SEISMIC ANALYSIS OF PAGODA STYLE BRICK MASONRY TEMPLE

Abstract

Nepal is one of the long-identified high seismic hazard nations lies in the central most segment of the Himalayan collided zone. During its history, Nepal has experienced six large/great damaging earthquakes (1255, 1408, 1505, 1833, 1934, and 2015) with magnitudes equal to or greater than 7.6 and several strong earthquakes since 1255 (Thapa et al. 2017) and have caused serious disasters with huge human casualties and countless monetary losses. Old temples built in Nepal have their own archeological and historic importance so its conservation has been major national and international concerns. Seismic analysis of such structure has become very important for safeguarding the structure from the future earthquake. Among the old temples the pagoda style temple has been reserved for religious and spiritual activities. Pagoda style temples show different dynamic behavior than other traditional unreinforced masonry (URM). Understanding seismic vulnerability and structural behavior of theses pagoda style temples can lead to more efficient retrofit solution and conservation practices for similar heritages. Yakshyeshwor temple is a type of pagoda style brick masonry temple which is one of the oldest temple in Bhaktapur. Seismic analysis of the temple has been performed. For the analysis equivalent static and response spectrum analysis has been performed. From the equivalent static method maximum floor displacement, interstory drift ration and stress induced in the model has been determined. The maximum displacement found to be 59.348mm at the upper floor of the structure. Modal analysis has been performed to determine the natural frequencies mode shape of the structure. The time period in the structure found to be 0.404s. For the response spectrum analysis elastic response spectra of medium soil sites from Is code has been used. The maximum floor displacement due to response spectrum analysis is 141.27mm. From both method the stress induced in the structure has exceeded the permissible stress, thus the retrofitting is needed to maintain its strength.