JP2546086B2 - Manufacturing method of precast concrete members - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a precast concrete member having a hollow section having a rectangular cross section or a U-shaped groove section which also serves as a mold.

[0002]

2. Description of the Related Art As a method for manufacturing a column precast member having a thin hollow portion having a rectangular cross section or a beam precast member having a thin groove portion having a U-shaped cross section, an inner mold having irregularities is used. Buried using a metal lath.
Centrifuge molding. There have been means such as using an elastic body form such as a rubber tube.

However, the above conventional method has the following problems. When an inner mold is used, it becomes difficult to remove the mold. In particular, if the inner mold has irregularities, it becomes very difficult. If metal lath is used, slag leaks during manufacturing, which is a problem in ensuring quality. In addition, the cost is high because it is buried.
Centrifugal molding requires large-scale equipment and cannot be easily manufactured. In the case of using an elastic body form, the cross section becomes round in order to inflate gas and inflate, and even if restrained by a hoop muscle or the like, the roundness remains and the wall thickness is not uniform. If the wall thickness is not uniform, the work of arranging can not be performed accurately, and the condition is not good.

The present invention has been made in view of the above problems. It is an object of the present invention to propose a method for manufacturing a precast concrete member having a hollow portion or a groove portion which also serves as a formwork, with a uniform thickness and a high productivity.

[0005]

This method for producing a precast concrete member is a method for producing a precast concrete member that also serves as a mold having a hollow portion having a square cross section or a groove portion having a U-shaped cross section. Each side is a rigid flat plate that covers the entire surface of each side, and the corners of the four sides are sealed inner molds made of flexible materials. After pressurizing and pressurizing gas into a predetermined cross-sectional size, after placing concrete between the inner and outer molds, exhausting the gas in the inner mold to reduce the pressure, the corners are contracted and the four sides It is characterized in that it is located on the inner side of the side, and the inner formwork dimension is small to remove the mold.

[0006]

[Function] When gas is pressed into the inner mold to pressurize it, the four sides are not round because the entire surface is a rigid flat plate, and the cross section is almost square. The hoop muscles around the outer mold are arranged. Alternatively, since it is constrained by stirrup streaks, a rectangular cross section with a predetermined size can be obtained. Therefore, it is possible to manufacture a member having a uniform thickness and an uneven inner surface with high accuracy, and it is possible to make the member thin. By exhausting the gas in the inner formwork to reduce the pressure, the flexible material at the corners of the four sides is contracted, the cross-sectional dimensions are made small, and the concrete surface and the inner formwork are peeled off and easily removed. Since it can be molded, productivity can be increased.

[0007]

1 and 2 show an inner formwork 1 used in the embodiment.
It has a rectangular cross section and is hermetically sealed, and has an inlet / outlet port 2 for injecting and exhausting gas at one end. Inner formwork 1
The four sides of each are composed of rigid plates 3 extending over the entire side,
On its surface, there are many projections 4 in the shape of a rectangular parallelepiped. Protrusion 4
Is for ensuring the integrity with the post-cast concrete, but may be omitted if it is not necessary in design. The corners of the four sides are composed of a rubber elastic film body 5 which is a flexible material. The elastic film body 5 is adhesively laminated with the lower surfaces of the rigid flat plates 3 on the four sides to be continuous, and forms the inner surfaces of the four sides of the inner mold 1.

In this inner mold 1, when the gas is injected from the injection / exhaust port 2 and pressurized, the elastic film body 5 at the corner portion expands,
A rectangular cross section having a predetermined size is formed. When the gas in the inner mold 1 is exhausted and decompressed, the elastic film body 5 at the corner portion contracts or bends to shrink the corner portion, and the cross-sectional dimension becomes small, as shown in FIG.

In order to manufacture a precast concrete member for a column that also serves as a formwork having a hollow section with a rectangular cross section by this manufacturing method, as shown in FIG. The muscle 8 is arranged, and the inner formwork 1 is inserted inside the muscle 8 in a contracted state. When gas is pressed into the inner mold 1 after insertion, the rigid flat plates 3 on the four sides of the inner mold are constrained by the hoop muscles 8 to form a rectangular cross section with a predetermined size. In this state, concrete 9 is placed between the inner and outer molds 1 and 6, and the concrete 9
After curing, the inner formwork 1 is contracted and released from the mold as shown in FIG. Although FIG. 4 shows a manufacturing example in which concrete is poured in the axial direction, as shown in FIG. 5, it is possible to open one of the outer molds and pour concrete from the open surface. FIG. 6 shows a precast concrete member for a column having the obtained hollow section 10 having a rectangular cross section and having unevenness 11 on the inner surface.

Similarly, an outer mold 6 having a U-shaped cross section shown in FIG.
After Haisuji the main reinforcement 7 and the stirrup muscle 12 in ^', the inner mold 1 is inserted into the inside, concrete 9 between the inner and outer mold 1,6 Da設, and demolding 8 It is possible to make a precast concrete member for a beam that has a grooved portion 13 having a U-shaped cross section as shown and has unevenness 11 on the inner surface. Further, as shown in FIG. 9, it is also possible to invert the precast member and cast concrete.

In the above-mentioned embodiment, the inner main frame outer peripheral main bar and the hoop or stirrup bar are arranged.
There may be no main muscle and only the hoop muscle or stirrup muscle may be arranged.

[0012]

The present invention is as described above, and according to this manufacturing method, it is possible to manufacture a precast concrete member having a hollow portion or a groove portion, which also serves as a formwork, with high accuracy and high productivity. You can

[Brief description of drawings]

FIG. 1 is a perspective view of an inner mold.

FIG. 2 is a cross-sectional view of a state in which gas is pressed into the inner mold to inflate it.

FIG. 3 is a cross-sectional view showing a state in which the gas in the inner mold is exhausted and contracted.

FIG. 4 is a cross-sectional view showing a state in which concrete is cast in an inner mold to produce a precast concrete member for a pillar.

FIG. 5 is a cross-sectional view showing another embodiment example of manufacturing a precast concrete member for a pillar.

FIG. 6 is a perspective view of a manufactured precast concrete member for a pillar.

FIG. 7 is a perspective view of an outer formwork for manufacturing a precast concrete member for a pillar.

FIG. 8 is a perspective view of the manufactured precast concrete member for a beam.

FIG. 9 is a cross-sectional view showing another example of a method for manufacturing a precast concrete member for a beam.

[Explanation of symbols]

1 ... inner form, 2 ... injection / exhaust port, 3 ... rigid plate, 4 ... projection,
5 ... Elastic film body, 6 ... Outer form, 7 ... Main bar, 8 ... Hoop bar,
9 ... concrete, 10 ... hollow part, 11 ... unevenness, 12 ... stirrup streak, 13 ... groove part.

Claims (1)

(57) [Claims] 1. A method of manufacturing a precast concrete member which also has a hollow section having a square cross section or a groove section having a U section, and which is a rigid flat plate having a square section and four sides extending over the entire surface of each side. , The corners of the four sides are inserted into the inner mold of the closed mold made of each flexible material inside the outer mold, and gas is pressed into the inner mold to pressurize and the prescribed cross-section is not obtained. After placing concrete between the inner and outer molds, the gas in the inner mold is exhausted and decompressed to shrink the corners to the inner side of the four sides and reduce the inner mold dimensions. A method for manufacturing a precast concrete member, which comprises demolding as a mold.