Study on earthquake intensities for seismic analysis of structures

Assessing the elastoplastic performance of seismic structures is now playing a more and more important role in performance based seismic design.Nevertheless,it is difficult to use an appropriate earthquake intensity index for variant ground motions.Since the influence of different factors of ground motions upon elastoplastic performance of seismic structures is quite sophisticated,it is significantly important to choose a rational earthquake intensity index,which could give the comprehensive reflection of the variant characteristics of ground motions and the seismic responses of structures.Herein,the existing 33 earthquake intensity indices in the literatures are reviewed and summarized.The correlation between these earthquake intensity indices and the seismic response of structures is studied for elastoplastic SDOF and MDOF systems,and the applicability and characteristics of these earthquake intensity indices are also discussed.Based on the correlation analysis,a suggestion for selecting earthquake intensities is presented.