新型哑铃形轴压长柱面外力学性能分析

Out-of-plane mechanical properties analysis of new type dumbbell-shaped long columns under axial loads

对不同长细比的新型哑铃形钢管混凝土轴压长柱进行了试验研究.结果表明,在加载过程中,试件的弹塑性和延性都很好,失稳模式为整体失稳.与传统哑铃形长柱相似,试件的面外极限承载力和弹塑性阶段切向刚度均随着试件长细比的增大而减小.在长细比相同情况下,新型哑铃形轴压长柱由于中间部分H型钢加劲的联结形式,其面外稳定性远强于其两肢单圆管轴压长柱.对新型哑铃形轴压长柱的面外极限承载力计算方法进行了探讨,结果显示等效单圆管法的计算结果与试验结果更为接近.

In order to research the out-of-plane mechanical properties of new type dumbbell-shaped long columns under axial loads,experiment with different slenderness ratio was carried out.The theoretical analysis on the test results indicated that the elasitc-plastic capability and ductility of specimens were very good and the instability mode was belong to entire buckling.Similar to that in the traditional dumbbell-shaped long columns,out-of-plane load-carrying capacity and the tangential stiffness in elastic-plastic phase of the specimens decreased with the increase of slenderness ratio.On the condition of similar slenderless ratio,the stability of the specimens is far stronger than the single-circular-tube long column under axial loads at the out-of-plane direction with the result of fastening by H-type steel between two single circular tubes.The method to calculate the out-of-plane load-carrying capacity of new-type dumbbell-shaped long columns was discussed,the result denoted that the calculation data calculated by the equivalent-single-circular-tube method agrees well with the experimental ones and it is suggested to use in engineering practice.