VULNERABILITY ASSESSMENT OF MASONRY BUILDING

Abstract

Nepal is in a seismically active zone with a high potential of massive earthquake. Globally, Nepal ranks 11th in term of its relative vulnerability to earthquake. The collapse of unreinforced masonry structures is one of the causes of death in earthquake disasters. Due to improper methods, lack of knowledge for the construction and maintenance a large number of unreinforced masonry building was collapsed during Gorkha earthquake. Gorkha earthquake appears to have been stronger than the 1934 earthquake, possibly making it the largest earthquake recorded in Nepal in almost a century. The observations of the damage pattern indicate that the majority of the damaged buildings were stone or brick masonry structures with no seismic detailing. Hence the need for evaluating the seismic adequacy of the existing masonry building has come into focus. In this research, seismic vulnerability of masonry buildings constructed in Tarkeshwor Municipality has been carried out. Three load bearing masonry buildings were selected for modeling in ETABS V22.0.0 Various methods of rapid visual screening (FEMA 154, EMS 98) are used to determine the vulnerability of the selected building. The Selected Building response is carried out by linear time history analysis. The seismic vulnerability of masonry structures is determined in terms of fragility curves which represent the probability of failure or damage due to various levels of strong ground motions for different damage state slight, moderate, extensive and collapse. From the result of RVS and Fragility curves of the buildings it is found that all three buildings are vulnerable from future earthquakes.