by Recently, the 14th five year plan for the development of construction industry issued by the Ministry of housing and urban rural development made it clear that during the 14th Five Year Plan period, China should initially form a high-quality development system framework for the construction industry, improve the operation mechanism of the construction market, basically improve the project quality and safety guarantee system, and greatly improve the level of industrialization, digitization and intellectualization of buildings, The green transformation of construction mode has achieved remarkable results and accelerated the transformation of the construction industry from large to strong.
There are two striking aspects.
One is to vigorously develop precast buildings.
Build a standardized design and production system for precast buildings, promote the intelligent upgrading of production and construction, expand the use scale of standardized components and parts, and improve the comprehensive benefits of precast buildings.
Improve the precast concrete building structure system applicable to different building types, and increase the integrated application of high-performance concrete, high-strength reinforcement, energy dissipation, shock absorption and prestress technology.
The policy system and industrial system for the coordinated development of intelligent construction and new building industrialization have been basically established.
Precast buildings account for more than 30% of new buildings, creating a number of Internet platforms for the construction industry.
Ten years ago, when he was still a counselor in the Counselor’s office of Wuhan municipal government, he went to Changchun and Changsha to investigate precast buildings.
Precast architecture began to attract people’s interest in the early 20th century and finally realized in the 1960s.
Britain, France, the Soviet Union and other countries first tried.
Due to the fast construction speed and low production cost of precast buildings, they are rapidly popularized all over the world.
Precast building refers to a building that transfers a large number of on-site operations in the traditional construction method to the factory, processes and manufactures building components and accessories (such as floor slab, wallboard, staircase, balcony, etc.) in the factory, transports them to the construction site, and assembles and installs them on site through reliable connection.
Advantages of precast buildings: 1.
High efficiency: compared with traditional methods, factory production is not affected by bad weather and other natural environment, the construction period is more controllable, and the production efficiency is much higher than manual operation.
2.
After standing for eight hours in a sealed environment with constant temperature and humidity, a standard PC board is formed.
The whole process from the cloth to the curing kiln is automatically controlled by computer, and the time is no more than 5 minutes.
The production efficiency and quality are many times higher than that of human workers.
After that, the PC board will be transported to the construction site together with many other parts precast in the factory and assembled into a house.
Moreover, such a “assembled” house can be “roadshow” through computer software in advance, and the actual on-site operation time can be saved by 70%, and the comprehensive time cost is only 1 / 3 of the traditional construction method.
Taking a 30 storey fine decoration residence as an example, the precast construction technology can be completed in more than 10 months from commencement to delivery, while the traditional construction method takes at least two or three years.
2.
High precision: the error of cast construction reaches millimeter level.
From the four assembled residential projects developed by Vanke, including sijihua City, golden mileage, Chenghua new garden and Qinglin path, nearly 1800 houses are involved.
Since the delivery in January 2010, the frequency of maintenance is very low, and only one case has a little leakage on the outer wall.
The reason is that it is integrated with precast building components and industrialized production, and the quality is more controllable.
It is said that the pull-out strength of its wall tiles is about 9 times higher than that of the traditional method.
3.
High quality: factory production of components, greatly improving the quality.
4.
It can greatly reduce manual dependence.
5.
Dry on-site assembly, saving water, electricity, materials and environmental protection.
Unified manufacturing in the factory can achieve maximum energy saving, land saving, water saving and material saving in the whole life cycle of the building.
According to the calculation of Shanghai pilot precast housing project, the production and construction process of precast buildings can save energy by about 50%, water by about 60%, materials by about 20%, land by about 20%, and reduce construction waste by about 80%.
Moreover, in terms of construction benefits, it can also be increased by 4-5 times.
6.
Have a relatively complete standard design system.
7.
The structure has good seismic performance.
8.
The building area can be increased.
Disadvantages of precast buildings: 1.
Increased cost: the cost of traditional construction projects is much cheaper than that of precast construction projects.
2.
Increased freight: components are directly transported to the construction site by the factory.
If the distance between the factory and the construction site is too far, the transportation cost of transporting components will increase.
3.
Size limitation: due to the inconsistent size of components, it is easy to restrict the production equipment, so it will be difficult to copy the larger components during reproduction.
4.
Small application fields: Although precast buildings have been vigorously promoted by the state, at present, the total height and storey height of precast buildings are greatly limited.
On November 14, 2015, the Ministry of housing and urban rural development issued the outline for the modernization development of the construction industry.
It is planned that precast buildings will account for more than 20% of new buildings by 2020 and more than 50% of new buildings by 2025.
On February 22, 2016, the State Council issued the guidance on vigorously developing precast buildings, which requires that precast buildings such as precast concrete structure, steel structure and modern wood structure should be developed according to local conditions, and strive to make the proportion of precast buildings in the area of new buildings reach 30% in about 10 years.
5.
Poor seismic resistance: due to the weak integrity and stiffness of precast buildings, the seismic impact capacity of precast buildings is poor.
Second, we should form a number of landmark products of construction robots and cultivate a number of intelligent construction and assembly construction industrial bases.
Strengthen the research on the core technologies of construction robots such as new sensing, intelligent control and optimization, multi machine cooperation and man-machine cooperation, study and prepare key technical standards, and form a batch of landmark products of construction robots..
