地震火灾后钢筋混凝土柱的抗震性能研究

发布时间：2018-04-24 20:20

本文选题：钢筋混凝土柱 + 抗火性能　；参考：《湖南大学》2015年硕士论文

【摘要】：近年来频频发生的建筑火灾事故造成了巨大的经济损失,更夺走了许多宝贵的生命,为了减少甚至防止此类悲剧的再次发生,钢筋混凝土柱作为混凝土结构的主要承重构件之一,其抗火性能研究十分重要。本文通过大量文献调查,根据国内外的研究成果对钢筋混凝土柱的抗火性能包括耐火极限和火灾后的受力性能进行了综述。通过对526个试件试验数据的统计分析,确定了钢筋混凝土柱抗火性能的影响因素包括：(1)温度和受火时间；(2)受火方式；(3)截面尺寸；(4)混凝土强度、骨料种类；(5)轴压比和荷载偏心距；(6)纵向配筋；(7)混凝土保护层厚度、箍筋、长细比、柱端约束条件等。本文对目前学者提出的钢筋混凝土柱抗火性能的简化理论计算方法进行介绍,并通过计算值与试验值的比较,对这些方法的准确度及可行性进行了评估,并采用以上方法对本文试验试件的抗火性能计算进一步验证了其可行性。结果表明Kodur和Raut的计算方法和Dotreppe等的计算方法分别对钢筋混凝土柱耐火极限、火灾后残余受压承载力的计算偏安全,适用于保守计算钢筋混凝土柱的抗火性能。吴波等的计算方法对耐火极限的计算值和Kodur等的计算方法对火灾后残余受压承载力的计算值与试验值较为接近,但变异系数略偏大,仅适用于粗略计算钢筋混凝土柱的抗火性能。已有地震灾害表明,地震后火灾常有发生,然而目前针对经历地震荷载作用后的钢筋混凝土柱抗火性能的研究未见于国内外已发表文献中,因此本文对钢筋混凝土柱在地震荷载作用后的抗火性能进行了试验研究。通过4根常温钢筋混凝土柱和4根经历地震火灾作用全过程的钢筋混凝土柱的低周循环加载试验,探究了地震火灾后钢筋混凝土柱的抗震性能,并考察了纵向钢筋直径大小、箍筋体积配筋率对地震火灾后钢筋混凝土柱的受剪承载力、延性、滞回耗能能力等的影响。结果表明,地震火灾后钢筋混凝土柱的受剪承载力、刚度及延性均较常温钢筋混凝土柱降低,但能量耗散系数大幅度增加。增加纵向钢筋直径或箍筋体积配筋率均有助于提高地震火灾后钢筋混凝土柱的受剪承载力和刚度；当纵筋直径较小时,增加箍筋体积配筋率可提高地震火灾后钢筋混凝土柱的延性;但增加箍筋体积配筋率将减小钢筋混凝土柱在地震火灾后的能量耗散系数。
[Abstract]:The frequent building fire accidents in recent years have caused enormous economic losses and taken away many precious lives. In order to reduce or even prevent the recurrence of such tragedies, As one of the main load-bearing members of reinforced concrete structures, it is very important to study the fire resistance of reinforced concrete columns. In this paper, the fire resistance of reinforced concrete columns, including the fire resistance limit and the mechanical behavior after fire, is summarized according to the domestic and foreign research results through a large number of literature investigations. Based on the statistical analysis of the test data of 526 specimens, the factors influencing the fire resistance of reinforced concrete columns are determined, which include: 1) the temperature and the time of fire are 2)) the size of section is 3))) the strength of concrete is determined. The concrete cover thickness, stirrups, aspect ratio, column end constraint conditions and so on. In this paper, the simplified theoretical calculation methods for the fire resistance of reinforced concrete columns are introduced, and the accuracy and feasibility of these methods are evaluated by comparing the calculated values with the experimental values. The above method is used to further verify the feasibility of the fire resistance calculation of the specimen tested in this paper. The results show that the calculation methods of Kodur and Raut and Dotreppe and so on are safe to calculate the fire resistance of reinforced concrete columns and the residual compressive capacity after fire, which is suitable for conservatively calculating the fire resistance of reinforced concrete columns. The calculated values of the fire resistance limit of Wu Bo et al and Kodur et al are close to the experimental values, but the coefficient of variation is slightly larger. It is only suitable for rough calculation of fire resistance of reinforced concrete columns. Earthquake disasters have shown that fires often occur after earthquakes. However, the research on fire resistance of reinforced concrete columns after earthquake loads has not been reported in the literature published at home and abroad. Therefore, the fire resistance of reinforced concrete columns subjected to earthquake load is studied experimentally in this paper. Based on the low-cycle cyclic loading tests of four reinforced concrete columns at room temperature and four reinforced concrete columns subjected to the whole process of earthquake fire, the seismic behavior of reinforced concrete columns after earthquake fire was investigated, and the diameter of longitudinal steel bars was investigated. The effect of volume reinforcement ratio of stirrups on shear capacity, ductility and hysteretic energy dissipation capacity of reinforced concrete columns after earthquake fire. The results show that the shear capacity, stiffness and ductility of reinforced concrete columns after earthquake fire are lower than those of normal temperature reinforced concrete columns, but the energy dissipation coefficient increases greatly. Increasing the diameter of longitudinal steel bar or the ratio of volume reinforcement of stirrups will help to improve the shear capacity and stiffness of reinforced concrete columns after earthquake fire, when the diameter of longitudinal reinforcement is small, The ductility of reinforced concrete columns after earthquake fire can be improved by increasing the volume reinforcement ratio of stirrups, but the energy dissipation coefficient of reinforced concrete columns will be reduced by increasing the volume reinforcement ratio of stirrups.
【学位授予单位】：湖南大学
【学位级别】：硕士
【学位授予年份】：2015
【分类号】：TU375.3;TU352.11

【参考文献】