钢管混凝土收缩徐变性能研究

发布时间：2018-02-26 13:45

本文关键词： 钢管混凝土收缩试验徐变试验徐变系数有限元分析　出处：《西南交通大学》2016年硕士论文　论文类型：学位论文

【摘要】：随着钢管混凝土在高层建筑、大跨度桥梁中的使用越来越多,由混凝土的收缩徐变而引起的结构挠度变化、体系转换后的内力重分布等问题日益突出,将影响到钢管混凝土结构的长期使用性能,因此,钢管混凝土的收缩徐变问题已成为工程设计中不可忽视的因素。钢管混凝土构件由于核心混凝土处在钢管内部,其核心混凝土与外界没有空气接触,核心混凝土收缩量基本可以忽略不计。钢管混凝土构件中核心混凝土和钢管的相互作用比较复杂,核心混凝土处于三向应力状态核心混凝土徐变引起的内力重分布问题比普通混凝土更为复杂。因而对钢管混凝土构件的收缩徐变研究十分必要。本文依托北盘江大桥为背景,在施工现场对素混凝土和钢管混凝土的长期性能做了对比试验,得出钢管混凝土的收缩徐变规律,并且对素混凝土试验数据进行了拟合。由于钢管混凝土中核心混凝土和钢管复杂的相互作用,为考察钢管和核心混凝土相互作用和局部效应,提出了一种单轴钢管混凝土结构徐变的直接计算方法和两种钢管混凝土结构徐变的有限元计算方法：(1)不考虑加载龄期的影响,根据钢管和核心混凝土的变形协调条件,利用龄期调整的有效模量法推导出钢管混凝土徐变变形和时间的关系；(2)考虑加载龄期的影响,通过把时间t划分为一系列时段,需要存储应力历史,通过叠加各个时间段徐变系数和应变分量乘积,利用通用有限元软件ANSYS计算得到最后时刻的徐变应变；(3)利用龄期调整的有效模量法推导出任意时间点的应力应变关系,将徐变转化为弹性变形,计算任意时间点的徐变变形。本文通过通用有限元软件ANSYS提供的参数化设计语言(APDL),可以实现钢管混凝土徐变的有限元求解。还研究了含钢率对钢管混凝土徐变的影响。同时也用MIDAS CIVIL建立劲性骨架钢管混凝土全桥有限元模型进行施工阶段仿真分析。
[Abstract]:With the increasing use of concrete-filled steel tube (CFST) in high-rise buildings, the structural deflection caused by shrinkage and creep of concrete and the redistribution of internal force after system conversion become more and more serious. Therefore, the shrinkage and creep of concrete-filled steel tube (CFST) has become an important factor in engineering design. The core concrete has no air contact with the outside world, and the shrinkage of the core concrete can be neglected basically. The interaction between the core concrete and the steel tube in the concrete filled steel tube member is quite complex. The internal force redistribution caused by core concrete creep is more complex than that of ordinary concrete, so it is necessary to study the shrinkage and creep of concrete-filled steel tube members. The long-term performance of plain concrete and concrete-filled steel tube (CFST) is compared with that of concrete filled steel tube (CFST) in the construction site, and the law of shrinkage and creep of CFST is obtained. The experimental data of plain concrete are fitted. Because of the complex interaction between the core concrete and the steel tube in concrete filled steel tube, the interaction and local effect between the core concrete and the steel tube are investigated. A direct calculation method for creep of concrete filled steel tube (CFST) structure with uniaxial axis and two finite element methods for calculating creep of concrete filled steel tubular structure (CFST) are presented. The influence of loading age is not considered, according to the deformation coordination condition between steel tube and core concrete. The relationship between creep deformation and time of concrete-filled steel tube (CFST) is deduced by using the effective modulus method of age adjustment. The influence of loading age is considered. By dividing time t into a series of periods, the stress history needs to be stored. By superposing the product of creep coefficient and strain component in each time period and using the universal finite element software ANSYS to calculate the creep strain at the last moment, the stress-strain relationship at any time point is deduced by using the effective modulus method of age adjustment. Turning creep into elastic deformation, The creep deformation at any time point is calculated. In this paper, the finite element solution of concrete filled steel tube creep can be realized by using the parametric design language provided by the general finite element software ANSYS. The effect of steel content ratio on the creep of concrete filled steel tube is also studied. At the same time, MIDAS CIVIL is used to establish the finite element model of the steel tubular concrete filled steel tube (CFST) bridge.
【学位授予单位】：西南交通大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU398.9

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