大跨度连续桥梁悬臂施工监控与风荷载效应分析

发布时间：2018-02-02 17:00

本文关键词： 连续梁桥施工监控风荷载计算流体力学　出处：《兰州交通大学》2015年硕士论文　论文类型：学位论文

【摘要】：快速发展的预应力技术使得连续梁桥向大跨度发展成为可能。伴随着混凝土收缩徐变、温度、风荷载等因素对大跨度桥梁影响研究的不断深化,对桥梁施工控制精度的要求也越来越高。大跨度桥梁施工控制不但要满足安全方面的需求,而且还要使得线形和应力方面符合设计要求。由于预应力混凝土连续梁桥不断向高墩、大跨方向发展,加之这种桥型常用于大风区域,风荷载对其施工的影响日渐突出,忽略风荷载的影响将会使桥梁的线形和应力不符合设计的要求,并有可能给桥梁施工带来不可预料的后果。因此,研究风荷载对连续梁桥施工产生的影响显得日趋必要。到目前为止,研究风荷载对桥梁断面的作用所采用的方法主要是风洞试验。但是由于风洞试验的消费较大,且试验的时间过长,故其适用性不广泛。近年来,随着计算机技术的发展,计算流体力学已取得了很大的进步,逐渐的成为研究桥梁断面三分力系数的最佳方法。本文以阿尔滨跨登沙河特大桥为例,介绍了连续梁桥的施工监控及其监控方法和内容。并以主梁各典型截面和施工过程中的最大悬臂结构为研究对象,分别利用Fluent和Midas-Civil软件去分析强风对桥梁断面的响应和对悬臂结构的作用,从而得出风荷载对连续梁桥所产生的影响。(1)首先介绍了连续梁桥施工监控的基础知识,包括施工监控的目的和主要内容。然后以阿尔滨跨登沙河特大桥为例,介绍了运用Midas-Civil有限元软件模拟三跨连续梁桥的基本步骤,计算得出本桥在各个施工阶段的应力和变形,为本桥的施工监控提供理论数据。在施工的过程当中严格按照已经制定的监控方案,对施工各个阶段梁体的受力、线形等数据进行实际量测,再通过实测值与理论值的对比、分析、寻找原因等,发现误差,对误差进行纠正,在施工过程中尽量使实际值与理想值接近,不断循环上述步骤,并保证在施工过程中理论应力与实际应力以及理论位移与实际位移差值始终不超过允许值,最终确保桥梁的顺利合拢。(2)以阿尔滨跨登沙河特大桥为工程实例,用Fluent分别模拟风荷载在-5°、0°、5°三个风攻角作用下,主梁截面的三分力系数随来流风攻角及截面几何尺寸的变化情况,并给出其各典型截面在不同来流风攻角作用下的速度云图和流线图。通过对主梁截面的风荷载响应进行分析得出主梁的主要受力情况,从而为桥梁的设计和施工提供指导。(3)模拟风荷载对施工过程中最大悬臂结构的作用,得出最大悬臂结构在不同工况风荷载作用下的应力与位移,并分析比较它们的变化和产生的原因。了解风荷载对悬臂施工过程中梁体应力和位移结果的影响,从而更好的为施工及设计提供帮助。
[Abstract]:The rapid development of prestressed technology makes it possible for continuous beam bridges to develop to long span. With the continuous deepening of research on the impact of concrete shrinkage creep temperature wind load and other factors on long-span bridges. The control precision of bridge construction is more and more high. The construction control of long-span bridge should not only meet the needs of safety. Because the prestressed concrete continuous beam bridge develops to the high pier and the long span direction, the bridge type is often used in the high wind region. The influence of wind load on its construction is becoming more and more prominent. Ignoring the influence of wind load will make the alignment and stress of the bridge not meet the design requirements, and may bring unpredictable consequences to the construction of the bridge. It is increasingly necessary to study the influence of wind load on the construction of continuous beam bridges. Wind tunnel test is the main method to study the effect of wind load on bridge section. However, due to the large consumption of wind tunnel test and too long test time, its applicability is not widely used in recent years. With the development of computer technology, computational fluid dynamics has made great progress, and gradually become the best method to study the cross-section force coefficient of the bridge. This paper takes the Albin span Dengsha River Bridge as an example. This paper introduces the construction monitoring and control methods and contents of continuous beam bridge, and takes each typical section of the main beam and the maximum cantilever structure in the construction process as the research object. Fluent and Midas-Civil software are used to analyze the response of the strong wind to the bridge section and the role of the cantilever structure. Thus, the influence of wind load on continuous beam bridge is obtained. Firstly, the basic knowledge of continuous beam bridge construction monitoring is introduced. The purpose and main contents of construction monitoring are included. Then taking Albin span Dengsha River Bridge as an example, the basic steps of simulating three-span continuous beam bridge with Midas-Civil finite element software are introduced. Calculate the stress and deformation of the bridge in each stage of construction, provide theoretical data for the bridge construction monitoring. In the process of construction, strictly according to the established monitoring scheme, the construction of each stage of the beam force. Through the comparison of measured data and theoretical values, analysis, find reasons, find errors, correct the errors, make the actual value and ideal value as close as possible in the construction process. Cycle the above steps continuously and ensure that the theoretical stress and the actual stress and the difference between the theoretical displacement and the actual displacement do not exceed the allowable value in the construction process. Finally, to ensure the smooth closure of the bridge. (2) taking the Albin span Dengsha River Bridge as an engineering example, using Fluent to simulate the wind load under the action of -5 掳0 掳0 掳5 掳wind attack angle respectively. The variation of the three-point force coefficient of the main beam section with the incoming wind attack angle and section geometry size. The velocity cloud diagram and streamline diagram of each typical section under the action of different attack angles of incoming wind are given. By analyzing the wind load response of the main beam section, the main force situation of the main beam is obtained. Thus provide guidance for the design and construction of bridges. 3) simulate the effect of wind load on the maximum cantilever structure in the construction process, and obtain the stress and displacement of the maximum cantilever structure under different conditions of wind load. The influence of wind load on the stress and displacement of beam during cantilever construction is analyzed and compared, so as to provide better help for construction and design.
【学位授予单位】：兰州交通大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U445.466

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