【作者】 谢维超；

【导师】 张开银；

【作者基本信息】 武汉理工大学 ， 结构工程， 2012， 硕士

【摘要】 斜拉桥作为一种由索、塔和梁组成的组合体系桥梁结构,以其跨越能力大,结构新颖而成为现代桥梁工程中发展最快、最具有竞争力的桥型之一。斜拉索是斜拉桥的重要组成部分,它承担了施工阶段和成桥后正常运营阶段的大部分荷载,索力合理与否直接决定了斜拉桥施工阶段结构的受力安全和成桥后结构内力的合理分布。因此,斜拉桥索力的优化对斜拉桥成桥后内力状态是否合理具有重要的影响作用。对于大跨径斜拉桥来说,其几何非线性的影响已经不能忽视。因此在索力的优化中也有必要考虑其影响。然而现有斜拉桥索力优化程序大多在线性条件优化得出索的初始拉力。虽然许多学者对斜拉桥的非线性索力做了大量研究,也取得了一定成果,但是其优化方法得出的是斜拉桥成桥后斜拉索的内力,并没有介绍如何得出拉索的初始拉力。本文在现有研究的基础上,围绕非线性下斜拉桥成桥状态合理初始索力的确定这一主题展开工作,归纳起来有以下几个方面：(1)分析了大跨径斜拉桥几何非线性的主要影响因素,包括斜拉索的垂度效应、弯矩与轴向力组合效应和大变形效应,同时对目前斜拉桥几何非线性问题的分析理论和研究水平进行了综述,相应讨论了各非线性影响因素的处理方法,即分别采用等效弹性模量法、引入稳定性函数和实时修正结构的几何位置。(2)斜拉桥索力的正确确定是实现合理成桥状态的首要任务,通过调整索力来改变结构的受力分配,对优化其受力尤其重要。本文回顾了国内外确定斜拉桥合理成桥索力方法的研究现状与发展水平,对斜拉桥成桥索力优化的现状作了初步的分析,并归纳出了斜拉桥优化的原则。(3)分析斜拉桥的三大几何非线性因素对斜拉桥拉索合理初始拉力的影响。在几何非线性的三大因素中,以斜拉索垂度效应影响最大,大位移效应次之,梁一柱效应影响最小。以郧阳汉江公路大桥为算例,利用Midas/Civil现有的线性优化功能,进行迭代求出其非线性下拉索的初始拉力。更多还原

【Abstract】 As a kind of flexible structure with great ability of span, cable-stayed bridge has quiet great progress in recent years. The cable is one of the key parts of cable-stayed bridge. It takes on most part of the Load in constructing and constructed of cable-stayed bridge. Rational cable force can guarantee the structure safety in construction and make the structure’s internal force reasonable after construction.Therefore; the cable force optimization of the cable-stayed bridge has important effect on internal force after construction whether reasonable.For long-span cable-stayed bridge, the geometric nonlinear effects can not be ignored. Therefore, the optimization of the cable force is necessary to consider its impact. However, the existing cable tension optimization program based on linear conditions obtain the initial cable tension. Although many scholars have done a lot of the nonlinear cable forces of cable-stayed bridge research, and achieved certain results, but its optimization method derived from the internal forces of cable-stayed Cable Stayed Bridge, and does not describe how you reached the initial tension of the cable.This paper based on the existing researches on cable-stayed bridge, centers around the calculate methods for rational cable force. Which can be summarized as follows:(1) Geometric nonlinear behaviors in large span cable-stayed bridges have been analyzed, which include the sag of inclined cable stays caused by their own dead weight; the interaction of large bending and axial deformation in bending members; and the large displacements effects. Then analyzing theories and researching levels of geometric nonlinear problems of modern cable-stayed bridges have summarized. And methods of modeling cable-stayed bridges for nonlinear finite element analysis have been discussed, which are the equivalent modulus of elasticity, introducing stability functions and continuously modifying geometry of structure. Then in this thesis some basic methods for geometric nonlinear analysis of cable-stayed bridges have also been discussed and algorithm of co-moving coordinate iteration combined incremental and iterative approach is established. (2) Cable-stayed bridge is to realize the correct cable force to determine reasonable bridge state priority, and through the adjustment to the stress of the structure change of cable force distribution, to optimize the force is especially important. At first the research results about cable force optimization both at home and abroad are reviewed, and then the present situation of cable force optimization is preliminarily analyzed, and the optimization principle of cable-stayed bridge is concluded in the paper.(3) Analysis of the cable-stayed bridge three geometric nonlinear factors on cable-stayed Bridges of reasonable initial tension influence. In the three factors of geometric nonlinearity, cable sag effect has the most obvious effect on the moment of main girder and nonlinear of large displacement has greater effect, while the combined effect of moment and axial force has the least influence. As Yuyang Hanjiang Highway Bridge for example, using the Midas/Civil existing linear optimization function iteration calculate the nonlinear of the cable-stayed under initial tension.更多还原