Experimental assessment of shear response of brick masonry retrofitted with TRM

Abstract

As one of the main historical construction materials, masonry is abundant among the architectural heritage of earthquake-prone areas of the Mediterranean countries. Earthquake mitigation approaches are now focusing on strengthening solutions based on compatible and environmentally friendly repair materials. These solutions should efficiently improve the in-plane lateral strength and displacement capacity, which are the two most significant parameters considered in the seismic assessment of masonry buildings. This paper reports an experimental programme on masonry walls composed of handmade solid clay brick and hydraulic lime mortar, a recurrent typology for historical buildings. Tests under cyclic in-plane forces were carried out on unreinforced and retrofitted walls. The unreinforced walls were repaired and retrofitted after being damaged in the first test and were then tested again to investigate the recovery of strength. The repair consisted in filling the open cracks and replacing the damaged bricks by following the so-called “scuci-cuci” technique. The retrofitting consisted of externally bonded textile reinforced mortar (TRM). The investigated TRM system was a continuous bidirectional grid of basalt embedded in hydraulic lime mortar. The experimental results show the suitability of the proposed solutions for seismic retrofit and post-earthquake repair of existing masonry buildings. The research results highlight the effectiveness of the investigated systems in increasing the resistance and ductility of unreinforced brick masonry. In addition, the results allow a better understanding of the behaviour of masonry walls subjected to cyclic horizontal displacement.