Analytical models for shear–displacement curves of unreinforced and FRP reinforced masonry panels

Starting from the 1980s, several computational techniques for the solution of the masonry response problem have been proposed, but due to the intrinsic complexity of real structures, they are of little significance for practical design purposes. Moreover, the linear elastic solution is not correct in the hypotheses, and very often grossly in error on the shear response curve. The static non-linear push over method has been established in the Italian design rules in 1976, shortly after the great Friuli earthquake. The initial procedure has been revised and integrated over the years, and appears to be a very sound design tool for short, well organised, regular masonry structures. One of the drawbacks of the method is the hypothesis of bilinear shear response curves of single unreinforced and reinforced panels. This type of approximation is severely in error with respect to experimental results, although the ultimate strength is well captured. In the paper this approximation is removed by introducing an analytical response curve obtained by satisfying the axis wise equilibrium conditions while assuming a no tension, elastic–plastic in compression relationship for masonry.