钢管混凝土哑铃形偏压长柱极限承载力研究

RESERCH ON ULTIMATE LOAD-CARRYING CAPACITY OF CONCRETE FILLED STEEL TUBULAR DUMBBELL SHAPED LONG COLUMNS UNDER ECCENTRIC LOAD

  • 摘要: 以长细比和偏心率为参数,进行了共16根钢管混凝土哑铃形偏压柱的试验。介绍了试验过程和试件的破坏形态,对试件的荷载-变形曲线、极限承载力等进行了分析。试验结果表明:钢管混凝土哑铃形偏压长柱属整体破坏,其极限承载能力和弹塑性阶段的切向刚度随着构件长细比和偏心率的增加而降低。建立了有限元模型,对哑铃形偏压长柱进行了受力全过程和极限承载力分析。分析表明:长细比和偏心率两个参数对钢管混凝土哑铃形偏压柱极限承载力的影响基本上是独立的,可以采用分项系数相乘来考虑二者的共同影响。稳定系数的计算公式可采取与哑铃形轴压长柱相同的计算公式。偏心率折减系数可采用本文通过对试验数据和有限元计算数据的回归拟合出的计算公式。

     

    Abstract: Total of 16 CFST dumbbell shaped columns subjected to eccentric loads were tested with variation of slenderness ratio and eccentricity ratio. The test procedure and the failure modes of specimens are introduced, and the load-deflection curves, ultimate load-carrying capacity are obtained. Test results indicate that the specimens fail in global buckling, and their ultimate load-carrying capacities and the tangential stiffness in elastic-plastic phase decrease with the increase of the slenderness ratio and the eccentricity ratio. Furthermore, finite element models are established to analyze the behavior of CFST dumbbell shaped long columns under eccentric loads, showing that the effect of slenderness ratio to load-carrying capacity and that of eccentricity ratio are independent, so their total effect can be accounted by a multiplication of individual effect. The calculation of stability coefficient is identical to that of long axial columns. The eccentric reduction coefficient can be predicted by the proposed formula from regression analysis of both experimental and computational results.

     

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