LOCAL BUCKLING OF SQUARE CONCRETE-FILLED STEEL TUBULAR COLUMN WITH BINDING BARS UNDER AXIAL LOADING

Assumed that the steel plate is subjected to spring constrain at the unloading edge, the formulae for calculating local buckling strength of the steel plate of square concrete-filled steel tubular column under axial loading are deduced using energy approach, the validity of which was verified with experimental results. A further analysis on the effect of binding bars on local buckling of steel plate shows that the binding bars can enlarge the coefficient of local buckling and improve the capacity of steel plate to resist local buckling. Proper spacing of binding bars and appropriate limitation for width-thickness ratio of steel tube are suggested for square concrete-filled steel tubular column with binding bars under axial loading.