Flat Plate Structure

Abstract

To provide a flat plate structure which can secure rigidity of a part such as surroundings of an opening in which rigidity of a floor slab is required.SOLUTION: A flat plate structure 10 including a beam-less floor slab 16 directly supported by at least one of a plurality of columns 12 and walls 14 comprises: an upper member 18 comprising reinforced concrete constituting an upper side part of the floor slab 16; a lower member 20 comprising steel plate concrete constituting a lower side part of the floor slab 16; and a beam-type reinforcing member 24 provided in the floor slab 16.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a flat plate structure that constitutes a floor slab. [Background technology]

[0002] Conventionally, the substructure of nuclear power plant buildings (reactor buildings, turbine buildings, etc.) has mainly been an RC (reinforced concrete) frame structure as shown in Fig. 4 (see, for example, Patent Document 1). Fig. 5(1) is a cross-sectional view of the main part of an RC frame structure applied to nuclear power plant buildings. As shown in this figure, this structure is composed of RC beams 1 and RC floor 2, and temporary steel beams 3, floor formwork 4, etc. are placed below the RC floor 2. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-13621 Summary of the Invention [Problem to be solved by the invention]

[0004] The inventors have studied a structure in which the above-mentioned RC frame structure is changed to a flat plate structure in which a flat RC floor slab without beams is directly supported by columns and walls, and the lower half of this floor slab is changed to a steel concrete (SC) structure (hereinafter referred to as SC structure). An example of the structure after the change is shown in Figure 5 (2). As shown in this figure, the changed structure consists of a flat floor slab 5, with the upper part of the floor slab 5 made of RC and the lower part made of SC, with the bottom and sides of the concrete covered with steel plates 6. By adopting such a structure, the following effects (1) to (3) can be obtained.

[0005] (1) In conventional RC frame structures, RC girders and beams are placed on the floor, but the piping installed under the floor has to be passed under the beams, which narrows the space for the piping and restricts its freedom (see Figure 5(1)). However, by using a flat plate structure and eliminating the beams, more space is created under the floor (see Figure 5(2)), which allows the floor height to be reduced.

[0006] (2) In the construction of nuclear power plants, before the floor slab is constructed, it is necessary to transport equipment and piping materials into the room below the floor, which means that shoring to support the floor formwork cannot be installed on the floors below. For this reason, temporary steel beams were previously installed from wall to wall under the floor formwork, which put pressure on the piping space. However, by changing the floor to a SC structure, the floor bottom reinforcement is eliminated, so these temporary steel beams can be embedded within the floor slab, creating more space under the floor and allowing the floor height to be reduced.

[0007] (3) In the construction of nuclear power plants, there is generally a strong demand for shortening the construction period, but with the conventional structure consisting of reinforced concrete girders, sub-girders, and floor slabs, the construction period could not be shortened due to the complicated construction procedures for the temporary steel beams, formwork, and reinforcement under the floor. However, by using a flat plate structured SC floor, the construction procedures can be simplified and the construction period can be shortened.

[0008] However, when adopting a structure like the one shown in Figure 5(2) above, the floor needs to be rigid to suppress the vibration of the equipment installed on the floor, and the natural frequency needs to be 20 Hz or more, but there is a problem in that there are parts, such as around large floor openings, that do not meet this frequency requirement. For this reason, it has been necessary to ensure rigidity in such parts so that the frequency requirement can be met.

[0009] The present invention has been made in consideration of the above, and aims to provide a flat plate structure that can ensure rigidity in areas where rigidity is required in the floor slab, such as around openings. [Means for solving the problem]

[0010] In order to solve the above-mentioned problems and achieve the object, the flat plate structure of the present invention is a flat plate structure comprising a beam-less floor slab directly supported by at least one of a plurality of columns or walls, and is characterized by comprising an upper member made of reinforced concrete that constitutes the upper part of the floor slab, a lower member made of steel plate concrete that constitutes the lower part of the floor slab, and a beam-type reinforcing member provided on the floor slab.

[0011] Another flat plate structure according to the present invention is characterized in that, in the above-mentioned invention, the beam-shaped reinforcing member is made of steel plate concrete having beam-shaped concrete and a steel plate placed on the surface of the concrete.

[0012] Furthermore, another flat plate structure according to the present invention is characterized in that, in the above-mentioned invention, the beam-shaped reinforcing member is composed of steel plate concrete having beam-shaped concrete, H-shaped steel or steel plates arranged on the sides of the concrete, and steel plates arranged on the bottom surface of the concrete.

[0013] Another flat plate structure according to the present invention is characterized in that, in the above-mentioned invention, the beam-shaped reinforcing member is connected to the lower part of the upper member of the floor slab and to the side of the lower member, protruding downward from the floor slab. [Effects of the Invention]

[0014] The flat plate structure of the present invention is a flat plate structure comprising a beam-less floor slab directly supported by at least one of a plurality of columns or walls, and is provided with an upper member made of reinforced concrete that forms the upper part of the floor slab, a lower member made of steel plate concrete that forms the lower part of the floor slab, and a beam-type reinforcing member provided on the floor slab.Therefore, by providing the beam-type reinforcing member, it is possible to ensure rigidity in parts of the floor slab where rigidity is required, such as around openings.

[0015] Furthermore, in another flat plate structure according to the present invention, the beam-shaped reinforcing member is made of steel plate concrete, which has beam-shaped concrete and steel plates placed on the surface of the concrete, so it is possible to reduce the amount of reinforcing steel inside the concrete and reduce the amount of reinforcing bar arrangement work, thereby achieving the effects of reducing construction costs and shortening the construction period.

[0016] In addition, according to another flat plate structure of the present invention, the beam-shaped reinforcing member is composed of steel plate concrete having beam-shaped concrete, H-shaped steel or steel plates arranged on the sides of the concrete, and steel plates arranged on the bottom surface of the concrete, which makes it possible to reduce the amount of steel reinforcement inside the concrete and reduce the amount of reinforcement work, and also has the effect of further improving the rigidity of the reinforcing member.

[0017] In addition, according to another flat plate structure of the present invention, the beam-shaped reinforcing member is connected to the lower part of the upper member of the floor slab and to the side of the lower member, protruding downward from the floor slab, which makes it easier to integrate the reinforcing member with the floor slab and has the effect of improving workability on site. [Brief explanation of the drawings]

[0018] [Figure 1] FIG. 1 is a cross-sectional plan view showing an embodiment of a flat plate structure according to the present invention. [Figure 2] FIG. 2 is a cross-sectional side view taken along line AA in FIG. [Figure 3] FIG. 3 is a side cross-sectional view showing another embodiment of a flat plate structure according to the present invention. [Figure 4] FIG. 4 is a side cross-sectional view showing an example of the structure of a conventional nuclear power plant building (in the case of a reactor building). [Figure 5] Figure 5 shows a comparison between a conventional RC frame structure, a flat plate structure, and a SC floor. DETAILED DESCRIPTION OF THE INVENTION

[0019] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A flat plate structure according to an embodiment of the present invention will be described in detail below with reference to the accompanying drawings. However, the present invention is not limited to these embodiments.

[0020] As shown in Figures 1 and 2, a flat plate structure 10 according to an embodiment of the present invention is applied to, for example, the substructure of a nuclear power plant building and includes a beam-less floor slab 16 directly supported by columns 12 and walls 14. The flat plate structure 10 includes an upper member 18 made of reinforced concrete that forms the upper portion of the floor slab 16, a lower member 20 made of steel plate concrete that forms the lower portion of the floor slab 16, and beam-type reinforcing members 24 provided along the periphery of an opening 22. Reinforcing bars 28 are arranged within the concrete 26 of the upper member 18. H-shaped steel beams 30 and reinforcing bars 28 are arranged horizontally at intervals at the bottom of the lower member 20, and a steel plate 32 is arranged on the bottom surface of the lower member 20. Studs 34 protrude from the inner surface of the steel plate 32 and are embedded in the concrete 26.

[0021] As shown in Figure 1, the opening 22 is a rectangular opening in plan view provided in the floor slab 16. The opening 22 is positioned away from the rear wall 14 and the right wall 14. A column 12 is located at the front corner on the left side of the opening 22. The area around the opening 22 is a part of the floor slab 16 that requires rigidity.

[0022] As shown in Figure 2, the reinforcing member 24 is made of steel plate concrete (SC structure) having a beam-shaped concrete 36, H-shaped steel 38 arranged on both sides of the concrete 36, and a steel plate 40 arranged on the bottom of the concrete 36. The beam-shaped concrete 36 is connected to the bottom of the upper member 18 of the floor slab 16 and to the side of the lower member 20, protruding downward from the floor slab 16. Hoop-shaped reinforcing bars 42 and rod-shaped reinforcing bars 44 are arranged inside the beam-shaped concrete 36.

[0023] The web 46 of the H-shaped steel 38 is placed on the side of the concrete 36, and one upper surface of the upper flange 48 is flush with the bottom surface of the lower member 20 of the floor slab 16 and is connected to the steel plate 32 of the lower member 20. The other end of the upper flange 48 is embedded in the beam-shaped concrete 36. A steel plate 40 is connected to the upper surface of the lower flange 50 of the H-shaped steel 38. Studs 52 protrude from the inner surface of the web 46 and the upper surface of the upper flange 48, and the studs 52 are embedded in the concrete 36. Using this configuration can improve the rigidity of the reinforcing member 24. The H-shaped steel 38 and steel plate 40 are used as a concrete formwork.

[0024] 1, the reinforcing members 24 are arranged along the left and front edges of the opening 22. The reinforcing member 24 along the left edge of the opening 22 is arranged in the front-to-rear direction from the rear wall 14 toward the pillar 12. The reinforcing member 24 along the front edge of the opening 22 is arranged in the left-to-right direction from the right wall 14 toward the pillar 12. Note that the arrangement positions of the reinforcing members of the present invention are not limited to this, and for example, reinforcing members 24 may be further provided along the rear and right edges of the opening 22.

[0025] According to this embodiment, by providing beam-type reinforcing members 24 in areas where rigidity is required in the floor slab 16, such as around the opening 22, the rigidity of these areas can be ensured. In this way, most of the floors of the building can be made into SC structure floors with flat plate structures that are space-saving and easy to construct, and the effects of (1) to (3) above can reduce the construction cost and construction period of the nuclear power plant building.

[0026] Furthermore, by using a SC structure instead of an RC structure for the reinforcing member 24, the amount of reinforcing bars inside the reinforcing member 24 can be minimized, and the amount of on-site work can be reduced, thereby shortening the construction period.

[0027] If the reinforcing member 24 is constructed with an RC structure, a large amount of reinforcing bars, as well as formwork for the sides and bottom of the reinforcing member 24, and shoring are required inside the reinforcing member 24. In contrast, if the reinforcing member 24 is constructed with an SC structure as in this embodiment, steel materials are placed on the sides and bottom of the reinforcing member 24, which allows for a significant reduction in the amount of reinforcing bars inside the reinforcing member 24. In addition, formwork and shoring for the reinforcing member 24 are no longer necessary, making construction easier. It is possible to reduce the amount of reinforcing bars inside the concrete and reduce the amount of reinforcing bar arrangement work, which reduces construction costs and shortens the construction period.

[0028] Furthermore, because the lower member 20 of the floor slab 16 around the reinforcing member 24 has the same SC structure as the reinforcing member 24, the steel parts of the reinforcing member 24 and the lower member 20 of the floor slab 16 can be assembled together in a factory and then installed all at once on the construction site using a crane or the like, thereby streamlining construction. This makes it easy to integrate the reinforcing member 24 and the floor slab 16, improving on-site workability.

[0029] The reinforcing member of the present invention is not limited to the structure shown in FIG. 2 , and may have a structure such as that shown in FIG. 3 . The reinforcing member 24A of FIG. 3 uses a steel plate 54 surrounding the concrete 36 on at least three sides instead of the opposing H-shaped steel beams 38 and the steel plate 40 spanning between them in the reinforcing member 24 of FIG. 2 . The steel plate 54 has a U-shaped cross section with at least an opening at the top. In the example of FIG. 3 , a single steel plate is used, which has a bottom surface 54A, two opposing side surfaces 54B extending vertically from both ends of the bottom surface 54A, and an upper surface 54C extending horizontally inward from the upper ends of the side surfaces 54B. The upper opening is narrowed by bending the steel plate. A restricting member 56 may be provided between the side surface 54B of the steel plate 54 and the steel plate 32 of the lower member 20 to maintain a predetermined relative position between them.

[0030] Studs 52 protrude from the inner sides of the bottom surface 54A and side surfaces 54B of the steel plate 54, and the studs 52 are embedded in the concrete 36. The upper portions of the side surfaces 54B and the top surface 54C of the steel plate 54 are disposed within the floor slab 16. Studs 52A protrude above and below the top surface 54C. Reinforcing bars 28 extending horizontally are disposed between the lower member 20 of the floor slab 16 and the concrete 36. The reinforcing bars 28 are disposed so as to penetrate horizontally the upper portions of the side surfaces 54B of the steel plate 54.

[0031] As described above, the flat plate structure of the present invention is a flat plate structure comprising a beam-less floor slab directly supported by at least one of a plurality of columns or walls, and is equipped with an upper member made of reinforced concrete that forms the upper part of the floor slab, a lower member made of steel plate concrete that forms the lower part of the floor slab, and a beam-type reinforcing member provided on the floor slab.By providing the beam-type reinforcing member, it is possible to ensure rigidity in parts of the floor slab where rigidity is required, such as around openings.

[0032] Furthermore, in another flat plate structure according to the present invention, the beam-shaped reinforcing member is made of steel plate concrete, which has beam-shaped concrete and steel plates placed on the surface of the concrete, so it is possible to reduce the amount of reinforcing steel inside the concrete and reduce the amount of reinforcing bar arrangement work, thereby reducing construction costs and shortening the construction period.

[0033] In addition, according to another flat plate structure of the present invention, the beam-shaped reinforcing member is composed of steel plate concrete having beam-shaped concrete, H-shaped steel or steel plates placed on the sides of the concrete, and steel plates placed on the bottom of the concrete, so that it is possible to reduce the amount of steel reinforcement inside the concrete, thereby reducing the amount of reinforcement work, and further improving the rigidity of the reinforcing member.

[0034] In addition, according to another flat plate structure of the present invention, the beam-shaped reinforcing member is connected to the lower part of the upper member of the floor slab and to the side of the lower member, protruding downward from the floor slab, making it easier to integrate the reinforcing member with the floor slab and improving on-site workability. [Industrial Applicability]

[0035] As described above, the flat plate structure of the present invention is useful for the substructure of nuclear power plant buildings (reactor buildings, turbine buildings, etc.), and is particularly suitable for ensuring rigidity in areas where rigidity is required in the floor slab, such as around openings. [Explanation of symbols]

[0036] 10 Flat plate structure 12 pillars 14 Wall 16 Floor slab 18 Upper member 20 Lower member 22 Opening 24 Reinforcement member 26,36 Concrete 28, 42, 44 Reinforced concrete 30,38 H type steel 32,40 steel plate 34,52 studs 46 Web 48 Upper flange 50 Lower flange

Claims

[Claim 1] A flat plate structure comprising a beamless floor slab directly supported by at least one of a plurality of columns or walls, An upper member made of reinforced concrete that constitutes the upper part of the floor slab, a lower member made of steel plate concrete that constitutes the lower part of the floor slab, and a beam-type reinforcing member provided on the floor slab along the periphery of the opening in the floor slab, The beam-shaped reinforcing member is composed of steel plate concrete having beam-shaped concrete, H-shaped steel or steel plates placed on the sides of the concrete, and steel plates placed on the bottom of the concrete, and is connected to the lower part of the upper member of the floor slab and the side of the lower member, protruding downward from the floor slab.This is a flat plate structure characterized by the above.

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