高墩大跨径连续刚构弯桥全过程稳定性分析

【作者】 李文华；

【导师】 贺拴海；

【作者基本信息】 长安大学 ， 桥梁与隧道工程， 2005， 硕士

【摘要】 本文为国家西部交通建设科技项目《高墩大跨径弯桥的设计与施工技术研究》的子课题《高墩大跨径弯桥的全过程稳定分析》的重要组成部分。旨在通过大量的高墩大跨径连续刚构实桥的稳定性数值试验,寻求影响高墩大跨径直、弯连续刚构桥稳定的敏感性参数及内在规律,以指导生产实践。 本文在分析国内外稳定理论研究发展及现状的基础上,指出稳定问题同强度问题一样,在高墩大跨径桥梁中具有特别重要的意义,从而引出本文的研究内容。简要介绍了结构的两类稳定问题,指出实际工程结构中的稳定问题多为第二类稳定问题,而且只有通过对结构几何非线性和材料非线性本构关系的研究,才能深入揭示复杂稳定问题的实质。运用能量原理推导等截面高墩自体稳定临界荷载和悬臂施工阶段高墩稳定临界荷载的近似求解公式,尤其是对弯桥的高墩自体稳定性和悬臂施工阶段高墩稳定临界荷载的近似公式作了较为详尽的推导,整个推导过程简单明了,算法简单易行。给出了高墩大跨径连续刚构桥稳定性的有限元求解思路、方法以及基本步骤。通过算例分析验证自编桥梁稳定专用程序BridgeB-W的正确性;计算结果与大型通用程序ANSYS计算结果对比表明:该程序结构分析正确,计算方法可行,精度基本满足工程要求。以实桥为背景,采用大型通用程序ANSYS以及桥梁稳定专用程序BridgeB-W分析计算了多座连续刚构桥的稳定性,寻找了影响高墩大跨径连续刚构桥稳定性诸因素的内在规律,即高墩大跨径连续刚构桥在最大悬臂施工阶段,曲桥的稳定性较直桥差,而在成桥状态下,曲桥较直桥稳定性好;双薄壁墩若设1根系梁,其位置应设在1/2墩高处;若设2根系梁,其位置应靠近在1/2墩高处为佳;考率非线性因素的影响,弯连续刚构桥的稳定性其实已经转化为考虑材料屈服强度的极限承载力的问题等等。这些结论的提出将为同类桥型的设计、施工以及进一步的研究提供科学依据。更多还原

【Abstract】 The research in this paper is an important part of the stability analysis in the whole stage of large-span curved bridges with high piers which is a sub project of the national transportation scientifical project in western regions, the research of the design and construction technology of large-span curved bridges with high piers. In this paper, The purpose is to seek the stability sensitive parameters and the inner rules of straight and curved lone span continuous rigid-frame bridge with high piers which are applied for production through plentiful numerical tests to plenty of large-span continuous rigid-frame bridge with high piers.Besed on analysing the development and nowadays conditions of stability theory in and abroad, this paper points out that the stability is as significant as intensity to bridges large-span bridges with high piers. Consequently, the main goal of this paper is fetched out. Two kinds of stability problems are simply introduced and it points out that most stability problems come up against in practice is the second stability problem. Furthermore, we come to the conclusion that only if with the study to the relation of geometrical nonlinear to material nonlinear of structure can we deeply discover the essential of complicated stability problems. The formula deducted by energy theory which approximatively resolving critical load of self-stability and stability in cantilever construction of high pier with uniform section, and especially the approximate formulae of critical load of self-stability and stability in cantilever construction of high pier of curved bridge are deducted in detail. The deduction is briefly and prone to be operated. The way, the solution and the basic steps solving the stability of large-span continuous rigid-frame bridge with high piers using finite element are given. BridgeB-W, a self-write special bridge program, is validated by examples. The result is compared with ANSYS, a large current calculation program, to make clear that the result by BridgeB-W is exact and the precision satisfy the need of engineering. The stability of several large-span continuous rigid-frame bridges with high piers are calculated and analysed by ANSYS and BridgeB-W. As a result, the inner rules influencing the stability of large-span continuous rigid-frame bridge withhigh piers are initially brought forward, that is, the stability of curved bridge is not as good as straight bridge on the stage of the most cantilever cast, while the thing is reversed when a whole bridge is completed; to double thin-wall pier, it’s good to set one tie girder at the spot of the half of a pier while it’s good to set two tie girders near the spot of the half of a pier; in view of the effect of nonlinear, it come to the conclusion that the stability of curved continuous rigid-frame bridge translates into the problem of limit load considering material maximum intensity, etc. The conclusion can provide reference to the design and construction of the same type, and also lay a foundation for the further study.更多还原