by The composite member is composed of prefabricated concrete members and post cast concrete, and is an integral stressed structural member formed in two stages; Composite floor is the most commonly used prefabricated horizontal component in prefabricated buildings.
The prefabricated layer of the laminated plate can be used as the permanent formwork of the upper cast-in-situ laminated layer, and the horizontal equipment pipeline can be laid in the cast-in-situ layer.
The mechanical and electrical systems of equipment in different functional buildings are very different, so the reserved and embedded parts and corresponding openings required on the prefabricated slabs of laminated slabs are also different.
Whether the pipeline is exposed or concealed, it will be reserved and embedded on the laminated plate more or less.
The accuracy of the detailed design of the reserved and embedded on the laminated plate will have a direct impact on the processing and production of prefabricated components and the construction and installation in the construction stage.
The commonly used composite plate is the truss reinforced concrete composite plate (60mm thick bottom plate).
The special structure of the truss reinforcement will also have a great impact on the reserved opening and the embedding of the wire box.
Combined with the detailed design of prefabricated building laminated floor and the practice of prefabricated building installation engineering, this paper mainly analyzes the existing common problems of the detailed design of the laminated floor and the later construction problems, and puts forward the optimization measures for revising the construction drawing design and the cooperation between the disciplines at the stage of the detailed design, so as to ultimately improve the efficiency and quality of the detailed design of prefabricated building components, In order to reduce the adverse impact on the processing and production of prefabricated components and the assembly construction of components.
On site stacking and installation I.
common mechanical and electrical reserved and embedded problems in the detailed design of composite slabs composite slabs are relatively simple components in the construction and implementation of prefabricated buildings.
However, in the process of engineering practice, the reserved and embedded parts on the composite slabs are missing or inaccurate due to the inadequate coordination between disciplines in the construction drawing stage and the lack of precision in the detailed design, resulting in a lot of rework for component processing and construction and installation, Thus greatly affecting the construction period and causing large economic losses.
The following lists the common reserved and embedded problems on the composite slab in combination with specific projects: (1) the design height of truss reinforcement is wrong, and the concealed laying pipe on the composite cast-in-place layer cannot pass through the truss reinforcement, which causes the need to cut grooves on the precast slab or add supports to cancel the upper chord of local truss reinforcement in site construction.
(2) There are many and concentrated local pipelines in the superimposed cast-in-place layer, and the concentrated and large-diameter pipelines cannot pass through the truss reinforcement, resulting in the removal of truss reinforcement and prefabricated plate in the concentrated part of the pipeline in the field construction.
In the field pipeline layout (3), the embedding of the electromechanical junction box is missing.
When there are many electromechanical systems or special needs, the detailed design often omits small system points, resulting in the installation of junction boxes in the field construction holes.
(4) The distance between the embedded position of the electromechanical junction box and the design point position deviates greatly, resulting in excessive deviation between the decoration and installation point position and the design requirement position, resulting in the need for re opening and installation of the junction box in site construction.
(5) The influence of truss reinforcement is not considered in the embedded and incoming direction of electromechanical junction box.
The embedded position of junction box is close to the truss reinforcement, and the incoming direction collides with the truss reinforcement, resulting in the re opening of junction box without locking nut after adjusting the incoming direction on site.
(6) The electromechanical junction box is embedded close to the edge of the prefabricated plate, and the junction box is damaged during hoisting and transportation.
The damaged junction box needs to be removed and reinstalled on site.
(7) The reserved holes for the downward vertical threading pipes of the electromechanical equipment are missing, resulting in the need to drill holes for the laminated prefabricated plates in the field construction.
(8) The fire fighting and water supply and drainage floor slabs are vertically penetrated, and the reserved openings of the composite precast slabs are missing, resulting in the need to cut the composite precast slabs and re open the holes in site construction.
(9) The fire fighting and water supply and drainage floor slabs are vertically penetrated, and the reserved opening positions and sizes of the composite precast slabs are wrong, resulting in the failure of penetration and installation of the upper and lower vertical pipes on the floor.
It is necessary to cut and expand the holes of the composite precast slabs in site construction.
(10) The embedded sleeve on the prefabricated slab of the composite floor slab is damaged during hoisting and transportation, and the sleeve reserved higher than the prefabricated slab surface is very easy to be damaged, resulting in the need to remove the damaged sleeve for reinstallation in site construction.
Site drawing II.
Common types of mechanical and electrical reservation and embedment of laminated floor slab in view of the above-mentioned various deepening design problems, it is necessary to classify and summarize the common types of mechanical and electrical reservation and embedment on the prefabricated slab of laminated floor slab, so as to confirm the provision of mechanical and electrical reservation and embedment in the early stage of deepening design and avoid omissions, and it is also necessary for the deepening designer of structural discipline to fully understand these systems.
1.
Electrical reservation and embedment of laminated floor (1) lighting system: the lighting system line pipe is concealed, and the light box is placed at the bottom of the board.
The light box of the lighting system is a common reserved and embedded component in residential and commercial buildings.
For residential projects with hardbound requirements, the lighting points at the bottom of the non suspended ceiling plate must be accurately reserved and embedded, and the non suspended ceiling spotlight junction box in the hardbound room must be accurately reserved in the laminated plate area.
(2) Fire protection system: it is required to reserve the embedded junction box at the bottom of the laminated prefabricated plate for the concealed laying of the fire protection system pipeline.
The reserved and embedded junction boxes of the fire protection system generally include: emergency lighting, evacuation indicator lighting, smoke detector in the automatic fire alarm system and fire emergency broadcasting.
(3) Strong current system: the control switch of the strong current system is set on the wall, and its wire pipe usually needs to reserve a circular through hole in the area of the laminated plate.
The concealed laying on the cast-in-situ layer of the laminated plate needs to be downward.
When the pipe is laid in the partition wall, it needs to reserve a circular through hole in the laminated precast plate.
(4) Other special requirements: there are often special reserved and embedded requirements in hardbound residential projects.
For example, the security infrared reflection device, electric curtain and smart home need to reserve junction boxes at the bottom of the board.
2 reserved openings in the laminated floor slab (1) openings in the flue and air shaft: generally, there will be structural beams around the flue and air shaft on the floor, but the smaller flue and air shaft will be directly set with rectangular openings in the floor slab.
If the openings are at the edge of the laminated floor slab, the truss reinforcement of the laminated floor slab will not pass through, resulting in poor overall rigidity of the installation direction of the laminated slab.
Therefore, in the construction drawing design stage and assembly split scheme, it is necessary to avoid large reserved holes on the plate..
