考虑目标谱不确定性及谱形的实际地震动记录优化选取和调整方法

Optimized real ground motion selection and scaling method considering uncertainty and spectral shape of target spectrum

在已有研究成果的基础上,针对基于非线性动力分析的结构抗震性能评估中实际地震动记录的选取和调整进行了研究。为了使地震动输入能够满足工程场点未来可能遭遇的地震危险性水平需求,借助蒙特卡洛模拟方法,考虑地震动谱形的影响,通过生成随机模拟谱来匹配目标谱多元对数正态分布特征,并采用反应谱形参数优化了地震动记录的选取和调整方法。与通常采用的确定性地震动选取方法相比,所提出的方法能够有效匹配目标谱均值、标准差和谱相关性,较好地反映地震危险性水平本身的不确定特征,且具有较高的选取效率和匹配精度。鉴于目标谱不确定性对结构易损性分析结果的重要影响,研究成果能够为设定地震环境下结构抗震性能评估提供合理可靠的方法依据。

Based on the results of previous studies,it focued on the research of real ground motion selection and scaling method for structural performance-based seismic evaluation using nonlinear dynamic analysis. The input of earthquake ground motion should be determined appropriately to make them compatible with the site-specific hazard level considered. Thus an optimized selection and scaling method was established including use of not only Monte Carlo simulation method to create the stochastic simulation spectrum considering the multivariate lognormal distribution of target spectrum,but also a spectral shape parameter. Its applications in structural fragility analysis were demonstrated through case studies. Compared to the previous scheme with no consideration of the uncertainty of target spectrum,the method shown here can make sure that the selected records are in good agreement with the median value,standard deviation and spectral correction of the target spectrum,and greatly reveal the uncertainty feature of site-specific hazard level. Meanwhile,it can help improve computational efficiency and matching accuracy. Given the important infection of target spectrum＇s uncertainty on structural seismic fragility analysis,this work can provide reasonable and reliable basis for structural seismic evaluation under scenario earthquake environment.