The larger the structural span, the greater the proportion of self-weight in the load. Reducing the self-weight of the structure brings significant economic benefits. The advantages of high steel strength and light structure weight are well-suited to large-span structures. Therefore, steel structures are widely used in large-span spatial structures and large-span bridge structures. The structural forms used include spatial trusses, reticulated structures, reticulated shells, suspension structures (including cable-stayed systems), arch beams, solid or latticed arches, and frames, etc.

 

 

　　The main load-bearing frames of workshops with large crane lifting capacities or heavy-duty operations often use steel structures. In addition, workshops with strong radiant heat also often use steel structures. The structural forms are mostly portal frames or rafter frames composed of steel trusses and stepped columns, and there are also structures using reticulated structures as roofs.

 

　　In recent years, with the adoption of lightweight roofing materials such as profiled steel sheets, light steel structure industrial plants have developed rapidly. The main structural form is a solid-web variable-section portal frame.

 

 

　　Because steel has good toughness, even if the truss span is not large, factories with large forging hammers or other equipment that produce dynamic effects are often made of steel. Steel structures are also suitable for structures with high seismic resistance requirements.

 

 

　　Due to the excellent comprehensive benefit indicators of steel structures, they have been widely used in multi-story and high-rise civil buildings in recent years. The main structural forms include multi-story frames, frame-support structures, box tubes, suspension structures, and giant frames, etc.

 

 

　　Tall structures include towers and mast structures, such as towers for high-voltage transmission lines, towers and masts for broadcasting, communication, and television transmission, and rocket (satellite) launch towers, etc.

 

 

　　Steel structures are not only lightweight but can also be connected using bolts or other easy-to-disassemble methods. Therefore, they are very suitable for structures that need to be relocated, such as the skeletons of buildings under construction, oil fields, and production and living quarters for field operations, etc. The formwork and scaffolding used in reinforced concrete structure construction, as well as the scaffolding used in building construction, are also largely made of steel.

 

 

　　Metallurgical, petroleum, and chemical enterprises use a large number of steel plate containers, including oil tanks, gas tanks, blast furnaces, hot blast furnaces, etc. In addition, frequently used steel structures include belt conveyor walkways, pipe supports, boiler supports, etc. Offshore oil platforms are mostly made of steel structures.

 

 

　　The light weight of steel structures is not only beneficial for large-span structures but also for small-span structures with particularly light roof live loads. Because when the roof live load is particularly light, the self-weight of the small-span structure also becomes an important factor. Under certain conditions, the steel consumption of cold-formed thin-walled steel trusses can be less than that of reinforced concrete trusses. The structural forms of light steel structures include solid-web variable-section portal frames, cold-formed thin-walled steel structures (including metal corrugated roofs), and steel pipe structures, etc.

 

 

　　Steel components and plates must meet stability requirements when under compression, often unable to fully utilize their high strength. Concrete, however, is best suited for compression and not for tension. Combining steel and concrete allows both materials to fully utilize their strengths, making it a very reasonable structure. In recent years, this type of structure has made significant progress in China and is widely used in high-rise buildings (such as the SEG Plaza in Shenzhen), large-span bridges, industrial plants, and subway station columns, etc.