Comparative study of the simulation ground motion by amplitude scale and spectral matching

Abstract

Dynamic analysis is more accurate than static analysis in determining a response of structure due to earthquake loads. The limitation of this analysis is the lack of recorded ground motion data of an earthquake for the entire territory of Indonesia. Therefore, according to the Indonesian Code, it is permitted to use seismic data from other locations that have similar seismic characteristics. In application, ground motions need to be modified to match the Indonesia design code. There are two modification methods, which are amplitude scaling and spectral matching. Thus, the purpose of this study is to determine the reliability of these two methods. As the result, the response spectra of the ground motion modified by the spectral matching method present a similar pattern to the target response spectra compared to the amplitude scaling method. Ground motions modified by the spectral matching method generate Peak Ground Acceleration (PGA) values almost the same as the target PGA values. In contrast, the modified motions with amplitude scaling provide diverse PGA values that are not the same as the target PGA. From this study, the utilization of the spectral matching method is recommended in modifying ground motion data for dynamic analysis.