澳凼三桥稳定的分析.pdf

了577523 摘要近年来斜拉桥在国内外得到了迅速发展,不但修建数量急剧增加,跨度不断增大, 而且根据建桥地点的环境和自然条件,斜拉桥的类型也日臻完善。斜拉桥是一种比较细柔的结构,在外荷载作用下,索塔承受了很大的压力,当压力达到一定值时康塔就可能产生较大的屈曲变形,进而丧失稳定性。澳幽三桥结构体系属部分斜拉桥,又称矮塔斜拉桥,结构受力兼有斜拉桥和体外布束连续梁的性质。主塔以偏心受压为主, 主梁以压弯为主。由于结构功能的需要,主梁截面较大,主塔截面相对薄弱。故须对结构进行稳定分析。桥梁稳定分析的目标为确定结构在使用荷载作用下的稳定安全系数。本文利用有限元方法并利用ANSYS这一工具来达到此目的。这种方法近似把结构当成理想弹性材料,并利用第一类稳定问题求特征值的思路来求解。本文针对澳幽三桥的特征分别对主塔进行了整体稳定分析和主梁进行了局部稳定分析,具体分析了施工、运营两个工作阶段、六种荷载工况及塔梁相交处不同边界条件下的结构稳定。指出该桥在预期荷载作用下,结构的整体失稳首先发生于桥塔,主梁局部失稳首先发生于梁顶板,塔梁相交处不同边界条件对其稳定安全影响很大。为了验证分析结果,作者在有限元理论的基础上用FORTRAN语言编写了可以求桥梁结构稳定安全系数的计算软件,经与ANSYS结果进行对比,表明两者相差很小。本文的研究结果,对澳由三桥的设计和施工具有指导意义。关键词:有限元斜拉桥稳定性、、导纤i愈公布 Abstract With the fast development of cable stayed bridges in the world, the number o# cable stayed bridges has increased and the span of them has been broaden. Moreover,the type of them has been improved according to the surrounding where they are built. A cable stayed bridge is a slim structure, which bears big compressional stress caused by loads. When pressional stress reaches one extent, the pylor will tranform in terms of buckling and lose stability. The Macau-Taipa 3rd bridge is a part-bridge, whose main pylor pressional stress and main girder bears compressional stress and moments. Relatively, the main girder's section is larger than the pylor's, so the pylor's whole stability should be checked. The aim of buckling analysis is to work out the safety factor of stability, which will be obtained by FE and ANSYS in the study in my graduation procedure discusses the stability by linear methods and 1st stability model. In this paper, eigenvalue buckling analysis of Macao-Taipa 3rd Bridge is performed by being classified into two work stage and six load cases with global and local FE models. Two kinds of boundary conditions of girder at crossing area of towers and girders are als