Study on seismic behavior of steel tube-reinforced concrete transfer columns based on finite element method

This paper simulates the experiment of 108 steel tube-reinforced concrete transfer columns(STRC-RC) specimens with different parameters under low reversed cyclic loading using finite element software ABAQUS. The study results show that: the extension length of steel tube has little effect on bearing capacity, but has great effect on displacement ductility. The bearing capacity of the transfer columns firstly increases and then decreases, the displacement ductility decreases with an increase of axial load ratio. At the same times, larger axial load ratio restrains the development of bending deformation to result in more poor ductility and deformation capacity. Instead, the load capacity of the transfer columns increases, the displacement ductility coefficient firstly increases and then decreases with an increase of steel ratio, so reasonable steel ratio should be ensured. By increasing the steel reinforcement ratio, the bearing capacity of the STRC-RC transfer columns improves significantly, but has little effect on displacement ductility. Changing reinforcement style does not obviously affect the bearing capacity and displacement ductility of transfer columns. Failure patterns of the transfer columns can be divided into Shear failure and bend failure. Shear failure easily occurs in the transfer columns that with shorter extension length of steel tube, higher axial compression ratio and higher reinforcement ratio. More stirrups at the position where steel tube is cut off can effectively control the development of shear crack.