非线性参数拟合的桥梁概率地震需求模型研究

A probabilistic seismic demand model by nonlinear parameter fitting method

针对云图法建立概率地震需求模型时部分工程需求参数(EDP)与地震动强度参数(IM)间不满足对数线性回归关系假设的问题,建立某三跨混凝土连续梁桥的3D有限元模型。采用IDA方法建立桥梁概率地震需求模型,并以IDA分析结果为基准,在同一地震动参数下,采用基于不同拟合方式的云图法建立概率地震需求模型并得到了结构在不同破坏状态下的易损性曲线。研究表明,当EDP与IM之间的数量关系不满足云图法对数线性关系基本假设时,选择恰当的非线性参数拟合方式可以显著提高云图法建立概率地震需求模型的精度。

In order to solve the problem that when establishing a probabilistic seismic demand model by the cloud method,some Engineering Demand Parameters（ EDPs） and ground motion intensity（ IM） parameters do not meet the assumption of logarithmic linear regression relationship,a 3D finite element model of a three-span concrete continuous beam bridge was established. The bridge probabilistic seismic demand model was first established by incremental dynamic analysis（ IDA）. Taking the IDA analysis result as the benchmark,under the same seismic motion parameters,and using the cloud method based on various fitting modes to establish a probabilistic seismic demand model,the fragility curve under different breaking states was obtained. The results show that,when the quantitative relationship between EDP and IM does not meet the basic logarithmic linear relationship assumption of the cloud method,choosing appropriate nonlinear parameter fitting mode can significantly improve the precision of the probabilistic seismic demand model established by the cloud method.