JP5649698B2 - Reinforced concrete members - Google Patents

Description

  The present invention relates to a reinforced concrete member. Specifically, the present invention relates to a joint of main bars and a bar arrangement structure of reinforced concrete members such as columns and beams.

2. Description of the Related Art Conventionally, in reinforced concrete column beam structures, columns and beam main bars are continuous in the vertical or horizontal axis direction to ensure the necessary rigidity and proof strength for long-term loads and short-term loads. However, in order to ensure the workability at the site, the reinforcing bars are set to a predetermined length, and after transporting the reinforcing bars to the site and arranging the bars, the reinforcing bars are joined by various joints.
In addition, from the past, in structural calculations, it has been the principle to join at locations where bending stress during earthquakes is small, so the pillar is near the center or about 1 m above the floor level considering workability. It is recommended to set the joint position.

In recent years, strengthening of reinforcing bars and concrete has progressed, and RC structures have been adopted for high-rise buildings or super-high-rise buildings. In such a building, for example, the same kind of reinforcing bars with higher strength or larger diameter than those of ordinary buildings are used for the main reinforcing bars of the columns, and these reinforcing bars are welded together, welded joints, or filled with mortar. They are joined by mechanical joints such as a screw type and a screw fixing type.
When using a mortar filling type joint, reinforcing bars are joined to each other by inserting reinforcing bars into both ends of the sleeve and filling the sleeve with mortar. On the other hand, when using a screw-fixed joint, rebars are inserted into both ends of the sleeve and joined by tightening screws attached to the sleeve.

  However, the mechanical joint described above is more expensive than the pressure-welded joint, and the sleeve diameter increases as the reinforcing bar diameter increases, which affects the workability such as the construction speed and the concrete filling property of the joint part. There is a case.

Then, the structure of the pillar which joins the main bars of the four corners of a pillar with a mechanical joint and abuts other main bars is proposed (refer to patent documents 1). In this structure, the butting positions of the main muscles are set to the same level, or alternately changed to a staggered pattern.
Also, a column structure has been proposed in which the main bars at the four corners of the column are joined by mechanical joints, the other main bars are brought into contact with each other, and additional bars are arranged on these other main bars (see Patent Document 2).
According to these proposals, only the main bars at the four corners of the column are joined by mechanical joints, so the number of joints can be reduced, so that not only the construction cost can be reduced, but also the concrete fillability of the joints is improved, and Can be improved.

JP 2004-131960 A JP 2007-132158 A

  However, in actual buildings, the position of the inflection point of the bending stress is not always constant, and the stress distribution is asymmetrical in the positive and negative directions, and it often shifts to the column head side or the column base side depending on the rigidity difference between the upper and lower floors. . In this case, depending on the bending stress at the time of the earthquake, excessive tensile force more than expected may be applied to the joined main bars, and the main bars may yield or the concrete in the joints may be damaged, so that the predetermined strength cannot be secured. .

  An object of this invention is to provide the member of a reinforced concrete structure which can ensure rational yield strength with respect to the stress at the time of an earthquake, improving a workability.

The reinforced concrete member according to claim 1 is a reinforced concrete member including a main reinforcing bar and a shear reinforcing bar, and the main reinforcing bars are arranged at four corners of a cross section of the member and joined by mechanical joints. It consists of a first main bar and a second main bar arranged in a state where the end portion is abutted at a predetermined position of the member, and the first main bar is thicker or thicker than the second main bar, and, Ri high strength der, the second main reinforcement is a reinforcing bar that changes in intensity in the longitudinal direction, the strength of the abutting portion of the second main reinforcement are low intensity compared to the portion near Column joints It is characterized by being.

Here, examples of the material of the main muscle include SD345, SD390, SD490, SD590, and SD685.
In addition, the nominal diameter of the main muscle includes, for example, D25, D29, D32, D35, D38, D41, and D51 in consideration of the size of the sleeve.
Further, when the second main bars are to be abutted, the end surfaces of the two reinforcing bars may be brought into contact with each other, or a gap may be formed between these end surfaces.

  According to the present invention, the first main muscle is thicker or thicker than the second main muscle and has a high strength, thereby increasing the ratio of the main bars to be joined and the tensile force borne by the first main muscle. Can be made larger than the tensile force borne by the second main muscle. Therefore, even if the bending stress becomes larger than expected at the time of an earthquake, the bending stress is surely maintained at the first main bar compared to the case where reinforcing bars with the same yield point and diameter are used for all main bars as in the past. There is no risk of yielding or breaking at the joint, and a reasonable yield strength can be secured against the stress at the time of the earthquake. As a result, it is not always necessary to provide the joint position near the inflection point.

Moreover, since only the 1st main reinforcement was joined by the mechanical joint, since a joint location can be reduced, not only the construction cost can be reduced, but also the filling property of the concrete in the joint portion can be ensured and the workability can be improved.
Further, in the configuration shown in Patent Document 2, there is a problem that it takes time to arrange the supplementary muscles. However, according to the present invention, since the second principal muscles are just abutted, conventional supplementary muscles are unnecessary. Therefore, it is possible to eliminate the bar arrangement and improve the workability.

  Moreover, if the reinforcing bars are pre-assembled on the ground, and the pre-assembled reinforcing bars are lifted by a crane and attached to a predetermined position, the construction speed can be improved.

Moreover, reinforced concrete member, said first main reinforcement is disposed at the four corners of cross section of the member, the second main reinforcement are preferably not joined together.

  According to this invention, since the first main bars are arranged at the four corners of the reinforced concrete members such as columns and beams, the bending stress can be effectively borne in both the X and Y directions in plan view. In addition, the second main reinforcing bar may be abutted at any position in consideration of the bending stress of the member, but if it is abutted at a location where only the main reinforcing material at the four corners can bear the required bending, the joining of the second main reinforcing bars is omitted. it can. Further, the main bars do not necessarily have to contact each other, and there may be a gap.

Further, in the reinforced concrete member, the second main reinforcing bar is a reinforcing bar whose strength changes in the length direction, and the butted portion of the second main reinforcing bar has a lower strength than the portion in the vicinity of the column beam joint. It is preferable .

In the configuration shown in Patent Document 1, if the abutting positions of the main bars are set to the same level, the abutting positions are aligned, and there is a possibility that the bending strength of the column is lowered at the abutting position. In addition, when the matching position of the main bars is staggered, there is a problem that it takes a lot of work.
Therefore, according to the present invention, the butting position of the second main bars is varied in the vertical direction on the two adjacent side surfaces of the column. Therefore, compared to the conventional case where the butting positions are aligned, it is possible to prevent the bending strength of the columns from being lowered at the butting position, and compared to the conventional case where the butting positions of the main bars are staggered. It does n’t take much work.

  It is preferable that the above-mentioned reinforced concrete member is a beam, and the butting position of the second main reinforcing bar differs in the horizontal direction on the upper and lower surfaces of the beam.

  By varying the butting position of the second main bar horizontally on the upper and lower surfaces of the beam, it is possible to prevent the bending strength of the beam from decreasing at the butting position, and to shift the butting position of the main bars one by one. Compared to the case, there is no need for reinforcement and construction.

  The above-mentioned reinforced concrete member is a beam having a through hole at the position of the mechanical joint, and it is preferable that opening reinforcing bars that connect the upper and lower bars are arranged on both sides of the through hole.

  A mechanical joint sleeve is arranged and a through hole is provided at a position where the rigidity is higher than other parts, and opening reinforcing bars are arranged on both sides thereof. Therefore, it is possible to prevent cracks and damage from being collected on both side portions of the joint portion where the stress tends to be discontinuous due to the difference in rigidity, and the design design and the degree of freedom of equipment piping are improved. As the opening reinforcing bars, outer peripheral shear reinforcing bars, core bars, or ties (connecting bars) that restrain the main bars at the four corners may be individually arranged.

  According to the present invention, the first main muscle is thicker or thicker than the second main muscle and has a high strength, thereby increasing the ratio of the main bars to be joined and the tensile force borne by the first main bars. It can be larger than the second main muscle. Therefore, even if the bending stress becomes excessive at the time of an earthquake, the tensile force due to bending can be more reliably borne by the first main bar than in the past, and it does not yield or break at the joint part. On the other hand, the yield strength can be reasonably secured. Further, it is not always necessary to provide the joint position near the inflection point. Moreover, since only the 1st main reinforcement was joined by the mechanical joint, not only a joint location can be reduced and construction cost can be reduced, but the filling property of the concrete of a joint part can also be improved.

It is a longitudinal section of a pillar as a reinforced concrete member according to an embodiment of the present invention. It is a cross-sectional view of the pillar which concerns on the said embodiment. It is a perspective view of the pillar which concerns on the said embodiment.

FIG. 1 is a longitudinal sectional view of a column 10 as a reinforced concrete member according to an embodiment of the present invention. FIG. 2 is a cross-sectional view of the column 10.
The column 10 is a quadrangular columnar column that extends in the vertical direction, and is joined to a column beam joint 20 positioned above the column 10 and a column beam junction 30 located below the column 10.
The four side surfaces of the pillar 10 are 10A, 10B, 10C, and 10D.

The column 10 includes a plurality of main bars 11 and 12 extending in the vertical direction, and a plurality of hoop bars 13 as shear reinforcement bars provided around the main bars 11 at predetermined intervals.
The main bars 11 and 12 are arranged between the four first main bars 11 arranged at the four corners of the cross section of the column 10 and two side bars 10A to 10D of the column 10 between the adjacent first main bars 11. And a total of eight second main muscles 12.

The first main reinforcing bar 11 has a diameter larger than that of the second main reinforcing bar 12, and an upper floor side reinforcing bar 111 and a lower floor side reinforcing bar 112 are joined by a mechanical joint 113. Specifically, the mechanical joint 113 has a cylindrical shape, and the end of the upper floor side reinforcing bar 111 is inserted into one end side of the mechanical joint 113, and the lower floor side has the other end side. The end of the reinforcing bar 112 is inserted.
On the other hand, the second main reinforcing bar 12 is a state in which the upper floor side reinforcing bar 121 and the lower floor side reinforcing bar 122 are in contact with each other, and are not joined to each other by welding or pressure welding.

From the viewpoint of workability, the joint position of the first main bar 11 and the butting position of the second main bar 12 are about 1 to 1.5 m above the floor level.
The butting positions of the second main bars 12 are different in the vertical direction on the two adjacent side surfaces of the column 10. Specifically, as shown in FIG. 3, the butting position of the second main reinforcing bars 12 arranged along the side surfaces 10A and 10C is on the upper side of the central portion of the column 10, but is arranged along the side surfaces 10B and 10D. The butted position of the second main muscle 12 is located below the central portion of the column 10.

  In addition, the second main reinforcing bar 12 is a reinforcing bar having a diameter smaller than that of the first main reinforcing bar and has a lower strength than the first main reinforcing bar, but may be a reinforcing bar having the same strength (yield point).

According to this embodiment, there are the following effects.
(1) By making the 1st main reinforcement 11 thicker than the 2nd main reinforcement 12, the ratio of the main reinforcement joined can be raised, the stress of a column main reinforcement is transmitted reliably, and the section in a joint position The bending strength of can be increased. Therefore, even if the bending stress is excessively greater than expected during an earthquake, the bending stress can be reliably borne by the first main bar 11 compared to the case where reinforcing bars of the same strength are used for all main bars as in the prior art. There is no risk of yielding or breaking at the part, and it is possible to reasonably secure the proof strength against the stress at the time of earthquake. As a result, it is not always necessary to provide the joint position near the inflection point.

Moreover, since only the 1st main reinforcement 11 was joined with the mechanical coupling 113, since a joint location can be reduced, not only the construction cost can be reduced, but the filling property of the concrete of a joint part can be ensured and workability can be improved.
Moreover, since only the 2nd main reinforcement 12 is faced | matched, the conventional supplementary reinforcement becomes unnecessary, the congestion of reinforcement arrangement | positioning is eliminated, and workability | operativity can be improved.

  (2) Since the first principal bars 11 are arranged at the four corners of the column 10, bending stress can be effectively borne in both the X and Y directions in plan view.

  (3) The butting position of the second main muscle 12 was varied in the vertical direction on the two adjacent side surfaces of the column. Therefore, it is possible to prevent the bending strength of the column 10 from being lowered at the abutting position compared to the conventional case where the abutting positions are aligned, and compared to the conventional case where the abutting positions of the main bars are staggered. It does not take much work.

  (4) Reinforcing bars whose strength changes in the length direction are prepared as the second main reinforcing bars 12, and the portion where the second main reinforcing bars 12 abut is lower in strength than the portions in the vicinity of the column beam joints 20 and 30. Arranged. Thereby, according to the bending stress which generate | occur | produces in the pillar 10, the 2nd main reinforcement 12 can be set to appropriate intensity | strength.

It should be noted that the present invention is not limited to the above-described embodiment, and modifications, improvements, etc. within a scope that can achieve the object of the present invention are included in the present invention.
In the present embodiment, the present invention is applied to the pillar 10, but the present invention is not limited to this, and the present invention may be applied to a beam. For example, it is possible to prevent the bending strength of the beam from being lowered at the abutment position by changing the abutment position of the second main bar in the horizontal direction on the upper and lower surfaces of the beam and to stagger the abutment position one by one. Compared to the case, there is no need for bar arrangement or construction.

In the present embodiment, the first main muscle 11 has a larger diameter than the second main muscle 12, but the present invention is not limited to this, and the material of the first main muscle 11 may be stronger than the second main muscle 12.
In the present embodiment, four first main bars 11 are arranged. However, the present invention is not limited to this, and five or more first main bars may be arranged.

10 Pillars 10A, 10B, 10C, 10D Sides of Pillar 11 First Main Bar 12 Second Main Bar 13 Hoop Bar (Shear Reinforcement Bar)
20, 30 Beam-column joints 111, 112, 121, 122 Reinforcing bars 113 Mechanical joints

Claims (1)

A reinforced concrete member comprising a main reinforcement and a shear reinforcement,
The main bars are arranged at the four corners of the cross section of the member, and are composed of a first main bar joined by a mechanical joint, and a second main bar arranged in a state where the end portion is abutted at a predetermined position of the member,
Said first main reinforcement, as compared to the second main reinforcement, large diameter or large diameter, and Ri high strength der,
The second main reinforcing bar is a reinforcing bar whose strength changes in the length direction,
A reinforced concrete member characterized in that the strength of the butted portion of the second main reinforcing bar is lower than that of the portion near the beam-column joint .

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