无应力状态法在混凝土斜拉桥施工控制中的研究

发布时间：2018-05-12 21:36

本文选题：斜拉桥施工控制 + 无应力状态法　；参考：《北京交通大学》2017年硕士论文

【摘要】：混凝土斜拉桥由于施工安装历时时间长,特别是主梁施工采用的是悬臂法时,由于施工进度的原因,主梁混凝土的养护与拆模时间较短,收缩徐变效应将会对主梁的影响更加突出。本文主要研究无应力状态法在预应力混凝土斜拉桥施工控制中的应用,研究无应力状态法对于解决由于混凝土收缩徐变产生的斜拉桥施工控制不闭合现象。文章在结构上主要分为以下四个部分:第一部分介绍了斜拉桥的发展历程以及进展,说明了斜拉桥施工控制的目的、必要性和方法,简单阐述了无应力状态法的发展历程。并且总结归纳了无应力状态法在斜拉桥施工控制中遇到的问题和本文所要解决的问题。第二部分主要研究了混凝土收缩徐变对斜拉桥施工控制中无应力线形、无应力状态量的影响,分别介绍了拉索单元无应力索长和梁塔单元无应力曲率的计算方法,探讨了混凝土收缩徐变效应,从理论方面验算混凝土收缩徐变对无应力状态量的影响,从而间接导致了无应力线形的变化,从而导致了混凝土斜拉桥施工控制的不闭合现象。在本章最后一节根据实际桥梁验证了混凝土收缩徐变对无应力状态量和无应力线形的影响,并由此引出不闭合现象。第三部分先是介绍了不闭合现象,主要将其分为两类:计算不闭合与状态不闭合。对于状态不闭合现象,研究了合龙段强制合龙与自然合龙对斜拉桥内力产生的影响,分析比较两种方法的差异与优略性。对于解决计算不闭合现象,主要对比倒拆-正装法与无应力状态法两种施工控制方法,根据实际桥梁总结两种施工控制依靠迭代消除不闭合现象的原理与步骤,并在本章最后对两种方法进行研究对比,通过对实际算例的计算,比较两种解决不闭合现象的方法的简易性和适用性,通过比较结果比较哪种方法对比合理成桥状态较为精确。第四部分以浙江省南太湖预应力混凝土斜拉桥为工程背景,采用无应力状态法对该桥梁进行了施工监控。验证了考虑收缩徐变效应的迭代分析闭合问题;探讨了无应力正装迭代法在桥梁施工控制中的应用:分阶段施工索力的确定,结构每阶段对应的锚头拔出量,结构线形预拱度的提取,保证现场桥梁施工监控最终达到的目标;最后对桥梁施工控制中的重要参数(如主梁线形,主梁应力;塔顶偏位移,斜拉索索应力)进行了结构参数敏感性分析,根据所得到的结构响应敏感性参数分析总结无应力状态法施工控制过程中敏感性参数变化较大时需要注意的结构响应,保证施工过程中的结构的安全稳定性。
[Abstract]:Due to the long time of construction and installation of concrete cable-stayed bridge, especially the cantilever method is used in the construction of the main beam, because of the construction schedule, the maintenance and dismantling time of the main beam concrete is relatively short. The effect of shrinkage and creep will be more prominent on the main beam. This paper mainly studies the application of the non-stress state method in the construction control of prestressed concrete cable-stayed bridge, and studies the non-stress state method for solving the problem of unclosure of the construction control of the cable-stayed bridge caused by concrete shrinkage and creep. The structure of the paper is divided into four parts: the first part introduces the development and progress of cable-stayed bridge, explains the purpose, necessity and method of construction control of cable-stayed bridge, and simply expounds the development course of stress-free state method. The problems encountered in the construction control of cable-stayed bridges by the stress-free state method and the problems to be solved in this paper are summarized. The second part mainly studies the influence of concrete shrinkage and creep on the unstressed linear and stress-free state in the construction control of cable-stayed bridge, and introduces the calculation methods of the unstressed cable length of the cable element and the stress curvature of the beam tower element, respectively. The effect of shrinkage and creep of concrete is discussed. The influence of shrinkage and creep of concrete on the quantity of unstressed state is calculated theoretically, which indirectly leads to the change of linear shape of stress free and leads to the unclosed phenomenon of construction control of concrete cable-stayed bridge. In the last section of this chapter, the effect of concrete shrinkage and creep on the unstressed state and the stress-free linear shape is verified according to the actual bridge, and the phenomenon of unclosure is induced. The third part introduces the phenomenon of unclosure, which is divided into two categories: computational unclosure and state unclosure. The influence of forced closure and natural closure on the internal force of cable-stayed bridge is studied and the differences and advantages of the two methods are analyzed and compared. In order to solve the problem of calculation unclosure, this paper mainly compares two construction control methods, the inverted disassembly method and the non-stress state method. According to the actual bridge, the principle and steps of the two construction control methods to eliminate the unclosed phenomenon by iteration are summarized. At the end of this chapter, the two methods are studied and compared. Through the calculation of practical examples, the simplicity and applicability of the two methods to solve the unclosed phenomenon are compared, and the comparison of the results of the two methods is more accurate than that of the reasonable bridge state. The fourth part takes the prestressed concrete cable-stayed bridge of South Taihu Lake in Zhejiang Province as the engineering background and uses the method of non-stress state to monitor the construction of the bridge. This paper verifies the closure problem of iterative analysis considering shrinkage and creep effect, and discusses the application of non-stress formal iteration method in bridge construction control, including the determination of cable force in stages of construction, the pull out amount of anchor head corresponding to each stage of the structure, The extraction of the pre-camber of the structure to ensure the final goal of the field bridge construction monitoring and control; finally, the important parameters in the bridge construction control (such as the main beam shape, the stress of the main beam, the displacement of the tower top, etc. The sensitivity analysis of structural parameters is carried out. According to the structural response sensitivity parameters obtained, the structural responses which should be paid attention to when the sensitivity parameters change greatly in the construction control process of the stress-free state method are summarized. Ensure the safety and stability of the structure during construction.
【学位授予单位】：北京交通大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：U445.4

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