CHARACTERIZATION OF FUNDAMENTAL TIME PERIOD OF MASONRY RESIDENTIAL BUILDING BY AMBIENT VIBRATION TEST

Abstract

Earthquake is the natural phenomenon that is inevitable and cannot even be predicted and has potential for causing the great damage and loss of life and properties. Since Nepal lies within the Himalayan Mountain range, it has experiences numerous major and minor earthquakes. A major earthquake of magnitude 7.6 occurred in 2015 (Gorkha Earthquake). The earthquake followed by aftershocks had caused considerable damage in structures including some of the temples and historic buildings. Among them 80% were masonry structures. The objective of this study is to determine the fundamental time period of masonry buildings by ambient vibration test. The fundamental time period of a building is the most important and critical parameter in earthquake resistance design of structures influencing its seismic behavior and structural response. In this study, a dataset of 100 masonry buildings with varying heights, base dimensions was analyzed. These buildings represent most of the building in Changunarayan-9 area. The time domain data collected by Geophone were transferred to the Geopsy software for processing and converted to frequency domain data by Fast Fourier transform algorithm present in the software. Then, for each sample fundamental time period were evaluated for those frequencies which are then compared with code based time period. The result shows that for the different category, formulation for the fundamental time period may be different which may show better performance using individual formulation.