钢筋锈蚀和重车超载下服役砼桥梁的疲劳损伤及寿命预测

发布时间：2018-08-20 08:53

【摘要】：在钢筋砼构件(或结构)的疲劳研究中,疲劳试验方法一直以来是国内外研究疲劳问题的主要手段。随着有限元软件的发展优化,数值模拟方法以其成本小、可重复性强等优点逐渐被研究人员所采用。数值模拟与试验手段在钢筋砼疲劳问题的研究中相辅相成,疲劳试验为疲劳数值模拟提供基础,如钢筋砼疲劳数值模拟时用到的初始材料力学参数和疲劳过程中这些参数的退化模型等都是通过疲劳试验手段得到。但是对于疲劳试验周期长、成本高,精确的数值模拟可以弥补疲劳试验的弊端,即以较少次数的疲劳试验为基础,模拟研究钢筋砼构件(或结构)的疲劳性能,乃至整个疲劳加载过程的模拟。但是在当下数值模拟过程中同样面临着很多问题,如钢筋砼构件或(结构)在疲劳加载过程中组成材料的力学参数退化模型和本构关系不同学者通过不同的试验得到形式各异烦简不同的模型,那么如何来合理的选择进行数值模拟才能使模拟结果更加精确和更具有适用性和通用性,是当下丞待解决的问题。针对此本文按照递进的顺序,从组成材料的疲劳性能到钢筋砼构件的疲劳性能再到钢筋砼桥梁结构的疲劳性能进行研究工作,现将本文主要工作简述如下:1.在混凝土材料疲劳已有研究成果的基础上,探讨了混凝土在疲劳加载过程中各力学参数退化模型和本构关系,对其适用性进行分析。建立以最大应力水平予以区分的混凝土疲劳S-N曲线方程。2.在钢筋材料疲劳已有研究成果的基础上,探讨了钢筋在疲劳加载过程中各力学参数退化模型和本构关系,对其适用性进行分析。建立钢筋疲劳剩余强度退化模型。建立通用性较强的钢筋疲劳S-N曲线方程。3.基于多样本试验数据针对各疲劳性能参数退化模型进行优化组分析建立结构疲劳性能有限元数值基准模型(包括静载基准模型和疲劳基准模型)。结合模型试验和相关试验资料探讨结构构件的疲劳性能退化规律,分别针对跨中挠度、混凝土应变、钢筋应变、剩余极限承载力随疲劳加载次数的演变规律建立预测模型,探讨了疲劳荷载作用下挠度、应变、剩余承载力限值,提出更为准确的预测结构剩余使用寿命的方法。4.以基准模型建立方法为基础,对京密公路白河桥建立有限元分析模型。基于实际重车荷载调查资料,建立疲劳车模型,考虑钢筋锈蚀和交通量时变规律,研究了超载、钢筋锈蚀、疲劳共存的情况下桥梁服役年限内的疲劳性能,并对其寿命进行了预测。
[Abstract]:In the fatigue research of reinforced concrete members (or structures), fatigue test methods have always been the main means to study fatigue problems at home and abroad. With the development and optimization of finite element software, numerical simulation method has been gradually adopted by researchers for its advantages of low cost and strong repeatability. Numerical simulation and test methods complement each other in the study of reinforced concrete fatigue problem. Fatigue test provides the foundation for fatigue numerical simulation. For example, the initial material mechanics parameters used in the fatigue numerical simulation of reinforced concrete and the degenerative model of these parameters in the fatigue process are obtained by means of fatigue test. However, the fatigue test cycle is long, the cost is high, and the accurate numerical simulation can make up for the shortcomings of fatigue test, that is, the fatigue performance of reinforced concrete members (or structures) is simulated and studied on the basis of fewer fatigue tests. And even the simulation of the whole fatigue loading process. But in the current numerical simulation process, there are also many problems, For example, in the process of fatigue loading of reinforced concrete members or structures, the degradation model of mechanical parameters and the constitutive relation of materials are obtained by different scholars through different tests. So how to choose the numerical simulation reasonably to make the simulation results more accurate, more applicable and universal, is the current problem to be solved. In this paper, according to the progressive order, from the fatigue behavior of the composition material to the fatigue behavior of the reinforced concrete member and then to the fatigue performance of the reinforced concrete bridge structure, the main work of this paper is summarized as follows: 1. Based on the existing research results of fatigue of concrete materials, the degradation model and constitutive relation of various mechanical parameters during fatigue loading of concrete are discussed, and the applicability of these models is analyzed. The S-N curve equation of concrete fatigue is established, which is distinguished by the maximum stress level. Based on the existing research results of steel bar fatigue, the degenerative model and constitutive relation of various mechanical parameters during fatigue loading of steel bar are discussed, and the applicability of the model is analyzed. The model of fatigue residual strength degradation is established. The S-N curve equation of steel bar fatigue is established. Based on the multi-sample test data, the finite element numerical reference model (including static load reference model and fatigue reference model) for fatigue performance of structures is established by optimizing group analysis for each fatigue performance parameter degradation model. Combined with the model test and related test data, the fatigue degradation law of structural members is discussed. The prediction model is established for the evolution of mid-span deflection, concrete strain, reinforcement strain and residual ultimate bearing capacity with the fatigue loading times, respectively. The limit values of deflection, strain and residual bearing capacity under fatigue load are discussed, and a more accurate method for predicting the remaining service life of the structure is put forward. Based on the method of establishing the benchmark model, the finite element analysis model of Baihe Bridge of Jingmi Highway is established. Based on the investigation data of actual load, a fatigue vehicle model is established. Considering the rule of corrosion of steel bars and time-varying traffic volume, the fatigue performance of bridges in service life under the condition of overload, corrosion of steel bars and fatigue is studied. The life span is predicted.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U441.4

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