剪力钉集束式与均布式布置下钢—混组合梁桥受力分析

发布时间：2018-04-02 17:27

本文选题：剪力钉　切入点：集束式　出处：《武汉理工大学》2014年硕士论文

【摘要】：钢-混组合梁桥是通过剪力钉连接混凝土桥面板与钢主梁。目前剪力钉布置方式主要采用均布式，其剪力钉受力具有比较均匀的特征，但是也造成混凝土桥面板必须预制施工，引起不便。港珠澳大桥钢-混组合连续箱梁的剪力钉采用了新颖的集束式布置方式，它可以对桥面板进行分块预制整体拼装，具有施工速度快、安装质量好的特点。但是，剪力钉集束式布置对钢-混组合梁桥整体受力性能的影响和剪力钉的受力性能成为桥梁设计人员非常关心的问题。据此，开展剪力钉集束式和均布式布置下钢-混组合梁桥受力特性分析研究，对掌握钢-混组合梁桥的设计方法和营运性能具有重要的理论意义。本文针对港珠澳大桥非通航孔6×85m组合连续梁桥开展受力性能分析，采用生死单元法模拟港珠澳大桥的实际施工过程，即大节段整体吊装、简支变连续、支点顶升与回落、支点纵向预应力张拉以及二期恒载的全过程。按照剪力钉集束式布置和剪力钉均布式布置两种方式，分别计算了钢-混组合梁桥受力性能和剪力钉的受力状况，为钢-混组合梁桥剪力钉集束式布置提供分析依据。研究主要内容和成果如下： (1)剪力钉集束分布和均匀分布单跨精细子模型选取全桥模型中剪力钉受力最不利的85m边跨，以全桥模型切割边界上的位移作为精细模型的边界条件。剪力钉采用BEAM188梁单元模拟，程序中直接输入剪力钉的截面、弹性模量和泊松比等材料性质，避免了弹簧单元剪切刚度不稳定的缺点，以准确计算出每个剪力钉的纵向剪力、横向剪力和拉拔力。 (2)在成桥阶段恒载和最不利活载作用下，剪力钉集束分布与均匀分布时组合梁的挠度、混凝土桥面板应力以及钢梁应力基本相同。对比剪力钉集束分布与均匀分布分别在恒载、最不利活载、收缩、升温和降温下剪力钉的受力，得到剪力钉均匀分布比集束分布受力更均匀，但最大值差别不大。 (3)对集束分布和均匀分布下纵向剪力和拉拔力最大位置剪力钉分别进行强度验算，得到两种分布形式下剪力钉受力都在使用状态承载力范围内，满足正常使用要求。考虑到当剪力钉采用集束布置时混凝土桥面板可以采用预制施工，相比现浇桥面板施工，预制混凝土桥面板施工的方法在经济性、施工性、工期方面都有很大的优势，因此剪力钉集束分布方案值得推广。
[Abstract]:Steel-concrete composite beam bridge connects concrete deck slab with steel main beam by shear nail.At present, the arrangement of shear nails mainly adopts the uniform distribution type, and the shear nail has the characteristic of uniform force, but it also causes the precast construction of concrete bridge deck, which causes inconvenience.The shear nail of the steel-mixed composite continuous box girder of Hongkong-Zhuhai-Macao Bridge adopts a novel cluster arrangement. It can be used to assemble the deck of the bridge by block prefabrication and integral assembly, which has the characteristics of fast construction speed and good installation quality.However, the influence of shear nail cluster arrangement on the overall mechanical behavior of steel-concrete composite beam bridge and the mechanical behavior of shear nail have become a problem of great concern to bridge designers.Therefore, it is of great theoretical significance to analyze and study the mechanical characteristics of steel-concrete composite beam bridge under shear nail cluster and uniform arrangement, which is of great theoretical significance for mastering the design method and operation performance of steel-concrete composite beam bridge.In this paper, according to the mechanical performance analysis of 6 脳 85m composite continuous girder bridge with non-navigable holes, the actual construction process of the bridge is simulated by using the birth and death element method, that is, the whole lifting of large segment, the change of simple support to continuous, the uplift and fall of fulcrum.The whole process of longitudinal prestressing tension of fulcrum and the second stage dead load.According to the two types of shear nail cluster arrangement and shear nail uniform arrangement, the mechanical behavior and shear nail force condition of steel-concrete composite beam bridge are calculated respectively, which provides the basis for the analysis of the shear nail cluster arrangement of steel-concrete composite beam bridge.The main contents and results of the study are as follows:1) the single span fine submodel of shear nail cluster distribution and uniform distribution selects 85 m edge span which is the most unfavorable shear nail force in the whole bridge model. The displacement on the cutting boundary of the whole bridge model is taken as the boundary condition of the fine model.The shear nail is simulated by BEAM188 beam element. The material properties such as section, modulus of elasticity and Poisson's ratio are directly input into the program, which avoids the disadvantage of unstable shear stiffness of spring element, so as to accurately calculate the longitudinal shear force of each shear nail.Transverse shear and drawing force.(2) under the action of dead load and most unfavorable live load, the deflection of composite beam, the stress of concrete deck slab and the stress of steel beam are basically the same when the distribution of shear nail cluster is equal to that of uniform distribution.Compared with the uniform distribution of shear nail under dead load, most unfavorable live load, shrinkage, heating and cooling, it is found that the uniform distribution of shear nail is more uniform than that of cluster distribution, but the maximum value is not different.3) the strength of the maximum position shear nail of longitudinal shear force and drawing force under cluster distribution and uniform distribution is calculated separately, and the results show that the shear nail force is in the range of service state bearing capacity under the two distribution forms, which meets the requirements of normal use.Considering that precast construction can be used for concrete deck slab when shear nail is arranged by cluster, the construction method of precast concrete deck slab has great advantages in economy, constructability and time limit, compared with that of cast-in-place deck slab construction.Therefore, the scheme of shear nail cluster distribution is worth popularizing.
【学位授予单位】：武汉理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：U441

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