Strengthening of Masonry Vaults with Textile Reinforced Mortars

Masonry vaults are dramatically vulnerable against non-symmetric loads, relative support displacements and earthquakes. In numerous existing structures, retrofitting is needed to improve the safety level and, for this purpose, externally bonded composites are particularly useful and have already been installed in the field. This paper describes an experimental investigation performed to gain an improved knowledge on the response of masonry vaults reinforced with Textile Reinforced Mortar (TRM) composites. Three full-scale vault specimens, provided with backfill and buttresses, were subjected to cyclic loading at 1/3 span. Displacements were measured with the help of Digital Image Correlation, which also provided information on damage pattern and arch-fill interaction. TRM was installed either to the extrados or to the intrados and proved effective to prevent or delay the onset of the four-hinge mechanism, which was replaced by crushing of the masonry. Stress and damage concentrations were avoided; the strength was increased by 2–3 times and the deflection capacity by up to ten times.