悬索桥板桁结合桥面系力学特性及剪力滞计算方法研究

发布时间：2018-06-30 17:29

本文选题：悬索桥 + 板桁结合桥面系　；参考：《西南交通大学》2014年硕士论文

【摘要】：大跨度悬索桥的发展方兴未艾,随着跨度的增大,恒载在总荷载中的比重进一步增加,这对主缆、加劲梁等构件的设计、制作及安装提出更高要求。将桥面与主桁结合起来的板桁结合桥面系能够较为有效地减轻结构恒载、简化传统桁梁悬索桥的桥面系构造。但目前采用该结构的悬索桥较少,对其认识及研究还不深；且该结构构造复杂,正交异性板构件纵横交错,如何对其进行简化计算需要进一步的研究。针对以上问题,本文主要通过以下几个方面对板桁结合桥面系加劲梁进行分析研究： (1)、对不同结合方式的桁架加劲梁进行计算分析,研究板桁结合型与分离式桥面系加劲梁力学性能的异同；对不同钢桥面支撑方式的板桁结合桥面系在第一系统荷载、桥面荷载作用下进行计算分析,借此研究板桁结合桥面系的合理构造及力学特性。 (2)、将普通桁架等效剪切厚度的求解方法运用于悬索桥板桁结合桥面系中,编制了桁梁连续化程序、平面杆系几何非线性程序；讨论了刚性节点、剪切变形对结构内力位移的影响,提出了板桁结合桥面系加劲梁整体计算时较为合理的简化模型。 (3)分析得到了悬索桥板桁结合桥面系全桥范围内的剪力滞变化规律；据此讨论了板桁结合桥面系的纵向位移函数。在连续化桁梁的基础上,采用变分法得到了简支梁受均布荷载、集中荷载的剪力滞微分方程解析解,提出了基于离散吊索力及弯矩影响区间的悬索桥板桁结合桥面系剪力滞计算分析方法,并对其影响参数进行了讨论。 (4)考虑到变分法求解的局限性,本文根据能量法及虚功增量方程详细地推导了考虑剪切变形及剪力滞影响的梁单元弹性刚度矩阵、几何刚度矩阵,编制相关程序；通过与ANSYS的对比验证了本文程序的精度。通过本文的分析研究,得到了悬索桥板桁结合桥面系加劲梁的力学特性、换算梁法合理的简化模型及剪力滞的计算分析方法。本文的研究表明：板桁结合桥面系加劲梁受力复杂,计算分析可根据不同的力学特点来选取不同的简化模型；采用换算梁法进行整体计算时考虑刚性节点及剪切变形的影响能够提高计算精度；本文提出的基于离散吊索力及弯矩影响区间的剪力滞分析方法,对于悬索桥加劲梁剪力滞求解具有物理概念清楚、易程序化的优点,且精度较高,但该方法受限于剪力滞微分方程的求解；对于含有较为复杂纵向位移函数的剪力滞问题,采用本文提出的基于插值函数的剪力滞一维梁段有限元法较为方便。
[Abstract]:The development of long-span suspension bridge is in the ascendant. With the increase of span, the proportion of dead load in the total load increases further, which puts forward higher requirements for the design, manufacture and installation of the main cable, stiffening beam and other components. The slab-truss deck system combined with the main truss can effectively reduce the dead load of the structure and simplify the structure of the deck system of the traditional truss suspension bridge. However, there are few suspension bridges with this structure, and the structure is complex and orthotropic plates are crisscrossed, how to simplify the calculation needs further study. In view of the above problems, this paper mainly through the following aspects of the slab truss bridge deck stiffening beam analysis: (1) the different combination of truss stiffening beam calculation and analysis, This paper studies the difference and similarities of the mechanical properties of stiffened beams of plate-truss and split-type deck systems, calculates and analyzes the slab-truss composite deck systems with different steel deck support modes under the first system load and deck load. In order to study the reasonable structure and mechanical properties of slab-truss composite deck system. (2) the method of equivalent shear thickness of common truss is applied to the slab-truss composite deck system of suspension bridge, and the continuous program of truss beam is compiled. The effects of rigid joints and shear deformation on the internal force displacement of the structure are discussed. A reasonable simplified model is proposed for the whole calculation of stiffened beam of slab-truss composite deck system. (3) the shear lag variation law in the whole bridge range of slab-truss composite deck system of suspension bridge is obtained. Based on this, the longitudinal displacement function of slab truss combined bridge deck system is discussed. On the basis of continuous truss beam, the analytical solution of shear lag differential equation of simply supported beam subjected to uniform load and concentrated load is obtained by using variational method. In this paper, a method for calculating and analyzing the shear lag of slab-truss combined deck system of suspension bridge based on the influence interval of discrete slings force and bending moment is proposed, and its influence parameters are discussed. (4) considering the limitation of variational method, Based on the energy method and the virtual work increment equation, the elastic stiffness matrix and geometric stiffness matrix of beam element considering shear deformation and shear lag are derived in detail in this paper, and the relative programs are compiled, and the accuracy of the program is verified by comparing with ANSYS. Through the analysis and research in this paper, the mechanical characteristics of stiffened beam of slab-truss combined deck system of suspension bridge are obtained, the reasonable simplified model of conversion beam method and the calculation and analysis method of shear lag are obtained. The research in this paper shows that the stiffening beam of slab truss combined with bridge deck system is complicated, so different simplified models can be selected according to different mechanical characteristics. Considering the influence of rigid joints and shear deformation, the calculation accuracy can be improved by using the conversion beam method, and the shear lag analysis method based on the influence interval of discrete sling force and bending moment is proposed in this paper. The solution of shear lag of stiffened beam of suspension bridge has the advantages of clear physical concept, easy to program and high precision, but the method is limited by the solution of differential equation of shear lag. The finite element method of shear lag one-dimensional beam proposed in this paper based on interpolation function is more convenient.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441;U448.25

【参考文献】