First, the structural introduction of H-shaped steel:
H-shaped steel is a new type of economical steel for construction. The cross-sectional shape of H-shaped steel is economical and reasonable, with good mechanical properties. When rolling, the extension of each point on the cross section is relatively uniform and the internal stress is small. Compared with ordinary I-shaped steel, it has the advantages of large cross-sectional modulus, lightweight, and metal saving, which can reduce the building structure by 30-40%; and because its legs are parallel inside and outside, and the leg ends are right angles, it can be assembled into components, which can save 25% of welding and riveting work. It is often used in large buildings (such as factories, high-rise buildings, etc.) that require large cross-sectional capacity and good cross-sectional stability, as well as bridges, ships, lifting and transportation machinery, equipment foundations, brackets, foundation piles, etc.
H-shaped steel is an economical cross-sectional steel with better cross-sectional mechanical properties developed from the optimization of I-shaped steel, especially since the cross-sectional shape is the same as the English letter “H”. Its characteristics are as follows:
Wide flange and large lateral stiffness. Strong bending resistance, about 5%-10% higher than I-shaped steel. The two surfaces of the flange are parallel to each other, making connection, processing, and installation easy. Compared with welded I-beams, it has low cost, high precision, low residual stress, no need for expensive welding materials and weld inspection, and saves about 30% of the cost of steel structure production. Under the same cross-sectional load, the weight of the hot-rolled H-steel structure is 15%-20% lighter than that of the traditional steel structure. Compared with concrete structures, hot-rolled H-steel structures can increase the usable area by 6%, and the self-weight of the structure is reduced by 20% to 30%, reducing the internal force of structural design. H-shaped steel can be processed into T-shaped steel, and honeycomb beams can be combined to form various cross-sectional forms, which greatly meet the needs of engineering design and production.
Second, the application scope of H-shaped steel:
H-shaped steel is mainly used for beam and column components in industrial and civil structures.
①Steel structure load-bearing brackets for industrial structures
②Steel piles and support structures for underground projects
③Structures for industrial equipment such as petrochemicals and electric power
④Long-span steel bridge components
⑤Frame structures for ships and machinery manufacturing
⑥Girder brackets for trains, cars, and tractors
⑦Port conveyor belts and high-speed baffle brackets
H-shaped steel is an economical cross-section steel material, widely used in industry, construction, bridges, oil drilling platforms, etc. It is predicted that my country’s demand for H-shaped steel will be about 2.5 million tons in 2005 and 5 million tons in 2010, but my country’s annual production capacity for H-shaped steel is 1.2 million tons at present, and the market demand is very huge.
Third, what are the characteristics of H-shaped steel:
1. High structural strength: Compared with I-shaped steel, the section modulus is large, and under the same load-bearing conditions, it can save 10-15% of metal.
2. Flexible and rich design style: Under the same beam height, the span of the steel structure can be 50% larger than that of the concrete structure, making the building layout more flexible.
3. Light weight of the structure: Compared with the concrete structure, the reduction of the structure’s weight reduces the internal force of the structure design, which can make the building structure foundation treatment requirements low, the construction simple, and the cost low.
4. High structural stability: The steel structure mainly based on hot-rolled H-shaped steel has a scientific and reasonable structure, good plasticity and flexibility, high structural stability, and is suitable for building structures that bear large vibration and impact loads. It has strong resistance to natural disasters and is particularly suitable for building structures in some earthquake zones. According to statistics, in the world’s devastating earthquake disasters above magnitude 7, steel structures mainly based on H-shaped steel suffered the least damage.
5. Increase the effective use area of the structure: Compared with concrete structures, the cross-sectional area of steel structure columns is small, which can increase the effective use area of the building. Depending on the different forms of the building, the effective use area can be increased by 4-6%.
6. Save labor and materials: Compared with welded H-shaped steel, it can significantly save labor and materials, reduce the consumption of raw materials, energy, and labor, have low residual stress, and have good appearance and surface quality.
7. Easy to machine: Easy to connect and install the structure, and easy to dismantle and reuse.
8. Environmental protection: The use of H-shaped steel can effectively protect the environment, which is specifically manifested in three aspects: First, compared with concrete, dry construction can be used, which produces less noise and less dust; second, due to the reduced self-weight, the amount of soil taken for foundation construction is small, and the damage to land resources is small. In addition, the amount of concrete used is greatly reduced, and the amount of mountain excavation and stone excavation is reduced, which is conducive to the protection of the ecological environment; third, after the service life of the building structure expires and the structure is dismantled, the amount of solid waste generated is small, and the recycling value of scrap steel resources is high.
9. High degree of industrialization: The steel structure mainly based on hot-rolled H-shaped steel has a high degree of industrialization, which is convenient for mechanical manufacturing, intensive production, high precision, easy installation, and easy quality assurance. It can be built into a real house manufacturing factory, bridge manufacturing factory, industrial plant manufacturing factory, etc. The development of steel structures has created and driven the development of hundreds of emerging industries.
10. Fast construction speed: It occupies a small area is suitable for all-weather construction, and is less affected by climatic conditions. The construction speed of steel structures made of hot-rolled H-shaped steel is about 2-3 times that of concrete structures, and the capital turnover rate is doubled, which reduces financial expenses and saves investment.
Fourth, the difference between H-shaped steel and I-shaped steel:
I-shaped steel, whether ordinary or light, has a relatively high and narrow cross-sectional size, so the moment of inertia of the two main sleeves of the cross-section is quite different. Therefore, it can generally only be used directly for members that are bent in the web plane or to form a lattice-type load-bearing member. It is not suitable for axially compressed members or members that are bent perpendicular to the web plane, which greatly limits its application range.
H-shaped steel has a high-efficiency and economical cutting profile (others include cold-bent thin-walled steel, corrugated steel plates, etc.). Due to the reasonable cross-sectional shape, they can make steel more efficient and improve the bearing capacity. Unlike ordinary I-shaped steel, the flange of the H-shaped steel is widened, and the inner and outer surfaces are usually parallel, which makes it easy to connect with other components with high-strength bolts. Its size structure series is reasonable, and the models are complete, which is convenient for design and selection.
The flanges of H-shaped steel are of equal thickness, with rolled sections and combined sections composed of three plates welded together. I-shaped steel is a rolled section. Due to poor production technology, the inner edge of the flange has a slope of 1:10. The rolling of H-shaped steel is different from that of ordinary I-shaped steel, which only uses one set of horizontal rollers. Because its flange is wide and has no slope (or the slope is very small), it is necessary to add a set of vertical rollers for rolling at the same time. Therefore, its rolling process and equipment are more complicated than ordinary rolling mills. The maximum height of rolled H-shaped steel that can be produced in China is 800mm. If it exceeds this, it can only be a welded combined section. My country’s national standard for hot-rolled H-shaped steel (GB/T11263-1998) divides H-shaped steel into three categories: narrow flange, wide flange, and steel pile, with the codes hz, hk, and hu respectively. Narrow flange H-beams are suitable for beams or compression-bending members, while wide flange H-beams and H-beam piles are suitable for axial compression members or compression-bending members. Compared with H-beams, W, IX, and IY are not as good as H-beams under the same weight.
Post time: Jan-22-2025