Mechanical performance of mortise-tenon joints reinforced with self-tapping screws

Abstract

• Mortise-tenon joints provides a potentially feasible scheme for the development of connection in modern timber construction. • Using self-tapping screw (STS) to reinforce mortise-tenon joint is cost-efficient, convenient, and faster. • The reinforced joints had a better mechanical properties than the unreinforced joint. • The parameters of STS had a significant influence on the reinforcement effect of mortise-tenon joints. This paper presents the results of the mortise-tenon joints reinforced with self-tapping screw (STS) under cyclic loading experiment. Five groups of joints, including one unreinforced group and four reinforced groups, were subjected to low-cycle reversed loading tests, where STS with different diameters and numbers were screwed into the reinforced group. The mechanical behavior of joints such as failure modes, hysteretic and skeleton curves, bending capacities, stiffness, ductility, and energy dissipation were obtained. The results showed that the insertion of STS can effectively reduce the pull-out of tenon and improve the initial stiffness and ductility. The bending capacities of the reinforced groups were significantly improved. In addition, the reinforced groups had a higher energy dissipation capacity in initial cycles under negative loading, while the unreinforced group could maintain a certain energy dissipation capacity during the whole loading process. More STS and a larger diameter of STS could improve the mechanical performance of mortise-tenon joints, but it would also aggravate the damage of joints.