Study on the axial ultimate bearing capacity of square concrete-filled steel tubular stub columns

Based on unified strength theory,the mechanical behavior of effective restriction-area and ineffective restriction-area of coreconcrete of square concrete-filled steel tubular stub columns was analyzed.Through controlling the restriction effect between square steel tube and core-concrete by width-thickness ratio,a ultimate bearing capacity formula for square concrete-filled steel tubular stub columns under axial compression is proposed,and the influencing factors of which is also discussed.And the method is expanded to calculate other different kinds of concrete-filled steel tubular stub columns.By comparing the results of proposed formula with that of experiments,the rationality of proposed formula is proved.And the solution may have some important practical value.