With large number of vulnerable houses, Nepal faces a huge extant risk from future earthquakes. While compliance to the national building codes is increasing for the new buildings, existing non-code compliant buildings pose a huge threat to the occupants. It has been difficult to promote retrofitting of residential buildings in major urban and urbanizing cities across Nepal. The reasons for this are multi-fold: i) massive volume of existing buildings; ii) requirement of proper physical structural assessment by experienced engineers to determine the safety of the structure or necessity of structural strengthening - retrofitting or demolishing; and iii) absence of practical guidelines and skilled manpower for implementing retrofitting solutions.
After the 2015 Gorkha earthquakes in Nepal, a large-scale building survey was conducted using digital hand-held tablets for more than 1 million buildings in the region hit by the quakes. The massive dataset contains geo-coded information of building characteristics such as typology, damage to structural elements and overall damage level. This data was primarily used to categorise damage to houses and identify the affected house-owners’ eligibility for the Government’s housing reconstruction grant.
With support from UNDP Asia Pacific Regional iData Initiative, UNDP Nepal utilized this massive dataset from the earthquake affected region, and prototyped a Vulnerability Scoring model that can be used to prioritise potentially vulnerable buildings for interventions to reduce their vulnerability. The outcome of the prototyping suggests that, with a good level of confidence, this model can be applied to different municipalities to assess vulnerability of existing housing stock to promote the interventions for risk reduction and mitigation1 focused on over 1.4 million mud-bonded houses which are the most vulnerable or the 1 million cement bonded houses. The study offers an innovative approach to addressing Nepal’s challenge through prioritizing of buildings for retrofitting.