摘要
在组合十字形钢管混凝土柱的基础上,提出了一种在其横向和纵向增加槽钢数量以改变柱肢长度的多重组合式十字形钢管混凝土柱。进行了4根多重组合式十字形钢管混凝土柱轴压试验,试件设计的变化参数为构件长度和截面形式。试验结果表明:试件长度为500mm的破坏形态属于轴压破坏,试件长度为700mm和900mm的破坏形态类似于偏压破坏;增加柱肢长度有效地提高了试件的极限承载力并改善了其延性。在此基础上,采用有限元软件ABAQUS对4根多重组合式十字形钢管混凝土异形柱轴压的荷载-变形受力全过程进行模拟分析,模拟的荷载-位移曲线结果表明:试件的初始刚度及其极限承载力与试验结果吻合较好,但在弹塑性阶段,两者相差较大,这是因为有限元模拟时所采用的混凝土本构关系没有很好地反映该结构中外钢管对内部混凝土的多重约束作用。研究分析了构件在受力过程中各组成部分荷载分配的工作机理,分析结果表明:多重组合式十字形柱中钢管承担了接近70%的荷载;对比截面形式相同的空钢管,多重组合式十字形柱中混凝土的存在提高了钢材的延性;由于钢材对芯柱内填混凝土的多重约束,混凝土达到峰值荷载后承担的荷载在短暂下降后会继续提高。
A new type of composite concrete-filled steel tube column with multiple sections is proposed.The axial compression tests of four multi-composite concrete filled steel tube columns are carried out by changing the specimen length and cross-section patterns.The test results show that the failure mode of the specimen with a length of 500 mm belongs to axial compression failure,while the failure mode of the specimen with a length of 700 mm and 900 mm is similar to the bias failure.The ultimate bearing capacity and ductility of the specimens are improved by increasing the length of the column legs.On this basis,the finite element software ABAQUS is used to simulate the whole load-deformation process of four multi-composite cross-shaped concrete-filled steel tubular columns under axial compression.The initial stiffness and ultimate bearing capacity with the test results are in good agreement,but they have large difference in the elastic-plastic stage.The reason mainly lies in that the finite element simulations of the constitutive relationship of concrete can not properly reflect the multiple constraints of structural forms in the steel tube of concrete.The working mechanism of load distribution of components in the process of stress is studied and analyzed.Compared with the hollow steel tube with the same cross section,the existence of concrete in the multi-composite cross column improves the ductility of the steel.Due to the multiple constraints of steel on the concrete filled in the core column,the load borne by the concrete after reaching the peak load will continue to rise after a short drop.
作者
黄宏
王文鹏
杨超
方旭
HUANG Hong;WANG Wenpeng;YANG Chao;FANG Xu(College of Engineering and Architecture,East China Jiaotong University,Nanchang 330013,Jiangxi,China)
出处
《实验力学》
CSCD
北大核心
2020年第6期1092-1100,共9页
Journal of Experimental Mechanics
基金
国家自然科学基金(51868020)
江西省自然科学基金重点项目(20192ACBL21002)
江西省青年科学基金项目(20171BAB216044)
江西省教育厅科学技术研究项目(GJJ170397)资助。
关键词
多重组合式
轴压承载力
有限元分析
multiple combination
axial bearing capacity
finite element analysis
