STRENGTHENING OF MASONRY ARCHES: THE "SANTA MARIA DELLE GRAZIE" CHURCH

The "Santa Maria delle Grazie" church is a monumental masonry complex on the isle of Ischia. The monument is on a mountaintop near the panoramic road leading from the city centre to the mouth of the Arso crater. The structural restoration, still ongoing, involves every part of the building to improve the seismic response. The main intervents concern the reinforcement of the walls, the reconstruction of the timber roof, the slabs and the collapsed portions and the strengthening of the intrados of the vaults and arches with the FRCM system. Two of the four facades, the South and the Est, are buttressed by a system of arches. The south arcades appear more vulnerable since they insist on a slope. The arcades' reinforcement work involves applying a grid of PBO tapes in a cementitious matrix on the intrados. The purpose is to compensate for the lack of tensile strength of the masonry apparatus by counteracting the opening of plastic hinges. PBO (Polyparafenilenbenzobisoxazole) is a synthetic fibre used in structural reinforcement systems with a cementitious matrix. Compared to the most commonly used composite materials, it possesses remarkable mechanical characteristics and has high chemical compatibility with inorganic compounds. It is often used for reinforcing masonry buildings thanks to the high compatibility of the matrix with which it is applied to the masonry support. The purpose of this research is to develop a simplified modelling strategy for FRCM-reinforced curved masonry structures able to use by technicians with a sufficiently accurate description of the mechanical behaviour of arches reinforced with FRCM composites.