JPH0530313U - Concrete floor slab with cavities - Google Patents

Abstract

(57) [Summary] (Corrected) [Purpose] To increase the span of concrete floor slabs with cavities and make them easier to manufacture. [Structure] A ridge is arranged on the upper surface, and a pretensioned PC concrete plate 1 in which a PC steel rod is passed under each ridge is arranged to form an embedded formwork 10, and a cavity is formed between the reinforced concrete layer 3 to be placed thereon. To make a groove in the groove between the ridges,
The cavity-forming core 2 or the partition plate was fitted.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 This invention relates to a hollow concrete slab.

[0002]

[Prior Art]

 As a conventional technique of making concrete slabs by transporting concrete plates to the site, laying them out side by side to form an embedded formwork, and then placing concrete on them and placing concrete, there is what is called a void slab. The cross section is shown in Fig. 7, and the state before pouring concrete is shown in Fig. 8. It consists of a number of inclined V-shaped rebars and rebars connecting the tops of the flat reinforced concrete plate A. The trusses B are arranged in parallel, the channel members C are laid between them, and the cast-in-place reinforced concrete D is placed on them. As the channel material C, a mold or a foamed polystyrene molded product is used.

[0003]

[Problems to be solved by the device]

 The hollow concrete floor slab of the above-mentioned conventional technology is manufactured by manufacturing a reinforced concrete board A with a truss B, and before or after carrying it to the site, the channel C is fixed by adhesion or the like, and it is fixed at the required position. Side-by-side concrete will be placed by lining them up to form an embedded formwork and then building rebar on it.

The work of securely fixing a large number of grooved members C (or expanded polystyrene square members) at predetermined positions between the respective trusses B requires a considerable amount of manpower and labor and is easily moved by impact, If moved, the shape of the cavity will be deformed, which will also affect the strength of the slab. An even more important problem is that the truss B is not so effective in increasing the bending rigidity of the reinforced concrete plate A, so that the length is limited to 2 to 3 m, and the floor plate made by using this as an embedded formwork The only thing that can be made is a short span of that length. The purpose of this invention is to develop a concrete floor slab containing a cavity without the above-mentioned problems.

[0005]

[Means for Solving the Problems]

 The hollow concrete floor slab of this invention is a rectangular plate in which longitudinally extending rough surface ridges are juxtaposed on the upper surface, and a plurality of pre-tensioned PC concrete plates with PC steel material passed under each ridge are provided. , The embedded formwork arranged side by side, and the cavity forming core material or partition plate that fits all or part of the concave grooves between the above-mentioned projections, and cast on the embedded formwork. And a reinforced concrete layer.

[0006]

[Action]

 The floor slab of this invention is mainly composed of an embedded formwork in which a plurality of pre-tensioned PC concrete plates with ridges lined up in a factory are lined up, and a reinforced concrete layer cast thereon, and a cavity is formed between them. The core material or partition plate to be formed is buried.

Since the above-mentioned PC concrete plate to be an embedded formwork is a rectangular plate in which rough surface ridges are arranged side by side in the longitudinal direction, concave grooves are formed between the ridges to form an embedded formwork of a cavity floor slab. Although it is the most suitable outer shape, what is more important is that the bending rigidity as an embedded formwork is greatly increased by introducing prestress by the above-mentioned ridge and the PC steel material below it. As a result, the length of the buried form becomes 6 to 7 m, which is more than double that of the conventional type shown in FIGS.

[0008]

【Example】

 1 to 5 are partial cross-sectional views of a fifth embodiment of the present invention, and FIG. 6 shows a state of one PC concrete plate 1 of the buried form 10 shown in FIG. 1 before cast-in-place concrete. The PC concrete board 1 is a rectangular board in which two rough ribs 1a extending in the longitudinal direction are arranged on the upper surface, and two in this example are arranged in parallel. Pretension is given to the PC steel material 1b which passes through the lower side of each ridge 1a. The upper surface of the ridge 1a is a rough surface formed by rolling a mesh roller during molding, that is, an uneven surface. This is unevenness to strengthen the joint with the in-situ concrete.

A hollow-forming core material 2 made of styrofoam that fits the groove is fitted to the groove formed between the protrusions 1a. The embodiment shown in FIG. 1 is an embedded formwork 10 in which the same core material 2 is housed not only between the ridges 1a of one concrete plate 1 but also in the groove between adjacent PC concrete plates 1 and 1. A reinforced concrete layer 3 is placed on top of it. Of course, the reinforcing bar 3a is incorporated before placing.

In the embodiment shown in FIG. 2, the expanded polystyrene core material 2 shown in FIG. 1 is replaced with a cavity-forming grooved partition plate 2a. The partition plate 2a is not inserted in the concave groove between the PC concrete plates 1 and 1, but the reinforced concrete layer 3 cast in-situ is inserted into the groove to strengthen the connection with the PC concrete plate 1.

As the cavity forming partition plate, in addition to the vinyl chloride grooved partition plate 2a shown in FIG. 2, a thin steel plate partition plate 2b as shown in FIG. 3 may be used, in which a lid plate is fitted in the concave groove. In the embodiment of FIG. 4, the shape of the Styrofoam core material 2 is slightly changed so that the rough surface provided on the side surface of the ridge 1a as well as the side surface is joined to the cast-in-place concrete 3. The number of sub-materials 2 was reduced to increase the joint area between the reinforced concrete layer 3 that entered the groove and the rough surface.

The embodiment shown in FIG. 5 is an example in which the core material is not a polystyrene foam but a square tubular core material 2c made of cardboard. Even if made of cardboard, there is no problem as a core material as long as it has the strength to withstand the external pressure of concrete pouring. In addition to the above embodiments, it goes without saying that various changes and applications can be made within the scope of the present invention according to the implementation conditions, and it is easily conceivable that the surface of the PC concrete plate is given a gibel line. .

[0013]

[Effect of the device]

 The pretensioned PC concrete board 1 of each of the above-mentioned examples was previously developed by the applicant as an embedded formwork material for general floor slabs, but according to the present invention, it is not a single embedded formwork material, It became the most important component of the hollow floor slab. That is, the rough ridges, which were only intended to increase the bending rigidity of the PC concrete plate, became the walls on both sides of the cavities, and the ridges on both sides of the cavities were pre-existing. Since the PC steel material with tension passes through, the bending resistance reduction due to the cavity is compensated to create a strong cavity wall, and the lower surface of the cavity-filled concrete floor slab of this consideration is made of PC steel rods. Since the completed floor slab is flexed under load and the lower surface is stretched to some extent, the tightening is only loosened and cracks do not occur on the lower surface, because it is tightened. These are unthinkable in the above-mentioned conventional technology.

In terms of practical use, the advantages of this invention are great. As described above, the positioning and fixing work of the cavity forming material, which was a troublesome work in the prior art, is simplified by just dropping it into the groove between the ridges, and both sides are surrounded by the ridges. Since the top surface of the frame is flat, there is no risk of the core material or partition plate being damaged, moved, or crushed by the worker's feet or equipment during construction. Therefore, the cavity can be formed by a material that is cheaper and weaker than the conventional one. Also, in the conventional type (Fig. 8), the truss B is taller than the channel C (see Fig. 7), so when stacking them, an interlocking work is required between the channel C and the concrete plate A above. Although it is indispensable and it is necessary to use the channel material C having the strength to withstand the load applied, it is expensive, but since the PC concrete board of the present invention has a ridge, it can be stacked as it is.

[Brief description of drawings]

FIG. 1 is a cross sectional explanatory view of an embodiment of the present invention.

FIG. 2 is an explanatory view of another embodiment of the present invention.

FIG. 3 is an explanatory view of still another embodiment of the present invention.

FIG. 4 is an explanatory view of still another embodiment of the present invention.

FIG. 5 is an explanatory view of still another embodiment of the present invention.

FIG. 6 is a perspective view of a main part of FIG.

FIG. 7 is a cross-sectional explanatory diagram of a conventional technique.

FIG. 8 is an explanatory perspective view of a conventional technique.

[Explanation of symbols]

 1 PC concrete board 2, 2C core material 2a, 2b Partition board 3 Reinforced concrete layer 10 Embedded formwork

Claims (1)

[Scope of utility model registration request] 1. An embedded formwork in which a plurality of concrete plates, each of which is a rectangular plate formed by arranging rough surface ridges extending in the longitudinal direction on the upper surface side by side, and PC steel material being arranged under each ridge, are arranged side by side. , A cavity-forming core material or partition plate adapted to all or part of the recessed grooves between the respective projections, and a reinforced concrete layer cast on the embedded formwork, A concrete floor slab with a hollow inside.