Numerical Study of Load Eccentricity Effects on Block Shear Rupture of Welded Gusset Plates

Block shear rupture is a potential failure mode in welded steel gusset plates. The research on this failure mode in welded connections is scarce, and in available few studies, only concentric loading condition has been considered. Nevertheless, gusset plates are often loaded eccentrically, either in-plane or out-of-plane, depending on the connection. This paper examines the block shear failure in welded gusset plates under eccentric loading. First, an advanced nonlinear finite element model with ductile fracture prediction capability was developed and verified in detail against the authors’ experiment. Then, a comprehensive parametric study consisting of 260 connections was performed. Based on the results, the eccentricity of the applied load made the tensile and shear stress distributions on the failure planes uneven. The ratio of the eccentricity to the connection length was the main parameter that affected block shear strength under eccentric loads. In out-of-plane eccentric cases, gusset plate thickness was also a significant factor. Moreover, the findings implied that current block shear strength equations suggested for welded gusset plates did not take into account load eccentricity-induced effects and overestimates the connection capacity. Accordingly, modified design equations are proposed that predict the block shear strength under eccentric loading with greater accuracy.