基于Gamma过程的桥梁检测维护策略优化研究
发布时间:2018-03-01 13:08
本文关键词: 桥梁检测维护策略 Gamma过程 全寿命周期成本 钢筋锈蚀 疲劳裂纹 优化 遗传算法 出处:《中南大学》2014年硕士论文 论文类型:学位论文
【摘要】:摘要:我国目前正处于大规模桥梁建设阶段,桥梁在环境和车辆等荷载共同作用下其使用性能不断退化,而与之相对的则是不断增长的荷载。随着使用时间的增加,结构的失效概率将逐渐变大。为了保证桥梁的正常使用性能,在其运营阶段必须进行必要的检测和维护。然而,面对量大面广的桥梁结构,桥梁管理部门拥有的维护资源是有限的,如何使用有限的资源来获得最大的社会和经济效益是业主们普遍关心的问题。本文采用Gamma过程模拟桥梁使用性能退化以考虑使用性能退化的不确定性;同时考虑检测手段的不确定性和不同的维护措施对结构使用寿命的影响,以最大化结构使用寿命和最小化检测维护成本为目标,建立了基于Gamma过程的桥梁检测维护策略多目标优化计算模型,采用遗传算法计算得到了该优化问题的Pareto优化解集,可以为业主或者桥梁管理单位制定检测维护计划提供依据。 论文的主要研究工作包括: 1.介绍了Gamma过程的基本原理以及模拟退化过程的计算方法,将结构使用性能退化到预设极限值的时间作为结构的使用寿命预测值。考虑桥梁检测的不确定性以及不同的维护措施对结构使用性能的影响,使用决策树模型计算不同检测维护策略下基于概率的桥梁的最终使用寿命。 2.将桥梁全寿命周期检测维护成本分为检测成本、维护成本和失效风险成本,考虑桥梁检测的不确定性,根据决策树模型计算得到不同检测维护策略下的检测维护的总成本。以最大化结构使用寿命和最小化检测维护成本为目标函数,建立了桥梁检测维护策略的多目标优化计算模型。 3.以广西铁山港大桥30m跨钢筋混凝土板梁为工程背景,采用氯离子侵蚀引起的钢筋局部锈蚀深度表征结构的使用性能的退化程度;采用Gamma过程模拟其性能退化,对空心板底部钢筋锈蚀的检测方法、检测时间以及维护决策指标进行优化计算,得到了Pareto优化解集。计算结果表明:Pareto优化解集可以为制定混凝土桥中钢筋锈蚀的检测维护策略提供依据,业主可以根据自身预算以及对结构的使用寿命期望选择相应的决策策略。 4.以某钢箱梁纵向加劲肋的疲劳检测维护为例,采用构件中疲劳裂纹长度表征结构的使用性能的退化程度;采用Gamma过程模拟其性能退化,对钢桥的疲劳裂纹维护措施、维护时间进行优化计算,得到了Pareto优化解集。计算结果表明:本文所提出的方法也可以用于钢桥构件疲劳的检测维护策略优化计算,Pareto优化解集可以为制定钢桥构件的疲劳检测维护策略提供依据。
[Abstract]:Absrtact: at present, our country is in the large-scale bridge construction stage, the bridge under the environment and the vehicle and so on load joint action uses the performance to degenerate unceasingly, but the opposite is the increasing load. In order to ensure the normal service performance of the bridge, it is necessary to carry out necessary inspection and maintenance during the operation phase. However, in the face of a wide range of bridge structures, Bridge management has limited maintenance resources, How to use limited resources to obtain the maximum social and economic benefits is a common concern of the owners. In this paper, the Gamma process is used to simulate the degradation of bridge performance to consider the uncertainty of performance degradation. At the same time, considering the uncertainty of the testing method and the influence of different maintenance measures on the service life of the structure, the aim is to maximize the service life of the structure and minimize the cost of inspection and maintenance. The multi-objective optimization calculation model of bridge detection and maintenance strategy based on Gamma process is established, and the Pareto optimization solution set of the optimization problem is obtained by using genetic algorithm, which can provide the basis for the owner or the bridge management unit to formulate the inspection and maintenance plan. The main research work of the thesis includes:. 1. The basic principle of Gamma process and the calculation method of simulating degenerate process are introduced. Considering the uncertainty of bridge detection and the influence of different maintenance measures on the service performance of the structure, the time when the performance of the structure is degraded to the preset limit value is taken as the prediction value of the service life of the structure. Decision tree model is used to calculate the final service life of probabilistic bridges under different detection and maintenance strategies. 2. The whole life cycle detection and maintenance cost of bridge is divided into detection cost, maintenance cost and failure risk cost, and the uncertainty of bridge detection is considered. According to the decision tree model, the total cost of detection and maintenance under different detection and maintenance strategies is calculated, and the objective function is to maximize the service life of the structure and minimize the cost of detection and maintenance. A multi-objective optimization model of bridge detection and maintenance strategy is established. 3. Taking the 30m span reinforced concrete slab beam of Tieshangang Bridge in Guangxi as the engineering background, the local corrosion depth of steel bar caused by chloride ion erosion is used to characterize the degradation degree of the performance of the structure, and the Gamma process is used to simulate the degradation of the structure's performance. The detection method, detection time and maintenance decision index of steel bar corrosion at the bottom of hollow slab are optimized and calculated. The optimal solution set of Pareto is obtained. The calculation results show that the solution set can provide a basis for the determination and maintenance of steel corrosion in concrete bridges. The owner can choose the corresponding decision strategy according to his own budget and the life expectancy of the structure. 4. Taking the fatigue detection and maintenance of longitudinal stiffener of a steel box girder as an example, the fatigue crack length in the member is used to characterize the degradation degree of the structural performance, and the Gamma process is used to simulate the degradation of the performance and the maintenance measures for the fatigue crack of the steel bridge. The maintenance time is calculated optimally. The results show that the method presented in this paper can also be used to optimize the fatigue detection and maintenance strategy of steel bridge members. The Pareto optimal solution set can provide a basis for the formulation of fatigue detection and maintenance strategies for steel bridge members.
【学位授予单位】:中南大学
【学位级别】:硕士
【学位授予年份】:2014
【分类号】:U445.7
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