Rubble stone masonry retrofitted with FRCM and injection of mortar

Assessing the seismic vulnerability of historical masonry structures is essential for preserving cultural heritage but is often challenging due to numerous uncertainties. Structural retrofitting is typically required, as most ancient masonry cannot withstand modern seismic standards. However, there needs to be more data and guidelines for designing effective retrofitting solutions tailored to these heritage buildings. To address this gap, an experimental campaign was conducted at the Structures and Strength of Materials Laboratory (LERM) of the Instituto Superior Técnico (IST), University of Lisbon. The primary objective of this campaign was to gain a deeper understanding of the in-plane structural behaviour of stone masonry walls, representative of historical masonry structures that have been strengthened with composite materials. Specifically, the study focused on rubble stone masonry retrofitted using the Fabric Reinforced Cementitious Matrix (FRCM) system and/or mortar injection techniques. The experimental programme included (i) the characterization of materials used for the construction and strengthening of the specimens and (ii) quasi-static cyclic shear compression tests. Various combinations of strengthening solutions, including mortar injection and the application of the FRCM system, were implemented to evaluate their effectiveness in improving the seismic resilience of these historical structures. Key parameters, such as the deformation and shear resistance capacity of the masonry, were examined to assess how these strengthening methods enhance the seismic performance of masonry structures. This understanding is essential for designing effective retrofitting strategies for historical unreinforced masonry (URM) structures.