Behaviour of soft brick masonry small assemblies with and without strengthening under compression loading

A large percentage of the building stock in India and around the world comprises of non-engineered unreinforced masonry (URM) structures. The performance of these buildings in the past has shown that they are highly vulnerable to failure under seismic loads. Very few studies in the past have focused on behaviour of URM structures made of bricks with low strength and stiffness. Hence, the main objective of this study is to improve the understanding of brick masonry made of low strength and low stiffness bricks and assess the effectiveness of various strengthening schemes namely glass fiber reinforced polymer (GFRP) composites and textile reinforced mortar (TRM) systems. The scope of the study includes the following: (i) experimentally characterising the mechanical properties including stress strain curves for bricks, mortar and prisms cast with various mortar composition under pure compression and (ii) to experimentally assess the performance of masonry assemblies such as prisms and triplets strengthened with GFRP and TRM composites. TRM strengthening involves external application of poly-propylene (PP) grid as reinforcement using cement mortar layers as a matrix. GFRP strengthening is found to increase the strength, stiffness and deformational capacity of masonry prisms made with all grades of mortar. TRM strengthening using PP grid increased the strength, stiffness and deformational capacity of prisms made of low strength mortar but resulted in premature failure in prisms made of high mortar strength. In case of shear triplets, both the GFRP and TRM strengthening increased the strength and stiffness.