by 〔 Abstract 〕 The construction period of the housing industrialization base is long, and the one-time investment cost is large.
For the regions where the development of the housing industrialization is relatively lagging behind, the PC component mode of the industrialization base production is greatly limited in the third and fourth tier cities.
The above problems can be solved by adopting nomadic production mode to produce and construct prefabricated components, which can also reduce the transportation cost and complete the production task of prefabricated components with the best economic benefit and the minimum equipment cost.
The production advantages and management requirements, production planning, deepening of production content of nomadic prefabricated components are described in detail, and production cases are introduced.
1.
Production advantages and management requirements of nomadic prefabricated components 1) For areas where the local government requires that prefabricated components must be used for construction, the cost of self production of prefabricated components by nomadic production is lower than that of external purchase.
The progress of nomadic production prefabricated components can be adjusted according to the site, which is more suitable for high turnover projects.
2) For the third and fourth tier cities where the local government requires the use of prefabricated buildings, the nomadic production of prefabricated components can solve the problems of insufficient supply of external procurement and high transportation costs.
3) In the current market situation, the nomadic production mode has a flexible layout and low one-time input cost requirements for the component production base, which is more suitable for the market demand of prefabricated buildings in the transition period.
4) The production of nomadic prefabricated components shall have the production process facilities and test and detection conditions to ensure the product quality requirements, and a sound quality management system and system as well as a traceable information management system shall be established.
Before production, the design, production and construction units shall be organized to conduct design document disclosure and joint review.
If necessary, the processing details shall be prepared according to the approved design documents, proposed production process, transportation scheme, hoisting scheme, etc.
Production plan shall be prepared, which should include production plan and process, mold plan and plan, technical quality control measures, finished product storage, transportation and protection plan, etc.
2.
Nomadic production planning of prefabricated components 2.1 Disassembly and design requirements 2.1.1 Disassembly principle 1) The disassembly of components does not affect the safety of the structure, and does not affect the safety of the whole structure after the disassembly and installation of components.
The location of disassembly is convenient for anchoring, without potential safety and quality hazards.
2) The on-site construction is convenient.
After the prefabricated components are disassembled, the construction of the cast-in-place structure is more convenient, the prefabricated components are easy to be hoisted, and the anchoring part is easy to operate.
3) The hoisting quality of prefabricated components is moderate, and the hoisting cost of tower crane will not be increased.
The quality of prefabricated components meets the hoisting requirements of tower crane at this location.
The model of tower crane will not be adjusted, and the hoisting cost will not be increased.
4) The size of a single prefabricated component shall not be too large for easy transportation.
It shall be convenient to use general transportation vehicles to reduce transportation costs.
2.1.2 Design requirements 1) Types of prefabricated components planned for the project.
2) Prefabricated component plan split location.
3) The maximum lifting capacity of each disassembled component shall be determined according to the position relationship between each component and the tower crane in the general layout and the tower crane model.
The design shall determine whether core pulling measures are taken for prefabricated components based on lifting capacity.
2.2 Selection of on-site prefabrication and outsourcing of components Due to many types of prefabricated components and different characteristics of various prefabricated components, not all prefabricated components are feasible and economical to prefabricate on site.
According to the characteristics of all prefabricated components on site, they shall be selected differently.
2.2.1 Selection of on-site prefabricated type (see Figure 1) 1) Simple components with strong universality and large number can be used for all buildings, and simple components with large number of prefabricated components of this type for each unit shall be prefabricated on site.
The prefabrication of such components is difficult and the quality is controllable.
The on-site prefabrication can save costs, such as prefabricated balcony, prefabricated air conditioning panel, prefabricated bay window, etc.
2) The number of single buildings is small, but the common components of each building and project can be determined according to the on-site progress and demand.
The mold can be used in multiple projects with low cost, such as prefabricated stairs, prefabricated fire partition boards, etc.
2.2.2 The type of prefabricated components that can be purchased can be considered.
Due to the specific situation of the project, some special-shaped components appear, and the overall number is small and the various projects cannot be used universally.
In this case, outsourcing can be considered.
The on-site prefabrication of this type of special-shaped component is difficult, and the quality is difficult to control, the universality is poor, the mold can not be recycled, and the on-site prefabrication cost is high.
2.3 Planning of nomadic production site 2.3.1 Determining the area of nomadic production site (P) is related to the following related factors: the plane projection area (P1) of the same batch of prefabricated components, the area of component production site (P2), and the area of component stacking site (P3).
1) The plane projection area (P1) of the same batch of prefabricated components is generally the maximum plane projection area of all prefabricated components in a standard floor of all buildings under synchronous construction.
The projected area of each component plane is: the projected area of the prefabricated stair plane, that is, the area when the stair is placed parallel to the ground; Plane projection area of all wallboards, i.e.
floor area of wallboards laid flat on the ground; The plane projection area of the bay window is the floor area where the facade of the bay window is laid flat on the ground.
2) Component production site area (P2) The production site area required for the production of the same batch of prefabricated components includes the placement area and reinforcement processing area.
3) The component stacking area (P3) is used for stacking the prefabricated components that have been processed.
Under the condition that the flow construction does not consider the stock on site, the area of the component stacking site (P3) is equal to the area of the component production site (P2), which is also twice the plane projection area (P1) of the same batch of prefabricated components.
The area of the whole nomadic production site (P)=the floor area of the component production site (P2)+the area of the component stacking site (P3) × 1.25 (reduction coefficient of roads in the site)..
