Ambient Vibration Measurements in Representative Buildings in Kathmandu Valley Following the Gorkha Earthquake

Abstract

The horizontal-to-vertical spectral ratio is a widely used technique to identify fundamental frequency and amplification by both structural and geotechnical engineers. Following the 215 Gorkha earthquake, ambient vibration measurement was conducted in central Kathmandu Valley considering representative building types. Well-designed high-rise reinforced concrete (RC), residential RC (poorly designed), brick masonry (cement mortar), medium-rise RC, and medium-rise precode RC buildings were chosen for ambient vibration measurement. As the first attempt to estimate the natural frequencies of buildings in Kathmandu Valley, ambient vibration records were taken at various heights of the buildings. Another aim of this study was to identify the possibility of vibration resonance in the existing building types; thus, free-field measurements were also taken during the building measurements.