Two columns used to connect the steel structure, including a circular tube, two connecting plates, and a connecting part that connects one end to the outer circumference of the circular tube and the other end to one end of the connecting plate; Both the circular tube and the connecting plate are in smooth transition with the connection part. The plate surface of the connecting plate is parallel to the axis of the circular tube. The connecting plate is provided with a through hole for connecting the column Because hollow circular tubes are used as the bearing part of the connection between two upright columns, the hollow circular tubes with the same quality have the ability to resist bending moment and torsional moment greater than the solid rods, that is, their stiffness is greater than the solid rods. Therefore, the circular tube tie rods of the utility model can increase the overall stiffness of the two upright columns without increasing the supporting load of the columns too much; In addition, due to the smooth transition between the connection part and the connecting plate, the connection part of the round pipe will not break due to stress concentration when subjected to various loads, thus increasing the strength of the whole round pipe tie bar.
