Cyclic in-plane shear behaviour of unreinforced masonry wall panels strengthened with NSM FRP strips

An experimental study was conducted to assess the effect on strength, displacement capacity and ductility of reinforcing unreinforced masonry (URM) shear panels with near surface mounted (NSM) fibre reinforced polymer (FRP) strips. A total of eight wall panels (2 URM and 6 reinforced) were subjected to vertical pre-compression combined with increasing reversing cycles of in-plane lateral displacement. All of the wall panels had dimensions of 1200mm x 1200mm x 110mm (height x length x thickness). Three different FRP reinforcement schemes were used (two repeat specimens for each scheme). The study revealed that the FRP strengthening was effective in improving the ultimate load resisted by the wall panels (increases of up to 9%), the displacement capacity (133%) and ductility (108%) compared to the URM response. The reinforcing scheme which used a combination of vertical and horizontal FRP strips performed the best overall in terms of improving both the ultimate in-plane shear load resisted by the wall panels and the displacement capacity. The broader aim of the research is to identify techniques for improving the seismic performance of existing URM walls under in-plane shear loading