轴向约束钢筋混凝土短柱高温下力学性能试验研究

发布时间：2018-05-14 09:18

本文选题：钢筋混凝土 + 约束方式　；参考：《湘潭大学》2017年硕士论文

【摘要】：结构抗火是结构工程领域里一个重要的研究课题。目前对火灾作用下钢筋混凝土力学性能的研究较多,但考虑初始荷载影响的并不多,且大部分研究所采用的试件尺寸较小,尺寸效应将导致构件在高温时产生明显的不均匀温度场,这将直接影响火灾作用下钢筋混凝土构件的力学性能。目前国内外的混凝土抗火研究大都没有考虑相邻构件的影响,而在实际火灾中,由于相邻构件间存在相互约束作用,当某个构件受到火灾作用时,会受到相邻构件的约束,其抗火性能必然与单个构件受火的情况有所不同。为此,本文开展了受轴力及刚度约束的较大尺寸钢筋混凝土短柱经历ISO-834标准火灾升降温作用后的轴压力学性能试验研究,具体内容如下:(1)采用ABAQUS有限元分析软件对钢筋混凝土短柱经历ISO-834标准火灾作用的截面温度场分布进行分析,并通过3个钢筋混凝土短柱的温度场试验验证有限元分析模型的可靠性。(2)开展21个经历ISO-834标准火灾升降温作用的钢筋混凝土短柱轴压力学性能试验,主要考察了约束方式、升降温时间和轴压比对混凝土短柱高温下变形、剩余承载力、轴压刚度的影响。(3)采用高温下钢筋和混凝土的强度、弹性模量的损伤模型以及应力-应变关系模型,计算了高温下钢筋混凝土短柱的剩余承载力、剩余轴压刚度以及荷载-轴向变形关系。再将本文试验结果与理论分析以及相关试验结果进行对比,分析轴压比、升降温制度对高温下钢筋混凝土短柱的承载力、轴压刚度以及荷载-轴向变形关系的影响。
[Abstract]:Structural fire resistance is an important research topic in the field of structural engineering. At present, there are many researches on the mechanical properties of reinforced concrete under fire, but the effect of initial load is not much, and the size of the specimens used in most of the studies is small. The size effect will lead to the obvious inhomogeneous temperature field at high temperature, which will directly affect the mechanical properties of reinforced concrete members under fire. At present, the research of concrete fire resistance at home and abroad has not considered the influence of adjacent members, but in the actual fire, because of the interaction between adjacent members, when a member is affected by fire, it will be constrained by adjacent members. Its fire resistance must be different from that of a single member. Therefore, an experimental study on the axial compression mechanical properties of large reinforced concrete short columns subjected to ISO-834 standard fire was carried out in this paper, which was constrained by axial force and stiffness. The specific contents are as follows: (1) using ABAQUS finite element analysis software, the section temperature field distribution of reinforced concrete short columns subjected to ISO-834 standard fire is analyzed. The reliability of the finite element analysis model is verified by the temperature field test of three reinforced concrete short columns. The reliability of the finite element analysis model is verified. 21 tests on the axial compressive mechanical properties of the reinforced concrete short columns which have experienced the effect of ISO-834 standard fire rise and cooling are carried out, and the restraint mode is mainly investigated. The influence of deformation, residual bearing capacity and axial compression stiffness of short concrete columns under high temperature, such as rising and cooling time and axial compression ratio. The damage model of strength, elastic modulus and stress-strain relationship model of steel bar and concrete under high temperature is adopted. The residual bearing capacity, residual axial compression stiffness and load-axial deformation relationship of reinforced concrete short columns at high temperature are calculated. Then the experimental results of this paper are compared with the theoretical analysis and related test results, and the influence of axial compression ratio, temperature rise and cooling system on the bearing capacity, axial compression stiffness and load-axial deformation relationship of reinforced concrete short columns under high temperature is analyzed.
【学位授予单位】：湘潭大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU375.3

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