2024 Volume 70B Pages 257-263
In AIJ CFT Recommendations, the full plastic flexural strength is used as the ultimate flexural strength of the CFST beam-columns. The ultimate flexural strength of rectangular CFST beam-columns is calculated using a concrete strength reduction factor of cru = 1.0, and that of circular CFST beam-columns is calculated considering the confined effect between the filled-concrete and steel tube. However, when the loading condition of the CFST beam-columns are pure bending, the design ultimate strength may overestimate the experimental values even if all experimental parameters are within the scope of the CFT Recommendations.
For the practical beam-columns subjected to flexural shear, the lateral load carrying capacity may increase by around 10% due to the end constraint, and other conditions. Therefore, it can be evaluated on the safe side under flexural shear loading condition, even if the flexural strength ratio between the experimental value and design strength is 0.9 under pure bending condition. However, the increase in flexural strength due to the end constraint under flexural shear condition has not been examined.
This study discussed the effect of end constraint on ultimate flexural strength of concrete-filled steel tubular beam-columns.
