Out-of-plane behaviour of clay brick masonry walls retrofitted with flexible deep mounted CFRP strips and additional single-sided FRCM overlay

The deep mounting of CFRP strips to masonry using a flexible adhesive was developed as a minimally-invasive and cost-effective out-of-plane seismic retrofitting technique for unreinforced masonry (URM) buildings. Previous experiments on one-way spanning full-scale walls confirmed the significant added value for out-of-plane lateral resistance and displacement capacity for the Flexible Deep Mounted (FDM) CFRP strips retrofitted walls with respect to unreinforced masonry. This out-of-plane performance could be further enhanced by the addition of a single-sided Fabric Reinforced Cementitious Matrix (FRCM) overlay to FDM CFRP strips retrofitted walls. The purpose of the current experimental campaign was primarily to investigate the out-of-plane performance of one-way spanning walls retrofitted with both FDM CFRP strip and a single-sided FRCM overlay. The results of the experiments confirmed the significant added value for out-of-plane lateral resistance of walls with the proposed retrofit combination with respect to the URM and solely FDM CFRP retrofitted walls. A cross section analysis using non-linear and linear material models for the used components was proposed. The model provided an overestimation of the lateral moment capacity for walls that were solely retrofitted with FDM CFRP strips for high mid-span displacement. For walls that were additionally reinforced with a single-sided FRCM overlay, the model provided a good approximation of both the internal moment versus curvature and the lateral moment versus mid span displacement relationships.