Seismic Response of Base-Isolated Buildings With High Damping Rubber Bearings Having Different Design Characteristics

Abstract

In this study, the use of high damping rubber bearing (HDRB) with various design properties in mitigating the seismic effects for steel buildings was investigated. For this, a generalized demand on the analytical model of HDRB was introduced and eighteen different models of HDRB were examined comparatively. These models were created by considering three significant isolation parameters of HDRB such as isolation period T (2, 2.5, and 3 s), effective damping ratio βeff (0.05, 0.10, 0.15), and post-yield stiffness ratio λ (3 and 6). The benchmark low (3-storey), mid (6-storey), and high-rise (9-storey) steel buildings were equipped with different isolation systems of HDRB and then subjected to a set of earthquake ground motions through nonlinear time history analyses in order to evaluate the actual nonlinear behaviour of the bearings in the base-isolated steel buildings in service. The base-isolated frames were assessed by the variation of the selected structural response parameters such as isolator displacement, relative displacement, inter-storey drift ratio, absolute acceleration, base shear, base moment, hysteretic curve, and dissipated energy. The effectiveness of the steel buildings with HDRB was evaluated. It was shown that the seismic performance of the base-isolated structure was remarkably influenced by the isolation parameters. The higher value of the isolation period and effective damping ratio tended to increase the amount of dissipated energy associated with low post-yield stiffness ratio.