STRUCTURAL SUITABILITY OF MASONRY STRUCTURE FOR RESIDENTIAL BUILDINGS IN RURAL AREAS OF NEPAL

Abstract

Construction of masonry structures using different kinds of masonry units is still widely in practice in the rural area and suburban part of Nepal. For the suitability of the building and its implementation evaluation of seismic performance is required. Its affordability and use of local material in construction also govern the suitability of structures in a different locations. For this four typologies of the building based on reconstruction in 32 districts after the Gorkha earthquake was considered for the analysis. These four buildings are of different mechanical properties and wall thickness but all of them have common usable space. These buildings were modelled using finite element software and analysis by using linear dynamic analysis. In this study, the damage is idealized as the maximum top storey displacement of each building. Three-time histories (Gorkha, Imp Valley and Kobe) were used for the linear dynamic analysis. Base shear, displacement and drift of different buildings using different PGA of an earthquake were determined. By using the First-order second moment method probability of failure of each building were determined and a fragility curve was generated. These fragility curves were compared to understand the seismic performance characteristic of the selected structural system. Material and labor required for the building were estimated using standard norms of Nepal. The total cost of the selected building system was calculated using rate of Rammechhap district. The result shows that the Lateral displacement and storey drifts are considerably reduced while the contribution of brick wall with cement mortar (BCEM) is taken into account. The probability of failure of a different building is a smaller percentage in the analysis of houses applying the Gorkha Earthquake than the other two earthquakes (Imp Valley and Kobe) earthquake. Also, the cost of SMUD typology is found to be lowest and use of local material in SMUD typology is highest among four typologies.