Design and strength evaluation of critical gusset plates in the steel bridge using new load and resistance factor design methods and advanced FE analyses

Abstract

The gusset plates typically employed for connecting steel members to each other in the lateral load resisting systems are always an important part of truss bridges and braced frames. We can recognize that when considering the tragic collapse of the I-35W Minnesota highway bridge on August 1, 2007, the failure of gusset plates in particular leaded to destroy the whole structure. Many researchers have been increasingly interested in the adequate design of such critical panel points as motivated by this accident. In order to follow up on this research trend, this study is intended to examine design strength models on the basis of feasible failure patterns for the gusset plates, thereby calculating their strength capacities. In addition, the inelastic behavior of existing gusset plates is investigated through a series of detailed finite element (FE) analyses, and then strength models specified in the current design specifications are evaluated based on the FE analysis results. According to individual failure modes, safety and load rating factors deliberately applied to gusset plate design are finally assured by observing the distribution of plastic stresses on the gusset plate. © 2013 ISIJ.