Light steel system building has become the focus of the development of industrial green building because of its light weight, good structural strength, wide applicability and mature industrial technology system.

The light steel structure not only has the same advantages as the precast concrete structure, such as short construction period, high material utilization rate, low personnel investment and low engineering cost, but also has unique advantages in building energy saving and emission reduction performance because of its improved waterproof, thermal insulation, thermal insulation and other structural treatment methods. Light steel structure combines industrial construction technology with green building technology to achieve the goal of improving the quality of building use and reducing the level of building energy consumption.

obvious advantages

The construction technology of light steel system originated from abroad. With the advantages of light weight, high strength, easy production and processing, good durability and recyclable materials, it has developed rapidly abroad. In 1965, light steel system buildings in the United States accounted for 15% of the construction market in the United States, reaching 75% by 2000. The development of light steel structure system buildings in Japan began in 1950. By 1995, light steel structure prefabricated houses accounted for about 80% of all prefabricated houses in Japan. Europe proposed three light steel structure residential modes of assembly, unit and hybrid in 1970. In 1993, the European Committee for Standardization and the European Steel Structure Association jointly issued a unified standard for the use of light steel structures in Europe.

"Due to the limited research on steel production capacity and related construction technology and other factors, it was not until about 2000 that light steel system buildings began to rise. China's light steel system construction technology and related standards, norms learn from the experience of developed countries, many foreign light steel system construction technology and products into China, promote the development of China's light steel system construction. At the same time, in order to resolve the national steel overcapacity and realize the transformation of the construction industry, the government has issued a number of policies to encourage the development of light steel system buildings. For example, in 2015, the Ministry of housing and urban rural development and the Ministry of industry and information technology issued the action plan for promoting the production and application of green building materials, and in 2016, the State Council issued some opinions on Further Strengthening the management of urban planning and construction." Cui Yuansheng, chief expert of the Institute of Technical Information of the Building Materials Industry, said.

According to relevant experts, the domestic practice of light steel system architectural design and construction can be roughly divided into two categories: one is that the scientific research team of colleges and universities carries out the research and development of steel structure system construction technology with the support of scientific research projects; the other is that building materials and engineering enterprises introduce or independently develop light steel system construction technology, but due to the low acceptance of the domestic market, Enterprises currently mainly serve foreign markets.

Puzzle to be solved

China's light steel system construction started late, due to the lack of research process, the current construction practice in this area is still in the demonstration test stage. Cui Yuansheng said that there are still some problems in China's light steel system construction. First, copying foreign light steel system construction technology is not applicable in China. Due to the lack of architectural design guidelines for light steel system buildings, in the practice of building engineering based on the structure and construction level, the differences in climate in China and the different performance and quality of the production of building materials are often ignored, and the completed projects are prone to defects in thermal insulation, moisture-proof performance, durability and so on.

Second, the promotion is concentrated in the northern heating area. The problem of heating energy consumption in northern China is serious. In order to reduce the heating demand, the research on energy saving and emission reduction technology tends to the northern region, and the research on hot summer and cold winter zone and hot summer and warm winter zone needs to be carried out. China has a vast territory and large climate differences in various regions, and light steel system buildings should carry out technical research according to local conditions.

Three is the lack of light steel system of passive housing technology integration research. Light steel system building is an important direction of China's construction industrialization. With the increasing requirements of building quality and energy conservation and environmental protection, the demand for its integration with passive house technology will also increase.

Fourth, there is no national light steel industry chain cluster, industrial integration production is scattered, can not form an effective cluster effect.

Fifth, the light steel system building needs the integrated design and construction of the whole house, and the combination of design and construction can reduce the cost. In order to give full play to the advantages of light steel building, the integrated design and construction of prefabricated building must be realized as soon as possible.

extensive application

Because of its many advantages, in recent years, some energy-saving and environmental protection technologies in the light steel building system have entered the modern construction market in China, and the application effect is good.

Prefabricated exterior wall enclosure system. According to Zhang Jianwei, president of the design institute of China passive integrated building materials industry alliance, an external insulation system can be formed by adding a thermal insulation material to the filling layer of the exterior wall of the building near the outdoor side. The external insulation system has obvious advantages over the traditional internal insulation system in the area of indoor space, the practicability of indoor space and the avoidance of structural deformation due to temperature changes. Cold-formed thin-walled steel outer structure through the use of external composite insulation, according to the need to use multi-layer insulation site splicing, or in the factory prefabricated into external composite insulation board, according to different climate areas using different insulation board combination.

Light steel insulation composite integrated assembly wall. The system is also called sheet metal wall structure, is light steel keel structure and thermal insulation material after autoclaving, machine processing press into a whole, with the formation of sheet metal combined into a box structure, the thickness can be adjusted according to the climate area. The structure has no cold and hot bridge design, thermal insulation, seismic, wind resistance performance is good, horizontal, longitudinal load and shear load is high, with light steel profiles instead of traditional materials, can achieve the purpose of energy saving and environmental protection.

Light steel panel wall structure housing components can all be large-scale production in the factory, the site only needs assembly operations, to achieve the factory prefabrication of components and the site assembly construction of the house, is currently a more mature integrated housing system, but also the future direction of the development of assembly building.