Seismic Performance Evaluation and Retrofitting Strategies for Mid-Rise Reinforced Concrete Buildings

Abstract

Reinforced concrete (RC) framed buildings constitute a large share of themid-rise building stock in seismically active regions, yet a considerableproportion of this stock was designed and constructed before the enforcement of modern seismic codes. This paper evaluates the seismic performance of a representative ten-storey RC building and examines the effectiveness of selected retrofitting strategies in improving its response. A numerical model of the structure was analysed under code-compatible lateral demand, and the inter-storey drift, base shear, and fundamental period were extracted for the as-built configuration. Three retrofitting schemes, namely concrete jacketing of columns, addition of reinforced concrete shear walls, and introduction of concentric steel bracing, were then compared. The results indicate that bracing and shear-wall interventions reduce peak inter-storey drift substantially while keeping the increase in mass within acceptable limits. The study concludes that the choice of a retrofitting strategy should balance stiffness enhancement, ductility demand, foundation capacity, and constructability rather than relying on a single performance indicator. KEYWORDS: Seismic performance, Reinforced concrete, Retrofitting, Inter-storey drift, Steel bracing, Shear wall, Pushover analysis