Empirical Correlations of Generalized Intensity Measures of Horizontal-Vertical Ground Motions in China

How to reasonably consider the effects of vertical ground motion has become a key scientific issue in the current seismic field of engineering structures. In this paper, based on the ground motion records in the Chinese region, several Chinese ground motion models (GMMs) of horizontal and vertical generalized intensity measures (IM) are established. Then the empirical correlations between horizontal-vertical IMs are analyzed, and the nonparametric bootstrap method and Fisher z-transform are used to consider the uncertainty of the correlation coefficients. The empirical correlation coefficients of the horizontal-vertical IMs are modeled to be applicable to the Chinese region. The results show that the GMMs developed in this study for the Chinese region are practical. There is a medium-high correlation mainly shown by the horizontal-vertical homogeneous IMs. The values of the correlation coefficients between horizontal-vertical spectrum-, effective peak-, amplitude-IMs and spectral acceleration (Sa(T)) mainly depend on the defined period. The correlation coefficients of cumulative effect IMs and Sa(T) show a decreasing tendency with the increase of the period. The correlations between duration IMs and Sa(T) show weak negative correlation or no correlation. The correlation coefficients obtained in this study based on the horizontal-vertical Chinese ground motion records are basically consistent with the trends in existing studies. The correlation coefficient prediction models established in this study are well fitted. The results of correlation studies and the GMMs established in this paper can be easily applied to seismic engineering analyses in China.