Strengthening of plate girders subjected to patch loading

Localized edge loading or patch loading of bridge girders, is frequently encountered in practice. The behavior of girders under patch loading represents complex stability and elastoplastic problems. In situation where the location of the patch load is fixed, transverse web stiffeners can be used to provide increased resistance, but for economic reasons should be avoided wherever possible. For moving load in some structures such as bridges, it is not possible to provide transverse stiffeners at all critical locations. One option is to use longitudinal stiffeners in these situations. In this article, ANSYS finite element software was used for structural analysis to investigate the ultimate resistance of plate girders subjected to patch loading. The finite element model was validated with experimental results taken from literature and found to be more accurate. Extensive parametric study was also performed to investigate the ultimate resistance of longitudinally stiffened plate girders. Furthermore, the ultimate resistance and the optimum position of the longitudinal stiffeners were presented in closed-form which showed satisfactory correlation with the theoretical results.