An analytical study for debonding in single-lap shear test by considering the residual strength

External bonding of composite reinforcements has become an accepted method for strengthening the existing structures, e.g., FRCM to concrete. In the present manuscript, the shear lag model is combined with two different bond-slip laws to investigate the mechanics of debonding of composite-to-substrate joints by considering the residual strength. Boundary conditions of the problem are written based on a so-called pull-push test, while the obtained equations can also be used for the pullout test. Results illustrate the considerable effect of friction in mode II debonding, even at starting the process. Despite the simplicity of equations and differences in bond-slip laws, it is demonstrated that both the models predict the debonding load with reasonable accuracy. Finally, some simple expressions - generalizing the ones without residual friction - are proposed to calculate the effective bond length.