A New Design-Oriented Formula for Masonry Shear Wall Strengthened with Composite Reinforced Mortar

The use of inorganic matrices in structural engineering field has increased considerably thanks to novel retrofitting systems which focus on the best symbiotic action between fiber-based mesh embedded into mortar (lime- or cement-based). The possible combinations of the constituents are so many, but a clear distinction can be made concerning the type of reinforcement: fiber mesh or FRP-grid. In the first case, a Fabric Reinforced Cementitious Matrix/Mortar (FRCM) is obtained; the latter is a Composite Reinforced Mortar (CRM). One of the most adopted applications is the shear strengthening of masonry walls. In fact, FRCM/CRM provides its own additional in-plane strength and, at the same time, improves the original capacity of the wall itself. This double-action behavior is demonstrated in numerous experimental tests evidencing the influence of fabrics and mortars when combined to several masonry typologies. It must be highlighted that state-of-knowledge is currently more consolidated for FRCM systems, for which Design-Oriented Models (DOMs) have been calibrated with respect to large databases. Conversely, further research efforts are needed referring to CRM-systems. With this aim, the present paper reports on the updated data availability concerning the shear strengthening of masonry walls with CRMs (as part of a larger study). The goal is to propose a new empirical formula for design purposes using the best fit method, while minimum scatter between the experimental and theoretical outcomes.