Numerical studies on the entire debonding propagation process of FRP strips externally bonded to the concrete substrate

Debonding of FRP strips from concrete substrate is an important issue in FRP-strengthened concrete structures. While a great number of expressions have been published to determine the strength of the FRP-concrete bond, few closed-form solutions are available to well predict the entire load-displacement responses. This paper has numerically studied the full-range behavior of FRP strips debonding from concrete substrate by using Finite Element (FE) predictions which show good correlation with experimental results. Based on the numerical predictions, solutions have been developed to describe the load-displacement responses at each loading stage. The impacts of the strip width, the bond length, the thickness and the elastic modulus of FRP strips on the proposed solutions have been discussed. The proposed solutions show good accordance with the experimental results and the numerical predictions, indicating its reliability in predicting the interfacial behavior of FRP-concrete bond.