Simplified calculation method for eccentric compressive capacity of diagonal-rib stiffened square concrete-filled steel tubular columns

To study the calculation method for the eccentric compressive capacity of the diagonal rib stiffened square concrete-filled steel tube column, its eccentric compressive capacity was expressed by a formula relating eccentric plastic bearing capacity of the cross-section and eccentric critical compressive capacity of the column, based on the geometric relationship in the axial force-moment interaction curves of the cross section and the column. Eccentric plastic bearing capacity of the cross-section was calculated by plastic stress analysis methods and eccentric critical compressive capacity of the column was derived from stability theories. The constraint effect of diagonal ribs on concrete and the second-order effect were considered in the calculation. The research results show that the average ratios of the eccentric compressive capacity of the diagonal-rib stiffened square concrete-filled steel tubular column calculated by the proposed method to the results obtained from experiments and finite element parametric analysis are 0. 94 and 0. 90, respectively. Corresponding standard deviations are both 0. 06, which indicates that the proposed method exhibits good accuracy and safety. The proposed method is suitable for columns with small eccentric compression failure. The predicted results by the proposed method are slightly conservative for columns with small height-width ratios, while more accurate for columns with large height-to-width ratios. © 2023 Science Press. All rights reserved.