脱空缺陷对钢管混凝土拉弯构件性能的影响分析  

EFFECTS OF CONCRETE GAP ON THE MECHANICAL PROPERTIES OF CFST MEMBERS SUBJECTED TO BENDING AND TENSION

作　　者：韩浩 廖飞宇 林挺伟 李永进 HAN Hao;LIAO Feiyu;LIN Tingwei;LI Yongjin(College of Transportation and Civil Engineering, Fujian Agriculture and Forestry University, Fuzhou 350002, China;Fujian Yongzheng Construction Quality Inspection Co. Ltd, Fuzhou 350001, China)

机构地区：[1]福建农林大学交通与土木工程学院,福州350002 [2]福建省永正工程质量检测有限公司,福州350001

出　　处：《工业建筑》2018年第3期170-175,90,共7页Industrial Construction

基　　金：国家自然科学基金项目(51578154);福建省财政厅科技专项资助项目(K81150001)

摘　　要：在合理选用材料本构、单元类型、网格划分和边界条件的基础上,采用有限元分析软件建立了考虑脱空缺陷的钢管混凝土拉弯构件有限元分析模型。在验证模型可靠性的基础上,通过对比分析有无脱空缺陷的钢管混凝土拉弯构件的荷载-变形关系曲线、钢管与混凝土拉力分配、界面接触应力等力学性能指标,明晰了脱空缺陷对钢管混凝土拉弯构件受力性能的影响机理。研究结果表明：球冠形脱空缺陷削弱了钢管对混凝土的约束作用,在构件受拉弯荷载时,混凝土受压区开裂严重因而对构件的抗拉承载力贡献较无脱空构件低;外钢管拉力分配比重较高,所受应力较大,且钢管脱空侧由于缺少混凝土支撑作用从而出现局部屈曲,降低了构件抗拉承载力;构件的抗拉承载力系数随脱空率的增大而减小,但减小幅度趋于平缓;相同脱空率下承载力系数随偏心率增大而降低。Based on the rational constitutive relation of materials,element type,meshing and boundary conditions,a finite element model（ FEM） was established for the concrete-filled steel tubular（ CFST） with spherical cap gap subjected to bending and tension. A close agreement was achieved by comparing the load-deformation responses and ultimate strength of FEM and test results. In order to clarify the influence of gap on the mechanical properties of CFST members under bending and tension,a comparative analysis was conducted on the CFST members with or without gap in terms of the load-deformation relationship,tension distribution of tubes and concrete,interface contact stress and so on. The results showed that the spherical cap gap would weaken the confinement effect of steel tube to concrete.When the member were subjected to tension and bending,it would result in more serious cracking at the compression zone of the concrete,and contributed less to the tensile bearing capacity of the member with spherical cap gap than that of the member without gap. The proportion of tensile force of the outer steel pipe was higher and the stress was greater. Meanwhile,local buckling was more likely to occur in the steel tube because of lacking the support of concrete at the location of gap. From the parametric analysis results,it was found that the tensile bearing capacity of the CFST members decreased with the increase of gap ratio. With the same gap ratio,the reduction of ultimate strength caused by gap tended to be more significant when the eccentric ratio increased.

关 键 词：球冠形脱空缺陷 钢管混凝土 拉弯构件 有限元 机理分析 

分 类 号：TU398.9[建筑科学—结构工程]