无背索双斜塔斜拉桥静力和整体稳定性分析

发布时间：2018-05-05 14:00

本文选题：无背索斜拉桥 + 有限元　；参考：《合肥工业大学》2017年硕士论文

【摘要】：无背索斜拉桥具有结构新颖、造型优美的特点。但是无背索斜拉桥特殊的结构形式,导致其空间受力状态与常规斜拉桥有很大不同,倾斜桥塔的稳定性要求比较高。本文以六安寿春西路无背索斜拉桥为工程背景,借助有限元方法,根据设计图纸来建立有限元模型,分析无背索双斜塔斜拉桥的结构受力行为、稳定性和极限承载力,从整体上把握桥梁的极限承载力和失稳行为,可为同类型桥梁的设计与施工提供参考。论文的主要工作内容包括:1.建立了寿春西路无背索斜拉桥有限元杆系单元模型,进行了静力分析和参数影响分析。结果表明,在设计张拉索力下,主梁抗弯刚度较大,主梁的跨中挠度值较小,但塔顶的位移相比于主梁位移比较明显,这是由于无背索斜拉桥的桥塔是倾斜的,如果拉索拉力不够大,在自重作用下会发生较大位移。所以在拉索强度和塔根部混凝土强度满足设计规范的要求下,成桥阶段应尽可能的增大张拉索力的大小。2.建立了寿春西路无背索斜拉桥有限元板壳实体单元模型,并与杆系单元模型进行了比较。实体建模非常复杂,而且计算量很大。计算结果偏于保守,但是可以更好地模拟关键部位的局部力学行为。因此对于大型的桥梁结构,一般可建立梁单元的整体模型,在需要更准确的考虑局部地区的破坏行为时,有必要建立板壳实体单元建立局部模型进行局部分析。3.采用寿春西路无背索斜拉桥有限元杆系单元模型,进行了自重作用下的弹性稳定性分析。结果发现,首先发生的是主塔横向弯曲失稳,屈曲系数是6.79,表明寿春西路桥的整体弹性稳定性较好。若只考虑一阶弹性失稳的情况下,主塔和副塔的两个塔柱不需要固结,寿春西路桥的结构稳定性在铰接的情况下仍然满足要求。4.采用寿春西路无背索斜拉桥有限元杆系单元模型,进行了非线性稳定分析和非线性因素影响分析。结果表明,几何非线性对该桥的极限承载力影响不大,但材料非线性影响很大,是全桥极限承载力的控制因素。在初始张拉索力下,寿春西路桥极限承载时的破坏路径是钢箱梁先发生屈服破坏,此时索力尚未达到极限状态。
[Abstract]:The cable-stayed bridge without back cable has the characteristic of novel structure and beautiful shape. However, the special structural form of cable-stayed bridge without back cable leads to a great difference between the spatial stress state and the conventional cable-stayed bridge, and the stability of inclined tower is very high. In this paper, based on the engineering background of Liu'an Shouchun West Road cable-stayed bridge without back cable, the finite element model is established according to the design drawing by means of finite element method, and the structural behavior, stability and ultimate bearing capacity of the cable-stayed bridge with double inclined tower without back cable are analyzed. To grasp the ultimate bearing capacity and unstable behavior of the bridge as a whole can provide a reference for the design and construction of the same type of bridge. The main work of the thesis includes 1: 1. The finite element element model of the cable stayed bridge with no back cable on Shouchun West Road is established, and the static analysis and parameter influence analysis are carried out. The results show that the flexural stiffness of the main beam is larger and the deflection of the main beam is smaller than that of the main beam, but the displacement of the tower top is more obvious than that of the main beam, which is because the tower of the cable-stayed bridge without back cable is inclined. If the cable tension is not large enough, a large displacement will occur under the action of self-gravity. Therefore, the cable strength and the concrete strength at the root of the tower meet the requirements of the design code, the bridge stage should be as much as possible to increase the size of tension. 2. The finite element model of plate and shell of Shouchun Xilu cable-stayed bridge without back cable is established and compared with the element model of bar system. Solid modeling is very complex and computationally expensive. The calculated results are conservative, but can better simulate the local mechanical behavior of the key sites. Therefore, for large bridge structure, the integral model of beam element can be established generally. When the failure behavior of local area needs to be considered more accurately, it is necessary to establish a local model of plate and shell entity element for local analysis. Based on the finite element model of the cable stayed bridge with no back cable in Shouchun West Road, the elastic stability of the cable-stayed bridge under deadweight is analyzed. The results show that the lateral buckling instability of the main tower occurs first, and the buckling coefficient is 6.79, which indicates that the overall elastic stability of Shouchun West Road Bridge is better. If only the first order elastic instability is considered, the two tower columns of the main tower and the secondary tower do not need to be consolidated, and the structural stability of the Shouchun West Road Bridge still meets the requirement of .4in the case of hinge connection. The nonlinear stability analysis and the influence of nonlinear factors are carried out by using the finite element model of the cable stayed bridge with no back cable in Shouchun West Road. The results show that the geometric nonlinearity has little effect on the ultimate bearing capacity of the bridge, but the material nonlinearity has a great influence on the ultimate bearing capacity of the bridge, which is the controlling factor of the ultimate bearing capacity of the whole bridge. Under the initial tension, the failure path of Shouchun West Road Bridge is the yield failure of the steel box girder, and the cable force has not reached the limit state.
【学位授予单位】：合肥工业大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U448.27

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