Analytical model for the in-plane shear behavior of URM walls retrofitted with FRP

This paper presents an analytical model for in-plane shear behavior of unreinforced masonry (URM) walls retrofitted using fiber reinforced polymers (URM-FRP). The proposed model idealizes masonry, epoxy, and FRP in a URM-FRP as different layers with isotropic homogenous elastic materials. Then, using principles from the theory of elasticity, the governing differential equation of the system is formulated. A double Fourier sine series is used as a solution for the differential equations. A simple computer program was developed to combine the solution of the differential equations with material nonlinearity. The material nonlinearity was represented by step-by-step layer stiffness degradation; after each step the equations are resolved linearly. The proposed basic analytical model allows the fundamental investigation of in-plane shear behavior of URM-FRP. Finally, effects of epoxy and masonry ductility as well as allowable shear stresses and FRP axial rigidity on the shear strength of URM-FRP are examined. In addition, comparisons with three existing models are carried out.