Design of steel gusset plates

Abstract

Gusset plates are extensively used for connecting various components in a steel structure which play a crucial role in transfer of forces and maintaining structural integrity. Behaviour of gusset plates is very complex and the determination of the required thickness of a gusset plate is not straight forward. Presently, Whitmore’s theory is used to check the thickness of a gusset plate which is provided based on empirical considerations and past experience. Whitmore’s theory may be unconservative and may not be reliable. Hence, an effort has been put to rationally determine the thickness of gusset plates that are commonly used in roof trusses and towers. In this investigation, initiation of rupture is considered as failure rather than complete rupture of gusset plate. It is assumed that rupture initiates when the principal tensile stress on the edge of a bolt hole approaches the ultimate strength of the material. The principal tensile stress on the edge of a bolt hole is obtained by geometric and material non-linear finite element analysis of gusset plates. The minimum thickness required to prevent initiation of rupture is noted. The thickness required for preventing buckling of gusset plates is calculated using Modified Thornton’s theory. The maximum thickness obtained from the non-linear finite element analysis, Whitmore’s theory and Modified Thornton’s buckling theory is specified as the minimum required thickness of gusset plates.