斜拉桥Ⅱ形主梁剪力滞效应分析

发布时间：2018-03-02 15:55

本文选题：Π形主梁　切入点：剪力滞　出处：《广西大学》2014年硕士论文　论文类型：学位论文

【摘要】：本文基于剪力滞效应的分析理论,结合Reissner能量变分法的原理,假定翼板的纵向位移为四次抛物线形式,对n形主梁的剪力滞效应进行了理论研究,推导了不同边界条件下的剪力滞效应计算公式。从研究结果中可知,边界条件、荷载形式、主梁截面、主梁宽度等会对n形主梁的剪力滞效应产生一定的影响。为了探究斜拉桥∏形主梁在施工与成桥阶段的剪力滞效应,以对斜拉桥∏形主梁的施工与监控提供有效的参考意见,本文根据有限单元法的基本理论,利用有限元程序MIDAS建立了本文依托工程——针鱼岭大桥的有限元模型,分析了其分布规律。从分析结果可以看出,任一块主梁施工完成后,除了0号块与该块主梁及其附近梁段,中间梁段的剪力滞效应变化平缓；成桥阶段的剪力滞系数比施工阶段较小,其剪力滞分布规律变化不大；不论施工阶段与成桥阶段均有负剪力滞现象出现。根据文中对n形主梁剪力滞效应的理论分析结果,为了对斜拉桥n形主梁的优化设计提供依据,本文利用有限单元法研究了翼板的悬臂板长度与翼板厚度对斜拉桥∏形主梁的剪力滞影响。结果显示,随着翼板的悬臂板长度的增加,对剪力滞效应的纵向分布影响不大,并且除了主梁末端及其附近梁段,其他梁段的剪力滞系数沿横向均在减小；随着翼板厚度的增加,对剪力滞效应的纵横向分布影响均比较明显。
[Abstract]:Based on the analysis theory of shear lag effect and the principle of Reissner energy variational method, the longitudinal displacement of airfoil is assumed to be a fourth parabola form, and the shear lag effect of n-shaped main beam is studied theoretically in this paper. The formulas for calculating shear lag effect under different boundary conditions are derived. From the results of the study, it can be seen that boundary conditions, load forms, main beam section and beam width will have certain influence on the shear lag effect of n-shaped main beam. In order to probe into the shear lag effect of the 蟺 shape main girder of cable-stayed bridge in the stage of construction and completion, and to provide an effective reference for the construction and monitoring of the 蟺 shape main girder of cable-stayed bridge, this paper is based on the basic theory of finite element method. By using finite element program MIDAS, the finite element model of this project-Jiyuling Bridge is established, and its distribution law is analyzed. It can be seen from the analysis result that after the construction of any main beam, except block 0 and the section of the main beam and its adjacent beam, The shear lag effect of the middle beam section changes slowly, the shear lag coefficient of the bridge stage is smaller than that of the construction stage, and the distribution law of the shear lag is not changed much; no matter the construction stage and the completion stage, the phenomenon of negative shear lag appears. According to the theoretical analysis results of shear lag effect of n-shaped main girder in this paper, in order to provide the basis for the optimum design of n-shaped main girder of cable-stayed bridge, In this paper, the effects of cantilever length and thickness of the wing plate on the shear lag of the girder of a cable-stayed bridge are studied by means of the finite element method. The results show that the longitudinal distribution of the shear lag effect is not affected by the length of the cantilever plate with the increase of the length of the cantilever plate. Besides the end of the main beam and its adjacent beam segment, the shear lag coefficient of other beam segments is decreasing along the transverse direction, and the longitudinal and horizontal distribution of shear lag effect is obvious with the increase of the thickness of the flange.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441.5

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