Comparative study of seismic performance between fixed base and base-isolated regular RC frames (G+21 floors) using SAP 2000

Abstract

The study investigates the seismic performance of fixed base and base-isolated regular reinforced concrete (RC) frames (G+21 floors) using SAP 2000. High-rise buildings in seismic zones require innovative design approaches to mitigate earthquake-induced damages. Base isolation is a promising technique that decouples the structure from ground motions, potentially reducing seismic forces and enhancing performance. This research focuses on comparative analysis through detailed modeling and simulations. Two structural models—fixed base and base-isolated—are developed in SAP 2000. The base-isolated model incorporates elastomeric bearings to absorb seismic energy. The study evaluates seismic response parameters, including story displacements, base shear forces, inter-story drift ratios, and natural frequencies. Results indicate significant improvements in the seismic performance of the base-isolated structure compared to the fixed base. Maximum lateral displacements and inter-story drift ratios are considerably lower in the base-isolated model, demonstrating enhanced stability and reduced damage potential. Base shear forces are also substantially reduced, highlighting the effectiveness of base isolation in dissipating seismic energy. The natural frequency analysis shows a shift to lower values for the base-isolated structure, confirming the increased flexibility and energy absorption capacity. The findings underscore the potential of base isolation to improve seismic resilience in high-rise buildings, providing valuable insights for engineers and designers in seismic-prone regions. Future research should explore various isolation materials and configurations to optimize performance further.