Predominant Frequency Shift of Low-Rise Buildings During Earthquakes Using One Accelerometer by Nonstationary Amplitude Spectrum

Abstract

For decision on safe evacuation and continued use of buildings, structural health monitoring systems with several sensors have been developed for mid- and hi-rise buildings. In this paper, a simple monitoring method for low-rise buildings is introduced using only one sensor at the top of the building. In the method, predominant frequency of building and its shift during an earthquake is extracted using nonstationary amplitude spectrum applying multi filter technique to analysis of severe earthquakes. Based on the seismic observation records of a heavily damaged low-rise RC building during the 1994 Sanriku Haruka-oki Earthquake, the effectiveness of this method was demonstrated by comparing with the natural frequency evaluated by the ARX model from the records of two or more sensors. In addition, based on an analysis of observed records of a mid-rise SRC building damaged in a major earthquake, the characteristics of the proposed method were examined by comparing it with the characteristics of a low-rise building.