Modelling of the bond behaviour of curved masonry specimens strengthened by CFRP with anchor spikes

Aim of the present paper is the proposal of a simple modeling approach for the numerical simulation of the bond behavior of masonry specimens externally strengthened by FRP strips equipped with anchor spikes. The model is based on a simple 1D-schematization of specimens, previously proposed by the authors and based on the use of linear and nonlinear spring elements schematizing the support, the FRP, the masonry/FRP interface. The approach here proposed specifically considers the coupled behavior between shear and normal stresses arising at the masonry/FRP interface level and, moreover, it introduces constitutive laws for modeling local failure mechanisms involving the anchor. The parameter setting procedure presented in the paper is indeed devoted to implicitly consider the contribution of the anchor and its interaction with the masonry support, directly at the FRP/masonry interface level. This allows to reduce computational efforts while preserving a good reliability level of the model. The validation of the proposed modeling approach is here carried out by considering experimental tests performed by the authors and available in the current literature. The results obtained from the numerical analyses reported in the paper show both the reliability of the proposed approach to capture the experimental behavior and, moreover, its efficacy for investigating the role of the anchor on the bond behavior of the strengthening system.