Seismic performance of existing masonry buildings strengthened by applying GFRP fiber reinforced lime mortar on both faces of the walls

A comparison between the in-plane performances of an unreinforced and a reinforced masonry building is herein presented so to evidence, by means of numerical simulations, the effectiveness of a strengthening technique, based on the application of a GFRP (glass fiber reinforced polymer) fiber reinforced lime mortar coating, in the reduction of the seismic vulnerability of existing masonry buildings. An almost regular type of two storey building was considered as reference in the study. Three different types of masonry were concerned: solid bricks, rubble stones and cobblestones. The mechanical properties of the reinforced masonry were calibrated on the basis of numerous experimental tests carried out by the authors. Static nonlinear analyses of the structure were carried out using the equivalent frame model; the nonlinear behavior of the wall elements (piers and spandrels) was concentrated in plastic hinges arranged at the extremities of the member (flexural plastic hinges) or at mid-span (shear plastic hinge). The results evidence a significant increase in terms of shear resistance, displacement capacity and total strain energy. The collapse due to bending in the piers of strengthened buildings may in most cases anticipate the shear failure, limiting the displacement capacity of the structure.