Research on composite strengthening of historical housebuilding: Retrofitting intervention for masonry arches and vaults

A Seismic retrofitting of structures belonging to the architectural heritage requires meeting of constraints which are related to preservation of artistic features. Such a philosophy was applied to the design process of the retrofitting intervention of a masonry arch, belonging to a 17th century portico built inside a Roman amphitheatre in the city of Spoleto (Italy), and of two masonry vaults of an ancient building in the city of Foligno (Italy). This led to the opportunity of investigating the efficiency of an innovative composite material, based on fine steel cords embedded in a cementitious matrix (Steel Reinforced Grout). To assure an adequate strength against earthquake, a couple of prestressed SRG strips, in the first case, and a reticular system, made of transversal and longitudinal prestressed SRG laminates, in the second case, have been applied on the extrados of the arch and of the vaults, respectively.