Moment-Carrying Capacity of Dovetailed Mortise and Tenon Joints with or without Beam Shoulder

Abstract

This study aimed to evaluate the influence of beam shoulder on the moment-carrying capacity of traditional post-beam joints, dovetailed mortise, and tenon joints. The specimens were manufactured by a computer numerical controlled (CNC) cutting machine with Japanese larch six-ply glulams (glued laminated timber), and moment-carrying capacity was investigated by static loading tests. The results of the tests indicated that the moment resistance, joint stiffness, and failure modes were different with or without beam shoulder. The results also indicated that all joints types underwent significant deformation without breaking and maintained after the yield point. The failure mode, which included post splitting, shear failure of mortise branches, or embedment failure of tenon, was dependent on the presence of the beam shoulder. The results indicated that the beam shoulder significantly affected the performance of the post-beam joint. It was concluded that the beam shoulder reinforced the dovetailed mortise and tenon joints. Hence, the beam shoulder must be considered as an important factor in the structural design of traditional post-beam joints.