Probabilistic Seismic Hazard Analysis Incorprating Site Amplification

In traditional engineering seismic hazard analyze, probability based design ground motion for soil sites is commonly conducted by following steps:(1) conduct the Probabilistic Seismic Hazard Analysis (PSHA) for a rock site condition, develop a Uniform Hazard Spectrum(UHS) for rock site and synthesizing ground motion; (2) conduct deterministic site specific response analyze.This study presents an effective probabilistic approach for incorporating site effect into China PSHA. Probobility distribution of site Amplification Factor (AF) is founded by soil response analyze. As an example,93 sites classifiedâ…¡are divided into 3 categry by structure of soil layer. Using 614 accelerograms from NGA acceleration database as basic input motions, we calculate the ground motion at the surface of a typical soil site, and investigate the probability distribution model of soil AF. Then we establish the AF model of PGA for site classâ…¡-2. Comparing with traditional PSHA method, ground hazard result shows that at higher probability exceedance level, the results from two method are equivalent, but at higher probability exceedance level, result from our method is higher(about 10%),because of concerning the uncertainty of site effect. This method reduces much work such as design earthquake, synthesizing ground motion in hazard analyze. Probability exceedance curve and Uniform Hazard Spectrum (UHS) of soil site can be calculated by this method which considers uncertainty of site effect effectively.