Performance of un-reinforced burned clay brick masonry walls retrofitted with locally available materials

In Sri Lanka, there is a large number of unreinforced masonry buildings and they have possessed a deep-seated view in local culture since ancient time. Un-reinforced masonry is the most vulnerable against earthquakes, which highlights the need of introducing proper techniques for retrofitting of existing un-reinforced masonry buildings. The objective of this study is to evaluate the possibility of selected techniques (external poly propylene band mesh, ferrocement belts and the proposed external bamboo strip mesh) to increase seismic safety of existing masonry structures. Masonry walls having the size of 600 mm × 600 mm × 215 mm were cast using bricks. The masonry walls with and without retrofitting were tested under static diagonal compression test. The effectiveness of retrofitting techniques was evaluated using initial cracking load, ultimate load carrying capacity, crack initiation and propagation, residual strength and failure mode, shear stress and wall stiffness. Test results indicated that retrofitting of un-reinforced masonry walls with bamboo strip mesh and poly propylene band mesh could be effective and reliable strengthening techniques. These methods are also economical and simple in technique. The wall retrofitted with ferrocement belts collapsed without catastrophic failure. Withal, this technique was capable of dissipating some energy and redistributing the load, and showed considerable visible signs before the collapse. The ferrocement belts method might be reliable for retrofitting of un-reinforced masonry buildings.