Experimental and numerical response of CFRP-strengthened concrete beams with low or medium steel corrosion

Abstract

The present study deals with the validation of a numerical model that can approximate the flexural behavior of corroded reinforced concrete beams patch repaired and strengthened with carbon fiber reinforced polymer (CFRP). Six reinforced concrete beams were corroded under an accelerated corrosion technique to low and medium corrosion levels respectively. Two beams were used as control, while the remaining four were patch repaired and strengthened with externally bonded reinforcement (EBR) and near surface mounted reinforcement (NSM) with equivalent axial rigidity. After repairing the concrete substrate and subsequent bonding of the CFRP reinforcement, the beams were tested to failure under four-point loading. The developed 3D finite element models take into account the different mechanical properties and detailing of corroded bars and of the mortar patch as well as of the existing concrete - mortar patch interface and of the NSM or EBR FRP - mortar patch interface. The FE analyses may reproduce the observed modes of failure including crushing of the concrete after steel yielding and debonding of CFRP. The analytical load-deflection curves compare well with the experimental flexural behavior of the corroded RC beams patch repaired and strengthened with EBR and NSM CFRP laminates.