基于可变模糊集理论的寒旱地区在役混凝土桥梁耐久性评估

发布时间：2018-08-04 15:29

【摘要】：在混凝土桥梁的使用过程中,往往由于耐久性问题而使桥梁提前失效。影响桥梁耐久性的因素很多,有工作环境、交通量以及自身材料缺陷等,在这些影响因素中,工作环境会使在役混凝土桥梁的耐久性问题因地域不同而千差万别。和普通地区相比,寒旱地区有着更为复杂的环境状况和恶劣的气候条件,位于该地区的桥梁结构所出现的耐久性问题也更为严重。在役混凝土桥梁一旦出现耐久性损伤,不仅会严重阻碍交通系统的畅通运行,甚至给国家经济和人民财产安全带来不可估量的损失。因此,迫切需要解决寒旱地区在役混凝土桥梁的耐久性问题,而解决该问题的关键是对其耐久性状况进行合理地评估。本文以寒旱地区在役混凝土桥梁的耐久性为研究对象,根据在役混凝土桥梁耐久评估理论相关知识,结合寒旱地区桥梁耐久性的特点,深入分析了影响其耐久性的因素,并遵循评估指标体系的建立原则,构建了寒旱地区在役混凝土桥梁耐久性评估指标体系。通过参考国内外现行在役混凝土桥梁耐久性评估标准及相关规范的规定,确定了寒旱地区在役混凝土桥梁的耐久性评估等级和各评估指标的判定等级。在对评估指标权重确定方法及综合评估方法对比分析的基础上,结合构建的寒旱地区在役混凝土桥梁耐久性评估指标体系,建立了基于模糊可变集理论的寒旱地区在役混凝土桥梁耐久性评估模型,并详细阐述了模型运用的具体步骤。在该模型中,用层次分析法(AHP)确定评估指标权重,引入可变模糊集理论进行综合评估,尝试通过新的组合方法完成对寒旱地区在役混凝土桥梁耐久性的评估。层次分析法(AHP)可以将指标的定性分析与定量分析相结合,得到较为准确的权重计算结果。可变模糊集理论在解决指标体系比较复杂的问题时,可以针对不同类型的评估指标灵活地确定不同等级下的评估区间,并且将定量指标的实测值运用到评估中,使得评估结果更为客观。通过具体的工程实例,验证了构建的基于模糊可变集理论的寒旱地区在役混凝土桥梁耐久性评估模型的可行性和有效性。根据实例分析可知,采用本文所建立的模型对寒旱地区服役期混凝土桥梁的耐久性进行评估是完全可行的,评估结果可以反映桥梁的耐久性状况,有助于采取相应的补救措施解决耐久性问题,保证桥梁的安全使用。
[Abstract]:In the course of the use of concrete bridges, it often causes the bridge to fail in advance because of the durability problem. There are many factors affecting the durability of the bridge, such as the working environment, the traffic volume and the defects of its own materials. In these factors, the working environment will make the durability of the concrete bridges vary in different regions because of the region. There are more complex environmental conditions and harsh climate conditions in the area of cold and dry areas, and the durability problems of the bridge structures in the area are more serious. Once the durability damage occurs in the service concrete bridges, it will not only seriously impede the smooth operation of the traffic system, but even give the national economy and the people's property safety. Therefore, there is an immeasurable loss. Therefore, it is urgent to solve the durability of the concrete bridges in the cold and drought areas, and the key to solve the problem is to reasonably evaluate the durability of the bridge. In this paper, the durability of the active concrete bridges in the cold and dry areas is the research object, and the relevant theory of the durability of the concrete bridges in service is related to the theory related to the durability of the concrete bridges in service. Knowledge, combined with the characteristics of the durability of bridges in cold and dry areas, deeply analyzes the factors affecting its durability, and follows the principle of establishing the evaluation index system, and constructs the durability evaluation index system of the existing concrete bridges in the cold and dry areas. The durability evaluation grade of the active concrete bridge in the cold and dry areas and the judgement grade of each evaluation index are determined. On the basis of the method of determining the weight of the evaluation index and the comparison and analysis of the comprehensive evaluation method, the fuzzy variable set theory is established on the basis of the construction of the construction of the durability evaluation index system of the existing concrete bridges in the cold and dry areas. The concrete bridge durability assessment model in the cold and drought area, and the concrete steps of the model application are expounded in detail. In this model, the evaluation index weight is determined by the analytic hierarchy process (AHP), and the variable fuzzy set theory is introduced to comprehensive evaluation, and the durability evaluation of the concrete bridges in the cold and dry areas is completed by the new combination method. The analytic hierarchy process (AHP) can combine the qualitative analysis with the quantitative analysis to obtain more accurate results of weight calculation. Variable fuzzy set theory can flexibly determine the evaluation interval under different types of evaluation index for solving the complex problem of the index system, and make the quantitative index real. The evaluation results are used to make the evaluation result more objective. Through concrete engineering examples, the feasibility and effectiveness of building durability evaluation model of concrete bridges in cold and dry areas based on fuzzy variable set theory are verified. It is completely feasible to evaluate the durability of the bridge. The evaluation results can reflect the durability of the bridge, and help to take corresponding remedial measures to solve the durability problem and ensure the safe use of the bridge.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U446;U448.33

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