大跨度单索面钢桥桁梁斜拉桥施工风险分析

发布时间：2018-01-30 22:42

本文关键词： 斜拉桥施工风险分析层次分析法蒙特卡罗理论 RBF神经网络单索面　出处：《重庆交通大学》2014年硕士论文　论文类型：学位论文

【摘要】：单索面钢桁梁斜拉桥属于多次超静定结构，索、塔、梁的连接构造复杂，设计计算难度大，高空作业较多，索力大且集中，，单索钢绞线数量大，抗扭能力差，斜拉索的均匀性和索力调整不易控制，且国内外对该种类型桥梁理论认识不足，施工控制难度大，因而在施工期间存在着较大的风险。为了提高工程质量，减少工程事故的发生，对单索面钢桁梁斜拉桥施工期间进行风险分析并建立风险评估系统是十分必要的。本文依托于千厮门大桥，结合桥梁的具体施工特点，运用层次分析法-灰色关联理论-有限元模型-蒙特卡罗理论-RBF神经网络综合评价法对大跨径单索面公轨两用钢桁梁斜拉桥施工风险进行系统研究。由于大桥体系复杂，结合层次分析法层次分明、可将定性问题定量化的特点，利用层次分析法对桥梁施工过程中的风险源进行全面辨识，确定桥梁施工期间主要风险源及其相对重要性权重，建立桥梁风险因素排序表。由于千厮门大桥结构形式的选取具有灰色系统的特征，采用灰色关联分析法结合层次分析法证明了千厮门大桥采用单索面结构形式的风险可控性。结合有限元分析、蒙特卡罗理论、RBF神经网络提出风险的综合评价方法，对千厮门大桥最大悬臂状态悬臂端的竖向位移进行定量分析，通过建立有限元模型，确定大桥在确定工况及参数条件下的悬臂端位移。为使材料参数达到统计规律要求，因而引入径向基神经网络，对桥梁悬臂端位移进行定量分析，结合蒙特卡罗理论，确定风险发生的概率，使得风险分析可信度增加本文附录中列举了千厮门大桥较高权重风险因素的预防措施。本文根据层次分析法-灰色系统理论-有限元模型-蒙特卡罗理论-RBF神经网络建立大跨径单索面斜拉桥施工风险定量分析模型，并基于此对桥梁施工期的风险进行评估，提高了风险分析的客观性，可信度较高。这在桥梁定量风险分析上是一种新的探索，希望能为大跨径单索面钢桁梁斜拉桥施工期风险分析理论的发展提供参考。
[Abstract]:Single cable plane steel truss girder cable-stayed bridge belongs to many statically indeterminate structure, the connection structure of cable, tower and beam is complicated, the design and calculation is difficult, the aerial work is more, the cable force is large and concentrated, the single cable steel strand quantity is large, the torsional ability is poor. The uniformity and cable force adjustment of stay cables is not easy to control, and the theory of this type of bridge is not well understood at home and abroad, and the construction control is difficult, so there is a great risk during the construction period, in order to improve the quality of the project. To reduce the occurrence of engineering accidents, it is necessary to carry out risk analysis and establish a risk assessment system for steel truss girder cable-stayed bridges with single cable plane during construction. This paper is based on the Qiansimmen Bridge, combined with the specific construction characteristics of the bridge. The comprehensive evaluation method of analytic hierarchy process (AHP), grey relation theory, finite element model, Monte Carlo theory and RBF neural network is used to study the construction risk of large-span steel truss bridge with common rail with single cable plane. Because of the complexity of the bridge system and the distinct hierarchy process, the qualitative problems can be quantified and the risk sources in the process of bridge construction can be fully identified by the analytic hierarchy process. The main risk sources and their relative importance weights during bridge construction are determined and the ranking table of bridge risk factors is established. Because the selection of structural form of Qiansimimen Bridge has the characteristics of grey system, the risk controllability of Qiansimimen Bridge using single cable plane structure is proved by using the grey relational analysis method and the analytic hierarchy process. Combined with finite element analysis, Monte Carlo theory and RBF neural network put forward a comprehensive risk evaluation method to quantitatively analyze the vertical displacement of the maximum cantilever end of Qianshuomen Bridge. By establishing finite element model, the cantilever end displacement of the bridge under certain working conditions and parameters is determined. In order to make the material parameters meet the requirements of statistical law, radial basis function neural network is introduced. The quantitative analysis of bridge cantilever end displacement and the Monte Carlo theory are used to determine the probability of risk occurrence, which increases the reliability of risk analysis. In the appendix of this paper, the preventive measures of high weight risk factors of Qianshuimen Bridge are listed. In this paper, the quantitative analysis model of construction risk of long-span cable-stayed bridge with single cable plane is established based on the analytic hierarchy process (AHP), grey system theory, finite element model-Monte Carlo theory and RBF neural network. Based on this, the risk of bridge construction period is evaluated, which improves the objectivity and credibility of risk analysis, which is a new exploration in bridge quantitative risk analysis. This paper hopes to provide a reference for the development of risk analysis theory of long span single cable plane steel truss girder cable-stayed bridge during construction.
【学位授予单位】：重庆交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U445

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