钢—混凝土组合梁收缩应力计算及测量方法研究
发布时间：2018-10-18 14:02
【摘要】：钢-混凝土组合梁能够充分发挥两种材料的优势并限制其劣势,提高结构的承载力、刚度和延性等性能。但混凝土的收缩、徐变会导致结构产生复杂的长期效应,包括不同材料间的截面应力重分布、超静定结构的内力重分布以及组合梁中的附加变形。通常情况下,长期效应引起的组合梁附加内力会导致混凝土受拉,钢结构受压,对结构产生不利的影响。因此,合理预测并评估组合梁的长期效应,对于确保结构的安全性并提高计算分析方法的准确性具有重要意义。针对现有方法不能合理反映组合梁翼板内混凝土收缩应力的空间分布特征,以及缺少有效的混凝土收缩应力测试方法等问题,本论文重点研究了收缩应力的分析方法和测试方法,主要工作和成果包括:(1)通过文献调研总结出混凝土的长期材料特性以及其用于力学计算时采用的方法。其中,主要考虑的混凝土材料长期性能为混凝土硬化过程中的弹性模量发展、混凝土收缩以及由收缩应力引起的次生徐变效应。(2)为了对研究问题进行简化,明确分析对象为一简支组合梁,并在现有方法的基础上,进一步考虑混凝土板宽度对收缩应力大小的影响,利用组合结构中常用的有效宽度的概念,提出改进的计算方法,并将该方法与有限元对比验证其准确性。如有必要,可以利用有限元结果对理论分析方法进行修正。(3)根据以上提出的方法,设定参数,对一个具体算例进行附加内力和应力的分析,为工程中应用提供参考。(4)设计试验,对组合梁内部应力的测量方法进行研究。收缩徐变引起的组合梁内部应力难以通过传统测量方法测出,因此本文中通过文献调研找出测量该应力的有效方法,并设计试验加以验证。同时建立有限元模型与试验进行对比,为进一步的组合梁内部附加应力的测量打下基础。本论文最后提出一种定量计算混凝土收缩徐变性能对组合梁内力影响的计算方法,并应用于工程实践。
[Abstract]:Steel-concrete composite beams can give full play to the advantages and disadvantages of the two materials, and improve the bearing capacity, stiffness and ductility of the structure. However, the shrinkage and creep of concrete will lead to complex long-term effects, including the redistribution of cross-section stress between different materials, the redistribution of internal force of statically indeterminate structures and the additional deformation in composite beams. In general, the additional internal force of composite beam caused by long-term effect will lead to concrete tension and steel structure compression, which will have a negative effect on the structure. Therefore, it is of great significance to predict and evaluate the long-term effect of composite beam reasonably in order to ensure the safety of structure and improve the accuracy of calculation and analysis method. The existing methods can not reasonably reflect the spatial distribution characteristics of concrete shrinkage stress in the flange of composite beam and the lack of effective concrete shrinkage stress measurement method. This paper focuses on the analysis and measurement of shrinkage stress. The main work and results are as follows: (1) the long-term material characteristics of concrete and the methods used in mechanical calculation are summarized through literature research. Among them, the long-term properties of concrete are the development of elastic modulus in the process of concrete hardening, the shrinkage of concrete and the secondary creep effect caused by shrinkage stress. (2) in order to simplify the research, The object of analysis is a simply supported composite beam. On the basis of the existing methods, the influence of the width of concrete slab on the shrinkage stress is further considered. Using the concept of effective width commonly used in the composite structure, an improved calculation method is put forward. The accuracy of the method is verified by comparing it with finite element method. If necessary, the finite element results can be used to modify the theoretical analysis method. (3) according to the above method, the parameters are set, and the additional internal force and stress are analyzed for a concrete example. (4) Design test. The measurement method of internal stress of composite beam is studied. The internal stress of composite beam caused by shrinkage and creep is difficult to be measured by the traditional measurement method, so the effective method of measuring the stress is found out by literature investigation in this paper, and the experiment is designed to verify it. At the same time, the finite element model is established and compared with the test, which lays the foundation for the further measurement of the additional stress in the composite beam. In the end of this paper, a quantitative method for calculating the effect of shrinkage and creep behavior of concrete on the internal force of composite beam is proposed and applied to engineering practice.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU398.9
[Abstract]:Steel-concrete composite beams can give full play to the advantages and disadvantages of the two materials, and improve the bearing capacity, stiffness and ductility of the structure. However, the shrinkage and creep of concrete will lead to complex long-term effects, including the redistribution of cross-section stress between different materials, the redistribution of internal force of statically indeterminate structures and the additional deformation in composite beams. In general, the additional internal force of composite beam caused by long-term effect will lead to concrete tension and steel structure compression, which will have a negative effect on the structure. Therefore, it is of great significance to predict and evaluate the long-term effect of composite beam reasonably in order to ensure the safety of structure and improve the accuracy of calculation and analysis method. The existing methods can not reasonably reflect the spatial distribution characteristics of concrete shrinkage stress in the flange of composite beam and the lack of effective concrete shrinkage stress measurement method. This paper focuses on the analysis and measurement of shrinkage stress. The main work and results are as follows: (1) the long-term material characteristics of concrete and the methods used in mechanical calculation are summarized through literature research. Among them, the long-term properties of concrete are the development of elastic modulus in the process of concrete hardening, the shrinkage of concrete and the secondary creep effect caused by shrinkage stress. (2) in order to simplify the research, The object of analysis is a simply supported composite beam. On the basis of the existing methods, the influence of the width of concrete slab on the shrinkage stress is further considered. Using the concept of effective width commonly used in the composite structure, an improved calculation method is put forward. The accuracy of the method is verified by comparing it with finite element method. If necessary, the finite element results can be used to modify the theoretical analysis method. (3) according to the above method, the parameters are set, and the additional internal force and stress are analyzed for a concrete example. (4) Design test. The measurement method of internal stress of composite beam is studied. The internal stress of composite beam caused by shrinkage and creep is difficult to be measured by the traditional measurement method, so the effective method of measuring the stress is found out by literature investigation in this paper, and the experiment is designed to verify it. At the same time, the finite element model is established and compared with the test, which lays the foundation for the further measurement of the additional stress in the composite beam. In the end of this paper, a quantitative method for calculating the effect of shrinkage and creep behavior of concrete on the internal force of composite beam is proposed and applied to engineering practice.
【学位授予单位】：清华大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU398.9
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