1.
The bottom of the laminated plate is mechanically made in the factory, which is smooth and high in strength.
Component storage and management fee: after component prefabrication and production, a large area of stacking yard is required for storage and management, which is not available in the traditional cast-in-situ construction method.
Reasons for the increment of prefabricated construction: the on-site construction of prefabricated buildings mainly involves the hoisting of prefabricated components.
4.
Material cost: compared with the traditional cast-in-situ mode, the on-site loss of material consumption is reduced and the material is saved.
4.
The fabricated structure is mainly produced in batch in the prefabrication plant, and the reinforcement binding and blanking are carried out in the factory, with concentrated human and material resources and high safety factor; 2.
The laminated plate is hoisted directly without formwork; 2.
Reinforcement needs to be bound and cut on site, which is very cumbersome, there are many workers and tools, and it is inconvenient to carry up and down the building; 2.
The measure cost of on-site construction of prefabricated buildings is basically the same as that of traditional buildings, and the use cost of on-site formwork and scaffold will be reduced.
Due to the high strength of the laminated plate itself, less materials are used for bottom support, less labor and materials; 3.
Reasons for the increase of component transportation cost: the transportation cost of prefabricated components refers to various expenses incurred in the process of transporting prefabricated components from the factory to the construction site.
If the component supply chain is perfect, the production demand of the prefabrication plant is strong, and the scale effect is obvious, the unit cost of the depreciation of fixed assets amortized into the component will be lower, which will lower the component price; On the contrary, it will push up the component price.
However, this may increase the transportation distance, increase highway charges and vehicle fuel charges, and increase the transportation cost.
The formwork adopts steel membrane with high strength, which can be used for many times and produced in batch, greatly saving wood formwork resources; 3.
The binding of floor reinforcement is directly carried out on the formwork, which is easy to cause reinforcement displacement, resulting in insufficient bottom protective layer, resulting in rust return and reinforcement leakage, affecting the structural strength of the whole body.
Wood formwork is used for column formwork blanking, which has serious waste of resources, poor recycling performance, low strength, easy pulp wrapping, formwork expansion, difficult to control, and complex operation of workers; 3.
So, where is the growth of construction and installation cost of assembly? What is the crux? The cost increment of construction and installation of prefabricated buildings is mainly reflected in three aspects: component production, component transportation, component construction and installation.
The construction cost of prefabricated building site mainly consists of component installation cost, measure cost, etc.
The components are fixed on site with inclined support, with high strength, high-strength grouting material is used at the connection position of the components, the grouting integrity is firm, the reinforcement is connected with sleeve, and the grouting strength is high.
It needs secondary plastering and repair, and the formwork removal is laborious and laborious.
2.
This part of cost is one of the main sources of incremental cost of component production.
Reasons for the cost increment in the component production stage: the cost in the production stage of prefabricated components mainly includes: labor cost, material cost, mold cost, production line depreciation cost, component storage and management cost, water cost, electricity cost, etc.
Labor cost: due to the flow production of prefabricated components and parts in the factory, most of the work is replaced by mechanical equipment, and the labor cost is reduced compared with the traditional construction method.
4.
The splicing of formwork is not firm and easy to run slurry, but the floor slab bottom is not smooth, there are butt joints, the camber is not easy to control, and the concrete removal after formwork pouring is laborious and manual.
The upper part of the laminated plate is bound with reinforcement, and the concrete pouring has high one-time forming strength.
Compared with the traditional cast-in-situ construction mode, the construction characteristics of prefabricated buildings determine that the unit shift consumption of hoisting machinery is relatively high and the labor consumption is relatively small.
Today, I’d like to share a brief summary of the rise of construction and installation cost between assembly and traditional cast-in-place: the rising proportion of the cost of prefabricated buildings is related to the specific assembly design scheme, prefabrication rate and assembly rate, which can not be generalized, but the overall construction and installation cost is about 10-15% higher than that of traditional cast-in-place.
The labor consumption in the construction process of prefabricated building site is less, but the requirements for the professional and technical level of managers and constructors are relatively high, which increases the training cost of employees.
Among them, the use cost of machines and tools on the construction site is high, mainly because the assembly construction requires higher accuracy of hoisting machinery, and the use strength and number of shifts of this kind of hoisting machinery are higher than those of general tower crane turnover equipment in traditional buildings.
When concrete is poured on site, it needs to be sent to the site by commercial mixing station for pouring.
3.
Zhuao College | molds for various prefabricated components are so expensive that how many times can they be reused at most? Depreciation cost of production line: fixed assets such as workshop of component factory and production line machinery and equipment of production components are invested greatly in the early stage, and these fixed assets will be depreciated in a certain way (if it is lease, the rent will be included in the component production cost).
The following table takes a single-storey 1000m2 residential project as an example, construction comparison and comparison of traditional cast-in-situ wall column beam and fabricated wall column beam 1.1 comparison of advantages and disadvantages of process 1.
In addition, the low reuse rate of molds, the higher the mold cost.
It can be hoisted directly, saving labor and working procedures..
The concrete is solidified on site, and the strength cannot be guaranteed.
The transportation cost is mainly related to the distance and mode of transportation: for the freight of prefabricated components, please refer to our previous article: Zhuao college| How to determine the service radius of prefabricated building component manufacturers? For the transportation of prefabricated components, especially on important urban traffic trunk roads, not only the volume size of components, but also the time period of traffic congestion should be considered.
2.1 comparison of advantages and disadvantages of traditional cast-in-situ floor slab and laminated floor slab 2.1 comparison of advantages and disadvantages of process 1.
1.
The use of split bolts causes holes on the wall and it is difficult to block in the later stage; 4.
As for the high cost of molds and how to reduce the cost of producing molds, please refer to our previous articles: Zhuao College | a sharp tool for large-scale production of prefabricated buildings, and the weight of molds accounts for 26%! Zhuao College | let’s look at some new things.
2.2 compared with the amount of manpower, scaffold erection 20, formwork installation 20, reinforcement binding 20, concrete pouring worker 10 and formwork removal 10; There are 80 people in total, 10 at the bottom support, 15 for lifting laminated plates, 12 for binding reinforcement and 10 for concrete pouring; There are 47 people in total.
The windowsill floor slab is supported by wood formwork, which uses too much formwork materials, large labor consumption and too much material transportation; 2.
1.2 the manpower is compared with 30 reinforcement workers, 3 signal workers, 10 reinforcement blanking workers, 10 formwork workers, 10 formwork blanking workers, 10 concrete pouring workers and 10 formwork removal; 73 people in total, 15 on-site hoisting, 3 signal workers, 10 inclined support installation, 5 grouting, 2 reinforcement workers at the cast-in-situ position, 2 formwork and 3 concrete cast-in-situ; There are 40 people in total.
Do not use split bolts and do not need to be blocked later.
Mold cost: at present, the standardization of part design has not been fully realized.
Prefabricated component factories are generally located in the suburbs far away from the city, with low land cost and close to the sand and stone mining land.
Compared with the advantages and disadvantages of the traditional cast-in-situ stairs and prefabricated stairs, 3.1 compared with the advantages and disadvantages of the traditional stairs, the formwork erection on the site is complex, the formwork strength is not easy to control, and the finished product quality is not easy to control after pouring concrete.
The fabricated structural ladder is made of steel membrane in the factory, with excellent strength and appearance.
More scaffolds are required for the support and reinforcement at the bottom of the formwork to ensure the stability of the wooden formwork; More labor is used to erect and transport scaffolds.
The more kinds of prefabricated components are produced, the more complex the structure is, the more molds need to be used.
3D printing molds for prefabricated components.
The component installation cost at the construction site of prefabricated buildings mainly includes: component vertical transportation cost, installation labor cost, machine use cost, etc.
3.
1.
There are a large number of workers and long time interval, which is easy to produce construction cold joints.