Research on flexural performance of glulam spliced joints connected by self-tapping screws in different arrangements

Abstract

Tests were conducted to determine the flexural bearing capacities of glulam spliced joints connected by self-tapping screws (STSs) in five different configurations. The flexural performances and failure modes of these joints were analyzed and an extended finite element method was utilized to establish numerical models of the STS-connected glulam spliced joints while considering crack propagation. The simulation results were in excellent agreement with the test. Moreover, theoretical formulas for the flexural bearing capacity and a flexural stiffness model of STS-connected glulam spliced joints were developed. The research findings indicated that the vertical STSs were more effective in enhancing the bending capacity of the joints than the angled STSs in the vertical plane. Specifically, when using full 90° STSs, the bending capacity increased by 35.57% compared to when using full 60° STSs. The elastic rotational stiffness values of the joints were also improved by using a mixed-angle arrangement of STSs. Specifically, when utilizing a mixed arrangement of 90° and 60°, the elastic stiffness values increased by 33.44% and 63.20% compared to when using full 90° and full 60°, respectively. However, while using STSs in the horizontal plane at the vertical gap significantly enhanced the flexural bearing capacities of the spliced joints, it also led to a significant reduction in the ductility of the joints.