Evaluating the Role of CFRP, AFRP and GFRP in Seismic Retrofitting of RC Buildings: a Performance-Based Approach

In performance-based seismic design, accurately assessing structural behaviour and associated risks requires accounting for uncertainties in material properties, loading, and site conditions. This study evaluates the enhancement of the seismic performance of Reinforced Concrete (RC) buildings through the application of Fiber Reinforced Polymers (FRP), including Carbon (CFRP), Glass (GFRP), and Aramid (AFRP), with confinement thicknesses ranging from 0.1 mm to 0.5 mm. The influence of FRP thickness on structural capacity, inter-story drift, and overall resilience of a seven-story RC building is investigated using nonlinear pushover analysis in conjunction with probabilistic risk assessment. The results identify the minimum effective thickness at which each type of FRP begins to significantly improve seismic performance. CFRP exhibits the highest gains, achieving strength increases of up to 7.52% and ultimate displacement enhancements of 12.68% at a thickness of 0.5 mm. AFRP and GFRP also enhance performance, though to a lesser extent. Probabilistic analysis further confirms a reduced likelihood of seismic damage, particularly in states of slight and moderate damage. Based on structural performance metrics and reliability considerations, CFRP is determined to be the technically optimal material and thickness for seismic retrofitting. These findings provide practical guidance for the effective application of FRP confinement to enhance the resilience and safety of reinforced concrete buildings under earthquake loading.