【作者】 兰枢灵；

【导师】 周绪红； 狄谨；

【作者基本信息】 长安大学 ， 桥梁与隧道工程， 2011， 硕士

【摘要】 薄壁钢箱梁有着优越的抗弯、抗扭和抗剪等受力性能,目前被广泛应用于大跨度斜拉桥、悬索桥及拱桥中。薄壁钢箱梁受力复杂,一些经典的计算方法已不适合对薄壁钢箱梁进行分析,而且关于薄壁钢箱梁结构的计算方法在我国公路桥涵钢结构设计规范还没有相关计算规定和公式,因此有必要对关于薄壁钢箱梁结构的计算方法进行讨论,从而更好的为同类结构的设计提供一些理论参考。回顾了国内外薄壁钢箱梁的发展进程,对箱梁计算方法进行了综述分析,得出对于宽跨比较大的桥梁采用梁格法模拟,能够得到结构的整体受力性能。为了验证梁格法分析宽跨比较大桥梁结构计算结果的可靠性与准确性,分别建立某钢箱梁桥的单主梁、梁格及板壳单元模型,对比了相同工况下三种模型的位移、应力以及内力。分析结果表明,对于宽箱梁桥,梁格法计算的挠度、应力与板壳单元吻合良好,内力与单梁法能够精确吻合。证明了梁格法模拟薄壁钢箱梁桥的准确性和可靠性。将梁格法应用于斜拉桥整体受力分析中,综合考虑结构形式、荷载状况、边界条件等特点,运用有限元软件MIDAS/Civil建立斜拉桥梁格有限元模型,分析了运营阶段分项活载及恒载和活载组合作用下结构的效应,得出该桥在正常使用极限状态下应力、挠度均满足规范要求。表明用梁格法进行钢箱梁斜拉桥计算分析是有效的。用通用的大型有限元计算软件ANSYS建立斜拉桥空间杆系有限元模型,并建立了混合有限元模型以及钢桥面板空间结构有限元模型,对相同工况下的箱梁截面顶板应力分别采用传统应力叠加法、全桥整体受力分析法和节段有限元法三种方法进行了计算,并对计算结果比较分析,表明全桥整体受力分析法计算准确,适合用来进行钢箱梁的计算。分别采用A.I.S.C规范中的方法和有限元法对钢桥面板第三结构体系应力进行了计算,通过对计算结果的比较分析表明,两者的横向应力基本相同,但纵向应力差很多。尽管有限元法能较准确有效的模拟实际结构,但第二、第三体系应力很难分开。在现行的钢桥面体系划分下,采用有限元法也会产生一定的误差。更多还原

【Abstract】 The thin-walled steel box girder had numerous advantages, such as good torsional stiffness, lateral bending stiffness, excellent wind resistance, etc. Therefore, it has been widely used in long-span cable-stayed bridges, suspension bridges, as well as arch bridges at present. This feature incurs that the behavior of thin walled steel box girder is too complex to be analyzed with classical calculational methods. No domestic criterions has prescripted a proximate calculational method available for this structure. It is useful to discuss the calculational methods of thin walled steel box girder, in terms of both theory and practice.A brief history of the development of thin walled steel bod girder structure in bridge engineering is reviewed. The anthor summarized the the calculational methods of thin walled box girder. For the big rate of width and span bridge,using grillage method can be simulated, and getting the whole structure of work performance.In order to investigate the feasibility and accuracy of grillage analogy method to the wide box grider, the single grider model, the grillage model as well as the shell element model are established, and the stress, displacement, shearing force, bending moment, torquemoment results from the three models are compared. The analytical results show that comparring with the single grider method, the results form the grillage analogy method are in good agreement with he shell element method and suitable for precisely describing the mechanical properties of the wide box grider, and the normal results from grillage analogy method are acceptable from an engineering design standpoint.The thesis building up the integrated finite element model of a cable-stayed bridge by the grillage simulation, considering the bridge structure,loading conditions, boundary conditions, etc. In the operational stage, the effect of the structure under combined live load and dead load is studied and analyzed, validating the stress and displacement of this bridge to the standard in the limit state. Using grillage method to analyze cable-stayed bridge is effective.With the general used finite element analysis software ANSYS,the spacial pole system finite element model,the mixing finite element model and segment finite element model were created to analyse the steel bix girder. Compared with segment finite element analysis method, and the stress superposition method, the whole structure analysis finite element method was sugguested to calculate thin walled steel box girder, because it is accurate. Using A.I.S.C. method and finite element method to study the third essential structure system respectively. By comparing the result of the two methods, it is easy to find that the calculation results are in a great difference at longitudinal. However the maximal transverse stress of the third essential structure system from A.I.S.C.method is quite close to the result of finite element method. Because of it’s results include the stress of the second system partly, the results are not precise, though the finite element method can simulate the virtual structure.更多还原