Performance Assessment of Existing Retrofitted Reinforced Concrete Buildings With Different Steel Bracing Systems

Abstract

Steel bracing systems are efficient schemes for retrofitting existing seismically vulnerable multistoried buildings. Many reinforced concrete (RC) buildings worldwide are being retrofitted using different types of steel bracing systems. However, it is essential to determine the most efficient type of bracing system applied to existing practical multistoried buildings that will yield better performance during an earthquake incident. This study intends to compare the seismic performance of different steel bracing systems applied in three seismically inadequate existing RC building frames by exploring the inelastic responses of the buildings. Nonlinear static pushover analysis is carried out to assess the structural performance of the bracing systems. Different steel bracing systems, such as inverted V-bracing, X-bracing, ZX bracing, and Zipper bracing systems, are used. The performances in terms of strength, inelastic story displacement capacity, plastic-hinge formation, and interstory drift variation are investigated. Considering the performance and the economy, it is observed that the ZX bracing system is the most efficient bracing system for the buildings studied.