When Before China's construction industry is in the stage of transformation and upgrading, under the background of policy led, prefabricated design has become the inevitable trend of architectural development, so how to grasp the opportunity to realize the docking and integration with traditional design?
At 20:00 on June 28, Jiang Xuliang, head of assembly design department of Tianyou, analyzed the influence of prefabricated design on traditional design from multiple dimensions such as policy, concept and development trend in tenio online classroom.
The assembly design department carefully collates and summarizes the live broadcast content, and shares it with real estate customers and peers in the industry to jointly help accelerate the development of assembly design.
The influence of assembly design on traditional design
Head of assembly design department
Assembly policy and reward
Premier Li Keqiang mentioned in his government report at the fourth session of the 12th National People's Congress on March 5, 2016 "Vigorously develop steel structure and fabricated building".
In September of the same year, the State Council promulgated several opinions on Further Strengthening the management of urban planning and construction, which mentioned that "we should strive to make the prefabricated buildings account for 30% of the new buildings in about 10 years".
Under the guidance of national policies, At present, 31 provinces, autonomous regions and cities in China have formulated the development plan of prefabricated buildings.
(policy differences of typical cities in South and North China)
twenty twenty From the year of 2025, all provinces and cities in China will enter a period of comprehensive development, Compared with northern cities, the development of prefabricated buildings in southern cities is earlier, the upstream and downstream industrial chain is more complete, and the development of technology and technology is more mature.
The government of southern cities has more perfect incentive policies for the implementation of assembly type, such as financial subsidies, plot ratio incentives, tax incentives and other aspects, But at the same time, it also reflects that the development space of prefabricated buildings in northern China is larger.
Prefabricated building concept
Prefabricated building refers to the building constructed by prefabricated components through reliable connection, which has two main characteristics
1. The main components of a building（ Especially structural members ）Prefabricated form is adopted.
2. The connection mode of prefabricated components must be reliable.
According to the definition of "evaluation standard for prefabricated buildings", prefabricated buildings are composed of“ Peripheral, system and system components The main parts of the four systems are integrated with prefabricated parts.
Prefabricated buildings in China are mainly composed of prefabricated concrete structure, fabricated steel structure and fabricated wood structure, In the newly started prefabricated buildings in 2019, prefabricated concrete structures account for 65% of the newly started prefabricated areas, Fabricated steel structure accounts for 30%, other structures account for 3.6%, and wood structure accounts for 0.6%.
It can be seen that prefabricated concrete structure will still be the main prefabricated building form in China for some time to come, Steel structure building will be a kind of prefabricated building which will be vigorously promoted and developed in China in the future. The form of prefabricated wood structure building is affected by the actual situation of our country, and its development space is limited in the short term.
At present, prefabricated buildings have shown the following advantages in the mature stage of development:
1. Improve the quality of buildings, The prefabricated building design needs to be refined and collaborative, and the construction error is measured in mm, which can improve the building accuracy.
2. Saving labor and improving efficiency, The project with high degree of automation of production process can save more than 50% of labor force.
3. Energy saving, emission reduction, material saving, Reduce the consumption of formwork materials, leveling layer and plastering layer and construction waste.
4. Shorten the construction period, At the same time, the construction period of the traditional assembly design is less affected than that of the traditional cast-in-place construction technology.
In China, the advantages of prefabricated buildings have not been fully reflected. The specific reasons are as follows:
1. Maturity needs to be improved
2. The design precision needs to be improved
3. Professionals are relatively scarce
4. Uncontrollable cost increment
5. Reliability of connection node is questionable
Impact on traditional design
Combined with the development status of prefabricated building in China, we need to pay more attention to the influence of prefabricated design on traditional design.
From the design of all professional, to achieve the From the pre consideration of the construction scheme stage, the practical problems in the construction drawing stage, and the calculation content of the later production and installation Carry out macro control.
Prefabricated architecture advocates "Two responses and four adaptations" It should be fully decorated, integrated, pipeline separated, drainage on the same floor, large span and uniform Bay size.
In the scheme stage, the main consideration is the assembly rate The impact of each score on the scheme:
1. Whether sandwich panels are used for external walls should be considered in advance, If adopted, the external wall thickness will increase the thickness of the outer leaf plate by 50 mm ~ 60 mm, resulting in the increase of the external contour of the building and the decrease of the building spacing, so the plot ratio should be considered comprehensively.
2. The form of ground heating should be considered in advance, Whether indoor floor is elevated floor or direct laying dry floor heating, whether pipeline separation is adopted or not, has an impact on floor height and sunshine calculation.
3. Whether integrated kitchen and toilet and drainage on the same floor should be considered in advance, Integrated toilet adopts the same floor drainage, which can give full play to the advantages of integrated toilet.
In addition, there are three suggestions for building layout
1. The types of building types formed by unit type should be merged as far as possible.
2. The plane of the building should be regular.
3. The spacing of column net and bay size should be uniform.
There are two suggestions for building facade modeling
1. It is not appropriate to change the facade shape of prefabricated building too much, and the irregular change will greatly increase the cost.
2. Prefabricated components can be used in a regular way.
Construction drawing stage
Prefabricated building has higher requirements for coordination with construction drawings.
In this paper, the structure of the assembly system Shear wall residence For example, whether it is possible to reserve enough building walls and window openings for prefabrication when arranging structural shear walls, so as to achieve the purpose of not splitting the structural edge components.
At the same time, the prefabrication of building wall should be considered Influence on structural stiffness ， If the connection and structure are not reasonable, it will increase the overall stiffness of the structure, which will lead to the increase of seismic force.
In addition, there are building envelope systems, prefabricated exterior enclosure systems have become the mainstream practice in some areas. For example, the non bearing retaining wall is not masonry and the internal partition wall is not masonry, which brings about the change of building wall construction mode and structural load.
Suggestions for selecting modular design services
In view of the development trend of prefabricated building in China, the selection of appropriate prefabricated design service will determine the landing and economy of the whole prefabricated building project.
1. Identify the assembly design team in advance
Considering the characteristics of prefabricated building in the scheme stage can avoid the repeated quantities caused by adjustment in the construction drawing stage, so as to reduce the cost and shorten the construction period.
2. Select mature assembly design team
The mature assembly design team will fully consider the reasonable cost scheme, plot ratio incentive policy, prefabricated building prefabrication conditions in the early stage of design, so as to avoid the design risk.
In addition, mature project experience can be used to save cost and construction period for customers.
3. Commission a company to complete the layout and processing drawings
The layout plan (assembly split drawing) and detailed processing drawing of components are completed by one company, which can better reflect the continuity of assembly design and avoid the problems of inconsistent standards and poor communication caused by subsection entrustment.
4. Ability to use new design ideas (CSI)
CSI system will be the focus of the future development of prefabricated buildings, Design companies with CSI design capability will bring more premium prefabricated building products to customers.
5. Skilled application of Bim in project management
BIM is not just for design, It is an important tool of whole process management. The application of Bim in assembly design can improve efficiency, reduce drawing error rate, improve design, production and construction efficiency, and fully save construction period.
The national policy for the development of prefabricated construction industry continues to increase, industrial support At the same time, compared with the cast-in-place mode, the cost advantage of prefabricated building will gradually appear, and there is still a huge room for improvement in China's prefabricated building.
Tianyou assembly design department has a professional and mature team to provide assembly consulting and integrated design services, We will deeply study and solve the technical difficulties of assembly, optimize and improve the level of assembly design, and provide customers with the best quality service, Also contribute to the development of assembly industry!
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