徐变对大跨度钢管混凝土系杆拱桥静力性能的影响研究

发布时间：2018-04-21 13:49

本文选题：徐变 + 钢管混凝土　；参考：《兰州交通大学》2015年硕士论文

【摘要】：钢管混凝土作为一种新型的组合材料,集成了钢管和混凝土的优点,目前在大跨度钢管混凝土系杆拱桥中广泛应用。但是,钢管混凝土徐变与普通混凝土徐变存在一定的差异,钢管混凝土徐变会引起钢管与核心混凝土发生内力重分布,而且在时间荷载下徐变也会对大跨度钢管混凝土系杆拱桥的静力性能产生一定的影响。本文针对钢管混凝土徐变数据较少而且与普通混凝土徐变差异较大,缺乏明确的钢管混凝土徐变计算模型等现状,对钢管混凝土徐变进行了室内试验,并通过试验数据对普通混凝土徐变计算模型进行修正,使其可以应用于钢管混凝土徐变计算,最终用修正后的钢管混凝土徐变计算模型对某大跨度钢管混凝土系杆拱桥进行数值模拟分析,系统的研究了徐变对大跨度钢管混凝土系杆拱桥静力性能的影响。主要研究内容如下:(1)阐述了钢管混凝土发展、特点及其在拱桥中的应用,并简要的介绍了钢管混凝土收缩徐变的特点及其目前国内外的研究现状;(2)在查阅相关文献的基础上,系统的总结了混凝土收缩徐变的基本性质,并简要的介绍了混凝土收缩徐变的影响因素、计算理论和计算模型等;(3)通过不同膨胀剂掺量和含钢率的钢管混凝土试件收缩徐变试验和承载力试验,得到了钢管混凝土徐变曲线和钢管混凝土承载力,分析了不同膨胀剂掺量和含钢率下钢管混凝土收缩徐变变化规律及钢管混凝土的最优膨胀剂掺量;(4)通过最优膨胀剂掺量下的钢管混凝土徐变数据与模拟数值进行对比分析,修正了混凝土徐变计算模型,并将修正后模型的计算结果与实测数据进行对比,证明了该修正模型的合理可靠。(5)以某128m大跨度钢管混凝土系杆拱桥为例,采用Midas-Civil软件建立三维有限元空间模型,用修正后的钢管混凝土徐变计算模型分析了徐变对大跨度钢管混凝土系杆拱桥静力性能的影响,包括拱肋轴力、弯矩、位移以及钢管与核心混凝土应力重分布,系梁弯矩、轴力及位移,吊杆轴力等。
[Abstract]:As a new composite material, concrete-filled steel tube (CFST) integrates the advantages of steel tube and concrete, and is widely used in long-span concrete-filled steel tubular tied arch bridge. However, there are some differences between concrete filled steel tube creep and ordinary concrete creep, and concrete filled steel tube creep will cause the redistribution of internal force between steel tube and core concrete. Moreover, creep under time load will also affect the static behavior of long span concrete-filled steel tubular tied arch bridge. In view of the fact that concrete filled steel tube (CFST) creep data are less and there is a big difference between CFST creep and ordinary concrete creep, the concrete filled steel tube creep calculation model is lacking, so the concrete filled steel tubular creep test is carried out in laboratory. The creep calculation model of ordinary concrete is modified by test data, which can be applied to the creep calculation of concrete-filled steel tube (CFST). Finally, a long-span concrete-filled steel tubular tied arch bridge is numerically simulated with the modified concrete filled steel tube creep model, and the influence of creep on the static behavior of the long-span concrete-filled steel tubular tied arch bridge is systematically studied. The main research contents are as follows: (1) the development and characteristics of concrete-filled steel tubular (CFST) and its application in arch bridges are described, and the characteristics of concrete-filled steel tubular (CFST) shrinkage and creep and the current research situation at home and abroad are briefly introduced. The basic properties of concrete shrinkage and creep are summarized systematically, and the influencing factors of concrete shrinkage and creep are introduced briefly. The creep curve of concrete filled steel tubular (CFST) and the bearing capacity of concrete filled steel tubular (CFST) are obtained by the shrinkage creep test and bearing capacity test of concrete filled steel tube specimens with different amount of expansive agent and steel tube content. The law of shrinkage and creep of concrete-filled steel tube (CFST) under different content of expansive agent and steel content and the optimal quantity of expansive agent of CFST are analyzed. The creep data of CFST under the optimal content of expansive agent are compared with the numerical value of simulation. The calculation model of concrete creep is modified, and the calculated results of the modified model are compared with the measured data. It is proved that the modified model is reasonable and reliable, taking a 128m long span concrete-filled steel tube tied arch bridge as an example. The three-dimensional finite element spatial model is established by using Midas-Civil software. The influence of creep on the static behavior of long-span concrete-filled steel tubular tied arch bridge is analyzed by using the modified creep calculation model of concrete-filled steel tube (CFST), including the axial force and bending moment of arch rib. Displacement and stress redistribution of steel tube and core concrete, bending moment, axial force and displacement, axial force of suspender, etc.
【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】：U441;U448.225

【共引文献】