Steel structure building is a new type of building system, which has the advantages of light weight, easy installation, short construction period, good seismic performance, fast investment recovery, and low environmental pollution. Therefore, it is generally favored by all parties in the industry. Under the influence of national policies such as green building, energy conservation and environmental protection, and resource recycling, steel structures have gradually been widely used in the construction of prefabricated buildings, and the scale of the steel structure industry has been expanding.

At the 2021 Eighth China Passive Assembly Building Summit Forum (hereinafter referred to as the forum) held a few days ago, Cui Yuansheng, chief expert of the Building Materials Industry Technology Information Institute, said that although compared with foreign developed countries, the level of application of steel structures in my country is relatively low. , But learning from the development experience of foreign prefabricated buildings, coupled with the influence of domestic policies, it can be foreseen that the steel structure industry will develop rapidly, and steel structure buildings may become the mainstream choice for constructing prefabricated buildings.

According to the prefabricated building structure system, the prefabricated building can be divided into precast concrete structure, steel structure and wood structure. Among them, the steel structure is composed of beam steel, steel column, steel truss and other components supported by section steel and steel plate. Each component or component is usually connected by welds, bolts or rivets. At the same time, silanization and pure manganese phosphating are used. , Washing, drying, galvanizing and other rust-removing and anti-rust processes.

It was learned from the forum that compared to traditional concrete buildings, steel structure buildings have replaced reinforced concrete with steel plates or section steels, which have higher strength and better seismic resistance. And because the components can be manufactured in factories and installed on the construction site, the construction period can be greatly shortened. Due to the reuse of steel, construction waste can be reduced, and it is more environmentally friendly, so it is widely used in industrial and civil buildings.

According to relevant data, at present, the domestic steel structure industry is showing a rapid development trend. The output of steel structure increased from 8.5 million tons in 2002 to 22.94 million tons in 2009, with an average annual compound growth rate of 15.24%. From 2010 to 2019, it was the stage of rapid development of steel structure, and the output of steel structure increased from 26 million tons to 73.73 million tons.

Because steel structure has the advantages of high strength, light weight, good overall rigidity, and strong deformability, it is especially suitable for the construction of large-span, super-high and super-heavy buildings, and it is expected to become the mainstream structure of prefabricated buildings in the future.

The development level of the steel structure industry needs to be improved

Although the overall development speed of my country's steel structure industry is relatively fast, there is still a certain gap compared with the development level of steel structure buildings in developed countries such as the United States and Japan. Cui Yuansheng's data in the "Research on the Development Path of my country's Passive Ultra-low Energy Building Materials Industry" shows that the current industrial developed countries such as the United States, Japan and other industrialized countries account for 50% of the country's steel output and 50% of the total steel consumption. Above, the amount of steel used in steel structures accounts for more than 30% of steel output, and the area of steel structures accounts for more than 40% of the total building area; and the current amount of steel used in construction in my country accounts for about 20% of the national steel output, accounting for the total steel consumption. From 22% to 26%, the amount of steel used in steel structures accounts for less than 2% of the country’s steel output, and the area of steel structures accounts for less than 5% of the total construction area. It can be seen that the application level of steel structure buildings in my country needs to be improved, but at the same time the development space is relatively large.

The overall concentration of the domestic steel structure industry is relatively low, which also restricts the development of the industry. It is understood that at present, the number of steel structure enterprises with an annual output of less than 10,000 tons, 10,000 to 50,000 tons, 50,000 to 300,000 tons, and more than 300,000 tons are 4,000 to 5,000, 100, 20, 6 to 8. There are only 51 companies in the industry that have special steel structure manufacturing qualifications, and even fewer companies have both this qualification and the first-level qualification for professional contracting. Mergers and acquisitions are necessary means to promote the high-quality development of the industry.

In addition, relevant experts said that the domestic construction industry has a wealth of experience in the construction of reinforced concrete structures, but the basic experience in the design and construction of steel structures is quite scarce. Therefore, forming experience in steel structure construction, improving the accuracy and speed of steel structure construction, solving fire protection and anti-corrosion problems, and using emerging technologies such as BIM have become an urgent problem in the steel structure industry.

Broad application space for steel structure buildings

In order to improve the industrialization level of building construction, increase the productization rate, and promote the low-carbon and energy-saving development of the construction industry, the domestic construction industry has begun to study the application of steel structures in various buildings, and is committed to expanding its application scope and making buildings more green and environmentally friendly. European and American experts have studied the durability, practicability, and economy of metal structure buildings, and it is shown that steel structures meet the conditions of green buildings, that is, buildings that are conducive to environmental protection and energy saving.

It is understood that previously, the "Outline for the Modernization of the Construction Industry" issued by the Ministry of Housing and Urban-Rural Development stated that by 2020, prefabricated buildings will account for more than 20% of new buildings, and by 2025, prefabricated buildings will account for more than 50% of new buildings. . As the application structure of green buildings, steel structure buildings can meet most of the needs. However, as the country with the largest building volume and steel output in the world, my country's application level of steel structure buildings is obviously lagging behind. At present, domestic steel structure buildings account for less than 10% of the construction market. From the perspective of my country's policy orientation and the application status of the steel structure industry, steel structure construction still has a lot of room for development in my country.

Cui Yuansheng said: "From the perspective of global social development, especially in developing countries, the rapid population growth and the acceleration of urbanization in the next 30 years will also provide a broad space for the development of steel structure buildings. The production of traditional buildings. Low efficiency, serious damage to the environment, and a greater negative impact on economic development. Therefore, in the new round of building construction, energy-saving and land-saving green and environmentally-friendly steel structure buildings will face new development opportunities. According to relevant agencies’ estimates, The market scale of China's residential steel structure is expected to exceed 300 billion yuan around 2022, and the development prospects are worth looking forward to."

In recent years, because steel structure buildings have obvious advantages in environmental protection, energy saving, high efficiency, and factory production compared with brick-concrete structures, landmark buildings constructed with steel structures have continued to appear. For example, the National Aquatics Center (Water Cube) in Beijing, the Jin Mao Tower in Pudong, Shanghai (421 meters), and the Diwang Tower (325 meters) in Shenzhen, etc. According to this, some industry experts believe that the 21st century is the era of metal structures. Steel structure may become the mainstream of the new construction era.