NUMERICAL SIMULATION OF THE CYCLIC RESPONSE OF FRP STRIPS GLUED TO CONCRETE

CAGGIANO A.,; E. MARTINELLI

Conferencia; AIMETA 2017; 2017

This paper aims at investigating the cyclic response of FRP strips glued to concrete subjected low-cycle fatigue actions, such as those induced by earthquake events. The study starts from a theoretical model capable to simulate the mechanical response of the aforemen-tioned FRP-to-concrete joints. The model is formulated within the general theoretical frame-work of fracture mechanics under the assumption that debonding occurs as a pure mode II cracking process throughout a zero-thickness interface between the FRP strip and the con-crete substrate. Under the conceptual standpoint, the model proceeds as an incremental anal-ysis and the debonding phenomenon is simulated as a propagating fracture whose local residual stress is described by the decreasing branch of the bond-slip law. Isotropic softening behavior is assumed in the local response of the interface under cyclic loads. A further exten-sion of the interface model is also proposed for taking into account rate-dependent effects by following a classical overstress viscoplastic approach available in the literature. The me-chanical response of FRP strips glued to concrete and subjected to cyclic actions is firstly in-vestigated by considering different values of the relevant structural parameters and various cyclic loading protocols characterized by average force levels and load amplitudes. Then, the numerical examples consider the visco-plastic behavior of fiber-reinforced polymer sheets glued on concrete substrates under different strain rates by comparing experimental data against the proposed numerical simulations.