Exploring the Efficacy of Base Isolation System in Mitigating Seismic Forces for Irregular Structures

Abstract

Irregular reinforced concrete (RC) structures present unique challenges in seismic design, often requiring innovative  solutions to ensure adequate protection against earthquake forces. This study examines base isolators, focusing on  their critical role in reducing seismic forces by decoupling structures from ground movement during earthquakes. The  project aims to assess the application of base isolation systems (BIS) in irregular structures and their impact on seismic performance. The literature review covers the evolution of structural engineering in RC buildings. The modelling phase  utilises ETABS to create three models for base-isolated and fixed-base structures. Seismic analysis through the response spectrum method in ETABS provides insights into the dynamic behaviour of these structures. The comparative analysis reveals a significant increase in time periods for base-isolated structures across all models, indicating enhanced seismic performance. The circular frequencies further support the effectiveness of base isolation in reducing stiffness and  improving overall seismic resilience. Furthermore, the study focuses on maximum storey displacement in both X and  Y directions, highlighting the superior performance of base-isolated structures in restricting lateral movement during  seismic events. The reduction in maximum storey drift values reinforces the effectiveness of the base isolation system in mitigating seismic forces, offering improved structural stability and reduced deformations. Hence, the consistently superior performance of base-isolated structures compared to fixed-base counterparts, as evidenced by increased time periods, lower circular frequencies, and reduced maximum storey drift values, supports the viability of base isolation as a seismic retrofitting solution for irregular structures.