Evaluation of AISC 360-16 and Eurocode 4 Compressive Strength Equations for Concrete-Filled Steel Tube Columns

This paper presents a review and evaluation of the AISC 360-16 and Eurocode 4 strength prediction equations for concrete-filled steel tube (CFST) columns subjected to axial compression.A new experimental database of CFST column test results is compiled from the published technical literature from year 1988 to present.The database includes up-to-date research data of which column properties are outside the specification or code limitations.A total of 335 and 257 columns of different properties regarding the material strength, column size and slenderness, confinement factor, and steel tube fabrication method (only for square CFST) are used to evaluate the accuracy and conservativeness of the predictions for circular and square CFST columns.It is found that the AISC 360-16 strength equations conservatively predict the compressive strength of circular CFST columns even the tube slenderness exceeds the current specification limit, while the simplified method of Eurocode 4 is not recommended for square CFST columns when the yield strength of steel tube or tube slenderness ratio exceeds the code limits.Based on the strength prediction equations, the effectiveness of circular over square CFST columns is more realized in Eurocode 4 than AISC360-16.The predicted circular-to-square column strength ratio increases as confinement factor increases, while it decreases as column length-to-depth ratio increases.Based on the experimental database, the effect of column sizes on the normalized strength of circular CFST columns is also investigated.The different tendency of the size effect is found when the confinement factor changes.