Numerical simulation of the fatigue behaviour of FRP strips glued to a brittle substrate

This paper investigates the behaviour of FRP strips glued to concrete subjected to the cyclic loads often induced on structures by dynamic actions, such as the ones induced by traffic loads or earthquake events. The study moves from a theoretical model recently formulated by the Authors and capable to simulate the mechanical response of the aforementioned FRP-to-concrete joints. The model formulation, shortly summarised in this paper, is consistent with the general assumptions of fracture mechanics and closed-form expressions are obtained for determining the key fracture-related quantities. Then, a parametric analysis is carried out for investigating the influence of both the cyclic load protocol and the bond length on the resulting cyclic response of the system under consideration. The obtained results unveil that debonding failure under cyclic actions can be described by means of general conceptual tools derived by the theory of fatigue.