Experimental Study on Seismic Performance of Hybrid Coupled Wall Systems With Friction Steel Truss Coupling Beams

ABSTRACT The reinforced concrete coupled wall system is a prevalent lateral force‐resisting system for mid‐ to high‐rise buildings. To enhance the seismic performance of such systems, this study proposes a friction hybrid coupled wall (FHCW) system, which integrates friction steel truss coupling beams (FTCBs). The FHCW system is designed with explicit performance objectives across different earthquake levels: it remains elastic under service level earthquakes (SLEs); experiences first and second sliding of the FTCBs during design basis (DBE) and maximum considered earthquakes (MCE), respectively; and allows wall pier reinforcement to yield under very rare earthquakes (VREs). To validate the seismic performance of the proposed system, a large‐scale quasi‐static test was performed on a three‐story subassemblage extracted from a 24‐story prototype. Realistic boundary conditions were simulated by applying varying axial loads to the wall piers. Test results confirmed the predefined performance objectives. Up to the VRE level, wall piers remained elastic, with inelastic deformation concentrated in the replaceable friction dampers of FTCBs. The FTCBs exhibited full and stable hysteretic responses, contributing 67% of the total energy dissipation. Beyond VRE, plastic hinges formed at the wall bases, eventually leading to flexural failure. The FHCW specimen achieved a maximum roof drift of 0.02 rad, while FTCBs attained a chord rotation up to 0.045 rad, demonstrating excellent ductility and considerable safety redundancy. An elastic coupling ratio of 67% was measured, indicating reliable FTCB‐to‐wall‐pier connections and efficient coupling action. The results confirm that the FHCW system offers a promising alternative for the design of resilient building structures.