Design of the out-of-plane strengthening of masonry walls with fabric reinforced cementitious matrix composites

Abstract

Fabric reinforced cementitious matrix (FRCM) composites, made of high strength textiles externally bonded with inorganic matrices, experimentally proved effective to enhance the capacity of masonry walls. With the aim of fostering the transfer of knowledge from scientific research to engineering practice, this paper proposes an approach for the design of the out-of-plane flexural strengthening of masonry walls by FRCM systems. The mechanical properties of the reinforcement are derived by combining the results of tensile tests on textile specimens and FRCM-to-substrate shear bond tests. An expression for the preliminary design of the reinforcement is proposed, according to a limit analysis approach, based on tensile and bond strength of FRCM. Whereas, for structural assessment, strain compatibility is enforced, and the bending moment capacity of the reinforced wall is based on FRCM stiffness, tensile and bond strains, consistently with existing building codes. An estimate of the out-of-plane displacement capacity is also developed, which is particularly useful in seismic assessment. A wide experimental database is used to validate theoretical relationships, tune calibration coefficients and derive safety factors, in accordance with the design-by-testing framework of Eurocode 0 for ultimate limit state design.