基于地震易损性解析函数的概率地震风险应用研究

在采用全概率方法的基于性能的地震工程研究中，定量反映地震作用和工程结构中存在的不确定性是研究的关键。利用地震易损性和地震风险的概率解析函数，针对一栋按我国相关规范设计的五层三跨钢筋混凝土框架结构进行了地震易损性分析和风险评估。采用100条实际地震动作为输入以考虑地震动的不确定性，提出了基于控制变换拉丁超立方体抽样技术的随机Pushover方法以考虑结构不确定性对其抗震能力的影响。结果表明：算例结构在50年内发生完全破坏的概率不超过2%，发生严重破坏的概率不超过10%，发生轻微破坏的概率基本不超过63.2%，基本满足我国“小震不坏、中震可修、大震不倒”的三水准要求。

Application study of probabilistic seismic risk assessment based on analytical functions of seismic fragility

For the performance-based earthquake engineering (PBEE) based on the total probability method, it is the key issue to quantitatively consider the influences of the uncertainties on earthquake actions and structures. Using the analytical functions of seismic fragility and probabilistic seismic risk, a five-story and three-bay reinforced concrete (RC) frame structure which was designed according to the current Chinese codes was selected as the study case to conduct seismic fragility assessment and seismic risk evaluation. One hundred real ground motions were selected as inputs to incorporate the earthquake uncertainty; and a random Pushover method based on a transformation controlled Latin hypecube sampling was proposed to determine the influences of structural uncertainties on the corresponding capacity. The results show that the case-study frame approximately has no more than 63.2% exceeding probability of light damage, no more than 10% exceeding probability of medium damage; and no more than 2% exceeding probability of severe damage in 50-year period. Consequently, the case frame approximately satisfies the three-level requirements defined in the seismic design code, i.e., no damage under minor earthquake, no un-repaired damage under moderate earthquake, and no collapse under major earthquake.