Pipe joist is a lattice structure made of round rod members connected with each other at the end. The trusses make the truss structure economical in material and light in weight, and can be easily formed into various shapes to suit different purposes, such as simple truss, arch, frame and tower.
In recent years, with the continuous growth of steel production in China, pipe joist is more and more widely used and takes up a larger and larger proportion in the construction, such as industrial plants, equipment platform production line of automobile industry, logistics and storage, public building gymnasium, business club, high-speed railway platform, subway platform and high-rise business building. Steel pipe structure has also made a big breakthrough. The biggest advantage of steel pipe structure is that it can perfectly combine people's functional requirements, aesthetic requirements and economic efficiency requirements for buildings.
Compared with the mesh structure, the tube truss structure can meet the requirements of various building forms by eliminating the longitudinal bars of the lower chord and the ball nodes of the mesh, especially the construction of round arches and arbitrary curved shapes is more advantageous than the mesh structure. It has the same stability in all directions and saves material consumption. Steel pipe joist structure is developed on the basis of net frame structure, which has its unique superiority and practicality compared with net frame structure, and the structural steel consumption is more economical. Compared with the traditional open section (H-beam and I-beam) steel joist, the material of the cross section of pipe joist structure is more uniformly distributed around the neutral axis, so that the cross section has good compressive and torsional load capacity and large stiffness at the same time, without nodal plate, and simple construction. The most important thing is the beautiful appearance of pipe joist structure, which is easy to model and has certain decorative effect. It is easy to make, install, turn over and lift. The steel pipe roof frame made of cold-formed thin-walled section steel has the advantages of light structure, good stiffness, saving steel and giving full play to material strength, especially in the pressure rod and support system controlled by the length-to-slend ratio. The buildings with this structure are basically public buildings. The structure has the characteristics of beautiful shape (can be built into flat plate shape, round arch shape, any curve shape), easy production and installation, good structural stability, roof rigidity, good economic effect, etc.
