Cyclic axial loading tests on mortar-filled rectangular tube with various connection details

Although a mortar-filled rectangular hollow structural section (RHS) under monotonic loading has achieved large tensile capacity using various connection details and buckling capacity of RHS members, the structural capacity of the mortar-filled RHS tubes has not been investigated under cyclic loading. In this study, the seismic performances of newly developed mortar-filled RHS tubes with various connection details were evaluated under cyclic axial loading. The major test parameters included the end connection type, the thicknesses of the RHS tube, cap plate, and cleat plate, as well as the length of the RHS tube. The test results showed that the RHS tube in all specimens failed by tensile fracture before axial compression failure. The seismic performance of the embedded shear plate end connection with penetrating rebar was superior to that of a conventional welded T-end connection. The test results were compared with the current design code to evaluate the seismic capacity of the RHS tube according to the connection details. Design considerations for the connections of the mortar-filled rectangular tubes were also provided. •Mortar-filled RHS tubes with various details were tested under cyclic axial load.•Tensile fracture of the mortar-filled tubes preceded axial compression failure.•The performance of shear plate end connection was superior to that of T-end joint.•Penetrating rebars improved both tensile and compressive capacities of the member.•The thickness of steel tubes affected failure modes of welded T-end connections.