火灾（高温）后型钢再生混凝土柱力学性能试验研究及理论分析

发布时间：2019-04-03 19:08

【摘要】：型钢再生混凝土结构(简称SRRAC)充分发挥了型钢混凝土与再生混凝土的优点,不仅承载力高、刚度大、抗震性能好,并且节能、环保、可持续,应用前景广阔。目前,对于火灾后SRRAC结构的性能劣化机理与评估理论,国内外文献尚属空白,相关研究十分必要且意义重大。本文综合运用试验研究、数值模拟及理论分析等手段,对火灾后SRRAC柱的力学性能进行深入研究：首先,对再生混凝土和钢材两种材料进行不同火灾高温后的力学性能测试,获取了两种材料的物理及力学性能指标,得到高温后再生混凝土及钢材力学性能随温度的退化规律；并提出了高温后再生混凝土残余抗压强度的计算公式。其次,以再生骨料取代率、高温温度、恒温时间、型钢保护层厚度、偏心率、配钢和配箍形式为变化参数,设计54个SRRAC柱试件进行火灾(高温)后的力学性能试验(其中轴压试件48个,偏压试件6个)。获取了试件火灾后的烧失量,提出了根据烧失量对SRRAC构件所经历最高温度的估算方法。通过试验,观察了试件的破坏过程与形态,揭示了其截面受力特点及破坏机理,分析了其荷载-变形特征、截面应变分布、剩余承载力、刚度、损伤和延性等力学性能及其退化规律。结果表明,火灾高温后SRRAC柱的承载力及刚度有所降低,延性及损伤有所增大；力学性能的退化规律主要受到最高温度、恒温时间、偏心率和型钢保护层厚度等参数的影响。此外,采用ABAQUS有限元软件对火灾下SRRAC柱的瞬态温度场进行数值计算,分析了截面温度场的影响因素。结果表明,最高受火温度、恒温时间和型钢保护层厚度对截面温度场的分布有较大影响。最后,综合试验研究与数值模拟分析结果,在充分考虑火灾后SRRAC柱截面力学特点以及构件正截面承载力计算特殊性的基础上。采用等效截面和强度折减的方法提出了火灾(高温)后SRRAC柱轴心受压及偏心受压的正截面承载力计算公式,计算结果与试验结果吻合较好。并且,在此基础上对火灾后SRRAC结构的评定方法进行了初探。
[Abstract]:Section steel recycled concrete structure (SRRAC) gives full play to the advantages of steel reinforced concrete (SRC) and recycled concrete (RRC). It not only has high bearing capacity, high stiffness, good seismic performance, but also has the advantages of energy saving, environmental protection, sustainability and wide application prospect. At present, for the mechanism of performance degradation and evaluation theory of SRRAC structure after fire, the literature at home and abroad is still blank, and the related research is very necessary and significant. In this paper, the mechanical properties of SRRAC columns after fire are studied by means of experimental research, numerical simulation and theoretical analysis. The mechanical properties of recycled concrete and steel after high temperature fire were tested and the physical and mechanical properties of the two materials were obtained. The degradation of mechanical properties of recycled concrete and steel after high temperature was obtained. A formula for calculating the residual compressive strength of recycled concrete after high temperature is proposed. Secondly, the replacement rate of recycled aggregate, high temperature, constant temperature time, thickness of protective layer of section steel, eccentricity, steel matching and hoop form are taken as the changing parameters. Fifty-four SRRAC column specimens were designed to test their mechanical properties after fire (high temperature) (including 48 axial compression specimens and 6 bias compression specimens). The burn loss of the specimen after fire is obtained, and the estimation method of the maximum temperature of the SRRAC component is put forward according to the amount of the burn loss. Through the test, the failure process and shape of the specimen are observed, the stress characteristics and failure mechanism of the section are revealed, the load-deformation characteristics, the strain distribution of the cross-section, the residual bearing capacity and the stiffness of the specimen are analyzed. Mechanical properties such as damage and ductility and their degradation law. The results show that the bearing capacity and stiffness of SRRAC columns decrease and the ductility and damage increase after high temperature fire, and the degradation rule of mechanical properties is mainly influenced by the parameters such as maximum temperature, constant temperature time, eccentricity and thickness of protective layer of section steel. In addition, the ABAQUS finite element software is used to calculate the transient temperature field of the SRRAC column under fire, and the influence factors of the cross-section temperature field are analyzed. The results show that the maximum fire temperature, the constant temperature time and the thickness of section steel cover have great influence on the distribution of section temperature field. Finally, comprehensive experimental research and numerical simulation analysis results, on the basis of fully considering the mechanical characteristics of the SRRAC column section after fire and the particularity of the calculation of the bearing capacity of the normal section of the member. Using the method of equivalent section and strength reduction, the formulas of bearing capacity of normal section of SRRAC column subjected to axial compression and eccentric compression after fire (high temperature) are put forward. The calculated results are in good agreement with the experimental results. On this basis, the evaluation method of SRRAC structure after fire is discussed.
【学位授予单位】：广西大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU398.9

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