Evaluation of seismic response characteristics of buildings by ambient vibration test

点击翻译按钮获取中文摘要

The objective of the study is to evaluate seismic response characteristics of buildings by the ambient vibration test. A portable system is developed for the ambient vibration or microtremor measurement. The hardware of the system consists of portable sensors, a small amplifier, a PC-card of A/D converter and a mobile computer. The response characteristics of the system is proportional to ground velocity in the period range of 0.05 to 1 second. A 3-channel system whose weight is only 5 kg is developed for evaluation of site characteristics. For evaluation of building vibration characteristics a 12-channel system with weight of 12 kg is developed.The software of the system consists of a) the program for monitoring and data acquisition and (b) the program for spectral analyses and display of the results. The latter is developed wit.h C++ builder to be operated under the Windows OS.The time history data is easily displayed with arbitrary scale in order to select the section suitable for the analysis. The Fourier spectra and the spectral ratio are computed and displayed with arbitrary scale to understand the results in the field measurement.Using the system, microtremors of ground are measured in Yokohama and Manila, and the ambient vibration of the building is measured in Yokohama. It is confirmed that the system makes possible the very quick and efficient measurement. For example, it takes 10 minutes for the microtremor measurement and about 2 hours for the building ambient vibration test. Using the data measured the methodology for evaluation of the site characteristics is examined.