Calculation of the Interfacial Tensile Stress of CFST Members under Axial Pressure

Based on plane strain theory, the formula for calculating the tensile stress on the interface between the steel tube and concrete under the axial pressure was derived, and the stress distribution coefficient K was analyzed. Practical formula for calculating the interfacial tensile stress of CFST members under low stress condition was fitted. Using the fitted formula the interfacial stress calculation process can be greatly simplified, and the results have enough assurance. This formula can be easily applied to CFST members’ interfacial stress calculation.