Prefabricated Construction Process:
1 Deepening design of prefabricated components
Carry out in-depth design and construction verification, improve the detailed drawings of prefabricated components and the detailed drawings of construction and assembly, and avoid mistakes, omissions, collisions, and missing during component processing and construction; the corresponding reserved holes and embedded parts should be carefully checked before processing to avoid on-site chiseling.
2 Prefabricated component production
Prefabricated components usually include exterior wall panels, bay windows, balconies, stairs, air conditioning panels, composite panels, composite beams and columns, etc. Among them, PC exterior wall panel components, as non-structural components, are "outerwear" attached to the main structure, and are elastically connected to the main structure in a side-connected manner.
3 Transportation of prefabricated components
To prevent damage and overturning of components during transportation, a special fixed bracket for stable vehicle transportation is set. A full-length pad should be placed close to the lifting ring along the length of each composite board, and the upper and lower edges of the prefabricated board should be aligned, aligned, leveled, and padded. The stacking height is not more than 5 layers, and the stacking height of prefabricated stairs is not more than 2 layers. The lower part of the component is padded 100mm away from the vehicle body with wooden planks.
4 Acceptance of prefabricated components
After the components enter the site, they are inspected piece by piece, including appearance quality, geometric dimensions, embedded parts, reserved holes, etc. If they are found to be unqualified, they will be withdrawn from the site; the identification of prefabricated components is checked, including the number of the composite board, the simplified number of the hoisting, and the installation direction.
5 Storage of prefabricated components
When the construction site is laid out, the storage site of prefabricated components is considered, and the scope of the component storage site is marked out at the construction site. The site is leveled and hardened, marked with warning signs, and standardized management; the components are stacked according to model and specification, and two full-length pads are placed under each board. The pads are placed close to the lifting ring along the length of the composite board, and the upper and lower sides are aligned, aligned, leveled, and padded. Overlapping of boards of different specifications is not allowed. The stacking height is not more than 5 layers; the lower part of the component is padded 100mm from the ground with wooden planks; the staircase shelving stress point is the same as the lifting point of the beam.
6 Prefabricated component hoisting
Re-measure the elevation, position the line, then hoist the prefabricated components in place, calibrate and reinforce them.
7 PC main structure construction
After completing the hoisting acceptance of the prefabricated components and ensuring that the diagonal braces, footers, component connectors, etc. are stable, proceed to the next steel bar binding and mold closing process, pour the wall and floor concrete as soon as possible according to the construction period to form a structural whole, and record the installation time of each component.
Key points of quality control 1. Before the production of prefabricated components, the steel sleeve connection joints shall be inspected, including appearance quality, dimensional deviation, material report provided by the factory, joint type inspection report, etc., and the steel sleeve grouting connection joint specimens shall be made as required for verification tests; 2. Concealed engineering inspection shall be carried out on prestressed tendons and various embedded components; 3. The installation sequence, calibration positioning, and temporary fixing measures of prefabricated components are the key to the construction of prefabricated structures and should be strictly implemented according to the plan; 4. The post-cast concrete nodes of prefabricated structures are the key to ensuring the bearing capacity. The steel connection and anchorage at the nodes must be checked according to the design requirements. The support removal or superstructure installation can be carried out only after the test blocks under the same conditions at the nodes reach the design strength.
Prefabricated Component Production And Construction Process
1 Formwork assembly
Assemble and connect the steel formwork made according to the form of prefabricated components
2 Rebar binding
Bind the processed steel bars according to the form of components and weld them for reinforcement
3 Rebar placement
Put the steel bars into the formwork and fix them in place
4 Hidden inspection
Check the installation of prestressed steel bars, later parts, reserved holes, embedded parts, etc.
5 Concrete pouring
1. Pour concrete with a concrete feeder and compact it with a high-frequency vibrator; 2. Use a steel trowel and brush to trim the surface; 3. Use steam to heat and maintain the concrete.
6 Component identification
Measure the size and strength of the prefabricated components, and identify each component with an independent number according to the building, floor, and location.
Key Points Of Quality Control
1. The size of the steel mold must be accurately manufactured according to the size of various components;
2. The size of the prestressed tendons, embedded parts, and reserved holes must be accurately positioned according to the requirements of the drawings and installed and fixed firmly;
3. After the components are formed, they must be numbered independently according to the use requirements to avoid lifting errors.
Installation And Construction Technology Of Prefabricated Composite Panels
1 Preparation before hoisting
Check the elevation, axis, component displacement, support installation, embedded ring, and other settings.
2 Formwork support system erection
Establish the support system according to the requirements of the plan.
3 Installation and splicing
According to the displacement of the cast components, the precast concrete PC exterior wall panel can be used as the outer formwork of the shear wall and connected to the inner cast-in-place reinforced concrete structure.
4 Node connection
The node connection between the PC component and the cast-in-place structure is reinforced according to the requirements of the plan.
5 Hoisting of the composite slab
According to the control line, the composite slab is hoisted and put into place.
6 Inspection and acceptance before pouring
Perform hidden acceptance of steel bars, calibrate the components, and reinforce and correct the support connection.
7 Concrete pouring
After the precast wall panels are installed in place, pour the concrete of the wall columns first, then pour the concrete of the beams and slabs, and connect them to the main structure as a whole through the reserved steel bars on the PC slabs.
Key Points Of Quality Control
1. Strictly control the installation sequence, calibration positioning, and temporary fixing measures of prefabricated components according to the plan;
2. Strictly control the quality of sleeve grouting connection joints. During the inspection batch acceptance, if the joint quality is defective, a third-party independent testing agency can be entrusted to conduct non-destructive testing;
3. The inspection requirements for cast-in-place concrete of prefabricated structures shall be implemented by the current "Concrete Structure Engineering Construction Quality Acceptance Code";
4. Strictly control the waterproof construction quality of the exterior wall panel joints, and conduct a pressure water spray test for no less than 2 hours.
Prefabricated Stair Installation Construction Process
1 Marking lines
According to the drawings, the control lines are marked on the platform structure.
2 Leveling at the base support
At the connection of the prefabricated staircase, the horizontal joint is leveled with C30 fine stone concrete.
3 Preparation for hoisting
The prefabricated staircase is hoisted with the hoisting parts designed by the manufacturer and hoisted with a 2.5-ton duckbill hoist.
4 Determination of installation time
After the upper wall is demoulded, the lower prefabricated stair treads are hoisted to ensure the strength of the L-shaped beam.
5 Determination of hoisting angle
For ease of installation, the prefabricated staircase is hoisted at an angle slightly larger than the natural inclination angle of the stair tread (e.g., the natural inclination angle is 33°, and the inclination angle during hoisting is 34°~36°).
6 Hoisting of prefabricated stairs
The hoisting distribution beam and auxiliary hoisting equipment provided by the manufacturer are used for hoisting; the stairs are transported with long and short ropes to ensure that the state during hoisting is the same as the state after installation, and the stair beam is hoisted flat.
7 Positioning adjustment and welding
After the hoisting is completed, the correction is carried out; the vertical joints at the connection of the prefabricated stairs are filled with C30 fine stone concrete; the connection between the stairs and the upper end of the rest platform is welded with steel plates.
8 Staircase finished product protection
The stairs are the main vertical passages during the construction process. After the connection and fixation are completed, the template must be laid on the surface to protect the finished product.
Key Points Of Quality Control
1. The surface of the connection between the platform and the stairs must be flat, the component size must be accurate, and the embedded steel plate must be accurately positioned;
2. After the hoisting is completed, the stairs must be calibrated and the welding quality must be strictly controlled;
3. Use C30 fine stone concrete to fill the gaps and protect the finished product.
