Analysis on the ultimate bearing capacity of self-stress lightweight concrete filled steel tubular columns

The bearing capacity of steel tube is derived based on the twin shear unified strength theory.The effects of the intermediate principal stress on the circumferential tension and longitudinal compression are considered.The bearing capacity of core concrete is obtained in terms of the strength criterion of concrete in self-stress lightweight concrete filled steel tubular columns in the literature.The ultimate capacities of steel tubular columns are then derived by combination between the capacity of steel tube and core concrete.The results indicates that the bearing capacity increases with the increasing of coefficient b.Good agreements can be observed from the comparison between the results obtained and experimental data.