Mechanical properties of mortise-tenon joints reinforced by self-tapping screws with different insertion methods

The mortise-tenon (MT) joints are kind of traditional connection for structural components in China, which can get better connection performance by reinforcement. In this paper, different self-tapping screw (STS) insertion methods were applied to reinforce the MT joints, and cyclic loading were carried out for one group of unrein-forced joint and three groups of reinforced joints. The load-carrying capacity, strength, stiffness, ductility, and energy dissipation capacity of each group were evaluated. The results showed that STS inserted horizontally could significantly reduce the pull-out of the tenon and improve the load-carrying capacity of the joints. The joints reinforced by two horizontally inserted STS had a higher load-carrying capacity than those reinforced by one STS with horizontal insertion, although the former might accelerate the damage to joints. Inclined insertion of STS for joints provided higher stiffness, ductility and energy dissipation capacity, while the load-carrying capacity was inferior to that of the reinforced joints with STS horizontally inserted. This paper provides data for reinforcing MT joints with STS, so as to select different reinforcement methods for different engineering requirements.