Study on failure modes of steel truss bridge gusset plates related to tension and shear block failure

Tension and shear block failure is a limit state which occurs in the connection of tension steel members. The failure mechanism is a combination of tensile failure on one plane and shear failure on the perpendicular plane. The design strength equations for the tension and shear block failure are described in the well known design codes. However, they provide inconsistent levels of safety when they are used in different types of connections. In this paper, the authors survey the design strength equations in the various codes. Then, the pertinent strength equations for the gusset plates of steel truss bridges are selected. Moreover, the authors propose a pair of strength equations for compression and shear block failure for gusset plates subjected to compressive force. And to examine the applicability of proposed equations and to investigate the mechanical behavior of compression gusset plates, parametric analyses on the various thicknesses of gusset plates were conducted.