JPH0443585Y2 - - Google Patents

Description

[Detailed Description of the Invention] "Industrial Application Field" The present invention relates to a prevention plate for preventing cracks from occurring in a concrete wall around the corner of a front sash.

``Prior art'' Prior to pouring concrete to form a concrete wall, a sash (joint frame) is assembled into the formwork, and then concrete is poured to form a concrete wall. A pre-installation method that also completes the installation of the sash is generally known.

``The problem that the idea is trying to solve'' However, in general, in reinforced concrete buildings,
After concrete is placed, heat of hydration is generated, hardens, and then dries. For this reason, walls with a large specific surface shrink more than columns or beams with a small specific surface, and this difference in the amount of strain can cause cracks, but especially when there is an opening, cracks occur at the corner of the opening. I have an easy problem to solve.

Conventionally, as structures for preventing this type of cracking, concrete walls with stress-relaxing induction joints formed on the surface, or concrete walls with internal reinforcing bars or meshes, etc., have been known. As a means to prevent this, methods such as curing the surface of the concrete wall around the pre-attached sash by covering it with a wooden mold are known, but there is currently a desire for a more efficient structure or means to prevent cracking. It's a situation.

"Purpose of the invention" The present invention was made in view of the above-mentioned circumstances, and is capable of preventing cracks in the concrete wall surrounding the leading sash, as well as preventing distortion of the leading sash, and preventing the corners of the leading sash from being cracked. The purpose of this invention is to provide a crack prevention board that can provide protection.

"Means for solving the problem" The present invention has a plate shape with a corner part that spans and matches the outer edge of the corner part of the front sash,
It is made by forming through holes at required positions.

``Function'' The prevention plate, which is fixed on the outside of the corner with its corner part aligned with the corner of the tip-attached sash, prevents distortion of the sash and protects the corner, and also protects the corner of the tip-attached sash. It is buried inside the concrete to prevent cracking.

``Example'' Figures 1 and 2 show a prevention plate 1 according to an embodiment of the present invention being attached to four corners 2 of a sash (joint frame) 2.
This shows the state in which each of a is fixed. The pre-attached sash 2 is constructed by assembling a vertical frame and a horizontal frame into a rectangular shape, and attaching corner reinforcing materials 2b to each corner 2a, and is a mold that is assembled to form a concrete wall at a construction site. When a concrete wall is built by being attached to a predetermined position on the frame and pouring concrete around it after installation, it is used to complete the installation of the first sash 2 at the same time as the concrete pouring. It is something that The above-mentioned prevention plate 1 is
It consists of a rectangular iron plate 1A, and one corner of the plate 1A has a corner 2 of the tip-attached sash 2.
A notch-shaped corner portion 1a is formed that spans and matches the outer edge of the plate 1A, and the plate 1A has a diameter that is approximately a fraction of the length of one side of the plate 1a. Several circular through holes 1b are formed, and the outer edge of the plate 1A on the side facing the corner 1a is bent by folding the outer edge of the plate 1A perpendicularly to the plate 1A. Portions 1c, 1c are formed, and portions of the bent portions 1c, 1c that contact each other are welded. As shown in FIG. 2, the prevention plate 1 has the corner portion 1a in close contact with the widthwise center portion of the outer surface of the corner reinforcing material 2b provided at each corner portion 2a of the tip-attached sash 2. The corner portion 1a is welded and fixed to the corner reinforcing member 2b.

The pre-attached sash 2 with the prevention plates 1 attached to the four corners as described above is provided at a predetermined position within a formwork for forming a concrete wall at a construction site.
After that, concrete is poured into the formwork, the concrete is hardened, and a concrete wall is formed to be fixed to the concrete wall. Here, since the corner portion 2a of the tip-attached sash 2 is protected by the prevention plate 1, even if force or impact is carelessly applied to the tip-attached sash 2 during the above-mentioned work, the tip-attached sash 2 will not be distorted. There are almost no For this reason, compared to the conventional method where it was necessary to attach wooden molds to the corners of the first sash for temporary curing, when the prevention plate 1 of the present invention is used, the use of wooden molds can be minimized. Temporary curing costs can be reduced. Also,
When the concrete is poured, the prevention plate 1 will be embedded in the concrete wall, but the prevention plate 1 will bear the tensile stress generated at the corner of the concrete wall opening due to drying shrinkage of the concrete, resulting in many small cracks. This effectively reduces visible cracks around the corner portion 2a of the first sash 2, thereby preventing cracks. Furthermore, cracks that occur in concrete walls are further reduced with the aid of reinforcing bars and steel mesh embedded within the concrete walls than with conventional methods.

In addition, when concrete is poured around the prevention plate 1, the concrete on the front side and the back side of the prevention plate 1 are dried while being in contact with each other through the through holes 1b, so that the placed concrete and the prevention plate are It joins well with 1.

By the way, the shape of the prevention plate 1 is not limited to the shape shown in FIGS. 1 and 2, but may be polygonal as shown in FIGS. 3 and 4, or as shown in FIGS. 5 to 7. It may be approximately L-shaped. The width and size of the prevention plate 1 are set to such a value that it does not interfere with the side walls and small walls provided around the front sash 2.

Furthermore, the prevention plate 1 of the present invention can be freely used in conjunction with conventional crack prevention structures and prevention means. Therefore, it is also possible to bury reinforcing reinforcing bars, mesh, etc. in the concrete wall around the pre-attached sash 2, or to form induced joints.

"Effects of the invention" As explained above, the prevention plate of the invention has a plate shape with a corner part that straddles and matches the outer edge of the corner part of the tip-attached sash, and has through holes formed at predetermined positions. Therefore, by aligning the corner portion with the corner portion of the tip-attached sash and fixing it to the corner portion, it is possible to prevent the occurrence of distortion of the tip-attached sash and protect the corner portion. In addition, when concrete is poured around the pre-attached sash to form a concrete frame, the prevention plate is buried in the concrete frame outside the corner, preventing cracks in the concrete wall around the prevention plate. can. Furthermore, the holes formed in the prevention plate allow the concrete on both the front and back sides of the prevention plate to be continuous through the hole.
The poured concrete blends well with the prevention plate.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of the present invention. Figure 1 is a front view of a front sash with prevention plates attached to the four corners, and Figure 2 shows how the prevention plate is attached to the front sash. A perspective view, FIG. 3 is a front view showing a second example of a prevention plate, FIG. 4 is a front view showing a third example of a prevention plate, and FIG. 5 is a front view showing a fourth example of a prevention plate. , FIG. 6 is a front view showing a fifth example of the prevention plate, and FIG. 7 is a front view showing a sixth example of the prevention plate. 1...Preventing plate, 1a...corner part, 1b...through hole, 2...pre-attached sash (joint frame), 2a...corner part.

Claims (1)

[Scope of utility model registration request] It has a plate shape with a corner part that straddles and matches the outer edge of the corner of the first sash, and the corner part is brought into contact with the corner of the first sash before concrete is poured. This is a prevention plate fixed to the outside and has through holes formed at required positions to prevent concrete from cracking around the pre-attached sash.