Elastic Local Buckling of Trough Girders

Abstract

An elastic finite strip method of analysis is used to study the linear local buckling or bifurcation and the nonlinear post‐local buckling behavior of isolated trough girders in bending. The method assumes a constant stress in the longitudinal direction and so is applicable to the uniform bending case. This results in a solution that is efficient computationally. The nonlinear stiffness equations are presented, and the accuracy of these is demonstrated by a comparison to tests and independent theoretical solutions. The comparison between theory and experiment is good. The variation of the local buckling coefficient with the cross‐sectional parameters is demonstrated, and a design equation is proposed. It is shown that local buckling can be delayed by the provision of a longitudinal web stiffener, and a design equation is proposed. The postbuckling of a typical trough girder is then considered, with the moment‐curvature relationship, stress distribution, and deformations all being addressed in the study.