异形钢管混凝土系杆拱桥吊杆可靠度研究

发布时间：2018-03-31 17:34

本文选题：系杆拱桥　切入点：吊杆　出处：《东南大学》2015年硕士论文

【摘要】：我国自改革开放以来一直处于交通基础建设大力发展时期,大量桥梁需要建设,系杆拱桥在桥梁建设中备受青睐。尤其是近十几年来,我国修建了一大批大跨径的系杆拱桥。然而在快速建设过程中,不可避免存在一些安全性问题。吊杆作为系杆拱桥的重要的传力构件,能否正常工作关系到整个系杆拱桥的安全。近年来围绕吊杆失效发生了许多桥梁事故和大量的吊杆更换案例表明吊杆的可靠性研究是十分迫切和必要的。本文以瀛洲大桥为研究对象,在已有相关研究成果的基础上,研究了该桥在车流荷载作用的吊杆疲劳可靠度问题。主要研究过程和成果如下：(1)建立了瀛洲大桥的有限元模型,根据疲劳分析的需要,建模过程中对桥梁结构做了适当的简化。用模态试验和吊杆索力测试的结果与模型计算结果进行比较,验证了模型的精确性,结果表明该简化模型可以满足疲劳分析的精度需求。(2)对瀛洲大桥的交通流资料进行统计,获得该桥的荷载谱,采用蒙特卡罗方法建立瀛洲大桥的车流的数学模型,并使用MATLAB软件进行编程,完成实现交通流在计算机上的模拟,获得该桥的交通流加载数据。(3)将模拟的交通流加载通过程序接口加载到瀛洲大桥的有限元模型进行计算,从结果文件提取吊杆应力时程并采用雨流法循环计数。对垂直吊杆和斜吊杆分别在应力变化、应力幅变化和循环次数三个方面进行分析。分析结果表明,斜吊杆比垂直吊杆的受力更为不利,而且在相同的交通流荷载条件,应力幅循环次数因为吊杆的位置和布置方式而各不相同。(4)基于累积损伤理论推导出了可用于瀛洲桥吊杆可靠度计算方法,采用模拟等方法获得所需变量后,计算了吊杆有无腐蚀两种条件下的可靠度,根据计算结果得出主要结论为：斜吊杆的可靠度指标要低于垂直吊杆,且更早进入大概率失效；处于刚度变化位置的斜吊杆的可靠度指标最低,是需要重点关注的危险吊杆；腐蚀情况下吊杆的可靠度指标比未腐蚀的吊杆有明显的降幅,并且可靠度指标的下降速率腐蚀随着时间的延长而增大。(5)本文还根据威布尔分布概率理论给出了另一种吊杆疲劳可靠度的计算方法并采用该方法计算吊杆可靠度,结果表明该方法同样可以用来分析吊杆疲劳可靠性,虽然计算结果较为保守但是计算简便,仍不失为一种较好的分析方法。
[Abstract]:Since the reform and opening up, China has been in the period of development of transportation infrastructure construction, a large number of bridges need to be built, tied arch bridge is favored in bridge construction, especially in the past ten years, A large number of long-span tied arch bridges have been built in China. However, in the process of rapid construction, some safety problems inevitably exist. The safety of the whole tied arch bridge is related to the normal operation. In recent years, there have been many bridge accidents around the failure of the suspenders and a large number of cases of the replacement of the suspenders show that it is very urgent and necessary to study the reliability of the suspenders. Yingzhou Bridge is the object of study. On the basis of the related research results, the problem of the fatigue reliability of suspenders under vehicle flow loads is studied. The main research process and results are as follows: (1) the finite element model of Yingzhou Bridge is established, and according to the need of fatigue analysis, the finite element model of Yingzhou Bridge is established. In the process of modeling, the bridge structure is simplified properly. The accuracy of the model is verified by comparing the results of the modal test and the cable force test of the suspension rod with the calculated results of the model. The results show that the simplified model can satisfy the precision requirement of fatigue analysis. (2) the traffic flow data of Yingzhou Bridge are statistically analyzed, the load spectrum of the bridge is obtained, and the mathematical model of the traffic flow of Yingzhou Bridge is established by Monte Carlo method. The computer simulation of traffic flow is accomplished by using MATLAB software. The traffic flow loading data of the bridge is obtained. The simulated traffic flow loading is loaded into the finite element model of Yingzhou Bridge through the program interface. The stress time history of the suspender is extracted from the result file and the rain flow method is used to calculate the stress. The variation of stress, the amplitude of stress and the number of cycles of the vertical and oblique suspenders are analyzed respectively. The results show that, Oblique suspenders are more unfavorable than vertical suspenders, and under the same traffic flow load conditions, The cyclic times of stress amplitude are different from each other because of the position and arrangement of the suspenders. (4) based on the cumulative damage theory, the reliability calculation method for the suspenders of Yingzhou Bridge is derived, and the required variables are obtained by means of simulation and other methods. The reliability of the suspension rod with or without corrosion is calculated. The main conclusions are as follows: the reliability index of the inclined suspension rod is lower than that of the vertical suspension rod, and the failure rate of the slant boom is higher than that of the vertical suspension rod; In the position of stiffness change, the reliability index of inclined suspender is the lowest, which needs to be paid more attention to, and the reliability index of suspender under corrosion condition is obviously lower than that of uncorroded suspender. And the decreasing rate corrosion of reliability index increases with the extension of time. In this paper, according to the probability theory of Weibull distribution, another method of calculating the fatigue reliability of suspenders is given and the reliability of suspenders is calculated by this method. The results show that this method can also be used to analyze the fatigue reliability of the boom. Although the calculation results are conservative but the calculation is simple, it is still a good analysis method.
【学位授予单位】：东南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U448.225

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