwell Building
Existing
Enclosed Building
47 Tennyson Street
EA Williams (Napier)
Burlington Bros. & McMillan
1935
Art Deco
40
160
1129
16
Daily Telegraph Building
Existing
Enclosed Building
49 Tennyson Street
EA Williams (Napier)
Fletcher Constructi on Co.
1932
Art Deco
41
166
4816
14
Munster Chambers
Existing
Enclosed Building
59 Tennyson Street
JA Louis Hay (Napier)
Curtlett Constructi on Co.
1933
Art Deco
42
167
2810
13
Existing
Enclosed Building
61 Tennyson Street
Finch & Westerholm (Napier)
Burlington Bros. & McMillan
1932
Italian Renaissance
43
168
4815
12
Existing
Enclosed Building
65 Tennyson Street
EA Williams (Napier)
Fox & Hillen
1932
44
169
4814
7
Scinde Building
Existing
Enclosed Building
71 Tennyson Street
EA Williams (Napier)
Bull Bros.
Existing
Enclosed Building
79 Tennyson Street
Finch & Westerholm (Napier)
Existing
Enclosed Building
119 Tennyson Street
JT Watson (Napier)
6
46
177
4980
2
Municipal Theatre
2
City of Napier, Appendix 13
1
RC
3
2
City of Napier, Appendix 13
1
Not Recorded
2
2
City of Napier, Appendix 13
1
RC
2
2
City of Napier, Appendix 13
1
RC
2
n/a
City of Napier, Appendix 13
1
RC
1
n/a
City of Napier, Appendix 13
1
RC
2
1
City of Napier, Appendix 13
1
RC
1
2
City of Napier, Appendix 13
1
reinforced concrete
RC
2
2
City of Napier, Appendix 13
1
Stripped Classical
reinforced concrete
RC
1
2
City of Napier, Appendix 13
1
1932
Art Deco
reinforced concrete
RC
1
2
WJ Rood
1932
Spanish Mission
reinforced concrete
RC
1
n/a
WM Angus Ltd
1912
Art Deco
RC with timber floors
RC
3
1
268
Art Deco
1935
1937
Classical Revival
Construction Type Notes
2
Style
RC
Approximate Date of Demolition
District Plan Heritage Group
n/a
Napier City District Plan Section
172
NZ Historic Places Trust Classification
45
Former Murray Roberts Building
Storeys (in approx height)
Sainsbury, Logan & Williams Napier Antique Centre (Former Ross & Glendinning Building)
Structure Type
Hawke's Bay Museum & Art Gallery Art Deco Centre (Former Kinross White Building & Former New Zealand Insurance)
Approximate Date of Reconstruction
Art Deco Trust Inventory #
Appendix D. Register of Art Deco buildings in Napier, New Zealand
reinforced conctere and precast panels 2nd oldest reinforced concrete building in area
reinforced concrete
reinforced concrete walls, gable wood tuss roof reinforced concrete, backside is steel frame atop RC columns reinforced concrete front, brick rear reinforced concrete piers & brick panel sides
City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13
1
1
1
163 Tennyson Street
JA Louis Hay (Napier)
Trevor Bros. Ltd
1923
Existing
Enclosed Building
116 Tennyson Street
EA Williams (Napier)
AB Davis & Sons Ltd
1936
Former Fenwick Flats
Existing
Enclosed Building
112 Tennyson Street
Unknown
1933
3
Public Trust Building
Existing
Enclosed Building
100 Tennyson Street
Hyland & Phillips
4813
5
Hildebrandt's Building
Existing
Enclosed Building
18-20 Dalton Street & 90 Tennyson Street
JA Louis Hay (Napier)
AB Davis & Sons Ltd
1933
Art Deco
173
n/a
n/a
Existing
Enclosed Building
86 Tennyson Street
Finch & Westerholm (Napier)
Bull Bros.
1932
Stripped Classical
171
n/a
n/a
Existing
Enclosed Building
76 Tennyson Street
EA Williams (Napier)
Walker & McBeath
1929
49
176
n/a
n/a
50
175
n/a
n/a
51
174
1167
52
24
53
54
Former Deco Centre (Old Fire Station) Canning & Loudoun (Salmon Motors)
Former HB Building & Investment Society Building Former McCulloch Butler & Spence Building
HC Curtlett Constructi on Co. Fletcher Constructi on Co.
1922
1932
1931
1933
2
reinforced concrete
RC
2
2
Art Deco
RC, gable roof timber, and CGI
RC
2
n/a
City of Napier, Appendix 13
1
California Bungalow
brick and RC, roof hipped, conc tile
RC
1
n/a
City of Napier, Appendix 13
1
RC
2
1
City of Napier, Appendix 13
1
RC
1
2
City of Napier, Appendix 13
1
RC
2
n/a
City of Napier, Appendix 13
1
RC
1
n/a
City of Napier, Appendix 13
1
RC
1
n/a
City of Napier, Appendix 13
1
RC
1
n/a
City of Napier, Appendix 13
1
RC
1
2
City of Napier, Appendix 13
1
RC
1
2
City of Napier, Appendix 13
1
Classical Revival
RC with hipped roof
Stripped Classical
55
170
n/a
8
Halsbury Chambers
Existing
Enclosed Building
74 Tennyson Street
JA Louis Hay (Napier)
TG Pedlow
1932
Stripped Classical
56
165
n/a
9
Devon House
Existing
Enclosed Building
58 Tennyson Street
Gummer, Ford, Hoadley & Budge
WM Angus Ltd
1934
Stripped Classical
57
164
4817
10
Tennyson Chambers
Existing
Enclosed Building
54 Tennysons Street
JA Louis Hay (Napier)
HC Curtlett Constructi on Co.
1932
Art Deco
58
163
4818
11
Gladstone Chambers
Existing
Enclosed Building
50 Tennyson Street
Finch & Westerholm (Napier)
Not Recorded
1932
Art Deco
269
reinforced concrete, roof flat concrete reinforced concrete, roof hipped wood frame and CGI
reinforced concrete front, reinforced concrete piers & brick panels, hipped roof timber, CGI wall - RC, roof flat concrete, large steelframed skylights reinforced concrete, gabled roof, timber truss & iron heart rim floors reinforced concrete
Napier City District Plan Section
93
2
Chicago School / Prairie Chicago School / Prairie
Construction Type Notes
1131
Not Recorded
Style
180
District Plan Heritage Group
Approximate Date of Original Construction
Enclosed Building
48
NZ Historic Places Trust Classification
Builder (PostEQ Reconstr. if Applicable)
Existing
n/a
Storeys (in approx height)
Architect (PostEQ Reconstr.if Applicable)
Unk now n
4812, 4811
Structure Type
Street Address
Unknown
179
Approximate Date of Demolition
Structure Type
JA Louis Hay (Napier)
47
Approximate Date of Reconstruction
2012 Status
155-157 Tennyson Street
Art Deco Trust Walking Tour Brochure #
Enclosed Building
NZ Historic Places Trust Registration #
Existing
Napier City District Plan Heritage Reference #
Former Fire Chief's House
Art Deco Trust Inventory #
Name of Building
Appendix D. Register of Art Deco buildings in Napier, New Zealand
City of Napier, Appendix 13 City of Napier, Appendix 13
1
1
n/a
63
47
n/a
n/a
64
50
4824
76
Olympic Properties (1936) Olympic Properties (1949) Smith & Chambers Building
Approximate Date of Demolition
District Plan Heritage Group
2809
Napier City District Plan Section
48
1932
NZ Historic Places Trust Classification
62
Hawke's Bay Chambers
Burlington Bros. & McMillan
Storeys (in approx height)
74
JA Louis Hay (Napier)
Structure Type
4823
36-40 Tennyson Street & 1-7 Market Street
Construction Type Notes
45
Enclosed Building
1932
Style
61
Existing
Suburban Land and Constructi on Co.
Approximate Date of Reconstruction
Bowman's Building
42 Tennyson Street
Finch & Westerholm (Napier)
Approximate Date of Original Construction
72
Builder (PostEQ Reconstr. if Applicable)
4819
Enclosed Building
Architect (PostEQ Reconstr.if Applicable)
158
Existing
Street Address
60
Structure Type
15
2012 Status
Name of Building
1172
NZ Historic Places Trust Registration #
159
Napier City District Plan Heritage Reference #
59
The Former Kaiapoi Building (State Insurance)
Art Deco Trust Inventory #
Art Deco Trust Walking Tour Brochure #
Appendix D. Register of Art Deco buildings in Napier, New Zealand
Stripped Classical
brick & reinforced concrete, gable roof, steel wood truss & CGI, concrete floors
RC
2
2
City of Napier, Appendix 13
1
Chicago School / Prairie
reinforced concrete
RC
2
2
City of Napier, Appendix 13
1
RC
2
2
City of Napier, Appendix 13
1
Existing
Enclosed Building
78-82 Emerson Street
EA Williams (Napier)
Holder Bros.
1932
Art Deco
reinforced concrete, hipped roof of timber and iron
Existing
Enclosed Building
112 Emerson Street
JA Louis Hay (Napier)
Not Recorded
1936
Spanish Mission
RC with flat roof of concrete
RC
2
2
Existing
Enclosed Building
116-118 Emerson Street
JT Watson (Napier)
WL Atherfold
1949
Plain
RC with flat and hipped roof
RC
2
n/a
Existing
Enclosed Building
122-132 Emerson Street
Alred Hill (Napier)
Fletcher Constructi on Co.
1932
Art Deco
reinforced concrete
RC
2
2
JJ Lee
1933
Stripped Classical
RC
1
n/a
RC
1
2
RC
2
n/a
RC
1
n/a
65
53
n/a
n/a
JS Golding
Existing
Enclosed Building
134 Emerson Street
Finch & Westerholm (Napier)
66
55
4826
77
The Self-Help Shoppers Fair Building
Existing
Enclosed Building
144 Emerson Street
JA Louis Hay (Napier)
Reid Bros.
1932
Art Deco
67
56
n/a
n/a
Gallate's
Existing
Enclosed Building
148 Emerson Street
JA Louis Hay (Napier)
Holder Bros.
1932
Art Deco
68
58
n/a
n/a
Readings Building
Existing
Enclosed Building
156 Emerson Street
Unknown
Not Recorded
Unk now n
Art Deco
69
59
4827
78
Briasco's Building
Existing
Enclosed Building
162 Emerson Street
EA Williams (Napier)
WM Angus Ltd
1930
1932
RC with hipped roof of timber and CGI RC with hipped roof of timber and iron brick and reinforced concrete with hipped roof of timber and CGI
City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13
1
1
1
1
1
1
1
Stripped Classical
reinforced concrete
RC
2
2
reinforced concrete, with washroom on flat concrete roof
RC
2
2
City of Napier, Appendix 13
1
RC
2
2
City of Napier, Appendix 13
1
1
70
61
4828
79
Kidsons Building
Existing
Enclosed Building
170-172 Emerson Street & 26-28 Dalton Street
Alred Hill (Napier)
Holder Bros.
1933
Art Deco
71
62
1157
n/a
Napier Building
Existing
Enclosed Building
174-180 Emerson Street
Finch & Westerholm (Napier)
JJ Lee
1933
Stripped Classical
Existing
Enclosed Building
182 Emerson Street
HJ Doherty
BE Bartlett
1933
Art Deco
RC with hipped roof of timber and iron
RC
1
n/a
City of Napier, Appendix 13
1
Existing
Enclosed Building
190 Emerson Street
Finch & Westerholm (Napier)
H Faulknor
1935
Spanish Mission
RC with hipped & gable roof, timber & iron
RC
2
2
City of Napier, Appendix 13
1
72
63
n/a
n/a
Burtons Building (Boston Building)
73
64
4830
n/a
CE Rogers (190 Emerson)
270
65
n/a
n/a
Fenwick Building
Existing
Enclosed Building
196 Emerson Street
EA Williams (Napier)
75
66
n/a
n/a
King Building
Existing
Enclosed Building
202 Emerson Street
AB Davis & Sons (Napier)
76
68
n/a
n/a
Singer Building
Existing
Enclosed Building
208 Emerson Street
JA Louis Hay (Napier)
77
69
n/a
86
Colenso House (Colenso Chambers)
Existing
Enclosed Building
210-222 Emerson Street
EA Williams (Napier)
78
70
n/a
n/a
Hope Building
Existing
Enclosed Building
226 Emerson Street
Existing
Enclosed Building
232-234 Emerson Street
79
71
n/a
n/a
Neo-Norman
1932
Art Deco
1932
Art Deco
Holder Bros.
1932
Art Deco
Holder Bros.
1932
Spanish Mission
R Northe & Sons
1933
Spanish Mission
R Northe & Sons
1921
HC Curtlett Constructi on Co. AB Davis & Sons Ltd
1932
Art Deco
Existing
Enclosed Building
242-246 Emerson Street
HJ Doherty
Holder Bros.
1932
Art Deco
The Provincial Hotel
Existing
Enclosed Building
256-262 Emerson Street
Finch & Westerholm (Napier)
Holder Bros.
1932
Spanish Mission
n/a
Concord House
Existing
Enclosed Building
269-279 Emerson Street
Unknown
Not Recorded
1934
Art Deco
n/a
n/a
Methodist Trustees Building
Existing
Enclosed Building
251A Emerson Street
Finch & Westerholm (Napier)
WJ Rood
1932
Spanish Mission
74
n/a
n/a
Boylands
Existing
Enclosed Building
245-247 Emerson Street
Finch & Westerholm (Napier)
Holder Bros.
1932
Spanish Mission
73
n/a
87
Loo Kee Building (Loo Kee & Co.)
Existing
Enclosed Building
239 Emerson Street
JT Watson (Napier)
AB Davis & Sons Ltd
1940
Art Deco
85
Mid City Plaza Building (205 Emerson, Former Hawke's Bay Farmers' Coop)
Existing
Enclosed Building
205 Emerson Street
EA Williams (Napier)
SJ Crabbe 1933
Art Deco
80
72
n/a
n/a
81
75
1166
90
82
77
n/a
83
76
84
85
86
Northe & Sons (Shanghai Building) Former Stevens Building (Sangs Building)
Finch & Westerholm (Napier) Finch & Westerholm (Napier)
1940
67
n/a
271
RC with hipped & gable roof, timber & iron RC piers and brick panels, hipped flat roof, concrete floor RC with hipped roof, concrete floors RC with gable roof - timber and iron, concrete floors reinforced concrete, iron roof RC piers and brick panels, concrete floors RC with flat concrete roof RC, lean-to roof iron, concrete floors RC with hipped roof, timber and CGI RC front, RC and brick panels, timber floor RC with gable roof - timber and iron RC front and piers, brick panels, hipped flat roof reinforced concrete front, reinforced concrete piers & brick panels
reinforced concrete
District Plan Heritage Group
74
WL Atherfold
Napier City District Plan Section
Finch & Westerholm (Napier)
NZ Historic Places Trust Classification
Architect (PostEQ Reconstr.if Applicable)
108 Tennysons Street
Storeys (in approx height)
Street Address
Enclosed Building
Structure Type
Structure Type
Existing
Construction Type Notes
2012 Status
CE Rogers (108 Tennyson)
Style
Name of Building
n/a
Approximate Date of Demolition
Art Deco Trust Walking Tour Brochure #
4830
Approximate Date of Reconstruction
NZ Historic Places Trust Registration #
64
Approximate Date of Original Construction
Napier City District Plan Heritage Reference #
73
Builder (PostEQ Reconstr. if Applicable)
Art Deco Trust Inventory #
Appendix D. Register of Art Deco buildings in Napier, New Zealand
RC
3
2
City of Napier, Appendix 13
1
RC
2
n/a
City of Napier, Appendix 13
1
RC
2
n/a
City of Napier, Appendix 13
1
RC
1
n/a
City of Napier, Appendix 13
1
RC
2
n/a
RC
1
n/a
RC
2
n/a
RC
1
n/a
RC
1
2
RC
1
n/a
City of Napier, Appendix 13
1
RC
1
n/a
City of Napier, Appendix 13
1
RC
2
n/a
City of Napier, Appendix 13
1
RC
2
n/a
City of Napier, Appendix 13
1
RC
1
n/a
City of Napier, Appendix 13
1
City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13
1
1
1
1
1
80
Former Hotel Central
Existing
Enclosed Building
47-61 Dalton Street & 183187 Emerson Street
EA Williams (Napier)
H Faulknor
88
28
n/a
n/a
CB Hansen Building
Existing
Enclosed Building
73-81 Dalton Street
Finch & Westerholm (Napier)
89
27
1155
84
Masson House
Existing
Enclosed Building
66-82 Dalton Street
90
26
n/a
n/a
CD Cox
Existing
Enclosed Building
91
60
n/a
n/a
Welsford's
Existing
92
57
n/a
n/a
Lockyer's
93
54
n/a
n/a
Rice's Building
reinforced concrete
RC
2
n/a
City of Napier, Appendix 13
1
1932
Art Deco
RC with flat concrete roof
RC
3
1
City of Napier, Appendix 13
1
JJ Lee
1933
Art Deco
RC front, piers, and brick panels
RC
2
n/a
EA Williams (Napier)
WM Angus Ltd
1932
Art Deco
reinforced concrete
RC
2
2
58 Dalton Street
JA Louis Hay (Napier)
EF Ferguson
1926
RC
2
n/a
Enclosed Building
157-161 Emerson Street
Natusch & Sons (Napier)
Reid Bros.
1932
Art Deco
RC front, RC and brick
RC
1
n/a
Existing
Enclosed Building
153-155 Emerson Street
Natusch & Sons (Napier)
WM Angus Ltd
1932
Art Deco
RC, flat roof of concrete
RC
2
n/a
Existing
Enclosed Building
143-147 Emerson Street
Stripped Classical
RC and brick, gable roof, corrugated iron
RC
2
n/a
RC
1
2
RC
2
n/a
RC
1
n/a
City of Napier, Appendix 13
1
RC
2
n/a
City of Napier, Appendix 13
1
RC
2
2
City of Napier, Appendix 13
1
RC
1
n/a
City of Napier, Appendix 13
1
SJ Crabbe 1920
1932
1934
Approximate Date of Demolition
Art Deco
Builder (PostEQ Reconstr. if Applicable)
District Plan Heritage Group
1114
Napier City District Plan Section
25
NZ Historic Places Trust Classification
87
Storeys (in approx height)
EA Williams (Napier)
Structure Type
Architect (PostEQ Reconstr.if Applicable)
123-141 Dickens Street
Construction Type Notes
Street Address
Enclosed Building
Style
Structure Type
Existing
Approximate Date of Reconstruction
2012 Status
85
Approximate Date of Original Construction
Name of Building
n/a
NZ Historic Places Trust Registration #
67
Napier City District Plan Heritage Reference #
86
Mid City Plaza Building (123141 Dickens, Former Hawke's Bay Farmers' Coop)
Art Deco Trust Inventory #
Art Deco Trust Walking Tour Brochure #
Appendix D. Register of Art Deco buildings in Napier, New Zealand
Not Recorded
Finch & Westerholm (Napier) Finch & Westerholm (Napier) Finch & Westerholm (Napier)
Not Recorded
1929
JH Williams & Co.
1932
Not Recorded
L Thomas
1932
Art Deco
1932
94
52
4825
n/a
Former Triggs & Morgan Building
Existing
Enclosed Building
131 Emerson Street
95
51
n/a
75
Hurst's Building
Existing
Enclosed Building
125 Emerson Street
96
49
n/a
n/a
Clausens Building
Existing
Enclosed Building
105-111 Emerson Street
Finch & Westerholm (Napier)
Burlington Bros. & McMillan
1932
97
46
n/a
n/a
Emerson Building
Existing
Enclosed Building
93 Emerson Street
Finch & Westerholm (Napier)
Not Recorded
1931
Spanish Mission
98
44
2803
73
McGruers Building
Existing
Enclosed Building
67-91 Emerson Street
Natusch & Sons (Napier)
WM Angus Ltd
1932
Spanish Mission
99
43
n/a
70
Hannahs Building
Existing
Enclosed Building
49 Emerson Street
EA Williams (Napier)
Holder Bros.
1933
Spanish Renaissance
272
1955
Spanish Mission
RC, hipped roof at front RC front, RC and brick panels, hipped roof - timber and iron RC, hipped roof of timber and iron reinforced concrete front, reinforced concrete & brick panels, flat roof, concrete floors RC, hipped roof
City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13
1
1
1
1
1
1
1
1
Napier City District Plan Heritage Reference #
NZ Historic Places Trust Registration #
Art Deco Trust Walking Tour Brochure #
Name of Building
2012 Status
Structure Type
Street Address
Architect (PostEQ Reconstr.if Applicable)
Builder (PostEQ Reconstr. if Applicable)
Approximate Date of Original Construction
Style
100
41
183
56
T & G Building
Existing
Enclosed Building
1 Emerson Street
Atkin & Mitchell (Wellington)
WM Angus Ltd
1936
Stripped Classical
101
36
1130
83
Broadcasting House (Former Dalgety's Building)
Existing
Enclosed Building
105 Dickens Street
EA Williams (Napier)
Not Recorded
1926
102
30
n/a
n/a
HB Farmers Garage
Existing
Enclosed Building
97 Dalton Street
EA Williams (Napier)
SJ Crabbe 1931
103
14
n/a
n/a
Waterworths
Existing
Enclosed Building
54 Clive Square East
Finch & Westerholm (Napier)
Building Constructi on Co.
Existing
Enclosed Building
110 Dickens Street
Finch & Westerholm (Napier)
Structure Type
Storeys (in approx height)
NZ Historic Places Trust Classification
Napier City District Plan Section
District Plan Heritage Group
RC, flat roof, concrete
RC
3
1
City of Napier, Appendix 13
1
Stripped Classical
RC
2
2
City of Napier, Appendix 13
1
Streamline Moderne
RC
1
n/a
1934
Not Recorded
RC
1
n/a
Not Recorded
1932
Spanish Mission
reinforced concrete
RC
2
2
City of Napier, Appendix 13
1
1938
Approximate Date of Demolition
Construction Type Notes
Approximate Date of Reconstruction
Art Deco Trust Inventory #
Appendix D. Register of Art Deco buildings in Napier, New Zealand
City of Napier, Appendix 13 City of Napier, Appendix 13
1
1
104
37
2812
82
Former State Cinema (Former State Theatre)
105
31
n/a
n/a
Chisholm Building
Existing
Enclosed Building
128 Dalton Street
EA Williams (Napier)
JW Fox and Co.
1931
Not Recorded
RC and brick
RC
1
n/a
City of Napier, Appendix 13
1
106
34
2811
81
Former Gaiety De Luxe Cinema (Former Gaiety Theatre)
Existing
Enclosed Building
88-94 Dickens Street
Finch & Westerholm (Napier)
Holder Bros.
1931
Spanish Mission
reinforced concrete
RC
2
2
City of Napier, Appendix 13
1
107
to be listed
n/a
n/a
Eames Building
Existing
Enclosed Building
44 Dickens Street
JT Watson (Napier)
WL Atherfold
1945
Art Deco
RC
1
n/a
108
33
4832
n/a
Golden Crown
Existing
Enclosed Building
38 Dickens Street
Unknown
Not Recorded
Unk now n
Spanish Mission
RC
2
2
Existing
Enclosed Building
14 Herschell Street
LG Williams
AB Davis & Sons Ltd
1939
International
RC
2
2
109
114
1106
35
Archie's Bunker Backpackers (Former Automobile Association Building)
110
140
n/a
n/a
Taradale Town Hall
Existing
Enclosed Building
8 Meeanee Road
EA Williams (Napier)
George H Wilson
1932
Art Deco
RC
1
n/a
111
80
n/a
n/a
Taradale Hotel (McDonald's)
Existing
Enclosed Building
330 Gloucester
EA Williams (Napier)
Not Recorded
1931
Spanish Mission
RC
1
n/a
112
n/a
n/a
n/a
Crown Hotel
Existing
Enclosed Building
22 Waghorne Street
EA Williams (Napier)
HC Curtlett Constructi on Co.
1932
Spanish Mission
RC and brick, roof, tile
RC
2
n/a
113
n/a
n/a
n/a
Union Hotel
Existing
Enclosed Building
3 Waghorne Street
Edmund Anscombe (Hastings)
WM Angus Ltd
1931
Art Deco
RC and brick
RC
2
n/a
273
reinforced concrete front cavity brick & reinforced concrete, hipped roof
City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Appendix 13 City of Napier, Ahuriri Section, Appendix to Sect. 17 City of Napier, Ahuriri Section, Appendix to Sect. 17
to be listed 1
2
1
1
2
2
114
n/a
n/a
n/a
115
n/a
1170
n/a
116
12
1180
92
117
n/a
n/a
n/a
118
n/a
n/a
n/a
119
n/a
n/a
45
Richardson's Building
Rothman's Building (Former National Tobacco Co. Building) The Community Centre (Former Women's Rest) Cathedral Lane Academy Former Hector McGregor's Building Former Soldiers' Club (Former Napier Spa)
Existing
Enclosed Building
46 Bridge Steet
Natusch & Sons (Napier)
Not Recorded
1932
Art Deco
Existing
Enclosed Building
1 Ossian Street
JA Louis Hay (Napier)
H Faulknor
1933
Chicago School / Prairie
Existing
Enclosed Building
5 Clive Square East
JA Louis Hay (Napier)
Not Recorded
1925
Existing
Enclosed Building
11 Cathedral Lane
WL Atherfold
WL Atherfold
1939
Art Deco
Unk now n
1
2
Timber Frame
2
n/a
n/a
n/a
Not Recorded
Not Recorded
2
n/a
n/a
n/a
Not Recorded
2
n/a
n/a
n/a
1
Existing
Unknown
Existing
Enclosed Building
39 Marine Parade
JA Louis Hay (Napier)
Not Recorded
1920
Chicago School / Prairie
Existing
Enclosed Building
60 West Quay
Edmund Anscombe (Hastings)
Not Recorded
Unk now n
Stripped Classical
2
2
n/a
Not Recorded
2
n/a
n/a
n/a
RC and Timber
1
n/a
n/a
n/a
three arches in Veronica Sunbay/plaza
RC
1
2
City of Napier, Appendix 13
1
Not Recorded
theater/stage area in plaza
RC
2
2
City of Napier, Appendix 13
1
Art Deco
building demolished in 2012, façade retainted for incorporation into new development
Steel Frame and RC
2
n/a
City of Napier, Appendix 13
1
122
n/a
n/a
n/a
Ranui Flats
Existing
Enclosed Building
541 Marine Parade
William John Green & A Garnett
Mr Butcher
1938
Streamline Moderne
123
n/a
n/a
42
Hogs Breath Café (Former Napier Club)
Existing
Enclosed Building
49 Marine Parade
EA Williams (Napier)
Walker & McBeath
1933
Spanish Mission
n/a
123
2807
52
The Colonnade (New Napier Arch)
Existing
Marine Parade
JT Watson (Napier)
Not Recorded
1936
Art Deco
n/a
131
4822
53
The Soundshell
Existing
70 Marine Parade
JT Watson (Napier)
Not Recorded
1935
65
Former Odeon Theatre (Former Plaza Theatre, Façade remains as part of Farmer's Dept. Store)
142 Hastings Street
Llewelyn & William (Wellington)
Fletcher Constructi on Co.
2012
timber frame with plaster
1
RC
n/a
274
RC with acetone welded steel frame
City of Napier, Ahuriri Section, Appendix to Sect. 17
n/a
1932
District Plan Heritage Group
Not Recorded
Not Recorded
Enclosed Building
Napier City District Plan Section
1
105 Marine Parade
Demolishe d
NZ Historic Places Trust Classification
1
n/a
n/a
Storeys (in approx height)
Steel Frame and RC
120
104
Structure Type
n/a
New Zealand Shipping Co Builting Ltd
18
to be listed
1
Chicago School / Prairie
1925
City of Napier, Ahuriri Section, Appendix to Sect. 17 City of Napier, Ahuriri Section, Appendix to Sect. 17 City of Napier, Appendix 13
RC
Enclosed Building
Partially Enclosed or Open Structure Partially Enclosed or Open Structure
Construction Type Notes
Style
Approximate Date of Demolition
Approximate Date of Reconstruction
Approximate Date of Original Construction
Builder (PostEQ Reconstr. if Applicable)
Architect (PostEQ Reconstr.if Applicable)
Street Address
Structure Type
2012 Status
Name of Building
Art Deco Trust Walking Tour Brochure #
NZ Historic Places Trust Registration #
Napier City District Plan Heritage Reference #
Art Deco Trust Inventory #
Appendix D. Register of Art Deco buildings in Napier, New Zealand
Concrete exterior with Rimu and Matai interior RC and timber with corrugated iron roof
121
n/a
n/a
n/a
A
n/a
n/a
n/a
South British Insurance
Demolishe d
Enclosed Building
11 Browning Street
EA Williams (Napier)
Demolishe d
Enclosed Building
90 Hastings Street
Atkin & Mitchell (Wellington)
Demolishe d
Enclosed Building
90 Hastings Street
Atkin & Mitchell (Wellington)
Demolishe d
Enclosed Building
114 Hastings Street
Stanley Fern
Demolishe d Demolishe d Demolishe d
Enclosed Building Enclosed Building Enclosed Building
126 Hastings Street 174 Hastings Street 176 Hastings Street
B
n/a
n/a
n/a
Norwich Union Insurance
C
n/a
n/a
68
National Bank of NZ
D
n/a
n/a
n/a
E
n/a
n/a
n/a
F G H
n/a n/a n/a
n/a n/a n/a
n/a n/a n/a
Commercial Bank of Australia Henry Williams Ltd. Napier Gas Company Smith Building ANZ Building
Demolishe d
Enclosed Building
105 Hastings Street
Burlington Bros. & McMillan Totterdell Ltd. Fletcher Constructi on Co. Not Recorded
Unknown EA Williams (Napier) Alred Hill (Napier) Swan, Lawrence & Swan (Wellington)
Not Recorded Not Recorded WM Angus Ltd Trevor Bros. Ltd
n/a
n/a
n/a
1932
1983
RC
2
n/a
n/a
n/a
1933
1983
Stripped Classical
RC
2
n/a
n/a
n/a
1932
1961
Stripped Classical
RC
2
n/a
n/a
n/a
1933
1985
Art Deco
RC
1
n/a
n/a
n/a
1932
1988
Art Deco
RC
1
n/a
n/a
n/a
1932
post1975
Not Recorded
RC
1
n/a
n/a
n/a
Classical Revival
Steel Frame and RC
2
n/a
n/a
n/a
RC
1
n/a
n/a
n/a
RC
2
n/a
n/a
n/a
RC
3
n/a
n/a
n/a
1933
Not Recorded
Unk now n
J
n/a
n/a
n/a
UFS Dispensary
Demolishe d
Enclosed Building
265 Emerson Street
Finch & Westerholm (Napier)
George H Wilson
1932
EA Williams (Napier)
Holder Bros.
1929
n/a
n/a
n/a
Peach's Garage
Demolishe d
Enclosed Building
Demolishe d
Enclosed Building
141 Emerson Street
Natusch & Sons (Napier)
57 Dickens Street
JA Louis Hay (Napier)
M
n/a
n/a
n/a
Simmonds Building
N
n/a
n/a
n/a
Anderson & Hansen Motors
Demolishe d
Enclosed Building
n/a
n/a
n/a
4
St Paul's Hall (1931-1951)
Demolishe d
Enclosed Building
89 Tennyson Street
Unknown
JA Louis Hay (Napier)
Not Recorded Burlington Bros. & McMillan Curtlett Constructi on Co. Not Recorded
275
District Plan Heritage Group
2
Unknown
L
Approximate Date of Demolition
RC
104 Tennyson Street
Enclosed Building
Approximate Date of Reconstruction
Art Deco Classical Revival
Enclosed Building
Demolishe d
1
1975
1933
Demolishe d
E & D Building
City of Napier, Appendix 13
n/a
Canning, Loudon & Derry
n/a
n/a
2
n/a
n/a
1
RC
1994
n/a
n/a
RC
Art Deco
1933
n/a
K
Art Deco
building demolished in 2012, façade retainted for incorporation into new development
City of Napier, Ahuriri Section, Appendix to Sect. 17
I
167 Emerson Street & 46 Dalton Street 21 Dickens Street
Napier City District Plan Section
Not Recorded
NZ Historic Places Trust Classification
1 Barry Street
JA Louis Hay (Napier)
2012
Storeys (in approx height)
Enclosed Building
Ellison & Duncan (Façade remains but originally faced Union Street)
1932
Structure Type
Unknown
Construction Type Notes
Unknown
Style
158 Hastings Street
Approximate Date of Original Construction
Demolishe d
Builder (PostEQ Reconstr. if Applicable)
Enclosed Building
Architect (PostEQ Reconstr.if Applicable)
Demolishe d
Street Address
Structure Type
64
Callinicos Building (Façade remains as part of Farmer's Dept. Store)
2012 Status
NZ Historic Places Trust Registration # n/a
Name of Building
106
Art Deco Trust Walking Tour Brochure #
19
Napier City District Plan Heritage Reference #
Art Deco Trust Inventory #
Appendix D. Register of Art Deco buildings in Napier, New Zealand
1985
demolished in 1983
RC and brick, flat roof
RC and brick with steel frame walls - brick and RC, roof gabled with CGI RC front, RC piers ande brick panels
2
1971
Not Recorded
1986
Spanish Mission
1983
Not Recorded
1929
1993
Art Deco
RC
2
n/a
n/a
n/a
1932
post1974
Not Recorded
RC
2
n/a
n/a
n/a
1932
Unkno wn
Spanish Mission
RC
2
n/a
n/a
n/a
1931
1951
Neo-Gothic
Masonry
3
n/a
n/a
n/a
1931
1932
RC faced with brick
brick foundations and walls
Builder (PostEQ Reconstr. if Applicable)
Approximate Date of Original Construction
Unknown
Not Recorded
1888
n/a
n/a
n/a
51
Veronica Sunbay (19341991)
Demolishe d
Partially Enclosed or Open Structure
Marine Parade
JT Watson (Napier)
Not Recorded
1934
O
n/a
n/a
n/a
Stewart Greer Motors
Demolishe d
Enclosed Building
81 Dickens Street
JA Louis Hay (Napier)
Not Recorded
P
n/a
n/a
n/a
HB Electric Power Board
Demolishe d
Enclosed Building
173 Dickens Street
EA Williams (Napier)
Enclosed Building
98 Dickens Street
Natusch & Sons (Napier)
Enclosed Building
28 Dickens Street
EA Williams (Napier)
Q
n/a
n/a
n/a
Ozone Building
Demolishe d
R
n/a
n/a
n/a
Sargood, Son & Ewen
Demolishe d
Unk now n Unk now n
1932
1965
Not Recorded
1991
Classical Revival
Unkno wn
Art Deco
1993
District Plan Heritage Group
Architect (PostEQ Reconstr.if Applicable)
28 Browning Street
Napier City District Plan Section
Street Address
Enclosed Building
NZ Historic Places Trust Classification
Structure Type
Demolishe d
Storeys (in approx height)
2012 Status
St. John's Cathedral (1932-1965)
Structure Type
Name of Building
27
Timber Frame
Unknown
n/a
n/a
n/a
plaza/open area near gardens
RC
1
n/a
n/a
n/a
RC and brick
RC
2
n/a
n/a
n/a
Not Recorded
RC
2
n/a
n/a
n/a
RC
2
n/a
n/a
n/a
RC
2
n/a
n/a
n/a
Construction Type Notes
Art Deco Trust Walking Tour Brochure #
n/a
Style
NZ Historic Places Trust Registration #
n/a
Approximate Date of Demolition
Napier City District Plan Heritage Reference #
n/a
Approximate Date of Reconstruction
Art Deco Trust Inventory #
Appendix D. Register of Art Deco buildings in Napier, New Zealand
Fletcher Constructi on Co. Not Recorded Fletcher Constructi on Co.
1915
1931
1989
Not Recorded
1931
1931
post1975
Not Recorded
JT Watson (Napier)
WJ Rood
1938
1990
Streamline Moderne
plastered timber
Timber Frame
1
n/a
n/a
n/a
1931
S
n/a
n/a
n/a
Thackeray House
Demolishe d
Enclosed Building
Corner of Dickens Street & Munroe Street
T
n/a
n/a
n/a
Gospel Hall
Demolishe d
Enclosed Building
5 Carlyle Street
Unknown
Not Recorded
Unk now n
1997
Art Deco
plastered timber
Timber Frame
1
n/a
n/a
n/a
U
n/a
n/a
n/a
Williams & Kettle Building
Demolishe d
Enclosed Building
13 Browning Street
Unknown
Not Recorded
1932
1975
Art Deco
Exterior had a grey cement finish
Not Recorded
1
n/a
n/a
n/a
Enclosed Building Enclosed Building
96 Emerson Street 225 Emerson Street
1933
1965
Not Recorded
2
n/a
n/a
n/a
1932
post1980
Art Deco
Unknown
n/a
n/a
n/a
Enclosed Building
1933
Unkno wn
Not Recorded
1
n/a
n/a
n/a
V W X
n/a n/a n/a
n/a n/a n/a
n/a
Mayfair Theatre
n/a
Cosmopolitan Club
Demolishe d Demolishe d
n/a
Dalton Chambers
Demolishe d
93 Dalton Street
Unknown EA Williams (Napier) Finch & Westerholm (Napier)
Not Recorded Not Recorded H Corridas
276
Not Recorded Not Recorded RC, hipped roof of timber and iron
RC
Appendix E. Displacement-based RC column assessment for a case study interwar building
Appendix E. Displacement-based RC column assessment for a case study interwar building Following the devastating 1931 Hawke‘s Bay earthquake, commercial buildings in the Hawke‘s Bay, New Zealand region were rebuilt in mostly homogenous structural and architectural styles. Most were constructed of reinforced concrete (RC) two-way space frames in the Art Deco aesthetic popularised during the interwar time period. Although most Art Deco RC columns in Hawke‘s Bay have generally ductile detailing for their time period of construction, they are nonetheless often expected to be brittle, earthquake-prone components based on strength-based seismic assessments. The reported case study was intended to provide a displacement-based example for undertaking a seismic assessment of Art Deco RC columns while appropriately accounting for regional seismicity, material properties, building component interaction, column geometry, and reinforcement detailing, as a resource for professional structural engineers tasked with seismic assessments and retrofit designs for similar buildings.
E.1. Introduction Art Deco buildings are of immense value to the cultural and civic heritage of the Hawke‘s Bay community. However, a lack of understanding of the expected performance of these buildings in an earthquake threatens their continued utility. Past engineering assessments of these ostensibly brittle reinforced concrete (RC) low-rise buildings have resulted in predictions of generally poor seismic performance (e.g., van de Vorstenbosch et al. 2002), contrary to the empirical evidence from the 1931 Hawke‘s Bay earthquake (Mitchell 1931; Brodie and Harris 1933) and empirical evidence from other historical earthquakes in New Zealand (Dowrick and Rhoades 2000). These buildings are now threatened with forced vacancy or demolition by legislation (New Zealand Parliament 2004, 2005) dependent on their estimated seismic capacities. As a result, other researchers have called for more sophisticated studies into the seismic capacities of Art Deco buildings in Hawke‘s Bay (Dowrick 2006). Walsh et al. (2014) carried out a geometric study of Hawke‘s Bay‘s Art Deco buildings and performed a pushover capacity assessment of several RC ground storey columns within a representative sample of Art Deco buildings. Compared to the buildings considered by Walsh 277
Appendix E. Displacement-based RC column assessment for a case study interwar building
et al. (2014), the Information Management Services (IMS) building in Hastings has a relatively low ratio of the sum of RC column and wall cross-sectional areas on the ground floor to the total building footprint area, or ―structural footprint‖ ratio, of only 0.6%. Furthermore and as will be demonstrated herein, the typical ground storey column of the IMS Hastings building was estimated to have a relatively high ratio of shear demand at plastic hinging to nominal shear capacity, Vp / Vn , and would be deemed in accordance with the criteria of the American Society of Civil Engineers (ASCE 2014) to be likely to experience an undesirable shear-controlled failure under lateral loading. However, despite these disadvantages, this particular building survived the 1931 Hawke‘s Bay earthquake with only superficial damage, making it an appropriate case study building in the following displacement-based assessment.
E.2. The case study building The IMS Hastings building was constructed by the Hawke‘s Bay Farmers Co-operative Association (HBFCA) in 1929 to replace the building on the same site that had been destroyed by a fire. It was designed by Wellington architect Edmund Anscombe & Associates and survived the 3 February 1931 Hawke‘s Bay earthquake with little observable structural damage (NZHPT 2013) despite the high local intensities (>MM9) and in contrast to the extensive damage to many neighbouring buildings caused by the earthquake (Dowrick 1998). The IMS Hastings building is three storeys in height above grade, and it has a basement that comprises approximately half of the building footprint which is approximately 30 m x 36 m. The building‘s support structure is comprised of multiple bays of RC columns typically spaced at 6 m x 6 m. The columns are octagonal in cross-section with an effectively equivalent circular cross-sectional diameter of 447 mm at the ground storey. The tops of the columns taper outward into a thickened slab haunch (i.e., ―drop slab‖ construction) supporting two-way spanning RC floor slabs. RC spandrel beams extend around the exterior of the building at each level. In addition to unreinforced clay brick masonry (URM) infill walls on the exterior of the building, interior URM walls exist in multiple locations throughout the building in addition to two RC lift shafts. An ―uppercroft‖ annex was added to the roof with access from the second storey over a portion of the building footprint. Photographs of the typical exterior and interior arrangement of the building are included in Figure E.1, and additional illustrations and details are included in Appendix F.
278
Appendix E. Displacement-based RC column assessment for a case study interwar building
(a) Southeast elevation of the building
(b) Northwest elevation of the building showing URM infill walls
(c) First storey internal column arrangement
(d) Ground storey internal column arrangment
Figure E.1. Photographs of the IMS Hastings building
E.3. Regional seismicity and performance criteria The aggregated hazard factor, Z , in Hastings of 0.39 is three times the aggregated seismic hazard factor for Auckland (New Zealand‘s largest city) and nearly equal to the aggregated seismic hazard factor in Wellington (New Zealand‘s capital city with the highest seismic hazard in the country among major urban centres) (NZS 2004). Short-period (SDS at a period of 0.2 sec) and long-period (SD1 at a period of 1.0 sec) spectral accelerations for the design basis earthquake (DBE) and relative levels of seismicity for the Hastings building site assuming shallow subsoils (site subsoil class C) are as follows:
SDS = 1.14 g; and
SD1 = 0.46 g.
These design spectral accelerations result in Hastings being considered a region of high seismicity relative to an international scale (ASCE 2014). Design loadings standards in New Zealand (NZS 2002) prescribe that buildings subjected to DBE actions be designed for ―avoidance of collapse of the structural system… or parts of the structure… representing a 279
Appendix E. Displacement-based RC column assessment for a case study interwar building
hazard to human life inside and outside the structure… [and] avoidance of damage to nonstructural systems necessary for… evacuation.‖ In accordance with the seismic assessment guidelines published by the New Zealand Society for Earthquake Engineering (NZSEE 2006), the emphasised performance level considered in the case study assessment discussed herein is the ultimate limit state (ULS), which is theoretically equivalent to the life safety (LS) performance level considered by ASCE (2014). The GNS geological maps (Lee et al. 2011) classify the IMS Hastings building site as resting on beach deposits which consist of sand, gravel, silt and mud on modern coastal plains and lake margins. However, shallow core samples (< 700 mm) taken from below the basement slab were determined to indicate better soil conditions than the classification prescribed in the geological maps. Site subsoil class C (shallow subsoils) was assumed in the seismic assessment based on these qualitative observations, but the analysis was composed to accommodate site subsoil class D (deep subsoils) as well should future geotechnical investigations determine that such subsoil conditions exist.
E.4. Assessment assumptions and general observations The DBE assumed for the case study assessment of the IMS Hastings building has an average return period of 500 years, which is appropriate for a normal building of importance level 2 (NZS 2002). The building was assessed for a future 50-year working life. The summary of design loads and general seismic factors are presented in Table E.1. Table E.1. Design (assessment) loads for the IMS Hastings building Type of load Load magnitude Permanent dead loads Corrugated metal roofing & purlins 0.15 kPa RC self-weight 24 kN/m3 URM self-weight 17 kN/m3 Superimposed dead loads Suspended ceiling 0.15 kPa Services and lighting 0.2 kPa Live loads Floor loading (office & retail) 3.0 kPa, 2.7 kN Corridors and stairway 4.0 kPa, 4.5 kN Roof (accessible) 1.5 KPa, 1.8 kN
Hastings District Council holds drawings for the building that are mostly architectural and consist of plans of interior fit-out and veranda extensions constructed in the 1970s. Structural drawings of the original building construction were not available from the council nor from the building owner. Instead, invasive investigations were coupled with non-invasive ferro 280
Appendix E. Displacement-based RC column assessment for a case study interwar building
scanning to determine the original construction details of the support columns and floor slabs (see Appendix F). It was observed that the building was in excellent condition for its age. At the time of inspection, there were no visible signs to suggest deterioration of the concrete or the reinforcing steel. The frame-wall connection mechanism was identified by invasive investigation at one of the URM infill walls in the first storey where twisted wire loops were observed between the concrete members and the mortar joints of the URM [see Figure E.2(a)]. The URM infill walls along the building perimeter in the first and second storeys were measured to be at least three wythes thick. The URM infill walls along the west perimeter of the building were found to feature cavity construction (i.e., URM wythes separated by air gaps) bounded by RC spandrels on the top and bottom. At the first storey column where invasive investigation was carried out to expose the reinforcing steel, it was found that the anchored slab haunch area was detailed with multiple layers of steel reinforcement and diagonal ties anchored into the octagonal column. Additional steel reinforcement detailing was identified without the aid of original structural construction plans through the removal of concrete cover as exhibited by the photographs in Figure E.2. The foundation of the IMS Hastings building was understood to consist of RC grade beams extending between spread footings beneath the RC columns and topped with a 200+ mm thick RC slab. The foundation arrangement was assumed based on a review of other buildings designed by the same architect and 700 mm deep concrete cores that were drilled into the basement slab. These traits are consistent with the observations of Brodie and Harris (1933) for contemporary RC building foundations in Hawke‘s Bay. The RC basement perimeter walls of the IMS Hastings building are fully buried and were estimated to be at least 280 mm thick. The octagonal columns gradually reduce in cross-sectional area from the basement to the second storey. From invasive investigation, it was determined that the columns were reinforced with eight main longitudinal bars and spiral reinforcing steel. The columns taper outward within each storey at approximately 80% of the column height above the floor slab. From invasive investigation, it was found that the reinforcement generally follows the shape of the taper into the floor slab haunch area.
281
Appendix E. Displacement-based RC column assessment for a case study interwar building
(a) Twisted metal ties embedded between the concrete and the URM infill
(b) Multilayered reinforcement exposed an area of broken slab haunch (ground storey)
(c) Multilayered reinforcement in the first storey slab haunch and in the base of the column
(d) Parapet profile along the building perimeter with parapet partially deconstructed for inspection
Figure E.2. General observations made during the invasive investigation
The depth of the slab haunch at each column is approximately 275 mm and the slab haunch is reinforced with at least two layers of reinforcing steel and a number of diagonal reinforcing bars from the column. The floor slab was investigated on-site using a rebar scope and was estimated to be reinforced with two layers of two-way spanning reinforcing steel. The thickness of the slab was measured as 175 mm at one exposed location in the first storey, and this dimension was confirmed by core sampling in other locations. The spandrel beams were observed to be reinforced with larger diameter horizontal reinforcing steel bars at the top and bottom and smaller diameter vertical reinforcing bars. RC core walls were determined to be detailed with a single layer of steel reinforcement. Several other internal walls in the building were found to have been constructed of URM with reddish clay bricks and strong cement-based mortar. Generally, both internal and external infill URM was found to be in excellent condition and protected from weathering with a layer of rendering plaster (in the case of the external surfaces). Additional findings and specific
282
Appendix E. Displacement-based RC column assessment for a case study interwar building
reinforcement details from the forensic investigation of the IMS Hastings building are illustrated in Appendix F.
E.5. Measured material properties Concrete core and steel reinforcement samples were extracted from multiple locations and tested in a laboratory. The results of the steel reinforcement testing are summarised in Table E.2 and the results of compression tests on 95 mm diameter concrete core samples are summarised in Table E.3. Table E.2. Summary of test results of the steel reinforcement samples Characteristic Yield stress, fy (MPa) Ultimate stress (MPa) Strain at ultimate stress (mm/mm)
# tests 11 13 11
Mean 270 399 0.1309
Stan. dev. 41 50 0.0677
Table E.3. Summary of test results of the concrete core samples Characteristic Max compressive stress, f'co (MPa) Elastic compression modulus, Ec (GPa)
# tests 5 5
Mean 30.28 26.53
Stan. dev. 11.19 5.36
E.6. Structural footprint ratio Information pertaining to the ratio of the sum of RC column and wall cross-sectional areas on the ground floor to the total building footprint area, or structural footprint ratio, was determined by Walsh et al. (2014) for a sample of Hawke‘s Bay Art Deco buildings. Of the 1083 m2 footprint of the IMS Hastings building, approximately 0.6% of the footprint was comprised of RC columns (excluding the infill masonry area), which was well below the average structural footprint ratio of 1.5% for the Walsh et al. (2014) sample group. Structural footprint ratios of 0.6 and 0.9% were recommended as minimums by Glogau (1980) for twostorey and three-storey buildings, respectively, based on a study of the seismic performance of low-rise RC buildings of limited ductility in Japan. However, in a study specific to lowrise RC building performance in the 1931 Hawke‘s Bay earthquake, van de Vorstenbosch et al. (2002) determined that open moment resisting frame systems with structural footprint ratios of approximately 0.4% or greater performed well, and infilled moment resisting frames performed well with structural footprint ratios as low as 0.3%, excluding the infill masonry area. Hence, the practicing engineer could anticipate that a relatively high structural footprint ratio would limit ULS drift demands imposed on the columns by the DBE. 283
Appendix E. Displacement-based RC column assessment for a case study interwar building
E.7. Estimating column displacement demands by nonlinear time-history analysis The nonlinear time-history analysis (NLTHA) used to estimate the displacement demands on the columns of the case study building was comprised of a three-dimensional nonlinear computer model of the building created in a finite/frame element software program (SAP2000TM in this case, although other software programs are also suitable) subjected to a suite of earthquake actions prescribed for the North Island of New Zealand (Oyarzo-Vera et al. 2012). Simulated behaviour amongst all of the structural and pseudo-structural elements of the building was monitored. The spandrel was modelled as a nonlinear shell element with different reinforcement detailing in the longitudinal and vertical directions. The slab haunches and floor slabs were represented in the model as nonlinear shell elements with two layers of two-way spanning reinforcing mesh. It is generally recommended that infill walls be modelled as equivalent struts in accordance with NZSEE (2006) and ASCE (2014) criteria. For performing a NLTHA, NZS (2004) prescribes that a minimum of three relevant earthquake records be applied to the building model and the worst-case scenario be assumed to govern the demands. Three ground-motion records were chosen from the list of historical records deemed appropriate for Hawke‘s Bay by Oyarzo-Vera et al. (2012) whose suggested records were differentiated for different soil types. In order to ensure that the analysis could be easily modified if a lower soil quality were determined based on future soil borings (i.e., change from site subclass C to D), records were chosen for this model that were common to both site subsoil class records suites: El Centro 1940, Tabas 1978, and Hokkaido 2003. As per NZS (2004), scaling of the ground acceleration records was required such that the spectral accelerations of the family of records closely matched the target demand spectrum within the range of interest of 0.4T1 to 1.3T1 , where T1 represents the first mode (fundamental) period for the IMS Hastings building of 0.37 sec as estimated from an elastic spectral response analysis performed previous to the NLTHA. The effect of scaling the spectral responses for the three records chosen is represented graphically in Figure E.3.
284
Appendix E. Displacement-based RC column assessment for a case study interwar building
Figure E.3. Earthquake records scaled to the ULS DBE target spectrum for Hastings site subsoil class C
The time-history scaling factors (k1 x k2) associated with the El Centro, Tabas, and Hokkaido records, respectively, were determined to be 1.50, 0.49, and 1.60 for the ULS DBE (i.e., 100%NBS) demands assuming a structural displacement ductility factor, μ , of 1.25, which is conservatively low for most Hawke‘s Bay Art Deco buildings (Walsh et al. 2014). The raw horizontal accelerations were scaled by these factors and input into the building model as time-history functions. Each earthquake record was considered in two separate load cases so that the H1 and H2 directional accelerations were applied in both orthogonal directions of the building. The selected pairs of ground motion acceleration records were applied as the input for nonlinear direct integration time-history analyses (per NZS 2004), as opposed to the accelerations being applied to a modal time-history analysis, although the latter is less computationally intensive. Geometric nonlinearity parameters were set to P-Delta. Cracked stiffness of concrete cross-sections was assumed as 0.4EcAg for the perimeter walls, and measured material properties obtained from testing were utilised in the NLTHA models whenever possible with the intention of estimating displacement demands as accurately as possible. When subjected to lateral loads, the displaced profile of the building model indicated a torsional response with the peak displacement occurring at opposing diagonal corners of the building. An exaggerated image of the building‘s displacement at the peak acceleration when subjected to the scaled Tabas earthquake at 100%NBS ground accelerations is shown in Figure E.4. The torsional response of the building was mostly attributed to the continuous shop openings along the street frontage.
285
Appendix E. Displacement-based RC column assessment for a case study interwar building
b) Exaggerated displaced shape with Tabas record peak ground acceleration applied
a) 3D model with frame and shell elements
Figure E.4. Modelled response of the IMS Hastings building
Based explicitly on strength and lateral displacement capacity, the critical columns of the building were determined to be the ground storey columns in the main retail area at the street corner where the frame lacks additional support from the URM infill at the perimeter. As expected based on the building‘s configuration, the results of the computer-aided analysis indicated that the ground storey columns in the northwest portion of the building (see Figure E.5) were less critical in comparison to other ground storey columns due to the additional lateral capacity from the perimeter walls and lift cores. The in-plane stresses in the floor slab and slab haunch areas also appeared to be within the capacity of these RC elements as determined from simple hand calculations (NZS 2006). The results of the NLTHA strength assessment indicated that some columns of the IMS Hastings building were likely to be over-stressed by the DBE. However such strength exceedances do not necessarily indicate occupant life safety-threatening failures at the ULS. If the columns do not drift significantly, then axial failure of the columns and partial or total collapse of RC frames within the building may still be averted, especially considering how redundant the frames of most Hawke‘s Bay Art Deco buildings, including the IMS Hastings building, appear to be. Assuming that the slab and slab haunches remain elastic based on the results of the strength-to-demand ratios computed from the model, hinges were predicted to occur at the top and bottom of the columns in accordance with the hinge properties recommended by FEMA (2000) and ASCE (2014). Figure E.5 includes a floor plan of the building at which inter-storey drifts were tracked in each of the time-history scenarios for the column locations labelled A–E. A summary of the maximum inter-storey drifts from the three time-history cases considered is included in Table E.4. The torsional response of the building
286
Appendix E. Displacement-based RC column assessment for a case study interwar building
is clearly identifiable when comparing the storey drift values at column location A relative to the other tracked column locations within the building.
Figure E.5. Ground storey plan showing column positions
Table E.4. Summary of inter-storey drifts by earthquake ground motion record and column location Column El Centro location Ground 1st storey storey A 1.00% 1.31% B 0.74% 1.08% C 0.18% 0.40% D 0.27% 0.59% E 0.51% 0.84%
2nd storey 1.24% 1.16% 0.53% 0.78% 1.04%
Ground storey 0.99% 0.69% 0.21% 0.27% 0.52%
Hokkaido 1st storey 1.33% 1.04% 0.47% 0.60% 0.87%
2nd storey 1.30% 1.14% 0.59% 0.78% 1.07%
Ground storey 0.94% 0.61% 0.29% 0.26% 0.49%
Tabas 1st storey 1.22% 0.93% 0.63% 0.61% 0.83%
2nd storey 1.16% 1.00% 0.78% 0.81% 0.99%
E.8. Estimating column displacement capacities by nonlinear pushover analysis The load and displacement capacity provided by the geometry and the steel reinforcement detailing in the ground floor columns of interwar RC buildings is an especially critical consideration for the assessment of collapse prevention and expected damage concentration (Brodie and Harris 1933; Dowrick 1998). For purposes of developing the worked example, the assessment of column E on the ground storey (see Figure E.5, Table E.4, and Appendix F) to determine its displacement capacity was recorded in detail as reported herein. E.8.1. Assumed material properties
In lieu of material test results, NZSEE (2006, sect. 7.1.1) and TNZ (2004, chap. 6) can be consulted for assumed material properties for analysis. For the column in this worked example, however, several material test results were measured directly (see the mean values listed in Table E.2 and Table E.3). Longitudinal (notated as ―long‖ herein) and transverse 287
Appendix E. Displacement-based RC column assessment for a case study interwar building
(notated as ―trans‖ herein) steel reinforcement material properties were assumed to be equivalent. The elastic modulus of the steel reinforcement, Es , was assumed to be equal to 200,000 MPa, with the yield strain, εy , being determined as the ratio of the mean yield stress, fy , listed in Table E.2, and the elastic modulus, Es , resulting in εy = 0.00135. The concrete unconfined ultimate compressive strength, f'co , was assumed to be equal to the measured mean value of 30.3 MPa as listed in Table E.3. Concrete elastic compression modulus, Ec , was assumed to equal the measured mean of 26.5 GPa as listed in Table E.3. Note that this value is nearly equivalent to the value estimated by following the recommendations of NZS (2006, sect. 5.2.3) that ―for normal density concrete, Ec may be considered as (3320√f'co + 6900) MPa.‖ In accordance with the recommendation of NZS (2006, sect. C6.9.1), the material shear modulus for concrete was estimated as G = 0.4 Ec = 10.6 GPa. E.8.2. Column geometry, reinforcement detailing, and axial loads
Invasive investigations were coupled with non-invasive ferro scanning in order to determine the column reinforcement details (see Appendix F). The geometry and reinforcement detailing of the ground floor columns of the IMS Hastings building were determined to be as follows:
Octagonal column geometry with each of the eight sides being 185 mm long, effectively equivalent to a column with circular cross-sectional diameter D = 447 mm and gross cross-sectional area of Ag = 0.157 m2;
Spiral transverse reinforcement bar of diameter dtrans = 6.4 mm vertically spaced centre-to-centre at s = 90 mm pitch;
Eight longitudinal reinforcement bars of diameter dlong = 28.6 mm with 1070 mm lap splice spaced approximately equivalently around the inside of the spiral transverse reinforcement (i.e., one longitudinal bar located every 45 degrees around the circular cross-section); and
75 mm average concrete clear cover from the outside edge of the column to the outside edge of the spiral transverse reinforcement bar.
288
Appendix E. Displacement-based RC column assessment for a case study interwar building
The ground storey column clear-height to be deformed in double curvature with assumed flexurally rigid end restraints, L , was measured as 3930 mm (see Appendix F). If the direction of lateral loading being considered on a given column is in-plane with partial-height masonry infill (as is common on the exterior of Hawke‘s Bay Art Deco buildings per Walsh et al. 2014), then the column height in this direction of loading should be assumed to be the clear-storey height minus the infill wall height. Such a scenario may represent a ―short column‖ vulnerability (NZSEE 2014), and the column failure mechanism is more likely to be shear-controlled in this direction of loading. In the case of the considered column E (see Figure E.5), however, no mid-height restraint such as masonry infill was present. For the case study ground floor column E (see Figure E.5), the concentrated axial load, N , was determined from the analytical results of the computer-aided model. All self-weight and imposed gravity loads (see Table E.1) above the column resulted in a total axial compression load of 990 kN. The minimum and maximum total axial compression load conditions from any of the earthquake loading scenarios were 945 kN and 1053 kN, respectively. Note that the bandwidth of axial load extremes was determined to be relatively small for the considered interior column (only approximately +/- 5% from the gravity axial load of 990 kN). Exterior columns are likely to experience relatively larger bandwidths of axial loads effectuated by frame action during earthquake loading than are interior columns, and these axial loads can be estimated from the results of the computer-aided NLTHA. In this case, the engineer should consider that the minimum shear strength of the column will occur when the column is under the minimum axial compression load, and the drift ratio at axial load failure may be governed by the maximum axial compression load. E.8.3. Idealised backbone pushover model
An idealised backbone model defining the key damage states of an existing reinforced concrete column under lateral loading (i.e., flexural yielding, shear failure, and axial load failure) was developed by Elwood and Moehle (2006). The nominal moment capacity of the column cross-section, Mn , was determined to be equal to 277 kN-m for the case study column assuming that the entire cross-section of the column was intact (i.e., no spalling of the cover concrete), the minimum axial load of 945 kN was applied, and the strength of the steel reinforcement was equal to the measured mean yield stress, fy , of 270 MPa as listed in Table E.2 . In this instance, the plastic moment capacity was determined by transforming the column into an equivalent rectangular column using the empirical method proposed by 289
Appendix E. Displacement-based RC column assessment for a case study interwar building
Whitney (1942), with the result confirmed by using the sectional analysis program Response2000TM (Bentz 2000). Accounting for overstrength caused by strain hardening in the steel reinforcement by assuming that the strength of the steel reinforcement was equal to the measured mean ultimate stress of 399 MPa as listed in Table E.2, the probable moment capacity of the column cross-section, Mp , was determined to be equal to 342 kN-m for the case study column, representing an overstrength ratio of approximately 1.23. By comparison, NZSEE (2006, sect. 7.1.1) notes that this ratio should be 1.16. [Note that the designations "nominal strength" and "probable strength" are used differently in NZSEE (2006) than they are in this reported case study]. According to Elwood and Moehle (2006), the idealised ―backbone approximates the gradual yielding of the column with an elastic-perfectly plastic response. Yielding is assumed to occur once the shear demand reaches the plastic shear capacity, Vp . For the assumed boundary conditions... the column plastic shear capacity can be determined as follows‖: Eq. (E.1)
In regard to estimating the curvature ductility capacity of the plastic hinges assumed to form at the top and bottom of the case study column, NZSEE (2006, sect. 7.2.4) notes that ―Priestley and Kowalsky (2000) have shown that the first yield curvature is given with very good accuracy as follows… for circular columns‖: Eq. (E.2)
Other equations are recommended by Priestley and Kowalsky (2000) for rectangular columns and beams. Note that first yield curvature can be more accurately determined by considering a cracked, transformed cross-section at initial yield of the longitudinal tension reinforcement. Assuming the column is in double curvature, fixed against rotation at both ends, and experiences a linear variation in curvature over its height, the drift ratio at yield due to flexure can be estimated as follows: Eq. (E.3)
The Elwood and Moehle (2006) backbone model was developed based on experimental test data comprised of RC columns with deformed reinforcement bars. However, all reinforcement in the Art Deco columns considered by Walsh et al. (2014) was identified as being comprised of smooth, round bars. Various other studies into RC columns with similar detailing have found that round longitudinal bars with ineffective anchorage or development 290
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length can induce failure at relatively low loads (Fabbrocino et al. 2005), but that properly spliced or anchored round longitudinal bars are likely to effectuate higher column deformability than deformed bars (Ricci et al. 2013) and induce rocking mechanisms at the base of the columns (Arani et al. 2013). The practicing engineer should consider closely the anchorage and lap splice conditions in the column being assessed and compare the anticipated tensile forces in the longitudinal reinforcing steel corresponding to plastic flexural capacity hinge formation to the experimental results reported by Fabbrocino et al. (2005). The pushover capacity of an RC column in which longitudinal reinforcement pull-out is expected to occur prior to plastic hinge formation may be estimated by considering only the contribution to lateral resistance from rocking mechanisms as proposed by Arani et al. (2014). Where able to be identified on plans, longitudinal reinforcement bars in the Art Deco columns considered by Walsh et al. (2014) were either continuous through the beam-column joints or anchored using 180-degree hooks with similar geometry and detailing to experimentally tested RC columns that did not experience pull-out as reported by Ricci et al. (2013). Hence, for purposes of estimating Art Deco column capacities, Walsh et al. (2014) assumed that lap splice and anchorage pull-out did not govern the drift capacity of any of the columns considered. For the reported case study column and in accordance with the recommendation of Arani et al. (2014) for RC columns with smooth, round longitudinal reinforcement bars, a bond stress, u , equal to 0.3√ f'co (MPa units) was assumed, equalling 1.65 MPa. According to Elwood and Moehle (2006), ―the stress in the tension reinforcement at the point of effective yield can be taken equal to the yield stress for columns with axial load below [N/(Ag∙f'co)] = 0.2 and equal to zero for axial loads above [N/(Ag∙f'co)] = 0.5, with a linear interpolation between these points (Elwood and Eberhard 2006).‖ For the case study column, N/(Ag∙f'co) = 0.20, and the corresponding stress in the longitudinal tension reinforcement at the point of effective yield was determined as fs = 270 MPa. According to Elwood and Moehle (2006), ―Elwood and Eberhard (2006) have shown that the drift ratio at yield due to bar slip depends on the column axial load and can be estimated as follows‖: Eq. (E.4)
291
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According to Elwood and Moehle (2006), ―assuming the column is fixed against rotation at both ends, the drift ratio at yield due to shear deformations can be estimated by idealizing the column as consisting of a homogeneous material with a shear modulus G.‖ In accordance with Elwood and Moehle (2006), the drift ratio at yield due to shear deformations was determined as follows: Eq. (E.5)
. /
According to Elwood and Moehle (2006), ―the effective yield drift ratio can be considered as the sum of the drifts due to flexure, bar slip, and shear‖ at yield, resulting in δy = 0.0089 for the case study column. According to Elwood and Moehle (2006), ―the shear stress, v , can be estimated based on the plastic shear capacity‖ divided by the effective shear area of the cross-section. In the case of a circular cross-section, the effective shear area was assumed to be equal to 0.7Ag (Merta and Kolbitsch 2006). Hence, the stress was determined as follows: Eq. (E.6)
Concrete core dimensions were assumed to be represented by the concrete area bounded by the outside edges of the transverse reinforcement, consistent with the assumptions of Mander et al. (1988) and NZS (2006, sect. 10.1). Hence, for the case study column, the confined core diameter was determined to be dcore = 297 mm. The cross-sectional area of the transverse reinforcing bar was As_trans = 32 mm2 . The volumetric transverse reinforcement ratio considering the circular cross-section and spiral reinforcement was determined to be ρs = 0.0048 (per Mander et al. 1988). However, the empirical equations proposed by Elwood and Moehle (2006) for predicting the column drift ratio at shear failure, δs , and the column drift ratio at axial failure, δa , were developed for rectangular columns. Hence, for purposes of estimating the equivalent rectangular geometry, the column was transformed into an equivalent rectangular column using the empirical method proposed by Whitney (1942). The equivalent column cross-sectional dimension orthogonal to the considered lateral load was assumed to be b = 438.8 mm, and the equivalent column cross-sectional dimension parallel to the considered lateral load was assumed to be h = 357.6 mm. All longitudinal reinforcement was assumed equally distributed in one of two layers relative to the direction of transverse load considered, with the two layers separated by a distance equal to 2/3 of the core dimension in the actual octagonal (circular) cross-section. In the case of the worked example, 292
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this value would be approximately dcore,rect = 200 mm. The width of the confined core in the equivalent rectangular section was assumed to be equal to the equivalent width minus the clear cover on each side, resulting in a value of approximately bcore,rect = 290 mm For purposes of the worked example, the spiral transverse reinforcement was treated as equivalent discrete rectangular hoops vertically spaced centre-to-centre at s = 90 mm. The resulting transverse reinforcement parallel to the direction of lateral loading considered for the equivalent rectangular section was determined to be ρs,rect = 0.0025 (per Mander et al. 1988). In accordance with Elwood and Moehle (2005a, 2006), the drift ratio at shear failure was determined as follows: Eq. (E.7) √
In accordance with Elwood and Moehle (2005b, 2006), the drift ratio at axial failure was determined as follows: ( (
)
(
))
(
(
)
)
Eq. (E.8)
E.8.4. Shear strength reduction due to plastic hinging
The Elwood and Moehle (2006) backbone model is premised on shear failure occurring prior to axial failure. According to Elwood and Moehle (2006), ―experimental studies have shown that axial load failure tends to occur when the shear strength degrades to approximately zero (Yoshimura and Yamanaka 2000). Hence, the final point on the idealised backbone assumes a shear strength of zero.‖ Therefore, in the case that the predicted column drift ratio at shear failure, δs , is larger than the predicted column drift ratio at axial failure, δa , (as is the case in the worked example) then the column‘s potential drift capacity is expected to be governed by the predicted column drift ratio at shear failure, δs (i.e., the larger value controls). However, according to Elwood and Moehle (2006), ―before the idealised backbone model can be used to assess the capacity of an existing reinforced concrete column, it must be determined whether the column is expected to experience shear failure after yielding of the longitudinal reinforcement, a common characteristic of all the column tests used to develop the drift capacity models described above. To determine whether a column is likely to experience shear failure after flexural yielding, the plastic shear capacity, Vp , should be compared with an appropriate shear strength model, such as that proposed by Sezen and Moehle (2004).‖ 293
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Hence, if shear failure were to occur in a column prior to flexural yielding, then the column drift ratio at shear failure, δs , predicted by application of the Elwood and Moehle (2006) model would likely be overestimated. The shear capacity provided by the transverse reinforcement was determined using the equation recommended by Priestley et al. (1994) for a circular cross-section as follows: (
)
Eq. (E.9)
The ―shear span‖ of the column is the distance from the section of the column sustaining the maximum applied bending moment under lateral loading to the point of contraflexure (i.e., section of the column with no applied bending moment). In a column deformed in double curvature with assumed flexurally rigid end restraints, the shear span distance, z , is effectively half of the column clear-height (e.g., 1965 mm in the case of the worked example). As with Elwood and Moehle (2006), the empirical equation proposed by Sezen and Moehle (2004) for predicting the column shear strength provided by the concrete was developed for rectangular columns. The distance from the extreme compression fibre to the centroid of the longitudinal tension reinforcement, d , for the equivalent rectangular section based on the empirical Whitney (1942) model was determined to be 262 mm. In accordance with Sezen and Moehle (2004), the shear capacity provided by the concrete in the equivalent rectangular section was determined as follows: (
√
√
√
)
Eq. (E.10)
In accordance with Sezen and Moehle (2004), the nominal shear strength of the column corresponding to a displacement ductility demand of 2.0 or less was determined as follows: Eq. (E.11)
To account for shear strength degradation at higher displacement ductility demands, a reduction factor, k , needs to be determined. According to Sezen and Moehle (2004), ―the factor k is defined to be equal to 1.0 for displacement ductility less than 2, to be equal to 0.7 for displacement ductility exceeding 6, and to vary linearly for intermediate displacement ductilities.‖ In the case of the worked example, the maximum potential displacement ductility demand effectuated by plastic hinge development was determined to be µdispl,col = 3.1 by applying the predictive method of Elwood and Moehle (2006). Hence, the strength reduction 294
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factor for use in the shear capacity predictive model of Sezen and Moehle (2004) was k = 0.92, and the predicted shear strength of the column corresponding to the ultimate displacement ductility demand was determined to be kVn = 147 kN. In interpreting the results of this worked example and exercises based off of it, Elwood and Moehle (2006) advise that ―...the plastic shear capacity should fall in the range between the initial shear strength, Vn , and the final shear strength, 0.7Vn . Because there is some dispersion between actual and calculated shear strength, some columns with shear demand less than the calculated shear, or plastic shear capacity greater than Vn , may still experience shear failure after flexural yielding. Currently, engineering judgment is required to select which columns with Vp outside the Vn to 0.7Vn range are still expected to experience shear failure after flexural yielding, and hence can be evaluated using the proposed idealised backbone model.‖ In the worked example in which the minimum axial load was considered, the column shear ratio at a displacement ductility demand of 2.0 or less, Vp / Vn , was determined to be 1.09 and the column shear ratio at the ultimate displacement ductility demand, Vp / kVn , was determined to be 1.18. (These ratios were altered negligibly when the maximum axial load was considered and so are not reported here.) Note that these values of Vp / Vn exceed the range recommended for assessment using the Elwood and Moehle (2006) pushover model. Hence, the case study column could theoretically experience shear failure just prior to flexural yielding (i.e., be governed by shear failure criteria per ASCE 2014) and may not actually reach the considered ultimate displacement ductility demand level of 3.1 corresponding to flexure-shear failure criteria. However, the behaviour of RC columns with Vp / Vn ratios just above 1.0 is uncertain and the assumption of shear failure criteria for such columns is likely overly conservative (Li et al. 2014). Furthermore, the exceedance of a column‘s shear capacity does not necessarily result in the immediate loss of axial loadcarrying capacity as determined in displacement-based studies (e.g., Elwood and Moehle 2006). Nonetheless, even with the most conservative assumption being made, the column drift capacity of the case study column is at least equal to approximately 0.8% where the flexural pushover curve and shear strength envelope first intersect (see Figure E.6). Another potentially limiting factor to column drift capacity is the effect of bidirectional loading on columns with limited ductility (Boys et al. 2008). Practicing engineers should use judgment in interpreting the results of assessment methods based on unidirectional behaviour, especially when performing a nonlinear time-history analysis using ground motion records and considering building spectral responses with relatively strong motions in two orthogonal 295
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directions. Ang et al. (1989) and Wong et al. (1993) developed a relationship between flexure and shear interaction based on experimental results of circular columns to account for the effects of bidirectional loading, and it was generalised so as to be related to alternative models for unidirectional loading by Priestley et al. (1994) as shown in Figure E.6. Following consideration of the various models presented, it was decided to adopt a conservative drift capacity of 0.8% as the threshold for shear failure for purposes of this case study analysis. As will be shown in Section E.8.6, this conservatively assumed drift capacity of 0.8% still results in the determination of a high %NBS.
0.00
0.01
Drift 0.03
0.02
Lateral load (kN)
200
0.04
0.05
0.06
Predicted point of shear failure (Elwood and Moehle 2006)
150
100 Predicted point of shear failure (Sezen and Moehle 2004)
50
Predicted point of axial failure (Elwood and Moehle 2006)
0 0
1
2
3 4 Displacement ductility
5
6
7
Shear force at flexural strength (Elwood and Moehle 2006) Unidirectional shear strength envelope (Sezen and Moehle 2004) Bidirectional shear strength envelope (Ang et al. 1989; Wong et al. 1993)
Figure E.6. Shear strength capacity of the case study column as affected by flexure and shear interaction (minimum axial load scenario)
E.8.5. Flexural strength reduction due to longitudinal bar buckling
For an alternative column expected to undergo flexural yielding prior to shear failure, the effect of longitudinal bar buckling on the flexural strength of the column should also be considered. An empirical model that can be used to predict column drift at the onset of longitudinal bar buckling was proposed by Berry and Eberhard (2005). This model requires the consideration of two factors not yet defined in the worked example. The first factor determined was the effective confinement ratio, which was defined as follows: Eq. (E.12)
The second factor is the transverse reinforcement coefficient, ke,bb , for which Berry and Eberhard (2005) recommend that ―ke,bb = 40 for rectangular-reinforced columns and 150 for spiral-reinforced columns… Because little data were available for large values of [s /dlong] , ke,bb should be taken as 0.0 for columns in which [s /dlong] exceeds 6.‖ The s / dlong ratio for 296
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the case study column was computed to be 3.1. Hence, the transverse reinforcement coefficient was assumed to be ke_bb = 150. In accordance with Berry and Eberhard (2005), the estimated drift corresponding to the onset of longitudinal bar bucking was determined as follows: .
/(
).
/
Eq. (E.13)
Note that, for the case study column, the predicted drift at longitudinal bar buckling far exceeded the predicted drift at any other limit state (see Figure E.6). Hence, bar buckling was not expected to control the lateral behaviour of the case study column from the IMS Hastings building. E.8.6. Column %NBS by displacement-based assessment
The estimated %NBS for the case study column was determined by dividing the estimated column drift capacity (assumed as 0.8%, see Figure E.6) by the maximum ULS column drift demand for column E on the ground storey (0.52%, see Figure E.5 and Table E.4), resulting in a %NBS higher than 100. Note that the drift capacity in the worked example was determined for the interior ground storey column E whereas the maximum ULS drift demand for all columns was associated with the exterior first storey column A (see Figure E.5 and Table E.4). Hence, the pushover backbone model analysis would need to be repeated for different column locations on other storeys. As noted previously, exterior columns are likely to experience relatively larger bandwidths of axial loads effectuated by frame action during earthquake loading than are interior columns. Two scenarios of flexure and shear interaction pertaining to minimum and maximum axial load scenarios, respectively, should be considered for such columns (see Figure E.6). The ULS column drift demands determined from the computer-aided NLTHA (see Table E.4) were based on ground-motion time-history records scaled to the ULS DBE spectrum (i.e., 100%NBS demands, see Figure E.3). In order to precisely determine the %NBS for the columns, however, the time-history records applied in the NLTHA model should actually be scaled to an increased target demand spectrum (for potential %NBS scores above 100%NBS) or a reduced target demand spectrum (for potential %NBS scores below 100%NBS) until the maximum drift demands determined from the NLTHA are equivalent to the estimated drift capacities, at which point the %NBS would be equivalent to the proportion of the scaled target spectrum to the ULS DBE spectrum (see Figure E.3). 297
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In the case study assessment presented herein, a ―column sway‖ collapse mechanism (NZSEE 2006) was assumed to occur, which generally results in conservatively high predicted nonlinear column displacement demands. Also in the case study assessment presented herein, plastic hinges in the RC columns were assigned to follow generic FEMA (2000) and ASCE (2014) criteria, which are included in newer versions of SAP2000TM by default. Alternatively, the plastic hinges could also be assigned to behave exactly as determined by the backbone pushover model proposed by Elwood and Moehle (2006) while accounting for the effects of assumed changing axial loads on the columns at each storey. However, if the nonlinear behaviours of axial and shear capacities are not considered in the computational model, then manual calculations to determine whether shear and axial failure mechanisms control the collapse of the considered columns are still required following the computer-aided NLTHA. Finally, in regard to capacity reduction factors for assessing RC elements, NZSEE (2006) notes that ―the strength reduction factor ø for flexure should be taken as 1.0. A strength reduction factor ø for shear of 0.85 should be built into the shear strength.‖ Hence, at the discretion of the engineer depending on how conservative their assumptions for material strengths were, and with the expectation of shear-controlled failure mechanisms in some considered RC columns, a reduction in shear strength of 15% may be warranted. E.8.7. Effects of URM infill walls on column behaviour
Of the 150 contemporary non-residential buildings identified in Hastings, at least 40% were identified as having clay brick URM infill panels (Walsh et al. 2014), including the IMS Hastings building [see Figure E.1(a)–(b)]. In many Hawke‘s Bay Art Deco buildings, URM infill panels only rise partial-height within any given perimeter frame, truncated most usually by window frames [see Figure E.1(a)]. As noted previously, if the direction of lateral loading being considered on a given column is in-plane with partial-height masonry infill, then a ―short column‖ vulnerability may exist (NZSEE 2014), and the column failure mechanism is more likely to be shear-controlled in this direction of loading as the effective shear span of the column is reduced. Asymmetrically placed infill panels, typical of buildings which are located on street corners such as the IMS Hastings building, are capable of causing plan irregularities and torsional responses, as simulated in the NLTHA model reported herein. However, Dowrick and Rhoades (2000) observed that low-rise RC-framed buildings with asymmetrically placed wall panels rarely suffered more damage in numerous historic New 298
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Zealand earthquakes than did their counterparts with symmetrically placed infill walls. Furthermore, Dowrick and Rhoades (2000) observed that the presence of infill walls likely benefitted several buildings during earthquakes.
E.9. Summary and recommendations The detailed seismic assessment of the Art Deco case study IMS Hastings building was completed in sequence with the following generic steps:
A computer-aided model with assigned plastic hinges at the tops and bottoms of all columns was subjected to three time-history records in order to determine maximum column displacement demands as well as minimum and maximum column axial loads;
An empirical nonlinear column pushover model (Elwood and Moehle 2006) was then utilised in order to estimate the column displacement capacity under conditions in which the column would be expected to flexurally yield prior to failing in shear;
For the considered column with a high ratio of shear demand at plastic hinging to nominal shear capacity, Vp / Vn , additional column failure criteria were checked against an empirical flexure-shear interaction model (Sezen and Moehle 2004); and
A capacity/demand (%NBS) ratio was able to be determined.
The NLTHA results for the considered case study indicated that the building would be expected to deform torsionally in most time-history cases due largely to eccentrically placed URM infill walls and RC lift shafts. Nonetheless, the structural redundancy of the building and contribution from stiffening components considered in the NLTHA model, including the RC slab and URM infill walls, would be expected to limit the building‘s inter-storey drifts such that the %NBS of the columns would remain relatively high. Recommendations exhibited in this case study for structural engineers performing detailed seismic assessments on similar interwar Art Deco RC frame buildings are as follows:
Owners of regularly configured interwar Art Deco buildings in Hawke‘s Bay may receive higher seismic assessment scores from engineering consultants by commissioning invasive and non-invasive investigations in order to accurately determine material strengths and structural configurations; 299
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Engineers seeking accuracy and the avoidance of excessive conservativeness should focus in their assessments on leveraging the inherent stiffness and redundancy of the complete structure to limit the estimated inter-storey drift demands instead of, as is traditionally done, focusing on increasing the estimated strength capacity of structural elements. Practically, this approach requires that engineers utilise system-oriented assessment techniques such as modal response spectrum analyses or, preferably, displacement-based assessment techniques such as the nonlinear procedures exemplified herein;
Potential vulnerabilities identified among the Art Deco columns that should be closely considered during assessment include splice or anchorage failure of smooth reinforcement bars, premature buckling of longitudinal reinforcement in columns, and column shear strength degradation at high ductility demands; and
Infill walls may have contributed greatly to the successful performance of similar buildings in previous earthquakes and should be included as components in NLTHA models. However, the case study as presented herein directs the engineer on how to account for the potentially detrimental effects caused by infill walls, including the torsional modal reactions caused by eccentrically placed infill walls (by identifying the increased displacement demands on columns located far from the centre of eccentricity in the NLTHA model) and ―short column‖ behaviour caused by partialheight infill (by reducing the column clear-height for pushover capacity modelling).
E.10. Additional considerations The scope of the case study was limited to assessing the behaviour of a single RC column under lateral loading. Note that the most significant hazard to people during an earthquake may not be the failures of load-bearing structural elements such as RC columns, but rather the collapse of non-structural parts and components. Although Hawke‘s Bay‘s Art Deco building stock has few tall chimneys and gable end walls, slender RC parapets and URM infill walls are prominent in Art Deco buildings (Walsh et al. 2014). These components are prone to outof-plane collapse and thus can be especially dangerous to pedestrians just outside a building (Ingham and Griffith 2011; Cooper et al. 2012; Walsh et al. 2015). In addition, other building components and behaviours were not considered in the worked example, including but not
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limited to foundation settlement, foundation overturning, liquefaction, beam shear, slab shear, wall shear, wall overturning, and beam elongation / diaphragm dilation.
E.11. Acknowledgements The authors would like to thank those associated with the Napier Art Deco Trust (http://www.artdeconapier.com) for providing the authors with access to the case study buildings and to building plans considered and referenced by Walsh et al. (2014). As it relates to the specific case study reported herein, the authors are especially grateful to the owners of the IMS Hastings building and to the structural engineering consultants at EQ STRUC, Ltd. (http://www.eqstruc.co.nz) who undertook the building investigation.
E.12. References Ang, B., Priestley, M.J.N., and Paulay, T. (1989). ―Seismic shear strength of circular reinforced concrete columns.‖ ACI Structural Journal, 86(1), 45–49. Arani, K., Marefat, M., Amrollahi-Biucky, A., and Khanmohammadi, M. (2013). ―Experimental seismic evaluation of old concrete columns reinforced by plain bars.‖ The Structural Design of Tall and Special Buildings, 22(3), 267–290, 10.1002/tal.686. Arani, K., Di Ludovico, M., Marefat, M., Prota, A., and Manfredi, G. (2014). ―Lateral response evaluation of old type reinforced concrete columns with smooth bars.‖ ACI Structural Journal, 111(4), 827–838. ASCE (American Society of Civil Engineers). (2014). ―Seismic evaluation and retrofit of existing buildings.‖ ASCE 41-13, Reston, Virginia. Bentz, E. (2000). ―Response-2000 - Reinforced concrete sectional analysis using the modified compression field theory.‖ Version 1.0.5, (15 September 2013). Berry, M., and Eberhard, M. (2005). ―Practical performance model for bar buckling.‖ Journal of Structural Engineering, 131(7), 1060–1070, 10.1061/(ASCE)07339445(2005)131:7(1060). Boys, A., Bull, D., and Pampanin, S. (2008). ―Seismic performance assessment of inadequately detailed reinforced concrete columns.‖ Proceedings of the New Zealand Society for Earthquake Engineering Conference, Wellington, New Zealand. Brodie, A., and Harris, B. (1933). ―Report of the Hawke‘s Bay earthquake (3rd February, 1931), chapter 6: Damage to buildings.‖ NZ Department of Scientific and Industrial Research, Wellington, New Zealand, 108–115.
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Cooper, M., Carter, R., and Fenwick, R. (2012). Canterbury Earthquakes Royal Commission final report, volumes 1–7, Royal Commission of Inquiry, Christchurch, New Zealand, . Dowrick, D. (1998). ―Damage and intensities in the magnitude 7.8 1931 Hawke‘s Bay, New Zealand, earthquake.‖ Bulletin of the New Zealand National Society for Earthquake Engineering, 31(3), 139–163. Dowrick, D. (2006). ―Lessons from the performance of buildings in the Mw 7.8 Hawke‘s Bay earthquake of 1931.‖ Proceedings of the New Zealand Society for Earthquake Engineering Conference, Wellington, New Zealand. Dowrick, D., and Rhoades, D. (2000). ―Earthquake damage and risk experience and modelling in New Zealand.‖ Proceedings of the 12th World Conference on Earthquake Engineering, Wellington, New Zealand. Elwood, K., and Eberhard, M. (2006). ―Effective stiffness of reinforced concrete columns.‖ PEER Research Digest, 2006/01, College of Engineering, University of California, Berkeley. Elwood, K., and Moehle, J. (2005a). ―Drift capacity of reinforced concrete columns with light transverse reinforcement.‖ Earthquake Spectra, 21(1), 71–89, 10.1193/1.1849774. Elwood, K., and Moehle, J. (2005b). ―Axial capacity model for shear-damaged columns.‖ ACI Structural Journal, 102(4), 578–587. Elwood, K., and Moehle, J. (2006). ―Idealized backbone model for existing reinforced concrete columns and comparisons with FEMA 356 criteria.‖ The Structural Design of Tall and Special Buildings, 15(5), 553–569, 10.1002/tal.382. Fabbrocino, G., Verderame, G., and Manfredi, G. (2005). ―Experimental behaviour of anchored smooth rebars in old type reinforced concrete buildings.‖ Engineering Structures, 27(10), 1575–1585, 10.1016/j.engstruct.2005.05.002. FEMA (Federal Emergency Management Agency). (2000). ―Prestandard and commentary for the seismic rehabilitation of buildings.‖ FEMA 356, Washington, D.C. Glogau, O. (1980). ―Low-rise reinforced concrete buildings of limited ductility.‖ Bulletin of the New Zealand National Society for Earthquake Engineering, 13(2), 182–193. Ingham, J., and Griffith, M. (2011). The performance of earthquake strengthened URM buildings in the Christchurch CBD in the 22 February 2011 earthquake. Addendum Report to the Royal Commission of Inquiry, Christchurch, New Zealand, . Lee, J., Bland, K., Townsend, D., and Kamp, P. (2011). ―Geology of the Hawke‘s Bay area.‖ Institute of Geological & Nuclear Science (GNS), Lower Hutt, NZ, 1:250 000 geological map 8, 1 sheet +93 p. 302
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Li, Y., Elwood, K., and Hwang, S. (2014). ―Assessment of ASCE/SEI 41 concrete column provisions using shake table tests.‖ ACI SP-297–2, Farmington Hills, Michigan. Mander, J., Priestley, M.J.N., and Park, R. (1988). ―Theoretical stress-strain model for confined concrete.‖ Journal of Structural Engineering, 114(8), 1804–1826, 10.1061/(ASCE)0733-9445(1988)114:8(1804). Merta, I., and Kolbitsch, A. (2006). ―Shear area of reinforced concrete circular cross-section members.‖ Proceedings of the 31st Conference on Our World in Concrete Structures, Singapore, . Mitchell, A. (1931). ―The effects of earthquakes on buildings and structures.‖ NZIA Journal, 12(10), 111–117. New Zealand Parliament. (2004). Building Act 2004, Department of Building and Housing – Te Tari Kaupapa Whare, Ministry of Economic Development, New Zealand Government, Wellington, New Zealand. New Zealand Parliament. (2005). Building (specified systems, change the use, and earthquake-prone buildings) regulations, Department of Building and Housing, Ministry of Economic Development, New Zealand Parliament, Wellington, New Zealand. NZHPT (New Zealand Historic Places Trust). (2013). ―200 Queen Street West and 124 and 128 Market Street North, HASTINGS,‖ NZHPT, The Register. (15 April 2013). NZS (Standards New Zealand). (2002). ―Structural design actions, Part 0: General principles.‖ NZS 1170.0:2002, Incorporated Amendments 1–5. Australian Standards (AS) and Standards New Zealand (NZS) Joint Technical Committee BD-006, Wellington, New Zealand. NZS (Standards New Zealand). (2004). ―Structural design actions, Part 5: Earthquake actions – New Zealand.‖ NZS 1170.5:2004, Standards New Zealand Technical Committee BD006-04-11, Wellington, New Zealand. NZS (Standards New Zealand). (2006). ―Concrete structures standard, Part 1: The design of concrete structures.‖ NZS 3101:2006, Incorporated Amendment No. 1. Standards New Zealand Concrete Design Committee P 3101, Wellington, New Zealand. NZSEE (New Zealand Society for Earthquake Engineering). (2006). Assessment and improvement of the structural performance of buildings in earthquakes, recommendations of a NZSEE study group on earthquake risk of buildings, Incorporated Corrigenda No. 1 & 2, New Zealand Society for Earthquake Engineering, Wellington, New Zealand. NZSEE (New Zealand Society for Earthquake Engineering). (2014). Assessment and improvement of the structural performance of buildings in earthquakes, recommendations of a NZSEE project technical group, Incorporated Corrigenda No. 3, Section 3, Initial 303
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seismic assessment, New Zealand Society for Earthquake Engineering, Wellington, New Zealand. Oyarzo-Vera, C., McVerry, G., and Ingham, J. (2012). ―Seismic zonation and default suite of ground-motion records for time-history analysis in the North Island of New Zealand.‖ Earthquake Spectra, 28(2), 667–688, 10.1193/1.4000016. Priestley, M.J.N., Verma, R., and Xiao, Y. (1994). ―Seismic shear strength of reinforced concrete columns.‖ Journal of Structural Engineering, 120(8), 2310–2329, 10.1061/(ASCE)0733-9445(1994)120:8(2310). Priestley, M.J.N., and Kowalsky, M. (2000). ―Direct displacement-based seismic design of concrete buildings.‖ Bulletin of the New Zealand Society for Earthquake Engineering, 33(4), 421–444. Ricci, P., Verderame, G., and Manfredi, G. (2013). ―ASCE/SEI 41 provisions on deformation capacity of older-type reinforced concrete columns with plain bars.‖ Journal of Structural Engineering, 10.1061/(ASCE)ST.1943 -541X.0000701, 04013014. Sezen, H., and Moehle, J. (2004). ―Shear strength model for lightly reinforced concrete columns.‖ Journal of Structural Engineering, 130(11), 1692–1703, 10.1061/(ASCE)0733-9445 (2004)130:11(1692). Sozen, M., Monteiro, P., Moehle, J., and Tang, H. (1992). ―Effects of cracking and age on stiffness of reinforced concrete walls resisting in-plane shear.‖ Proceedings, 4th Symposium on Current Issues Related to Nuclear Power Plant Structures, Equipment and Piping, Orlando, Florida. TNZ (Transit New Zealand). (2004). Evaluation of bridges and culverts, chapter 6, NZ Transport Agency, Wellington, New Zealand. van de Vorstenbosch, G., Charleson, A., and Dowrick, D. (2002). ―Reinforced concrete building performance in the Mw 7.8 1931 Hawke‘s Bay, New Zealand, earthquake.‖ Bulletin of the New Zealand Society for Earthquake Engineering, 35(3), 149–164. Walsh, K., Elwood, K., and Ingham, J. (2014). "Seismic considerations for the Art Deco interwar reinforced-concrete buildings of Napier, New Zealand." Natural Hazards Review, 16(4), 04014035. Walsh, K., Dizhur, D., Shafaei, J., Derakhshan, H., and Ingham, J. (2015). ―In situ out-ofplane testing of unreinforced masonry cavity walls in as-built and improved conditions.‖ Structures, 3, 187–199, 10.1016/j.istruc.2015.04.005. Whitney, C. (1942). ―Plastic Theory of reinforced concrete design.‖ Transactions ASCE, 107, 251–326. Wong, Y., Paulay, T., and Priestley, M.J.N. (1993). ―Response of circular reinforced concrete columns to multi-directional seismic attack.‖ ACI Structural Journal, 90(2), 180–191. 304
Appendix E. Displacement-based RC column assessment for a case study interwar building
Yoshimura, M., and Yamanaka, N. (2000). ―Ultimate limit state of RC columns.‖ PEER Report 2000/10, College of Engineering, University of California, Berkeley, 331–326.
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Appendix E. Displacement-based RC column assessment for a case study interwar building
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Appendix F. Illustrated findings from the invasive inspection of the IMS Hastings building
Appendix F. Illustrated findings from the invasive inspection of the IMS Hastings building Additional illustrations and details from the invasive inspection of the IMS Hastings building as
described
in
Appendix
E
are
included
307
in
the
following
appendix.
Appendix F. Illustrated findings from the invasive inspection of the IMS Hastings building
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Appendix F. Illustrated findings from the invasive inspection of the IMS Hastings building
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Appendix F. Illustrated findings from the invasive inspection of the IMS Hastings building
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Appendix F. Illustrated findings from the invasive inspection of the IMS Hastings building
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Appendix F. Illustrated findings from the invasive inspection of the IMS Hastings building
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Appendix G. Additional data and photographs from the testing of RC frames extracted from a building damaged during the Canterbury earthquakes
Appendix G. Additional data and photographs from the testing of RC frames extracted from a building damaged during the Canterbury earthquakes Half cycle-by-cycle damage observations and performance measurements from the testing of the Clarendon Tower frame components are illustrated in the following tables in this appendix.
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Appendix G. Additional data and photographs from the testing of RC frames extracted from a building damaged during the Canterbury earthquakes
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Southside Photograph
Underside Photograph
Load-Drift Hysteresis 800
Total Lateral Force (kN)
Identification and Observations Unit: H1 Date: 24 April 2013 Cycle: 0.25 Target/Net Drift: +0.30% / +0.12% Cracks (red): underside West interface,
