Finite element analysis and design of steel corner gusset plates with double row of bolts for net section rupture in braced frames and truss bridges

Abstract

Gusset plates are subjected to complex stresses and obtaining the design thickness is not straight forward as the stresses depend upon the thickness of gusset itself. In this study, a typical case of a corner gusset plate connected to tension member (bracing / diagonal) in a braced frame or a truss girder bridge is considered. It is assumed that the gusset plate is welded at the beam-column joint in a braced frame or at corner joint of a truss girder bridge and connected to the tension member by bolts in double row. Simple 2-D model of gusset plate is developed and non-linear finite element analysis is carried out with the help of ANSYS, a commercial finite element software, for varying load magnitudes. Four, six and eight bolt cases are analyzed. On performing several trails the required thickness of gusset to prevent net section rupture as per the non-linear analysis is noted based on the obtained von-Mises stresses and plastic strains for all the cases. Later the required thicknesses of gusset plates as per Whitmore’s theory and Indian, European, American and Canadian codes of practice are also calculated. Significant discrepancy was noted between the results of finite element analysis, Whitmore’s theory and the various codes of practice considered in this study. On examining the obtained results, probable design thicknesses of gusset plates are proposed for each case. The presented design thicknesses may be useful as a reference / guide for design engineers in fixing the initial thickness of gusset plate to prevent ‘net section rupture’.