大跨度悬索桥双层正交异性板钢桁加劲梁扭转行为研究

发布时间：2018-03-30 21:08

本文选题：扭转荷载　切入点：模型试验　出处：《西南交通大学》2017年硕士论文

【摘要】：悬索桥由于其良好的跨越能力、优美的结构造型、明确的受力体系,在大跨桥领域扮演着越来越重要的角色。本文针对悬索桥中的双层板桁结合桥面桁梁加劲梁的扭转行为进行研究,主要的内容和结论有如下:一、对于双层板桁结合桥面桁梁加劲梁,采用模型试验的方法,选取一个节段,针对该节段进行偏心荷载作用下变形行为的研究,并建立了与试验模型一致的有限元模型,模拟试验过程,与试验结果进行比对,最后发现该结构在偏心荷载作用下,横截面不仅会出现刚性扭转,而且会发生较显著的剪切变形。二、推导板桁结合桥面桁梁在扭转荷载作用下的响应计算方法。采用刚度等效的原则将其连续等效化为薄壁箱梁,并根据其在扭转荷载作用下是否只发生刚性扭转分成了横截面可变形和不可变形两种情况进行分析。对于在扭转荷载作用下横截面只发生刚性扭转的情况,应用闭口截面薄壁杆件乌曼斯基约束扭转理论,获得关于扭转变形的微分方程。对于横截面可变形的扭转,将横截面的变形看作是刚性扭转和剪切变形的叠加,而扭转荷载分解为纯扭矩荷载和双向反力偶荷载,最后获得关于横截面扭转变形和剪切变形的微分方程组。选取杨泗港长江大桥的加劲梁,运用解析法与有限元法对结构在扭转荷载下的响应进行求解,并对比计算结果,发现求解效果良好。三、将前面获得的加劲梁扭转效应计算方法推广到悬索桥在竖向偏心荷载作用下变形响应的计算。采用经典的挠度理论,获得了悬索桥加劲梁在偏心荷载作用下,关于加劲梁扭转响应的微分方程组,并介绍了微分方程组的求解方法以及步骤,以杨泗港长江大桥为例,分别采用挠度理论和有限元方法进行求解,在计算加劲梁扭转变形方面,挠度理论与有限元法的计算结果吻合度较高。
[Abstract]:The suspension bridge, due to its good span ability, graceful structural shape, clear force system, In this paper, the torsional behavior of stiffened beam with double deck truss in suspension bridge is studied. The main contents and conclusions are as follows: 1. For the stiffened beam of double-deck truss beam combined with bridge deck, a segment is selected by model test, and the deformation behavior of the section under eccentric load is studied, and a finite element model consistent with the experimental model is established. Compared with the experimental results, it is found that the cross section of the structure will not only appear rigid torsion, but also have obvious shear deformation under eccentric load. The method of calculating the response of slab truss combined with bridge deck truss under torsional load is deduced. The principle of stiffness equivalence is adopted to convert the continuous equivalent to thin-walled box girder. According to whether there is only rigid torsion under torsional load, it is divided into two cases: transversal deformable and non-deformable. For the case that only rigid torsion occurs under torsional load, The differential equation of torsional deformation is obtained by using the Wumansky constrained torsion theory for thin-walled bars with closed section. For the deformable torsion of cross-section, the deformation of cross-section is regarded as the superposition of rigid torsion and shearing deformation. The torsional load is decomposed into pure torque load and bidirectional countercouple load. Finally, the differential equations about torsional deformation and shear deformation of cross section are obtained. The stiffened beam of Yangsigang Yangtze River Bridge is selected. The analytical method and finite element method are used to solve the response of the structure under torsional load, and the results are compared and the results are found to be good. The calculation method of torsional effect of stiffened beam is extended to the calculation of deformation response of suspension bridge under vertical eccentric load. The classical deflection theory is used to obtain the stiffening beam of suspension bridge under eccentric load. In this paper, the differential equations of torsional response of stiffened beam are introduced, and the solving methods and steps of the differential equations are introduced. Taking Yangsigang Yangtze River Bridge as an example, the deflection theory and finite element method are used to solve the problem, respectively. In the calculation of torsional deformation of stiffened beam, the deflection theory is in good agreement with the result of finite element method.
【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】：U448.25

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