带约束拉杆十字形钢管混凝土短柱轴压试验研究  

Experimental Study on the Cross-Shaped CFST Stub Column with Binding Bars Subjected to Axial Compression

作　　者：赵小芹 左志亮[2] 蔡健[2,3] ZHAO Xiaoqin;ZUO Zhiliang;CAI Jian(School of Civil Engineering,Guangzhou City University of Technology,Guangzhou 510800,China;School of Civil Engineering&Transportation,South China University of Technology,Guangzhou 510641,China;State Key Laboratory of Subtropical Building Science,South China University of Technology,Guangzhou 510641,China)

机构地区：[1]广州城市理工学院土木工程学院,广州510800 [2]华南理工大学土木与交通学院,广州510641 [3]华南理工大学亚热带建筑科学国家重点实验室,广州510641

出　　处：《建筑钢结构进展》2022年第7期38-48,共11页Progress in Steel Building Structures

基　　金：国家自然科学基金(51408230);广东省自然科学基金(2022A1515011115);广东省普通高校青年创新人才项目(2018KQNCX370);中央高校基本科研业务费专项资金资助项目(2019MS124)。

摘　　要：进行了11个带约束拉杆和5个不带约束拉杆十字形钢管混凝土短柱试件的轴压试验研究,讨论在不同约束拉杆间距与直径、钢板厚度与屈服强度以及截面尺寸下十字形钢管混凝土短柱的破坏特点、承载力、延性、拉杆与钢管的应变发展特点等轴压性能。结果表明,约束拉杆的设置改变了钢管的屈曲模态,延缓了钢管局部屈曲的发生,限制了阴角处钢管的外鼓变形,使钢板的纵、横向应变分布更为均匀,保证了钢管纵向承载力的发挥,提高了核心混凝土的约束效应,有助于提高十字形钢管混凝土轴压短柱的承载力和延性;减小拉杆间距、增大板厚、增大拉杆直径时,拉杆约束钢管外鼓变形的作用增大。采用现行规程中的矩(方)形钢管混凝土柱轴压承载力计算公式对试件峰值荷载进行估算,结果表明只有当钢板相对宽厚比小于22时,不带拉杆试件的承载力才能按叠加材料强度的EC4公式估算;带拉杆试件的承载力至少可按材料强度叠加法估算,拉杆间距较小或钢板厚度较大时可近似用GJB 4142—2000和DBJ 13-51—2003公式估算。最后,考虑钢管和拉杆的约束效应以及不带拉杆钢管纵向承载力低的情况,提出了十字形钢管混凝土柱轴压承载力计算公式,计算值与试验值吻合良好。A set of tests are conducted for evaluating the behaviors of cross-shaped concrete-filled steel tubular stub columns subjected to axial compression,including eleven specimens with binding bars and five specimens without binding bars. The parameters are the spacing and diameter of binding bars,the thickness and strength of steel plates,and section size. The axial compression behaviors of the specimens are discussed,such as the characteristics of failure,the bearing capacity and ductility,and the development characteristics of the strain of binding bars and steel tube. The results indicate that by setting binding bars the buckling modes of the steel plates are changed,the appearance of local buckling is postponed,the outward deformation around the concave corners of tube is restrained,and the strain distribution of steel tube is more uniformly.Then the longitudinal bearing capacity of the tube can be guaranteed,the confinement effects of steel tube on the core concrete are increased,and the bearing capacity and ductility are enhanced. The confinement effects of binding bars to the outward deformation of steel tube are increased with the decrease of distance of bars,as well as the increase of thickness of plates or the increase of diameter of bars. The methods in current standards for calculating the ultimate strength of rectangle or square CFST stub columns are used to evaluate the maximum strengths of the specimens. The results indicate that only when the width-thickness ratio is less than 22,the maximum strengths of specimens without bars can be evaluated by the Code EC4 in which the strength superposition method is adopted. When the distance of bars is small or the thickness of steel tube is large,the Codes GJB 4142—2000 and DBJ 13-51—2003 can be used to evaluate the maximum strengths of specimens with bars,otherwise the strength superposition method is also appropriate. Finally,considering the confinement effects of steel tube and binding bars,and the loss of longitudinal capacity of steel tube in the speci

关 键 词：十字形钢管混凝土短柱 约束拉杆 轴压试验 极限承载力 

分 类 号：TU398.9[建筑科学—结构工程]