Interaction between patch loading, bending moment, and shear stress in steel girders

In bridge erection, a steel girder undergoing in-plane loading is commonly subjected to the interaction of several forces. Many previous studies have highlighted the effects of single in-plane loads on plate buckling but only a few works concentrated on the combined effects. For this reason, the stability of steel plates subjected to the combined action of patch loading, bending moment, and shear stress was studied through parametric analysis in this work. In particular, the effect of patch loading length combined with bending and shear stress was investigated. Other parameters like patch loading magnitude, panel aspect ratio, and plate slenderness have also been considered to characterize the plate stability. Through an intensive finite element method (FEM) analysis, new design equations have been defined to describe the influence of plate and load parameters on critical buckling loads of plates subjected to combined loads, with regard to plates subjected to patch loading. A comparison with the FEM results offers good accuracy, with a maximum deviation equal to 5%. To validate the analytical equations, a practical example is given.