JP2021143464A - Column-beam connection structure - Google Patents

Abstract

To provide a column-beam connection structure capable of appropriately transmitting a large column axial force from an upper side high strength side column to a lower side high strength side column over a long period, while reducing the use of high-cost high strength side concrete and cost, and further, capable of appropriately transmitting a load transmitted from a low strength side beam to a connection part to the lower side high strength side column.SOLUTION: In a column-beam connection structure, upper and lower high strength side columns 1 formed of high strength side concrete are connected to a low strength side beam 2 formed of low strength side concrete at a connection part 4; inside the connection part 4, a through part 41 set between end parts of the respective high strength side columns 1 is formed of the high strength side concrete; a part 44 other than the through part 41 of the connection part 4 is formed of the low strength side concrete; the end part of each of the high strength side columns 1 is connected within a range of the upper and lower end faces of the through part 41; and load transmitting means 45 is provided for transmitting the load from the low strength side beam 2 to the through part 41.SELECTED DRAWING: Figure 1

Description

In the present invention, upper and lower high-strength side columns composed of high-strength side concrete having high concrete strength and low-strength side beams composed of low-strength side concrete having lower concrete strength than the high-strength side concrete are joints. It relates to the column-beam joint structure connected by the part.

In buildings where the columns are thinner than usual or in super high-rise buildings, the column axial force becomes large, so it is composed of ultra-high strength concrete such ^{that the design standard strength Fc, which is an example of concrete strength, exceeds 100 N / mm 2.} Pillars may be adopted.

Generally, in a beam-column structure of such a building, the columns are surrounded by upper and lower columns and lateral beams so that a large column axial force is appropriately transmitted from the upper column to the lower column. The joints are also made of ultra-high-strength concrete, but there is a problem that the amount of ultra-high-strength concrete used is high and the construction cost is high.

In this regard, Patent Document 1 describes upper and lower precast columns (corresponding to high-strength side columns) composed of ultra-high-strength concrete (corresponding to high-strength side concrete) and high-strength concrete (corresponding to low-strength side concrete). By burying a tubular reinforcing metal fitting inside the joint part surrounded by the precast beam (corresponding to the low-strength side beam) composed of, the joint part is not high-strength side concrete but low-strength side concrete. A column-beam joint structure composed of side concrete has been proposed.

Jikkenhei 5-24701A

In the beam-column joint structure described in Patent Document 1, the amount of high-strength side concrete, which is costly, can be reduced by using low-strength side concrete for the joint portion. However, even if the joint is reinforced with reinforcing hardware, the concrete strength of the joint is definitely lower than the concrete strength of the upper and lower high-strength side columns. Considering this, it is hard to say that the durability of the joint that receives a large compressive force between the upper and lower high-strength side columns is sufficient.

In view of this situation, the main problem of the present invention is to reduce the amount of costly high-strength side concrete used to reduce the cost, and from the upper high-strength side column to the lower high-strength side column. Provided is a column-beam joint structure capable of appropriately transmitting a column axial force over a long period of time and further appropriately transmitting a load transmitted from a low-strength side beam to a joint portion to a lower high-strength side column. At the point.

The first feature configuration of the present invention is a low-strength side composed of upper and lower high-strength side columns composed of high-strength side concrete having high concrete strength and low-strength side concrete having lower concrete strength than the high-strength side concrete. It is a column-beam joint structure in which the beam is connected at the joint.
Inside the joint, a through portion extending between the ends of the high-strength side columns connected to the top and bottom of the joint is made of the high-strength side concrete, and the through of the joint is formed. The parts other than the part are composed of the low-strength side concrete.
The ends of the high-strength side columns are connected within the range of the upper and lower end faces of the through portion.
A point is that a load transmitting means for transmitting a load transmitted from the low-strength side beam to a portion other than the through portion of the joint portion is provided to the through portion.

According to this configuration, the joint portion surrounded by the upper and lower high-strength side columns and the lateral low-strength side beams extends through the ends of the upper and lower high-strength side columns. Since the parts other than the part are composed of low-strength side concrete, the amount of high-strength side concrete, which is costly, can be reduced compared to the case where the entire joint is composed of high-strength side concrete, resulting in lower cost. Can be planned.
Moreover, since the ends of the high-strength side columns are connected within the range of the upper and lower end faces of the through portion composed of the high-strength side concrete, the column axial force is applied to the portion composed of the low-strength side concrete at the joint. A large pillar axial force is appropriately transmitted from the upper high-strength side pillar to the lower high-strength side pillar through a through portion composed of high-strength side concrete as well as the upper and lower high-strength side pillars. can do. Therefore, a large column axial force is applied from the upper high-strength side column to the lower high-strength side column for a long period of time without causing damage to the joint due to the compressive force received between the upper and lower high-strength side columns. Can be properly communicated over.
Further, since the load transmitted from the low-strength side beam to the portion other than the through portion of the joint portion is transmitted to the internal through portion by the load transmission means, the load is transmitted from the low-strength side beam to the portion other than the through portion of the joint portion. The transmitted load can also be appropriately transmitted to the lower high-strength side column through the through portion.

The second characteristic configuration of the present invention is that in the joint portion, the through portion is made of precast concrete.

According to this configuration, a through portion composed of high-strength side concrete such as ultra-high-strength concrete, which is difficult to construct on site, can be appropriately configured in a concrete factory or the like having dedicated equipment. Further, for example, even before constructing a part other than the low-strength side beam and the through portion of the joint at the construction site, a through portion made of precast concrete is installed in advance on the lower high-strength side column. It is also possible to build high-strength side columns on the upper side, and it is possible to adopt a flexible construction plan according to the situation.

The third characteristic configuration of the present invention is that the load transmitting means is a cotter formed on the outer peripheral portion of the through portion.

According to this configuration, when a through portion is manufactured in a concrete factory or the like, a cotter such as a groove is formed on the outer peripheral surface of the through portion, and low-strength side concrete is placed around the through portion arranged at a construction site or the like. It is possible to construct a load transmitting means capable of reliably transmitting the load transmitted from the low-strength side beam to the joint portion to the through portion only by placing the load without particularly crossing the joint reinforcing bar or the like.

The fourth characteristic configuration of the present invention is that the ends of the high-strength side columns are connected to the upper and lower end faces of the through portion by pin joining.

According to the present invention, since the end portion of the high-strength side column is connected to the through portion by pin joining, the high-strength side column composed of high-strength side concrete such as ultra-high-strength concrete which is particularly vulnerable to bending. It is possible to prevent the bending moment from acting on the end portion (column head or column base) as much as possible, and it is possible to suppress the destruction of the end portion of the high-strength side column in the event of an earthquake or the like.

Side sectional view showing a schematic structure of a beam-column joint structure Side sectional view of the main part of the beam-column joint structure Horizontal cross-sectional view of the main part of the beam-column joint structure

An embodiment of a beam-column joint structure according to the present invention will be described with reference to the drawings.
As shown in FIGS. 1 to 3, this beam-column joint structure corresponds to a column 1 (corresponding to a high-strength side column) composed of high-strength side concrete having high concrete strength in a beam-column structure of a reinforced concrete building. ) And the beam 2 (corresponding to the low-strength side beam) composed of the low-strength side concrete whose concrete strength is lower than that of the high-strength side concrete are placed in the joints 3 and 4 surrounded by the pillar 1 and the beam 2. To connect.

By the way, FIG. 1 shows a portion where the pillar 1 and the uppermost joint portion 3 are connected in the uppermost layer of the building, and the upper and lower pillars 1 and the intermediate layer joint portion 4 are connected in the middle layer of the building. The vertical cross section of the portion is schematically shown by omitting the reinforcing bars, and FIG. 2 shows in detail the vertical cross section of the portion of the intermediate layer of the building where the upper and lower columns 1 and the intermediate layer joint 4 are connected. ing. Further, FIG. 3 shows in detail the horizontal cross section of the portion of the intermediate layer of the building where the three beams 2 and the intermediate layer joint portion 4 are connected.

The column 1 is configured as a column thinner than usual by using ultra-high-strength concrete having ^{a design standard strength Fc of about 300 N / mm 2} as the high-strength side concrete. By being composed of high-strength side concrete, it becomes a pillar that is resistant to compression even if it is thin. However, on the other hand, since the column is vulnerable to bending, the details will be described later, but the joint between the end of the column 1 and the joints 3 and 4 is a pin joint that can avoid the bending moment as much as possible. NS.
As shown in FIG. 2, inside the column 1, a plurality of (4 columns in the illustrated example) column main bars 11 extending along the length direction of the column 1 in a state of being spaced in the circumferential direction of the column 1 are provided. A large number of band bars 12 arranged at a predetermined pitch in the length direction of the columns 1 are arranged so as to surround the plurality of column main bars 11.

The beam 2 is constructed by using high-strength concrete having ^{a design standard strength Fc of about 60 N / mm 2} as the low-strength side concrete.
As shown in FIG. 3, a plurality of beams 2 extend along the length direction of the beam 2 with a space between the upper end side and the lower end side in the beam width direction (four at the top and four at the bottom in the illustrated example). Eight) beam main bars 21 and a large number of stirrups 22 arranged at a predetermined pitch in the length direction of the beam 2 so as to surround the plurality of beam main bars 21 are arranged.

As shown in FIG. 1, in the uppermost layer joint 3 arranged in the uppermost layer of the building, the column 1 does not exist on the upper side, and only the load transmitted from the uppermost beam 2 is transmitted to the lower column 1. The whole is composed of the same low-strength side concrete as the beam 2.

On the other hand, the intermediate layer joint 4 arranged in the intermediate layer of the building transmits the load transmitted from the beam 2 of the intermediate layer to the column 1 on the lower side, and in addition, the column axis of the column 1 on the upper side. It is necessary to properly transmit the force to the lower pillar 1.

Therefore, the inside of the intermediate layer joint 4 is composed of the same high-strength side concrete as the upper and lower columns 1 and extends between the ends of the respective columns 1 connected to the upper and lower sides of the intermediate layer joint 4. A cylindrical through portion 41 is provided. The through portion 41 is provided in a state of extending over the upper and lower end faces at the central position of the intermediate layer joint portion 4 in a plan view.
Further, the end portions of the respective pillars 1 are connected within the range of the upper and lower end faces of the through portion 41. That is, the upper and lower end faces of the through portion 41 and the end portions of the respective pillars 1 are connected in a state where the contour of the end face of the pillar 1 is located inside the contour of the end face of the through portion 41 in a plan view.
Therefore, without applying a column axial force to the outer peripheral portion 44 other than the through portion 41 of the intermediate layer joint portion 4, the upper column is passed through the through portion 41 made of high-strength side concrete like the upper and lower columns 1. A large column axial force can be appropriately transmitted from 1 to the column 1 on the lower side.

In the present embodiment, the high-strength side concrete through portion 41 and the high-strength side concrete upper and lower pillars 1 are made of precast concrete. The through portion 41 and the pillar 1 made of high-strength side concrete such as ultra-high-strength concrete, which is difficult to construct on-site, can be appropriately configured in a concrete factory or the like having dedicated equipment. Further, for example, even before constructing the outer peripheral portion 44 other than the through portion 41 of the beam 2 and the intermediate layer joint portion 4 at the construction site, the lower pillar 1, the through portion 41, and the upper side made of precast concrete are formed. It is also possible to install the pillars 1 in this order, and a flexible construction plan can be adopted according to the situation.

As shown in FIGS. 2 and 3, a plurality of tip portions 11a of the plurality of column main bars 11 of the upper and lower columns 1 can be inserted into the inside of the through portion 41 of the intermediate layer joint portion 4 in a plan view. A plurality of metal sheath tubes 42 forming the vertical holes 42a (four in the illustrated example) are provided. The sheath tube 42 is provided over the upper and lower end faces of the through portion 41. Further, a large number of band bars 43 arranged at a predetermined pitch in the length direction of the column 1 are arranged so as to surround the plurality of sheath tubes 42. The pitch of the band bars 43 in the through portion 41 is set to the same pitch as the band bars 12 in the upper and lower columns 1.

Then, the tip end portion (protruding portion) 11a of the column main bar 11 of the upper and lower columns 1 is inserted into the opening of the vertical hole 42a on the upper and lower end faces of the through portion 41, and the vertical hole 42a is filled with a filler J such as grout. By doing so, the ends of the upper and lower pillars 1 are pin-joined to the upper and lower end faces of the through portion 41.

In the pin joining of the end portion of the column 1, an adhesive force reducing layer for reducing the adhesive force with the filler J is additionally provided on the outer peripheral surface of the tip end portion 11a of the column main bar 11 of the upper and lower columns 1. The adhesive force reducing layer is formed by, for example, wrapping a tape around the outer peripheral surface of the tip end portion 11a of the column main bar 11. Therefore, in the pin joining of the end portion of the column 1, the degree of fixation of the end portion of the column 1 can be further lowered, and the bending moment can be further suppressed from acting on the end portion of the column 1.
A gap for adjusting the posture is formed between the upper and lower end faces of the through portion 41 and the end faces of the respective pillars 1, and after the postures of the upper and lower pillars 1 are adjusted, the gap is also filled with a filler. J is filled.

The outer peripheral portion 44, which is a portion of the intermediate layer joint portion 4 other than the through portion 41, is made of the same low-strength side concrete as the beam 2, and the beam 2 is connected to the outer peripheral portion 44.
In FIG. 3, one X-direction beam 2A extending along the X direction in the plan view and two Y-direction beams 2B extending along the Y direction (vertical direction in the figure) orthogonal to the X direction in the plan view. , 2D is illustrated when it is connected to the outer peripheral portion 44 of the intermediate layer joint portion 4.

In the connection between the X-direction beam 2A and the outer peripheral portion 44 of the intermediate layer joint portion 4, as shown in FIG. 3, the tip portions 21a of the beam main bars 21 on both outer sides of the X-direction beam 2A in the beam width direction are the intermediate layer. It passes through both outer sides of the through portion 41 of the joint portion 4 and extends to a portion on the inner side of the outer peripheral portion 44 of the intermediate layer joint portion 4 and is buried. A fixing plate or the like is provided at the tip of the tip portion 21a of the beam main bar 21 on both outer sides in the beam width direction.
The tip portion 21b of the beam main bar 21 on the central side of the X-direction beam 2A in the beam width direction is the outer peripheral portion 44 of the intermediate layer joint portion 4 which is on the X-direction beam 2A side of the through portion 41 of the intermediate layer joint portion 4. It is embedded in a portion on the front side (X-direction beam 2A side of the through portion 41).

Further, in the connection between the Y-direction beams 2B and 2D arranged so as to sandwich the intermediate layer joint portion 4 from the Y direction and the outer peripheral portion 44 of the intermediate layer joint portion 4, the beam main bars 21 on both outer sides in the beam width direction are connected. Is common, and the beam main bars 21 on both outer sides in the beam width direction pass through both outer sides of the through portion 41 of the intermediate layer joint portion 4 and extend over the beams 2B and 2D in both Y directions. It is embedded in the outer peripheral portion 44 of the mouth portion 4.
The tip portion 21b of the beam main bar 21 on the central side of the Y-direction beam 2B in the beam width direction is embedded in a portion on the front side (Y-direction beam 2B side of the through portion 41) of the outer peripheral portion 44 of the intermediate layer joint portion 4. Will be done. Similarly, the tip portion 21b of the beam main bar 21 on the central side of the Y-direction beam 2D in the beam width direction is on the front side (Y-direction beam 2D side of the through portion 41) of the outer peripheral portion 44 of the intermediate layer joint portion 4. It is buried in the site.
Further, a loose bar 22 is embedded in the outer peripheral portion 44 of the intermediate layer joint portion 4 in an arrangement state in which it does not interfere with the through portion 41.

Then, as shown in FIGS. 1 to 3, in this beam-column joint structure, a load transmitting means 45 for transmitting the load transmitted from the beam 2 to the outer peripheral portion 44 of the intermediate layer joint portion 4 to the passing portion 41 is provided. Be done.
In the present embodiment, the outer peripheral portion 44 and the beam 2 of the intermediate layer joint portion 4 are made of cast-in-place concrete, whereas the load transmitting means 45 is formed on the outer peripheral surface of the through portion 41 made of precast concrete. It is composed of a groove-shaped cotter 45a. The cotters 45a are formed in an annular shape over the entire circumference of the outer peripheral surface of the through portion 41, and are provided in a plurality of cotters 45a in a state of being spaced apart in the vertical direction.

By engaging the inner peripheral surface of the outer peripheral portion 44 of the intermediate layer joint portion 4 with the outer peripheral surface of the through portion 41 inside the intermediate layer joint portion 4 via the cotter 45a, particularly across the joint reinforcing bars and the like. The load transmitted from the beam 2 to the outer peripheral portion 44 of the intermediate layer joint portion 4 can be reliably transmitted to the through portion 41 of the intermediate layer joint portion 4 without causing the beam 2. Therefore, the load transmitted from the beam 2 to the outer peripheral portion 44 of the intermediate layer joint portion 4 can also be appropriately transmitted to the lower column 1 through the through portion 41 of the intermediate layer joint portion 4.

For example, in the construction work for constructing a column-beam frame, a precast concrete through portion 41 is positioned at a predetermined position directly above the column 1 on the lower side, and the beam main bar 21 and the stirrups 22 and the stirrups 22 are formed around the through portion 41. By installing a formwork or the like and placing concrete, the cotter 45a is formed between the inner peripheral surface of the outer peripheral portion 44 of the intermediate layer joint portion 4 and the outer peripheral surface of the through portion 41 inside the intermediate layer joint portion 4. The outer peripheral portion 44 of the beam 2 and the intermediate layer joint portion 4 can be appropriately and easily constructed in the form of engaging the unevenness with the interposition.

Although not shown, even in the pin joining between the uppermost layer joint 3 and the lower column 1, an adhesive force reducing layer is provided on the outer peripheral surface of the tip 11a of the column main bar 11 of the lower column 1. be able to.

[Another Embodiment]
Other embodiments of the present invention will be described.
It should be noted that the configurations of the respective embodiments described below are not limited to being applied individually, but can also be applied in combination with the configurations of other embodiments.

(1) In the above embodiment, the high-strength side concrete is ^{an ultra-high-strength concrete having a design standard strength Fc of about 300 N / mm 2} , and the low-strength side concrete is a high-strength concrete having a design standard strength Fc of about ^{60 N / mm 2.} As an example, a certain case is shown, but the high-strength side concrete and the low-strength side concrete are concretes of various concrete strengths as long as the relative relationship that the high-strength side concrete has higher concrete strength than the low-strength side concrete is satisfied. There may be.

(2) In the above embodiment, as the load transmitting means 45 for transmitting the load transmitted from the beam 2 to the portion other than the through portion 41 of the intermediate layer joint portion 4 to the through portion 41, a groove-shaped cotter 45a is taken as an example. As shown, it may be a reinforcing bar or the like extending between a portion other than the through portion 41 of the intermediate layer joint portion 4 and the through portion 41.

(3) In the above embodiment, as an example, the through portion 41 of the intermediate layer joint portion 4 is made of precast concrete, and the portion other than the through portion 41 of the intermediate layer joint portion 4 is made of cast-in-place concrete. As shown, the entire intermediate layer joint portion 4 may be made of precast concrete. Further, in some cases, the entire intermediate layer joint portion 4 may be made of cast-in-place concrete.

(4) In the above-described embodiment, in the pin joining of the end portion of the column 1, the case where the adhesive force reducing layer is provided on the outer peripheral surface of the tip end portion 11a of the column main bar 11 of the column 1 is shown as an example. The reduction layer may not be provided.

1 pillar (high-strength side pillar)
2 beams (low-strength side beams)
4 Intermediate layer joint (joint)
4 Joint 41 Through part 44 Peripheral part (part other than through part)
45 Load transfer means 45a Cotter

Claims (4)

The upper and lower high-strength side columns made of high-strength side concrete with high concrete strength and the low-strength side beams made of low-strength side concrete with lower concrete strength than the high-strength side concrete are connected at the joint. It is a pillar-beam joint structure
Inside the joint, a through portion extending between the ends of the high-strength side columns connected to the top and bottom of the joint is made of the high-strength side concrete, and the through of the joint is formed. The parts other than the part are composed of the low-strength side concrete.
The ends of the high-strength side columns are connected within the range of the upper and lower end faces of the through portion.
A column-beam joint structure provided with a load transmitting means for transmitting a load transmitted from the low-strength side beam to a portion other than the through portion of the joint portion to the through portion. The column-beam joint structure according to claim 1, wherein in the joint portion, the through portion is made of precast concrete. The beam-column joint structure according to claim 2, wherein the load transmitting means is a cotter formed on the outer peripheral portion of the through portion. The column-beam joint structure according to any one of claims 1 to 3, wherein the ends of the high-strength side columns are connected to the upper and lower end faces of the through portion by pin joining.

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