圆中空夹层钢管混凝土叠合柱偏压力学性能研究

Mechanical Performance of Circular Concrete-encased CFDST Columns under Eccentric Compression

目的研究圆中空夹层钢管混凝土叠合柱在偏心受压作用下的力学性能,为该类构件的设计和工程应用提供参考。方法采用有限元软件ABAQUS建立精细化非线性分析模型,在模型可靠性得到验证的基础上,对构件进行受力全过程分析。研究叠合柱在不同破坏模态下的工作机理,量化组成部件的内力分配和相互作用关系,考察不同参数对N_(u)-M_(u)曲线的影响。结果增大偏心率,试件的初始刚度和偏压承载力降低,延性提高;名义含钢率由7.1%增至19.8%时,偏压承载力提高了87.5%。结论圆中空夹层钢管混凝土叠合短柱在偏心受压作用下界限破坏的标志为外钢管达到受拉屈服时,受压区边缘的混凝土被压碎;增大钢管屈服强度和名义含钢率可提高试件的偏压承载力。

This paper aims to study the mechanical behavior of the circular concrete-encased concrete-filled double-skin steel tube(CFDST)columns under eccentric compression and provides the reference for the design and engineering application.The mechanical behavior of the circular concrete-encased CFDST stub columns under eccentric compression was numerically investigated in this paper.A finite element model(FEM)was developed and verified using the experimental results.The full-ranged process,the working mechanism and the N_(u)-M_(u) curve were analyzed.An increasing eccentricity will reduce the initial stiffness and the eccentric compression strength,and improve the ductility.When the nominal steel tube ratio increases from 7.1%to 19.8%,the eccentric compression strength will improve 87.5%.The balance failure mode is defined as the simultaneous occurrence of yielding of outer steel tube on the tension side and crushing of the compressive concrete.Increasing the yield strength and nominal steel content of the steel tube can improve the eccentric compression strength.