高墩大跨刚构—连续组合梁桥几何非线性与稳定性分析

发布时间：2019-01-08 13:57

【摘要】：近几十年来,我国大力发展基础设施建设,公路桥梁发展迅速,刚构-连续组合梁桥作为主要桥型之一,在全国范围内得到不断推广和应用,且逐渐朝着高墩大跨的方向发展,由于桥墩长细比不断增大,主梁跨度的进一步延长,几何非线性效应对桥梁位移和内力影响不能忽视,另一方面,结构越来越柔,桥梁的稳定问题也越来越受得重视。本文简要介绍了刚构-连续组合梁桥的特点、国内外发展状况以及未来的发展趋势；对几何非线性理论的发展及基本特点进行了阐述,比较了U.L列式法和T.L列式法的不同点,推导了U.L列式法的增量平衡方程,同时对几种非线性方程的解法进行了分析讨论；桥梁失稳通常考虑两类稳定问题,第一类稳定问题为表现为分支点失稳,第二类稳定问题表现为极值点失稳。第一类稳定问题也即特征值问题,求解较为方便且它的临界荷载与第二类稳定问题的极限荷载相近,因此对结构进行第一类稳定问题分析具有重要的工程意义。本文以矮寨刚构桥为背景,采用大型桥梁软件MIDAS/CIVIL建立有限单元模型,基于非线性理论,分析几何非线性效应对高墩悬臂状态和成桥状态的位移及内力的影响,并与线性条件下的结果作比较,研究几何非线性效应对桥梁影响程度；另一方面,结合稳定理论,对矮寨刚构桥高墩的自体稳定、悬臂状态及成桥运营阶段进行稳定性分析,研究风荷载、混凝土强度、高墩壁厚及单双肢体系等对桥梁稳定性的影响,分析各因素作用下高墩大跨刚构-连续组合梁桥的稳定性,以便为高墩大跨桥梁的设计、施工及加固等方面提供一些帮助。
[Abstract]:In recent decades, our country vigorously develops the infrastructure construction, the highway bridge develops rapidly. As one of the main bridge types, the rigid-frame continuous composite beam bridge has been continuously popularized and applied in the whole country, and has gradually developed towards the direction of high pier and long span. Due to the increasing slenderness ratio of piers and the further extension of the span of the main beam, the influence of geometric nonlinearity on the displacement and internal force of the bridge can not be ignored. On the other hand, the structure becomes more and more flexible, and the stability of the bridge is paid more and more attention. This paper briefly introduces the characteristics of rigid-frame-continuous composite beam bridge, the development situation at home and abroad and the future development trend. The development and basic characteristics of geometric nonlinear theory are expounded, the differences between U.L formulation method and T.L formulation method are compared, and the incremental equilibrium equation of U.L formulation method is derived. At the same time, the solutions of several nonlinear equations are analyzed and discussed. There are usually two kinds of stability problems for bridge instability. The first kind of stability problem is shown as branching point instability and the second kind of stability problem is extreme point instability. The first kind of stability problem, which is called eigenvalue problem, is easy to solve and its critical load is close to the limit load of the second kind of stability problem. Therefore, it is of great engineering significance to analyze the first kind of stability problem of structure. In this paper, the finite element model is established by using the large scale bridge software MIDAS/CIVIL. Based on the nonlinear theory, the influence of geometric nonlinear effect on the displacement and internal force of cantilever state and bridge state of high pier is analyzed. Compared with the results under the linear condition, the influence degree of the geometric nonlinear effect on the bridge is studied. On the other hand, combined with the stability theory, the stability analysis of the high pier of the short stockaded rigid frame bridge is carried out in order to study the wind load, the strength of concrete, the state of cantilever and the operation stage of the bridge. The influence of wall thickness of high pier and single double limb system on the stability of bridge is analyzed. The stability of long span rigid frame continuous composite beam bridge with high piers under the action of various factors is analyzed in order to provide some help for the design, construction and reinforcement of long span bridge with high pier.
【学位授予单位】：长沙理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441

【共引文献】