Effect of multiple secondary cracks on FRP debonding from the substrate of reinforced concrete beams

For a FRP strengthened concrete beam, debonding is often initiated by the opening of a flexural or shear/ flexural crack along the concrete beam. This debonding failure is often studied with the pull-off test. However, experimental results indicate that debonding on a concrete beam occurs at a significantly higher force than that in the pull-off tests, which can be ascribed to the presence of multiple cracks along the beam span. In the present investigation, an analytical model that accounts for the opening of shear/ flexural cracks along the beam is developed. The proposed analytical model has also been verified with the experimental results.