独塔叠合梁斜拉桥空间力学行为研究

发布时间：2018-10-20 19:24

【摘要】：随着交通运输事业的发展、计算理论的完善及现代施工技术的进步,现代斜拉桥的跨径越来越大,其结构受力也越来越复杂,空间效应更为明显。近几十年的桥梁事故表明全桥整体分析结果因忽略结构局部构造而与桥梁结构的真实力学行为存在较大的差异。斜拉桥结构的某些部位存在应力集中、剪力滞、应力扩散等问题,而这些部位的安全储备也往往是保证该类结构工程质量的关键。因此,有必要在全桥整体分析的基础上对这些部位进行局部精细化的有限元分析,从而精确掌握其受力情况。本文以鳌江四桥为具体工程背景,在以大跨径钢-混叠合梁斜拉桥健康监测为目的基础上,运用有限元原理对其空间力学行为进行研究,主要工作如下:(1)通过建立全桥空间有限元模型,对独塔钢混叠合梁斜拉桥整体空间力学行为进行研究。主要分析其成桥初期恒载和成桥后期考虑混凝土收缩徐变作用及运营期恒载、汽车、温度、风载等作用下结构内力、应力及变形情况。(2)在整体分析的基础上,找出最不利工况下的受力最不利梁段;基于多尺度原理建立该梁段的局部精细化有限元模型,研究混凝土桥面板、钢纵横梁、钢梁纵横向加劲体系的空间应力分布状态及相互之间的力学传递机理,为精细化设计提供依据。(3)根据鳌江四桥实际施工顺序,将整个施工过程分为128个施工阶段,通过正装分析方法对其施工过程进行模拟计算,对各构件在不同施工阶段中的静力行为和内力分布特点进行分析,探讨施工全程中桥体关键部位内力演变机理及施工过程中斜拉索索力对结构应力及变形的影响,为指导施工提供参考。
[Abstract]:With the development of transportation, the improvement of calculation theory and the progress of modern construction technology, the span of modern cable-stayed bridge is becoming larger and larger, the structure of which is more and more complicated, and the spatial effect is more obvious. The bridge accidents in recent decades show that there is a great difference between the analysis results of the whole bridge and the real mechanical behavior of the bridge structure because of neglecting the local structure of the structure. Stress concentration, shear lag and stress diffusion exist in some parts of cable-stayed bridge structure, and the safety reserve of these parts is often the key to ensure the engineering quality of this kind of structure. Therefore, it is necessary to make local fine finite element analysis of these parts on the basis of the whole bridge analysis, so as to accurately grasp the force situation. In this paper, the spatial mechanical behavior of Aojiang fourth Bridge is studied by using finite element principle on the basis of health monitoring of long-span steel-hybrid cable-stayed bridge. The main work is as follows: (1) the spatial mechanical behavior of the cable-stayed bridge with single-tower steel concrete composite beam is studied by establishing the spatial finite element model of the whole bridge. This paper mainly analyzes the internal force, stress and deformation of the structure under the action of dead load, automobile, temperature, wind load and so on. (2) on the basis of the whole analysis, the concrete shrinkage and creep are considered in the early stage of the bridge and in the later stage of the bridge. Find out the most unfavorable beam section under the most unfavorable working condition, establish the local fine finite element model of the beam segment based on the multi-scale principle, study the concrete bridge deck slab, steel longitudinal and horizontal beam, The spatial stress distribution state of steel beam longitudinal and transverse stiffening system and the mechanism of mechanical transfer between them provide the basis for fine design. (3) according to the actual construction sequence of Aojiang fourth Bridge, the whole construction process is divided into 128 construction stages. The static behavior and internal force distribution characteristics of each component in different construction stages are analyzed by simulating and calculating the construction process by means of the formal fitting analysis method, and the characteristics of the static behavior and internal force distribution of the components in different construction stages are analyzed. This paper probes into the evolution mechanism of internal force in the key part of bridge body during the whole construction and the influence of cable force on the stress and deformation of the structure during the construction process, which provides a reference for guiding the construction.
【学位授予单位】：西安建筑科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U448.27

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