钢管混凝土柱-外环板式组合梁节点在地震损伤后的耐火性能数值分析  

Numerical Analysis on the Fire Resistance of the Concrete-Filled Steel Tubular Column to Composite Beam with Outer Ring Plate Connection After Earthquake Damage

作　　者：陈润亭 王文达[1] 魏国强[1] 郑龙 CHEN Runting;WANG Wenda;WEI Guoqiang;ZHENG Long(Key Laboratory of Disaster Prevention and Mitigation in Civil Engineering of Gansu Province,Lanzhou University of Technology,Lanzhou 730050,China)

机构地区：[1]兰州理工大学甘肃省土木工程防灾减灾重点实验室,兰州730050

出　　处：《建筑钢结构进展》2021年第8期11-21,31,共12页Progress in Steel Building Structures

基　　金：国家自然科学基金(51778274);甘肃省高校协同创新团队项目(2018C-08)。

摘　　要：为研究钢管混凝土柱-外环板式组合梁节点在地震损伤后的耐火性能,通过验证已有试验,在模型可靠的基础上,建立了地震损伤后组合梁节点在楼板以下区域受火工况下耐火极限有限元计算模型。分析了2个组合梁节点在滞回加载中的塑性累积损伤和楼板以下区域受火工况对节点耐火极限、破坏模态的影响。结果表明:组合梁节点随着滞回加载位移的不断增大,混凝土柱与楼板的受拉塑性损伤及受压塑性损伤程度不断加重。随着受火时间的延长,柱混凝土纵剖面的温度场分布由Y形变为X形,栓钉沿纵向有明显的温度梯度,混凝土楼板由于栓钉的影响,温度场分布呈现波浪形。在柱端火灾荷载比为0.4、梁端火灾荷载比为0.4、节点CFSTJ-1在无损伤情况下达到耐火极限时,节点破坏为组合梁压弯破坏,而在有损伤情况(D=0.688)下,节点下柱出现了较为严重的鼓曲破坏;节点CFST-2在无损伤情况下达到耐火极限时,组合梁发生压弯破坏并伴随柱的轻微弯曲,而在有损伤情况(D=0.638)下,柱发生严重的弯曲破坏。节点随着损伤程度的加大,耐火极限显著降低。In order to study the fire resistance of the concrete-filled steel tubular column to composite beam with outer ring plate connection after earthquake damage,a finite element model is verified with corresponding tests.The finite element model for fire resistance of composite beam joint under fire in the area below RC slab after the earthquake is built.The effects of plastic cumulative damage and fire condition on the fire resistance,failure modes of two joints under hysteretic loading are analyzed.The results indicate that with the increase of the hysteretic displacement of composite beam joints,the degree of tensile and compressive plastic damage of concrete column and RC slab is getting worse.As the fire lasts longer,the temperature field distribution of the longitudinal section of the concrete column changes from Y-shape to X-shape,and the stud has a distinct temperature gradient along the longitudinal direction.The temperature field distribution of the RC slab is wavy due to the influence of the stud.In the case of the column fire load ratio and the beam fire load ratio is 0.4,when CFSTJ-1 reaches the fire resistance without damage,the composite beam has a bending failure.However,when the damage index is 0.688,the lower column of CFSTJ-1 presents relatively severe bulging failure.When CFSTJ-2 reaches the fire resistance without damage,the composite beam has a bending failure with slight bending of the column.However,when the damage index is 0.638,the column occurs severe bending failure.With the increase of the damage degree,the fire resistance of the joints decreases significantly.

关 键 词：钢管混凝土柱 外环板式节点 耐火极限 破坏模态 损伤指数 

分 类 号：TU352.5[建筑科学—结构工程] TU398