PC连续梁桥悬臂施工临时固结简化模式及合龙误差对成桥线形的影响研究

发布时间：2018-07-01 12:06

本文选题：临时固结 + 简化模式　；参考：《兰州交通大学》2015年硕士论文

【摘要】：在PC连续梁桥的施工过程中,往往需要通过施工控制以保证主梁的成桥线形。本文以三跨连续梁为工程背景,利用Midas/civil建立桥梁结构的计算模型,针对悬臂施工控制中墩梁临时固结的相关问题、合龙附加压重的计算及其对成桥后结构线形的影响作了相应的分析和探索。主要完成以下工作并得出相关结论:(1)在查阅相关资料的基础上,了解预应力混凝土连续梁桥的发展历程和悬臂施工的特点,并对悬臂施工中临时固结、压重的确定及实施措施进行了探讨。(2)针对临时固结受力分析中计算模型存在的问题,通过对杆系模型中临时固结模拟方法的研究,探索其在不同施工阶段对结构状态的影响。(3)在计算分析临时固结弹性支撑刚度的基础上,以主梁转角刚度为主要参数,探讨临时固结刚度、桥墩刚度对体系转换过程中主梁变形的影响,结果表明:临时固结是一种弹性连接,铰接和固结是它的两种极限状态;当墩梁转角刚度比值很大时,施工控制计算中可以不计入桥墩的影响。(4)在对强制合龙工程措施作用效果分析的基础上,针对施工中合龙段两端出现相对高差的现象,按照两种合龙顺序分别推导相应的附加压重计算公式以及对应的强制合龙成桥后主梁变形方程,并结合工程实例对其进行有限元分析予以验证。施工合龙时所需的附加压重与误差成正比,误差越大对于成桥后主梁的线形影响越大。(5)通过建立强制合龙的数值分析模型,探讨合龙误差对成桥阶段、桥面铺装阶段以及三年徐变后等工况的结构线形影响。成桥后主梁对称截面上的位移变化趋势一致,且随时间增大;合龙误差对成桥阶段的梁体线形影响较大,而在桥面铺装完成后,其影响程度减小,经过三年收缩徐变后,梁体线形变化趋于稳定,而且由合龙误差引起的主梁位移值,不会因混凝土的徐变作用而缓解或消除;通过对先边后中和先中后边两种合龙顺序的对比分析,发现前者强制合龙成桥后梁体线形所受影响为主跨大于边跨,而后者为边跨大于主跨。
[Abstract]:In the construction process of PC continuous beam bridge, it is often necessary to ensure the bridge alignment through construction control. In this paper, taking three-span continuous beam as the engineering background, using Midas / civil to establish the calculation model of bridge structure, aiming at the problems related to temporary consolidation of pier beam in cantilever construction control. The calculation of additional pressure weight and its influence on the structure alignment after completion of the bridge are analyzed and explored. The main work and relevant conclusions are as follows: (1) on the basis of consulting relevant data, understand the development of prestressed concrete continuous beam bridge and the characteristics of cantilever construction, and the temporary consolidation of cantilever construction, The determination of compression weight and the practical measures are discussed. (2) in view of the problems existing in the calculation model of temporary consolidation force analysis, the method of temporary consolidation simulation in the bar system model is studied. On the basis of the calculation and analysis of the stiffness of the temporary consolidation elastic support, the angle stiffness of the main beam is taken as the main parameter, and the temporary consolidation stiffness is discussed. The effect of pier stiffness on the deformation of the main beam in the course of system transformation is shown. The results show that the temporary consolidation is an elastic connection, and the hinge and consolidation are its two limiting states, and when the ratio of stiffness to rotation angle of the pier beam is high, The influence of bridge piers can not be taken into account in the calculation of construction control. (4) based on the analysis of the effect of forced closure engineering measures, the phenomenon of relative height difference between the two ends of the closure section in construction is pointed out. According to the two kinds of closure sequence, the corresponding formulas of additional pressure and weight and the corresponding deformation equation of the main girder after the forced closure of the bridge are derived respectively, and the finite element analysis is carried out to verify the equation in combination with the engineering examples. The additional pressure is proportional to the error, and the greater the error is, the greater the influence of the error on the alignment of the main girder after completion. (5) by establishing the numerical analysis model of forced closure, the stage of bridge completion is discussed. The influence of bridge deck paving stage and three years creep on the structure alignment. After completion of the bridge, the variation trend of the displacement on the symmetrical section of the main beam is consistent and increases with time, and the closure error has a great influence on the beam alignment in the completion stage, but after the completion of the deck pavement, the influence degree decreases, and after three years of shrinkage and creep, The linear variation of beam body tends to be stable, and the displacement value of the main beam caused by the closing error will not be alleviated or eliminated by the creep of concrete. Through the comparative analysis of the sequence of the first edge and the first side and the middle side and the second side, the displacement value of the main beam will not be alleviated or eliminated by the creep action of concrete. It is found that the main span is greater than the side span, while the latter is the edge span larger than the main span.
【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】：U445.4

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