混凝土箱梁桥变截面移动模架关键技术研究

发布时间：2018-05-25 09:40

本文选题：变截面移动模架 + 受力分析　；参考：《长安大学》2015年硕士论文

【摘要】：移动模架工法施工优点突出,如标准化操作后期容易熟练操作、施工循环时间短,箱梁结构整体性好,重复利用率高、经济合理,对地基要求低,对桥下通航以及通车影响较小等等,移动模架工法的广泛应用得益于以上诸多优势,尤其在城市高架、高墩桥梁的施工中更能体现其突出于其它工艺的优势。但是,就当前的工程实践而言,移动模架工法在受力、经济性、施工工艺、施工监测方面仍然存在诸多不足,以变截面移动模架施工工艺的问题上尤为突出。另外,移动模架施工中也出现过重大安全事故,这些问题严重制约了移动模架在中小跨径大长桥施工中的推广和应用。本文针对移动模架工法的应用现状,以泉州湾跨海大桥为工程背景,围绕“移动模架的受力分析、施工关键技术及施工监测”,通过搜集整理大量的文献资料,对移动模架工法特点及适用性,仿真模拟,施工工艺及关键技术,施工监测等等一些问题进行相关研究,通过学习研究,获得一些有实际意义的结论与创新:(1)在既有移动模架的设计、工程应用的基础之上,做了关于移动模架工法的构造形式、特点、适用性以及与其它工法优势的对比。提出了应用移动模架施工的箱梁桥施工的桥梁的设计要求和移动模架工法施工的合理性。(2)结合钢结构相关设计理论和有关规范,运用有限元软件MIDAS CIVIL对移动模架主要受力结构主梁、鼻梁、牛腿进行了仿真分析计算,得到结论:牛腿及其增设的支架系统应力较为集中,比较靠近Q345钢材的设计应力,预示到这些部位的钢材在最不利荷载作用下容易趋向于塑性工作状态。主梁在浇筑状态、鼻梁在行走状态过程中构件应力储备较大,满足设计要求。(3)通过其施工工艺流程和步骤、等截面与变截面移动模架施工工法在主体结构及流程上的对比,移动模架的拼装、调试,模架主体结构调整难点,混凝土浇筑顺序等关键技术进行研究,提出了移动模架施工桥梁新旧混凝土结合部的错台防制措施。并对渐变段施工模架结构的安全控制和主梁的线形控制等技术难题做了总结。(4)论述了移动模架的施工监测,主要是对移动模架应力、梁体线形监测做了详细研究,针对移动模架在行走状态和梁体混凝土浇筑状态过程中模架关键监测部位的应力值,混凝土浇筑状态的梁体高程与理论计算值进行对比,推断其在工程实践中的安全储备,评估其工作性能,为移动模架法在实际施工中提供预警及安全保障。
[Abstract]:The construction method of moving mould frame has outstanding advantages, such as easy and skilled operation in the later stage of standardized operation, short construction cycle time, good integrity of box girder structure, high reuse rate, reasonable economy and low requirement for foundation. The wide application of the method of moving mould frame can benefit from the advantages above, especially in the construction of urban elevated bridge and high pier bridge. However, as far as the current engineering practice is concerned, there are still many deficiencies in the construction technology, such as force, economy, construction technology and construction monitoring, especially in the construction technology of variable cross section moving die frame. In addition, there have been major safety accidents in the construction of the movable formwork frame, which seriously restricts the popularization and application of the mobile formwork frame in the construction of medium and small span long bridge. In view of the present situation of the application of the moving mould frame method, taking Quanzhou Bay Bridge across the sea as the engineering background, this paper focuses on the "force analysis, key construction technology and construction monitoring of the moving mould frame", and through collecting and sorting out a large number of documents and materials. The characteristics and applicability, simulation, construction technology and key technology, construction monitoring and so on are studied. On the basis of the design and engineering application of the existing mobile die frame, this paper makes a comparison of the construction form, characteristics, applicability and advantages with other methods. The design requirements of the bridge in the construction of the box girder bridge by using the moving formwork frame and the rationality of the construction of the moving formwork frame are put forward, combining with the relevant design theory of the steel structure and the relevant specifications. The finite element software MIDAS CIVIL is used to simulate and calculate the main beam, nose beam and leg of the main force structure of the moving mould frame. The conclusion is that the stress of the leg and its additional support system is relatively concentrated, which is close to the design stress of Q345 steel. It indicates that the steels in these parts tend to work in plastic state under the most unfavorable load. In the pouring state of the main beam, the stress reserve of the members of the nose beam in the course of walking is large, which meets the design requirements. Through its construction process and steps, the construction method of the moving die frame with equal section and variable section is compared in the main structure and the flow. The key technologies such as assembling, debugging, adjusting the main structure of the mould frame, and the pouring sequence of concrete are studied, and the measures of preventing and controlling the new and old concrete joint of the new and old concrete in the construction of the moving mould frame are put forward. In addition, the paper summarizes the technical problems such as the safety control of the construction die frame structure and the linear control of the main beam, and discusses the construction monitoring of the moving die frame, which mainly studies the stress of the moving die frame and the monitoring of the line shape of the beam body in detail. According to the stress value of the key monitoring part of the mould frame in the walking state and the concrete pouring state of the beam, the height of the beam body in the concrete pouring state is compared with the theoretical calculation value, and its safety reserve in engineering practice is inferred. Its working performance is evaluated to provide early warning and safety guarantee for moving mould frame method in actual construction.
【学位授予单位】：长安大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：U448.213;U445.463

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