An Investigation into the Strength of Concrete-Filled Tubes

The design strength of concrete-filled tubes (CFT) is being calculated based on two approaches including the AISC and ACI methods. The AISC applies the steel column formulas with the use of coefficients for transforming the concrete into steel to determine the CFT design strength. The design strength of AISC is being evaluated through the use of two approaches including the plastic stress distribution and strain compatibility methods. This study used both the plastic stress distribution and strain compatibility methods to calculate the design strength of CFT, and compare the design strengths using these two methods. This study presents a more accurate numerical approach to evaluate the CFT columns including rectangular and square sections. The illustrated example is presented to demonstrate the step-by-step procedure to obtain the CFT design strength based on the AISC Specification. The provided design procedure for the strength evaluation of CFT columns enables those who need a better estimation on the CFT axial strengths based on the AISC Specification.