中下承式拱桥吊杆破断动力响应分析

发布时间：2018-03-09 15:39

本文选题：中下承式拱桥　切入点：吊杆　出处：《郑州大学》2017年硕士论文　论文类型：学位论文

【摘要】：中下承式拱桥得益于自身受力合理、造型美观等特点,近些年得到了极大的发展。而吊杆作为连接拱肋和桥道系的关键构件,将桥道系所承受的恒载、活载传递到拱肋上,为中下承式拱桥主要的承重构件。与桥道系和拱肋相比,吊杆更易受到疲劳或腐蚀的破坏,吊杆出现问题,情况严重时可导致桥道系的垮塌,在一定程度上决定了中下承式拱桥的安全与寿命。本文针对吊杆发生破断对桥梁结构产生的动力响应进行研究,以郑州刘江黄河大桥为工程背景,运用ANSYS有限元软件,建立郑州刘江黄河大桥标准跨精细梁单元模型,研究了单根吊杆破断和多根吊杆连续破断时结构的动力响应,并且与静力方法计算结果进行对比。论文主要研究内容和所得结论如下:(1)采用ANSYS有限元软件,建立了郑州刘江黄河大桥标准跨的空间有限元计算模型,利用计算得出的吊杆成桥索力值与设计图纸给出的设计值进行对比,来验证有限元模型的正确性。(2)对比分析了两种模拟吊杆破断方法的优劣,确定本文采用的模拟方法。根据最不利荷载的原则选取破断吊杆,确定模拟过程中的阻尼矩阵,确定吊杆破断时间,分别以短吊杆破断和长吊杆破断两种工况对结构的动力响应进行研究。(3)吊杆发生破断对桥道系的影响要大于对拱肋的影响,并且随着距离吊杆破断位置的增加,影响逐渐减小;吊杆发生连续破断时,会造成相邻吊杆内力的急剧增大,若吊杆安全系数设置过小,极有可能造成剩余吊杆接连破断,导致桥道系的垮塌。(4)对比吊杆破断时动力分析结果与静力分析结果可以看出,静力方法计算得出的桥梁力学性能与动力分析得出的桥梁力学性能有很大的差异,在实际工程中,不能直接用静力分析方法来替代吊杆破断动力分析方法。
[Abstract]:The middle through arch bridge has been greatly developed in recent years because of its reasonable force and beautiful shape. As a key member of connecting arch rib and bridge track system, the suspender transfers the dead load to the arch rib from dead load to the arch rib. It is the main load-bearing member of the middle through arch bridge. Compared with the bridge track system and arch rib, the suspension rod is more easily damaged by fatigue or corrosion, and the suspension rod has problems, which can lead to the collapse of the bridge track system when the condition is serious. To a certain extent, the safety and life of the through arch bridge are determined. In this paper, the dynamic response of the bridge structure caused by the break of the suspension rod is studied. Taking the Yellow River Bridge of Liu Jiang in Zhengzhou as the engineering background, the finite element software ANSYS is used. The standard span fine beam element model of Liu Jiang Yellow River Bridge in Zhengzhou is established, and the dynamic response of the structure under the condition of single suspender breaking and continuous breaking of multiple suspenders is studied. The main contents and conclusions are as follows: (1) using ANSYS finite element software, the spatial finite element model of the standard span of Liu Jiang Yellow River Bridge in Zhengzhou is established. In order to verify the correctness of the finite element model, the cable force of the suspension rod bridge is compared with the design value given in the design drawing, and the advantages and disadvantages of the two simulated suspender breaking methods are compared and analyzed. According to the principle of the most unfavorable load, the broken suspenders are selected, the damping matrix in the simulation process is determined, and the breaking time of the suspenders is determined. The dynamic response of the structure is studied under the two working conditions of short and long suspenders, respectively.) the influence of the breakage of the suspender on the bridge track system is greater than that on the arch rib, and the influence decreases gradually with the increase of the distance from the broken position of the suspender. If the safety factor of the suspension rod is set too small, it is very likely to cause the residual boom to break continuously, when the suspension rod breaks continuously, which will result in the sharp increase of the internal force of the adjacent suspenders, if the safety factor of the suspenders is set too small, Comparing the dynamic analysis results with the static analysis results when the suspenders break, it can be seen that the mechanical properties of the bridges calculated by the static method are quite different from the mechanical properties of the bridges obtained by the dynamic analysis. The static analysis method can not be directly used to replace the dynamic analysis method of boom breaking.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U448.22

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