JPH06238630A - Manufacture of half-precast beam - Google Patents

Abstract

PURPOSE:To manufacture a half-precast beam of high strength by eliminating the troublesome compaction work using super-high strength concrete of low consistency at the time of placing and carrying out accurate placing. CONSTITUTION:Reinforcing bars 20 are inserted and disposed respectively into a plurality of gutter-shaped molds 10, and a plurality of gutter-shaped molds 10 are disposed radially around a rotating axial center O with their respective openings 11c disposed on the inner diameter side and bound thereon, and concrete C is filled in respective gutter-shaped molds 10 and rotated as the rotating axial center as its rotating center O to place the concrete.

Description

Detailed Description of the Invention

[0001]

The present invention relates to reinforced concrete (R
The present invention relates to a method of manufacturing a half precast beam made of concrete having extremely high strength, which is used for a rigid frame structure in a construction.

[0002]

2. Description of the Related Art Half-precast beams are reinforced concrete products that have been produced in advance in concrete factories and are used for frame frames in reinforced concrete construction. Further, the design often requires high strength of the concrete. Conventionally, in the production of such a half-precast beam, in a horizontally placed gutter-shaped formwork, first rebar the required reinforcing bars consisting of the bottom main rebar and ribs, and then fill with concrete, By vibrating and consolidating this concrete with a vibrator, precise placement is performed and the strength is improved. In addition, since the strength of concrete generally increases as the ratio of water to cement decreases, the concrete used for placing half-precast beams can be made extremely solid by kneading with a small amount of water. There is.

[0003]

However, according to the above-mentioned conventional manufacturing method, in order to densely cast concrete and obtain a half precast beam having extremely high strength, a large number of concrete is filled in the formwork. It is necessary to insert a vibrator at a location to perform compaction by vibration, and it is often difficult to insert the vibrator depending on the shape of the reinforcing bar. In addition, since the concrete used for placing half-precast beams has a small amount of water for the purpose of obtaining extremely high strength, the workability, that is, the softness (flowability) at the time of placing is low, and the formwork It is difficult for the material to easily spread throughout the interior. Therefore, it takes a lot of time to perform precise placement using the vibrator, and the compaction work is complicated.

The present invention has been made under the circumstances as described above, and its technical problem is to easily obtain a half precast beam that is densely cast and has extremely high strength. An object of the present invention is to provide a possible manufacturing method.

[0005]

The above-mentioned technical problems are as follows.
The present invention can effectively solve the problem. That is, the method for manufacturing a half-precast beam according to the present invention, the reinforcing bars are respectively arranged in the plurality of gutter-shaped molds to arrange the reinforcing bars, and the openings of the plurality of gutter-shaped molds are located on the inner diameter side. The concrete placement is performed by radially arranging and binding around the rotation axis, filling the plurality of gutter-shaped molds with concrete, and rotating around the rotation axis.

[0006]

According to the above construction, the concrete filled in each of the gutter-shaped molds radially bound around the axis of rotation receives the centrifugal force generated by the rotation of the gutter-shaped molds, and thus the concrete is filled in the form. It is filled without gaps between the arranged reinforcing bars and is sufficiently compacted. As a result, concrete with high strength can be obtained.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT A preferred embodiment of the present invention will now be described with reference to FIG.
A method of manufacturing the half precast beam 100 having the structure as shown in FIG. 1 will be described with reference to FIGS.
First, FIG. 1 shows a reinforcing bar assembly process in which reinforcing bars are incorporated in a gutter-shaped form. A gutter-shaped form shown by reference numeral 10 in the drawing is a direction in which a pair of side plates 11a and a bottom plate 11b are orthogonal to the longitudinal direction. Form main body 11 combined in a gutter shape whose cross section is substantially U-shaped
And a weir plate 12 that closes both longitudinal ends (only one end is shown in the figure) of the mold body 11. Both side plates 11a of the mold body 11 are provided with a stepped portion 11d located in the vicinity of the opening 11c and extending in the longitudinal direction, and the barrier plate 12 has a concave inner portion formed substantially in the center thereof. Cotter forming part 12a
And a plurality of (four in the illustrated example) main-bar insertion holes 12b opened corresponding to the arrangement position of the main bar 21 near the bottom of the form body 11. Further, a reinforcing bar indicated by reference numeral 20 in the drawing is a plurality of (four in the illustrated example) beam lower end main bars 21 arranged in the longitudinal direction in the vicinity of the bottom portion 11c in the mold body 11.
And a plurality of frame-shaped ribs 22 which are arranged at a predetermined interval in the longitudinal direction and whose lower portion is connected to the beam lower end main ribs 21.

That is, in the bar arrangement process shown in FIG.
Reinforcing bars 20 arranged in the formwork main body 11 have both longitudinal ends of beam lower end main reinforcements 21 inserted into main reinforcement insertion holes 12b of a weir plate 12 fixed to both longitudinal ends of the formwork main body 11, respectively. Supported by. Although each rib 22 is temporarily fixed to and supported by a reinforcing bar arranged on the side of the opening 11c, it can be sandwiched between the wall surfaces on both sides of the opening 11c of the mold body 11.

FIG. 2 is a schematic perspective view showing a mold binding process for radially combining the gutter-shaped molds 10 and binding them, and the gutter-shaped molds 10 in which the reinforcing bars 20 are incorporated in the above-described process.
As shown in FIG. 2, a set of four pieces are arranged in a radial pattern of 90 ° equally distributed by a required number of binding members 30 such that the opening 11c of each mold body 11 is inside and the bottom plate 11b is outside. Be united in. The bundled gutter-shaped frame 10 is incorporated in a rotating device (not shown), and a concrete supply means 40 is arranged at the center of the radial shape where the openings 11c face each other.

FIG. 3 shows a gutter-shaped formwork 10 that is radially bound.
FIG. 3 is a schematic cross-sectional view showing a concrete pouring step of filling and rotating each of the concrete C by cutting in a direction orthogonal to the longitudinal direction of the gutter-shaped mold 10. That is, the gutter-shaped molds 10 that are radially bundled are rotated around the rotation axis O by the rotating device, and the concrete C is introduced into each gutter-shaped mold 10 through the concrete supply means 40 shown in FIG. Is filled. In addition, the filling amount of the concrete C in each gutter-shaped formwork 10 reaches a height exceeding the stepped portion 11d of the formwork main body 11 and does not fill the upper ends of the ribs 22 near the opening 11c. Is set.

The concrete C to be filled is kneaded with a small amount of water in order to obtain an extremely high strength and has a low softness at the time of pouring, but it has a large weight and is hard to rotate. Since a large centrifugal force is generated, the concrete C is filled between the complicated reinforcing bars 20 composed of the beam lower end main bars 21 and the ribs 22 arranged in the gutter-shaped form 10 without separating the material. And are joined closely. For this reason, a high-density placing state is achieved. In addition, the formwork body 1
The skin surface (upper surface) of the concrete C on the side of the opening 11c of No. 1 has a concave shape substantially along a surface having the same centrifugal force, that is, a cylindrical surface centering on the rotation axis O.

After the above-described rotation is performed for a predetermined time, the rotation by the rotating device is stopped, and the gutter-shaped frame 1 by the binding member 30 is
Release the binding of 0. In FIG. 4, the gutter-shaped formwork 1 in which the bundling has been released is left with the opening 11c facing upwards.
It is a perspective view which shows the process of curing the concrete C in 0. After a predetermined curing period required to develop high strength due to the hydration reaction of concrete C, both side plates 11a constituting the mold body 11 and the weir plates 12 at both ends of the mold body 11 are removed and removed. Mold.

FIG. 5 is a perspective view showing a half precast beam 100 formed through the above-mentioned steps. This half precast beam 100 is a frame frame where concrete is newly post-cast at the construction site.
It has a dense concrete structure due to being compacted by centrifugal force in the casting process, and has extremely high strength. The upper ends of the respective ribs 22 are exposed from the concave upper surface 101, the beam lower end main bars 21 are exposed from the lower ends of the longitudinal ends, and the gutter-shaped frame is formed at the central portions of the longitudinal ends. The cotter 102 corresponding to the cotter forming portion 12a of the barrier plate 12 of 10 is formed so as to project, so that the piecing joint with the post-cast concrete can be reliably performed. Step portions 11b on both sides of the form body 11
The shoulder portion 103 formed corresponding to is a joint portion with the slab and is firmly joined in a state where the edge of the slab is hooked. Further, on the upper surface 101, in order to ensure the joint with the post-cast concrete and to transmit the shearing force of the joint surface, a large number of uneven shear-shaped shear keys 104 arranged in the longitudinal direction at predetermined intervals as necessary. Is formed,
This shear key 104 is used in the bar arrangement process shown in FIG.
It can be formed in the vicinity of the opening 11c of the mold body 11 by incorporating a shear key forming mold material (not shown) in a comb shape.

The present invention is not limited to the illustrated embodiment. For example, the number of the bar bottom main bars 21 and the like in the reinforcing bar 20 and the reinforcing bar shape are the same as those of the half precast beam 1.
00 is arbitrarily determined according to the cross-sectional area of 00 and the reinforcement force to be obtained, and the number of gutter-shaped molds 10 to be bound in the form-binding step is also limited to the illustrated four equidistant shapes. Instead, for example, it is optional such as three equal distributions (120 ° even distribution) or six equal distributions (60 ° even distribution), and various binding members 30 can be considered.

[0015]

According to the method of manufacturing a half precast beam according to the present invention, concrete casting and compaction on a plurality of gutter-shaped molds are performed at the same time, so that a plurality of half precast beams can be manufactured at the same time. It is possible to perform compaction easily and precisely by using centrifugal force, even though ultra-high-strength concrete lacking workability is used, and the complexity of work can be eliminated. Is realized.

[Brief description of drawings]

FIG. 1 is a perspective view showing a reinforcing bar arrangement process according to an embodiment of the present invention.

FIG. 2 is a schematic perspective view showing a mold binding process in the above embodiment.

FIG. 3 shows the concrete placing step in the above embodiment,
It is a schematic sectional drawing cut and shown in a direction which intersects perpendicularly with a longitudinal direction of gutter shape frame 10.

FIG. 4 is a perspective view showing a state where the bundling of the gutter-shaped form is released and concrete is cured in the above-mentioned embodiment.

FIG. 5 is a perspective view showing a half precast beam obtained by the manufacturing method of the above-described embodiment.

[Explanation of symbols]

 10 Gutter-shaped formwork 11c Opening 20 Reinforcing bar 30 Bundling member C Concrete

Claims (1)

[Claims] 1. A reinforcing bar assembly process in which reinforcing bars are incorporated in a plurality of gutter-shaped molds, and the plurality of gutter-shaped molds are radially arranged around a rotation axis so that the openings are on the inner diameter side. Half pre-casting, which comprises a form tying process of tying and tying together, and a concrete pouring process of filling the plurality of gutter-shaped forms with concrete and rotating them around the rotation axis. Beam manufacturing method.