Abstract:To investigate the impact of different fiber reinforced polymer (FRP)-concrete interface bond-slip models on the shear performance of FRP-strengthened reinforced concrete beams, this study designed and cast five rectangular reinforced concrete beams. Four of these beams were reinforced with carbon fiber reinforced plastic (CFRP) using four different methods: side strip spaced reinforcement, continuous strip reinforcement, U-shaped spaced reinforcement, and U-shaped continuous reinforcement. Field tests were conducted on the reinforced concrete beams. By utilizing Abaqus finite element analysis software, a finite element analysis model based on the interface debonding failure process was constructed by selecting three existing bond-slip models. The analysis results were subsequently compared with the experimental findings. The results indicate that the finite element simulations correlate well with the experimental observations regarding the failure process and ultimate load capacity of the reinforced beams. There is an increase in shear capacity ranging from 13.5% to 42.9%, while the finite element simulations demonstrate an increase between 5.5% and 47.7%. The shear and slip variation curves before and after debonding reveal that the FRP-concrete interface debonding occurs instantaneously. Following interface damage, the shear carried by the CFRP strips transfers to adjacent strips, further inducing interface damage that leads to strip delamination. Ultimately, the failure mode of the CFRP-reinforced concrete beams is characterized by progressive CFRP delamination, resulting in insufficient ultimate load capacity of the beams. Different bond-slip relationships result in variations in interface damage development, which subsequently influences the FRP strip delamination process and ultimately affects the overall FRP shear contribution. For identical reinforcement configurations, simulation results with varying bond-slip relationships indicate errors in CFRP shear contributions ranging from 0.1% to 15.9%. Among these, the Nakaba model demonstrates a more conservative CFRP shear contribution, while the Lu model generally provides the most accurate simulation results.