COMPARATIVE STUDY ON SEISMIC PERFORMANCE OF RC FRAME WITH CONCENTRIC STEEL BRACING

Abstract

Designing multistorey buildings with sufficient lateral stability in seismic-prone areas is crucial to withstand earthquake forces and control lateral drift. Steel bracing systems within reinforced concrete frames provide an effective solution. They offer advantages such as ease of erection, space efficiency, and design flexibility to meet required strength and stiffness levels. Implementing steel bracing systems enhances the seismic performance of multistorey buildings, improving their ability to resist lateral forces and minimize lateral drift. To achieve this, 4, 8, and 12-storey dual RC-MRCBFs are designed with commonly employed chevron, X, and 2-storey X bracing configurations. The present study focuses on the comparative behaviour of RC frames with different concentric-brace configurations. The nonlinear static and dynamic analysis has been performed in order to access the seismic performance of the multi-storey buildings with three distinct types of steel bracings. It was observed that installation of bracing into the RC frame system increase the strength and stiffness of the frame significantly. It also reduces the inter-story drift ratio and floor accelerations of the buildings. Among all configurations, 2-storey X steel bracings have shown improved strength, stiffness, and ductility behaviour. The effect of placement of 2-storey X bracings has also been examined in the study, and an enhanced behaviour of 2-storey X bracing placed in alternative bays was observed than the 2-storey X bracings provided in the same bays. The results of the study can be utilized in order to retrofit the RC frames with different type of bracing configurations based on the requirement and constraints.