JPH06229071A - Reinforcing bar and bar arrangement for reinforced concrete structure - Google Patents

Abstract

PURPOSE:To provide an excellent reinforcing effect by bending a flat reinforcing bar having an oval cross section with the flat face set to the inside, and arranging it around a main reinforcement as a shear reinforcing bar. CONSTITUTION:A flat reinforcing bar 1 having an oval cross section is bent and arranged around a main reinforcement 3 with the flat face set to the inside as a shear reinforcing bar. When the flat reinforcing bar 1 is used, the bending diameter D is made smaller than when a circular reinforcing bar 4 is used, and the position of the main reinforcement 3 is arranged near the outside of concrete. The concrete quantity and reinforcing bar quantity are reduced, and the structure weight can be reduced.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforcing bar used in a reinforced concrete structure and a reinforcing bar structure using the reinforcing bar.

[0002]

2. Description of the Related Art Conventionally, as a reinforcing bar used for a reinforced concrete structure, a circular section or a deformed reinforcing bar having an irregular portion on the outer peripheral portion of the circular section has been used.

[0003]

Conventionally, columns, beams, etc. of reinforced concrete structures have shear reinforcements around the main reinforcement, but since the reinforcements have circular cross-section reinforcements, When the reinforcing bar was bent at a right angle, the curvature had to be increased due to the circular cross section.
For this reason, there is a problem that the main reinforcement positions of the columns or beams go inward from the concrete surface. In addition, the shear reinforcement must be closed at its end, and it is not easy to bend it into a hook shape, and the workability is poor.

Further, in a conventional horizontal plate-shaped reinforced concrete structure such as a floor slab, it is necessary to secure a predetermined concrete cover thickness and a distance (effectiveness) from the compression edge of the concrete to the gravity center of the tensile rebar. Since reinforcing bars with a circular cross section were used, there was naturally a limit to reducing the plate thickness.

The present invention has been made in view of the above problems. The purpose of this is to provide a reinforcing bar with excellent reinforcing effects for reinforced concrete structures and efficient processing work, and an excellent reinforcing performance using this reinforcing bar, which can reduce the amount of reinforcing bars and the amount of concrete. To suggest.

[0006]

The reinforcing bar of the reinforced concrete structure according to the invention of claim 1 is characterized in that its cross section is flat.

According to a second aspect of the present invention, in a reinforced concrete structure in which shear reinforcing bars are bent and arranged around a main reinforcing bar, the shear reinforcing bars have a flat cross section and a flat surface is bent inward. It is characterized by

According to a third aspect of the present invention, in the reinforcing bar structure of a horizontal flat plate reinforced concrete structure in which long reinforcing bars are arranged in the horizontal direction, the reinforcing bars are flat in cross section and the flat surface is not horizontal. It is characterized by

[0009]

EXAMPLE FIG. 1 shows a reinforcing bar having a flat cross section according to an example.
(A) is a flat rebar 1-1 having an oval cross section, and has two flat planes 2-1 forming parallel planes and two side surfaces having an arcuate cross section. (B) is a flat bar 1-2 having a trapezoidal cross section, and one flat plane 2-2 and a trapezoidal bent 3
Has two planes. (C) is a flat rebar 1-3 having an octagonal cross section, and has two flat planes 2 formed by parallel planes.
-3 and two side surfaces each of which is formed by three flat surfaces bent in a trapezoidal shape on both sides thereof.

In each of the above-mentioned reinforcing bars, the curvature can be made small by bending with the flat surface inside as compared with a reinforcing bar having a circular cross section with the same cross-sectional area, and at the same time, the bending workability,
It is possible to improve work efficiency and reduce damage to the reinforcing bar. In addition, since the perimeter is increased with the same cross-sectional area, the strength does not change, and an increase in the adhesion strength of concrete can be expected.

2, 3, 4, (a), and (b), each of which is arranged by bending a flat bar 1 having an oval cross section as a shear reinforcing bar around the main bar 3 without bending the flat surface 2 inside. 3 shows a reinforcing bar structure of the embodiment and a comparative example in which a conventional reinforcing bar 4 having a circular cross section is bent and arranged.

The corner portion of the shear reinforcing bar bent by 90 ° (FIG. 2), the hook portion bent by 135 ° (FIG. 3), 180
The bent hook portions (FIG. 4) using the flat bar 1 (a) can have a smaller bending diameter D than those using the circular bar 4 (b). Therefore, if the covering of the concrete 5 from the shear reinforcing bar surface is constant, the position of the main bar 3 can be outside the concrete when the flat bar is used. Therefore, the reinforcing bar works more effectively and can exert a large reinforcing effect.

FIG. 5 (a) is a floor slab of reinforced concrete construction of an embodiment in which flat reinforcing bars 1 are assembled in a lattice shape, and upper reinforcing bars 6-1 and lower reinforcing bars 6-2 are arranged without using the flat surfaces 2-1 as horizontal surfaces. ,
(B) is a lattice-shaped upper end bar 7-1 and lower end bar 7 of the circular reinforcing bar 4.
It is a floor slab of the comparative example using -2.

Assuming that the cover thickness of the predetermined concrete 5 is 8, the concrete compression edge of the floor slab of the embodiment (upper surface of the floor slab)
To the tensile bar (bottom bar) center of gravity (effective strain) 9
Is larger than that of the comparative example, and the slab thickness can be reduced. Even if the floor slab thickness is the same, if a floor duct for wiring electrical equipment or the like is provided in the floor slab, a larger floor duct can be provided because the inner surface distance 10 between the upper end bar and the lower end bar can be increased. be able to. Further, unlike the flat reinforcing bars, the flat reinforcing bars have an advantage that they are hard to rotate and stable even before the upper end reinforcing bars of the floor slab are bound together.

[0015]

The present invention is as described above, and the reinforcing bar can be bent with the flat surface facing inward to reduce the curvature of bending, improving workability and reducing damage to the reinforcing bar. .

The reinforced structure of columns, beams, etc., in which the flat reinforcing bars are bent and arranged as shear reinforcing bars around the main bars, can bring the main bars closer to the concrete surface and can provide a high reinforcing effect. Further, a reinforcing bar structure such as a floor slab in which flat steel bars are horizontally arranged can increase the effective strain of the reinforcing bar, reduce the amount of concrete and the amount of reinforcing bar, and reduce the weight of the structure.

[Brief description of drawings]

1 (a), (b) and (c) are cross-sectional views of a reinforcing bar having a flat cross section according to the present invention.

2 (a) and 2 (b) are cross-sectional views of a reinforced concrete corner portion having flat reinforcing bars and circular reinforcing bars as shear reinforcing bars.

3 (a) and 3 (b) are cross-sectional views of a hook portion of reinforced concrete having flat reinforcing bars and circular reinforcing bars as shear reinforcement bars bent at 135 °.

4 (a) and 4 (b) are cross-sectional views of a hook portion of a reinforced concrete which is made of flat reinforcing bars and circular reinforcing bars as shear reinforcing bars and is bent by 180 °.

5 (a) and 5 (b) are cross-sectional views of a floor slab reinforced with flat reinforcing bars and circular reinforcing bars.

[Explanation of symbols]

1 ... flat bar, 2 ... plane, 3 ... main bar, 4
... Reinforcing rods with circular cross section, 5 ... Concrete, 6-
1, 7-1 ... upper end streak, 6-2, 7-2 ... lower end streak, 8 ... cover thickness, 9 ... effective cause, 10 ...
-Inner spacing between the upper and lower streaks.

Claims (3)

[Claims] 1. A reinforcing bar of a reinforced concrete structure having a flat cross section. 2. A reinforcing structure of a reinforced concrete structure, comprising shear reinforcing bars bent and arranged around a main bar,
Shear reinforcement is a reinforced concrete structure that has a flat cross section and is formed by bending without a flat surface inside. 3. A reinforcing structure of a horizontal plate-shaped reinforced concrete structure in which long reinforcing bars are arranged in the horizontal direction, wherein the reinforcing bars are flat in cross section and the flat surfaces are not horizontal surfaces. Reinforcement structure of reinforced concrete structure.