JPH0346626B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for demolding a formwork for forming a horizontal slab with reinforcing ribs, and more specifically, the present invention relates to a method for removing a formwork for forming a horizontal slab with reinforcing ribs. The formwork used for the horizontal slab with unidirectional reinforcing ribs, which is one of the structures, is
The present invention relates to a method for easily removing the cast concrete from the mold after it has hardened, and for allowing the formwork to be used repeatedly.

In recent years, in medium-to-high-rise buildings such as medium-to-high-rise apartment buildings or medium-to-high-rise office buildings, there has been a problem of sound insulation between the upper and lower floors, and to solve this problem, flat horizontal slabs have been introduced. tends to increase in thickness.
However, increasing the thickness of a horizontal slab can have a significant mechanical impact not only on the slab itself but also on the entire building.

For example, an increase in vertical load will result in an increase in horizontal load, which may require the cross-sectional dimensions of structural members to be increased, which may result in an increase in material costs and push up the construction cost of the building. There are situations where this is not the case.

In order to deal with such problems, it was devised to form reinforcing ribs on the lower surfaces of floors and ceilings.

In other words, by attaching reinforcing ribs to a flat horizontal slab, you can obtain the same effect as increasing the thickness of the horizontal slab, increase the moment of inertia, and effectively use reinforcing bars. They succeeded in increasing the strength and rigidity of the slab and improving its vibration and noise insulation properties.

However, the work of attaching reinforcing ribs to this horizontal slab involves various problems.

The most problematic issue is that when forming the reinforcing ribs attached to the horizontal slab, in order to form the recesses between the reinforcing ribs, a formwork with the recess shape as the surface shape is used to pour concrete. It is troublesome to place the concrete on a suitable support, pour concrete from above, remove the support after the poured concrete has hardened, and then remove the formwork. It is severely damaged and soiled and cannot be reused.

Various methods have been proposed to facilitate this process, but some representative ones include:
(1) A method in which a release agent is applied to the outside surface of the formwork before concrete is poured; (2) When the formwork is removed, the outside surface of the formwork and the inside of the recess are in a vacuum; There is a method in which a through hole is drilled through the upper and bottom surfaces of the formwork, and the air is press-fitted between the inner surface of the recess in the poured concrete and the outer surface of the formwork using the through hole.

However, method (1) has the disadvantage that the mold release agent used remains on the concrete surface after hardening, and it is troublesome to remove the residual mold release agent. However, the poured concrete firmly adheres to the formwork, which not only makes it impossible to remove the formwork even when air is injected, but also causes damage and stains, making it difficult to withstand repeated use. .

The method of demolding a horizontal slab forming formwork with reinforcing ribs of the present invention was invented in view of the problems in the conventional methods described above, and its gist is as follows:
A boundary layer is coated with a thin film of synthetic resin to prevent direct contact with the poured concrete on the outer surface of the formwork except for the bottom surface, and a feeder is used to pressurize air between the inner surface of the boundary layer and the outer surface of the formwork. After installing air means on the formwork side and placing the formwork appropriately on the support, concrete is poured with a boundary layer interposed between it and the outside surface of the formwork, and after the poured concrete hardens. By removing the support and injecting air between the inner surface of the boundary layer and the outer surface of the formwork using an air supply means, the formwork is removed from the poured concrete with the boundary layer remaining in the poured concrete. , prevent the formwork from coming into direct contact with the poured concrete,
Makes demolding of the formwork easier and prevents damage to the formwork.
It also prevents staining and is designed to withstand repeated use.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the reinforcing ribbed horizontal slab-forming mold demolding method of the present invention will be disclosed below with reference to the accompanying drawings.

A formwork 1 whose surface shape is a concave shape formed by ribs on the lower surface of a horizontal slab forming a floor, a ceiling, etc. is provided with a through hole 2 penetrating between the upper surface 1a and the bottom surface 1b, and the bottom surface 1b is excluded. Boundary layer 3 is placed on the outer surface that is in direct contact with the poured concrete (hereinafter, the outer surface excludes the bottom surface) so that the inner surface of boundary layer 3 and the outer surface of formwork 1 are in close contact or almost in close contact with each other. It is formed by covering with a thin film of synthetic resin by a suitable method such as fitting or coating.

Such a formwork 1 is coated with a boundary layer 3 on a support A formed by, for example, laying a formwork plywood 5 horizontally on the upper surface of a bow beam 4 made of a steel frame or the like. With the bottom surface 1b, which is not covered, facing downward, a spacer 6, which is either integrated with or separate from the formwork 1 of a substantially plate-like body as shown by the dashed line in the figure, is interposed in the gap between them, or with the spacer 6 interposed therebetween. It should be placed appropriately without causing any problems.

Thereafter, concrete 7 is poured onto the upper surface of the support A on which the formwork 1 is placed, from the upper surface of the formwork 1.
...With a boundary layer 3 interposed between the outer surface and the outer surface,
The cast concrete 7 is poured to a thickness that has an allowable strength as a horizontal slab, and after the poured concrete 7 has hardened, the support A formed by the bow beam 4 and the formwork plywood 5 is removed, and the formwork 1 is completely One end of a tubular body 8 such as a pipe or hose is connected to the hole 2, and the other end of the tubular body 8 is connected to a compressor (not shown). By means B, air is forced into the space between the outer surface of the formwork 1 and the inner surface of the boundary layer 3.

Therefore, the formwork 1 is removed with the boundary layer 3 remaining in the poured concrete 7. Thus, reinforcing ribs D are formed on the horizontal slab C.

The boundary layer 3 may be left in the poured concrete 7 or removed.

If a lubricant such as lubricating oil is appropriately interposed between the inner surface of the boundary layer 3 and the outer surface of the mold 1, the mold 1 can be demolded more easily.

At this time, the presence of the boundary layer 3 prevents the lubricant from remaining in the poured concrete.

In the illustrated example, the formwork 1 is defined as having a cubic or rectangular parallelepiped shape, but if at least one of the side surfaces of the outer surface is an inclined surface, as will be described later, the poured concrete The frame 1 is pulled out against the force of pressing it from five directions, and has the effect of making the mold removal work even smoother.

In this case, it is also considered that the through hole 2 is bored through the space between the inclined side surface of the outer surface and the bottom surface 1b.

Here, the formwork 1 is made of a material such as metal such as a steel plate, foamed plastic such as foamed polystyrene, foamed urethane, or foamed polyethylene, rubber, or plywood, and has a block shape or only an outer shape.

When the formwork 1 is formed of a plate-shaped material, the bottom surface 1b is made an opening surface, and the through holes 2 as the air supply means B may be provided by a method described later.

Further, as the boundary layer 3 made of a thin synthetic resin, a thin sheet made of a synthetic resin such as polypropylene, polyethylene, or vinyl chloride is used, or the same material as the sheet is coated.
After coating, either cure the material or vacuum form the material such as polyethylene or vinyl chloride to shape the inner surface of the formwork 1.
It is formed to cover the outer surface of the formwork 1 by means of a fitting relationship using a material made to match the outer surface shape. In particular, the use of polyolefin plastics such as polypropylene with a small coefficient of friction has a great effect on demolding work.

Here, it is not possible to prevent the release agent from being applied to the outer surface of the boundary layer 3.

FIG. 2 shows another embodiment of the air supply means B, in which the air supply portion E of the air supply means B is approximately box-shaped with a thin cylindrical shape or a thin rectangular tube shape and a hollow interior. , a continuous opening or a discontinuous opening is provided on the edge side of the upper surface plate, and air outlet 9a is provided.
and an air outlet main body 9 having an opening in the lower plate into which a tube body described later can be inserted; An appropriate number of holes 10a are formed in the insertion portion existing inside the box, or, although not shown, the end edge portion of the tube faces the opening of the bottom plate of the box, and holes 10a are formed in the insertion portion of the tube. This figure shows a pipe 10 for a press-fit air flow path which is a tubular body that does not form a pipe.

Therefore, the air supply portion E having the above configuration is connected to the formwork 1.
A recessed portion 1 having a depth such that the upper surface and the surface of the air outlet main body 9 can be accommodated flush with each other.
1 is formed, and between the bottom surface of the concave portion 11 and the bottom surface of the formwork 1, a through hole 12 for inserting the press-fit air flow path pipe 10 of a tube whose one end is inserted into the opening of the bottom plate of the air outlet main body 9 is formed and installed in the formwork 1.

The air feeding means B is constructed by connecting the air feeding portion E installed in the formwork 1 to an external compressed air blowing means such as a compressor (not shown). In the figure, 13 is a sealing member such as a packing.

Here, the lower surface plate of the main body of the air outlet 9, the side plate, and the pipe 10 located in the through hole 12 can be omitted as appropriate.

Further, if such an air supply portion E is used, it is convenient to provide the air supply means B on the side of the formwork 1 when the formwork 1 is formed of a plate-shaped material as described above. An example of this is shown in FIG. 14 in the diagram
is a holding member that is appropriately provided when installing the air supply portion E in the formwork 1.

By providing the main body of the air outlet 9 in the air supply means B in this way, the main body of the air outlet 9 acts like a nozzle and efficiently connects the inner surface of the boundary layer 3 and the outer surface of the formwork 1. Air can be press-fitted.

In the embodiments shown in FIGS. 2 and 3, the side surface 1c of the outer surface of the formwork 1 is sloped so that it can be easily removed from the poured concrete 7 of the formwork 1. .

In the method for demolding a formwork for forming horizontal slabs with reinforcing ribs of the present invention as described above, a boundary layer is formed by coating the entire outer surface of the formwork, which is in direct contact with the poured concrete, with a thin film of synthetic resin. At the same time, by providing an air supply means on the formwork side, it is possible to prevent the poured concrete from sticking to the formwork, and to prevent the formwork from being removed by the air that is forced in between the inner surface of the boundary layer and the outer surface of the formwork. Since pressure is applied, the mold can be easily demolded even if the outer surface of the mold does not have a sloped surface for punching.

In addition, since the formwork does not come into direct contact with the poured concrete, there is little damage and no staining.
It can withstand repeated use, and has the effect that the cost required for formwork can be estimated at a low cost within the construction cost.

Furthermore, since no mold release agent is used, it is possible to beautifully finish the surface of the poured concrete after the formwork has been removed. Furthermore, even if a lubricant is applied to the outer surface of the formwork to facilitate demolding, there is a boundary layer between it and the poured concrete, which may stain the concrete surface or make it difficult to remove the lubricant. It never becomes a problem. In addition, since the boundary layer is left in the poured concrete when the formwork is demolded, there is no need to cover the formwork with the boundary layer in a strongly fixed state, and there is no need to cover the formwork with the boundary layer. is easy.

Furthermore, since the boundary layer is formed from a thin film of synthetic resin, it is easy to remove it from poured concrete.

[Brief explanation of drawings]

Figure 1 is a longitudinal cross-sectional view of the formwork used in the construction method of the present invention placed on a support and concrete poured, and Figures 2 and 3 are views of the formwork and air supply means. It is a longitudinal explanatory view showing another example. A: support body, B: air supply means, C: horizontal slab,
D: Reinforcement rib, E: Air supply part. 1: formwork, 2: through hole, 3: boundary layer, 4: bow beam, 5: plywood,
6: Spacer, 7: Concrete, 8: Pipe body,
9: Air outlet body, 10: Pipe, 11:
Recessed portion, 12: Through hole, 13: Sealing member.

Claims (1)

[Claims] 1. The entire outer surface of the formwork that is in direct contact with the poured concrete, excluding the bottom surface of the formwork whose surface shape is the shape of a recess formed by ribs on the lower surface of the floor and ceiling, is covered with the poured concrete. A boundary layer is formed by covering the boundary layer with a thin synthetic resin, and an air supply means is provided on the formwork side to pressurize air between the inner surface of the boundary layer and the outer surface of the formwork, and a boundary layer is formed on this outer surface. After placing the molded formwork appropriately on the support, concrete is poured with a boundary layer interposed between it and the outside surface of the formwork, and after the poured concrete has hardened, the support is removed and the air supply means is placed. The formwork is cast by injecting air between the inner surface of the boundary layer and the outer surface of the formwork.The formwork is removed from the concrete to form a horizontal slab with reinforcing ribs, with the boundary layer remaining in the poured concrete. Method. 2. The air supply means is a thin cylindrical or rectangular cylindrical hollow box-like structure with continuous openings or discontinuous openings on the edge side of the upper plate, and a lower plate. Insert the air outlet body from the opening in the lower plate of the air outlet body until the end edge abuts the inner surface of the upper plate, and make an appropriate number of holes in the insertion part. Formation of a horizontal slab with reinforcing ribs according to claim 1, comprising: a pipe body with a perforation therein; a compressor connected to the pipe body; and a formwork provided with the air supply means. Formwork removal method. 3. The method for demolding a horizontal slab forming formwork with reinforcing ribs according to claim 1 or 2, wherein a slipping material is interposed between the inner surface of the boundary layer and the outer surface of the formwork.