Steel structure is a type of steel structure and one of the most important building types. The structure mainly consists of steel beams, columns, trusses and other profiles, as well as steel structures, using anti-corrosion and anti-corrosion processes such as silicification, pure manganese phosphating, cleaning, drying, and galvanizing. Screws or rivets are usually used to secure parts or components. It is lightweight and has a simple structure, suitable for large workshops, sports fields, skyscrapers, etc. 
Steel has the characteristics of high strength, light weight, good overall strength, and strong deformation ability. Therefore, it is particularly suitable for the construction of large, ultra large, and ultra heavy buildings; This material is an ideal elastic material with good uniformity and isotropy, which best conforms to the basic assumptions of general technical mechanics. It has good ductility and strength, can have significant deformation, and can withstand dynamic loads well; Short construction time, high degree of industrialization, high degree of specialization and mechanization in production.

Features:
1. High strength and light weight of the material
Steel has high strength and high modulus of elasticity. Since the density and the yield strength ratio are relatively low compared with the concrete and the wood, the steel structure is small in the cross section under the same load condition, and it is light weight, and it is convenient for transportation and installation, and it is suitable for large span, high altitude and large load structure..
2.  Good toughness, good plasticity, uniform material and high structural reliability of the steel
It has good seismic performance and can withstand impact and dynamic load. The internal structure of the steel is uniform and almost isotropic. The actual performance of the steel structure is more consistent with the computation theory, so the reliability of the steel structure is very high.
3. High extent of mechanization of steel structure manufacturing and installation
Steel structural members are easy to manufacture in factories and assemble on site. Steel structure component factories have advantages such as high precision, high production efficiency, fast assembly speed, and short construction period. Steel structures are the most industrialized structures.
4. Great sealed performance of steel structure
The welded structure can be completely sealed, so it can be made into high-pressure storage tanks, large oil tanks, pressure pipes, etc. with good air and water sealing properties.

5. Structural steel with heat resistant, not fire resistant
When the temperature is under 150 ℃, the performance of the steel remains almost unchanged, so steel structures are suitable for high-temperature workshops, but when the surface of the structure is exposed to thermal radiation of about 150 ℃, insulation boards should be used for protection. When the temperature is between 300 ℃ and 400 ℃, the strength and elastic modulus of steel significantly decrease. When the temperature is around 600 ℃, the strength of the steel tends to zero. In buildings with special fire protection requirements, steel structures must be protected with refractory materials to improve their fire resistance rating.
6.Low corrosion resistance of steel structure
Especially under the wet and corrosive environment, it is easy to rust. General steel structures need to be derusted, galvanized or painted, and require regular maintenance. For offshore platform structures in seawater, special measures such as"zinc block anode protection"should be taken to prevent corrosion.
7. Low-level carbon, energy saving, green environmental protection, reusable
Demolition of steel structures produces little construction waste, and steel can be recycled.

Application program:
Steel structures have the advantages of better uniformity, higher strength, faster construction speed, better seismic performance, and higher recovery rate compared to common reinforced concrete structures. The strength and elastic modulus of steel are many times that of bricks and concrete. Under the same conditions, the weight of steel components is lighter. From the perspective of damage, steel structures have significant early deformation precursors and belong to ductile failure structures, which can be detected in advance to avoid danger.
The work of the iron structure has light heavy profits, economic foundations, some materials, low costs, short construction time, large-scale, safety and trust, beautiful appearances, and stable structures. The work of the iron structure is widely used in large industrial buildings, warehouses, refrigerators, high buildings, office buildings, multi-level car parks; It applies to the residential building and other construction industries.

Steel structure installation:
Prefabricate of steel components:
According to the installation sequence and process requirements, the prefabrication and assembly of steel components need to be carried out on a steel platform, and welding quality must be ensured.
The distance between the flange connection and the steel core connection must exceed 200 mm. The length of the flange joint should not be less than twice the width of the plate. The width and width of the joint should not exceed 300 mm and 600 mm, respectively.
According to the dimensions of the construction drawings, butt welding should be carried out on the steel platform on the ground as much as possible to ensure welding quality, and butt welding should be carried out on the stiffeners, connecting plates, base plates, and beams (beams) on the columns and beams as much as possible.
Besides fabrication and assembly of precast steel members on steel platforms in accordance with construction drawings and specifications, manufacturability of field installation and variation in installation dimensions should also be considered.