带拉筋方中空夹层钢管混凝土轴压短柱受力性能研究

Experiment study of stirrup-confined concrete-filled square double-skin steel tubular stub columns under axial loading

通过带拉筋方中空夹层钢管混凝土轴压短柱受力性能试验,研究了拉筋配箍率对试件承载力、刚度、延性及横向变形系数的影响。采用混凝土三轴受力状态本构模型和钢材本构模型,应用ABAQUS有限元分析软件建立并验证了带拉筋方中空夹层钢管混凝土轴压短柱三维实体有限元模型,有限元计算结果与试验结果吻合良好;在此基础上,分析了拉筋对内外方钢管和混凝土约束作用机理。研究结果表明:拉筋能有效缓解了方钢管的局部屈曲,对短柱承载力、刚度、延性的提高效果明显;拉筋加强了内钢管对混凝土的约束作用,使得内钢管受力更加合理,并且拉筋配箍率越大,约束作用越明显。

This paper presents the experimental study of stirrup-confined concrete-filled square double-skin steel tubular stub columns under axial loading. The influences of different stirrup ratios on bearing capacity,stiffness,ductility and strain ratio of stub columns were discussed. ABAQUS was used to establish the 3 D finite element models for these stub columns under axial compression and the effect of different stirrup ratio on the internal force of steel tube and core concrete was further discussed. The FE results agree well with the experimental results. The results indicate that the tensile stirrups in stirrup-confined concrete-filled square double-skin steel tubular stub columns could effectively reduce local bucking of the square steel tube and significantly improve bearing capacity,stiffness and ductility. The stirrups strengthen the confinement effect of the inner steel tube on the concrete,and make the inner steel tube force more reasonable.