Experimental seismic testing of semi-reinforced stone masonry buildings in mud mortar

Abstract

The 2015 Gorkha earthquakes and associated aftershocks damaged or destroyed more than 30,000 school classrooms in Nepal. For future proofing, the Government of Nepal is constructing earthquake resilient school buildings using cement and steel in the areas accessible by motorable roads. However, transporting such construction materials to many of the inaccessible earthquake-affected areas is logistically challenging and financially nonviable, with stone and mud being the only construction materials that are readily available in such inaccessible areas. Three multi-hazard resilient stone masonry school building typologies were developed that utilise abundantly available local materials. The conceptual design of these low strength masonry buildings is reported herein. Preliminary results are presented from an extensive experimental campaign that included shake table tests. Three prototype modular school buildings were designed with loadbearing walls composed of stone masonry in mud mortar and provided with light metal roof. The walls of the buildings incorporated horizontal bands and surface containment steel mesh on both surfaces of the walls. The containment mesh was tied with wires passing through the walls. Each prototype was constructed at 1/3rd and 2/3rd scale and was subjected to multiple base excitations with increasing amplitude up to 1.0g. The damage ranged from cracking to global/local sliding and rocking along the multiple bedding planes of the walls. The model buildings survived the intense shaking without triggering any unstable modes of failure, thereby confirming compliance of the proposed designs to applicable Nepal seismic standards.