基于凸集模型的桥梁非概率可靠度研究

发布时间：2018-03-18 20:36

本文选题：桥梁工程　切入点：承载力评估　出处：《云南大学》2015年硕士论文　论文类型：学位论文

【摘要】：在工程结构中存在着不确定性,包括随机性、模糊性和未确知性。而针对随机性的概率可靠度理论在桥梁承载力评估过程中表现出的本质上的不协调和不适应,因此本文拟对既有桥梁结构评估的非概率时变可靠度进行研究,提出对既有桥梁结构进行非概率可靠度评估的新技术。本文着重解决非概率可靠度理论在桥梁工程中所涉及到的根本问题,其主要研究内容如下：(1)基于凸集的椭球模型结构非概率可靠度计算的基本理论研究,得出基于凸集的椭球模型的相关数学表达式,分析该模型的适用条件和优缺点。(2)基于区间运算的可靠度分析,主要包括区间数的定义,区间的运算格式,区间的获取方法研究,以及常见结构功能衰减参数的表达形式。然后研究基于桥梁的结构抗力与荷载效应的非概率可靠度指标的具体求解方法。(3)结构非概率可靠度评估体系研究,通过对基于实际检测数据的非概率时变可靠度评定理论的研究,可以对影响现役钢筋混凝土结构桥梁抗力的诸多因素进行分析,并研究在这些因素影响下的结构性能退化机理和随时间变化的数学模型,可得出在这些因素的综合影响下结构的时变抗力值。(4)对现役钢筋混凝土拱桥的荷载效应进行分析,在同时考虑混凝土损失和钢筋损伤及材料劣化的情况下,分析了矩形截面既有钢筋混凝土构件偏心受压的时变计算模型,给出了时变抗力计算的简化公式,针对其计算特点,给出了判别大小偏心受压的判断条件。极大的简化了桥梁评估的工作量和难度。本文将突破传统桥梁承载力评定仅仅依赖概率可靠度理论的局面,使结构的不确定性分析更为全面,有助于更加客观真实地对桥梁结构进行综合评定。
[Abstract]:There are uncertainties in engineering structures, including randomness, fuzziness and unascertained. Therefore, the non-probabilistic time-varying reliability of existing bridge structures is studied in this paper. A new technique for non-probabilistic reliability evaluation of existing bridge structures is proposed in this paper, which focuses on solving the fundamental problems involved in the theory of non-probabilistic reliability in bridge engineering. The main research contents are as follows: (1) the basic theory of non-probabilistic reliability calculation of ellipsoidal model structure based on convex set is studied, and the relevant mathematical expressions of ellipsoid model based on convex set are obtained. (2) based on the reliability analysis of interval operation, including the definition of interval number, the operation format of interval, the acquisition method of interval, the application conditions and advantages and disadvantages of the model are analyzed. Then, the non-probabilistic reliability evaluation system based on the bridge resistance and load effect is studied, which is based on the concrete solution method of non-probabilistic reliability index. By studying the theory of non-probabilistic time-varying reliability evaluation based on the actual test data, many factors affecting the resistance of existing reinforced concrete bridges can be analyzed. Under the influence of these factors, the mechanism of structural performance degradation and the mathematical model of the variation with time are studied. The time-varying resistance value of the structure under the influence of these factors is obtained. 4) the load effect of the active reinforced concrete arch bridge is analyzed. Considering the loss of concrete, damage of steel bar and deterioration of materials, the time-varying calculation model of eccentric compression of existing reinforced concrete members with rectangular section is analyzed, and a simplified formula for calculating time-varying resistance is given. The condition of judging the eccentric compression is given, which greatly simplifies the workload and difficulty of bridge evaluation. This paper will break through the situation that traditional bridge bearing capacity evaluation only depends on probabilistic reliability theory. It makes the uncertainty analysis of the structure more comprehensive and helps to evaluate the bridge structure more objectively and realistically.
【学位授予单位】：云南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U441

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