Following the 25 April 2015 Mw 7.8 Gorkha, Nepal, earthquake and subsequent aftershocks, field surveys were conducted on medium-to-high rise reinforced concrete (RC) frame buildings with masonry infill located in the Kathmandu Valley. Rapid visual assessment, ambient vibration testing, and ground-based lidar (GBL) showed that these buildings suffered damage ranging from light to severe, where damage occurred in both structural and nonstructural elements, but was most prevalent in nonstructural masonry infills. Finite-element structural analyses of selected buildings corroborate field observations of only modest structural damage. The lack of severe structural damage in this relatively limited class of engineered medium-to-high rise RC infill frame buildings illustrates the impact of modern seismic design standards and stands in stark contrast to the severe damage and collapse observed in low-rise nonengineered RC infill frame buildings. Nonetheless, the nonstructural damage hindered many of these buildings from being occupied for many months following the earthquake and subsequent aftershocks.

This paper presents a novel methodology to combine ambient vibration-based operation modal analysis with three-dimensional ground-based lidar data to study damage on the Nyatapola Temple, which is a Bhaktapur UNESCO World Heritage Site that was damaged during the 2015 Gorkha, Nepal, earthquake. The post-earthquake ambient vibration data, collected via accelerometers placed on various levels of the temple, are used to estimate the vibrational properties via operational modal analysis. These properties are then compared to the pre-earthquake dynamic characteristics collected in 2002. The lidar data provide a geometric assessment of the current condition of the temple, capturing post-earthquake drift as a function of height as well as significant cracks present in the facade. The lidar data also inform the numerical models implemented for the post-earthquake condition assessment of the temple.

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The collapse of unreinforced masonry structures, which are widely distributed around the earthquake prone regions of the world, is one of the greatest causes of death in major earthquake disasters. This paper presents an innovative retrofitting method for masonry structures, which uses bamboo band arranged in a mesh fashion and embedded in a mortar overlay. In order to evaluate the effectiveness of the proposed retrofitting technique, shake table tests were conducted using retrofitted and non-retrofitted 1/4 scaled masonry houses with sinusoidal ground motion inputs. Based on the experimental results, the retrofitted specimen exhibited good seismic performance withstanding over twice larger input energy than what non-retrofitted specimen could do.