大跨度铁路斜拉桥锚拉板式索梁锚固区受力特性研究

发布时间：2019-02-22 19:42

【摘要】：斜拉桥的索梁锚固区作为联系斜拉索与主梁的重要部位,在长期荷载作用下存在传递荷载大、传力机理复杂、局部应力集中等问题。新建岳口汉江特大桥是国内少有的应用锚拉板式索梁锚固结构的铁路斜拉桥,其边腹板直接伸出顶板15cm,锚拉板结构直接与其对接焊接。本文基于汉江特大桥新型锚拉板结构,对其进行了全面深入的研究,主要的研究内容和成果如下:1、对锚拉板式索梁锚固区进行有限元仿真分析,通过多种单元组合的方法进行相互验证,最终确定锚拉板结构部分运用板壳单元与实体单元相结合的建模方式较为合理。2、对岳口汉江特大桥锚拉板式索梁锚固结构进行空间有限元分析,分析了在最不利索力作用下锚拉板式索梁锚固结构以及箱梁的应力大小以及分布规律特性;分析了锚拉板结构主要传力焊缝的应力变化趋势,提出了改善应力分布、减小应力集中现象的一些措施。3、根据应力等效原则,设计岳口汉江特大桥锚拉板式索梁锚固结构的试验模型,通过有限元分析计算,比较不同的设计方案,最终确定把方案三作为疲劳试验模型,并将试验模型锚拉板各板件的计算结果与原桥模型的锚拉板各板件计算结果做对比,确定疲劳试验模型的合理性与可行性。4、在仿真分析的基础上,进行锚拉板模型试验研究。由试验结果可知:锚拉板结构各主要板件的实测数据与有限元仿真分析结果吻合度较高,采用有限元数值分析对桥梁结构局部应力分析是行之有效的。在疲劳验证阶段,各测点均处于弹性工作状态,锚拉板结构没有出现裂纹;在疲劳破坏阶段,模型各测点测试值随荷载循环次数的增加也基本保持不变,模型各测点应力规律与疲劳验证阶段基本相同。最后通过对模型结构进行取样打磨观测并没有发现裂纹。因此,汉江特大桥锚拉板结构具有足够的疲劳强度储备。
[Abstract]:The anchoring zone of cable-beam of cable-stayed bridge is an important part of connecting cable with main beam. Under the action of long-term load, there are some problems such as large transfer load, complicated mechanism of transmission force, local stress concentration and so on. The newly built Yuekou Hanjiang River Bridge is a rare railway cable-stayed bridge with anchor plate type cable beam anchor structure in China. The side web of the bridge extends directly to the roof of 15 cm and the anchor plate structure is welded directly with the bridge. In this paper, based on the new type anchor plate structure of Hanjiang River Bridge, the main research contents and results are as follows: 1, finite element simulation analysis of anchoring area of anchor plate cable beam is carried out. The method of combination of various elements is used to verify each other. Finally, it is determined that the modeling method of the combination of plate and shell element and solid element is more reasonable in the structure part of anchor and pull plate. 2. The finite element analysis of the anchor plate cable beam Anchorage structure of the Yuekou Hanjiang River Bridge is carried out, and the stress size and distribution characteristics of the anchor plate cable beam under the action of the least effective cable force are analyzed. This paper analyzes the stress variation trend of the main force transfer weld of anchor and pull plate structure, and puts forward some measures to improve the stress distribution and reduce the stress concentration phenomenon. 3. According to the principle of stress equivalence, some measures are proposed to improve the stress distribution and reduce the stress concentration phenomenon. The test model of anchor plate type cable beam Anchorage structure of Hanjiang River Bridge in Yuekou is designed. Through finite element analysis and calculation, different design schemes are compared, and the third scheme is determined as fatigue test model. By comparing the calculation results of the test model with those of the original bridge model, the rationality and feasibility of the fatigue test model are determined. 4, on the basis of simulation analysis, The model test of anchor and pull plate was carried out. The experimental results show that the measured data of the main plates of the anchor plate structure are in good agreement with the results of the finite element simulation analysis, and it is effective to use the finite element numerical analysis to analyze the local stress of the bridge structure. At the stage of fatigue verification, each measuring point is in elastic working state, and no cracks appear in the anchor plate structure. In the fatigue failure stage, the measured values of each measuring point of the model also remain basically unchanged with the increase of the number of cycles of load, and the stress law of each measuring point of the model is basically the same as that of the fatigue verification stage. Finally, no cracks were found by sampling and grinding the model structure. Therefore, the Anchorage plate structure of Hanjiang River Bridge has enough fatigue strength reserve.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U448.27

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