中国广义条件参数目标谱构建方法及地震动输入

为了在时程分析中考虑加速度反应谱之外的强度指标，构建了兼顾危险一致性和参数完备性的广义条件参数目标谱用于地震动记录选取。结合我国地震安全性评价中设定地震解耦的特点，提出利用各个潜源微元的贡献率作为权重计算条件均值向量，进而通过拉丁超立方分层抽样得到多元正态分布假设下的广义强度参数条件分布，即广义条件参数目标谱。通过K-S假设检验的D值法在数据库中搜寻最符合目标分布的记录组合作为选波结果。以我国某工程的地震安全性评价为实例，构建同时考虑幅值、频谱、持时以及谱强度指标的广义条件参数目标谱。结果表明：考虑设定地震贡献率修正的强度指标目标分布与单一设定地震的结果存在差异；广义条件谱记录选取结果的危险性曲线和场址概率危险性分析的结果基本一致；在低超越概率水平下， 广义条件谱下的危险一致性不及仅考虑加速度反应谱指标的条件谱。

Generalized conditional target spectrum for ground motion input in China

To consider the intensity measures (IM) other than the acceleration response spectrum in time history analysis, a generalized conditional target spectrum was constructed considering hazard consistency and parameter sufficiency. Considering the characteristics of seismic disaggregation in the seismic safety evaluation work in China, the contribution ratio of each microelement in the potential source area was implemented as the weight in calculating the conditional mean IM vector. Subsequently, the generalized conditional IM distribution (i.e., the generalized conditional target spectrum) based on the multivariate normal distribution assumption was obtained by Latin hypercube stratified sampling. The D-value of K-S hypothesis test was used to search for the recordings closely matching the target IM distribution in the ground motion database. Taking a seismic safety evaluation project in China as an example, the generalized conditional target spectrum was constructed considering the amplitude, acceleration spectrum, duration, and spectrum intensity. The results show that the IM distribution considering the contributions of potential earthquake scenarios is different from the results using a single earthquake scenario. It shows that the hazard curve derived by the selected results according to the generalized conditional target spectrum matches well with the results of site-specific probability seismic hazard assessment.Under low exceedance rate, the hazard consistency of generalized conditional target spectrum is not as good as the conditional spectrum that only take into account the spectral acceleration.