JP5417807B2 - Reinforcing bar holding structure, reinforcing bar holding method, reinforcing method for reinforced concrete structure - Google Patents

Description

  The present invention relates to a reinforcing method in which an existing reinforced concrete structure is reinforced by arranging reinforcing bars along a side surface or a lower surface and spraying shotcrete, and a reinforcing bar holding method used in this method.

  Since the road slab is subjected to repeated loads from the automobile passing through the upper part, it may be necessary to reinforce the cracks on the lower surface of the concrete. When reinforcing such a floor slab, it is desirable not to obstruct the passage of the automobile on the floor slab. Therefore, conventionally, a method of placing a steel plate along the lower surface of the floor slab and fixing the steel plate with an anchor and an adhesive, or a method of attaching high strength fibers such as carbon fibers to the lower surface of the floor slab with an adhesive Is used.

  However, in the method of attaching a steel plate to the lower surface of the floor slab with an anchor and an adhesive, the weight of the steel plate is large, so a heavy machine for lifting is required, and the work of arranging the steel plates is very laborious. Further, in the method of bonding high-strength fibers, the high-strength fibers have a lower rigidity than a concrete frame, so that a sufficient reinforcing effect cannot be obtained.

Therefore, for example, in Patent Document 1, a part of a portion corresponding to a reinforcing portion of a concrete lower surface constituting a floor slab is removed to expose the reinforcing bar, and the reinforcing reinforcing bar is coupled to the exposed reinforcing bar using a connector, A method for reinforcing a floor slab by spraying mortar or concrete on the reinforcing portion is described. According to this method, since a heavy lifting machine or the like is not required, the reinforcing bars can be arranged without taking time and the reinforcing bars constituting the floor slab and the reinforcing reinforcing bars are integrated. A sufficient reinforcing effect can be obtained.
JP 2002-167777 A

  However, in the method described in Patent Document 1, it is necessary to remove the lower part of the concrete constituting the floor slab, and at this time, the strength of the floor slab is reduced. For this reason, there exists a problem that it is not suitable for construction in the state where a car passed through the upper part.

  The present invention has been made in view of the above problems, and an object thereof is to reinforce a reinforced concrete structure without damaging the strength of the floor slab during construction.

The reinforcing bar holding structure of the present invention is a holding structure for holding a reinforcing bar along the lower surface or side surface of a reinforced concrete structure, and the anchor bolts placed on the lower surface or side surface of the structure, A nut that is screwed to the anchor bolt and holds the reinforcing bar arranged along the lower surface or the side surface of the structure via a contact member that contacts the surface of the reinforcing bar opposite to the structure. The abutting member comprises a rod-like member attached to the nut so as to extend laterally, and the rod-like member abuts against the reinforcing bar only from the side opposite to the structure. to.

Further, a method of holding the rebar of the present invention is to Da設the A Nkaboruto the lower surface or side of the structure of reinforced concrete, rebar disposed along the lower surface or side of the structure, the nut on the anchor bolt Reinforcing bar holding that holds the reinforcing bar along the lower surface or side surface of the structure via a contact member that contacts the surface of the reinforcing bar opposite to the structure by screwing. The contact member is a rod-shaped member attached to the nut so as to extend laterally, and the rod-shaped member is brought into contact with the reinforcing bar only from the side opposite to the structure. It is characterized by making it.

The reinforcing method of the reinforced concrete structure of the present invention is to Da設anchor bolts under surface or side of the structure of reinforced concrete, rebar disposed along the lower surface or side of the structure, the By screwing a nut onto an anchor bolt, the reinforcing bar is held via a contact member that contacts the surface of the reinforcing bar opposite to the structure, and sprayed concrete is applied to the lower surface or side surface of the structure. A method of reinforcing a reinforced concrete structure to be sprayed , wherein the abutting member includes a rod-like member attached to the nut so as to extend laterally, and the rod-like member is connected to the reinforcing bar with the structure. It is characterized by contacting only from the opposite side to the object . Here, the structure may be a floor slab of a road bridge.

  According to the present invention, it is possible to hold a reinforcing bar by placing an anchor bolt on the lower surface of a concrete structure and tightening a nut so as to hold the reinforcing bar to the anchor bolt via a contact member. It is possible to prevent the strength of the concrete structure from being lowered during construction.

Hereinafter, an embodiment of a method for reinforcing a reinforced concrete structure according to the present invention will be described with reference to the drawings, taking as an example the case of reinforcing a floor slab of a road bridge.
FIG. 1 is a vertical sectional view showing a floor slab 20 of a road bridge 10 to be reinforced by the reinforcing method of the present embodiment. In the road bridge 10, a floor slab 20 in which reinforcing bars 21 and 22 are embedded in a lattice pattern in plan view in the vicinity of the upper and lower surfaces of a plate-like concrete member 23 is supported by a girder 30 made of H-shaped steel at a predetermined interval. Being done. Since the automobile passing through the road bridge 10 passes over the floor slab 20, a load is repeatedly applied to the floor slab 20. For this reason, the concrete 23 which comprises the floor slab 20 is cracked, or the reinforcing bars 21 and 22 are deteriorated due to moisture or the like entering from the crack. The reinforcing method of the present embodiment is a method of reinforcing the floor slab 20 thus deteriorated from the lower surface side of the floor slab 20 in a state where an automobile can pass on the upper road surface.

  FIG. 2 is a plan view showing a mounting nut 40 used in the reinforcing method of the present embodiment. As shown in the figure, the mounting nut 40 is formed by attaching a rod-shaped steel material 42 at a position where the side surface of the hexagonal nut 41 faces.

  Hereinafter, the reinforcing method of the present embodiment will be described with reference to FIGS. 3A to 3D. 3A, FIG. 3B (A), FIG. 3C (A), and FIG. 3D are vertical sectional views of the lower portion of the floor slab 20 in the progress of the reinforcement work. 3B and 3C, (B) is a BB ′ arrow view in (A).

  First, as shown in FIG. 3A, anchor bolts 60 are driven on the lower surface of the floor slab 20 at appropriate intervals in the vertical and horizontal directions. The interval for placing the anchor bolt 60 is set so that a shearing force can be transmitted via the anchor bolt 60 between the sprayed concrete sprayed on the lower surface of the floor slab 20 described later and the floor slab 20. That's fine. Moreover, it is good to drive many anchor bolts 60 near the side part of the floor slab 20 compared with the center part.

  In the present embodiment, the anchor bolt 60 is driven on the lower surface of the floor slab 20, and only the compressive stress acts on the lower surface of the floor slab 20, so that even if the anchor bolt 60 is driven, the floor slab is placed. The strength of 20 is not affected.

  Next, as shown in FIG. 3B, mesh bars 50 in which reinforcing bars 51 are assembled in a lattice shape on the lower surface of the floor slab 20 are arranged along the lower surface of the floor slab 20.

  Next, as shown in FIG. 3C, the mounting nut 40 is screwed into the anchor bolt 60, and the mounting nut 40 is attached until the upper surface of the steel material 42 of the mounting nut 40 comes into contact with the lower surface of the reinforcing bar 51 constituting the mesh bar 50. Tighten 40. Thereby, the mesh line 50 is held via the steel material 42 by the hexagon nut 41 screwed into the anchor bolt 60. As shown in FIG. 4, in the case where a bent portion 52 is formed at the end of the reinforcing bar 51 constituting the mesh bar 50, the anchor bolt 60 is positioned within the bent portion 52. The mounting nut 40 may be tightened so that the steel members 42 on both sides of the mounting nut 40 abut against the bent portion 52, respectively.

Next, as shown in FIG. 3D, spray concrete 70 is sprayed on the lower surface of the floor slab 20 to a thickness of about 3 to 4 cm. In this embodiment, since the mounting nut 40 in which the steel material 42 is attached to the side surface of the hexagon nut 41 is used, the spray concrete 70 may be sprayed so that the hexagon nut 41 is covered. The thickness can be reduced.
In addition, as shotcrete 70, it is good to use polymer concrete with high durability compared with normal concrete. In this embodiment, since the thickness of the shotcrete 70 is thin, the cover thickness of the concrete is reduced. Even in such a case, the reinforcing bar 51 can be protected by using polymer concrete.
Then, as the shotcrete 70 is cured, the reinforcing structure 100 of the floor slab 20 is completed as shown in FIG.

  According to the reinforcing structure 100 of the floor slab 20 constructed as described above, the shear force is transmitted between the floor slab 20 and the mesh streak 50 via the anchor bolt 60. The concrete 70 is integrated with the floor slab 20 and resists a bending load acting on the floor slab 20. Thereby, the bending strength of the floor slab 20 is improved.

  As described above, according to the present embodiment, the floor slab 20 is configured to fix the mesh bars 50 by screwing the mounting nuts 40 to the anchor bolts 60 placed on the lower surface of the floor slab 20. The construction can be performed without removing a part of the concrete 23, and the construction can be performed safely even when the automobile passes through the floor slab 20.

  In addition, the mesh bars 50 can be easily fixed by screwing the mounting nuts 40 to the anchor bolts 60 placed on the lower surface of the floor slab 20, and the shot concrete 70 is used. There is no need to install a formwork or the like, and the workability can be improved.

Further, since the mesh bars 50 are measured in comparison with the steel plate, the workability of the installation work on the lower surface of the floor slab 20 is good.
Further, since reinforcement is performed by arranging mesh bars 50 on the lower surface of the floor slab 20 and spraying shotcrete 70, higher strength can be obtained as compared with the method of attaching high-strength fibers.

In the present embodiment, the mesh bars 50 are fixed by the mounting nut 40 in which the bar-shaped steel material 42 is attached to the side surface of the hex nut 41. However, the present invention is not limited to this, and the hex nut as shown in FIG. 41 and the steel plate 142 provided with a hole at a position corresponding to the hole of the hexagon nut 41 may be used to hold the reinforcing bar by the steel plate 142.
Furthermore, the steel plate 142 and the hex nut 41 in the mounting member 140 are not necessarily integrated. That is, the steel material 42 or the steel plate 142 may be configured to be pressed against the mesh reinforcement 50 by tightening the hexagon nut 41 separate from the steel material 42 or the steel plate 142 to the anchor bolt 60.
Moreover, although this embodiment demonstrated the case where the attachment nut 40 to which the steel material 42 was attached to the both sides of the hexagon nut 41 was used, not only this but the hexagon nut 41 as shown to FIG. 7 (A) is shown. A mounting nut 40A in which the steel material 42 is attached to one side of the same, a mounting nut 40B in which the steel material 42 is attached to the hexagonal nut 41 in a plan view as shown in FIG. As shown in (C), a mounting nut 40C in which a steel material 42 is attached to the opposing surface of the hex nut 41 may be used. In short, the steel material 42 is attached so as to protrude sideways from the hex nut 41. Any mounting nut can be used.

  Moreover, although this embodiment demonstrated the case where the lower surface of the floor slab 20 of the road bridge 10 was reinforced, it is not restricted to this, It applies also when reinforcing concrete structures, such as a tunnel, from the side or lower surface side. be able to. In addition, the lower surface or side surface of the present invention includes a downward inclined surface.

It is a vertical sectional view which shows the floor slab of the road bridge used as the object of reinforcement by the reinforcement method of this embodiment. It is a top view which shows the nut for attachment used for the reinforcement method of this embodiment. It is FIG. (1) for demonstrating the reinforcement method of this embodiment, and is a vertical sectional view of the lower part of a floor slab. It is a figure (the 2) for demonstrating the reinforcement method of this embodiment, (A) is a vertical sectional view of the lower part of a floor slab, (B) is a BB 'arrow line view in (A). It is a figure (the 3) for demonstrating the reinforcement method of this embodiment, (A) is a vertical sectional view of the lower part of a floor slab, (B) is a BB 'arrow line view in (A). It is a figure (the 4) for demonstrating the reinforcement method of this embodiment, and is a vertical sectional view of the lower part of a floor slab. It is a figure which shows a mode that the attachment nut was attached so that it might contact | abut to the bending part formed in the edge part of the reinforcing bar which comprises a mesh reinforcement. It is a vertical sectional view showing a floor slab that has been reinforced. It is a figure which shows the attachment member with which the hexagon nut and the steel plate were united. (A) shows a mounting nut attached so that the steel material protrudes from one side of the hex nut, and (B) shows a mounting nut attached so that the steel material protrudes in a cross shape in plan view from the hex nut. (C) is a figure which shows the nut for attachment by which the steel materials were attached to the surface which a hexagon nut opposes.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Road bridge 20 Floor slab 21, 22 Reinforcement 23 Concrete member 30 Girder material 40 Installation nut 41 Nut 42 Steel material 50 Mesh reinforcement 51 Reinforcement 52 Bending part 60 Anchor bolt 70 Shotcrete 100 Reinforcement structure 140 Attachment member 142 Steel plate

Claims (4)

A holding structure for holding a reinforcing bar along the bottom or side of a reinforced concrete structure,
Anchor bolts placed on the lower surface or side surface of the structure;
A nut that is screwed to the anchor bolt, holding a reinforcing bar arranged along the lower surface or side surface of the structure via a contact member that contacts the surface of the reinforcing bar opposite to the structure;
Equipped with a,
The contact member is formed of a rod-shaped member attached to the nut so as to extend sideways, and the rod-shaped member contacts the reinforcing bar only from the side opposite to the structure. Reinforcing bar retention structure. And Da設the A Nkaboruto the lower surface or side of the structure of reinforced concrete,
Place the reinforcing bars along the bottom or side of the structure,
By screwing a nut into the anchor bolt, the reinforcing bar is placed along the lower surface or side surface of the structure via a contact member that contacts the surface of the reinforcing bar opposite to the structure. A method for holding a reinforcing bar,
The contact member comprises a rod-like member attached to the nut so as to extend sideways, and the rod-like member is brought into contact with the reinforcing bar only from the side opposite to the structure. Reinforcing bar holding method. And Da設anchor bolts under surface or side of the structure of reinforced concrete,
Place the reinforcing bars along the bottom or side of the structure,
By screwing a nut into the anchor bolt, the reinforcing bar is held via a contact member that contacts the surface of the reinforcing bar opposite to the structure,
A method for reinforcing a reinforced concrete structure in which shotcrete is sprayed on the lower surface or side surface of the structure,
The contact member comprises a rod-like member attached to the nut so as to extend sideways, and the rod-like member is brought into contact with the reinforcing bar only from the side opposite to the structure. To reinforce reinforced concrete structures. . A method for reinforcing a reinforced concrete structure according to claim 3 ,
The method for reinforcing a reinforced concrete structure, wherein the structure is a floor slab of a road bridge.

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