Strengthening of masonry vaulted structures using FRP overlays

This paper aims to define the collapse mechanism of masonry barrel vault strenghtening with Fiber Reinforced Plastic (FRP) overlays, in the case of horizontal displacements of the abutments. To show the strenghtening effect in the model, tests were first carried out on the unreinforced masonry barrel vault. The tests were stopped when the system became unstable. In the secon step the structure was repaired with FRP overlays and the test was repeated until the collapse. The position of the hinges in the barrel vaults after strenghtening is obviously different from that of the unreinforced ones; the ductility is also different. The alternate displacement, producing an alternate state of stress (compressive-tensile) in some points of the structure, may also subject the FRP bonded zones to compressive stress. The phenomenon may detach the fabric at some points and reduce considerably the load carrying capacity of the structure.