Site coefficients suitable to China site category

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.