Experimental, numerical and field study investigating a heritage structure collapse after the 2015 Gorkha earthquake

Abstract

This paper presents an investigation of the collapse of a 325-year-old multi-tiered heritage temple during the 2015 Gorkha earthquake in Kathmandu, Nepal. The research comprises a reconnaissance survey followed by a geotechnical investigation and numerical back-analysis carried out to understand the potential causes of the collapse. The assessment of the structural configuration of the temple indicated seismic vulnerability in the design due to the presence of discontinuous columns over the height of the temple and age-weakened bonding in the masonry walls. The geotechnical investigation revealed the presence of competent soil strata at the location, assisting the survey which indicated no differential or excessive settlement in the foundation. A series of cyclic triaxial tests were conducted on samples recovered during the geotechnical investigation to determine dynamic behaviour of the soil. Further, dynamic analysis of the plinth of the temple under the recorded acceleration-time history indicated a maximum drift percentage of 1.4% and residual relative displacement of 32 mm suggesting the potential reason behind the collapse. The output of this research will support seismic rehabilitation of ancient structures within World Heritage sites across Nepal and effective action plans to safeguard them against future earthquake hazard.

Evaluating the Seismic Performance of Domestic and Historical Masonry Structures in Himachal Pradesh Region of India

“…Kumar et al (2019) reported the damaged pattern of heritage structures within World heritage sites of Kathmandu during 2015 Gorkha Earthquake and stated the age-related deterioration and out-of-plane collapse of masonry wall were the main reason. Kumar et al (2020) studied the collapse of Jaisidewal temple (historical Pagoda style architecture) in Nepal during the 2015 Gorkha earthquake. The study showed that the seismic vulnerability in a 325-years-old temple arose due to deteriorating masonry wall and presence of discontinuous columns in the temple, while there was no failure in substructure i.e.…”

“…It was also noted during post-survey 2015 Gorkha earthquake that some of the masonry structures which survived the1934 Great Nepal Bihar earthquake and the 2011 Sikkim-Nepal earthquake, collapsed during the 2015 Gorkha earthquake having similar structural features, lack of proper maintenance (Kumar et al 2019(Kumar et al & 2020.…”