Investigation on the building structural damages of the Kathmandu nine-story Basantapur Tower in 2015 Nepal M8.1 Gorkha earthquake

摘要

The nine-story Basantapur Tower and its auxiliary buildings, which include the Lohan Chowk courtyard and its four tower groups surmounted at each corner, i.e., Kirtipur Tower (NW), Bhaktapur Tower (NE), Basantapur Tower (SW, namely the nine-story tower), and Lalitpur Tower (SE), located at the Durbar Square in the Kathmandu Valley in Nepal, is a world-famous UNESCO World Heritage Site. The towers are structurally correlated and architecturally inseparable. In the 2015 Nepal M8.1 Gorkha earthquake, these buildings were severely damaged, even locally collapsed. The authors were fortunately invited to have the chance to carry out a thorough field reconnaissance about the damages and on-site micro-vibration tests about the characteristic natural frequencies of these damaged buildings. The major observations about the structural damages of the tower buildings due to the earthquake are presented. In addition, the preliminary nonlinear finite element analyses are also carried out to find the reasonable way to numerically simulate the earthquake damages of these brick-timber building structures simultaneously. Comparison results between real and numerical damages of the nine-story Basantapur tower buildings are given.