1. The geometric characteristics of the pipe section are good, the pipe wall is thin, the material of the section is distributed around the centroid, the radius of gyration of the section is large, and it has strong torsional rigidity; as a member under compression, bending and bidirectional bending, its bearing force is higher, and the straightness of cold-formed pipe and the accuracy of section size are better than hot-rolled open section.

2. In terms of anti-hydrodynamic characteristics, the cross section of the round tube is good, and the effect of wind and water flow is reduced. The rectangular tube section is similar to other open sections in this respect.

3. The steel pipe is a closed section; when the average thickness and cross-sectional area are the same, the exposed surface area is about 50% to 60% of the open section, which is beneficial to corrosion prevention and can save coating materials.

4. The node connection is suitable for direct welding, without the node plate or other connecting parts, which saves labor and materials.

5. The appearance is more beautiful, especially the pipe truss composed of steel pipe components, without redundant joints, and has a strong modern feel.

6. When necessary, concrete can be poured into the pipe to form a composite component.

Due to the above advantages, the longitudinally welded steel pipe structure can save about 20% of steel in industrial buildings and 50% in tower structures compared with structures made with open sections. The steel pipe structure can make round pipe structure or rectangular pipe structure according to the specific conditions of the component's stress, supply conditions, manufacturing and processing conditions, and cost. The two types of steel pipes can also be mixed.