铁路斜拉桥带水平K撑钢桁梁局部受力特性分析及模型试验研究

发布时间：2018-11-18 17:56

【摘要】：新建铁路贵阳至广州线北江特大钢桁斜拉桥首次采用带水平K撑的纵横梁桥面系,该桥面系是对传统纵横梁桥面体系全新的改进。两端边跨及靠近边跨端的次边跨4个节间采用混凝土桥面板,其余部分采用正交异性钢桥面。通过仿真分析,对高速铁路专用斜拉桥的桥面系结构受力行为进行深入研究。初步探讨不同K撑构造对桥面结构受力的影响,为其他同类桥梁的桥面系设计提供参考。在仿真分析的基础上,以水平K撑构造为核心,优化模型结构及辅助构造,构建局部K撑节段静载试验模型,从而获得铁路钢桁梁斜拉桥带水平K撑桥面系的实际受力状况。主要研究内容和成果如下：1、结构分析,包括全桥杆系模型分析和杆系结合壳单元的多尺度仿真模型分析。前者使用MIDAS有限元软件进行计算分析,确定K撑在全桥中最不利受力位置。后者采用ANSYS有限元软件建立K撑最不利受力位置处的节段空间壳单元模型,重点分析局部应力分布。通过仿真分析,研究K撑、纵梁、横梁等杆件在恒载和活载作用下的传力机理及其局部的应力水平。计算结果表明：各杆件的应力水平均较低,K撑结构能有效减小纵梁、横梁和横肋的面外弯曲产生的水平应力,解决传统纵横梁桥面系横梁截面处面外弯曲所产生的应力超限问题。2、初步探讨不同K撑构造形式对桥面系结构受力行为的影响。通过对不设置K撑、T型截面K撑以及工字型截面K撑三种桥面系中的纵梁、横梁、横肋、下弦杆整体节点以及K撑等进行受力特性分析,得出T型截面K撑桥面系能够有效的降低杆件的局部应力,桥面受力更加合理。3、在仿真分析的基础上,以K撑结构为主要研究对象,构建局部K撑节段静载试验模型,进行模型试验研究。由试验结果可知：各杆件的实测应力与理论值较为吻合,采用有限元数值分析对桥梁结构局部应力分析是行之有效的。在加载过程中,各测点均处于弹性工作状态,结构应力满足规范要求,说明结构具有较大的安全储备。
[Abstract]:The bridge deck system with horizontal K brace is adopted for the first time in the Beijiang extra large steel truss cable-stayed bridge of the Guiyang to Guangzhou railway line. The deck system is a new improvement on the traditional bridge deck system. At both ends and near the side span, the concrete deck slab is used in the four intersections, and the other parts are orthotropic steel deck. Through simulation analysis, the behavior of deck structure of cable-stayed bridge for high-speed railway is studied. The influence of different K-brace structures on the stress on the deck structure is discussed, which provides a reference for the design of bridge deck system of other similar bridges. On the basis of simulation analysis, taking horizontal K brace structure as the core, the model structure and auxiliary structure are optimized, and the static load test model of local K braced section is constructed, thus the actual force condition of horizontal K braced bridge deck system in railway steel truss girder cable-stayed bridge belt is obtained. The main research contents and results are as follows: 1. Structural analysis, including the analysis of the full bridge member model and the multi-scale simulation model of the member system combined with shell element. The former is calculated and analyzed by MIDAS finite element software to determine the most unfavorable position of K braces in the whole bridge. The ANSYS finite element software is used to establish the segmental spatial shell element model at the most unfavorable position of K-braces, and the local stress distribution is analyzed emphatically. The mechanism of force transfer and the local stress level of K brace, longitudinal beam and cross beam under dead and live load are studied by simulation analysis. The results show that the stress level of each member is low, and the horizontal stress caused by the out-of-plane bending of the longitudinal beam, the transverse beam and the transverse rib can be effectively reduced by the K-braced structure. In order to solve the problem of stress overrun caused by the bending of the cross section of the traditional longitudinal and transverse beams, the influence of different K-braced structures on the behavior of the bridge deck structure is discussed preliminarily. The stress characteristics of longitudinal beam, transverse rib, integral joint of lower chord and K brace in three kinds of bridge deck systems without K brace, T section K brace and I section K brace are analyzed. It is concluded that the T-section K-braced deck system can effectively reduce the local stress of the members, and the stress on the deck is more reasonable. 3. On the basis of simulation analysis, taking K-braced structure as the main research object, the static test model of the local K-braced section is constructed. Model test was carried out. The experimental results show that the measured stress of each member is in good agreement with the theoretical value, and the finite element numerical analysis is effective for the local stress analysis of the bridge structure. In the process of loading, the measured points are in elastic working state, and the structural stress meets the requirements of the code, which indicates that the structure has a large safety reserve.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U448.27;U441

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