基于升降温全过程分析的SRC柱耐火性能指标研究

发布时间：2018-01-08 21:03

本文关键词：基于升降温全过程分析的SRC柱耐火性能指标研究　出处：《苏州科技大学》2017年硕士论文　论文类型：学位论文

【摘要】：型钢混凝土柱(以下简称SRC柱)具有承载力高,刚度大,抗震、抗火、耐腐蚀性能好和技术经济效益好等优点,在多层、高层、超高层建筑以及工业厂房中得到广泛的应用。对SRC柱在高温下的性能研究多集中在标准升温条件下的耐火极限和火灾后剩余承载力的研究。但在实际火灾作用下,SRC柱会经历升温和降温两个阶段,由于混凝土的热惰性,截面升温存在滞后性,在降温阶段,外部混凝土开始降温,但内部型钢和部分混凝土仍处于升温状态,柱承载力继续下降,故存在降温段发生延迟破坏的可能性。为了解SRC柱在降温段破坏的可能性,更准确地评估SRC柱在实际火灾下的耐火能力,本文基于SRC柱的抗火全过程分析,对其抗火性能指标DHP进行研究。主要工作如下:(1)利用有限元软件ABAQUS建立了SRC柱三维温度场计算模型和全过程力学计算模型,并利用已有试验数据对其有效性与合理性进行了验证。(2)定义场变量,编制可以自动识别和转换材料本构关系的子程序USDFLD,实现了对SRC柱升、降温全过程的耐火性能计算。(3)验证了SRC柱在降温段发生破坏的可能。通过探究SRC柱在全过程火灾作用下承载力的变化,对比耐火极限,定义了衡量SRC柱在全过程火灾作用下的耐火性能指标DHP,即可使SRC柱在降温段发生破坏的最小升温时间(Duration of the Heating Phase)。(4)对影响SRC柱耐火极限及全过程火灾作用下的耐火性能指标(DHP)的主要参数进行计算分析,包括火灾荷载比、SRC柱截面尺寸、长细比、偏心率、型钢截面尺寸、混凝土强度。对比分析可知,荷载比、柱截面尺寸、长细比对SRC柱在升降温全程火灾作用下的耐火性能影响较大。(5)在以上模型计算的基础上,通过回归分析建立了SRC柱耐火极限R和全过程火灾下耐火性能指标DHP的简化计算公式,并建立了DHP关于R的函数关系式。
[Abstract]:SRC columns (hereinafter referred to as SRC columns) have the advantages of high bearing capacity, large stiffness, earthquake resistance, fire resistance, good corrosion resistance and good technical and economic benefits. The research on the performance of SRC columns at high temperature is mainly focused on the fire resistance limit and the residual bearing capacity after fire under the standard temperature rise condition. Use it. SRC columns will go through two stages of heating and cooling. Due to the thermal inertia of concrete, the section of the temperature rise has hysteresis, in the cooling stage, the external concrete began to cool down. However, the internal steel and some concrete are still in the state of heating up, and the bearing capacity of the columns continues to decrease, so there is the possibility of delayed failure in the cooling section. In order to understand the possibility of failure of the SRC column in the cooling section. In order to evaluate the fire resistance of SRC columns more accurately, this paper based on the analysis of the whole process of fire resistance of SRC columns. The main work is as follows: (1) the three-dimensional temperature field calculation model and the whole process mechanical calculation model of the SRC column are established by using the finite element software ABAQUS. The validity and reasonableness of the field variables are verified by the existing experimental data. The field variables are defined and a subprogram, USDFLD, which can automatically identify and transform the constitutive relations of materials is developed. The fire resistance calculation of the whole process of rising and cooling of SRC column is realized. The possibility of failure of SRC column in the cooling section is verified. The change of bearing capacity of SRC column under the action of fire during the whole process is explored by means of exploring the change of bearing capacity of SRC column in the whole process of fire. Compared with the fire resistance limit, the fire resistance index (DHP) of the SRC column is defined to measure the fire resistance of the column under the action of the whole process fire. The minimum heating time for the failure of the SRC column in the cooling stage is #number0#). The main parameters which affect the fire resistance limit of SRC column and the fire resistance index of SRC column under the action of fire during the whole process are calculated and analyzed. Including the fire load ratio SRC column section size, slenderness ratio, eccentricity, steel section size, concrete strength. The aspect ratio of SRC column has a great influence on the fire resistance of SRC column under the action of rising and cooling the whole fire. 5) on the basis of the above model calculation. By regression analysis, a simplified formula for calculating the fire resistance limit R of SRC column and the fire resistance index DHP under the whole process of fire is established, and the function relation of DHP about R is established.
【学位授予单位】：苏州科技大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU398.9;TU352.5

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