Experimental and numerical analysis of the behaviour of masonry walls strengthened with CFRP reinforced render

Old masonry walls, which present a limited bending capacity, generally need strengthening in order to provide an overall seismic resistance to old buildings. To achieve such purpose an innovative strengthening technique was developed, consisting in the application of an exterior render layer with a structural role. The flexural resistance improvement of such technique results from the mechanical properties of the materials used and requires a proper application procedure. This innovative solution, henceforth designated as “CFRP reinforced render”, consists of a lime base mortar reinforced with a carbon mesh, applied on one or both faces of the masonry wall. The reinforced render solution, developed within this study, aims to provide improved mechanical capabilities to the strengthened masonry walls while respecting the main principles for rehabilitation of ancient buildings. In particular, it complies with material authenticity/compatibility principle, because it is based on a lime base mortar, and with the structural compatibility principle, as it involves a distributed strengthening all over the main original structural elements—the masonry walls, instead of imposing unbalanced concentrated strength. In this context, an extensive experimental campaign was developed involving in-plane and out-of-plane full-scale bending tests on plain and on strengthened wall specimens reproducing the mechanical and geometrical characteristics of old masonry walls. Based on the experimental results obtained, a numerical approach was developed to simulate the behaviour of the plain and of the strengthened masonry walls for different geometrical configurations and for different mechanical parameters. Besides allowing a better understanding of the behaviour of the strengthening technique, the developed models presented in this paper may aid the design of CFRP reinforced render solutions.