摘要
对3层钢框架结构边跨梁在火灾作用下的性能进行足尺试验研究,试验中测量了炉温、钢梁和混凝土板沿截面高度的温度场分布以及钢梁和混凝土板的竖向位移。结果表明:钢梁下翼缘、腹板和烟气的温度基本一致;混凝土板内的温度滞后于钢梁温度,且在钢梁降温阶段,混凝土板温度持续升高,因此混凝土板限制了钢梁升温阶段的膨胀和降温阶段的收缩;钢梁在122 min的升温过程中变形较小,且在升温阶段变形就开始恢复,最终出现向上的竖向位移,这是框架结构中钢梁火灾行为区别于单个构件火灾行为的特点之一,表明框架结构中与混凝土楼板形成整体的边跨梁具有较强的抗火性能;最后钢梁上下翼缘焊缝被拉裂破坏,因此在工程应用中应尽量避免工地现场施焊的全焊接节点。利用非线性有限元软件对试验梁进行了火灾反应分析,得出了试验梁的温度场分布和位移反应的变化规律。有限元分析结果和试验结果基本一致,验证了有限元分析模型的正确性和可行性。
This paper studies the performance in fire of the edge beam in a full-scale three-story steel framed building.The temperature distribution across the steel beam and reinforced concrete slab sections was measured.The displacements at different sections of steel beam and reinforced concrete slab were recorded during the experiment.It was found that the temperature at the bottom flange and web of steel beam was almost the same as that of the smoke in the furnace.But the temperature at the top flange of beam was different.The temperature rise of concrete was slower than that of the steel,resulting in a different restraint condition on steel beams provided by the concrete slab.The vertically downward deformation of beams was small during the 122 minutes of fire,which began to recover even at the stage of temperature rising and became vertically upward deformation in the end of fire.This indicates that performance of steel beam in full-scale steel framed buildings in fire is well.Cracks of welding at top and bottom flanges of steel beams were developed.The engineering suggestion is given that the whole penetration field weld of joints should be avoided.In addition,an analytical investigation was carried out by employing the finite element analysis package.Temperature distribution and variation of the structural members were obtained from the finite element method（FEM） during the test.By comparing the results of the finite element analysis with experimental measurement,a good agreement is found,showing the accuracy and feasibility of the analysis with FEM.
出处
《建筑结构学报》
EI
CAS
CSCD
北大核心
2011年第9期92-98,共7页
Journal of Building Structures
基金
国家重点基础研究发展规划项目(2001CB409603)
国家自然科学基金项目(50878069)
关键词
钢框架结构
边跨梁
足尺模型
抗火试验
有限元分析
抗火性能
steel framed structure
edge beam
full-scall building model
fire test
finite element analysis
performance in fire
作者简介
作者简介：吕俊利（1978-），男，山东安丘人，博士研究生，讲师。E—mall：ljll978@163．com
