【作者】 崔婷；

【导师】 周绪红；

【作者基本信息】 长安大学 ， 桥梁与隧道工程， 2008， 硕士

【摘要】 曲线预应力混凝土箱梁桥以其经济、美观、实用的特点在我国的桥梁建设中已经被广泛的采用。然而由于曲线预应力混凝土箱梁桥在力学性能、荷载、构造和施工工艺等方面的复杂性,及计算程序的易用性,目前仍有许多课题急待解决。本文课题研究的主要目的是针对目前曲线梁桥分析的复杂性,选用适当的计算理论,编制简洁易用友好的有限元程序,解决曲线梁在有限元分析中的一系列问题。采梁格法对曲线预应力混凝土箱梁桥进行有限元分析,用每结点六个自由度的空间直杆单元来分析梁格的纵横构件,并推导空间直梁单元的单元刚度矩阵、坐标转换矩阵和整体刚度矩阵,并对边界条件的处理进行了讨论,对钢束几何要素的计算公式进行推导,分析了各种预应力损失,推导出预应力等效荷载的表达式,并通过等效荷载计算预应力束的总效应和二次内力。对网格划分和梁格刚度的取值进行研究,提出了梁格法分析曲线预应力混凝土箱梁桥时划分网格数目的确定方法:用梁格法分析曲线梁桥时,当每根纵向梁格构件所对应的圆心角在4~5度之间时,若再细分网格对结果的影响已经不大,此时可以认为结果已经收敛,用一算例来说明上部结构梁格截面特性的取值。在Fortran PowerStation4.0集成开发环境下采用Fortran90语言将上述内容编制成程序,并采用Visual Basic 6.0语言为程序编制了友好的交互性输入界面。最后通过实桥算例验证了本文理论分析的正确性和程序的精确性。更多还原

【Abstract】 Curved prestressed-concrete box-girder bridge, with its economic, aesthetic and practical features, has been widely adopted in China bridge construction. But because of the complexity in mechanical properties, loadings, structure, construction technology, and other aspects,and easy using in calculating program,many issues are still there to be resolved. The main problem researched in this paper is to workout a friendly finite element program,under the complexity in curved girder bridge analysis,which is using proper calculating theories,to solve a series of the problem in curved girder bridge finite element analyse.In this paper, grillage analogy has been used in finite element analysis on curved beam bridge, three-dimensional straight-lever unit, which has six degrees of freedom for each node, is used to analyse the vertical and horizontal structure of the grillage, element stiffness matrix, coordinate transformation matrix and overall stiffness matrix for straight beam element is derived,the handling of boundary conditions is discussed, and the equivalence load of the prestressing force has been envolved, then the gross effect of prestressed reinforcement and secondary internal force is calculated through equivalent load.To research the value of meshed grid and beam stiffness, the method of confirming the value of meshing grid and beam stiffness when analysising the prestressed concrete box-girder bridge by grillage was educed: while meshing the girder by grillage, when each vertical beam grid components corresponding to the central angle in four to five degrees, if the breakdown of the results of the grid had little impact, the results were convergence. An example used to illustrate the structure of the upper beam cross-section of the grid value.The above-mentioned content is programming under Fortran90 language in Fortran PowerStation4.0 integrated development environment, static analysis module is obtained through straight-lever grillage finite-element method for superstructure of curved beam bridge, Visual Basic 6.0 language is used to programming a friendly interactive input interfaceFinally, the correctness of this theoretical analysis and the accuracy of this program are verified through the calculation example.更多还原