How to resist floating of cast in place concrete hollow floor

There is a special anti-floating structure, and the screws are fixed on the bottom plate and fixed with a special plastic bag.

The cast-in-place concrete hollow floor has negative moment reinforcement.

The cast-in-situ reinforced concrete hollow slab beamless floor technology is to embed the GBF high-strength composite thin-walled pipe into the floor, and after pouring concrete, it constitutes the cast-in-place reinforced concrete hollow slab beamless floor that does not need open beams.

It is a new type of beamless floor slab form with light self-weight, large stiffness, and it can form a plate-column system and a plate-column-shear wall system by adopting it. The key to this technology is the core-filler GBF high-strength composite thin-walled tube, which is a lightweight tube prefabricated from fiberglass cementitious material. This technology was first put into use in high-rise buildings in Changsha International Financial Building in August 1996, and it is more and more widely used in construction projects because the building has the advantages of wide range of application, excellent use function and low comprehensive cost.

But because the stress performance of cast-in-place reinforced concrete hollow slab beamless floor lacks more systematic research at present, its calculation method refers to the calculation method of solid slab more, and cast-in-place reinforced concrete hollow slab carries out internal force and reinforcement according to one-way slab, makes the reinforcement ratio of slab large. With the gradual popularization of this technology, the perfection of the calculation theory and method of cast-in-place reinforced concrete hollow core slab beamless floor becomes the key to further popularize this technology.

There is a special construction for the overall anti-floating, and the specific method is to fix the construction on the bottom plate, and then fix and tie it with a special belt.

Prefabricated hollow core slabs are not required in many places at present! The key is poor seismic resistance! (poor integrity), if it has been used, then the reinforcement method is to solve the interface joint of each slab, and the concrete cast-in-situ is one level higher than the concrete of the empty slab, and put it (2 longitudinal 8 Changyuan steel, transverse 8 steel bars @ 200) Tie it well!

Just make a hook at both ends!

First, calculate the concrete amount of the floor slab according to the design thickness (if it is a beam slab, the concrete amount of the beam should be included), and then calculate the volume of the inner mold according to the design number and specifications, and calculate the volume of concrete - the calculated volume of the inner mold is the quota volume.

1. Calculation method:

The volume of the plate The area of the plate The thickness of the plate.

The cast-in-place concrete slab is calculated by volume according to the dimensions shown in the design drawing. The volume occupied by the reinforcement bars, embedded iron parts and holes within a single area of the component is not deducted.

Beamed plates (including main and secondary beams and plates) are calculated according to the sum of the volume of beams and plates, beamless plates are calculated according to the sum of the volumes of plates and column caps, the plate heads of various types of plates extending into the wall are incorporated into the plate volume, and the ribs and foundation beams of thin shell plates are incorporated into the volume of thin shells.

The precast concrete slab is calculated by volume according to the dimensions shown in the design drawing. The volume of the steel bar, embedded iron parts and the holes within 300mm of a single size of 300mm is not deducted, and the volume of hollow slabs is deducted.

The template of the plate, the bottom template of the plate, the perimeter of the template, the bottom template of the plate, the net area of the bottom surface of the plate.

The perimeter formwork of the plate The exposed perimeter length of the plate The thickness of the slab.

Tianjin 2004 calculation rules: concrete, reinforced concrete formwork and support are calculated according to the concrete volume shown in the design and construction drawings.

The height of the concrete beam exceeds the increase price = the sum of the wall volume exceeded by the height of the concrete beam.

Prefabricated panels. Second, the concept of hollow floor slab:

Hollow floor is a kind of cast-in-place reinforced concrete hollow floor; It is also called cast-in-situ beamless hollow floor, which is a hollow beamless floor made of cast-in-place after installing the core mold product. The hollow floor includes steel bars, concrete, and a mandrel mold, and the mandrel is embedded in the reinforced concrete, which is characterized by the mandrel filled with lightweight materials.

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Because the thickness of the lower flange of the cast-in-place concrete hollow floor is thin, the lower flange is prone to air bags and bubbles when pouring, so the concrete slump should not be less than 150mm when pouring, and the maximum diameter of the concrete coarse aggregate should not be greater than 1 2 of the thickness of the lower flange and the width of the rib, and should not be greater than 31 mm, and the distribution and vibration should be carried out synchronously. 2) When pouring concrete, the construction equipment shall not be placed directly above the box. When pumping concrete, the falling height of concrete should be reduced as much as possible, and the impact force of concrete should be buffered by formwork when falling.

3) When the concrete is poured, the box will bear a large buoyant force, so when there is no steel bar above the box, the anti-floating steel bar needs to be laid, and the steel bar needs to be reliably connected with the formwork support with iron wire. A cushion block needs to be added between the steel bar and the formwork to ensure the thickness of the upper flange concrete. The diameter and spacing of the anti-floating reinforcement and the distance of the anchorage point of the tie should be determined in the construction plan after calculation.