摘要
近年来,椭圆钢管混凝土结构日益受到建筑师与结构工程人员的青睐,与传统的圆形和方形钢管混凝土柱相比,椭圆钢管混凝土柱具有流线型外观和较高的抗扭刚度,在高层和大跨等建筑结构中具有较广泛的应用前景。研究者已对圆形和方形钢管混凝土的火灾后界面黏结性能展开试验与理论研究,但尚缺少对椭圆钢管混凝土火灾后界面黏结性能的相关研究。文章采用弹簧单元模拟钢管-混凝土界面的滑移,建立可分析椭圆钢管混凝土火灾后界面性能的有限元模型,并与具有相同界面接触面积的圆形和方形钢管混凝土进行比较,深入分析椭圆、圆形和方形钢管混凝土的温度分布、火灾后界面黏结应力-滑移关系和火灾后黏结强度。最后,在建立的有限元模型基础上,对影响椭圆钢管混凝土火灾后黏结强度的重要参数进行分析,研究参数包括:目标温度(20℃、600℃和800℃)、恒高温时间(30min、90min、120min和180min)、混凝土强度(30MPa、40MPa、50MPa和60MPa)、截面周长(388mm、484mm、630mm和727mm)和纵横比(1.25、1.50、2.00和2.25),研究发现:混凝土强度和截面周长对椭圆钢管混凝土的火灾后界面黏结强度影响明显,而其他参数影响相对较小。
In recent years, the elliptical concrete-filled steel tube(CFST) structure has attracted the attentions of architects and structural engineers gradually.Compared with the traditional circular and square CFST columns, the elliptical CFST columns have streamline appearance and can provide higher torsion rigidity, so they have wide application prospect in high-rise and large-span building structures.Previous researchers have investigated the post-fire bond behaviour of circular and square CFSTs experimentally and theoretically, but no relevant research has been reported on the post-fire bond behaviour of elliptical CFST.Spring elements are used to simulate the slip between the steel tube and concrete, and finite element analysis(FEA) model is developed to analyse the post-fire bond behaviour of elliptical CFSTs.For comparison, the FEA models of circular and square CFSTs with the same interface contact area as that of the elliptical CFST are established as well.The temperature distribution, post-fire bond stress-slip relationship and bond strength of the three types of CFSTs are analysed according to the FEA models.Finally, based on the established FEA model, parametric study on the post-fire bond strength of elliptical CFSTs is conducted.The investigated parameters include: target temperature(20 ℃, 600 ℃ and 800 ℃), high temperature duration time(30 min, 90 min, 120 min and 180 min), concrete strength(30 MPa, 40 MPa, 50 MPa, 60 MPa), section perimeter(388 mm, 484 mm, 630 mm, 727 mm) and aspect ratio(1.25, 1.50, 2.00, 2.25).It can be found that the influences of concrete strength and section perimeter on the bond strength of elliptical CFST after fire are significant, while the influence of other parameters is relatively minor.
作者
宋天诣
刘夏璐
项凯
Song Tianyi;Liu Xialu;Xiang Kai(Beijing University of Technology,Beijing 100124,China;Tianjin Fire Research Institute of MEM,Tianjin 300381,China)
出处
《土木工程学报》
EI
CSCD
北大核心
2021年第6期41-52,共12页
China Civil Engineering Journal
基金
国家自然科学基金(51778018)
国家重点研发计划(2018YFC0807600)。
关键词
椭圆钢管混凝土
火灾后
黏结性能
黏结强度
elliptical concrete-filled steel tube
post-fire
bond behaviour
bond strength
