Mechanical model based on a BVP for FRPs applied on flat and curved masonry pillars with anchor spikes

The use of fiber reinforced polymer (FRP) materials for strengthening interventions of existing constructions is a consolidated and widespread technique. In this context, although strengthening interventions generally involve curved masonry elements (arches, vaults, domes, etc.), only a few studies specifically concern the influence of the geometry curvature, or the effect of mechanical anchors (widely used in current practice for preventing premature failures), on the bond behavior of FRPs. The present paper proposes an interface exponential model for simulating the bond behavior of curved masonry pillars reinforced with FRP strips applied at the intrados or extrados by both epoxy adhesive and anchor spikes. The proposed model is based on a relatively simple boundary value problem (BVP) obtained by assuming for the spike a constitutive behavior under shear forces quantitatively deduced by post-processing the numerical data from a finite element micro-modeling approach previously proposed by the authors. The application of the proposed model to experimental cases carried out by the authors underlines the stability of solution and the reliability of the proposed approach to account for the effect of both the curvature of the substrate and the presence of the spike anchor on the bond behavior of FRPs.