Systems of arches and columns strengthened with FRP at the extrados

The topical problem of the maintenance and upgrading of the masonry building heritage has led, in these last years, to an increasing interest in new and suitable material and technologies. As a consequence the application of composite material, also on masonry structures, is nowadays considered an assessed and quite usual practice. Nevertheless the adoption of new techniques requires a deep knowledge of the behavior of the reinforced structure and a definition of adequate models able to simulate it. Aim of this paper is the evaluation of the structural behavior of a system of arch and columns, strengthened with FRP at the extrados and loaded by a vertical force at the crown and by two horizontal forces at the abutments of the arch. The scope is pursued by means of a proposed methodology, which, with some simplifying assumptions, allows defining the failure interaction locus of the strengthened structure. The effectiveness of the strengthening intervention is evaluated on the basis of these strength domains defined in the plane of loads.