大跨PC梁桥退化预测模型与维护策略优化研究

发布时间：2018-11-19 14:47

【摘要】：近年来，随着国家基础设施建设的快速发展，大跨预应力混凝土桥梁以其跨越能力大、整体性和连续性好、行车平顺舒适、桥型简洁美观、经济实用等一系列优点，成为我国公路建设中最主要的桥型之一。但桥梁结构长期在自然环境与使用条件下逐渐老化、损伤甚至破坏，影响到结构物的安全性和使用功能。因此，掌握桥梁的性能状况，准确预测结构的退化趋势对大跨预应力混凝土桥梁的维护管理意义重大。本文基于桥梁结构可靠度β，采用基于数值模拟技术的可靠性分析方法，建立了大跨预应力混凝土桥梁基于开裂和跨中挠度的退化预测模型，提出了基于遗传算法的桥梁最优维护管理策略，本论文主要的研究工作包括： (1)介绍了传统的一次二阶矩法和两种数值模拟方法—蒙特卡罗法和响应面法各自的基本原理、特点以及算法步骤。通过薄板算例，利用ANSYS程序中APDL语言编制命令流程序，分别用蒙特卡罗法和响应面法对其进行可靠度计算。并对比分析了两种数值模拟方法的计算结果以及各自的运算特点。 (2)以大跨预应力混凝土梁桥北江特大桥工程为背景，，利用ANSYS程序中的参数化语言（APDL）编写命令流文件，实现结构建模以及分析过程的自动化；采用基于数值模拟技术的响应面法，对影响结构正常使用极限状态下的裂缝及跨中挠度进行了可靠性分析。 (3)根据国内外相关文献提出的混凝土强度退化机理以及钢筋腐蚀规律，建立了混凝土强度时变模型以及考虑腐蚀钢筋的截面积和强度的时变模型。并将抗力的各随机变量的时变模型引入基于数值模拟技术的响应面法的时变可靠度计算程序中，对北江特大桥进行了裂缝及跨中挠度的时变可靠度分析。 (4)在北江大桥无维护活动时基于裂缝和跨中挠度的可靠指标劣化曲线基础上，采用遗传算法，编写了最优维护策略程序，对大跨预应力混凝土梁桥的维护策略进行优化，计算得到了北江特大桥在寿命周期内的最优维护管理计划以及相应的维护成本。
[Abstract]:In recent years, with the rapid development of national infrastructure construction, long-span prestressed concrete bridges have a series of advantages, such as large span capacity, good integrity and continuity, smooth and comfortable driving, simple and beautiful bridge type, economic and practical, etc. It has become one of the most important bridges in highway construction in China. However, the bridge structure is aging, damaged and even destroyed in the natural environment and service conditions for a long time, which affects the safety and use function of the structure. Therefore, it is of great significance for the maintenance and management of long-span prestressed concrete bridges to grasp the performance of bridges and accurately predict the structural degradation trend. In this paper, based on the reliability 尾 of bridge structure and the reliability analysis method based on numerical simulation technique, a degradation prediction model of long-span prestressed concrete bridge based on crack and mid-span deflection is established. The optimal maintenance and management strategy of bridge based on genetic algorithm is proposed. The main work of this thesis is as follows: (1) the basic principles, characteristics and steps of the traditional first-order second-moment method and two numerical simulation methods-Monte Carlo method and response surface method are introduced. Through the example of thin plate, the command flow program is compiled by APDL language in ANSYS program, and the reliability of the program is calculated by Monte Carlo method and response surface method, respectively. The results of two numerical simulation methods and their characteristics are compared and analyzed. (2) under the background of Bei Jiang Bridge Project of long-span prestressed concrete beam bridge, the command flow file is compiled by using the parameterized language (APDL) in ANSYS program to realize the automation of structural modeling and analysis process; The response surface method based on numerical simulation technique is used to analyze the reliability of cracks and mid-span deflection under the limit state of normal use of the structure. (3) according to the mechanism of concrete strength degradation and the rule of reinforcement corrosion, the time-varying model of concrete strength and the time-varying model considering the section area and strength of corroded steel bar are established. The time-varying model of each random variable of resistance is introduced into the time-varying reliability calculation program of response surface method based on numerical simulation technology, and the time-varying reliability analysis of the crack and mid-span deflection of Beijiang Bridge is carried out. (4) on the basis of reliable index deterioration curve of crack and mid-span deflection of Beijiang Bridge without maintenance, the optimal maintenance strategy program is compiled by genetic algorithm to optimize the maintenance strategy of long-span prestressed concrete beam bridge. The optimal maintenance management plan and the corresponding maintenance cost of Beijiang Bridge during its life cycle are calculated.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U445.7

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