四周受火异形截面部分包覆钢-混凝土轴压组合柱耐火性能试验研究  

Experimental study on fire resistance of axial-loaded special-shaped partially encased steel-concrete composite column subjected to fire on all sides

作　　者：杨欢 刘用 王静峰[1,3] 徐秋雨 YANG Huan;LIU Yong;WANG Jingfeng;XU Qiuyu(School of Civil Engineering,Hefei University of Technology,Hefei 230009,China;Anhui Advanced Steel Structure Technology and Industrialization Collaborative Innovation Center,Hefei University ofTechnology,Hefei 230009,China;Anhui Provincial Key Laboratory of Civil Engineering Structures andMaterials,Hefei University of Technology,Hefei 230009,China)

机构地区：[1]合肥工业大学土木与水利工程学院,安徽合肥230009 [2]合肥工业大学先进钢结构技术与产业化协同创新中心,安徽合肥230009 [3]合肥工业大学土木工程结构与材料安徽省重点实验室,安徽合肥230009

出　　处：《建筑结构学报》2024年第2期52-62,共11页Journal of Building Structures

基　　金：国家自然科学基金项目(52108130);安徽省自然科学基金项目(2108085QE248);中央高校基本科研业务费专项资金(JZ2021HGTA0158,PA2021GDSK0078)。

摘　　要：异形截面部分包覆钢-混凝土组合(PEC)柱是解决高层钢结构住宅凸柱问题的有效方法之一,因其型钢翼缘外露,故而抗火问题备受关注。为研究异形截面PEC柱的抗火性能,以截面形式和轴压比为参数设计并制作了4根异形截面PEC柱,开展了恒载升温试验,得到火灾下异形截面PEC柱的破坏模式、竖向与侧向变形-时间关系曲线和耐火极限,并分析其温度场分布与变形规律。研究结果表明:随着火灾下截面损伤增加,L形及T形截面PEC柱逐渐由轴压受力状态分别转为双向及单向偏压受力状态,十字形截面PEC柱仍保持轴压受力状态;在上端球铰和下端单向铰边界条件下,L形截面PEC柱发生双向弯曲失稳,T形截面PEC柱发生平面外弯曲失稳,十字形截面PEC柱发生平面内弯曲失稳;在轴压比为0.4、没有防火保护条件下,L形截面PEC柱耐火极限为41 min,T形截面和十字形截面PEC柱耐火极限分别为32.5 min和29 min;当轴压比由0.4增加至0.55时,十字形截面PEC柱耐火极限降低了28.7%。借鉴EN 1994-1-2中建议的四周受火规则截面PEC柱高温承载力简化计算方法,对异形截面PEC柱高温承载力进行计算,计算结果偏保守。Special-shaped partially encased composite steel and concrete(PEC)columns is one of the effective solutions to solve the convex column problem of high-rise steel residential buildings.Due to the exposed steel flanges,its fire resistance has attracted much attention.In order to explore the fire resistance of special-shaped PEC columns,four special-shaped PEC columns were designed and fabricated with different cross-section shapes and axial compression ratios,and the fire tests with constant axial load were carried out.The failure mode,vertical and lateral deformation-time curves and fire resistance of special-shaped PEC columns under fire were obtained,and the temperature field distribution and deformation modes were analyzed.The results show that with the damage evolution under fire,L-shaped and T-shaped PEC columns gradually change from axial compression to bidirectional and unidirectional eccentric compression,respectively,while the cross-shaped PEC columns still maintain axial compression.Under the boundary conditions of the upper spherical hinge and the lower unidirectional hinge,the L-shaped PEC column fails in the bidirectional flexural buckling,the T-shaped PEC column fails in the out-of-plane flexural buckling,and the cross-shaped PEC column fails in the in-plane flexural buckling.Under the axial compression ratio of 0.4,the fire resistance of L-shaped PEC column without fire protection reaches 41 min,the fire resistances of T-shaped and cross-shaped PEC columns are 32.5 min and 29 min,respectively.When the axial compression ratio increases from 0.4 to 0.55,the fire resistance of the cross-shaped PEC column decreases by 28.7%.It is found that the simplified bearing capacity calculation method of regular cross-section PEC columns subjected to fire on all sides recommended in EN 1994-1-2 is conservative to predict the bearing capacity of special-shaped PEC columns at fire resistance.

关 键 词：部分包覆钢-混凝土组合柱 异形截面 火灾试验 耐火性能 高温承载力 

分 类 号：TU398.9[建筑科学—结构工程]