Basic concepts of seismic zonation in Russia are the degree of intensity and soil categories that correspond to discrete structure in the ratio “seismic impact-ground reaction”. Meanwhile, the parameters of seismic ...Basic concepts of seismic zonation in Russia are the degree of intensity and soil categories that correspond to discrete structure in the ratio “seismic impact-ground reaction”. Meanwhile, the parameters of seismic effects, and the parameters of soil properties are continuous in the space. The report expounds the basic theory, adequately representing the above mentioned continuality. Thus, many the concepts of seismic zonation, used now, become either more correct, or unnecessary.展开更多
In this study we examined the applicability of the NEHRP soil classification which is based on the VS,30 parameter and the corresponding Fa and Fv factors to correct acceleration response spectra for local site classi...In this study we examined the applicability of the NEHRP soil classification which is based on the VS,30 parameter and the corresponding Fa and Fv factors to correct acceleration response spectra for local site classification. We calculated acceleration response spectra (10% in 50 years) for more than 1900 sites across Israel. Computations were made for hard rock conditions and for the actual site conditions, while considering nonlinear response of the soils. Based on synthetic acceleration response spectra of real sites (using stochastic procedures), it is concluded that generalizing site classification and consequently, amplification, by means of a single parameter VS, 30 is not recommended. The geology of Israel is complex and may vary significantly over short distances. Sites of similar class, show different soil effects both in shape, amplitude and in frequency. In many cases there is no correlation between amplification and VS, and in other cases, the scatter is unacceptably high.展开更多
The basis for the NEHRP site coefficients is summarized in the paper. The comparison of site classification between China and US code provisions has been carried out. The relationship between two site classifications ...The basis for the NEHRP site coefficients is summarized in the paper. The comparison of site classification between China and US code provisions has been carried out. The relationship between two site classifications has been found by the analysis of wave velocity of site soil. Thus amplitude-dependent site amplification factors for China site classification has been gained by transformation from US amplification factors. Two amplification factors are specified： Fa for short periods and Fv for longer periods. On the contrast, there is only one long period factor and not a short period factor in the current China code provision.展开更多
文摘Basic concepts of seismic zonation in Russia are the degree of intensity and soil categories that correspond to discrete structure in the ratio “seismic impact-ground reaction”. Meanwhile, the parameters of seismic effects, and the parameters of soil properties are continuous in the space. The report expounds the basic theory, adequately representing the above mentioned continuality. Thus, many the concepts of seismic zonation, used now, become either more correct, or unnecessary.
文摘In this study we examined the applicability of the NEHRP soil classification which is based on the VS,30 parameter and the corresponding Fa and Fv factors to correct acceleration response spectra for local site classification. We calculated acceleration response spectra (10% in 50 years) for more than 1900 sites across Israel. Computations were made for hard rock conditions and for the actual site conditions, while considering nonlinear response of the soils. Based on synthetic acceleration response spectra of real sites (using stochastic procedures), it is concluded that generalizing site classification and consequently, amplification, by means of a single parameter VS, 30 is not recommended. The geology of Israel is complex and may vary significantly over short distances. Sites of similar class, show different soil effects both in shape, amplitude and in frequency. In many cases there is no correlation between amplification and VS, and in other cases, the scatter is unacceptably high.
基金Joint Seismological Science Foundation of China (A07046).
文摘The basis for the NEHRP site coefficients is summarized in the paper. The comparison of site classification between China and US code provisions has been carried out. The relationship between two site classifications has been found by the analysis of wave velocity of site soil. Thus amplitude-dependent site amplification factors for China site classification has been gained by transformation from US amplification factors. Two amplification factors are specified： Fa for short periods and Fv for longer periods. On the contrast, there is only one long period factor and not a short period factor in the current China code provision.
