Full-scale experimental evaluation of flexural strength and ductility of reinforced concrete beams strengthened with various FRP mechanisms

Abstract

Carbon fiber reinforced polymer (CFRP) is used for enhancing the structural performance of reinforced concrete (RC) beams. Due to the high resistance of FRP against corrosion and decay, as well as its low specific weight, it has good luck in strengthening the main structural members. Since the FRP system is mainly used for retrofitting than design, its implementation methods are important. In this research, four various implementation methods are evaluated and defined as CFRP sheet, CFRP laminate, Near-surface mounted (NSM method) and combination of NSM and laminate (Hybrid). Full scale tests were done by 1000 kN capacity hydraulic jack. Four points loading is considered and simple support is used. Validation analysis is done and compared with ACI instruction and reasonable results have been achieved. In the past works extensive research has been done on the retrofitting RC beams with FRP and more focused on the internal FRP bars and NSM method. Various external methods are used for strengthening and retrofitting of the RC beams and all tests were done on the real size and full-scale beams. This paper presents an experimental program on five RC beams. One beam is defined as control beam that constructed with typical material and other four beams are retrofitted with various external FPR methods. Findings from the present work shows that maximum flexural capacity achieved by hybrid method. Moreover, the main achievement of this research is that hybrid type led to increase in the ductility and hardening than control beam.