Flexural behaviour of reinforced concrete beams repaired using a hybrid scheme with stainless steel rebars and CFRP sheets

Abstract

The repair of corroded reinforced concrete (RC) structures is a critical issue for structural designers and managers because the repair cost significantly dominates the life-cycle cost. Moreover, in chloride-containing environments (e.g. coastal environments), RC structures repaired with conventional methods may corrode again since the ingress of chloride ions, water, and oxygen into the concrete will not be completely restrained. In this paper, a novel repair method for corroded RC beams using stainless steel (SS) rebars and externally bonded carbon-fibre-reinforced polymer (CFRP) sheets is proposed. The flexural behaviour of a group of RC beams repaired using the proposed method is experimentally investigated. The test variables include the longitudinal reinforcement types (i.e. carbon and SS), shear reinforcement configurations, and CFRP sheet wrapping schemes. Experimental results demonstrate that a carbon steel (CS) reinforcement can be replaced with an SS reinforcement to reduce future repair costs since there is no significant difference in the flexural behaviour of beams reinforced with CS and SS rebars. The effectiveness of CFRP sheet wrapping schemes on the flexural performances of SS-RC beams is approximately identical to that of CS-RC beams. In addition, the present paper discusses the serviceability and ultimate limit states of RC beams retrofitted with SS rebars and CFRP sheets based on the current design codes for ordinary RC beams strengthened using CFRP sheets. The predictions are in good agreement with the experimental results.