Seismic performance of RC coupled shear wall structure with hysteretic-viscous replaceable coupling beams: Experimental and numerical investigations

Conventional reinforced concrete coupling beams in shear wall structures are expected to dissipate most of the earthquake input energy through plastic deformations in regions (plastic hinges), resulting in costly repairs or construction demolition. In order to prompt resilient societies, this study presents a new type of replaceable coupling beam (RCB) equipped with hybrid energy dissipation devices and investigates experimentally and numerically a reinforced concrete (RC) shear wall (SW) structure with innovative RCBs. The new hybrid device combines viscous and metallic dampers in parallel within a single device, enhancing performance across a wide range of seismic intensities. The metallic device is expected to yield under the design earthquake, providing the main structure with sufficient lateral stiffness and a reliable, large source of energy dissipation capacity, while under wind or low-intensity earthquakes, only the viscous damper works provide supplemental damping to the structure. To evaluate the seismic performance of the coupled shear wall structure with the proposed RCB, cyclic loading tests were conducted first on the viscous damper. Subsequently, bidirectional shaking table tests were performed on a 1/4 scaled, seven-story coupled SW structure with twenty-eight new hybrid energy dissipation devices, considering different seismic intensities. A conventional RC coupled SW was also tested for comparison. The test results demonstrate that the proposed hybrid device significantly outperforms conventional systems by (1) reducing interstory drifts and story acceleration demands under a wide range of seismic intensities and (2) concentrating damage within the hybrid device while minimizing damage to other components, thereby expediting the repair of buildings subjected to extreme seismic events. Furthermore, 3D finite element models for the shaking table test specimens were established in OpenSees and validated against experimental response. Successively, a numerical parametric study was conducted by performing nonlinear response history analyses under a set of 22 ground motions to investigate the influence of different shear force distributions of the hybrid device on the peak interstory drifts and peak story accelerations. The seismic performances of the coupled SW structure with RCB equipped with hybrid devices were evaluated and compared to that of the structure utilizing metallic devices.