Influence of the patch loading length on the buckling coefficient of longitudinally stiffened plate girders

Abstract

Currently, one of the most used steel bridge assembly methods is the Incremental Launching Method (ILM). Its practical application consists in passing the bridge assembly through a launching shoe as well as over each support pile. For steel plate girders, a concentrate vertical reaction also known as patch loading is generated over one the flanges when ILM is employed, and depending on the geometrical and material properties of the girder, buckling failure in the web panel may occur. To overcome this type of failure, plate girders are reinforced with longitudinal stiffeners. Therefore, this paper aims at investigating the effect of the bearing length on the elastic buckling behavior of longitudinally stiffened girder webs subjected to patch loading. Buckling coefficients of longitudinally stiffened girder webs are calculated by means of linear finite element analysis. Furthermore, a parametric analysis is performed to study the influence of other geometric parameters such as the panel aspect ratio and the geometrical properties of the longitudinal stiffener on the buckling coefficient. The results show that for longitudinally stiffened girder webs the buckling coefficient increases with the loading length. However, this conclusion is considerably affected by other factors such as the position of the stiffener, and panel aspect ratios.