JPH0872048A - Device and method for casting u-type precast concrete beam - Google Patents

Abstract

PURPOSE: To contrive to improve the efficiency of the mounting work of inner forms and to facilitate or the like the handling during transportation, storage and at molding in the device and method for casting a U-type precast concrete beam. CONSTITUTION: A reinforcing bar assembly consists of a plurality of beam longitudinal bars 2, hoops 3 and inner lattice bars 5. A casting device consists of a U-shape peripheral form 12, a plurality of plate-like inner forms 21 for blocking between the beam longitudinal bars and bag-like bodies 22 for internal pressure inserted in respective spaces partitioned by the inner lattice bars 5. At the bottom surface of the peripheral form 12, a recessed part 16, in which the lower end part of the reinforcing bar assembly 1 is housed. After the reinforcing bar assembly 1 is housed in the peripheral form 12 under the condition that the respective bag-like bodies 22 and inflated so as to fix the respective inner forms 21, concrete is placed in the peripheral form 12 so as to cast an inverted U-shape concrete wall.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a U-shaped precast concrete beam forming apparatus and a method for forming a U-shaped precast concrete beam having a reinforcing bar assembly having a medium lattice reinforcement.

[0002]

2. Description of the Related Art Conventionally, as a molding apparatus of this kind, as a means for arranging an inner mold such as a plate material in a rectangular cross section in a peripheral mold having a U-shaped cross section, and fixing the plate material. It uses various pipes and bolts and is fixed to the surrounding formwork.

However, when molding a U-shaped precast concrete beam containing a reinforcing bar assembly, a clamp member or the like is passed between cage-shaped reinforcing bar assemblies in order to fix the inner mold to the peripheral mold. In addition, an inner formwork fixture such as a pipe has to be attached to the space inside the rebar assembly, which requires a lot of work.

In particular, in a rebar assembly having a rebar assembly that crosses the inner space, the inner space is divided into a plurality of spaces by the middle rebar, and each space is very narrow. , It becomes more difficult to mount and fix the inner formwork, and the work efficiency decreases.

The applicant of the present application has proposed a method for forming a U-shaped precast concrete beam in Japanese Patent Application No. 1-164844, in which a rubber air mat is directly used as an inner mold, whereby a mold device is formed. It is intended to facilitate the assembly of and improve work efficiency.

[0006]

However, Japanese Patent Application No. 1-16
The structure or method of No. 4844 has the following problems. (1) When concrete is molded, it is molded in the same U-shape as when it is in use. Therefore, when pouring concrete, it must be poured into the form from a narrow space on both sides of the rebar assembly. , Work efficiency is not good. It also takes time to pour it evenly into the bottom of the U-shape.

(2) A rubber air mat is directly used as an inner frame, and the surface of the bag-like body is used as a concrete forming surface. However, the elastic bag-like body itself expands so as to approach a round shape. As a result, the concrete forming surface becomes round and it is impossible to set it in a predetermined prismatic shape. Specifically, when the bag-shaped body is inflated, the bag-shaped body protrudes outward from between the beam main bars and cannot be set in a predetermined prismatic shape.

(3) When the bag-shaped body expands so as to protrude from the space between the beam main bars, a local stress is applied to the beam column main bar from the bag-shaped body, and the beam main bar is bent. When the concrete is solidified with the beam main bar bent in this way, the U-shaped precast concrete beam as a product
It will not be possible to maintain sufficient strength at the beginning of design.

(4) In a structure in which the elastic bag-shaped body is inflated and its surface is directly used as a concrete forming surface and brought into contact with concrete, the bag-shaped body is quickly damaged and can be used repeatedly. It is uneconomical.

(5) U-shaped precast concrete beams are poured into the hollow part of a building site at the site where concrete is poured into them to form a solid concrete beam. The inner surface of the U-shaped concrete beam is formed in a concave-convex shape in order to strengthen the connection with the concrete poured in. In order to form the unevenness, in the above-described conventional elastic bag-shaped body, a large number of projections are formed on the surface itself of the elastic bag-shaped body. However, it is technically very difficult to form unevenness on the surface of the expandable elastic bag. For example, when a large number of protrusion members are attached, they are easily peeled off during expansion and also cause deformation during expansion.

[0011]

It is an object of the present invention to simplify the structure for mounting and fixing the inner formwork, improve the work efficiency thereof, and maintain the quality of the concrete beam.

[0012]

According to the first aspect of the present invention,
A plurality of beam main bars arranged parallel to each other and having a rectangular cross section,
For forming a concrete wall in a U-shaped cross-section around a reinforcing bar assembly composed of a plurality of hoop reinforcements that bind the beam main reinforcements from the outer peripheral side and a middle lattice reinforcement that crosses the internal space formed by the beam main reinforcements In a U-shaped precast concrete beam forming device, a U-shaped peripheral formwork having a cross-sectional shape,
It can be inserted into each space defined by a plurality of plate-shaped inner molds and intermediate lattice reinforcements that are arranged so as to close each space between adjacent beam main reinforcements, and it can be expanded by injecting fluid It is equipped with a plurality of bag-shaped bodies that apply internal pressure to the formwork, and the bottom of the peripheral formwork is formed with a recess for accommodating the lower end of the rebar assembly at a position lower than the lower molding surface, thereby increasing the height of the peripheral formwork. The U-shaped precast concrete beam forming apparatus is characterized in that the height is set to have a space for forming a concrete wall above the reinforcing bar assembly when the reinforcing bar assembly is stored.

According to a second aspect of the present invention, a plurality of beam main reinforcements parallel to each other, a plurality of hoop reinforcements for binding the beam main reinforcements from the outer peripheral side, and an inner space formed by the beam main reinforcements are provided. In the method of forming a U-shaped precast concrete beam that forms a concrete wall with a U-shaped cross-section around a rebar assembly consisting of a middle lattice bar, a plate-shaped inner mold that closes the space between adjacent beam main bars While arranging the frame, insert an inflatable bag-shaped body into each space partitioned by the grid lattice, and inflate the bag-shaped body to press and fix each inner formwork to the outside. The cross-sectional shape of the U-shaped peripheral formwork is such that the upper end of the rebar assembly is lower than the upper end of the peripheral formwork, and the lower end of the rebar assembly is the lower molding surface of the peripheral formwork. So that it projects more downward than
A method for forming a U-shaped precast concrete beam, characterized in that the reinforcing bar assembly is stored and supported, concrete is poured from above the peripheral formwork, and the U-shaped pre-cast concrete beam is formed in the state opposite to the state in use. .

[0014]

[Embodiment of Forming Apparatus] FIGS. 1 and 2 show a reinforcing bar assembly 1 incorporated in a U-shaped precast concrete beam according to the present invention. In FIG. 2 showing a sectional view, the reinforcing bar assembly 1 is A plurality of beam main reinforcements 2 arranged in parallel with each other in a rectangular cross section, a plurality of rectangular hoop reinforcements 3 for binding the beam main reinforcements 2 from the outer peripheral side, and an internal space having a rectangular cross section formed by the beam main reinforcements 2 It is composed of the middle lattice streaks 5 and 6 provided. The beam main reinforcements 2 are provided on the upper side and four on the lower side. As the intermediate lattice reinforcements 5 and 6, elongated rectangular rectangular rebar members 5 and lateral rebar members 6 are provided. These middle lattice bars 5 and 6 divide the cross section of the rebar assembly 1 into six upper and lower two spaces S1 ... S6.

In FIG. 1 showing an overall side view, the main beam 2
A fore edge mold frame end plate 15 forming a part of the peripheral mold is detachably attached to each of both ends.

FIG. 6 is a sectional view of the peripheral formwork 12 of the molding apparatus to which the invention according to claim 1 of the present application is applied.
Reference numeral 2 denotes a horizontal base board 13 which is long in the front-rear direction, and a pair of left and right side plates 14 which are vertically provided on the base board 13, and is formed in an upward U-shape. The mold end plate 15 is provided.

A pair of left and right spacers 17 having a constant thickness are fixed on the upper surface of the base board 13, and the spacers 1
The upper surface of 7 is used as the lower forming surface. Spacer 17
The recessed portion 16 formed between them corresponds approximately to the width of the reinforcing bar assembly 1, and the lower end portion of the reinforcing bar assembly fits into the recessed portion 16 when the reinforcing bar assembly is inserted.

FIG. 3 is a perspective view of the inner frame 21 and the elastic bag 22 for applying internal pressure. The inner formwork 21 is divided into strip plate shapes corresponding to the spaces as shown in FIG. 3 so as to close the spaces between the main reinforcements of the beams of the reinforcing bar assembly 1 of FIG. 2, and is made of a hard resin. However, since it is not necessary to form a concrete wall on one side of the cross section, the strip-shaped inner formwork 2
A total of 7 sheets of 1 are prepared.

The elastic bag-like body 22 of FIG. 3 is provided with one having an expanded cross-section of a size that can sufficiently correspond to the cross-sectional shape of each of the spaces S1 to S6 partitioned by the intermediate lattice lines 5 and 6 of FIG. ing. Each elastic bag 22 is formed of rubber or the like in an elongated shape, one end is sealed, and the other end is filled with an air injection part 25.
have. In this embodiment, the partitioned spaces S1 ... S of FIG.
Corresponding to No. 6, a total of six elastic bag-shaped members 22 shown in FIG. 3 are provided, and their bulging shape is formed to have a rectangular cross-section as much as possible.

FIG. 8 shows a cross-sectional shape of the strip-shaped inner mold 21. Both end portions in the width direction of the inner mold 21 are inclined surfaces 21a so that the outer side becomes narrower, A large number of protrusions 24 are integrally formed on the outer surface.

FIG. 9 shows an air supply mechanism for injecting air into the bag-like body 22, which comprises an air pipe 31 connected to the air compressor 30 and two branch pipes 32 branched from the air pipe 31. Each branch pipe 32 has an opening / closing valve 33 and a pressure gauge 34.
And three compressed air outlets 35 each are provided.
Is provided. The air injecting portion 25 of the bag-shaped body 22 is connected to each of the air outlets 35 via an air hose 37.

As a connection method, for example, three bag-like bodies 22 inserted into the lower spaces S4 to S6 and three bag-like bodies 22 inserted into the upper spaces S1 to S3 are used.
The two branch pipes 32 of FIG. 9 are separately connected. That is, by operating one on-off valve 33, it is possible to simultaneously inject air into the three bag-shaped bodies 22 in any upper or lower stage.

[0023]

[Example of forming method] An example of a forming method of a U-shaped precast concrete beam using the forming apparatus will be described.
First, as in the following steps (1) to (6), the strip-shaped inner mold 21 and the bag-shaped body 22 are attached to the rebar assembly 1 assembled in advance.

(1) In FIG. 4, elastic bag-like bodies 22 corresponding to their cross-sectional shapes are inserted into the lower spaces S4 to S6 of the reinforcing bar assembly 1 in a deflated state.

(2) 3 inserted in the spaces S4, S5, S6
About one-third of the air is put into one bag-shaped body 22, and the four corners of each bag-shaped body 22 are aligned with the four corners of the spaces S4, S5, S6.

(3) An inner mold 21 is inserted between the beam main bars 2 corresponding to the side surfaces of the spaces S4, S6.

(4) Upper spaces S1, S2, as shown in FIG.
The bag-shaped body 22 is inserted into S3, and while the bag-shaped body 22 is filled with air by about 2/3, the four corners of each bag-shaped body 22 are separated into spaces S1, S.
Prepare according to the four corners of S2 and S3.

(5) A corresponding inner formwork 21 is provided between the beam main bars on the upper surfaces of the spaces S1, S2, S3 and the side surfaces of the spaces S1, S3.
Plug in.

(6) When all the bag-shaped bodies 22 are inserted into the corresponding spaces and all the plate-shaped inner molds 21 are inserted between the corresponding column main bars, the bag-shaped bodies 22 are filled with 0. Inject air up to 9 kgf / cm ² .

(7) All inner molds 21 and bags 22
Reinforcing bar assembly 1 incorporating
2 and suspend the lower end of the rebar assembly 1 from the peripheral formwork 12
Fits in the recess 16 at the bottom of the front and rear edge frame end plates 15
Are fixed to the front and rear ends of the base plate 13 and the side plate 14. In this case, since the front plate 15 is already fixed to the end of the reinforcing bar assembly 1, the rear end plate 15 is inserted into the rear part of the beam main bar 2 and fixed to the rear surface of the base board 13 or the like.

(8) Six bag-shaped bodies 22 each having 1.2 kgf / cm
Air is injected up to ² at the same time, and each inner mold 21 is pressed from the inside and pressed against the hoop muscle 3 to be fixed. Further, in this case, since both ends in the width direction of the inner formwork 21 are the inclined surfaces 21a, the inclined surfaces 21a hit the beam main bars 2 and the beam main bars can be tightly closed.

(9) In FIG. 6, first, concrete is poured (poured) on both left and right sides like P1, and then P
Place it in the upper part as shown in 2.

(10) Within 2.5 hours to 3.0 hours after casting, the inner mold 21 and the bag-like body 2 should be protected from impact.
Remove 2.

(11) After the casting, 6.0 hours or more, a sheet or the like is put on and steam curing is performed.

(12) Finally, a U-shaped precast concrete beam as shown in FIG. 7 is completed. It should be noted that FIG. 6 is formed in an inverted state so that the bottom wall portion is on the upper side, and in FIG. 7, it is shown returned to the normal use state.

[0036]

According to the inventions described in claims 1 and 2, the following effects can be obtained. (1) Bag-shaped body 22 in which the inner mold 21 is inserted into the inner mold
Since it is fixed to the rebar assembly 1 by expanding,
Compared to the conventional structure in which the inner formwork is fixed to the peripheral formwork with pipes, clamps, bolts, etc., the work of attaching and fixing the inner formwork is simple, and the transport and storage are also easy.

Particularly, when the rebar assembly 1 is provided with the intermediate lattice bars 5 and 6, in the conventional inner frame fixing structure using a pipe or the like, bolt fastening work or the like must be performed in a very narrow space. However, the mounting and fixing work becomes very difficult. However, as in the present invention, the plate-shaped inner formwork 21 is divided so as to correspond to the space between the beam main bars, and the middle lattice bars 5, Bag-shaped body 2 for each of spaces S1 to S6 partitioned by 6
If 2 is inserted and the inner formwork 21 is pressed and fixed by the expansion of the bag-shaped body 22, the improvement of the mounting work efficiency becomes more remarkable.

(2) Since the inner mold 21 is pressed and fixed by inflating the bag-like body 22, the pressing force is evenly applied to the entire inner mold 21 and each inner mold 21 is stabilized. It can be pressed in the state and the quality is improved.

(3) Since the shape of the inner mold 21 is divided into a shape corresponding to the space between the beam main bars and is inserted between the pillar main bars, it is easy to mount and position the inner mold 21.
There is no fear of slipping during the placement work.

(4) When the concrete is solidified while the reinforcing bars are locally stressed, the reinforcing bars themselves are fixed in a bent state, and the strength at the initial design cannot be obtained. Then, since the inner mold 21 of the plate material is interposed between the beam main bars, the bag itself does not have a space between the beam main bars as in the case where the bag-shaped body is directly used as an inner mold. It will not stick out from the bar and local stress will not be applied to the reinforcing bar, and the strength at the beginning of the design can be maintained,
Quality can be maintained. Of course, the inner peripheral surface of the concrete is also formed into a prismatic shape without rounding, and the thickness of the concrete peripheral wall can be formed uniformly, and the quality can be maintained in this respect as well.

(5) Compared with the conventional structure in which the elastic bag-shaped body is directly used as the inner formwork, the bag-shaped body 22 is not directly used as the concrete forming surface in the present invention, so that the bag-shaped body 22 is directly used. It does not come into contact with concrete, the bag-like body 22 is less damaged, and can be used repeatedly.
It is economical.

(6) The U-shaped precast concrete beam is a solid concrete beam, in which concrete is injected into the hollow portion of the U-shaped precast concrete beam and the surrounding wall is formed integrally with the hollow portion. The unevenness for strengthening the connection between the already molded peripheral wall and the concrete that will be molded on-site later can be formed on the plate-shaped inner formwork, and the unevenness is directly formed on the bag-shaped body as in the past. The unevenness can be formed more easily than the case.

(7) Since it is formed in a U-shape that opens downward, which is the opposite of the one used, concrete can be poured easily from above, and the manufacturing work efficiency is improved.

(8) Bottom wall portion 1 of U-shaped concrete member
Since b is formed on the upper side at the time of molding, it is possible to fill the bottom portion uniformly and quickly.

[0045]

[Other Examples]

(1) The present invention is not limited to the rebar assembly having the cross-shaped one as shown in FIG. 2 as the center lattice, but can be applied to the one having one of the vertical orientation and the horizontal orientation. In that case, the number of bag-shaped bodies is changed according to the partitioned space.

[Brief description of drawings]

FIG. 1 is a side view of a reinforcing bar assembly according to the present invention.

2 is an enlarged cross-sectional view taken along the line II-II of FIG.

FIG. 3 is a perspective view of an inner formwork and a bag-shaped body according to the present invention.

FIG. 4 is a cross-sectional view of a reinforcing bar assembly showing an inner form fitting step.

FIG. 5 is a cross-sectional view of a reinforcing bar assembly showing a state in which an inner formwork and a bag-shaped body are attached.

FIG. 6 is a vertical cross-sectional view of a molding apparatus showing a concrete placing step.

FIG. 7 is a vertical cross-sectional view of a U-shaped precast concrete beam showing a state at the time of completion.

FIG. 8 is a sectional view of an inner mold.

FIG. 9 is a piping diagram of the air supply device.

[Explanation of symbols]

 1 Reinforcing Bar Assembly 2 Beam Main Bar 3 Hoop Bar 5 Middle Lattice Bar 12 Peripheral Form 16 Recess 21 Inner Form 22 Bag-shaped Body

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tadamitsu Saimoto 1-22-20 Shimanouchi, Chuo-ku, Osaka City, Osaka Prefecture Daisue Prefab Co., Ltd.

Claims (2)

[Claims] 1. A plurality of beam main bars arranged in parallel with each other and having a rectangular cross section, a plurality of hoop bars for binding the beam main bars from the outer peripheral side, and a middle lattice bar crossing an internal space formed by the beam main bars. In a forming device of a U-shaped precast concrete beam for forming a concrete wall with a U-shaped cross section around a rebar assembly consisting of, a peripheral formwork having a U-shaped cross-section and an adjacent beam main bar It can be inserted into each of the multiple plate-shaped inner molds that are placed so as to close each space and each space that is partitioned by the medium lattice muscles, and it is expanded by the injection of fluid and internal pressure is applied to each inner mold. The bottom of the peripheral formwork is provided with a recess for accommodating the lower end of the rebar assembly at a position lower than the lower molding surface. For concrete wall molding on the upper side of the rebar assembly when stored An apparatus for forming a U-shaped precast concrete beam, characterized in that it has a height having a space portion. 2. A plurality of beam main bars that are parallel to each other, a plurality of hoop bars that bind the beam main bars from the outer peripheral side, and a middle lattice bar that is provided so as to cross the internal space formed by the beam main bars. In a method of forming a U-shaped precast concrete beam around a reinforcing bar assembly, which has a U-shaped cross section, a plate-shaped inner formwork is arranged in a space between adjacent beam main bars, Insert an inflatable bag-like body into each space partitioned by the lattice lattice, and inflate the bag-like body to press and fix each inner formwork outward, opening in cross-sectional shape. Inside the U-shaped peripheral formwork, the upper end of the reinforcing bar assembly is lower than the upper end of the peripheral formwork, and the lower end of the reinforcing bar assembly projects below the lower forming surface of the peripheral formwork. So that the rebar assembly can be stored and supported, and above the peripheral formwork. A method of forming a U-shaped precast concrete beam, which comprises injecting concrete from the mold and molding it into a U-shape with a downward opening that is the reverse of the state when used.