【作者】 徐品瑞；

【导师】 郑振；

【作者基本信息】 福州大学 ， 结构工程， 2004， 硕士

【摘要】 近年来随着高等级公路的修建，由于城市立交桥建设的需要，曲线梁桥在我国已被广泛采用。在截面的选择上，由于箱形截面良好的结构性能，使得其成为曲线梁桥设计中常采用的截面形式。但在弯箱梁桥的设计中，设计者首先遇到的麻烦就是反映其结构性能及截面特性的结构分析问题。本文采用有限段元方法进行薄壁弯箱梁的结构分析，单元每节点考虑10个自由度，并引入线性修正系数考虑沿梁宽方向曲率变化的影响。节点自由度充分反映了薄壁弯箱梁桥的结构力学特性且通过线性修正系数降低了薄壁弯箱梁桥结构分析的维数。本文在进行薄壁弯箱梁桥结构分析时，由虚功原理建立了薄壁弯箱梁桥结构分析的弹性控制微分方程组，通过对该微分方程组进行求解并结合刚度系数的物理意义得到了薄壁弯箱梁桥有限段元分析的单元刚度矩阵，从而可以用一般杆系结构的刚度法对薄壁弯箱梁进行结构受力特性分析。此外，对于混凝土薄壁弯箱梁结构，考虑混凝土的收缩、徐变效应，这是不可忽视的内容。但混凝土收缩、徐变效应的分析是一个十分复杂又难以获得精确答案的问题。在实际工程的收缩、徐变效应分析中，合理的选择收缩、徐变计算模式成了一个关键的内容。本文简单介绍了混凝土收缩、徐变的基本机理、影响因素等。并简单探讨了我国《公路钢筋混凝土及预应力混凝土桥梁规范》（JTJ023-85）所规定的收缩、徐变模式、CEB-FIP1990模式、B3模式。同时，通过引入按龄期调整的有效弹性模量，对薄壁弯箱梁桥有限段元分析的单元刚度矩阵进行修正，并根据卡斯提亦努（Castigliano）第一定理建立薄壁弯箱梁桥徐变效应有限元逐步法分析的刚度方程，从而按照有限元分析的一般方法进行薄壁弯箱梁桥结构的徐变效应分析。最后本文引入两个算例，并采用本文方法所编制的程序进行计算分析。通过分析计算结果得出了结论。更多还原

【Abstract】 Recently with the construction of the super high way and urban over-bridge,curve-ed bridge has been built far and wide in our country.Because of the good forcing property of the box-section,it has been used in the curved bridge frequently.But during the course of curved box-girder bridge design,there is any difficulty to analyse the property of the structure and the section correctly. In this paper,the author analyse the thin curved box-girder with FEM,every element has ten freedoms,which reflect the forcing property of thin curved box-girder structure.In this paper,author establish the elastic governing differential equations for structural analysis by the principle of virtual work.Then attain an element stiffness by quadraturing the equations with physical significance meaning of coefficient.At last the structural foring property of thin curved box-girder can be analysed by FEM.On the other hand,it is a necessary content to analyse the concrete shrinkage and ceep in thin curved box-girder structure.But it is a complex problem which can’t be accomplished accurately.In practice,it is a key content to select a reasonable model of concrete shrinkage and creep.In this paper the author introduce the fundamental principle and influence factor of concrete shrinkage and creep etc.Then discuss the three models in 《Specifications for Design of Reinforced Concrete and Prestressed Concrete Highway Bridges and Culverts》、CEB-FIP1990、B3.And then establish a stiffness equation to analyse the shrinkage and creep in thin curved box-girder bridge,which based on Castigliano theorem with an amending stiffness matrix by FEM.At last,the author analyse two examples with the program writed according to the method which discussed in this paper.Then analyse the calculate result and draw any conclusion.更多还原