JP7448084B1 - Floor structure and floor structure construction method - Google Patents

Abstract

The present invention provides a floor structure and a floor structure construction method that reduce weight and the amount of concrete used. A floor structure 20 includes a concrete part 40 and a wooden board 21 on the lower surface. A plurality of void members 22, which are lighter than concrete, are arranged on the upper surface of the wooden board 21. Furthermore, rib portions 41 are formed on the wooden board 21 on both sides of the void member 22 in the X direction, and rib portions 42 are formed between the void members 22 in the X direction. Further, a rib portion is formed on the wooden board 21 between the void members 22 in the Y direction. [Selection diagram] Figure 1

Description

The present disclosure relates to a floor structure that is made of reinforced concrete and has wooden boards arranged on the bottom surface, and a floor structure construction method.

Sometimes the ceiling is made of wood. In this case, if the entire floor structure including the ceiling was made of wood, the floor structure would need to be thicker and heavier in order to obtain the necessary strength. Therefore, a floor structure is known in which the lower surface of the floor structure that can be seen as a ceiling is made of wood, and the upper part of the floor structure is made of reinforced concrete as a structure (for example, see Patent Document 1). The floor structure described in Patent Document 1 includes an RC (reinforced concrete) slab and a CLT panel provided along the lower surface of the RC slab.

JP2022-167555A

However, in the technique described in Patent Document 1, the thickness of the RC slab is constant. For this reason, even a floor structure made of wood and RC slabs is heavy. In addition, there was a need to further reduce the amount of concrete used in order to reduce weight and CO2 emissions.

A floor structure that solves the above problem is a floor structure that includes a concrete part made of reinforced concrete and a wooden board placed on the lower surface, and the wooden board is used as a formwork on the upper surface of the wooden board. A plurality of screws are embedded in the wooden board and the concrete part at a distance to integrate them, and the void member forming the rib part of the concrete part can be fixed therebetween. The void member is made of a material having a lower specific gravity than the concrete of the concrete portion.

Further, a floor structure construction method that solves the above problem is a floor structure construction method that constructs a floor structure including a concrete part made of reinforced concrete and a wooden board placed on the lower surface, the method comprising: The wooden board, on which a plurality of void members made of a material having a specific gravity smaller than concrete is fixed, is attached to the upper end of a beam formwork that forms a pair of spaced apart concrete beams that are integrally formed with the concrete part. by placing reinforcing bars to be buried in the concrete part on top of the wooden boards, and then pouring concrete using the beam formwork and the wood boards as formwork. A concrete portion and the concrete beam are formed.

According to the present invention, it is possible to reduce the weight and the amount of concrete used.

It is an explanatory view explaining composition of a floor structure in an embodiment. 2 is a sectional view taken along line 2-2 in FIG. 1. FIG. 3 is a sectional view taken along line 3-3 in FIG. 2. FIG. It is a flowchart explaining the procedure of the floor structure construction method in an embodiment. It is a perspective view explaining the state where a void member and a screw are fixed on a wooden board in a floor structure construction method of an embodiment. FIG. 2 is an explanatory diagram illustrating a state in which reinforcing bars are placed after the wooden boards and beam formwork are placed in the embodiment. It is an explanatory view explaining composition of a floor structure in an example of a change.

An embodiment of a floor structure and a floor structure construction method will be described below with reference to FIGS. 1 to 6. Here, we will explain the floor structure that constitutes the ceiling of a room in an employee dormitory and the floor immediately above the room. The ceiling of the room is made of wood.

1 is a cross-sectional view of the floor structure 20, FIG. 2 is a cross-sectional view taken along line 2-2 in FIG. 1, and FIG. 3 is a cross-sectional view taken along line 3-3 in FIG. FIG. 2 shows only the upper part of the wooden board 21, and the dotted portions in FIG. 2 are areas where screws 23 and rib reinforcing bars 37, which will be described later, are embedded.

As shown in FIG. 1, the floor structure 20 is constructed between a pair of spaced girders 15. The girder 15 is a concrete beam that is integrated with the concrete that constitutes the slab of the floor structure 20.

The floor structure 20 includes a wooden board 21 disposed on the lower surface, a plurality of void members 22, a plurality of screws 23, lower end reinforcements 31, upper end reinforcements 33, rib portion reinforcing bars 37, and a concrete portion 40.

The wooden board 21 is made of CLT (Cross Laminated Timber). This CLT is a wood-based material in which laminated boards (lamina) are arranged and then laminated and bonded so that the fiber directions are perpendicular to each other. This wooden board 21 has dimensions of about 4 m x about 1 m in length and width, and has a thickness of about 120 mm.

A plurality of void members 22 are fixed on the wooden board 21 and spaced apart from each other over the entire surface of the wooden board 21. Specifically, the plurality of void members 22 are arranged vertically and horizontally on the wooden board 21. The void member 22 is a member made of a material having a specific gravity smaller than that of the concrete part 40, and is made of, for example, bead-method polystyrene foam, which is a foamed plastic type, and has a size of 400 mm in width x 600 mm in length and 90 mm in thickness. ing. Specifically, as the void member 22, the product name "Sound Insulating Yuka Void (registered trademark) T-1" manufactured by Sansho Formtech Co., Ltd. is used in half.

Ribs 41 and 42 of the concrete portion 40 are formed between the void members 22 in the X direction of the floor structure 20 and at the ends of the void members 22 in the X direction. The rib portions 41 and 42 are arranged so that the rib portions 41 and 42 are located at locations where thickness is required in the floor structure 20 in order to maintain the strength of the floor structure 20. In this embodiment, the rib portions 41 and 42 are arranged at equal intervals in the X direction. In each of the rib portions 41 and 42, screws 23 are embedded in a row and spaced apart from each other.

Further, as shown in FIGS. 2 and 3, rib portions 45 of the concrete portion 40 are formed between the void members 22 in the Y direction of the floor structure 20 and at the ends in the Y direction. This Y direction is a direction perpendicular to the X direction. Note that, unlike the rib portions 41 and 42, the screws 23 and the rib portion reinforcing bars 37 are not embedded in this rib portion 45. That is, in this embodiment, a plurality of void members 22 and rib portions 41, 42, and 45 are provided on the entire surface of the wooden board 21.

Furthermore, as shown in FIGS. 1 and 3, lower end reinforcements 31, upper end reinforcements 33, rib portion reinforcing bars 37, etc. are buried in the concrete portion 40 of the floor structure 20.
The lower end reinforcing bars 31 are reinforcing bars placed at the bottom of the floor structure 20. The lower end reinforcing bars 31 are configured such that a plurality of spaced apart reinforcing bars 31a extending in the X direction and a plurality of spaced apart reinforcing bars 31b extending in the Y direction are arranged so as to be perpendicular to each other.

The upper end reinforcing bars 33 are reinforcing bars arranged at the upper part of the floor structure 20. Similar to the lower end reinforcement 31, this upper end reinforcement 33 is also configured such that a plurality of spaced apart reinforcing bars 33a extending in the X direction and a plurality of spaced apart reinforcing bars 33b extending in the Y direction are arranged so as to be orthogonal to each other. Ru.
In this embodiment, the ends of the lower end reinforcement 31 and the upper end reinforcement 33 extend so as to be embedded in the girder 15.

On the other hand, rib portion reinforcing bars 37 are arranged in the rib portions 41 and 42. The rib portion reinforcing bars 37 include a plurality of U-shaped spaced apart rib reinforcing bars 37a that protrude downward and a plurality of spaced apart rib main bars 37b extending in the Y direction. Each rib reinforcement 37a is arranged so as to extend from above the upper end reinforcement 33 to around the center of the screw 23.

(Construction method of floor structure 20)
Next, a method of constructing the above-described floor structure 20 will be explained using FIGS. 4 to 6.
First, as shown in FIG. 4, a void member and screws are fixed to a wooden board (step S11).

Specifically, as shown in FIG. 5, a plurality of void members 22 are fixed to the upper surface of the wooden board 21 in a spaced manner. Here, the void member 22 is fixed to the wooden board 21 using bolts (not shown) or the like. Furthermore, a plurality of screws 23 are driven onto the wooden board 21 to fix it. In this case, the screws 23 are arranged in one row between the void members 22 in the X direction and at the end of the wooden board 21 in the X direction relative to the void members 22 with equal gaps.

Next, wooden boards and formwork are installed (step S12).
Specifically, as shown in FIG. 6, a wooden board 21 with void members 22 and screws 23 fixed to the upper surface is placed on the upper end surfaces of a pair of spaced formworks 50. Here, the pair of formworks 50 spaced apart are beam formworks for forming the girders 15 formed at both ends of the floor structure 20. Furthermore, formwork (not shown) for other parts covering the concrete portion 40 of the floor structure 20 is placed.

Then, reinforcing bars are placed (step S13).
Specifically, the lower end reinforcing bars 31, the upper end reinforcing bars 33, and the rib portion reinforcing bars 37 are placed on the wooden board 21 placed on the formwork 50.

Next, concrete is placed (step S14).
Specifically, fresh concrete is poured into a formwork including the wooden board 21 and the formwork 50, and then cured. After the concrete hardens, the formwork including the formwork 50 is removed.
Through the above steps, the floor structure 20 shown in FIG. 1 is constructed.

(Action of this embodiment)
Since the rib portions 41 and 42 made of reinforced concrete are provided between the void members 22, the weight of the floor structure 20 is reduced while maintaining the strength of the floor structure 20.

According to this embodiment, the following effects can be obtained.
(1) In this embodiment, a plurality of void members 22 made of a material having a specific gravity smaller than that of the concrete portion 40 are provided on the wooden board 21 in a spaced-apart manner. Therefore, the weight of the floor structure 20 can be reduced by the amount of the void member 22.

(2) In this embodiment, rib portions 41 and 42 in which rib portion reinforcing bars 37 are embedded are provided at both ends of the void member 22 and both ends of the wooden board 21. Thereby, the strength of the floor structure 20 can be ensured by configuring the portions of the floor structure 20 that require strength as the rib portions 41 and 42.

(3) In this embodiment, after the wooden board 21 to which the void member 22 and the screws 23 are fixed is placed on the formwork 50, concrete is poured. Thereby, the wooden board 21 can be used as a formwork for constructing the lower surface of the concrete portion 40 of the floor structure 20.

(4) In this embodiment, the void member 22 and the screws 23 are fixed on the wooden board 21. Therefore, the concrete portion 40 of the floor structure 20 and the wooden board 21 can be efficiently integrated using the screws 23. Furthermore, by fixing the void member 22 to the wooden board 21, the rib portions 41, 42, 45 with the void member 22 arranged at desired positions can be efficiently formed on the wooden board 21.

(5) In this embodiment, the rib portions 41 and 42 are provided in the X direction, and the rib portion 45 is provided in the Y direction. Thereby, sound reflection that tends to occur when the rib portions 41 and 42 have an elongated shape can be suppressed.

(6) In this embodiment, the wooden board 21 is placed on the formwork 50 that forms the girder 15. Thereby, the concrete portion 40 of the floor structure 20 can be efficiently constructed integrally with the girder 15.

This embodiment can be modified and implemented as follows. This embodiment and the following modified examples can be implemented in combination with each other within a technically consistent range.
- In the above embodiment, a plurality of void members 22 of the same size are arranged and fixed at intervals in the vertical and horizontal directions on the entire surface of the wooden board 21. As a result, the void member 22 and the rib portions 41, 42, 45 were provided on the entire surface of the wooden board 21. The size and arrangement of the void member placed on the wooden board 21 are not limited to these. For example, depending on the strength of the floor structure 20, regions that do not require strength may be replaced with void members, and the void members may have different sizes. Furthermore, in the above embodiment, the rib portions 41, 42, and 45 are provided in the X direction and the Y direction in the wooden board 21, but if the rib portion 45 is used in a building where sound reflection is not a concern, the rib portion 45 may not be provided. Good too.

Furthermore, instead of fixing the void member 22 to the entire surface of the wooden board 21, the void member 22 may be provided only to a part of the wooden board 21. For example, the area where the water area is arranged may be an area where the floor is lowered without providing the void member 22.
Specifically, the floor structure 70 shown in FIG. 7 includes a wooden board 21 forming a lower surface and a concrete portion 71 made of reinforced concrete. A plurality of spaced apart void members 22 are arranged in an area A1 on the left side of the upper surface of the wooden board 21. Further, in this region A1, rib portions 72 and 73 of the concrete portion 71 are formed between the void members 22 and in the X direction of the void members 22, respectively. Note that rib portion reinforcing bars (not shown) are embedded in the rib portions 72 and 73, similarly to the rib portions 41 and 42 of the above embodiment.

Further, screws 23 are buried at intervals L1 so as to span the rib portions 72 and 73 between the void member 22 and the wooden board 21. A plurality of screws 23 are arranged in a line in a direction perpendicular to the paper plane of FIG.
Further, in a region A2 on the right side of the upper surface of the wooden board 21, a flat portion 75 is formed where the thickness portion of the void member 22 and the upper surface thereof are lowered. In this area A2, a water system is arranged, and in the plane part 75, slab lines (not shown) are embedded. Also in the plane portion 75, the screws 23 are buried at intervals L1. That is, the screws 23 are fixed at the positions (positions where they can be fixed) assuming that the void member 22 is provided on the wooden board 21.
Furthermore, in the floor structure 70, a small beam may be provided around the water area (around the flat part 75, such as the rib part 73, whose upper surface is lowered). In this case, a wooden board to which the void member is fixed to the upper surface and a wooden board to which the void member is not fixed may be placed side by side with a small beam in between.

- In the above embodiment, the void member 22 was formed on the wooden board 21 using the void member 22. The void member 22 is not limited to being made of bead-method polystyrene foam, and may be any member whose overall specific gravity is smaller than that of concrete. In this case, the void member is preferably a member having a strength capable of resisting the pressure of concrete to be placed, and for example, a solid container having a hollow interior may be used.

- In the above embodiment, the rib portion reinforcing bars 37 are arranged at the rib portions 41 and 42 formed at both ends of the wooden board 21 in the X direction. The arrangement of the reinforcing bars is not limited to these as long as the strength can be ensured in the rib parts 41 and 42 of the concrete part 40.

Next, technical ideas that can be understood from the above embodiment and other examples will be additionally described below.
(a) The floor according to claim 5, characterized in that the void member is fixed on the wooden board and screws arranged between the void members are driven into the wood board. Structure construction method.

A1, A2... Area, 15... Large beam, 20, 70... Floor structure, 21... Wood board, 22... Void member, 23... Screw, 31... Lower end reinforcement, 31a, 31b, 33a, 33b... Rebar, 33... Upper end reinforcement , 37... Rib reinforcing bars, 37a... Rib reinforcing bars, 37b... Rib main reinforcement, 40, 71... Concrete part, 41, 42, 45, 72, 73... Rib part, 50... Formwork, 75... Plane part.

Claims (5)

A floor structure comprising a concrete part made of reinforced concrete and a wooden board placed on the bottom surface,
A void member that forms a rib portion of the concrete portion therebetween can be fixed to the upper surface of the wooden board using the wooden board as a formwork, and
A plurality of screws that integrate the wooden board and the concrete part are embedded in a spaced manner,
The floor structure according to claim 1, wherein the void member is made of a material having a lower specific gravity than the concrete of the concrete portion. 2. The floor structure according to claim 1, wherein the void member is fixed to the upper surface of the wooden board, and the rib portion is formed between the void members. 3. The floor structure according to claim 2, wherein the plurality of void members are spaced apart and provided on the entire surface of the wood board or only on a part of the wood board. The floor structure according to claim 2 or 3, wherein the plurality of void members are provided spaced apart in two directions. A floor structure construction method for constructing a floor structure comprising a concrete part made of reinforced concrete and a wooden board placed on the bottom surface, the method comprising:
A beam type that forms a pair of spaced apart concrete beams that are integrally formed with the concrete part, and the wooden board has a plurality of void members fixed to the upper surface made of a material having a specific gravity lower than that of the concrete of the concrete part. Arrange it so that it spans the top edge of the frame,
Placing reinforcing bars to be buried in the concrete part on the wooden board,
Thereafter, the concrete portion and the concrete beam are formed by pouring concrete using the beam formwork and the wooden board as a formwork, thereby forming the concrete portion and the concrete beam.

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