Seismic behavior of hybrid coupled wall system with replaceable endplate-steel coupling beam

The hybrid coupled wall (HCW) with steel coupling beam (CB) has been widely used in high-rise buildings due to its good ductility and energy dissipation capacity. The HCW with replaceable CB is an optimal component to recover buildings promptly after a severe earthquake. However, the seismic behavior of the HCW with replaceable CB and the reasonable reinforcement ratio in connections to satisfy the design concept of replaceable structure have not been investigated. In this study, a novel HCW subassembly with replaceable endplate-steel CB having different reinforcement ratios in the connections was proposed and tested under cyclic loading. Then, an identical CB was reinstalled and the replaced HCW system was also tested. The results showed that increasing the horizontal or vertical reinforcement ratio in connections significantly enhanced the seismic behavior of HCWs, ensuring the CB to act as a fuse during the test. Increasing the vertical reinforcement ratio could effectively provide a constraint effect on anchor bars and ensure the wall pier to remain elastic, thus satisfying the replaceable requirements. Additionally, the replaced HCW showed similar seismic behavior to the virgin one. Lastly, relevant design methods and recommendations are proposed for the HCW with replaceable CB according to the test results.