Diagonal shear behavior of historic walls strengthened with composite reinforced mortar (CRM)

Composite reinforced mortar (CRM) represents an innovative strengthening solution for existing masonry structures. CRM is comprised of a composite grid embedded within an inorganic matrix (mortar) and it is applied as externally bonded reinforcement of masonry members. The composite grid bears the tensile stresses whereas the inorganic matrix is responsible for the stress-transfer between the composite grid and the substrate. CRM showed promising results in improving the mechanical properties of different masonry members, such as walls and arches. However, a full understanding of the mechanical behavior of CRM strengthened masonry members is still missing, which hinders the formulation of reliable CRM design guidelines. In this paper, an experimental investigation of the in-plane behavior of masonry walls made by historical bricks and strengthened with a CRM comprised of a glass fiber composite grid embedded in a lime-based mortar is presented and discussed. The parameters studied are the wall dimension and type (double leaf with and without diatoni). Furthermore, the effect of steel anchors on the strengthened wall capacity is investigated. The results obtained are finally analyzed using simple analytical formulations.