F-RCM bundle as connection in multiple leaf masonry: Experimental investigation

The goal of this study was to assess the gain obtained by a strengthening procedure based on the use ofFRCM Fiber Reinforced Cementitious Matrix as connectors between the outer faces of the 3-leaves masonry panel. So, an experimental investigation was carried out on a multiple leaf masonry strengthened by inserting some transversal C-FRP joints through the thickness of a three leaves masonry wall with a very poor inner core. The latter was constituted by mortar and stone aggregate. All the connection joints were inserted by a constant distance along the height of the masonry wall. The joints consist of a bundle of unidirectional long fibers held by a special mesh and inserting in the thickness of the wall by means of a cementitious matrix. The advantages ofhaving replaced an epoxy resin with cementitious matrix are multiple and regard, on one hand an increase in the reinforcement capacity and on the other an improvement in terms of durability of the structural reinforcement in respect with the FRPs. To this aim, the investigation was carried out, firstly, on the original non-reinforced masonry, then on the reinforced model. All the specimens were subjected to eccentric loads to produce out-plane effects. The transversal joints connect the two external leaves forming a symmetrical system of two vertical elements connected by horizontal rods. The benefit is both in limiting buckling phenomena and in increasing the load-bearing capacity even in the presence of higher Young elastic modulus of the inner leaf. The proposed technique gives back an enhancement ofglobal resistance and a not explosive collapse mechanism if compared to the reference not-reinforced masonry specimen