Bearing capacity of UHPC-filled circular steel tube short column under axial compression

This study establishes a predictive formula for the axial compression bearing capacity of Ultra High Performance Concrete (UHPC) filled circular steel tube (circular UHPCFST) short columns. The basis for establishing this formula is the derivation method of the axial compression-bearing capacity formula for common concrete-filled circular steel tube short columns and relevant research. To verify the rationality of the formula, a finite element model of the axial compression of circular UHPCFST short columns was established, and the current axial compression bearing capacity test values of the circular UHPCFST short columns were used for the simulation. These results indicate that the proposed formula can accurately predict the axial compression bearing capacity of circular UHPCFST short columns. Compared with the axial compression bearing capacity formula of circular UHPCFST short columns in other studies, the coefficient of variation of the formula in this study is reduced by 21.10 % to 115.73 %, which proves that the formula in this study is less discrete and has better applicability. It was found that the interaction between the steel tube and UHPC was desirable, and the increase in the diameter-thickness ratio weakened the composite action of the section.