火灾下钢筋混凝土梁托柱转换结构B型节点耐火性能试验研究

发布时间：2018-01-04 05:20

本文关键词：火灾下钢筋混凝土梁托柱转换结构B型节点耐火性能试验研究　出处：《山东建筑大学》2017年硕士论文　论文类型：学位论文

【摘要】：随着多功能建筑的发展,转换层的使用越来越广泛,众多学者对转换层的结构形式和受力特性展开了广泛的研究工作,取得了丰硕的研究成果,但对转换结构的抗火性能研究还少见报道。转换结构在建筑结构中起着承上启下的传力关键作用,在火灾中其承载性能的劣化会对结构的安全产生严重的影响。因此,开展转换结构抗火性能研究具有重要的理论和现实意义。梁托柱转换结构是转换层中常见的转换结构形式之一,本文主要针对钢筋混凝土梁托柱转换结构中的B型节点的抗火性能进行试验研究。考虑了荷载比、受火工况等因素变化的影响,通过对B型节点在荷载和标准升温耦合作用下的耐火性能全过程试验,观察了试验现象,分析总结了节点试件的温度场分布规律、变形特点、破坏形态和耐火极限,分析总结了荷载比、受火工况等因素对节点试件耐火性能的影响规律。采用ABAQUS大型有限元软件对节点试件在热力耦合作用下的性能进行了模拟计算和对比分析。试验结果显示,在高温和荷载耦合作用下,对试件施加的荷载比越大,耐火时间相对越短,即耐火极限越小;在荷载比相同的条件下,试件四面受火的耐火极限小于三面受火,四面受火下的挠度变形比三面受火时大,梁托柱转换结构B型节点受火面的增加会降低试件的耐火性能;在对达到耐火极限自然降温后的节点试件观察发现,挠曲变形关于受托柱不对称,最大挠度出现在受托柱顶偏心加载一侧(受托柱受压一侧),托梁的开裂主要是底部受拉区的受弯垂直裂缝,竖直裂缝在接近托梁截面高度中央时开始向受托柱方向斜向延伸,试件的破坏都是由于几个受弯主裂缝发展引起的。
[Abstract]:With the development of multi-function building, the transfer layer is more and more widely used. Many scholars have carried out extensive research work on the structural form and mechanical characteristics of the transfer story, and have achieved fruitful research results. However, the research on the fire resistance of the transfer structure is rarely reported. The transfer structure plays a key role in the transfer of power between the upper and the lower parts of the building structure. In the fire, the deterioration of its bearing capacity will have a serious impact on the safety of the structure. It is of great theoretical and practical significance to study the fire resistance of the transfer structure. The beam-beam-column transfer structure is one of the most common transfer structures in the transfer layer. In this paper, the fire resistance of type B joints in reinforced concrete beam-column transfer structures is studied, and the load ratio and fire condition are considered. Through the whole process test of the fire resistance of type B joints under the coupling of load and standard temperature rise, the experimental phenomena were observed, and the distribution law of temperature field and deformation characteristics of the specimens were analyzed and summarized. The failure pattern and fire resistance limit are analyzed and summarized. The effect of fire condition on the fire resistance of joint specimens was studied. The performance of joint specimens was simulated and analyzed by ABAQUS finite element software under thermal coupling. The test results were compared with each other. Show. Under the coupling action of high temperature and load, the larger the load ratio is, the shorter the fire resistance time is, that is, the smaller the fire resistance limit is. Under the same load ratio, the fire resistance limit of the specimen under fire on four sides is smaller than that on three sides, and the deflection deformation under fire on four sides is larger than that on three sides. The fire resistance of the specimens will be reduced with the increase of the fire surface of the B-type joints of the beam-beam-column transfer structure. It is found that the flexural deformation is asymmetric with respect to the supporting column, and the maximum deflection appears on the eccentric loading side of the top of the supporting column (the side of the supporting column under pressure). The crack of the bracket is mainly the flexural vertical crack of the bottom tensile zone, and the vertical crack begins to extend diagonally to the supporting column when it is near the center of the section height of the bracket. The failure of the specimen is caused by the development of several bending cracks.
【学位授予单位】：山东建筑大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU375.1;TU352.5

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