Out-of-plane maximum resisting bending moment of masonry walls strengthened with FRCM composites

Fiber reinforced composites represent an alternative to more traditional techniques for strengthening and retrofitting existing masonry structures. Numerous studies have been carried out to characterize the mechanical and bond behavior of Fiber Reinforced Cementitious Matrix (FRCM) composites applied to different substrates and to provide reliable parameters for the estimation of the FRCM composite contribution to the strengthened member. However, limited work was done to provide reliable design procedures for FRCM strengthened structures and the only available guideline is the American ACI 549.4R-13. In this paper, a new analytical procedure to estimate the out-of-plane maximum resisting bending moment of FRCM strengthened masonry walls is provided. The accuracy of the proposed procedure is assessed by comparison of the analytical provisions with corresponding experimental results from a database comprising 63 FRCM strengthened walls collected from the literature. The results obtained are compared with those computed according to the ACI 549.4R-13 approach and to a method based on the procedure by Ascione et al. (2015). The new procedure proposed provides accurate results, whereas the ACI 549.4R-13 approach and the method based on the procedure by Ascione et al. (2015) generally tend to underestimate the experimental maximum resisting bending moment providing a low accuracy.