Steel structure building is a new type of building system, with light weight, easy installation, short construction cycle, good seismic performance, fast investment recovery, less environmental pollution and other advantages, so it is widely favored by all parties in the industry. Under the influence of policies such as advocating green building, energy conservation and environmental protection, and resource recycling, steel structure is gradually widely used in the construction of prefabricated buildings, and the scale of steel structure industry continues to expand.
In 2021 of the eighth national passive assembly construction peak BBS (BBS), the building materials industry technology intelligence research institute chief expert Cui Yuan said, although compared with the developed abroad, steel structure building in our country application level is relatively low, but foreign prefabricated construction experience, the development and domestic policy influence, It can be predicted that the steel structure industry will get a rapid development, steel structure building or will become the mainstream choice for the construction of prefabricated buildings.
The domestic steel structure industry develops rapidly
According to the structural system of prefabricated buildings, prefabricated buildings can be divided into precast concrete structure, steel structure and wood structure. Among them, the steel structure is composed of steel beams, steel columns, steel trusses and other components supported by shaped steel and steel plates. Each component or component is usually connected by weld, bolt or rivet. At the same time, silanization, pure manganese phosphating, washing and drying, galvanized and other rust removal and anti-rust processes are adopted.
Reporters learned from the forum, steel structure compared with the traditional concrete building, steel plate or steel replaced reinforced concrete, higher strength, better earthquake resistance. And because the components can be factory made, installed in the construction site, can greatly shorten the construction period. Due to the reuse of steel, it can reduce the production of construction waste, more green environmental protection, so it is widely used in industrial buildings and civil buildings.
According to the relevant data, at present, the domestic steel structure industry presents a rapid development trend, steel structure output increased from 8.5 million tons in 2002 to 22.94 million tons in 2009, the annual compound growth rate reached 15.24%. From 2010 to 2019, the steel structure developed rapidly, with the steel structure production increasing from 26 million tons to 73.73 million tons.
Due to the advantages of high strength, light dead weight, good overall rigidity and strong deformation ability, steel structure is especially suitable for the construction of large span, super high, super heavy buildings, which is expected to become the mainstream structure of prefabricated buildings in the future.
The development level of steel structure industry needs to be improved
Although the overall development speed of steel structure in our country is relatively rapid, there is a certain margin compared with the development level of the developed steel structure architecture in the United States and Japan. Cui Yuan sound in the path of passive low energy consumption building materials industry development in China, "the report, according to data from the United States, Japan and other developed industrial steel used accounts for 50% of the proportion of the steel production, accounting for over 50% of the total consumption of steel, steel structure steel volume accounts for more than 30% of steel production, steel structure building area accounted for more than a total construction area of about 40%; And at present, the amount of steel used in construction accounts for about 20% of steel production, 22% to 26% of the total amount of steel consumption, steel structure with steel production proportion is less than 2%, steel structure construction area proportion of the total construction area is less than 5%. Thus, the application level of steel structure in China has to be improved, but the development space is relatively large at the same time.
The overall concentration of domestic steel structure industry is low, which also restricts the development of the industry. It is understood that at present, the annual output of steel structure below 10,000 tons, 10,000 tons to 50,000 tons, 50,000 tons to 300,000 tons, 300,000 tons and more than the number of steel structure enterprises are 4000 to 5000, 100, 20, 6 to 8. In the industry, there are only 51 enterprises with the special manufacturing qualification of steel structure, and even fewer enterprises with both the qualification and the first-class qualification of professional contracting. Mergers and acquisitions or the necessary means to promote the high-quality development of the industry.
In addition, related experts said that the domestic construction industry has a wealth of reinforced concrete structure construction experience, but the steel structure design and construction of the basic experience is quite lack. Therefore, forming steel structure construction experience, improving the accuracy and speed of steel structure construction, solving fire prevention and anti-corrosion problems, and using emerging technologies such as BIM have become urgent problems to be solved in the steel structure industry.
Steel structure building application space is broad
In order to improve the industrialization level of building construction, improve the proportion of parts, and promote the low-carbon and energy-saving development of the building industry, the domestic construction industry has begun to study the application of steel structure in all kinds of buildings, committed to expanding its application scope, so as to make the building more green and environmental protection. After European and American experts' research on the durability, practicality and economy of metal structure buildings, it is shown that steel structure meets the conditions of green building, that is, it is conducive to protecting the environment and saving energy.
It is understood that prefabricated buildings will account for more than 20 percent of new buildings by 2020 and more than 50 percent of new buildings by 2025, according to the Outline of Modernization Development of the construction industry released by the Ministry of Housing and Urban-Rural Development. As the application structure of green building, steel structure can meet most of the needs. But as a larger building volume and greater steel production in the world, the application level of steel structure buildings is obviously lagging behind. At present, the proportion of domestic steel structure buildings accounted for less than 10% of the construction market. From the policy guidance and the present situation of the application of steel structure in our country, there is still a lot of room for development of steel structure building
"From the perspective of the country's social development, the rapid growth of population and the acceleration of urbanization process in the next 30 years also provide broad space for the development of steel structure buildings," Cui said. The production efficiency of traditional buildings is low, which causes serious damage to the environment and brings great negative influence to the economic development. Therefore, in the new round of building construction, energy-saving and land saving green environmental protection steel structure buildings will face new development opportunities. According to relevant institutions, the market size of China's residential steel structure is expected to exceed 300 billion yuan around 2022, and the development prospect is worth looking forward to."
In recent years, landmark buildings built with steel structure have been appearing continuously due to the obvious advantages in environmental protection, energy saving, high efficiency and factory production compared with brick and concrete structures. For example, the swimming center in Beijing (Water Cube), the Jinmao Tower in Pudong, Shanghai (421 meters), and the Diwang Tower in Shenzhen (325 meters). Based on this, some industry experts believe that the 21st century is the era of metal structure, and steel structure may become the mainstream of the new construction era.
