不同抗震设防烈度区同类既有底框结构的抗火性能研究

发布时间：2018-07-17 04:52

【摘要】：上世纪八、九十年代,我国建造了大量的钢筋混凝土底部框架上部砌体建筑。底框建筑底层大空间多用作商业,火灾荷载大,一旦着火,危害严重;另外,这类结构竖向刚度不均匀,上刚下柔,抗震性能差,火灾下结构的安全性怎样,值得深入研究。2003年湖南衡阳大火和2015年哈尔滨南勋市场“1.2”大火,火灾后房屋局部倒塌,不仅造成了财产的损失,而且付出了生命的代价。上述倒塌的房屋为底框结构,建于上世纪八、九十年代,且抗震设防烈度为六度。如果该房屋位于抗震设防烈度七度区或八度区,情况会怎样?上述命题的提出,就是本课题试图要研究的问题。本文通过研究基于ABAQUS软件的火灾下钢筋混凝土结构的精细化建模技术,对不同抗震设防烈度区同类既有底框结构的抗火性能进行分析,旨在研究不同抗震设防烈度区底框结构的地震抗力对应的抗火能力,可为实际工程安全评估提供参考,也可为消防救援提供参考依据。主要研究内容如下:1)基于ABAQUS有限元软件对火灾下钢筋混凝土结构的精细化建模技术中的相关参数进行研究,应用上述研究成果对文献中已有的试验进行建模计算和数据对比,从而验证了研究成果的正确性。2)按照89系列规范对不同抗震设防烈度区的某底商住宅楼进行结构设计,选取各烈度区模型中的一榀特定底部框架结构作为研究对象,并对特定结构中各构件的截面和配筋进行了对比。3)选取七度区的特定底部框架结构,分别对底部一层受火和底部二层受火工况下特定底部框架结构上部砌体的荷载传递、托梁上的荷载分布及底部框架的力学性能进行研究,探讨受火前与受火后底框结构的受力特性。4)对不同抗震设防烈度区底部二层受火工况下特定底部框架结构的耐火极限和破坏机制进行了对比分析,研究其抗火性能,表明各烈度区框架柱的耐火极限达不到《建筑设计防火规范(GBJ16-87)》的要求。
[Abstract]:In 1980s and 1990s, a large number of reinforced concrete bottom frame upper masonry buildings were built in China. The large space of the bottom floor of the bottom frame building is mostly used for commercial purposes, and the fire load is large, once the fire is on fire, the damage is serious. In addition, the vertical stiffness of this kind of structure is uneven, the upper stiffness is not uniform, the upper frame is flexible, the seismic performance is poor, and how is the structure safe under fire? The fire in Hengyang, Hunan Province in 2003 and the "1.2" fire in 2015 in Haerbin Nanxun Market, which caused the partial collapse of houses after the fire, not only caused the loss of property, but also paid the price of life. The collapsed building is a base frame structure, built in the 1980s and 1990s, and the seismic fortification intensity is 6 degrees. What happens if the building is located in the seismic fortification area of seven or eight degrees? The proposition mentioned above is the problem that this subject tries to study. In this paper, the fine modeling technology of reinforced concrete structures under fire based on Abaqus software is studied, and the fire resistance of similar existing bottom frame structures in different seismic fortification intensity regions is analyzed. The aim of this paper is to study the fire resistance of the base frame structure in different seismic fortification intensity areas, which can provide reference for engineering safety assessment and fire rescue. The main research contents are as follows: (1) based on Abaqus finite element software, the relevant parameters in the fine modeling technology of reinforced concrete structures under fire are studied. The above research results are used to model and calculate the existing experiments in the literature and to compare the data. Therefore, the correctness of the research results is verified. 2) according to the 89 series code, the structural design of a commercial residential building in different seismic fortification intensity zones is carried out, and a specific bottom frame structure in each intensity zone model is selected as the research object. At the same time, the section and reinforcement of each member in the specific structure are compared. 3) the specific bottom frame structure in the seven degree region is selected, and the load transfer of the upper masonry of the specific bottom frame structure under the condition of fire at the bottom layer and under the condition of the fire at the bottom and the second floor at the bottom, respectively, is carried out. The load distribution on the bracket and the mechanical properties of the bottom frame are studied. This paper probes into the stress characteristics of the base frame structure before and after fire (.4) compares and analyzes the fire resistance limit and failure mechanism of the specific bottom frame structure under different seismic fortification intensity zones under the condition of the fire at the bottom two stories, and studies the fire resistance performance of the frame structure. It is shown that the fire resistance limit of frame columns in different intensity zones is not up to the requirements of the Code for Building Design Fire Resistance (GBJ16-87).
【学位授予单位】：中国建筑科学研究院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU352.5

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