Seismic Resilience Improvement of Reinforced Concrete Building Using Fiber‐Reinforced Concrete Retrofitting

ABSTRACT Reinforced concrete (RC) buildings are common in seismic regions; however, their normal concrete cover (NCC) exhibits brittle behavior, making them vulnerable during earthquakes. While fiber‐reinforced concrete (FRC) has been widely adopted to enhance structural performance, its use as a replacement for NCC in retrofitting remains largely unexplored. Most existing retrofitting approaches—such as RC jacketing, steel bracing, base isolation, damping systems, and fiber‐reinforced polymers (FRPs)—improve strength and energy dissipation but often involve drawbacks including increased member dimensions, added dead load, high cost, fire susceptibility, and complex installation. In contrast, the potential of fiber‐reinforced concrete cover (FRCC) is still underexplored, particularly in India, where seismic codes (IS 1893:2016; IS 13920:2016) provide no specific guidance for its application. To address this gap, the present study investigates a six‐story RC building located in seismic zone V, where NCC is replaced with crimped steel fiber‐reinforced concrete (CSFRC) at 0.5% and 1.0% fiber volume fractions with aspect ratios of 55 and 82, while retaining the NC core. Nonlinear pushover and fragility analyses are performed to evaluate seismic performance in terms of displacement capacity, ductility, energy dissipation, hinge formation, fragility curves, resilience, and repair costs. Results show that incorporating CSF in the concrete matrix increases displacement capacity by up to 57%, global ductility (51%), and resilience (up to 4.83%), leading to a reduction in collapse damage (16%), functionality loss (up to 16.5%), and repair costs (14%). These findings validate FRCC retrofitting as an effective seismic resilience strategy, bridging a crucial gap in Indian seismic codes.