基于混合算法的大跨度斜拉桥可靠度评估

发布时间：2018-12-12 15:46

【摘要】：为研究大跨度预应力混凝土(PC)斜拉桥的可靠度评估问题,提出了适用于大跨度PC斜拉桥这类复杂结构可靠性分析的混合算法。该方法综合运用了有限元分析(FEA)、径向基函数(RBF)神经网络、遗传算法(GA)和Monte Carlo重要抽样(MCIS)方法,并对算法中的关键步骤(RBF神经网络的初始样本点设计方法、MCIS的抽样中心点位置等)进行了改进,使结构分析模块与可靠度计算模块智能结合。利用数值算例的可靠度分析对该算法的有效性进行了验证。最后,以一座主跨为420 m的双塔PC斜拉桥为工程背景,进行了正常使用极限状态下的可靠度分析。参数分析表明:在汽车荷载作用下,该斜拉桥的主梁跨中位移超限失效概率比最长斜拉索强度失效概率高;汽车荷载的均值和标准差是影响斜拉桥可靠度的重要因素;随着汽车荷载均值系数的增大,主梁跨中位移超限失效的可靠指标下降的趋势较为显著。
[Abstract]:In order to study the reliability evaluation of long-span prestressed concrete (PC) cable-stayed bridge, a hybrid algorithm for reliability analysis of complex structures such as long-span PC cable-stayed bridge is proposed. The (FEA), radial basis function (RBF) neural network, genetic algorithm (GA) and Monte Carlo important sampling (MCIS) method are used in this method. The key steps of the algorithm (the initial sample point design method of RBF neural network) are discussed. The location of the sampling center of MCIS is improved to combine the structural analysis module with the reliability calculation module. The validity of the algorithm is verified by the reliability analysis of numerical examples. Finally, taking a 420m PC cable-stayed bridge with a main span of 420m as the engineering background, the reliability analysis under the limit condition of normal use is carried out. The parameter analysis shows that the failure probability of the mid-span displacement of the main girder of the cable-stayed bridge is higher than that of the longest cable strength under the action of vehicle load, and the mean and standard deviation of the vehicle load are the important factors affecting the reliability of the cable-stayed bridge. With the increase of the average coefficient of vehicle load, the reliability index of the mid-span displacement of the main beam decreases significantly.
【作者单位】：长沙理工大学土木与建筑学院;桥梁工程湖南省高校重点试验室;
【基金】：国家自然科学基金项目(51378081,51108045) 教育部新世纪优秀人才支持计划项目(NCET-10-0139) 湖南省研究生科研创新项目(CX2013B366)
【分类号】：U448.27

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