JPS6030766A - Method and structure for controlling crack in concrete wall opening part - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method and apparatus for controlling cracks in openings in concrete walls.

Generally, cracks occur in openings in concrete walls due to drying shrinkage of the concrete, and the amount of shrinkage is particularly concentrated at the corners, making it easy for cracks to occur as shown in FIG.

That is, the free shrinkage strain of the Funklinote wall is generally 5×10
It has been found through actual measurements that it is about -4. For example, at the corner of a wall with a length of 3,000 mm,
mX]/2X 5 XIO-''=0.75 mm.

On the other hand, the above-mentioned cracks are also caused by the restraint of columns and beams around the wall, and the degree of restraint is generally 0.2 to 0.
It is said to be 6. Therefore, the opening is 0.75mm
．． There is always a shrinkage of about 2-0.6=0.15-0.45+nm, which causes cracks.

Conventionally, a method of arranging reinforcing bars at the corners of openings has been adopted to prevent cracks, but if the reinforcing bars are not placed accurately, the cracks tend to widen; No matter what measures you take, this type of crack can be prevented 100%.
It has become impossible to prevent it.

Research to date has also revealed that water leaks when the crack width exceeds 0.1 mm, and that reinforcing bars inside concrete walls rust when the crack width exceeds 0.2 to 0.3 mm.

As mentioned above, it is almost impossible to completely prevent cracks in openings in Funkrete walls, but even if cracks occur, if the width does not exceed a certain limit, there will be problems such as water leakage and corrosion of reinforcing bars. It is also true that it will not occur.

The present invention has been made in view of the above-mentioned circumstances, and its purpose is to allow the occurrence of cracks to a certain extent, and to actively distribute and control the cracks to a plurality of trees at predetermined intervals. An inexpensive and easy-to-construct concrete that suppresses the width of cracks within specified limits depending on the purpose and conditions of the building, improves the precision of reinforcement reinforcement, prevents water leakage and reinforcing steel, and increases the durability of buildings. The present invention provides a crack control method and crack control structure in a wall opening.

Embodiments of the present invention will be described below with reference to the drawings.

In FIG. 2, 1 is a concrete wall, 2 is an opening, and an inducing jig 3 for inducing cracks is installed in the concrete wall 1 near the corner 2a of the opening.

As shown in FIG. 3, the triggering jig 3 includes a substrate 3a and two triggering pieces 31) bent at substantially right angles to both ends of the substrate 3a.
It consists of Then, when the back surface of the base plate 3a is arranged along the inner surface of the open corner 2a, and the triggering piece 311 is oriented inward of the concrete wall 1, as shown in FIG. As shown in (A), a crack C is induced from the tip of the inducing piece 3b toward the inside of the concrete wall 1.

A plurality of reinforcing bars 4 are arranged in a direction substantially perpendicular to the crack C, and are integrally assembled by fixing reinforcing bars 4a.

The reinforcing bar 4 is also held in an accurate position by a holding jig 5. As shown in FIG. 4, the holding jig 5 is composed of a substrate 5a, an arm plate 51), and a gripping portion 5c, and the back surface of the substrate 5a is arranged along the inner surface of the opening corner 2a. , the reinforcing bar 4 is fitted into the grip portion 5c.

Since the present embodiment is as described above, for example, if the interval between the induction plates 31 is 50 mm, the amount of shrinkage of the concrete will be 50X 5 .100kg/c…2
Then, the elongation strain of the reinforcing bar 4 is 1,000X], O-6, and the amount of elongation is 50xl, 0(loxl (l bow =
(Since it is 1.05 mm, the width of one crack is 0.
．． 025+0.05=0.075+++m, which prevents water leakage and reinforcing steel. If the purpose is to prevent water leakage, the pitch of the crack-inducing pieces 2+1 and the anchoring reinforcing bars 4a should be doubled, or the stress level of the reinforcing bars 4 should be doubled. Can be doubled.

Next, the construction procedure of the above-mentioned crack control structure will be explained.

First, the formwork for the opening 2 is attached to the outer formwork for the concrete wall 1, and the above-mentioned induction jig 3 is attached to the formwork for the opening.
The substrate 3a of the holding jig 5 is attached to the substrate 5a of the holding jig 5 using nails, screws, adhesive, or the like. Subsequently, the reinforcing bars 4, which are integrally assembled with the fixing reinforcing bars 4a by welding or the like, are fitted into the gripping portions 5c of the holding jig 5, and arranged at accurate positions. Once the reinforcement is completed, the inner formwork is installed and concrete is poured.

Next, FIG. 5 shows another embodiment in which another induction jig 6 is installed in place of the above-mentioned induction jig 3, and reinforcing bars 4 are double reinforced in the thickness direction of the wall 1 and wall 1. As is clear from FIG. 6, the triggering jig 6 is composed of a substrate 6a and a triggering piece 6b.
1] is inclined in one direction with respect to the substrate 6a (in this example, approximately 4
5°).

Moreover, FIG. 7 shows an example of the crack control structure fItJ3, in which ladder reinforcements as reinforcement reinforcements 7 are oriented obliquely to the above-mentioned induction jig 6 so as to be almost orthogonal to the induced cracks C. At the same time, the reinforcing bar 7 is held in a more accurate position by a holding jig 81 as shown in FIG.

Furthermore, FIG. 9 shows a fourth embodiment in which the reinforcing bars 7 are arranged in the thickness direction of the concrete wall 1 and held by a holding jig 9 shown in FIG. 10.

Furthermore, FIG. 11 shows that the reinforcing bar 7 is attached to another holding jig 1.
This shows a fifth embodiment in which the holding jig 10 is held from the same position as the previous one. In this embodiment, cracks are induced from the gripping part 10a of the holding jig 10. Note that the holding jig 1+ii may be replaced with the holding jig 11 shown in FIG. 12.

In FIG. 13, the reinforcing bars 7 mentioned above are double reinforced, and these reinforcing bars 7 are held by the holding 'lf3 tool 1 as shown in FIG. 14.
It is held by 2. In this case, the inner reinforcing bar 7
is held by the first gripping part 12a of the holding jig 12, and the outer reinforcing bar 7 is held by the second gripping part 121)
It is maintained by

In this embodiment as well, cracks are induced from the first gripping portion 12a of the holding jig 12, but a separate induction jig may be provided.

Although the triggering jig of the above embodiment has two triggering pieces arranged at both ends of the board, the present invention is not limited to this, and a plurality of triggering pieces can be arranged side by side at a predetermined interval. It's okay.

Next, the effects of the present invention will be listed.

(1) A plurality of triggering pieces are installed in the concrete wall near the corner of the opening at a predetermined interval and are placed side by side facing the inside of the wall. It is possible to suppress the crack width within a predetermined range and prevent water leakage and reinforcing steel rust from occurring.

(2) The holding jig not only allows the reinforcing bars to be arranged in accurate positions, but also has the effect of simplifying the construction management of the reinforcing bars.

(3) Combination of induction jig, reinforcing bar and holding jig A1'4
Structure (3) The combination structure of the induction jig, reinforcing bars, and holding jig distributes the crack positions and number of cracks almost systematically.
The crack width can be set according to the purpose and conditions of the building.

(4) The crack control structure of the present invention can be applied to areas where shrinkage joints cannot be applied.

[Brief explanation of the drawing]

Figure 1 is a diagram showing the state of cracks at the opening corner of the Funkley-Y wall, Figures 2 (A) and (B) are diagrams showing the first embodiment of the crack control device of the present invention, and Figure 3 is the induced Perspective view of the jig,
Figures 4 (A) and (B) are front and side views of the holding jig;
Figures (A) and (B) are views showing a second embodiment of the crack control device, Figure 6 is a perspective view showing another example of the induction jig, and Figures 7 (A) and (B) are views showing the crack control device. 8(A) and 8(B) are views showing the second embodiment of the holding jig. FIGS. 9(A) and 9(B) are views showing the fourth embodiment of the crack control device.
Figures 10 (A) and (B) are diagrams showing a third embodiment of the holding jig, and Figures 11 (A) and (B) are diagrams showing a fifth embodiment of the crack control device. Show M, Chiku12tlili
l is a diagram showing a modified example of the holding jig shown in Fig. 11;
The figures show the sixth embodiment of the crack control device and the fourteenth embodiment.
Figures (A) and (B) are diagrams showing still another embodiment of the holding jig. ' 1... Concrete wall, 2... Opening, 2a.
... Corner, 3... Induction jig, 3a... Board, 3b.
... triggering piece, 4... reinforcing muscle, 4a... anchoring reinforcement muscle,
5... Holding jig, 5a... Board, 51)... Arm plate,
5C... Gripping part, 6... Induction jig, 6a... Substrate, 6b... Induction piece, ? ...Reinforcement bar, 8,9.10・
...Holding jig, 10a...Gripping part, 11.12...
Holding jig, 12a...first gripping part, 121)...second
Grip part, C...Crack. Patent applicant: Tokyu Construction Co., Ltd. Figure 5 (A) (B) Figure 16 Figure 7 (8) □ (A) (B) Figure 9 CB) Figure 10 (A) (B) Figure 12 Figure 13 Figure 14 (A) (B)

Claims (1)

[Claims] (1) The cracks in the 1'' portion between the concrete walls are actively induced to disperse using an inducing jig, so that the width of each crack is suppressed within a predetermined limit. A crack control method in concrete wall openings characterized by: (2) Cracks in a patent opening characterized in that the above-mentioned inducing jig consists of a plurality of inducing pieces arranged in parallel inward of the wall at predetermined intervals in the concrete wall near the corner of the opening. Control method. <3) A plurality of triggering pieces are oriented inward at predetermined intervals in parallel to each other, reinforcing bars are arranged almost orthogonally to the cracks induced by the triggering pieces, and the reinforcing bars are held and cured. A structure for controlling cracks in an opening in a concrete wall, characterized by being held in place by a tool. (4) The structure for controlling cracks in an opening in a concrete wall according to claim 3, wherein the holding jig is composed of a base plate, an arm plate, and a gripping part.