EXPERIMENTAL INVESTIGATION OF LOW COST STEEL WIRE MESH RETROFIT FOR STONE MASONRY IN MUD MORTAR

Stone Masonry in Mud Mortar is a widely used typology for construction of buildings for any use including schools in the Hill and Mountain range of the Himalayan region. It is the only local construction material abundant in this region. A major land portion of Nepal lies in the high mountains and rolling hills that accounts for about 83% of the total land area. Due to the economic advantage it offers and the difficulty in transporting external materials through the challenging Himalayan terrain, the stone in mud mortar has been the material of choice in rural schools for decades. In the 2015 Gorkha Earthquake, 60% of stone masonry schools were damaged. With little research done on these structures, countries like Nepal are in dire need for in depth study on the behavior and lateral load capacity of this typology. Most importantly,
it is crucial to study the retrofitting measures that can be implemented to make these structures more resilient to earthquakes. Under the Seismic Safety and Resilience of Schools in Nepal (SAFER) project, which is a consortium of
several organizations lead by University of Bristol with funding support from Global Challenges Research Fund (GCRF) and the Engineering and Physical Sciences Research Council (EPSRC), a series of full scale wall tests were conducted in Kathmandu on stone masonry walls. Due to the high variability in terms of the stones used and construction practices, a large number was designed to permit statistical processing of the results using locally available materials such as
galvanized steel wire mesh for wall retrofit. Monotonic lateral tests were performed to study the effects of retrofit on the load vs displacement behavior. It was observed that after retrofit, the failure pattern changed to more distributed cracks instead of a large localized one. The results also showed that, despite the low cost of the intervention, a significant enhancement was achieved on both lateral capacity (324%) and deformability (131%) of the stone in mud masonry walls. The overall experimental campaign highlighted a practical method for setting up a low cost test in a developing country context, thus paving the way for increasing the number of the available experimental results in regions where such data are scarce.