钢管混凝土收缩徐变及其对系杆拱桥力学性能影响研究

发布时间：2018-06-17 19:03

本文选题：系杆拱桥 + 钢管混凝土　；参考：《兰州交通大学》2014年博士论文

【摘要】：钢管混凝土作为钢管和混凝土两种材料的最佳组合,广泛应用在土木工程结构中。本文结合目前钢管混凝土研究现状,针对钢管混凝土徐变试验数据和现场数据较少、机理研究不足等方面存在的问题,采用试验研究、理论分析、数值模拟及现场试验相结合的方法,系统地研究了钢管混凝土收缩徐变机理及其对钢管混凝土系杆拱桥受力性能的影响。主要研究工作如下:(1)在查阅大量国内外文献的基础上,系统的总结了钢管混凝土收缩徐变试验研究、理论分析、数值计算、现场研究等方面的现状。(2)以核心混凝土为研究对象,进行限制膨胀和收缩的试件试验,同时采用自制试验模型测试核心混凝土在不同外加剂、不同养护方式下的收缩性能变化情况。(3)通过3年收缩徐变试验,共进行51根钢管混凝土柱徐变试验和11根钢管混凝土柱收缩试验。通过不同含钢率、应力比和膨胀剂掺量的试验,分析不同影响因素下,钢管混凝土收缩徐变性能变化规律。在试验的基础上,得出与试验结果匹配的收缩徐变的数学模型。(4)对核心混凝土进行了SEM扫描电镜、RapidAir孔结构分析,从微观角度分析钢管混凝土在不同膨胀剂掺量、不同养护方式条件核心混凝土徐变机理。从微观形貌和孔结构上论证钢管混凝土宏观收缩徐变的内在原因,进一步完善了钢管混凝土收缩徐变机理。(5)以一实际结构为例,通过数值模拟的方法,分析不同国家规范在计算收缩徐变方面的差异性,同时分析了系杆拱桥在不同徐变模式下,拱肋、吊杆及系梁的内力、挠度变化情况,定量地得到了徐变对系杆拱桥的影响程度。(6)进行了现场钢管混凝土拱肋在不同的徐变模式作用下,核心混凝土和钢管各自的应力变化测试与分析,定量地分析了内力重分布和应力松弛。
[Abstract]:As the best combination of steel tube and concrete, concrete-filled steel tube (CFST) is widely used in civil engineering structures. According to the present research situation of concrete-filled steel tubular (CFST), this paper uses experimental research and theoretical analysis to solve the problems existing in concrete filled steel tubular concrete (CFST) creep test data and field data, and the insufficient research on mechanism, etc. The mechanism of shrinkage and creep of concrete-filled steel tubular (CFST) and its influence on the mechanical behavior of concrete-filled steel tubular tied arch bridge are systematically studied by means of numerical simulation and field test. The main research work is as follows: (1) on the basis of consulting a large number of domestic and foreign documents, the paper systematically summarizes the present situation of concrete filled steel tube (CFST) shrinkage and creep test research, theoretical analysis, numerical calculation, field research, etc.) taking the core concrete as the research object, The shrinkage behavior of the core concrete under different admixtures and different curing methods was tested by self-made test model, and the shrinkage creep test was carried out for 3 years. A total of 51 concrete filled steel tubular columns were tested by creep test and 11 concrete filled steel tubular columns were subjected to shrinkage tests. Through the tests of different steel content, stress ratio and expansion agent content, the change law of shrinkage and creep behavior of concrete-filled steel tube (CFST) was analyzed under different influence factors. On the basis of the experiment, the mathematical model of shrinkage and creep matching with the test results is obtained. The structure of the core concrete is analyzed by SEM scanning electron microscope and RapidAir pore structure, and the content of concrete filled steel tube in different expansion agent is analyzed from the microscopic point of view. Creep mechanism of core concrete under different curing conditions. The internal causes of macroscopic shrinkage and creep of concrete-filled steel tubular (CFST) are demonstrated from the microscopic morphology and pore structure, and the mechanism of shrinkage and creep of CFST is further improved. Taking a practical structure as an example, the method of numerical simulation is used. The differences in calculating shrinkage and creep of different national codes are analyzed, and the internal forces and deflection of arch ribs, suspenders and girders in different creep modes of tied arch bridges are analyzed. The degree of influence of creep on tied arch bridge is obtained quantitatively. The stress changes of core concrete and steel tube are tested and analyzed respectively under different creep modes of concrete filled steel tube arch rib in situ. The redistribution of internal force and stress relaxation are quantitatively analyzed.
【学位授予单位】：兰州交通大学
【学位级别】：博士
【学位授予年份】：2014
【分类号】：U441;U448.225

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