Out-of-Plane Behaviour of Tuff and Brick Masonry Walls Strengthened with FRCM Composite Materials

Strengthening with composite materials is becoming more and more an effective solution for increasing the structural safety of masonry buildings, often subjected to severe degradation or potentially vulnerable to seismic events. Structural retrofitting can be performed according to different techniques, based on Fiber Reinforced Polymer (FRP) or Fiber Reinforced Cementitious Matrix (FRCM) strengthening systems. The second group of composite systems is usually preferred nowadays thanks to some important advantages such as better compatibility with the substrate, applicability on wet surfaces, fire resistance, permeability and reversibility. Several experimental and numerical studies can be found in literature concerning masonry panels strengthened with FRP and FRCM systems. The knowledge about the use of the latter, nevertheless, is still partially limited, in particular if the out-of-plane behaviour of walls is taken into account, with the experimental and numerical database available resulting mainly restricted to monotonic cases. In this framework, results of an experimental campaign devoted to the study of the out-of-plane behaviour of tuff and brick masonry walls strengthened with different types of FRCM systems will be presented and discussed in this paper, performing also a comparison with available predictive formulas. Experimental results showed, in general, good performance of FRCM composite materials, with a proper exploitation of their tensile capacity, proving their effectiveness for the out-of-plane strengthening of historical masonry walls.