JP7573397B2 - Pillar and beam joint structure - Google Patents

Description

The present invention relates to a joint structure between a pillar and a beam.

Traditionally, reinforced concrete beam-column frame structures have generally been designed to form yield hinges at the ends of beams to ensure the deformation performance of the beams. However, when beam reinforcement joints are provided in the hinge zones at the ends of beams, unexpected destruction may occur, or deformation performance or damage may deteriorate due to the effects of adhesion between the beam reinforcement and concrete, and the bearing pressure between the joint ends and the concrete.

There is a method of installing a reinforcing bar joint at a position that is more than half the length of the beam depth from the joint surface (beam end). In addition, the following Patent Document 1 proposes a hinge relocation method in which a cutoff bar is installed that penetrates the column and is embedded inside the beam, and a yield hinge is planned inside the beam span from the reinforcing bar joint.

JP 2015-17442 A

However, in the method of installing a reinforcing bar joint at a distance of more than half the beam depth from the joint surface, the position of the reinforcing bar joint is far from the joint surface, and this can result in a large portion of the post-cast concrete, particularly in the case of precast construction. In addition, the method described in Patent Document 1 requires a support plate at the end of the reinforcing bar to be cut off, and the length of the reinforcing bar limits the reduction in the area (length) of the post-cast concrete in the case of precast construction. For this reason, both methods have the problem of taking a long time to carry out on-site construction.

The present invention was made in consideration of the above circumstances, and provides a joint structure between a column and a beam that allows easy hinge relocation, which moves the hinge position of the beam from the joint surface to a position away from the beam side.

In order to achieve the above object, the present invention employs the following means.
That is, the column-beam joint structure according to the present invention is a column-beam joint structure in which a first beam and a second beam of reinforced concrete construction are joined to a column of reinforced concrete construction, the first beam and the second beam being arranged perpendicular to each other, and the first upper reinforcement is arranged in a slab arranged above the first beam and the second beam, on the outside of a first joint surface which is a joint surface facing the first beam side of the column, and a second upper reinforcement is arranged in the slab, on the outside of a second joint surface which is a joint surface facing the second beam side of the column, the first upper reinforcement being: The column has a first straight reinforcement portion extending along the extension direction of the second beam, and a downward portion bent downward from an end of the first straight reinforcement portion and having a tip portion arranged inside the first beam, and the second upper support reinforcement extends along the extension direction of the first beam, penetrates horizontally inside the column, and has a connecting beam main reinforcement that connects the column and the beam, the connecting beam main reinforcement and the beam main reinforcement provided on the beam are arranged coaxially, and the connecting beam main reinforcement and the beam main reinforcement are joined via a mechanical joint .

In a column-beam joint structure configured in this way, by providing the first upper reinforcement and the second upper reinforcement, hinge relocation can be performed to move the plastic hinge position to a position away from the column joint surface. Therefore, compared to the conventional method of providing a reinforcing bar joint at a position more than half the beam depth from the joint surface, or providing a cut-off bar that penetrates the column and is embedded inside the beam, the protruding length of the beam main reinforcement can be shortened, and the length of the cast-in-place concrete can be shortened, allowing for easy and efficient hinge relocation.

Furthermore, the column-beam joint structure of the present invention is a column-beam joint structure in which a first beam and a second beam of reinforced concrete construction are joined to a column of reinforced concrete construction perpendicular to each other, the joint structure comprising: a first upper splice bar arranged in a slab arranged above the first beam and the second beam, the first upper splice bar arranged on the outside of a first joint surface which is a joint surface facing the first beam side of the column; and a second upper splice bar arranged in the slab, the second upper splice bar arranged on the outside of a second joint surface which is a joint surface facing the second beam side of the column, the first upper splice bar is a U-shaped reinforcing bar with a curved portion arranged directly above the first beam, the second upper splice bar extends along the extension direction of the first beam, has a joint beam main bar that penetrates horizontally inside the column and connects the column and the beam, the joint beam main bar and the beam main bar provided in the beam are arranged coaxially, and the joint beam main bar and the beam main bar are joined via a mechanical joint .

In a column-beam joint structure configured in this way, by providing the first upper reinforcement and the second upper reinforcement, hinge relocation can be performed to move the plastic hinge position to a position away from the column joint surface. Therefore, compared to the conventional method of providing a reinforcing bar joint at a position more than half the beam depth from the joint surface, or providing a cut-off bar that penetrates the column and is embedded inside the beam, the protruding length of the beam main reinforcement can be shortened, and the length of the cast-in-place concrete can be shortened, allowing for easy and efficient hinge relocation.

The column-beam joint structure according to the present invention may also include a lower reinforcement bar that protrudes from the first joint surface and the second joint surface and is disposed inside the second beam, and the tip of the lower reinforcement bar may be bent upward.

In a column-beam joint structure constructed in this way, hinge relocation can be performed more reliably by providing a lower reinforcement.

The column-beam joint structure of the present invention makes it easy to perform hinge relocation, which moves the hinge position of the beam from the joint surface to a position away from the beam side.

1 is a schematic diagram showing a joint structure between a pillar and a beam according to a first embodiment of the present invention; FIG. 1 is a vertical cross-sectional view showing a joint structure between a column and a beam according to a first embodiment of the present invention. FIG. FIG. 4 is a schematic diagram showing a joint structure between a column and a beam according to a second embodiment of the present invention.

First Embodiment
A joint structure between a column and a beam according to a first embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a schematic diagram showing a joint structure between a column and a beam according to a first embodiment of the present invention.
As shown in Fig. 1, in the column-beam joint structure 10 of this embodiment, a column 1 made of reinforced concrete is joined to a beam 2 made of reinforced concrete. In this embodiment, beams 2 (beam (first beam) 2A, beam (first beam) 2B, beam (second beam) 2C) are joined to the column 1 from three directions. A slab 3 (see Fig. 2; the same applies below) is arranged above the beam 2.

Here, the extension direction of beams 2A and 2B, which are arranged coaxially with each other, may be referred to as the X direction. The extension direction of beam 2C, which extends in a direction perpendicular to the extension direction of beams 2A and 2B, may be referred to as the Y direction.

The column 1 is a precast concrete member having a rectangular column shape. The column 1 has a number of main column reinforcements 11, a column concrete section 12, and a number of tie bars (not shown). The column main reinforcements 11 extend in the vertical direction. The column main reinforcements 11 and tie bars are embedded in the column concrete section 12.

The beam 2 has a beam member 20. The beam member 20 is a precast concrete member having a rectangular column shape.

The beam member 20 has a plurality of beam main reinforcements 21, a plurality of stirrup reinforcements 22, and a beam concrete section 23. The beam main reinforcements 21 extend along the extension direction of each beam 2. The beam main reinforcements 21 are embedded in the beam concrete section 23. The tip of the beam main reinforcements 21 protrudes from the end face 23d of the beam concrete section 23 (the end face facing the column 1).

The stirrups 22 are arranged to surround the multiple beam main reinforcements 21. The upper parts of the stirrups 22 and the upper beam main reinforcements 21u of the multiple beam main reinforcements 21 protrude from the beam concrete portion 23 and are embedded in the slab concrete portion 32 of the slab 3 (see FIG. 2; the same applies below). The other parts of the stirrups 22 and the beam main reinforcements 21 other than the upper beam main reinforcements 21u are embedded in the beam concrete portion 23.

FIG. 2 is a vertical cross-sectional view showing a joint structure 10 between a column and a beam.
2 , the slab 3 is disposed on the upper side of the beam 2. The slab 3 has a plurality of slab reinforcements (not shown) and a slab concrete portion 32.

The multiple slab reinforcements are arranged along horizontal directions such as the X and Y directions. The multiple slab reinforcements and the upper beam reinforcement 21u are embedded in the slab concrete section 32, which is formed into a plate shape along the horizontal surface.

As shown in FIG. 1, the column-beam joint structure 10 includes a plurality of first joint beam main bars 41, a plurality of second joint beam main bars 43, a plurality of first upper support bars 51, a plurality of second upper support bars 52, a plurality of lower support bars 53, and a joint concrete section 54 (see FIG. 2; the same applies below).

The first joint beam main bar 41 penetrates the inside of the column 1 and protrudes from the joint surface 16 of the column 1 toward the beam 2. Specifically, the first joint beam main bar 41A extending in the X direction protrudes toward the beam 2A side from the joint surface (first joint surface) 16A facing the beam 2A side, and protrudes toward the beam 2B side from the joint surface (first joint surface) 16B facing the beam 2B side. The first joint beam main bar 41B extending in the Y direction protrudes toward the beam 2C side from the joint surface (second joint surface) 16C facing the beam 2C side. The first joint beam main bar 41 may be made of normal strength reinforcing bars or may be made of high-strength reinforcing bars.

In this embodiment, the first joint beam main bar 41 is arranged at a position corresponding to the beam main bar 21 and coaxially with the beam main bar 21. The end of the first joint beam main bar 41 is joined to the end of the beam main bar 21 via a reinforcing bar joint 42 such as a coupler.

The second joint beam main reinforcement 43 penetrates the inside of the column 1 and protrudes from the joint surface 16 of the column 1 toward the beam 2. Specifically, the second joint beam main reinforcement 43A extending in the X direction protrudes from the joint surface 16A toward the beam 2A side, and from the joint surface 16B toward the beam 2B side. The second joint beam main reinforcement 43B extending in the Y direction protrudes from the joint surface 16C toward the beam 2C side. The second joint beam main reinforcement 43B is positioned at a higher position than the second joint beam main reinforcement 43A.

In this embodiment, the second joint beam main bar 43 is arranged at a position corresponding to the upper beam main bar 21u and coaxially with the upper beam main bar 21u. The end of the second joint beam main bar 43 is joined to the end of the upper beam main bar 21u via a reinforcing bar joint 44 such as a coupler.

The first upper reinforcement bar 51 is L-shaped. The first upper reinforcement bar 51 has a first straight reinforcement bar portion 51a and a bent reinforcement bar portion (downward portion) 51b.

The first straight bar portion 51a extends along the extension direction of the beam 2C. The first straight bar portion 51a is positioned closer to the column 1 than the end face 23d of the beam concrete portion 23. When viewed from the Y direction, the first straight bar portion 51a is positioned outside and above the depth direction of the beam 2C. The first straight bar portion 51a is positioned along the outside of the joint faces 16A, 16B of the column 1. The first straight bar portion 51a is embedded in the slab concrete portion 32 of the slab 3.

The bent reinforcement section 51b is bent downward from the end of the first straight reinforcement section 51a. The upper part of the bent reinforcement section 51b is embedded in the slab concrete section 32 of the slab 3, and the remaining part of the bent reinforcement section 51b is embedded in the joint concrete section 54 described below.

In this embodiment, the first upper reinforcement bars 51 are arranged in pairs on the outside of the joint faces 16A and 16B of the column 1, spaced apart in the X direction. The number of first upper reinforcement bars 51 can be set as appropriate.

The second upper reinforcement bar 52 is formed in a straight line. The second upper reinforcement bar 52 extends along the extension direction of the beams 2A and 2B. The second upper reinforcement bar 52 is arranged outside the joint surface 16C of the column 1. The second upper reinforcement bar 52 is arranged below the second joint beam main reinforcement bar 43 (at the same height as the upper beam main reinforcement bar 21u extending in the X direction). The length of the second upper reinforcement bar 52 is longer than the width of the column 1 (length in the X direction). When viewed from the Y direction, the end of the second upper reinforcement bar 52 does not reach the end surface 23d of the beam concrete part 23. The second upper reinforcement bar 52 is embedded in the slab concrete part 32 of the slab 3.

In this embodiment, three second upper reinforcement bars 52 are arranged on the outside of the joint surface 16C of the column 1, spaced apart in the Y direction. The number of second upper reinforcement bars 52 can be set as appropriate.

The lower reinforcement bar 53 is L-shaped. The lower reinforcement bar 53 has a lower straight reinforcement bar portion 53a and a bent reinforcement bar portion 53b.

The lower reinforcement bar 53 penetrates the inside of the column 1 and protrudes from the joint surface 16 of the column 1 toward the beam 2. Specifically, the lower reinforcement bar 53A extending in the X direction protrudes from the joint surface 16A toward the beam 2A side. The lower reinforcement bar 53B extending in the X direction protrudes from the joint surface 16B toward the beam 2B side. The lower reinforcement bar 53C extending in the Y direction protrudes from the joint surface 16C toward the beam 2C side. The lower reinforcement bar 53A and the lower reinforcement bar 53B are joined inside the column 1 and may be a single reinforcing bar.

The lower straight bar portion 53a extends along the extension direction of the beam 2. The lower straight bar portion 53a is disposed inside the column 1 and protrudes from the joint surface 16. The lower straight bar portion 53a is disposed above the first joint beam main bar 41.

The bent reinforcement section 53b is bent upward from the end of the lower straight reinforcement section 53a. The portion of the lower straight reinforcement section 53a that protrudes from the joint surface 16 of the column 1 and the bent reinforcement section 53b are embedded in the joint concrete section 54 described below.

In this embodiment, three lower reinforcement bars 53 are arranged on each of the beams 2A, 2B, and 2C sides, spaced apart in the depth direction of the beam 2. The number of lower reinforcement bars 53 can be set as appropriate.

As shown in FIG. 2, the joint concrete section 54 is cast-in-place concrete. The joint concrete section 54 is concrete filled in the area from the end surface 23d of the beam concrete section 23 to the joint surface 16 of the column 1 at a height approximately equal to the height of the beam concrete section 23.

The portion from the end face 23d of the beam concrete section 23 to the joint face 16 of the column 1 (the joint concrete section 54 and the reinforcing bar embedded in the joint concrete section 54) is configured as part of the beam 2 and may be referred to as the beam joint section 2X (see Figure 2; the same applies below).

In the column-beam joint structure 10 configured in this way, by providing the first upper reinforcement 51 and the second upper reinforcement 52, hinge relocation can be performed to move the plastic hinge position to a position away from the joint surface 16 of the column 1. Therefore, compared to the conventional case where a reinforcing bar joint is provided at a position away from the joint surface by a length of 1/2 or more of the beam depth dimension, or a cut-off bar is provided that penetrates the column and is embedded inside the beam, the length of the cast-in-place concrete (the length of the joint concrete part 54 of the beam joint part 2X) can be shortened by shortening the protruding length of the beam main reinforcement 21 from the end surface 23d of the beam concrete part 23, and therefore hinge relocation can be performed easily and with good workability.

In addition, by providing a lower support brace 53, hinge relocation can be performed more reliably.

Second Embodiment
Next, a joint structure between a column and a beam according to a modified example of the second embodiment of the present invention will be described mainly with reference to FIG.
In the following embodiments, the same members as those used in the above-described embodiments are designated by the same reference numerals, and the description thereof will be omitted.

FIG. 3 is a schematic diagram showing a joint structure between a column and a beam according to a second embodiment of the present invention.
As shown in Figure 3, in this embodiment, the joint structure 10A between a column and a beam includes a plurality of first joint beam main reinforcements 41, a plurality of second joint beam main reinforcements 43, a plurality of first upper support reinforcements 55, a plurality of second upper support reinforcements 52, a plurality of lower support reinforcements 53, and a joint concrete section 54 (see Figure 2; the same applies below).

The first upper reinforcement bar 55 is a U-shaped reinforcing bar. The first upper reinforcement bar 55 is arranged along the outside of the joint faces 16A and 16B of the column 1.

The first upper support bar 55 has a pair of straight bar sections 55a and a curved bar section (curved portion) 55b. The straight bar sections 55a extend along the extension direction of the beam 2C. The pair of straight bar sections 55a are spaced apart in the X direction. The straight bar sections 55a are located closer to the column 1 than the end face 23d of the beam concrete section 23. When viewed from the Y direction, the straight bar sections 55a are located outside and above the depth direction of the beam 2C (at the same height as the upper beam main bar 21u extending in the Y direction). The straight bar sections 55a are located outside the joint faces 16A and 16B of the column 1. The straight bar sections 55a are embedded in the slab concrete section 32 of the slab 3.

The curved reinforcement section 55b connects the ends of a pair of first upper reinforcement bars 55 and is curved. The curved reinforcement section 55b is located directly above the beam joint 2X of the beams 2A and 2B (at the same height as the upper beam main reinforcement bar 21u extending in the Y direction). The curved reinforcement section 55b is embedded in the slab concrete section 32 of the slab 3.

In this embodiment, the first upper reinforcement bars 55 are placed on the outside of each of the joint faces 16A and 16B of the column 1. The number of first upper reinforcement bars 55 can be set as appropriate.

In the column-beam joint structure 10A configured in this way, the provision of the first upper reinforcement 55 and the second upper reinforcement 52 allows hinge relocation to be performed, in which the plastic hinge position is moved away from the joint surface 16 of the column 1. Therefore, compared to the conventional method of providing a reinforcing bar joint at a distance of 1/2 or more of the beam depth from the joint surface, or providing a cut-off reinforcement that penetrates the column and is embedded inside the beam, the length of the cast-in-place concrete (the length of the joint concrete portion 54 of the beam joint portion 2X) can be shortened by shortening the protruding length of the beam main reinforcement 21 from the end surface 23d of the beam concrete portion 23, and this allows hinge relocation to be performed easily and with good workability.

The assembly procedures and the shapes and combinations of the components shown in the above-mentioned embodiments are merely examples, and may be modified in various ways based on design requirements, etc., without departing from the spirit of the present invention.

For example, in the embodiment shown above, the joint structure 10 between the column and the beam is provided with the lower reinforcement bar 53, but the present invention is not limited to this. The joint structure 10 between the column and the beam does not have to be provided with the lower reinforcement bar 53.

In addition, in the embodiment shown above, the beam members 20 of the columns 1 and beams 2 are precast concrete members, but the present invention is not limited to this. The entire columns and beams may be made of reinforced concrete cast in place.

In addition, in the embodiment shown above, beams 2A, 2B, and 2c are joined to column 1, but the present invention is not limited to this. Beams 2A and 2C (or beams 2B and 2C) that are perpendicular to each other may be joined to column 1.

1...Column 2...Beam 2A...Beam (first beam)
2B…Beam (first beam)
2C…Beam (second beam)
2X... Beam joint 3... Slab 10, 10A... Joint structure between column and beam 11... Column main reinforcement 11
12... Pillar concrete part 16... Joint surface 16A... Joint surface (first joint surface)
16B… Joint surface (first joint surface)
16C… Joint surface (second joint surface)
20... Beam member 21... Beam main bar 21u... Upper beam main bar 22... Stirrup 23... Beam concrete section 32... Slab concrete section 41... First joint beam main bar 43... Second joint beam main bar 51... First upper splint 51a ...First straight muscle portion 51a
51b...Bending portion (downward portion)
52...Second upper reinforcement bar 53...Lower reinforcement bar 53a...Lower straight reinforcement bar portion 53b...Bent reinforcement bar portion 54...Concrete joint portion 55...First upper reinforcement bar 55a...Straight reinforcement bar portion 55b...Curved reinforcement bar portion (curved portion)

Claims (4)

A column-beam joint structure in which a first beam and a second beam of reinforced concrete structure are joined to a column of reinforced concrete structure so as to be perpendicular to each other,
A first upper reinforcement is arranged on the outer side of a first joint surface, which is a joint surface facing the first beam side of the column, in a slab arranged on the upper side of the first beam and the second beam;
A second upper reinforcement is provided in the slab and arranged on the outside of a second joint surface which is a joint surface facing the second beam side of the column,
The first upper reinforcement bar is
A first rectilinear portion extending along the extension direction of the second beam;
A downward portion is bent downward from an end of the first straight portion and has a tip portion disposed inside the first beam,
The second upper reinforcement extends along the extension direction of the first beam ,
A joint beam main bar is provided which penetrates the inside of the column in the horizontal direction and connects the column and the beam,
A joint structure between a column and a beam, characterized in that the joint beam main bar and the beam main bar provided on the beam are arranged coaxially, and the joint beam main bar and the beam main bar are joined via a mechanical joint . The upper portion of the downward portion is embedded in the slab concrete portion of the slab,
2. A column-beam joint structure according to claim 1, wherein a lower portion of the downward portion is embedded in a joint concrete portion provided between the column and the beam. A column-beam joint structure in which a first beam and a second beam of reinforced concrete structure are joined to a column of reinforced concrete structure so as to be perpendicular to each other,
A first upper reinforcement is arranged on the outer side of a first joint surface, which is a joint surface facing the first beam side of the column, in a slab arranged on the upper side of the first beam and the second beam;
A second upper reinforcement is provided in the slab and arranged on the outside of a second joint surface which is a joint surface facing the second beam side of the column,
The first upper support bar is a U-shaped reinforcing bar, and a curved portion is disposed directly above the first beam;
The second upper reinforcement extends along the extension direction of the first beam ,
A joint beam main bar is provided which penetrates the inside of the column in the horizontal direction and connects the column and the beam,
A joint structure between a column and a beam, characterized in that the joint beam main bar and the beam main bar provided on the beam are arranged coaxially, and the joint beam main bar and the beam main bar are joined via a mechanical joint . A lower reinforcement bar protruding from the first joint surface and the second joint surface and disposed inside the second beam is provided.
The column-beam joint structure according to any one of claims 1 to 3 , wherein the tip of the lower reinforcement is bent upward.

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