Aug 12, 2012 ... Opinions presented are those of the author. Steel Plate Shear Walls. (SPSW).
Example of. Implementation. (USA). CourtesyTony Harasimowicz ...
8/12/2012
STEEL PLATE SHEAR WALLS (SPSW), TEBF, CFST, SF, AND OTHER SHORT STORIES Michel Bruneau, Ph.D., P.Eng Professor Department of Civil, Structural, and Environmental Engineering
Introduction Focus on SPSW (incl. P-SPSW, SC-SPSW), CFST, CFDST (and maybe a bit more) Broad overview (References provided in NASCC paper for more in-depth study of specific topics) Additional technical information can also be found at www.michelbruneau.com and in “Ductile Design of Steel Structures, 2nd Edition” (Bruneau et al. 2011)*.
* Subliminal message: This book will give you ultimate reading pleasure –buy 100 copies now!
Acknowledgments - 1
Acknowledgments - 2
Graduate students:
Sponsors:
Samer El-Bahey (Stevenson & Associates)
National Science Foundation (EERC and NEES
Programs)
Jeffrey Berman (University of Washington, Seattle) Daniel Dowden (Ph.D. Candidate, University at Buffalo)
New York State
Pierre Fouche (Ph.D. Candidate, University at Buffalo)
Federal Highway Administration,
Shuichi Fujikura (ARUP)
American Institute of Steel Construction
Michael Pollino (Case Western Reserve University)
Engineer Research and Development Center (ERDC) of
the U.S. Army Corps of Engineers
Ronny Purba (Ph.D. Candidate, University at Buffalo)
MCEER, NCREE, Star Seismic, and Corus Steel.
Bing Qu (California Polytechnic State University) Ramiro Vargas (Technological University of Panama) Darren Vian (Parsons Brinkerhoff)
See others at www.michelbruneau.com This support is sincerely appreciated. Opinions presented are those of the author.
Example of Implementation (USA)
Steel Plate Shear Walls (SPSW) ( ) Infill (Web) Column (VBE) Beam (HBE)
CourtesyTony Harasimowicz, KPFF, Oregon
1
8/12/2012
Examples of Implementation (USA)
Examples of Implementation (USA)
LA Live 56 stories
Courtesy Lee Decker – Herrick Corporation, Stockton, CA
Analogy to TensionTension-only Braced Frame
Flat bar brace Very large brace slenderness l d (e.g. ( in i excess of 200)
Courtesy of GFDS Engineers, San Francisco, and Matthew Eatherton, Virginia Tech
V
Analogy to TensionTension-only Braced Frame
Steps to “transform” into a SPSW 1)) Replace p braces byy infill plate (like adding braces)
Analogy to TensionTension-only Braced Frame
V
Anchor Beam
Pinched hysteretic curves Increasing drift to dissipate further hysteretic energy Not permitted by AISC Seismic Provisions Permitted by CSA-S16 within specific limits of application
Steps to “transform” into a SPSW 1)) Replace p braces byy infill plate (like adding braces) 2) For best seismic performance, fully welded beam-column connections
V
2
8/12/2012
Berman/Bruneau June 12 2002 Test End--Result End
Cyclic (Seismic) behavior of SPSW Sum of z
z
V
Fuller hysteresis provided by moment connections Stiffness and redundancy provided by infill plate
L/tw = 3740 h/L = 0.5 (centerline dimensions)
Example of Structural Fuse
600
Base Shear (kN)
400 200 0
-200 -400
Specimen F2 Boundary Frame
-600 600
-3
-2
-1
0 Drift (%)
1
2
3
-3
-2
-1
0 Drift (%)
1
2
3
Base Shear (kN)
400 200 0
-200 -400 -600
Forces from Diagonal Tension Field
ωV = σ t cos2(α) ωH = σ t sin(α) cos(α) = ½ σ t sin(2α) FH = ωH L = ½ σ L t sin(2α)
Knowing L, σy, and α, Can calculate needed thickness (t)
σ ·t
Brace and Strip Models α
PANEL TENSION FIELD STRESS ACROSS UNIT
UNIT PANEL WIDTH ALONG DIAGONAL
V =P··cos α
DIAGONAL WIDTH,
α
P = σ · t · ds H =P·sin α
σ
θ
RESULTANT TENSION FIELD FORCE, P AND COMPONENTS
tw i =
ds
α
ωV =V /dx
SPSW WEB PLATE
ωH =H /dx dx
UNIT
LENGTH
ALONG BEAM
HORIZONTAL, ωH, AND VERTICAL, ωV, DISTRIBUTED LOADING
SPSW HBE
2 Ai sin θi sin 2 θi L sin 2 2 αi hs
hs
L
Equivalent Brace Model (Optional)
L
Strip Model
3
8/12/2012
Strip Model
Strips models in retrofit project using steel plate shear walls
Developed by Thorburn, Kulak, and Montgomery (1983), refined by Timler and Kulak (1983)) V ifi d experimentally Verified i t ll by b z z z
Elgaaly et al. (1993) Driver et al. (1997) Many others Courtesy of Jay Love, Degenkolb Engineers
AISC Guide Design of SPSW (Sabelli and Bruneau 2006 2006))
Recent Observations on SPSW (Bruneau et al. 2011)
Review of implementations to date Review of research results Design requirements and process Design examples z z
Region of moderate seismicity Region of high seismicity
Other design considerations (openings, etc.)
Capacity design from Plastic Analysis z
Demands on VBEs
z
Demands on HBEs
Flexibility Factor Factor’ss purpose HBE in-span yielding RBS connections in HBEs
P-SPSW (reduced demands) Repair and drift demands
Plastic Analysis Approach
Yielding strips Plastic Hinges
Used to develop Free Body Diagrams of VBEs and HBEs
For design strength, neglect plastic hinges 4⋅M p 1 contribution V = 2 ⋅ Fy ⋅ t ⋅ L ⋅ sin 2α + h
4
8/12/2012
Capacity Design of VBE
Capacity Design of VBE
Flexibility Limit Issue
Importance of Capacity Design
Lubell et al. (2000) observed poor behavior of some SPSWs (pull-in of columns) Others suggested flexibility limit desirable to prevent slender VBEs
SPSW-4 UBC Test (Lubell et al. 2000)
SPSW-2 UBC Test (Lubell et al. 2000)
Flexibility Limit (cont’d)
Plate girder analogy
Flexibility Limit (cont’d)
Flexibility factor o
ηo o
Steel Plate Shear Wall
Plate Girder
(ηu −ηo )max = where
ωt = 0.7hsi 4
twi 2Ic L
δ
ηu hs
V
Flange can be modeled as a continuous beam on elastic foundation ⎛ ⎛ω sin ⎜ t εgL ⎜ ⎝ 2 ⎜1 − sin 2 α ⎜ ⎛ ωt ⎜ sin ⎜ 2 ⎝ ⎝
⎞ ⎛ ωt ⎞ ⎛ ωt ⎞ ⎛ ωt ⎟ cosh ⎜ 2 ⎟ + cos ⎜ 2 ⎟ sinh ⎜ 2 ⎠ ⎝ ⎠ ⎝ ⎠ ⎝ ⎞ ⎛ ωt ⎞ ⎛ ωt ⎞ ⎛ ωt ⎟ cos ⎜ 2 ⎟ + sinh ⎜ 2 ⎟ cosh ⎜ 2 ⎠ ⎝ ⎠ ⎝ ⎠ ⎝
⎞⎞ ⎟⎟ ⎠⎟ ⎞⎟ ⎟⎟ ⎠⎠
Increase in streess
Infill Panel
I-Beam Plate Girder
Empirically based flexibility limit:
ωt = 0.7hsi 4
0.9
x
xu
Flange
ωt ≤ 2.5
1.0
L
u
ω t = 3.35
Other specimens that behaved well:
α
Stiffner
Infill Panel
UBC SPSW-2 and SPSW-4:
0.8 07 0.7
twi ≤ 2.5 2I c L
Solving
0.6 0.5
0.00307twi hsi 4 L Introduced in the CAN/CSA S16-01 and 2005 AISC Seismic Provisions Ic ≥
0.4 0.3 0.2
20%
0.1 0.0 0
0.5
1
1.5
2
ωt
2.5
3
3.5
4
5
8/12/2012
Column Design Issues (cont’d)
Flexibility Limit (cont’d)
Prevention of In-Plane Shear Yielding
SPSWs tested by Tsai and Lee (2007) exceeded flexibility limit, yet performed comparably to SPSWs meeting limit
Evaluation of previous specimens
z
Case
Specimen Number of identification stories
Researcher
ωt
Vn
Vsap 2000
Vu − design
(kN)
(kN)
(kN)
Shear Yielding
(i) single-story specimen 1Driver Lubell al (2000)ω =1.73SPSW2 Park et al,et1997, t
2
Berman and Bruneau (2005)
F2
3.35 et1 al, 2007
1 1.01 ωt=1.58
75
108
113
932
259
261
Yes No
766
1361
1458
Yes
(ii) multi-story specimen-a 3
Driver et al (1998)
-b
4
1 73 1.73
4
Park et al (2007)
SC2T
3
1.24
Park et al, 2007, ωt=1.62 676
1011
5
SC4T
3
1.44
999
984
1273
No
6
SC6T
3
1.58
999
1218
1469
Yes
7
WC4T
3
1.62
560
920
1210
Yes
8
WC6T
3
1.77
560
1151
1461
Yes
9
Qu and Bruneau (2007)
b
-
2
1.95 2881
1591
2341
No
10
Tsai and Lee (2007)
SPSW N
2
2.53
968
776
955
No
SPSW S
2
3.01
752
675
705
No
11 a b
SPSW S (ωt=3.01>2.5)
SPSW N (ωt=2.53>2.5)
999
For multi-story specimens, VBEs at the first story are evaluated. Not applicable. Lubell et al, 2000, ωt=3.35
1.2
Excessive flexibility example
1F Drift = 0.2%
σ / fy
1.0
σ / fy
0.8 0.6 0.4 0.2
8.0E+005
0.0 1.2
6.0E+005
1F Drift = 0.3%
1.0
4.0E+005
Specimen: Two-story SPSW (SPSW S) Flexibility factor: ωt=3.01 =3 01 Researchers: Tsai and Lee (2007)
2 0E+005 2.0E+005 0.0E+000
σ / fy
Base Shear (N)
1.0E+006
0.8 0.6 0.4 0.2 0.0 1.2
3.5E+006
o lα
x
1F Drift = 0.6%
1.0
3.0E+006 2.5E+006
0.8 0.6 0.4 0.2
2.0E+006
0.0 1.2
1.5E+006
1F Drift = 2.0%
1.0
Specimen: Four-story SPSW Flexibility factor: ωt=1.73 Researcher: Driver (1997)
1.0E+006
0.8 0.6
Lee and Tsai (2008)
0.4
Driver (1997)
0.2
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5 5.0 5.5 1F Drift (%)
0.0 0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.0
x/lα
HBE Moment Diagram
SPSW
2.0 ωybi+1
Compression ω strut between columns Resultant forces from yielding (x) of strips
fish plate
web of intermediate beam
flange of intermediate beam
d
(B)
xbi
ωybi L V
+
V
V
-
V
ωybi-ωybi+1
o
Vv
κ=0.0 κ=0.5 κ=1.0 κ=1.5 κ=2.0 Maximum
1.5
ωxbi+1
0.4
1.2
0.0E+000
0.6
0.0
1.2E+006
5.0E+005
HBE FBD
0.8
0.2
σ / fy
Tension Fields
σ / fy
Theoretically, with infinitely elastic beam/columns, could purposely assign high L/h ratio and low stiffness to the boundary elements (Bruneau and Bhagwadar 2002) Truss members 1 to 8 in compression as a result of beam and column deflections induced by the other strips in tension – entire tension field is taken byy the last four truss members. Behavior even worse if bottom beam free to bend. This extreme (not practical) example nonetheless illustrates how non-uniform yielding can occur
Base Shear (N)
1F Drift = 0.1%
1.0
+
(ωybi+ωybi+1)(d+2hf )/2
Normalized Moment:: M(x) / (ωL2/8)
No
1.0 0.5
Optional Alternative: RBS at HBE ends In-Span HBE Hinging
0.0 -0.5 -1.0 -1.5
o
-2.0 V h(x )
-
0
0.1
0.2
0.3 0.4 0.5 0.6 0.7 Fraction of span from left support
0.8
0.9
1
Design for wL2/4
6
8/12/2012
Case Study: Design Outputs W16x36
W18x76
(0.88)
(0.99)
Monotonic Pushover Sway and Beam Combined Mechanism L1θ / L2 + θ
L1θ / L2 + θ
ns
∑V H
W16x89 (0.98)
tplate = 0.036 in S = 19.69 in Astrip = 0.72 in2
(0.98)
W16x89
W16x40 (0.96)
(0.96)
W16x40
10 ft
tplate = 0.036 in S = 19.69 in Astrip = 0.72 in2
L2
L1
Δi+2 Vi+2
i =1
i
i
⎛ Lp ⎞ ⎟ =2⎜ ⎜ ⎟ ⎝ L p − L1 ⎠
ns
∑M i =0
pbi
Plastic Hinge on the HBEs Δi+1 ns ns 1 1 + ∑ Fyp L p (t wi − t wi +1 ) sin (2α ) H i − ∑ Fyp t wi L1 sin (2α ) H i i =1 2 i =1 2
x76 W18x (0.99 9)
Vi+1
tplate = 0.059 in S = 19.69 in Astrip = 1.17 in2
(0.99 9)
tplate = 0.059 in S = 19.69 in Astrip = 1.17 in2
x76 W18x
W14x61 (0.99) x50 W18x (0.91 1)
(0.91 1)
10 ft
W18x x50
W12x22 (0.98)
ωb Hi+2
ωc
Horizontal component of the strip yield forces
(0.95) tplate = 0.072 in S = 19.69 in Astrip = 1.42 in2
(0.96)
tplate = 0.072 in S = 19.69 in Astrip = 1.42 in2
W24x62 (0.91)
W24x117 (0.98)
20 ft
20 ft
Hi+1
θ
α
L2
L1
L1 ns L + ∑ Fyp (t wi L2 − t wi +1 L p ) cos 2 α 1 2 i =1 2
Vertical component of the strip yield forces
Hi
Plastic Hinge
SPSW-CD
SPSW-ID
+ Fyp t w1 L2 cos 2 α
Vi
W24x146 (0.96)
(0.92) W24x146
W12x45
W24x62 (0.99)
10 ft
W24x62 (0.99)
Δi
W12x19
Strips remained elastic
Lp
Case Study: Strength per this plastic mechanism is 13% less than per sway mechanism
Design HBEs for wL2/4
Cyclic Pushover Analysis
Cyclic Pushover Analysis
• Monotonic: in-span plastic hinge + significant HBE vertical deformation • Cyclic: to investigate whether phenomenon observed in monotonic analysis may lead to progressively increasing deformations 4%
10.8
3%
7.2
2%
3.6
1%
0
0%
-3.6
-1%
-7.2
-2%
Vertical Displac cement (in) .
14.4
Lateral Drift (%)
Top Floor Displacement, Δ (in)
• Loading history:
-4%
-3%
2
3
4 Number of Cycles, N
5
Æ Significant accumulation of plastic incremental deformation on SPSW-ID
• Maximum Rotations: SPSW-ID = 0.062 radians SPSW-CD = 0.032 radians
SPSW-CD
-2.5
SPSW-ID
-3.0 10.8
14.4
Plastic Analysis Approach
SPSW-ID
0.0
-1.0
HBE2
Yielding strips Plastic Hinges
1.0 SPSW-CD
M/M p
0.5 0.0 -0.5
deserve more attention in future research
-7.2 -3.6 0 3.6 7.2 Lateral Displacement (in)
HBE3 Vertical Displacements
6
-0.5
• AISC 2005 Seismic Specifications: Ordinary-type connections be used in SPSW
ÆTime history analyses show same behavior, with vertical displacements increasing with severity of ground excitation level
0.5 M/M p
• Curves bias toward one direction
1.0
4%
-2.0
Cyclic Pushover Analysis • Comparing rotation demands at beam to column connection
3%
-1.5 15
-4% 1
2%
-1.0
-3%
-14.4
Lateral Drift -1% 0% 1%
-0.5
-14.4 -10.8 -10.8
-2%
0.0
-1.0 -2.5
HBE2
-2.0
-1.5
-1.0
-0.5
0.0
0.5
1.0
θ / θ 0.03
Normalized Moment Rotation (θ/0.03)
For design strength, neglect plastic hinges 4⋅M p 1 contribution V = 2 ⋅ Fy ⋅ t ⋅ L ⋅ sin 2α + h
7
8/12/2012
Single Story SPSW Example
Plastic Analysis Approach
Design
Interpretation #2: Lateral load Vu=
α h
Interpretation #1: Lateral load Vu=
L
Force assigned to infill panel
V =
4⋅M p 1 ⋅ Fy ⋅ t ⋅ L ⋅ sin 2α + 2 h
κ ⋅Vdesign =
Single Story SPSW Example 2.25 2.00
50000 Overstrength from capacity design
40000
1.50
Weighht (lb)
Vplastic/ Vd design
1.75
Case Study
α = 45D β = 1.0
L/h=0.8 L/h=1.00 L/h=1.5 L/h=2 L/h=2.5
1 f yp t w Lh sin ( 2α ) 2
1 25 1.25
30000 20000
1.00
Balance point
0.75
⎡
κ balance = ⎢1 + ⎢⎣
0.50
⎤ 1L β ⋅ ⎥ 2 h 1 + 1 − β 2 ⎥⎦
10000
−1
0 AISC
Design force to be assigned to boundary moment frame
0.25
PROPOSED Panel HBE
VBE
75% Total
40%
0.00 0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
κ
Quantifying Performance
Seismic Performance Factors Parameter
• Time history analyses of SPSWs designed with various k value revealed different drift response • Need to rigorously quantify significance in terms of seismic performance • FEMA P695 procedure is a useful tool for that purpose
SW320
SW320K
Reference
1. Design Stage R
7
7
ATC63 Design 3-Story SPSW Big Size 100%.xls
176
176
ATC63 Design 3-Story SPSW Big Size 49%.xls
Vmax
495
226
δy,eff
1.80
1.8
δu
8.86
8.64
Ω = Vmax/Vdesign
2.81
1.29
μT = δu/δy,eff
4.92
4.80
SCT
3.60
2.29
IDA Curve for SW320 Sa PDGravity+Leaning.xls
SMT
1.50
1.50
IDA Curve for SW320K Sa PDGravity+Leaning.xls
CMR = SCT/SMT
2.40
1.53
Vdesign 2. Nonlinear Static (Pushover) Analysis
Pushover Curve for SW320 and SW320K.xls Included SH = 2%, Ωd = 1.2 and φ = 0.9
3. Incremental Dynamic Analysis (IDA)
8
8/12/2012
Typical Archetype Model
Component Degradation Model
OPENSEES Model:
M
• Fiber Hinges on HBE and VBE ends
My
P
Mcap SH = 2%
Py
EI
• Axial Hinges on Strips
EA
-θy θy Symmetri c
• Gravity loads applied on SPSW according to its tributary area.
0.081
0.039 0.064
θ
δy No Compression Strength
-My
(a) Boundary Elements
• Remaining loads applied on Leaning columns
Pcap SH = 2%
9.0δy 10.7δ
δ
y
0.015 0.018 (Axial Strain)
(b) Strips
Failure mode developed based on 33 previously tested SPSW specimens Degradation model verified on 1 to 4 story SPSW specimens
Dual Strip Model
P-Δ Leaning Column
Incremental Dynamic Analysis (IDA) Results - Sa
Seismic Performance Factors
SW0320
Parameter
SW320
SW320K
Reference
1
1. Design Stage R
Probability off Collapse
0.8
SW0320K
7
7
ATC63 Design 3-Story SPSW Big Size 100%.xls
176
176
ATC63 Design 3-Story SPSW Big Size 49%.xls
Vmax
495
226
δy,eff
Vdesign 2. Nonlinear Static (Pushover) Analysis
0.6
1.80
1.8
δu
8.86
8.64
SW320 Lognormal SW320
Ω = Vmax/Vdesign
2.81
1.29
SW320K Lognormal SW320K
μT = δu/δy,eff
4.92
4.80
SCT
3.60
2.29
IDA Curve for SW320 Sa PDGravity+Leaning.xls
SMT
1.50
1.50
IDA Curve for SW320K Sa PDGravity+Leaning.xls
CMR = SCT/SMT
2.40
1.53
0.4
0.2
0 0
5 Spectral Acceleration, ST (Tn = 0.36 Sec.), g
Seismic Performance Factors, Cont.
10
Pushover Curve for SW320 and SW320K.xls Included SH = 2%, Ωd = 1.2 and φ = 0.9
3. Incremental Dynamic Analysis (IDA)
Fragility Curve: DM (Inter(Inter-story Drift) for SW320 1
Parameter
SW320
SW320K
Reference
4. Performance Evaluation 0.36
0.36
SDC
Dmax
Dmax
FEMA P695 (ATC63) Table 5-1
SSF (T, μT)
1.25
1.25
FEMA P695 (ATC63) Eq. 5-5 FEMA P695 (ATC63) Table 7-1b
1.91
ACMR = SSF (T, μT) x CMR
3.00
βRTR
0.4
0.4
FEMA P695 (ATC63) Section 7.3.1
βDR
0.2
0.2
FEMA P695 (ATC63) Table 3-1: (B - Good)
βTD
0.35
0.35
FEMA P695 (ATC63) Table 3-2: (C - Fair) FEMA P695 (ATC63) Table 5-3: (B - Good)
βMDL
0.2
0.2
βtot = sqrt (βRTR + βDR + βTD + βMDL )
0.60
0.60
ACMR20% (βtot)
1.66
1.66
FEMA P695 (ATC63) Table 7-3
ACMR10% (βtot)
2.16
2.16
FEMA P695 (ATC63) Table 7-3
Statusi
Pass
Pass
FEMA P695 (ATC63) Eq. 7-6
StatusPG
Pass
2
2
2
2
0.8 Probability off Exceedance
T
0.6 DM: 1% Drift DM: 2% Drift DM: 3% Drift
0.4
DM: 4% Drift DM: 5% Drift DM: 6% Drift
0.2
DM: 7% Drift
NOT Pass FEMA P695 (ATC63) Eq. 7-7
DM: Collapse Point
5. Final Results R
7
Try Again
0
Try Again
Design Level Sa = 1.5g
Ω
2.8
μT
4.9
Try Again
7
Try Again
Cd = R
0
2
4
6
8
10
Spectral Acceleration, S T (Tn = 0.36 Sec.), g
9
8/12/2012
Fragility Curve: DM (Inter(Inter-story Drift) for SW320K 1
Perforated Steel Plate Shear Walls (P (P--SPSW)
Probability off Exceedance
0.8
0.6
DM: Drift 1%
(to reduce tonnage of steel in low low--rise SPSWs)
DM: Drift 2% DM: Drift 3% 0.4
DM: Drift 4% DM: Drift 5% DM: Drift 6%
0.2
DM: Drift 7% DM: Collapse Point 0 0 Design Level Sa = 1.5g
2
4
6
8
10
Spectral Acceleration, ST (Tn = 0.36 Sec.), g
Infill Overstrength
Available infill plate material might be thicker or stronger than required by design. Several solution to alleviate this concern z z z
Light-gauge cold-rolled steel Low Yield Steel (LYS) steel Perforated Steel Plate Shear Wall
Perforated Wall Concept 4
3
2
1
A
Specimen P at 3.0% Drift
B
C
D
E
F
Perforated Layout, Cont.
Sdiag
θ
“Typical” diagonal strip
10
8/12/2012
Typical Perforated Strip ((Vian Vian 2005)
Typical Strip Analysis Results (ST1) At monitored strain emax = 20%, D = 100 mm (D/S (D/Sdiag = 0.25)
Sdiag = 400 mm
2δ ABAQUS S4 “Quadrant” Model D (a) Strip Mesh and Deformed Shape (Deformation Scale Factor = 4)
L = 2000 mm
½L
δ (b) Maximum In-Plane Principal Stress Contours
t = 5 mm not actual mesh
D = variable
Sdiag
½ Sdiag
(c) Maximum In-Plane Principal Strain Contours
FLTB Model
FLTB Model: Typical Panel Results At monitored strain εmax = 20%, D = 200 mm (D/ (D/S Sdiag = 0.471)
5.0 Strip emax = 20% Strip emax = 15% Strip emax = 10% Strip emax = 5% Strip emax = 1%
Total Uniform Strrip Elongation, ε un (%)
4.5 4.0 3.5
Panel emax = 20% Panel emax = 15% Panel emax = 10% Panel emax = 5% Panel emax = 1%
3.0 2.5 2.0 1.5 1.0 0.5 0.0 0.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
Perforation Ratio, D/S diag
Maximum In-Plane Principal Strain Contours
Shear Strength vs. Frame Drift 3000
Infill Shear Strength: RF Model 0.9 0.8
2000 1500 1000 500
51.5%
0.7
emax = 20% emax = 15% emax = 10% emax = 5% emax = 1% Solid D050 (D/Sdiag = 0.12) D100 (D/Sdiag = 0.24) D150 (D/Sdiag = 0.35) D200 (D/Sdiag = 0.47) D250 (D/Sdiag = 0.59) D300 (D/Sdiag = 0.71) Bare
Vyp.perf / V yp
Total Shear Sttrength, Vy (kN)
1.0
2500
0.6 0.5 0.4 0.3
⎡ D ⎤ ⋅ V yp V yp. perf = ⎢1 − α Sdiag ⎥⎦ ⎣
Predicted (Eq. 4.3) γ = 5% γ = 4% γ = 3% γ = 2% γ = 1% Linear Reg.
0.2 0.1
correction factor:
0.0
0
0.0
0.0
1.0
2.0
3.0 Frame Drift, γ
4.0
5.0
0.1
0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
α = 0.7
1.0
D/S diag
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8/12/2012
Implementation of P P--SPSW Replaceability of Web Plate in SPSW
Courtesy of Robert Tremblay, Ecole Polytechnique, et Eric Lachapelle, Lainco Inc, Montreal
Experimental Program
Phase I: Pseudo-dynamic load to an earthquake having a 2% in 50 years probability of occurrence. (Chi Chi CTU082EW--2╱50 PGA=0.67g) (Chi_Chi_CTU082EW--2╱50 PGA=0 67g) Cut-out and replace webs at both levels Phase II: Repeat of pseudo-dynamic load to an earthquake having a 2% in 50 years probability of occurrence. Subsequently cyclic load to failure.
Pseudo--dynamic Test (cont’d) Pseudo
Web replacement
Buckled web plate from first pseudodynamic test cut out and new web plate welded in place
Pseudo--dynamic Test (cont’d) Pseudo
1st story
2nd story
Specimen after the maximum peak drifts of 2.6% at lower story and 2.3% at upper story in pseudo-dynamic test.
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8/12/2012
Subsequently Cyclic Test
Subsequently Cyclic Test (cont’d)
Severe plate damage and intermediate beam damage also occurred at drifts between 2.5% and 5%
2nd story after interstory drift of 5% 1st Story after interstory drift of 5%
Self-Centering SPSW Self-Centering Self(Resilient) SPSWs (SC--SPSWs) (SC
Concept: Replace rigid HBE to VBE joint connections of a conventional SPSW with a rocking connection combined with Post-Tension elements. y Energy dissipation provided by yielding
of infill plate only (not shown in figure) y HBE, VBE and P.T. components
designed to remain essentially elastic y Elastic elongation of P.T. about a rocking
point provides a self-centering mechanism
UB Test-Setup (Full Infill Plate Frames)
UB Specimen (Rocking about Flanges)
13
8/12/2012
Accommodating Beam Growth with Large Columns
Courtesy of Greg MacRae, University of Canterbury, New Zealand
NewZ-BREAKSS Rocking Connection Rocking Point (Ea. End of HBE) W6x VBE
Radius Cut-Out Flange Reinf. Plate
UB Test Frame: Additional Test Frame Configurations:
Test Frames w/ Infill Strips
New Zealand-inspired – Buffalo Resilient Earthquake-resistant Auto-centering while Keeping Slab Sound (NewZ-BREAKSS) Rocking Connection
Frame w/ NewZBREAKSS Conn.
NewZ-BREAKSS Rocking Connection
Light Gage Web Plate W8x HBE
Continuity Plate VBE Web Dblr Plate Post-Tension (Ea. Side of HBE Web)
P tT i Post-Tension Eccentricity
Stiffener Plates (Typ.) Cant HBE Web (Ea. End of HBE)
Shear Plate w/ Horiz. Long Slotted Holes
Comments: ¾Schematic detail shown of UB 1/3 test frame connection currently being tested at UB ¾Eliminates PT Frame expansion by HBE rocking at the beam top flanges only
NewZ-BREAKSS Rocking Connection
NewZ-BREAKSS Rocking Connection
14
8/12/2012
UB NewZ-BREAKSS Test Frame
UB NewZ-BREAKSS Test Frame
UB NewZ-BREAKSS Test Results NewZ-BREAKSS Hysteresis Full Infill Plates -3.4 60
-2.7
50 40
Base Shear (kips)
-2.0
0.167Δy 0.33Δy 0.67 Δy 1.0Δy 2Δy 3Δ 3Δy
30 20
-1.4
Top Story Drift (%) -0.7 0.0 0.7 1.4
2.0
2.7
3.4
4Δy 2% drift 2.5% drift 3% drift
Comments: ¾Displacement control at top level actuator with a slaved Force control at level 1 & 2 2.
10
¾Force control load pattern of 1, 0.658, 0.316 at level 3, 2, 1 actuators used based on approximate first mode shape.
0 -10 -20 -30 -40 -50 -60 -5
-4
-3
-2 -1 0 1 2 Top Story Displacement (in)
3
4
5
Discrete Strips Alternative
NewZ-BREAKSS Hysteresis Full Infill Plates - SAP2000 Top Story Drift (%) -4.5
-3
-1.5
0
1.5
3
4.5
80
Base Shear (k (kips)
60 40 20
1) 2) 3) 4)
Test Frame - 2x0.5" strds APT = 4x0.5" strds APT = 6x0.5" strds APT = 6x0.6" strds
0 -20
*Residual Drift 1) 1.85% 2) 1.0% 3) 0.85% 4) 0.58% *modify HBE/VBE sizes as required
-40 -60 -80 -8
-6
-4
-2
0
2
4
6
8
Top Story Displacement (in)
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8/12/2012
UB Test Results – NewZ-BREAKSS Top Story Drift (%) -6 -4.5 -3 -1.5
0
1.5
3
4.5
6
No separation of the infill strips occurred (also observed with the flange rocking case). Testing stopped to be able to reused VBEs for subsequent shake table testing.
60
Base Shear (kips)
SAP2000: 10% Comp.
40 20 0 -20 PT Yielding Occured At Approx. 4.5% Top Story Drift
-40 -60 -10.5 -7.5
-4.5
-1.5
1.5
4.5
7.5
10.5
Top Story Displacement (in)
Eccentrically Braced Frame Tubular-link Eccentrically TubularBraced Frames (TEBF) a.k.a. EBF with BuiltBuilt-up Box Links
Proof--of Proof of--Concept Testing
Tubular--link EBF Tubular
EBFs with wide-flange (WF) links require lateral bracing of the link to prevent lateral torsional buckling Lateral bracing is difficult to provide in b bridge piers Development of a laterally Fyf tw stable EBF link is warranted Fyw Consider rectangular crosstf section – No LTB
d
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8/12/2012
Finite Element Modeling of Proof--of Proof of--Concept Testing
Link Testing – Results Large Deformation Cycles of Specimen X1L1.6
Hysteretic Results for Refined ABAQUS Model and Proof-of-Concept Experiment
Design Space Stiffened Links Unstiffened Links 0.64
1.67
E Fyw
Implementation of TEBF
b tf 0.64
ρ = 1.6
E Fyw d tw
E Fyf
ρ
Some slenderness limits accidentally missing from AISC 341-10
Towers of temporary structure to support and provide seismic resistance i t to t deck d k off self-anchored suspension segment of East Span of SanFrancisco-Oakland Bay Bridge during its construction
Earthquakes
Multi--Hazard Design Concept Multi Why Multi-Hazard Engineering Makes Sense?
17
8/12/2012
Storm Surge or Tsunami
Collision
http://www.dot.state.mn.us/bridge/Manuals/LRFD/June2007Workshop/10%20Pier%20Protection.pdf
Fire
Blast
Suicide truck-bomb collapsed the Al-Sarafiya bridge and sent cars toppling into the Tigris River (AP, (Baghdad, Iraq, April 2007)
Multi--hazard solution Multi
A true multi-hazard engineering solution is a concept that simultaneously has the desirable characteristics to protect and satisfy the multiple (contradicting) constraints inherent to multiple hazards Needs holistic engineering design that address all hazards in integrated framework A single cost single concept solution (not a combination of multiple protection schemes) Pay-off: Reach/protect more cities/citizens
Concrete--Filled Steel Tubes Concrete (CFST) for blast and seismic performance
18
8/12/2012
CFST Piles
“The Loma Prieta and Northridge earthquakes in California and the Kobe, Japan quake, along with reexamination of largediameter cylinder-pile cylinder pile behavior in the Alaskan earthquake of 1964, have demonstrated the superior ductility of concrete-filled steel tubular piles.” (Ben C. Gerwick Jr., ASCE Civil Engineering Magazine, May 1995)
CFST Column Specimen (1st Series)
CFST Column Test Results Test 5: Bent 1, C5 (1.3X, W, Z=0.75m)
16.5”
164” CAP-BEAM C5
C4
68.5”
69.5”
6” 6
5” 5
59”
C6
Bridge carrying Broadway Ave. over the railroad in City of Rensselaer, NY Built 1975. No major rehab, although joints and wearing surface were redone
4” 4
Dmax = 76 mm
32”
FOUNDATION BEAM
Gap = 3 mm
164” Concrete-Filled Steel Tube
Concrete (no rebars)
Damage Progress of CFST Column (Column Deformations) 1.2 deg (0.021 rad)
2.2 deg (0.038 rad)
4.9 deg (0.085 rad)
18.7 deg (0.327 rad)
Fracture of Column
Seismically Designed Ductile Column
10.5 deg (0.182 rad)
5.0 deg (0.088 rad)
21.9 deg (0.382 rad)
Buckling of Steel Tube
Explosion 3.8 deg (0.067 rad)
8.3 deg (0.144 rad)
17.0 deg (0.297 rad)
Fracture of Steel Tube
Covered Concrete
Plastic Deformation (Test 6 : B2-C4)
Blew Away
Plastic Deformation (Test 9 : B2-C6)
On-set of Column Fracture (Test 10 : B2-C5)
Post-fracture of Column (Test7 : B2-C4)
Shear Failure Seismic Design Alone is not a Guarantee of MultiHazard Performance Need Optimal Seismic/Blast Design
19
8/12/2012
Comparison of Blast Parameters
Jacketed NonNonDuctile Column (Seismic Retrofit)
CFST Tests
0.10W Test 5 Test 4
250
750
Test 3 Test 9,10 Test 7
Test 6
Comparison of Column Damage Horizontal Deformation (mm)
Test 1,3 Test 2,4
1
1
1
38
3
59
5
80
7
6
6
10
10
17
15
102 123 144 165
8
19
19
11
21
23
12
24
27
12
28
31
188
13
32
35
216
14
37
39
242
15
40
44
263
16
45
49
285
16
50
52
309
15
52
56
328
16
57
61
347
15
62
65
367
14
67
71
379
All longitudinal bars fractured.
Test 6 CFST C4 (x = 1.6 X)
Test 1 RC1 (x = 2.16 X)
0.7 deg (0.012 rad)
All longitudinal 71 bars fractured. 75
13
74
Standoff Distance (in X)
3 3.25
Calibration Work Fracture of Column
Explosion
Blew Away
250
3.8 deg (0.067 rad)
18
Test 2
Test 1
0.8 1.3 2 0.6 1.1 1.6 2.16
24 (Max)
W
0.55W
Reaction Frame
Again Shear Failure Same conclusions
1.2 deg (0.021 rad)
RC, SJ Tests
W
79
2.9 deg (0.051 rad)
Test 2 RC2 (x = 3.25 X)
Test 3 SJ2 (x = 2.16 X)
Test 4 SJ1 (x = 3.25 X)
Blast Simulation Results
e )
Post-fracture of Column (Test7 : B2-C4)
Proposed Multi Hazard Concept • Analysis of concrete filled double skin tubes (CFDST) showed they can offer similar performance as CFST • CFDST concentrates materials where needed for higher strength-to-weight ratio
20
8/12/2012
Blast Test Results
S1 @ 3% Drift
S1 @ 7.5% Drift
S1 @ 10% Drift
S5 @ 3% Drift
S5 @ 6% Drift
S5 @ 7.5% Drift
Enhanced Steel Jacketed Column
21
8/12/2012
ERDC Test on ESJC • Results
Structural Fuses (SF)
Analogy
structural fuse, d
mass, m
Sacrificial element to protect the rest of the system. frame f frame, braces, b
Ground Motion, üg(t)
Model with Nippon Steel BRBs
Benefits of Structural Fuse Concept:
Seismically induced damage is concentrated on the fuses V V Following a damaging earthquake only the fuses V would need to be replaced VV Once the structural fuses are removed, the elastic structure returns to its original position (self-recentering capability)
Total
Eccentric Gusset Gusset--Plate
p
αK1 = Kf
y
Structural Fuses
K1
yd yf
Ka
Δya
Frame
Kf
Δyf
u
22
8/12/2012
Test 1 First Story BRB
Test 1
(PGA = 1g)
40
1st Story Axiaal Force (kips)
30 20 10 0 -0.5
-0.4
-0.3
-0.2
-0.1
-10
0
0.1
0.2
0.3
0.4
0.5
-20 -30 -40 Axial Deformation (in)
Test 1 (Nippon Steel BRB Frame) First Story Columns Shear 1st Story Column ns Shear (kN)
100
-5
75 50 25 0 -4
-3
-2
-1
-25
0
1
2
3
4
5
-50 -75 -100 Inter-Story Drift (mm)
ABC Bridge Pier with Structural Fuses Specimen S2S2-1
New “Short Length” BRB Developed by Star Seismic
23
8/12/2012
Specimen with BRB Fuses
Specimen with BRB Fuses
Controlled Rocking/Energy Dissipation System
Rocking Frames (RF)
Absence of base of leg connection creates a rocking bridge pier system partially isolating the structure Installation of steel yielding devices (buckling-restrained braces) at the steel/concrete interface controls the rocking response while providing energy dissipation Retrofitted Tower
Existing Rocking Bridges South Rangitikei Rail Bridge
Lions Gate Bridge North Approach
Static, Hysteretic Behavior of Controlled Rocking Pier
FPED=0 FPED=w/2
Device Response
24
8/12/2012
Design Procedure Design Chart:
Design Constraints z
h/d=4 10
Acceleration ⇒
Limit forces through vulnerable members using structural “fuses”
8
6
z
Velocityy Control impact energy to foundation and impulsive loading on tower legs by limiting velocity ⇒
Displacement Ductility Limit μL of specially detailed,
4
2
⇒
ductile “fuses” z
Auub
z
Aub ((in2)
0
0
β