【作者】 李平利；

【导师】 强士中；

【作者基本信息】 西南交通大学 ， 桥梁与隧道工程， 2004， 硕士

【摘要】 本文的主要内容是大跨度斜拉桥的静力几何非线性计算分析。首先介绍了斜拉桥几何非线性分析的基本理论，然后阐述影响斜拉桥几何非线性的三个主要因素：大位移、斜拉索垂度效应和弯矩与轴力的组合作用并分别介绍了这三种非线性影响因素的有限元分析方法；接着采用大型通用软件ANSYS针对南京三桥独塔斜拉桥方案建立有限元模型，详细说明了在建模过程中如何准确地模拟桥梁结构的真实受力情况和用软件ANSYS计算施工阶段时如何处理斜拉索的分段张拉、斜拉索垂度效应、单元的架设与拆除。最后对施工阶段的所有工况分别进行线性与非线性计算并对结果进行比较分析得出几点结论： (1) 非线性对主梁弯矩的影响以大位移与斜拉索垂度的影响最大，弯矩与轴力组合效应影响最小，而且不同的施工阶段影响程度也不同。 (2)．边跨合龙阶段与拆除吊机阶段对非线性的影响非常小，在这几个工况可以不考虑非线性的影响。 (3) 桥面系施工阶段非线性对主梁部分节点的弯矩影响较大，为18.2％，但是对主塔根部的弯矩影响较小，不到4％；塔顶水平位移非线性结果与线性计算结果比较出现了最大值7.2％，都是大位移与垂度效应的影响最大。 (4) 体系转换(拆除塔梁的固结约束)和拆除临时墩时非线性对塔根部的弯矩影响很大。计算的比较结果中，体系转换时非线性因素对塔根部的弯矩影响达到了67.8％，拆除临时墩时非线性因素对塔根部弯矩的影响达到了35％。其中大位移对塔根部弯矩的影响最大。 (5) 主梁的竖向位移的比较，右跨跨中在结构体系转换(拆除塔梁固结约束)以前相差最大，大位移和垂度效应影响下主梁竖向位移相差比值达到了17％左右。以后的工况中，大位移和垂度效应影响下主梁竖向位移相差最大，为8.3％。更多还原

【Abstract】 This thesis focuses on geometric nonlinear static analysis of long-span cable-stayed bridges. Firstly, the basic theory of geometric nonlinear analysis for long-span cable-stayed bridge is introduced. Then three principle factors that affect geometric nonlinearity of cable-stayed bridges are described, which are large displacement, effect of cable sag and combined effects of moment and axial force; then the finite element methods are introduced separately. And then, the finite element model of Nanjing Third Bridge according to its scheme of cable-stayed bridge with single pylon is erected by ANSYS, a general finite element software. After that the thesis presents detailedly the dealing methods to simulate the real load-bearing condition of bridge structure and how to deal segmentary strengthing of cable, effects of cable sag and erecting and removing of element under construction phase. At last, the linear and nonlinear analysis to all load cases under construction stage are made. According to the comparison between those results, conclusions are drew as. followed:(1) Nonlinearity of large displacement and cable sag has thelargest effect on the moment of main girder, while the combined effect of moment and axial force has the least effect. What’s more, the effect degree is different in different construction phases.(2) Closure construction of side spans and the remove of crane have very little effect on nonlinearity, so effects of nonlinearity can not be considered in these load cases.(3) Nonlinearity in construction stage of deck system has a bigger effect by 18.2% on part nodes of main girder but no more than 4% on the end of main girder. The maximum value 7.2% occurs in comparison between nonlinear results and linear results of horizontally displacements on top of tower, in which large displacement and sag effects are main factors.(4) Nonlinearity of system transformation(removing fixed constraints of tower beam) and remove of temporary pier has a great effect on the end of tower. In the comparison between the results, the effect of nonlinear factors in system transformation on the moment of end of tower reaches by 67.8%, and the effect of nonlinear factors in remove of temporary pier on the moment of end of tower reaches by 35%. Among these factors, large displacement has the largest effect on the moment of end of tower.(5) In comparison of vertical displacement of main girder, the difference in midspan of right span before system transformation(removing fixed constraints of tower beam) is the largest. The differential ratio of vertical displacement of main girder under the effects of large displacement and sag effects reaches by 17% around. Inother load cases, the largest differential ratio is 8.3%.更多还原