Experimental shear behaviour of masonry walls reinforced with FRCM

The shear strength of piers and spandrels is a crucial factor in masonry buildings, affecting structural safety. Such a strength can be increased in several ways, particularly by using fiber reinforced cementitious matrix (FRCM) reinforcements. These reinforcements can be applied symmetrically on both sides of the wall or only on one side. As it is well known, the FRCM-to-substrate adhesive properties strongly affect the effectiveness of such reinforcements. Moreover, a complete covering of the reinforced surface with bidirectional mesh evenly distributes the stresses, improving the load-bearing capacity. Appropriate test methods, for example diagonal tests, can be effectively used to evaluate the shear capacity of masonry panels, even with externally bonded composite material reinforcements, and the corresponding failure mechanism. This paper describes the results of an experimental campaign involving masonry panels, made with three different types of mortar, also reinforced with a PBO-FRCM system, subjected to diagonal tests. Through the experimental results, it was possible to determine the shear capacity of the panels, identify the failure mechanisms and evaluate the effectiveness of the FRCM reinforcements. The predictive capability of design formulas proposed in the literature for evaluating the shear capacity of unreinforced and reinforced masonry panels has been analyzed in the paper.