| In this paper, the theoretical derivation and analysis of the local buckling of steel plates in square CFT with or without binding bars under axial and eccentric compression is proposed. The main research contents and results are as follows.(1)Assumed that the four edges of steel plate in square CFT are clamped based on the existing experimental and theoretical research. The critical local buckling stress of steel plates in square CFT under axial and eccentric compression is derived based on finite strip method. The simplified calculation formula of critical buckling coefficient is proposed by nonlinear fitting. The calculated value is in good agreement with the existing theory. Reasonable width-thickness ratios are suggested which to ensure that CFT yield before the local buckling occurs.(2)Based on local buckling characteristics of steel plates in axially and eccentrically loaded square CFT columns with binding bars, the effectively confined core of binding bars is defined. Furthermore, the local buckling model of axially and eccentrically loaded square CFT columns with binding bars is proposed. Based on the proposed model, local buckling stress of steel plates in axially and eccentrically loaded square CFT columns is calculated. The simplified formula of buckling coefficient in the effectively confined core of binding bars is proposed which error is less than 1 percent.(3)Calculated values of critical local buckling stress are compared with experimental results, which showing good agreement. The local buckling model based on finite strip method is applicable to local buckling analysis.(4)The effects of horizontal spacing, longitudinal spacing and diameter of binding bars on overall average critical local buckling stress are investigated based on the proposed model. It is found that the effects of longitudinal spacing on the overall average critical local buckling stress is the most significant, while the effects of diameter of binding bars is the least. Furthermore, the effects of horizontal spacing of binding bars are between the effect of longitudinal spacing and the diameter of binding bars. Finally, reasonable limitations for width-to-wall thickness ratio of steel plates at various binding bar spacing are proposed based on parameter studies, which can be applied in engineering design. |
