An analytical model to predict bond behavior of fiber reinforced polymer bonded to concrete with an end anchorage system

The end mechanical anchorage system has been widely applied in the conventional externally bonded reinforcement (EBR) technology, to hinder the premature debonding failure of fiber reinforced polymer (FRP) laminate, especially for the reinforcement structures with prestressed FRP due to higher interfacial shear stress at the ends. Through the introduction of the hinge as the substitution of end anchorage, this paper presents a numerical model based on the bilinear bond-slip model and ordinary differential equations in elastic, elastic-softening, and elastic-softening-debonding stages. The bond behavior of the FRP-concrete interface under the end anchorage in different stages is predicted, obtaining the analytical expressions of interfacial load-slip relation, interfacial shear stress distribution, and the stress distributions of FRP. Additionally, two experimental programs from this group and previous literature were involved in this study to validate the accuracy of the numerical model. The comparison shows they are in good agreement. Moreover, it indicated that the strength increase is linear with the torque applied in the end anchorage, but bonding strength is not the case.