Finite Element Analysis of Distortion-Induced Web Gap Stresses in Multi-I Girder Steel Bridges


  • Akhrawat Lenwari Chulalongkorn University
  • Huating Chen Beijing University of Technology



Distortion-induced stress, web gap cracking, parametric study, composite I-girder bridge, finite element method.


Unstiffened girder web gaps at the ends of transverse stiffeners that also serve as diaphragm connection plates are subjected to high local stresses during cyclic out-of-plane distortion. The out-of-plane distortion is mainly caused by the differential deflection between adjacent girders. The purpose of the paper is to investigate the effects of bridge parameters including span length, girder spacing, slab thickness, and girder stiffness on the differential deflection and distortion-induced web gap stresses. Dual-level finite element analyses that consist of both global model and sub-model were performed. The global model was used to investigate the critical truck position and maximum differential deflection between adjacent girders, while the sub-model was used for the critical web gap vertical stress. A base case bridge was a simply supported composite superstructure with three steel I-girders that support two traffic lanes, which is typical for steel bridges over intersections in Bangkok, Thailand. A parametric study was conducted by varying one bridge parameter at a time. The analysis results show that the maximum differential deflections and web gap stresses caused by one-truck loading are higher than those caused by two-truck loading (one truck on each lane). Under one-truck loading, the maximum web gap stress occurs at the interior girder. In addition, both the differential deflections and web gap stresses are primarily dependent on the bridge span length.


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Author Biographies

Akhrawat Lenwari

Department of Civil Engineering, Faculty of Engineering, Chulalongkorn University, Bangkok 10330, Thailand

Huating Chen

Institute of Road and Bridge Engineering, Department of Civil Engineering, Beijing University of Technology, Beijing 100124, P. R. China


Published In
Vol 17 No 1, Sep 10, 2012
How to Cite
A. Lenwari and H. Chen, “Finite Element Analysis of Distortion-Induced Web Gap Stresses in Multi-I Girder Steel Bridges”, Eng. J., vol. 17, no. 1, pp. 95-110, Sep. 2012.

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