Modeling of single-flexural crack induced debonding of FRP plate strengthened concrete beams based on an assumption of heterogeneity

Abstract External bonding of fiber reinforced polymer (FRP) plate has become a popular method for strengthening concrete structures in recent years. This paper presents a numerical study of single-flexural crack induced debonding based on a progressive damage model. The ongoing debonding process is simulated. Interfacial stress distributions for different load levels are analyzed. A parametric study, including influence of heterogeneity of the adhesive layer, size of the flexural crack, thickness of the adhesive layer and the FRP plate and elastic modulus of the adhesive layer on the critical load is carried out. The numerical results indicate that the interface shear stress decreases gradually from the pre-existing crack or the debonding tip to the FRP plate ends along the FRP-concrete interface. Although local debondings nucleate at random locations, the dominated debonding initially starts from the pre-existing crack and propagates to the FRP plate ends as the load increasing.