钢管混凝土拱桥非线性稳定分析-桥梁与隧道工程专业论文.docxVIP

摘 摘 要 钢管混凝土拱桥在我国走过了十余年的发展历程，无论是其应用规模还是跨 径增长的速度都是惊人的。然而，钢管混凝土拱桥的计算理论还有许多问题有待 进一步的深入研究，我国交通行业的钢管混凝土拱桥设计规范也在制定之中· 根据目前对钢管混凝土构件力学性能的研究，本文在稳定分析中引入了钢管 混凝土构件的本构关系模型，以考虑材料非线性对稳定的影响。通过对模型的分 析，得出线弹性下结构的稳定安全系数明显偏大；几何非线性分析得出的结构稳 定安全系数与线弹性下的结果相差不大，几何非线性对钢管混凝土拱桥的稳定性 影响很小；而考虑双重非线性因素计算得出的临界荷载值明显要比线弹性分析和 几何非线性分析结果有较大下降。同时说明钢管混凝土拱桥的失稳大部分是发生 在弹塑性变形范围，即拱发生侧向届曲时结构的应力大于材料的弹性极限，按几 何非线性和材料非线性理论来求得拱桥的失稳极限荷载是拱桥的稳定荷载。 此外，就横撑的布置形式、主拱圈和桥面系剐度、吊杆的非保向力效应等因 素对该桥整体稳定性的影响展开探讨与研究，得出了以上因素对钢管混凝土此种 桥型稳定性影响的一般规律。 关键词：钢管混凝土，拱桥，非线性，稳定性 AbstractThe Abstract The devetopment history of the concrete-ffiled stecl tube(CFST)arch bridges is more than ten years in OUr country,we are all surprised to its application range or increase in span．However，the calculation theory of CFST arch bridges need to be 丘ll-ther lucubrated,the design criterion of CFST arch bridge is also being constituted． In order to consider the nonlinear behavior of material，the stress—strain relationship of concrete filled steel·tube structure is introduced in the following research．The analysis result shows that the stability factor of the bridge is bigger in the linear and elastic condition，while the value of the stabitity factor only decreased little when taking into account geometrical nonlinearity．But when the geometrical nonlinearity and material nonlinearity are all considered，the value of the stability factor decreased approximate 50％．It also shows that the instability of CFST arch bridge almost happens in the plastic area，and stress of the instability is biggBr than the higll-point of the elastic stress．The stability factor will be very bigger if the linear method is used in analyzing the stability of the bridge．So the ultimate loading is exact only when we consider the gcome删cal nonlinearity and material nonlinearity． The effect of different蠡ctom such as the disposal of the lateral braces，the stiffness of the main arch-ring and deck construction，the effect of non-orientemy conservative loadings of the hanger is discussed，and the rati