JPS606084Y2 - Reinforcement structure for corners of reinforced concrete wall openings - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a reinforcement structure for the corner portion of an opening in a reinforced concrete wall.

When a reinforced concrete wall 2 having an opening 1 as shown in FIG. 1 is subjected to shearing force during an earthquake, cracks 3 will appear at the corners of the opening 1. 4 is arranged to suppress the occurrence of the crack 3 and prevent the crack 3 from expanding.

In the figure, 5 is a horizontal edge reinforcing reinforcing bar, and 6 is a vertical edge reinforcing bar.

However, since the diagonal reinforcing reinforcing bars 4 require a predetermined anchoring length, their total length reaches at least 5 mm in diameter, and the diagonal reinforcement work is complicated, making it difficult to maintain a fixed position and fixed angle. There was a drawback.

Alternatively, as shown in FIG. 3, one corner of the vertical and horizontal welded wire mesh 7 is cut out, and the welded wire mesh 7 is arranged so that the cutout portion of the welded wire mesh 7 matches the corner of the opening 1. However, since the direction of the wire of the wire mesh 7 is approximately 45 degrees to the direction in which the crack 3 occurs, the growth of the crack 3 is prevented. The effect of suppressing expansion is small.

The present invention was developed in view of the above circumstances, and is designed to prevent cracks from occurring at the corners of openings in reinforced concrete walls, and to suppress the growth and expansion of cracks even if they occur. The purpose is to provide a reinforcing structure.

The reinforcing structure of the corner of a reinforced concrete type opening according to the present invention is as shown in FIG. The cross-welded wire mesh 8 is arranged so that the notch 9 of the wire mesh 8 matches the corner of the opening 1 of the reinforced concrete wall 2 as shown in FIG. 5, and the corner of the opening 1 is reinforced. It consists of

In the reinforced concrete wall opening corner reinforcement structure of the present invention, the direction of the wire rods of the oblique welded wire mesh 8 disposed at the opening corner is approximately 45 degrees with respect to the sides of the opening 1, so that the opening corner is Since it is approximately perpendicular to the direction in which the crack 3 (see Fig. 1) occurs at the corner, it is possible to prevent the occurrence of the crack 3, and even if the crack 3 occurs, the growth and expansion of the crack 3 can be suppressed. can.

Moreover, since the reinforcing effect extends over a wider range compared to the reinforcement by the conventional diagonal reinforcing reinforcing bars 4 shown in FIG. 2, the effect of preventing cracks at the corner of the opening is greater.

In general, the amount of shear deformation and the amount of deformation due to expansion and contraction in the 45° direction are:
It has been clarified both experimentally and theoretically that the amount of deformation in diagonal reinforcement in the 45° direction with the same amount of reinforcement is half that of reinforcement in the vertical and horizontal directions. Tamoto Architectural Institute Papers No. 48 (March 1952) ``Analysis of shear resistance after cracking in reinforced concrete walls using orthotropic elastic plate theory'' and others].

Therefore, under the same conditions, the crack width of the diagonal crack 3 at the corner of the opening is half as large when diagonal welded wire mesh 8 is used as compared to when ordinary vertical and horizontal welded wire mesh 7 is used. The crack width can be suppressed to 1.

In addition, as shown in Fig. 6 a and b, ordinary vertical and horizontal welded wire meshes 7 are
In order to achieve the same crack prevention effect with the reinforcing structure of the present invention by rotating it by 5 degrees and using it for reinforcement, a large vertical and horizontal welded wire mesh 7 is required as shown in Fig. 6a, which is uneconomical. In addition, when a rectangular vertical and horizontal welded wire mesh 7 is used as shown in Figure 6, it is difficult to maintain it at a fixed position and at a fixed angle, making it unreliable and no reinforcing effect can be expected.

However, the reinforcing structure of the corner of an opening in a reinforced concrete wall using the oblique welded wire mesh 8 manufactured by, for example, the "oblique welded wire mesh manufacturing apparatus" of JP-A No. 54-77773, is a wire mesh with a small area. 8 can effectively prevent cracks and is extremely economical.

In addition, in the reinforcing structure of the present invention, even if the wire mesh 8 has a short fixing length, it can be firmly fixed to the corner of the opening and can withstand the wire rod being pulled out, so a relatively small wire mesh 8 can have a sufficient reinforcing effect.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the occurrence and growth of cracks at the corners of openings in reinforced concrete walls, and Figures 2 and 3 are diagrams showing conventional means for suppressing the occurrence and growth of cracks at the corners of openings in reinforced concrete walls. , FIG. 4 is a diagram showing an oblique welded wire mesh used in the reinforcement structure for the corner of an opening in a reinforced concrete wall according to the invention, FIG. Figures 6a and 6b are diagrams showing means for suppressing the generation and growth of cracks at the corners of openings in reinforced concrete walls using ordinary welded wire mesh. 1...Opening, 2...Reinforced concrete wall, 3...Crack, 4...Diagonal reinforcing bar, 5...Horizontal edge reinforcement Reinforcing bars, 6... Vertical edge reinforcing bars, 7... Vertical and horizontal welded wire mesh, 8...
...Oblique welded wire mesh, 9...Notch part.

Claims (1)

[Scope of utility model registration request] Reinforced concrete made by cutting out one corner of a substantially square oblique welded wire mesh, disposing the oblique welded wire mesh so that the notch matches the corner of an opening in a reinforced concrete wall, and reinforcing the corner of the opening. Reinforcement structure for the corners of wall openings.