Seismic performance evaluation of coupled wall system with novel replaceable steel truss coupling beams

Coupled wall systems are often used in high-rise buildings in zone of high seismic risk to provide lateral resistance to earthquake loading. Once damaged, reinforced concrete coupling beams are costly and time-consuming to repair post-earthquake. To enhance the seismic resilience for coupled wall structures, a novel replaceable steel truss coupling beam is first introduced. The proposed replaceable steel truss coupling beam consists of chord members at the top and bottom, respectively, and two buckling-restrained energy dissipaters are employed in the diagonal direction. The energy dissipaters can yield first before the wall piers and dissipate large amounts of energy to protect the main structure under seismic loadings. In addition, the energy dissipaters can be easily installed and post-earthquake repaired through pin connection with the chord members. This article mainly focused on the numerical and theoretical analyses of the proposed replaceable steel truss coupling beam, and nonlinear analytical models were developed in PERFORM-3D. An 11-story prototype structure was designed per Chinese code. The seismic response of hybrid coupled wall system with replaceable steel truss coupling beams was evaluated using nonlinear time history analysis and compared with the response of reinforced concrete coupled wall system with reinforced concrete coupling beams under seismic loadings. Results show that the proposed replaceable steel truss coupling beam leads to a good seismic response with reduced interstory drifts of the systems and rotational demand in the beams and wall piers due to a large energy dissipation capacity and overstrength