车辆超载对RC梁桥疲劳可靠性的影响分析

发布时间：2018-06-29 02:32

本文选题：RC梁桥 + 车辆超载　；参考：《长沙理工大学》2014年硕士论文

【摘要】：钢筋混凝土梁桥是公路、铁路桥梁中常见的结构之一,其以构造简单、制作方便、造价经济等优点,在中小跨径公路桥梁中得到了广泛的应用。在我国,由于设计标准的相对滞后以及追求经济效益的最大化导致公路桥梁车辆超载现象客观存在。工程实践表明：尽管一次偶然超载不一定对桥梁造成明显结构损伤,但是反复的超载作用将式结构的疲劳损伤加剧,增大失效风险,减短使用寿命,提高维修成本。因此,研究超载运营下桥梁疲劳损伤规律并进行安全评估有重要现实意义。本文首先对结构可靠度的基本概念、常用计算方法、疲劳问题的分析方法以及三种疲劳可靠度分析模型进行了简要的阐述,为后续分析计算车辆超载对钢筋混凝土桥梁疲劳可靠性的影响工作提供了理论基础。然后从规范方法角度入手,分析了车辆超载与疲劳可靠性、疲劳寿命的关系；并以传统的用于疲劳可靠性分析的累积损伤模型和英国BS5400规范中标准疲劳车为基础,以一典型20m跨钢筋混凝土简支T梁桥为背景,研究了车辆超载对钢筋混凝土梁桥的疲劳可靠度的影响和车辆超载与交通量增长同时作用下该钢筋混凝土梁桥的疲劳可靠度的时变规律及其对疲劳寿命的影响。研究表明：在相同的使用寿命情况下,超载水平越高,细节的疲劳可靠度指标越低,发生疲劳失效的概率相应也越大；同时考虑超载与交通量增长将大大缩短桥梁的疲劳寿命,与只考虑超载情况相比,服役后期细节的疲劳可靠度指标将急剧减小,桥梁在设计基准期内发生疲劳破坏的风险将显著增加,疲劳寿命大大降低。
[Abstract]:Reinforced concrete beam bridge is one of the most common structures in highway and railway bridges. It is widely used in medium and small span highway bridges because of its advantages of simple structure, convenient manufacture and economical cost. In China, the phenomenon of overloading of highway and bridge vehicles exists objectively due to the lag of design standards and the maximization of economic benefits. The engineering practice shows that although a accidental overload does not necessarily cause obvious structural damage to the bridge, repeated overload will aggravate the fatigue damage of the formula structure, increase the risk of failure, reduce the service life and increase the maintenance cost. Therefore, it is of great practical significance to study the fatigue damage law and safety assessment of bridges under overload operation. In this paper, the basic concepts of structural reliability, common calculation methods, fatigue analysis methods and three kinds of fatigue reliability analysis models are briefly described in this paper. It provides a theoretical basis for the subsequent analysis and calculation of the influence of vehicle overload on the fatigue reliability of reinforced concrete bridges. Then, the relationship between vehicle overload and fatigue reliability and fatigue life is analyzed from the point of view of specification method, and based on the traditional cumulative damage model for fatigue reliability analysis and the standard fatigue vehicle in British BS5400 Code. Taking a typical 20m span reinforced concrete simply supported T-beam bridge as the background, The influence of vehicle overload on the fatigue reliability of reinforced concrete beam bridge is studied. The time-varying law of fatigue reliability and its influence on fatigue life of the reinforced concrete beam bridge under the simultaneous action of vehicle overload and traffic volume are studied. The results show that under the same service life, the higher the overload level, the lower the fatigue reliability index of detail, and the higher the probability of fatigue failure is. Compared with only considering the overload, the fatigue reliability index of the later service details will be reduced sharply, the risk of fatigue failure of the bridge in the design reference period will be increased significantly, and the fatigue life will be greatly reduced.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.4

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