A Detailed Study on the Mud-Bonded Masonry Houses in Nepal Both Before and After 2015 Gorkha Earthquake

Being a developing country with the majority of ruralRural settlements followed by historic settlements, NepalNepal has a large percentage of old and new unreinforced mud-bonded masonry (URMM) houses. Along with this fact, NepalNepal has a bitter reality of lying in a highly earthquakeEarthquakes-prone region, which has led to huge structural damages (especially URMM houses) in each earthquakeEarthquakes (including the recent 2015 GorkhaGorkha earthquakeEarthquakes). This reveals the poor construction technique adopted in NepalNepal and shows the immediate need to make suitable improvements in the structural characteristics of URMM houses. However, the immediate introduction and implementation of new methodology and technologyTechnology for sustainable improvement of structural characteristics might not be fruitful/effective until and unless the ways of the past are well understood. Hence, analysing the past and current ongoing construction technologyTechnology is always necessary for future intervention to any structure. So, with an intention to present the entire common construction techniques (both good and bad) of mud-bonded masonry (MM) houses and contribute to its further improvement, a detailed reconnaissance survey (includes inspection of nearly 36,000 old and new MM houses), active group discussions and questionnaires with engineers, local people and masons were carried out in different geographical regions of NepalNepal for nearly 9 years (since early 2012). It was observed that the majority of the old houses (constructed before the 2015 earthquakeEarthquakes) were lacking seismic consideration and had a huge variation in local construction techniques (influenced by the availability of building materials, housing purpose, economic condition, locality construction practices, climatic condition, caste system, etc.). But after the 2015 GorkhaGorkha earthquakeEarthquakes, such variations were drastically reduced, and comparatively, there was an improvement in construction practices. The overall obtained findings (present and past status of MM houses, good and bad/deficiencies construction techniques, common structural elements, etc.) are expressed through the data and further verified using good quality pictures as evidence which has been the highlighting part of this paper and contributed to developing a clear concept for all the readers. This paper also presents the recommendationRecommendation based on the management of old MM houses and improvements to be done in construction practices. (The author wants to thank his family, colleagues and the entire technical staff of NRA, DLPIU, Okhaldhunga, for their support and encouragement during the overall detailed investigating phases).