Why does the central government advocate the promotion of prefabricated buildings, steel structures and modern wood structures this time?

● "China's research and development of prefabricated houses began at 1959. ● In the 1960s and 1970s, referring to the experience of the former Soviet Union and Eastern European countries, prefabricated houses flourished. ● By the end of 1970s, the proportion of prefabricated buildings in Beijing reached 30% and that in Shanghai reached 50%. By the end of 1980s, the prefabricated houses had shrunk dramatically and dropped out of people's sight. There are many problems in the use function and structural safety of large board houses in the 1960s and 1970s. At the same time, due to the imperfect urban transportation network, cheap migrant workers have replaced industrial workers, and the economy and assembly advantages of industrialized houses have not been reflected. ● Therefore, by the end of 1980s, the field of housing construction had shrunk dramatically, and there would be no further development in the next 20 years. " My understanding of the problem here is that light steel houses need workers with certain skills, and now migrant workers are too cheap. In order to reduce costs, builders can only choose concrete structures with low technical threshold. ●2065 438+0 1 year, the steel output of China reached a record high, reaching 627 million tons. Today, with the unprecedented pressure of energy saving and emission reduction, advocating low-carbon economy and sustainable development, steel residential buildings have attracted wide attention from all walks of life. Features and advantages of steel structure residence ● Greatly reduce water consumption and sewage discharge. If its market share increases by 5 percentage points, it will reduce the sewage discharge equivalent to 10 West Lake. ● Energy-saving (energy-saving in operation): CCA lightweight grouting wall has good self-insulation function, which is three times that of traditional brick wall and greatly reduces the energy consumption in operation. Land conservation (land improvement) ...