Mechanical behavior of TOBs bolted T-stubs with thick arc-shaped flange to steel tube under tension: A numerical and theoretical investigation

Abstract

The Thread-fixed One-side Bolt (TOB) is a novel fastener proposed in recent years that can easily connect steel beam to circular tubular column through an arc-shaped endplate. Based on the component method, the tension zone of the steel beam to circular column joint can be substituted by the TOBs bolted arc-shaped T-stub to circular steel tube connection. Following the experimental study on such connections in tension reported previously, the tensile behavior of the TOBs bolted T-stubs with thick arc-shaped flange to steel tube connection is further investigated numerically and theoretically in this paper. Based on a validated Finite Element (FE) model, parametric studies are conducted to explore the effects of critical parameters on the mechanical performance of the connection, including the wall thickness and outer diameter of the steel tube, bolt diameter, bolt layout, and tube length. A total of four failure modes appear in the FE analysis, which are (1) complete yielding failure of tube wall, (2) thread shear failure with yielding of tube wall, (3) thread shear failure, and (4) bolt shank failure. The diameter and wall thickness of the steel tube are the main parameters affecting the tensile behavior of the connection. In addition, based on the theoretical investigation, design methods are proposed to predict the initial stiffness, yield strength, and ultimate strength of the connection under different failure modes. The design methods are evaluated by comparing the predicted results with the FE results, which show good agreement.