Seismic performance enhancement of shear wall structures using lead viscoelastic coupling beam

Abstract

Replaceable coupling beams (RCBs) have gained great attentions in enhancing seismic performances of coupled shear wall (CSW) structures, showing superior advantages over the conventional reinforced concrete (RC) coupling beams. Recently, the authors proposed using the lead viscoelastic damper as a replaceable fuse to fabricate a new RCB, i.e., the lead viscoelastic coupling beam (LVCB). The hysteretic behaviors of this fuse were experimentally and numerically investigated, but the performance of using LVCB in controlling the seismic response of CSW structure has not been studied yet. This paper therefore studies the seismic enhancement of CSW structure with LVCB. Finite element models of CSWs with LVCB or RC coupling beam are developed and their hysteretic behaviors, energy dissipating capacities and damage modes are investigated by considering different floor configurations. Nonlinear time history analyses are also performed to evaluate the seismic responses of the LVCB enhanced CSW structure. Results show that applying the LVCB to the CSW makes the deformations concentrate in the damper, providing a favorable hysteretic performance with an equivalent damping ratio of about 0.35. The isolated floor reduces about 20 % of the initial stiffness of the CSW structure, but has insignificant effect on the loading capacity, which can improve the damper's deformability and reduce damages of RC components. The seismic response analyses also demonstrate the effectiveness of the LVCB for structural response mitigation, giving the average reduction ratios on story drift, shear force and bending moment are 8.28 %, 11.49 % and 8.22 %, respectively. It is believed that the LVCB is a reliable and practical RCB, showing a wide application prospect in engineering practices.