大跨度钢箱异型拱桥内力分析及稳定性研究

发布时间：2018-03-27 18:21

  本文选题：异型拱桥　切入点：内力　出处：《沈阳建筑大学》2014年硕士论文

【摘要】：拱桥是一种历史悠久的桥梁形式,随着科技的发展,基于美学方面的考虑使得现代拱桥正向着大跨度、复杂体系方向发展,因此作为主要受压的构件,拱桥的稳定问题越来越突出,成为制约其发展的主要因素。拱桥拱肋在承压的同时还承受一定的弯矩、扭矩和剪力的作用,受力形式复杂,因而在施工及运营过程中存在的稳定问题较突出。本文以某“M”形异型拱桥为例主要研究内容如下：(1)、分析桥梁结构体系,根据该桥结构特点和实际情况采用桥梁结构专业软件MIDAS CIVIL建立全桥有限元模型,并对实际施工过程进行仿真模拟。通过对该桥进行成桥状态的静力分析,对桥梁内力、应力、位移及吊杆索力进行设计、验算,最终保证桥梁施工的顺利进行,及成桥后高速行车的舒适度和安全性。(2)、对全桥进行内力应力以及位移的计算分析,得出拱肋各截面所受应力情况以及钢混结合段与索梁结合处的弯矩剪力变化。分析了全桥各构件的位移变化和吊杆受力特性与吊杆的安全系数。(3)、对全桥进行两类稳定性分析,其中第一类稳定为特征值的问题,对实际工程有重要的指导意义。但其理论意义很大,但实际中由于结构的初始缺陷及材料自身存在的问题,研究其理论意义不大,故对其进行第二类失稳分析,所以在分析时考虑了几何非线性的影响,这样才会得出对工程有现实意义的结果。本文以某“M”形拱桥为工程背景,通过第一类稳定性分析,研究了影响这种桥型稳定性的各种结构参数,掌握了各种结构参数变化对拱桥稳定影响的规律。同时也对Ⅱ号拱肋进行了几何非线性稳定的稳定分析。计算结果表明,全桥稳定安全储备较高,稳定性薄弱位置为Ⅱ号拱肋,其拱肋因拱顶横撑的存在所以失稳形式主要以面内失稳为主,工况一作用下稳定系数为38.73。在复杂体系桥梁中几何非线因素对稳定分析影响较大,必须加以考虑。文中对某异型拱桥的进行了稳定性分析,结果表明施工过程稳定性达到安全标准。(4)、分析了影响异型拱桥稳定的几点因素,包括吊杆件间距的大小,矢跨比的影响以及拱肋的倾斜角度的影响,计算分析结果表明,拱肋的稳定系数随着吊杆间距的增大而呈现递减趋势,增大吊杆间距可以节省材料,减少工程造价,但是却降低了结构的稳定性,所以在设计选择吊杆间距时应综合考虑,矢跨比在1/3.5—1/5之间为最优,当矢跨比大于1/3.5时,结构的稳定系数随之增大而增大。拱肋倾斜角度在0°-16°时稳定性随之增加而增大,16。之后基本保持不变。所以在选择倾斜角度时应按实际所需选取最优角度。
[Abstract]:Arch bridge is a kind of bridge form with a long history. With the development of science and technology, modern arch bridge is developing towards the direction of long span and complex system based on aesthetic considerations. The stability problem of arch bridge is more and more prominent and becomes the main factor restricting its development. The arch rib of arch bridge is subjected to bending moment, torque and shear force at the same time, and the force form is complex. Therefore, the stability problems in the construction and operation process are prominent. This paper takes a "M" shaped shaped arch bridge as an example to analyze the bridge structure system as follows: 1. According to the characteristics of the bridge structure and the actual situation, the finite element model of the whole bridge is established by using the bridge structure professional software MIDAS CIVIL, and the actual construction process is simulated. Through the static analysis of the bridge state, the internal force and stress of the bridge are analyzed. The displacement and suspension cable force are designed, checked and calculated to ensure the smooth construction of the bridge, and the comfort and safety of high-speed driving after the completion of the bridge. The internal force stress and displacement of the whole bridge are calculated and analyzed. The stress of each section of arch rib and the change of moment and shear force at the joint of steel concrete and cable beam are obtained. The displacement change of each member of the bridge and the stress characteristics of the suspender and the safety factor of the suspender are analyzed, and two kinds of stability analysis of the whole bridge are carried out. The problem that the first kind of stability is eigenvalue has important guiding significance for practical engineering, but its theoretical significance is very great, but in practice due to the initial defects of the structure and the problems existing in the material itself, it is of little theoretical significance to study it. Therefore, the second kind of instability analysis is carried out, so the influence of geometric nonlinearity is taken into account in the analysis, so that the result of practical significance can be obtained. In this paper, a certain "M" arch bridge is taken as the engineering background and the stability analysis of the first type is carried out. The influence of structural parameters on the stability of the arch bridge is studied, and the influence of structural parameters on the stability of the arch bridge is studied. The geometric nonlinear stability of the arch rib is also analyzed. The results show that the stability of the arch rib is affected by the influence of the structural parameters on the stability of the arch bridge. The stability safety reserve of the whole bridge is high, the weak position of the stability is the 鈪，

本文编号：1672690