Seismic Analysis of High-Rise Building Using Different Base Isolators

Abstract

Base isolation is a proven technique that decouples the superstructure from ground motion, thereby enhancing seismic resilience by increasing the fundamental time period and dissipating energy through isolator deformationThis study presents a comparative seismic analysis of a high-rise reinforced concrete (RC) building using different base isolators: Lead Rubber Bearings (LRB) and High Damping Rubber Bearings (HDRB) to evaluate their effectiveness in reducing seismic responses.. In this research, a G+10 storey RC building located in Seismic Zone III with medium soil conditions was modelled and analyzed using SAP2000 software as per IS 1893: 2016 (Part 1). Two analytical models—fixed-base and base-isolated were developed and subjected to nonlinear time history analysis using the Kobe (1995) and Superstition Hills (1987) earthquake records. The study analyzed key seismic parameters such as storey displacement, inter-storey drift, and base shear. Results indicated that both LRB and HDRB systems significantly reduced seismic demands compared to the fixed-base structure. The findings demonstrate that base isolation effectively enhances structural performance under seismic excitation. LRB provided greater flexibility and energy dissipation due to the yielding of its lead core, whereas HDRB offered higher inherent damping and temperature stability. The choice between the two systems depends on design priorities, cost, and environmental considerations. Overall, this study confirms the efficiency of seismic base isolation in improving the safety and sustainability of high-rise buildings in moderate seismic zones.