火灾下钢管混凝土柱—钢梁穿筋节点受力性能分析

发布时间：2019-03-12 13:21

【摘要】：节点的抗火研究大部分集中在外加强环节点这类柱贯通式节点层面,而较少涉及到穿筋节点这类梁贯通式节点,因此本论文通过对标准升温曲线作用下钢管混凝土柱-钢梁穿筋节点的耐火性能的数值模拟分析,为该节点抗火提供设计依据。首先,本文在确定恰当的边界条件、单元类型、材料热物理性质以及利用试验验证模型思路正确的基础上,利用ABAQUS有限元软件,对钢管混凝土柱-钢梁穿筋节点在升温过程中的温度场进行数值模拟,并对可能影响温度场的参数进行了分析,为节点耐火分析提供温度荷载施加的依据。得到如下结论：(1)根据温度场分布规律可知,温度分布不均匀,除节点核心区混凝土的温度因为穿筋的作用温度高于非节点区域外,整体节点核心区温度要低于非节点区温度。(2)钢筋的存在可以增强节点在火灾下的升温程度,但是直径的大小对温度场的影响不是很明显。(3)钢梁截面宽度对节点在火灾下的升温情况几乎无影响。(4)防火保护层对于节点在火灾下的升温情况影响显著。防火保护层的存在降低了节点的升温程度,且随着防火保护层厚度的增加而越发明显。其次,本文在利用试验验证模型思路正确的基础上,利用ABAQUS有限元软件,设计了7个常温下承受往复荷载的方钢管混凝土柱-钢梁穿筋节点模型,得到相应极限承载力值的同时并对其进行了参数分析,为节点耐火分析提供静力荷载施加的依据。最后,本文在利用试验验证模型思路正确的基础上,利用ABAQUS有限元软件设计了3个钢管混凝土柱和7个方钢管混凝土柱-钢梁穿筋节点耐火计算模型,得到相应耐火极限的同时并对该类节点的耐火性能进行了分析。得出以下结论：(1)增大荷载比可降低节点的耐火极限和临界温度。降低荷载比可提高节点的耐火极限和临界温度。(2)增大轴压比可降低节点的耐火极限和临界温度。降低轴压比可提高节点的耐火极限和临界温度。(3)钢筋的强度对节点的耐火极限几乎无影响。(4)提高含钢率可提高节点的耐火极限和临界温度。降低含钢率可降低节点的耐火极限和临界温度。(5) 防火层的存在可提高节点的耐火极限和临界温度。
[Abstract]:Most of the research on fire resistance of joint is focused on the layer of column-through-type joint such as the strengthened ring node, but rarely involves the beam-through-type joint such as the piercing joint. In this paper, the fire resistance of the concrete-filled steel tubular column-steel beam piercing joint under the action of the standard heating curve is simulated and analyzed, which provides the design basis for the fire resistance of the joint. Firstly, on the basis of determining the appropriate boundary conditions, element types, material thermophysical properties and using the test to verify the model, the ABAQUS finite element software is used in this paper. The temperature field of the concrete-filled steel tubular (CFST) column-steel beam pierced joint during the heating process is numerically simulated, and the parameters which may affect the temperature field are analyzed, which provides the basis for the fire resistance analysis of the joint. The results are as follows: (1) according to the distribution of temperature field, the temperature distribution is not uniform, except that the temperature of the concrete in the core zone of the joint is higher than that of the non-node region because of the action of the reinforcement. The temperature in the core zone of the whole joint is lower than that in the non-node zone. (2) the existence of steel bars can enhance the warming degree of the joint in the event of fire. However, the influence of the diameter on the temperature field is not obvious. (3) the width of the steel beam has little effect on the temperature rise of the joints under fire. (4) the fire protection layer has a significant effect on the temperature rise of the joints under fire. The existence of the fire protection layer reduces the temperature rise of the joint and becomes more and more obvious with the increase of the thickness of the fire protection layer. Secondly, seven concrete-filled square steel tubular columns and steel beams with reciprocating load under normal temperature are designed by using ABAQUS finite element software, on the basis of the correct thinking of the model, which is verified by the experiment, and the finite element software ABAQUS is used to design seven concrete-filled square steel tubular columns-steel beams. At the same time, the corresponding ultimate load value is obtained and the parameter analysis is carried out, which provides the basis for the static load applied to the fire resistance analysis of the joints. Finally, on the basis of the correctness of the model, three concrete-filled steel tube columns and seven concrete-filled square steel tubular columns-steel beams are designed by using ABAQUS finite element software, and the fire resistance calculation models of concrete-filled steel tubular columns-steel beams are designed in this paper. At the same time, the fire resistance performance of this kind of joints is analyzed. The conclusions are as follows: (1) increasing the load ratio can reduce the fire resistance limit and critical temperature of the joints. Reducing the load ratio can increase the fire resistance limit and critical temperature of the joint. (2) increasing the axial compression ratio can reduce the fire resistance limit and critical temperature of the joint. Reducing the axial compression ratio can increase the fire resistance limit and critical temperature of the joint. (3) the strength of the steel bar has little effect on the fire resistance limit of the joint. (4) increasing the steel content can increase the fire resistance limit and critical temperature of the joint. The fire resistance limit and critical temperature of the joint can be reduced by reducing the steel content. (5) the fire resistance limit and critical temperature of the joint can be increased by the existence of fire-proof layer.
【学位授予单位】：大连理工大学
【学位级别】：硕士
【学位授予年份】：2016
【分类号】：TU398.9

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