数值模拟联合算法及其在润扬大桥可靠度评估中的应用

为了定量研究大跨桥梁在外界随机因素作用下的结构安全性,实现在线状态的可靠度评估,利用可靠度的随机有限元法对润扬大桥悬索桥在正常运营和损伤等多种工况下的结构可靠度进行了数值模拟和可靠度评估。分析中采用蒙特卡罗重要抽样法和中心复合响应面法的联合算法作为数值模拟的基本工具,介绍了联合算法的具体实现途径、随机变量的参数定义并对大跨桥梁基于可靠度指标的评估准则进行了讨论。得到了多个随机变量的概率灵敏度、主要失效模式所对应的可靠度指标及其相应的状态等级。算例分析结果表明,基于随机有限元的可靠度分析方法可以较好地描述大跨桥梁的非线性特征,联合算法的应用提高了可靠度分析的效率和精度,其结果为润扬大桥悬索桥的状态评估和健康监测提供了参考。

Combined numerical simulation method and its application on the reliability assessment of the Runyang Bridge

To obtain the reliability of long span bridges under the influence of external random factors and to realize the online condition assessment,numerical simulation and reliability assessment of the Runyang Suspension Bridge is conducted by using the stochastic finite element method(SFEM).The Monte Carlo Importance Sampling method and the Central Composition Response Surface method are combined as the basic tool of numerical simulation.The definition of random factors,the application of the combined method and the assessment criterion based on reliability index are introduced and discussed.The probability sensitivities between random variables are analyzed and the reliability index and the corresponding condition classes are obtained.Examples indicate that the reliability analysis using SFEM can describe the nonlinearity of long span bridges and the combined method can increase the efficiency and accuracy of reliability analysis.