风险导向地震动参数决策及参数影响分析

Risk-targeted ground motions can consider seismic hazards and structural fragility simultaneously, which results in a consistent risk of collapse for the buildings in different regions. Therefore, taking risk-targeted peak ground acceleration and risk-targeted spectral acceleration as risk-targeted ground motion parameters, based on the principle of risk-targeted, the risk-targeted ground motion parameters of generic sites and specific sites were obtained through analytical method and risk integral method, respectively. For specific sites, control points in Baqiao and Changan region were taken for a case study. Then, the comparison of the ground motion parameters between generic sites and specific sites was conducted, and the effect of logarithmic standard deviation on the risk-targeted decision parameters of seismic ground motions and on the risk-targeted ground motion parameters was investigated. The results show that with the increase of logarithmic standard deviation, the target collapse risk does not change significantly at first and then increases; the conditional collapse probabilities corresponding to the design basis earthquake increases gradually at first and then decreases slightly; the conditional collapse probabilities corresponding to the very rare earthquake decreases gradually; the risk-targeted design basis earthquake and the risk-targeted very rare earthquake are decrease and increase, respectively. The conditional collapse probabilities corresponding to the maximum considered earthquake and the risk-targeted maximum considered earthquake all do not change significantly with the increase of logarithmic standard deviation. The average rate of change of the risk-targeted maximum considered earthquake corresponding to peak ground acceleration is 2.95%, which is the largest. The research results of this paper can provide decision support for seismic design based on uniform risk.