大跨自锚式悬索桥运营安全分析研究

发布时间：2019-01-30 14:31

【摘要】：大跨自锚式悬索桥属于柔性缆索体系悬索桥的一种。吊索作为自锚式悬索桥的主要传力构件，其安全性与耐久性关系到整个桥梁结构的运营安全，，吊索损坏可能会严重影响桥梁结构的安全；此外，钢箱梁的桥面铺装厚度、环境温度变化以及车辆超载等对大跨度自锚式悬索桥的运营安全的影响也不容忽视。本文以桃花峪黄河大桥双塔三跨自锚式悬索桥为背景，对大跨自锚式悬索桥的运营安全进行研究分析，主要工作内容和结论如下： 1．总结了自锚式悬索桥的结构体系，受力特点，对自锚式悬索桥的合理成桥状态、吊索破损的模拟方法、桥梁铺装、温度作用以及车辆超载的研究现状进行综述。 2．利用Midas/Civil软件建立桃花峪黄河大桥的全桥有限元模型，根据先化整为零，组合成桥的分步方法确定成桥索力，然后计算主缆的几何线形和吊索的无应力长度，并得到该桥的合理成桥状态。 3．在合理成桥状态的基础上，采用静力法对吊索断裂进行模拟对比分析，在已有理论的基础上，以钢结构达到屈服强度或者剩余吊索的最大拉应力达到材料容许拉应力作为结构发生破坏的评判准则，选择不同位置，不同吊索发生断裂的工况，对桥梁结构的安全影响进行分析，通过分析可得出单根吊索发生断裂时，桥梁结构的静力性能影响有限，当连续出现两根或者三根吊索断裂时，会影响桥梁的主体结构，增加桥梁修复的难度，特别是应对桥梁跨中附近的短吊索和断裂吊索附近相邻的吊索加强防护。 4．在成桥状态的基础上，考虑钢箱梁桥面铺装施工中的偏差，通过改变铺装层的厚度和位置来模拟桥面铺装层的不均匀，分析钢箱梁桥面铺装不均匀时对自锚式悬索桥结构后期运营的影响。分析可得，桥面铺装层厚度的增加与主梁位移变化成正比例，对吊索受力变化影响很小，对桥梁整体受力及运营安全影响有限。 5．在成桥状态的基础上，按照设计规范中温度荷载的规定，对结构进行整体升降温和温度梯度分析，分析自锚式悬索桥结构索力变化和位移变化，并对整体结构安全进行分析。得出整体升降温对自锚式悬索桥的影响不大，顶底板的温差的影响比较显著，日温的变化对钢箱梁影响较大。 6．在成桥状态的基础上，分析车辆超载对自锚式悬索桥结构的影响，为桥梁的运营安全提供理论依据。随着超载系数的增大，主梁最大竖向位移和主缆应力不断增加，计算出的主梁的超载安全度为2.04，主缆的超载安全度为1.32。车辆超载对自锚式悬索桥结构的运营安全有很大影响。
[Abstract]:Long span self-anchored suspension bridge belongs to the flexible cable system suspension bridge. As the main force transfer component of self-anchored suspension bridge, the safety and durability of the sling are related to the operation safety of the whole bridge structure, and the damage of the slings may seriously affect the safety of the bridge structure. In addition, the influence of deck pavement thickness, ambient temperature change and vehicle overload on the operation safety of long-span self-anchored suspension bridge can not be ignored. Based on the two-tower and three-span self-anchored suspension bridge of Taohuayu Yellow River Bridge, the operation safety of long-span self-anchored suspension bridge is studied and analyzed in this paper. The main contents and conclusions are as follows: 1. The structure system of self-anchored suspension bridge is summarized. In this paper, the reasonable state of self-anchored suspension bridge, the simulation method of sling breakage, the bridge pavement, the effect of temperature and the overloading of vehicle are summarized. 2. The finite element model of the whole bridge of Taohuayu Yellow River Bridge is established by using Midas/Civil software. The cable force of the bridge is determined by the stepwise method of combining the bridge, and then the geometric alignment of the main cable and the stress free length of the sling are calculated. The reasonable state of the bridge is obtained. 3. On the basis of the reasonable state of the bridge, the static method is used to simulate and analyze the sling fracture, and on the basis of the existing theories, When the steel structure reaches yield strength or the maximum tensile stress of the remaining sling reaches the material allowable tensile stress is taken as the criterion for judging the failure of the structure, and the failure conditions of different slings are chosen at different locations. Through the analysis of the safety effect of bridge structure, it can be concluded that the static energy of bridge structure is limited when a single sling is broken, and the main structure of the bridge will be affected when two or three sling cables break continuously. It is difficult to repair the bridge, especially to strengthen the protection of the short slings near the middle span of the bridge and the adjacent slings near the broken slings. 4. On the basis of the state of the bridge, considering the deviation in the bridge deck pavement construction of steel box girder, by changing the thickness and position of the pavement layer, the non-uniformity of the bridge deck pavement can be simulated. The influence of uneven deck paving of steel box girder on the late operation of self-anchored suspension bridge is analyzed. It can be concluded that the increase of bridge deck pavement thickness is in direct proportion to the displacement of the main beam and has little effect on the stress change of the slings and limited influence on the overall force and operation safety of the bridge. 5. On the basis of the state of the completed bridge, according to the temperature load stipulated in the design code, the integral lifting and temperature gradient analysis of the structure is carried out, and the variation of the cable force and displacement of the self-anchored suspension bridge structure is analyzed. The safety of the whole structure is analyzed. It is concluded that the whole rise and cooling has little effect on the self-anchored suspension bridge, the effect of the temperature difference on the top and bottom plate is obvious, and the change of the daily temperature has a great influence on the steel box girder. 6. The influence of vehicle overload on the structure of self-anchored suspension bridge is analyzed on the basis of the state of the completed bridge, which provides the theoretical basis for the operation safety of the bridge. With the increase of the overload coefficient, the maximum vertical displacement and the stress of the main cable increase continuously. The calculated overloading safety degree of the main beam is 2.04 and the overloading safety degree of the main cable is 1.32. Vehicle overload has great influence on the operation safety of self-anchored suspension bridge.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U448.25

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