Effect of Seismic Design Provisions of Indian Standards on Seismic Response of URM Infilled RC Step-Back Building on Hill

Indian Himalayan region spans across 10 different administrative states in the country and constitutes a significant portion of the Indian subcontinent. An ever-increasing population and scarcity of flat lands for construction in the hilly region forces construction of buildings on the sloping terrain with foundations constructed at different levels. These buildings are inherently vulnerable to earthquakes due to the horizontal and vertical irregularities that are extremely hard to avoid because of the nature of the terrain. Compounding on that fact, a large population of buildings in the region have been constructed without following the design provisions of earthquake resistant design and ductile detailing in IS 1893 [5] and IS 13920 [6] respectively. Consequences of such design and construction practices have shown to have devastating consequences in recent earthquakes such as the 2011 Sikkim earthquake and 2015 Nepal earthquake. The paper aims to assess the combined effect of seismic design provisions of Indian Standards on the seismic response of a set of Un-Reinforced Masonry (URM) infilled RC Step-Back building on hill. A 3D analytical model with interaction of frame and infill actions has been taken into account by diagonal strut elements alongside the frame elements. Nonlinear analyses have been performed for realistic assessment of key parameters influencing seismic performance of such buildings.