摘要
为提供钢筋混凝土梁托柱转换结构的防火设计依据,根据结构的受力特点,设计了两种足尺梁托柱节点单元试件,对两种节点单元试件进行了热力耦合作用下的耐火性能试验;采用有限元分析软件进行数值计算,分析了火灾下钢筋混凝土梁托柱节点单元的热力耦合耐火极限,得出各参数变化对梁托柱节点单元耐火极限变化规律.分析结果表明:升温曲线及最高温度对节点单元的耐火极限影响较大;荷载比为 0.6 的节点单元比荷载比为 0.4 节点单元耐火极限小;节点单元托梁纵向受拉钢筋的保护层厚度不同,其耐火极限从大到小为保护层厚度50 mm、保护层厚度 40 mm、保护层厚度 25 mm;转换托梁中受托柱处附加吊筋的设置可有效提高节点单元的耐火极限,并起到避免发生突然破坏的作用;节点单元托梁四面受火的耐火极限小于三面受火的耐火极限;在相同荷载比及相同受火工况作用下,两种钢筋混凝土梁托柱节点单元的耐火极限和破坏特点不同.
To provide the basis for the fire prevention design of reinforced concrete beam supporting column transfer structures, according to the structural characteristics, two kinds of full size beam supporting column transfer structure joints are designed. The reinforced concrete beam supporting column transfer structure joints are exposed to fire,and their fire resistance is tested. Based on the test results,using ABAQUS -a finite element analysis software, considering the influence of raising temperature curve, loading ratio, protective layer thickness, additional steel bars, the number of surfaces in fire of a transfer girder, the fire resistance of beam supporting column transfer structure joints is analyzed and the variation of the fire resistance for these beam supporting column transfer structure joints is summarized. The analysis results show that heating curve and maximum temperature have a significant influence on fire resistance;the fire resistance limit of joint units with load ratio of 0.6 is smaller than that of joint units with load ratio of 0.4;the thickness of the protective layer of the longitudinal tensile reinforcement of the joint unit differs, while the fire resistance limit ranges from large to small for protective layer thickness of 50 mm,40 mm,and 25 mm,respectively;hanging steel bars in the transfer girder can improve the fire resistance and help avoid sudden damage. The more surfaces of the transfer girder are in fire, the shorter is the fire resistance. Under the same loading ratio, two kinds of beam supporting column transfer structure joints have different damage characteristics and fire resistance.
作者
孔维一
傅传国
刘伟庆
KONG Weiyi;FU Chuanguo;LIU Weiqing(College of Civil Engineering,Southeast University,Nanjing 210096,China;College of Civil Engineering,ShandongJianzhu University,Jinan 250101,China;College of Civil Engineering,Nanjing Tech University,Nanjing 211816,China)
出处
《西南交通大学学报》
EI
CSCD
北大核心
2019年第3期548-555,共8页
Journal of Southwest Jiaotong University
基金
国家自然科学基金资助项目(51278289,51478254)
关键词
钢筋混凝土
转换结构
梁托柱节点单元
热力耦合
耐火极限
reinforced concrete
transfer structure
beam supporting column transfer structure joints
high temperature
fire resistance
