by Source network.
If there is an infringement connection, delete the composite component, which is composed of prefabricated concrete components and post cast concrete, and is an integral load-bearing structural component formed in two stages; Composite floor is the most commonly used prefabricated horizontal component in prefabricated buildings.
The precast layer of the composite slab can be used as the permanent formwork of the upper cast-in-place composite layer, and the horizontal equipment pipeline can be laid in the cast-in-place layer.
The mechanical and electrical systems of equipment in different functional buildings are quite different, so the reserved and embedded parts and corresponding openings required on the precast slabs of the composite slabs are also different.
Whether the pipeline is installed in the open or concealed way, it will be more or less reserved and embedded on the composite plate.
The accuracy of the detailed design of the reserved and embedded on the composite plate will have a direct impact on the processing and production of the prefabricated components and the construction and installation in the construction stage.
The commonly used composite plate is truss reinforced concrete composite plate (60mm thick base plate), and the special structure of truss reinforcement will also have a great impact on the reserved opening and the embedded wire box.
Combined with the in-depth design of composite floor slab of prefabricated buildings and the installation engineering practice of prefabricated buildings, mainly from the analysis of the existing common problems in the in-depth design of composite floor slab and later construction problems, this paper proposes the optimization measures to improve the efficiency and quality of the in-depth design of prefabricated building components by revising the construction drawing design and providing information and cooperation between disciplines in the in-depth design stage, In order to reduce the adverse impact on the processing and production of prefabricated components and component assembly construction.
1、 Common mechanical and electrical reservation and embedment problems in the deepening 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 lack or inaccuracy of reservation and embedment on the composite slabs caused by the inadequate coordination between disciplines in the construction drawing stage and the insufficient fineness of the deepening design has caused more rework for component processing and construction installation, This will greatly affect the construction period and cause great economic losses.
Common problems of reservation and embedment on the composite slab are listed below in combination with specific projects: (1) The design height of truss reinforcement is wrong, and the concealed laying pipe on the composite cast-in-situ layer cannot pass through the truss reinforcement, which causes that the on-site construction requires notch cutting on the precast slab or adding support to cancel the upper chord of local truss reinforcement.
(2) There are many and concentrated local pipelines in the superimposed cast-in-situ layer, and the concentrated and large diameter pipelines cannot pass through the truss reinforcement, resulting in the removal of truss reinforcement and precast slab in the local part of the concentrated pipeline during on-site construction.
(3) Electromechanical junction boxes are missing, and small system points are often omitted in the detailed design when there are many electromechanical systems or special needs, resulting in on-site construction opening and installation of junction boxes.
(4) The distance deviation between the embedded position of the electromechanical junction box and the design point position is large, which causes the deviation between the decoration installation point and the design requirement position to be too large, resulting in the need to re open the hole to install the junction box for 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 slab, 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 hole for the downward vertical threading pipe of the electromechanical equipment is missing, resulting in the need to drill holes for the laminated precast slab in the field construction.
(8) The fire protection and water supply and drainage floor slabs are vertically threaded, and the reserved holes in the laminated precast slabs are missing, which causes that the on-site construction needs to cut the laminated precast slabs and reopen them.
(9) The fire protection and water supply and drainage floor slab is vertically threaded, and the reserved opening position and size of the laminated precast slab are wrong, which makes the upper and lower risers of the floor unable to be connected and installed.
The on-site construction requires opening, cutting and reaming of the laminated precast slab.
(10) The embedded casing on the precast slab of the superimposed floor slab is damaged in the process of hoisting and transportation, and the casing reserved higher than the surface of the precast slab is very easy to be damaged, resulting in the need to remove the damaged casing and reinstall it in the field construction.
2、 Common electromechanical reservation and embedment types of laminated floor slab In view of the above various deepening design problems, it is necessary to classify and summarize the common types that need to be reserved and embedded on the prefabricated slab of laminated floor slab, so as to confirm the electromechanical reservation and embedment information at the initial stage of deepening design and avoid omissions, and it is also necessary for the deepening designer of the structural discipline to fully understand these systems.
1.
Electrical reservation and embedment of superimposed floor slab (1) Lighting system: the lighting system conduit is concealed and the light box is placed at the bottom of the slab.
The light box of the lighting system is a common reserved and embedded component in residential and commercial buildings.
The embedded light box must be accurately reserved at the lighting point at the bottom of the non ceiling panel for residential projects with fine decoration needs, and the junction box for non ceiling spotlights in the fine decoration room needs to be accurately reserved in the laminate area.
(2) Fire protection system: the embedded junction box shall be reserved at the bottom of the laminated precast slab when the fire protection system pipeline is determined to be laid in a concealed way.
The junction boxes reserved and embedded in the fire protection system usually include: emergency lighting, evacuation indicating lighting, smoke detector in the automatic fire alarm system, fire emergency broadcast, etc.
(3) Strong current system: the control switch of the strong current system is set on the wall, and its wire tube usually needs to reserve a circular threading 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 routed in the partition wall, it needs to reserve a circular threading hole in the laminated prefabricated plate.
(4) Other special needs: there are often special needs for reservation and embedment in hardbound residential projects, such as security infrared radiation devices, electric curtains, and smart homes, which need to reserve junction boxes at the bottom of the board.
2.
Reserved openings in the composite floor (1) Flue and air shaft openings: usually there will be structural beams around the floor flue and air shaft, but smaller flue and air shafts will directly set rectangular openings on the floor.
If the openings are at the edge of the composite floor, the truss reinforcement of the composite floor will be unable to be connected, resulting in poor overall stiffness in the installation direction of the composite floor.
Therefore, in the construction drawing design stage and the assembly and disassembly scheme, it is necessary to avoid reserving holes on large slabs..
