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Two-way slabs without beams with columns and prestressed concrete

The subject of floor work has many elements. By building a house in Korat รับสร้างบ้านโคราช or building a house in general, must have knowledge of two-way slabs without flat stomach Two-way slabs without beams with columns and prestressed concrete

The details are as follows.

Two-way slab without beams

Floor slabs without flat beams are Concrete slab of the same thickness, uniform, whole sheet, reinforced with rebar to bear loads in two or more directions. and support columns directly without beams supporting any slabs The fact that the floor-to-floor slabs can reduce the height between floors from floor to floor. And it provides a lot of flexibility in the design of the position of the pole. The area is suitable for the construction of apartments, dormitories or hotels.

  • Reinforced steel for floor tensile strength.
  • 5″ to 12″ (125 to 305) thick, or approximately the span length divided by 33.
  • Suitable for areas that require light to medium loads on a short span or approximately 12′ to 24′ (3.6 to 7 m).
  • The position of the pillars should be square. or have similar patterns to form a uniform lattice
  • The advantages of the floor without beams are smooth. There is some flexibility to move the position of the pole.
  • The thickness of the plate without beams is smooth. is determined mainly by the amount of shear force at the head of the pillar especially the shear force penetrated

Two-way floor slabs without beams with pillars

The beamless floor slab has a pillar-headed slab that looks like a smooth slab without beams. but will increase the thickness of the slab at the head of the pillar supporting to increase shear strength and bending moment. These floor work also done by house builder in Ratchaburi รับสร้างบ้านราชบุรี as well.

  • Reinforced steel
  • Floor thickness 6″ to 12″ (150 to 305) or approximately equal to 36 span lengths.
  • The floor thickness has been increased to form a pillar to resist shear penetration.
  • Increasing the thickness of the floor to be the pillar base is 0.25 × the thickness of the floor.
  • The width of the backboard is 0.33 × the span of the pole.
  • The column capital base is used to replace the pole base with the same function.
  • Suitable for load slabs and mast spans from 20′ to 40′ (6 to 12 m).

4. Prestressed concrete

Prestressed concrete is The concrete is poured onto the form without the wire being pulled up to be stretched by a certain beam force. After the concrete has hardened, it reaches the standard strength. The wire is cut at both ends. Therefore, the concrete will be prestressed from the prayer line to bend a bit more into a prestressed concrete slab that has an increased ability to resist bending and bending moments. Make prestressed concrete slabs that can be placed across a longer span. and can bear more weight than ordinary concrete slabs. which will be made from the factory and back-pull prestressing is often done on the construction site. because it is too large to be transported from the factory

pre-stressed pre-stressed concrete

Pre-stressed pre-stressed concrete It begins by pre-stressing in concrete by pulling on the wire rod before pouring the concrete into it. After the concrete has hardened by age therefore releasing iron The iron will try to shrink back. At the same time the concrete is compressed. This gives the concrete a slight curve to support the weight further.

  • Pull the steel wire to hold it out. and then fasten the ends with anchor lines. by giving the wire a specified tensile unit value
  • Pour concrete into the formwork prepared to cover the wire. where the wire is in the middle of the formwork in the cross section and will be near the bottom in the longitudinal cut
  • When the concrete has fully hardened. So we cut or release the wire from the mounting bracket. The wire will try to pull itself back. which will be transferred to the concrete as a pre-stressed form This causes the concrete slab to bend as shown in the picture because the wire is near the bottom of the slab.
  • When the concrete slab is loaded It helps to balance the deflection with the compressive forces within the concrete that are just right.

The force that arises due to

  1. Static payload
  2. Compressive strength from the wire
  3. Combining Forms 1 and 2, Form 3.
  4. The sum when mixing concrete
  5. Load weight
  6. The sum of patterns 4 and 5 is subjected to prestressing. and will get the final form of prestressed concrete
  • However, when the wire is cut or released from the mounting platform in the first few minutes, the transfer of compression back from the wire to the mortise may not be as much as theoretically required. Because there may be some slip between the steel surface and the concrete.
  • Extra-strong wire can withstand higher tensile strength than ordinary wire. may be in the form of a wire group cable or steel bar

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