Experimental investigation on the semi-rigid behaviour of aluminium alloy gusset joints

Aluminium alloy gusset (AAG) joints are typical semi-rigid joints widely used in single-layer reticulated shells. Despite the semi-rigid behaviour of the AAG joints, structural analyses still show that dangerous situations can occur. To study the semi-rigid performance of the AAG joints, experiments on fourteen AAG joints are conducted. Initially, the failure modes of the AAG joints are summarised in terms of their collapse phenomena and the stress distributions of the plates are discussed based on the measured strain. Subsequently, the primary characteristics of the M-φ curves of the AAG joints are obtained. The bending stiffness properties of AAG joints are also investigated. The experimental results indicate the following: (1) the primary failure modes include member rupture, member buckling, block tearing of the top plates and local buckling in the bottom plates; (2) the moment-rotation relationship of the AAG joints exhibits a significant inelastic response; and (3) as the thickness of the gusset plate increases, the initial stiffness of the joint increases.