Overview. - Introduction and Case Study Description. - Field Measurements and FEA Predictions. - M-V-P Interaction. - Conclusions ...
Interaction Between Patch Loading, Bending, and Shear in Steel Girder Bridges Erected with the ILM T. A. Sánchez, ADSTREN, Quito, Ecuador A. Robalino, ADSTREN, Quito, Ecuador C. Graciano, UNAL, Medellín, Colombia
PDH#43348
Overview -
Introduction and Case Study Description Field Measurements and FEA Predictions M-V-P Interaction Conclusions
Introduction and Case Study Description
Introduction and Case Study Description Simón Bolívar Ave., Quito, Ecuador
Los Pájaros Bridge
Villorita Bridge
Carapungo Interchange
Introduction and Case Study Description •
Los Pajaros Bridge has two superstructures in parallel, composed of five and four steel I-girders
Introduction and Case Study Description Bridge Cross-Section:
Introduction and Case Study Description Sequence of Launching Operations:
Introduction and Case Study Description •
The incremental launching method (ILM) is used to cross over an obstacle with minimal intervention from below
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The superstructure is assembled behind one abutment and then, it is pushed forward When proper considerations are taken, the steel erection with ILM can be safer, faster, and more cost-effective than other methods However, the steel girders may be subject to high strength demands
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Is there interaction between major-axis bending, shear, and patch loading (M-V-P)?
Introduction and Case Study Description
AASHTO Required Strength Checks The AASHTO Bridge Design Specifications require checking the following limit states for construction of steel I-girder bridges:
- Compression flange yielding
fbu f f Rh Fyc
- Compression flange stability
fbu f / 3 f Rh Fnc
- Web bend-buckling
fbu f Fcrw
- Tension flange yielding
fbu f f Rh Fyt
- Web shear strength
Vu vVcr
- Maximum level of fl
fl ≤ 0.6Fyf
AASHTO Required Strength Checks When the girder webs do not have bearing stiffeners and are subject to concentrated loads, the AASHTO Bridge Design Specifications require checking two additional limit states: - Web local yielding
Ru b Rny
- Web crippling
Ru b Rnc
Field Measurements and FEA Predictions
Field Measurements and FEA Predictions • A total of 20 strain gauges (vibrating wires) were installed in three different sections
Field Measurements and FEA Predictions
Field Measurements and FEA Predictions
M-V-P Interaction
M-V-P Interaction • P-V, P-M, M-V interaction has been investigated for more than four decades • AASHTO/AISC provisions require to check M, V, and P separately • There is only one model available for M-V-P interaction
M-V-P Interaction
Conclusions
Conclusions • • •
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The ILM is a convenient method to erect steel girder bridges It is safer and faster than other conventional construction methods High stress levels at the cantilever support may be present during the launching process Two-dimensional stress fields due to point load, bending, and shear effects are present in the region around the support The interaction between these stresses may be checked using the Braun and Külhmann equation
Quiz In bridges erected with the ILM, large stress concentrations occur at: a) The free end of the cantilever b) At the cantilever support c) At mid-span
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Questions? PDH # 43348
