摘要
为研究受火后T形截面内置格构式圆钢管混凝土短柱的偏压力学性能,以受火时间、偏心率、内部构造为变化参数,设计并完成了11根短柱进行受火后偏心受压加载试验,其中7根T形截面内置格构式圆钢管混凝土短柱和4根普通T形截面RC短柱。通过试验观察了试件的受力破坏过程及形态,分析试件温度-时间曲线、荷载-跨中挠度曲线、侧向挠度-相对高度曲线,分析不同变化参数对试件破坏形态、承载力、刚度退化、耗能能力和延性等力学性能的影响。结果表明:随着受火时间的增加,T形截面内置格构式圆钢管混凝土短柱和普通T形截面RC短柱在不同偏心率下均发生小偏心受压破坏;受火后T形截面内置格构式圆钢管混凝土短柱和普通T形截面RC短柱的承载力、抗弯刚度随着受火时间和偏心率的增加整体呈下降趋势,而延性和耗能能力则呈上升趋势,表现出了更高的承载力、良好的延性;在受火120 min后,承载力下降16.8%,抗弯刚度下降了23.4%,延性增加了85.2%,耗能系数提高12.1%;而普通T形截面RC短柱承载力下降31.74%,抗弯刚度下降64%,延性增加44.83%,耗能能力提高4.6%。总之,内置格构式钢管混凝土T形短柱不仅提高了对混凝土的约束作用,具有足够的安全储备。
To study the eccentric compression mechanical properties of T-shaped built-in latticed concrete-filled circular steel tubular(CFCST)short columns after fire exposure,11 specimens were designed and tested under eccentric compression.The key parameters varied included fire duration,eccentricity,and internal structure.The test specimens comprised seven T-shaped built-in latticed CFCST short columns and four ordinary T-shaped reinforced concrete(RC)short columns.The failure process and morphology of the specimens were observed through experiment.The temperature-time curves,load-midspan deflection curves and lateral deflection-relative height curves of the specimens were analyzed,and the effects of different parameters on failure modes,bearing capacity,stiffness degradation,energy dissipation capacity and ductility were investigated.The results show that with increasing fire duration,both T-shaped built-in latticed CFCST short columns and RC short columns exhibit minor eccentric compression failure under different eccentricity ratios.After fire exposure,the bearing capacity and flexural stiffness of both types of columns generally decrease with increasing fire exposure time and eccentricity,while ductility and energy dissipation capacity generally increase,which exhibit higher bearing capacity and good ductility.After 120 minutes of fire exposure,the bearing capacity of columns decreases by 16.8%,bending stiffness decreases by 23.4%,ductility increases by 85.2%,and the energy dissipation coefficient increases by 12.1%.However,the bearing capacity of ordinary T-shaped RC short columns decreases by 31.74%,bending stiffness decreases by 64%,ductility increases by 44.83%,and energy dissipation capacity increases by 4.6%.It is demonstrated that the T-shaped built-in lattice concrete-filled steel tubular short column enhances the confinement effect on concrete while ensuring an adequate safety margin.
作者
陈海彬
张皓铭
赵寅鹏
吉学超
周中一
CHEN Haibin;ZHANG Haoming;ZHAO Yinpeng;JI Xuechao;ZHOU Zhongyi(College of Civil and Architectural Engineering,North China University of Science and Technology,Tangshan 063020,China;Hebei Key Laboratory of Earthquake Engineering and Disaster Prevention,North China University of Science and Technology,Tangshan 063020,China;Key Laboratory of Earthquake Engineering and Engineering Vibration,Institute of Engineering Mechanics,China Earthquake Administration,Harbin 150080,China)
出处
《建筑结构学报》
CSCD
北大核心
2024年第S2期137-146,共10页
Journal of Building Structures
基金
国家重点研发计划(2022YFF0608904)
国家自然科学基金项目(51478162,51608196)
唐山市科技局应用基础研究项目(23130213E)
唐山市科技计划项目(22150224J)
关键词
内置格构式圆钢管混凝土
短柱
受火试验
静力试验
偏心受压
力学性能
built-in lattice concrete-filled circular steel tube
short column
fire test
static test
eccentric compression
mechanical property
