Concrete-filled steel tubular (CFT) columns have been widely used as structural members in buildings and bridges in recent years, because of their properties, such as high strength and stiffness, good ductility, and convenience for construction. In CFT columns, the bearing capacity of columns is inversely related to buckling, therefore, buckling is of particular importance at these sections, the AISC Code uses effective bending rigidity (EI_effective) to calculate the critical buckling load in concrete filled steel columns, to apply the effect of reducing concrete confinement, the AISC code provides a maximum value of 0.9 of the reduced concrete confinement coefficient for the equation. Effective bending rigidity (EI_effective), this relationship is provided in AISC code for circular and square sections, therefore, the effect of the column shape geometry on the core concrete confinement is very influential and changes the effective bending rigidity (EI_effective) of the section. The AISC code does not provide a coefficient to consider the type of cross-sectional geometry in CFT columns, therefore, in this study, three groups experimental, numerical (FEM) and theoretical were used to provide critical buckling load correction, finally, it was concluded that the critical buckling load for the cross-section (L) shape due to the lower confinement of the concrete core is 20.07% lower than the AISC code equation, also with a 67% increase in slenderness ratio, the critical buckling load decreased by 14.52%.

近年来，钢管混凝土（CFT）柱由于具有诸如高强度和刚度，良好的延展性以及易于施工等特性而被广泛用作建筑物和桥梁的结构构件。在CFT柱中，柱的承载能力与屈曲成反比，因此，在这些截面上屈曲尤为重要，AISC规范使用有效抗弯刚度（EI_有效）来计算钢管混凝土柱的临界屈曲载荷，如果应用减小混凝土约束的效果，则AISC代码为方程式提供了最大为0.9的减小的混凝土约束系数。有效弯曲刚度（EI_有效），此关系在圆形截面和方形截面的AISC代码中提供，因此，圆柱形状几何形状对核心混凝土约束的影响非常大，并且会改变截面的有效抗弯刚度（EI_有效）。AISC代码没有提供考虑CFT柱中横截面几何类型的系数，因此，在这项研究中，使用了三组实验，数值（FEM）和理论组来提供临界屈曲载荷校正，最后，得出的结论是，由于混凝土芯的较低约束，横截面（L）形状的临界屈曲载荷比AISC代码方程低20.07％，而且细长比增加了67％，临界屈曲载荷下降了14.52％。