Behavior and Design Strength of Block Shear in Steel Lap Joints with High-Strength Steel

Abstract

Bolting is a common connecting method in steel construction. In steel structures, block shear rupture is one of the very critical failure modes of bolted connections. The block shear failure is that shear failure and perpendicular tension failure simultaneously occur in the bolted connection. Although abundant test results on the block shear of bolted connections are available, the failure mechanism is not clearly explained. Since AISC Specification 1978, the design equation for block shear failure have continued to change in various forms. Design equation of current codes including AISC 2010 propse considerably conservative design strength of block shear rupture and inaccurately predict the failure mode. The application of high-strength steel for structural members has diverse technical advantages from design to construction. As the current design equation of the block shear is based on the experiments with conventional steels, the applicability of the high-strength steel for current design standards are unconfirmed. In this study, the behavior of bolted connections with the high-strength steel, HSA800, was experimentally evaluated. In order to better understand and describe the failure mechanism of the block shear and its capacity, 10 lap joints fabricated from conventional and high-strength steels were tested in this study. Numerical analyses of bolted connections were conducted using the general-purpose finite element (FE) software, ABAQUS. Key test variables included the grades of the steels, the geometrical configuration of the number of bolts and distance. This study evaluated the design criteria for the block shear and the applicability of the high-strength steels. Based on the experimental results and the finite element analysis, a new design equation for the block shear applicable to both the convention and high-strength steel was suggested.