It is named because its section is the same as the English letter “H”. Because all parts of H-section steel are arranged at right angles, H-section steel has the advantages of strong bending resistance, simple construction, cost saving and light structural weight in all directions, and has been widely used.
H-section steel is a new type of steel for economic construction. The section shape of H-section steel is economical and reasonable, with good mechanical properties. During rolling, each point on the section extends evenly and the internal stress is small. Compared with ordinary I-section steel, H-section steel has the advantages of large section modulus, light weight and metal saving, which can reduce the building structure by 30-40%;
Because the inner and outer sides of its legs are parallel and the leg ends are right angles, it can be assembled into components, which can save 25% of the workload of welding and riveting.
It is often used in large buildings (such as plants, high-rise buildings, etc.) requiring large bearing capacity and good section stability, as well as bridges, ships, hoisting and transportation machinery, equipment foundations, supports, foundation piles, etc.
H-section steel is a kind of economical section steel with better section mechanical properties, which is optimized and developed from I-section steel.
In particular, the section is named after the English letter “H”. Its features are as follows:
◆ wide flange and large lateral stiffness.
◆ strong bending resistance, about 5% – 10% higher than I-beam.
◆ the two surfaces of the flange are parallel to each other, making it easy to connect, process and install.
◆ compared with welded I-beam, it has the advantages of low cost, high precision and small residual stress. It does not need expensive welding materials and weld detection, saving about 30% of the manufacturing cost of steel structure.
◆ under the same section load, the weight of hot-rolled H steel structure is 15% – 20% less than that of traditional steel structure.
◆ compared with the concrete structure, the hot-rolled H steel structure can increase the service area by 6%, reduce the self weight of the structure by 20% – 30%, and reduce the structural design internal force.
◆ H-section steel can be processed into T-section steel, and honeycomb beams can be combined to form various section forms, which greatly meets the needs of engineering design and manufacturing.
◆ steel structure bearing support of industrial structures
◆ steel piles and supporting structures of underground works
◆ structure of petrochemical, electric power and other industrial equipment
◆ large span steel bridge components
◆ ship and machinery manufacturing frame structure
◆ girder support of train, automobile and tractor
◆ port conveyor belt, high-speed baffle support
H-section steel is a kind of economical section steel, which is widely used in industry, construction, bridges, oil drilling platforms, etc. it is predicted that the demand for H-section steel in China will be about 2.5 million tons in 2005 and 5 million tons in 2010.
However, at present, the annual production capacity of H-section steel in China is 1.2 million tons, and the market demand is very huge.
1. High structural strength
Compared with I-beam, the section modulus is large. When the bearing conditions are the same, the metal can be saved by 10-15%.
2. Flexible and rich design style
When the beam height is the same, the bay of steel structure can be 50% larger than that of concrete structure, so as to make the building layout more flexible.
3. Light structure weight
Compared with the self weight of concrete structure, it is light, the self weight of structure is reduced, the internal force of structural design is reduced, and the foundation treatment requirements of building structure are low, the construction is simple and the cost is reduced.
4. High structural stability
The steel structure dominated by hot-rolled H-section steel has scientific and reasonable structure, good plasticity and flexibility and high structural stability.
It is suitable for building structures bearing large vibration and impact loads and has strong resistance to natural disasters. It is especially suitable for building structures with many earthquake occurrence zones.
According to statistics, among the devastating earthquake disasters with m ≥ 7 in the world, the steel structure buildings dominated by H-section steel suffer the least.
5. Increase the effective use area of the structure
Compared with concrete structure, the cross-sectional area of steel structure column is small, which can increase the effective use area of the building. Depending on different forms of buildings, it can increase the effective use area by 4-6%.
6. Save labor and materials
Compared with welded H-section steel, it can obviously save labor and materials, reduce the consumption of raw materials, energy and labor, have low residual stress and good appearance and surface quality.
7. Convenient for machining
It is easy to connect and install the structure, and easy to remove and reuse.
8. Environmental protection
The use of H-section steel can effectively protect the environment, which is embodied in three aspects:
first, compared with concrete, dry construction can be used, resulting in less noise and dust; Second, due to the reduction of self weight, less soil is taken for foundation construction and less damage to land resources.
In addition, the amount of concrete is greatly reduced and the amount of rock excavation is reduced, which is conducive to the protection of ecological environment;
Third, after the service life of the building structure expires and the structure is removed, the amount of solid waste generated is small and the recycling value of waste steel resources is high.
9. High degree of industrialized production
The steel structure mainly made of hot-rolled H-section steel has a high degree of industrialization, which is convenient for mechanical manufacturing, intensive production, high precision, convenient installation and easy quality assurance.
It can build a real house manufacturing factory, bridge manufacturing factory, industrial plant manufacturing factory, etc. The development of steel structure has created and driven the development of hundreds of emerging industries.
10. Fast construction speed
It covers a small area, is suitable for all-weather construction, and is less affected by climatic conditions.
The construction speed of steel structure made of hot-rolled H-section steel is about 2-3 times that of concrete structure, the capital turnover rate is doubled, the financial cost is reduced, and the investment is saved.
◆ I-section steel, whether ordinary or light, is relatively high and narrow in section size, so the moment of inertia of the two main sleeves of the section is quite different.
Therefore, it can only be directly used for members bent in the plane of their web or form lattice stress members.
It is not suitable for axial compression members or members with bending perpendicular to the web plane, which makes it very limited in the scope of application.
◆ H-section steel belongs to high-efficiency and economic cutting profile (other cold-formed thin-wall section steel, profiled steel plate, etc.).
Due to the reasonable section shape, they can make the steel more effective and improve the bearing capacity.
Different from the ordinary I-section, the flange of H-section steel is widened, and the inner and outer surfaces are usually parallel, so it is convenient to connect with other components with high-strength bolts.
The size composition series is reasonable and the models are complete, which is convenient for design and selection.
◆ the flange of H-beam is of equal thickness, including rolling section and combined section composed of three plates welded. All I-beams are rolled sections.
Due to poor production technology, the inner edge of the flange has a slope of 1:10. The rolling of H-beam is different from that of ordinary I-beam.
Only one set of horizontal rolls is used. Because its flange is wide and has no inclination (or the inclination is very small), a group of vertical rolls must be added for rolling at the same time.
Therefore, its rolling process and equipment are more complex than ordinary rolling mills. The maximum height of rolled H-section steel that can be produced in China is 800mm, which exceeds the welded composite section.
According to the national standard of hot rolled H-section steel in China (GB / t11263-1998), H-section steel is divided into three categories: narrow flange, wide flange and steel pile, whose codes are Hz, HK and Hu respectively.
Narrow flange H-section steel is suitable for beams or bending members, while wide flange H-section steel and H-section steel pile are suitable for axial compression members or bending members.
Compared with H-section steel, W, IX and iy are not as good as H-section steel under the premise of equal weight.