Comparison of macroseismic-intensity scales by considering empirical observations of structural seismic damage

In practice, seismic intensity is evaluated in accordance with a macroseismic-intensity scale recognized in the field of seismic engineering globally. The application of different seismic-intensity scales to evaluate the seismic damage of a specific structure due to an earthquake yields diverse results. On this basis, this study compared a few extensively used macroseismic-intensity scales. The results can be used as a reference to develop an international intensity scale. According to empirical structural-damage survey data from the Wenchuan earthquake (Mw = 8.0) that occurred on 12 May 2008 in China, the European Macroseismic Scale (EMS)-98, Medvedev, Sponheuer, and Karnik (MSK)-81, and Chinese Seismic Intensity Scale (CSIS)-08 intensity scales were utilized to evaluate the resulting damage. This study carried out a vulnerability analysis of typical structures, established vulnerability seismic-damage matrices, and mapped out vulnerability curves under different intensities. Our objective is to demonstrate that the use of multiple intensity scales can lead to very different intensity levels. The differences in the damage of typical structures under different intensity levels were obtained from an evaluation using the three aforementioned intensity scales. As a result, a calculation model of the mean damage index is proposed herein. Ultimately, this article conducted an analysis on the failure characteristics of typical structures in an earthquake and provided effective measures to improve seismic performance for future reference.