It is not allowed to walk on the formwork platform coated with release agent; (3) The technical disclosure of concrete vibration shall be made to the workers, and the side standing of the vibration process shall be continued for a week.
During on-site lifting, obvious cracks are generated and prefabricated components are damaged..
The number of superimposed layers of pipelines at each location shall not exceed 2.
(2) Before lifting and transportation, members must be reinforced according to the design requirements.
(1) Reinforcing bars were set at the openings of doors and windows according to the requirements of the specifications.
2) Analysis on the causes of air holes and pits on the surface of prefabricated components (1) The use of grease type release agent leads to the formation of air holes in the greasy parts after concrete pouring (2) The formwork platform is not cleaned, and the convex parts on the surface of the formwork platform are easy to form after the application of release agent, and air holes are easy to form after concrete pouring and hardening (3) Measures for correcting the non dense concrete vibration (1) The use of water-based release agent or oil-based release agent to replace oil; (2) Before painting the release agent, the formwork platform must be cleaned, and the steel bar binding and embedding process shall use springboard.
Assembly and construction part 1) The prefabricated components arrive at the site for acceptance and stacking.
When the prefabricated components are stacked, first, the stacking site must be relatively flat.
(3) The laminated beam shall be hoisted according to the layered flow chart.
Factory production part 1) Analysis of embedded position deviation and displacement causes (1) The wire box is not firmly fixed, and the wire box is displaced during concrete pouring or vibration (2) Measures for correcting deviation of contact wire box by concrete vibration (1) Support must be added at the bottom of embedded wire box on the upper surface of prefabricated components (2) When concrete vibration is performed, contact with embedded wire box and wire pipe is strictly prohibited (3) Technical Specification for Fabricated Concrete Structures stipulates that: embedded wire pipe The position deviation of the electric box at the center line of the component plane is 20mm, and the height difference is 0~10mm.
2) Analysis on the causes of surface cracks of prefabricated components (1) The design drawings did not provide stiffeners at the openings of doors and windows as required by the specifications.
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Corrective measures (1) The design department shall design in strict accordance with the specifications.
4) Analysis on the causes of the three layers of pipelines on the composite slab exceeding the height of the post cast layer No design BIM was made in the design stage, no construction BIM was made in the construction stage, and no collision inspection was carried out for electromechanical pipelines and reinforcement.
The horizontal joint of the component is designed to be 20mm, and the joints between the insulation boards are directly filled with cement mortar.
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(2) During construction, establish the node construction BIM, check the rebar collision problem, reasonably arrange the process, reasonably conduct the process interpolation and coordination, reasonably layer, and demonstrate the hoisting sequence according to the reasonable process, so as to improve the construction efficiency and reduce the waste of construction period.
Corrective measures (1) During the design, the node design BIM was established, and the problem of rebar collision was solved, such as the collision of beam main reinforcement in four directions and the collision between beam main reinforcement and column main reinforcement.
Because the steel bars are dense and the space is limited at the beam column node, the main reinforcement of the column, the column stirrup, and the four direction beam reinforcement extend into the node, causing the steel bars collide, and the steel bars are complex, Unreasonable hoisting sequence and process coordination lead to construction confusion and low efficiency, affecting the construction period of the structure.
If the site is uneven, the cushion blocks need to be adjusted to ensure that the bottom cushion blocks are in the same plane, so as to ensure that the bottom prefabricated components are placed flat and evenly stressed; Second, the stacking layers of laminated plates should not exceed 5; Third, there should be no lack of cushion blocks between plates, and the vertical cushion blocks should be in a straight line.
Corrective measures (1) Take corresponding remedial measures; (2) Strengthen the on-site construction management to avoid the phenomenon of rebar deviation; (3) The information shall be fed back to the processing plant in time, and the hoop extension length shall be redesigned to avoid similar problems again.
Rectification measures.
After the components of the corrective measures are deepened, the drawings shall be reviewed and disclosed, and the design, construction and production parties shall confirm.
Without water stop measures, it becomes an indirect water trough of the external wall layer, which directly leads to leakage.
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Cause analysis (1) main reinforcement deviation; (2) The length of the reserved stirrup in the prefabrication plant is insufficient.
The design part 1) The hoisting efficiency at the beam column node is slow, the steel bars collide, and the process is unreasonable, which often causes rework.
The upper and lower rows of wooden blocks are not in a straight line, which is very easy to cause cracks.
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3) The pipelines of prefabricated components are missing, inconsistent with the on-site reservation, and the embedded pipes of some prefabricated components are found to be missing, offset, etc., resulting in the need to chisel grooves in prefabricated components during on-site installation, which is easy to damage the prefabricated components.
The prefabricated components are stacked at random on the site.
The embedded pipeline must be constructed according to the drawing without omission.
Analysis of the reasons for rework.
2) The design of lifting point location is unreasonable.
Set up a factory representative to master the production of components.
3) Analysis of the causes of the lack of structural grooves.
The inspection shall be strengthened before concrete pouring.
According to the BIM demonstration, establish the hierarchical flow chart of beam column nodes and primary and secondary beam nodes, and carry out the hoisting of composite beams and the binding of column stirrups according to the sequence of the flow chart.
Analysis of the causes of the leakage of some external wall members.
Cause analysis (1) Missing embedded pipe fittings during component processing; (2) The pipeline is not installed according to the drawing.
The wallboard did not turn up 600 according to the design, and no water stop grooves were left.
4) The main reinforcement of the wall is not in the stirrup at the node where the main reinforcement is not in the stirrup, which brings hidden danger to the structural safety.
Waterproof construction measures shall be taken at joints.
All cushion blocks should meet the specification requirements.
Hoisting and transportation can only be carried out after the inspection is qualified.
(2) The machine wire box can be embedded in the prefabricated laminated plate, and the pipeline material can be changed to PVC material.
The factory quality management shall be strengthened.
(2) Do a good job in the review of the detailed design drawing and the first sample inspection.
(2) Before lifting and transportation, reinforcement and corrective measures were not taken according to the design.
Therefore, corrective measures for this problem occurred (1) The design BIM was completed in the design stage, and various collision inspections were carried out, including reinforcement and electromechanical pipelines; Complete the construction BIM in the construction stage and conduct various collision inspections.
