钢管混凝土柱极限承载力分析的分段合成法

Integral method for ultimate load analysis of concrete-filled steel tubular columns

在计算钢管混凝土受压构件弹塑性极限承载力的合成法基础上,提出了一种新的数值计算方法———分段合成法,计算假设仅包括平截面假设和考虑紧箍力影响的钢管混凝土的应力-应变关系,取消了原合成法中对柱变形曲线的假设,积分时不仅需要在截面上划分单元而且还需沿杆长划分单元,因而可考虑柱多个截面的平衡条件.与原合成法相比,该方法不仅适用于轴压构件和两端偏心距相等的偏压构件,而且还适用于两端偏心距不等的偏压构件的弹塑性极限承载力计算.利用提出的方法和程序,计算了圆形截面钢管混凝土轴压长柱、两端偏心距相等的偏压长柱以及两端偏心距不等的偏压长柱的弹塑性极限承载力,理论分析结果与文献中的理论结果和试验结果均吻合良好.

Based on the synthesis method for calculating elastic-plastic ultimate load of concrete-filled steel tubular columns, a new numerical method is put forward. Hypotheses in the calculation only include the cross-section plane hypothesis and the stress-strain relation of steel and concrete with a consideration of the interaction effect between the steel tube and the core concrete, and the assumption on the deformation curve of the original synthesis method is removed. As in this new approach, the elements are divided not only on the cross-section but also along the column length, the balance conditions of multiple cross-sections can be taken into consideration simultaneously. Comparing the original method, the current method is suitable for calculating the ultimate load of not only axial compression columns and eccentrically loaded columns with equal eccentricity, but also eccentrically loaded columns with unequal eccentricity. The ultimate loads of some axial compression columns, eccentrically loaded columns with equal eccentricity and eccentrically loaded columns with unequal eccentricity are computed using the program. And the results show that the present results agree well with experimental and theoretical results in literature.