Field investigation on the performance of building structures during the April 25, 2015, Gorkha earthquake in Nepal

On April 25, 2015, a major earthquake of moment magnitude M-w 7.8 struck the Gorkha District of Nepal at 11:56 a.m. local time (6:11 a.m. UTC). One major aftershock of M-w 7.3 on May 12, 2015, contributed to the devastation of many villages in mountainous areas nearby the epicenter. The spatial distribution of aftershocks, which extended 150 km to the east of the epicenter, suggests that the rupture propagated from west to east, thus producing severe destruction in Kathmandu, at approximately 80 km southeast of the epicenter. A total of 800,000 buildings were severely damaged or collapsed. A post-earthquake reconnaissance showed that damages in reinforced concrete buildings in urban areas were mostly due to poor construction quality, low concrete strength, non-seismic detailing in beam-column joints, and local site effects. Most of the masonry buildings in the villages nearby main shock epicenter were also affected. This paper presents the recorded accelerograms, acceleration response spectra, and the seismological aspects of the earthquake. Case histories of damaged buildings, the patterns, and the failure mechanisms are discussed in this paper. It is concluded that a majority of the damaged buildings were not designed or constructed properly in accordance with national building codes of Nepal or ACI codes. (C) 2016 Elsevier Ltd. All rights reserved.