The infilled RC structures performance in the 25th April, 2015 Gorkha Nepal earthquake: Observations and dynamic characterization tests

On the 25th April, 2015 in the region of Gorkha (Nepal), a 7.8 Mw magnitude destructive earthquake caused tremendous damages and losses in the entire country. Following the earthquake a team from the University of Porto, in collaboration with other international institutions visited some of the more affected areas and concluded that the infill masonry walls had an important contribute in the structural response of the reinforced concrete (RC) structures. It was observed that in some cases the infills protect the RC structure and in others the infills introduced global mechanisms that caused severe damages or even the structural collapse of innumerous buildings. Factors associated with the existence of soft-storeys at the ground-floor, poor geometric configurations, design and construction practices and other reasons were found to be critical in the buildings response. A characterization of the RC buildings typology in Nepal will be performed as well as a report of the main structural and non-structural damages observed in this structures after this event is presented along the manuscript. Secondly, it shows results from data collected on ambient vibration tests performed in infill panels with the same characteristics but different levels of damage.