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Practical formula for predicting axial strength of circular-CFST columns considering size effect
Abstract A practical and accurate unified formula for predicting the axial compressive strength of short-long circular CFST columns is proposed based on the regression analysis of 368 available experimental data. The formula is applicable to large, thin-walled, and high-strength circular CFST columns, which was established through two processes: (1) Based on 273 experimental data of short specimens, the axial strength of short columns was determined numerically and normalized with respect to the yielding load of the steel tube, thus showing a superior exponential correlation with the modified confinement index ξ; and (2) The numerical model was improved by considering the effect of length-to-diameter (L/D) ratio for long columns. According to the parametric analysis, the size effect is found to have a certain influence on the axial strength of large CSFT short columns and the primary affecting factors to the size effect are the compressive strength of in-filled concrete (f c) and the outer diameter to thickness (D/t) ratio of the steel tubes. Therefore, the size effect is better to be considered in a strength model, as proposed. The strength reduction caused by the size effect is characterized by ξ which involves the parameters of f c, D, and t. In comparison with the measured strengths from the test specimens, the proposed prediction model provides a more accurate and stable estimate on column design strength than the existing design codes.
Highlights Proposed a practical strength formula of circular CFST columns under compression. High accuracy in evaluation of axial strength of short to slender column. Proposed formula can be applied to large-size, thin-walled and high-strength columns. Axial strength model of circular CFST short column considers the size effect. Concrete strength and D/t ratio control the size effect of circular CFST stub column.
Practical formula for predicting axial strength of circular-CFST columns considering size effect
Abstract A practical and accurate unified formula for predicting the axial compressive strength of short-long circular CFST columns is proposed based on the regression analysis of 368 available experimental data. The formula is applicable to large, thin-walled, and high-strength circular CFST columns, which was established through two processes: (1) Based on 273 experimental data of short specimens, the axial strength of short columns was determined numerically and normalized with respect to the yielding load of the steel tube, thus showing a superior exponential correlation with the modified confinement index ξ; and (2) The numerical model was improved by considering the effect of length-to-diameter (L/D) ratio for long columns. According to the parametric analysis, the size effect is found to have a certain influence on the axial strength of large CSFT short columns and the primary affecting factors to the size effect are the compressive strength of in-filled concrete (f c) and the outer diameter to thickness (D/t) ratio of the steel tubes. Therefore, the size effect is better to be considered in a strength model, as proposed. The strength reduction caused by the size effect is characterized by ξ which involves the parameters of f c, D, and t. In comparison with the measured strengths from the test specimens, the proposed prediction model provides a more accurate and stable estimate on column design strength than the existing design codes.
Highlights Proposed a practical strength formula of circular CFST columns under compression. High accuracy in evaluation of axial strength of short to slender column. Proposed formula can be applied to large-size, thin-walled and high-strength columns. Axial strength model of circular CFST short column considers the size effect. Concrete strength and D/t ratio control the size effect of circular CFST stub column.
Practical formula for predicting axial strength of circular-CFST columns considering size effect
Yang, Chang (Autor:in) / Gao, Pan (Autor:in) / Wu, Xingxiang (Autor:in) / Chen, Y. Frank (Autor:in) / Li, Qi (Autor:in) / Li, Zhao (Autor:in)
04.02.2020
Aufsatz (Zeitschrift)
Elektronische Ressource
Englisch
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