A theoretical model for intermediate debonding of RC beams strengthened in bending by FRP

In the present paper, a mechanical model accounting for the interface stress-slip relationship is presented with the aim of simulating the behavior of RC beams strengthened by externally bonded FRP systems. Finite element implementation and validation of such a model will be outlined with the aim of pointing out the capability of the proposed procedure of reproducing both end and intermediate debonding phenomena which often affect the overall behavior of FRP-strengthened beams. Behavioral observations will be pointed out for emphasizing the role of the key parameters controlling premature (fracture energy, steel yielding strain, reinforcement amount, etc.) failure due to intermediate debonding.