A study on long period portion of design spectra
ZHOU Yong-nian,ZHOU Zheng-hua,YU Hai-ying (Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China)
The accelerograms of some large earthquakes recorded by digital accelerographs are used for analyzing the features of long period component of strong ground motion. The mean acceleration response spectra and their fitting spectra for different sites are derived. The characteristic periods and the spectral values for long period portion of the design spectra in the code for seismic design of buildings (GB50011-2001) of China are obviously lower than those from the statistical results. A suggestion on modifying the design spectra is made and an experimental relation of spectral values with different damping ratios is proposed.