Seismic retrofitting of low strength unreinforced masonry non-engineered school buildings

Abstract

Schools in Nepal, both their buildings and its occupants face extreme risk from earthquakes because of highly vulnerable building stock and high occupancy in it. Further, schools house an entire generation and a community's future so these need special attention. Loss suffered by a community in collapse of a school is psychologically much greater than any other community building. In 1988 the Udaypur earthquake, which measured 6.6 on the Richter scale, about 950 school buildings incurred damage of different degrees spanning between damage to collapse. A study completed by the Kathmandu Valley Earthquake Risk Management Project in 2000 AD, to explore the seismic vulnerability of school buildings and possible intervention options in Kathmandu Valley, showed a grim situation. This paper explores the methods that were implemented for strengthening existing low strength unreinforced masonry school buildings. A basic emphasis was placed on economic affordability, technical implementation and its adoptability by local craftsmen. The retrofitting design was based on identification of deficiencies, the most critical failure mechanisms, and simple calculations.