JP2010037911A - Joint structure of concrete member end - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a joint structure of a concrete member end capable of exhibiting superior structural performance and of reducing the fixing length of a concrete and a joining reinforcement. <P>SOLUTION: In this joint structure of a concrete member end, a beam side U-part 12 which is adopted at the joint part T between a beam 1 and a column 2 which is formed of precast members and which is formed in U-shape by extending reinforcements 11 disposed in the concrete body 10 of the beam 1 in the axial direction E outward from the joint end surface 1a of the concrete body 10 and by connecting the ends of the reinforcements 11 to each other and joining reinforcements 21 projecting from the side surface 2a of the column 2 toward the axial direction E of the beam 1 are arranged while being overlapped with each other in the axial direction E. A non-adhering district R which does not adhere to the concrete is provided in the overlapped district of a part of the joining reinforcements 21 near the column 2. The beam side U-part 12 is disposed in the non-adhering district R, and the concrete 4 is deposited between the beam 1 and the column 2. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a joint structure for an end portion of a concrete member.

  Conventionally, as a method of reducing damage such as cracking and crushing of the concrete after the main bar yields at the joint between a reinforced concrete column and beam, a reinforcing bar protruding from the side of the column and The main reinforcement of the beam is overlapped, and a part of the joining reinforcing bar near the column is covered with a sheath tube made of polyethylene, etc., so that the adhesion of the joining reinforcing bar and the concrete is eliminated and insulation is performed. There is a method of increasing the deformability and preventing adhesion split fracture due to adhesion with concrete (for example, see Patent Document 1).

Patent Document 1 uses a main reinforcement arranged in one concrete member and a joint reinforcement (joining rebar) arranged in the other concrete member, and the main reinforcement is at least a boundary between the other concrete member. In addition to arranging the bars to the surface, the joint bars are extended from the other concrete member to the inside of one concrete member and overlapped with the main reinforcement, and close to one concrete member in all the overlapping sections. A joint structure is disclosed in which a part of the section is attached to the concrete and a part of the section near the other concrete member is not attached to the concrete.
JP 2004-346541 A

However, the conventional joint structure of the end portion of the concrete member has the following problems.
That is, as in Patent Document 1, the joining structure in which a portion where adhesion with the concrete is eliminated by covering the joining rod of the column with a sheath tube or the like is other than the portion where the adhesion between the joining reinforcement and the concrete is eliminated. In addition, there is a disadvantage that a sufficient fixing length is required in the fixing portion between the joining reinforcing bar and the concrete, and the overlap length between the joining reinforcing bar and the main reinforcing rod becomes long. Therefore, when adopting the joining technique of Patent Document 1 and making one concrete member having a main bar in the material axial direction as a precast member made of precast concrete, the post-cast concrete portion of the joint becomes long and the amount of placement In this respect, there is room for improvement because the advantages of precasting such as simplified construction are reduced.

  The present invention has been made in view of the above-described problems, and provides a joint structure for the end of a concrete member that can exhibit excellent structural performance and can shorten the fixing length between concrete and a reinforcing bar for joining. For the purpose.

  In order to achieve the above object, in the joint structure of concrete member ends according to the present invention, the ends of the main bars arranged in the direction of the material axis in one of the concrete members to be joined to each other are connected. Then, the U-shaped portion formed in a U-shape and the joining rebar protruding from the peripheral surface of the other second concrete member in the material axis direction are arranged so as to overlap in the material axis direction, and the overlap The section is characterized in that a non-adhering section that does not adhere to concrete is provided in a part of the joining rebar close to the second concrete member, and the U-shaped portion is disposed in the non-adhering section.

  Moreover, in the joining structure of the concrete member edge part which concerns on this invention, one 1st concrete member is a precast member among the concrete members joined mutually, The main reinforcement arrange | positioned in the material axis direction in the precast member is precast. A U-shaped part that extends outward from the joint end surface of the member and connects the ends of its main bars to form a U-shape, and a joint projecting from the peripheral surface of the other second concrete member in the direction of the material axis Reinforcing bars are arranged so as to overlap in the material axis direction, and in the overlapping section, a non-adhering section that does not adhere to concrete is provided in a part near the second concrete member of the joining reinforcing bar, and the U-shaped part is not While arrange | positioning in an adhesion area, it is characterized by being configured by placing concrete between the precast member and the second concrete member.

In the present invention, since the non-adhering section where the reinforcing bars for joining the second concrete member do not adhere to the concrete is provided, when the first concrete member (precast member) is deformed and a bending moment is applied, the non-adhering section is provided. Since it yields in the adhesion section, it is possible to exhibit the elongation deformation performance of the first concrete member. Therefore, it is possible to deform the first concrete member while suppressing adhesion split fracture at the joint with the second concrete member.
In addition, since the end of the main reinforcement of the first concrete member is formed in a U shape, an oblique compression strut constrained by the concrete portion is formed in the U shape, and the bending moment of the beam can be reduced. The fixing length in the material axis direction other than the non-attachment section in the overlap section between the joining reinforcing bar and the U-shaped portion can be shortened.

Moreover, in the joining structure of the concrete member edge part which concerns on this invention, it is preferable to connect the edge parts of the reinforcing bar for joining, and to form in U shape.
In the present invention, the effect of oblique compression struts can be obtained also in the reinforcing bars for joining, the effect of reducing the bending moment of the beam can be further increased, and excellent structural performance can be obtained.

  According to the joint structure of the end portion of the concrete member of the present invention, since the oblique compression strut is formed by the U-shaped portion of the first concrete member, the bending moment of the first concrete member can be reduced, and the main reinforcement and It is possible to shorten the fixing length other than the non-adhering section in the overlapping section with the joining rebar, and to exhibit excellent structural performance. Therefore, for example, in the case where the first concrete member, which is one concrete member, is used as the precast member, the length of the U-shaped portion protruding from the joint end surface of the precast member can be shortened, and the first cast member is driven into the joint portion. The advantage is that it is possible to simplify the construction by reducing the amount of concrete.

A concrete member end joint structure according to a first embodiment of the present invention will be described below with reference to FIGS.
FIG. 1 is an exploded perspective view showing a schematic configuration of a joint structure between a beam and a column according to the first embodiment of the present invention, FIG. 2 is a longitudinal sectional view of the joint structure shown in FIG. 1, and FIG. 3 is shown in FIG. FIG. 4 is a longitudinal sectional view showing the structure of the beam, FIG. 5 is a longitudinal sectional view showing the structure of the column, and FIGS. 6A to 6C are views showing the joining process of the column beam. is there.

  As shown in FIG. 1, the concrete member end joint structure according to the first embodiment is a joint between a beam 1 which is one concrete member and a column 2 which is another concrete member in a reinforced concrete building. It is applied to the part (reference symbol T) and has a structure in which reinforcing bars (main reinforcing bar 11 and connecting reinforcing bar 21) protruded from the concrete members are joined together.

As shown in FIGS. 2 to 4, the beam 1 is a precast concrete precast member manufactured in advance in a factory or the like, for example, and a plurality of main bars 11, 11,... 10. Extending outward from the joint end faces 1a, 1a (see FIG. 6 (a)) on both sides, the ends 11a, 11a of the pair of upper and lower main bars 11, 11 are formed in a U shape on one joint end face 1a. It has a beam-side U-shaped part 12 (U-shaped part). That is, a plurality (here, five) of the beam-side U-shaped portions 12 are arranged at a predetermined interval in the width direction of the beam 1 (direction orthogonal to the material axis direction E).
Here, in FIG. 1, FIG. 2, and FIG. 4, only one (column side) joining end face 1a of both joining end faces of the beam 1 is shown.

  A plurality of stirrups 13, 13,... Bundled in a direction perpendicular to the material axis direction E so as to surround the main reinforcing bars 11 are arranged in the material axis direction E in the main reinforcement 11 and the beam side U-shaped portion 12 in the concrete body 10. It is arranged. In the beam 1 before joining, a plurality of stirrups 13, 13,... Provided on the beam-side U-shaped portion 12 are stored at positions close to the end face 1 a side, and are movable in the material axis direction E. ing.

  On the other hand, as shown in FIG. 2 and FIG. 5, the column 2 is provided with main bars (not shown) in the axial direction (vertical direction) and parallel to the main bar 11 of the beam 1 (in the material axis direction of the beam 1). E), a plurality of joining rebars 21, 21,... Protruding from the side surface 2a (circumferential surface) of the column 2 are arranged. And the column side U-shaped part formed in the U-shape similar to the beam-side U-shaped part 12 which connected end part 21a, 21a of a pair of upper and lower joining reinforcing bars 21 and 21 among those reinforcing bars 21 22 has a structure. The protruding length of the column-side U-shaped part 22 is shorter than the protruding length of the beam-side U-shaped part 12. Further, the column-side U-shaped portion 22 has the beam 1 so as to overlap with the plurality of beam-side U-shaped portions 12, 12,. Are arranged alternately at positions shifted in the width direction (direction orthogonal to the material axis direction E, left-right direction toward the plane of FIG. 3).

  The column-side U-shaped portion 22 is covered with a sheath tube 23 having a predetermined length at a position near the side surface 2 a of the column 2. The sheath tube 23 is for insulating the bonding rebar 21 and the concrete (reference numeral 4) shown in FIG. 3 from being attached, and a polyethylene material is used as the member. As shown in FIG. 2, a section in the material axis direction E where the sheath tube 23 is provided is defined as a non-adhering section R.

As shown in FIG. 2, the column beam joint T configured as described above has a beam-side U-shaped portion 12 with a predetermined overlap length in the material axis direction E of the beam 1 with respect to the column-side U-shaped portion 22. The joint structure is constructed by placing the precast beam 1 in an overlapped state facing the column 2 and placing concrete 4 at the joint T (between the beam 1 and the column 2). ing. Note that the position of the end of the beam-side U-shaped portion 12 is in the vicinity of the side surface 2 a of the column 2.
That is, the joint portion T has a structure in which the beam-side U-shaped portion 12 is disposed in the non-adhering section R, and the column-side U-shaped portion 22 does not adhere to the concrete 4 in the non-adhering section R. In this section, the beam-side U-shaped portion 12 and the column-side U-shaped portion 22 are attached to the concrete 4.

Next, the effect | action of the junction structure of the beam 1 and the pillar 2 comprised in this way is demonstrated.
As shown in FIG. 2, the structure is provided with a non-attachment section R in which the reinforcing bars 21 for the columns 2 are not attached to the concrete 4, so that when the beam 1 is deformed and a bending moment is applied, the non-attachment section R is attached. The elongation deformation performance of the beam 1 for yielding in the section R can be exhibited. Therefore, it is possible to deform the beam 1 while suppressing adhesion split fracture at the joint T with the column 2.

  Further, since the end portion of the main bar 11 of the beam 1 is formed in a U shape, an oblique compression strut constrained by the concrete 4 is formed in the beam side U shape portion 12 to reduce the bending moment of the beam 1. In addition, the fixing length in the material axis direction E other than the non-attachment section R in the overlap section between the joining reinforcing bar 22 and the beam-side U-shaped portion 12 can be shortened.

Next, the construction method of the joining structure of the beam 1 and the column 2 described above will be described based on the drawings.
As shown in FIG. 6A, first, at a position where the beam 1 in the column 2 joins, the joining reinforcing bar 22 extends in the material axis direction E of the beam 1 and protrudes to the end 21a (see FIG. 5). The column side U-shaped part 22 is formed. At this time, a sheath tube 23 having a predetermined length is placed on the joining rebar 21 of the column side U-shaped portion 22 near the side surface 2 a of the column 2.
In addition, the beam 1 which is a precast member manufactured in advance in a factory or the like is carried into the site.

  Then, as shown in FIG. 6 (b), the joining portion of the column 2 and the joining end face 1 a of the beam 1 are opposed to each other, and the beam side U-shaped portion 12 and the column side U-shaped portion 22 are arranged in the material axis direction E Arrange them in an overlapped state. Then, the stirrups 13, 13,... Housed on the joint end surface 1 a side of the beam 1 of the beam side U-shaped portion 12 are slid to the column 2 side in the material axis direction E and arranged at predetermined intervals, At that position, the main reinforcing bar 11 of the beam-side U-shaped part 12 and the joining reinforcing bar 21 of the column-side U-shaped part 22 are fixed together.

  Next, as shown in FIG. 6 (c), a main frame 11 and a reinforcing bar 21 which are arranged at a joint T between the concrete body 10 of the beam 1 and the column 2 are embedded in a formwork (illustrated). (Omitted) is installed, and concrete 4 is placed to complete the joint T.

As described above, in the joint structure at the end of the concrete member according to the first embodiment, since the diagonal compression strut is formed by the beam-side U-shaped portion 12 of the beam 1, the bending moment of the beam 1 is reduced. In addition, it is possible to shorten the fixing length other than the non-attached section R in the overlapping section between the main reinforcing bar 11 and the joining reinforcing bar 21, and exhibit excellent structural performance.
Therefore, even when the beam 1 is used as a precast member as in the present embodiment, the length of the beam-side U-shaped portion 12 protruding from the joining end surface 1a of the precast member can be shortened. The advantage that the construction amount can be simplified by reducing the amount of concrete placed on the portion T is obtained.

Next, other embodiments will be described with reference to the accompanying drawings. However, the same or similar members and parts as those of the above-described first embodiment are denoted by the same reference numerals, and description thereof is omitted. A configuration different from the embodiment will be described.
FIG. 7 is a longitudinal sectional view showing a schematic configuration of a joint structure between a beam and a column according to the second embodiment, which corresponds to FIG. 2, and FIG. 8 is a sectional view taken along line BB in FIG. It is.
As shown in FIGS. 7 and 8, the joint structure according to the second embodiment is a double structure in which two main bars 31 of the beam 3 are arranged in the vertical direction, and are arranged outside in the vertical direction. The ends of the main bars 31a and 31b are connected to form a U shape, and the ends of the main bars 31c and 31d arranged inside in the vertical direction are connected to form a U shape. Here, in FIG. 7, FIG. 8, the beam side U-shaped part (U-shaped part) arrange | positioned outside by the cross sectional view of the beam 3 is shown by the code | symbol 32A, and the beam side U-shaped part (U-shaped) arrange | positioned inside Part) is indicated by reference numeral 32B.

And the rebar 24 for the pillar 2 of this 2nd Embodiment forms the column side U-shaped part 25 (25A, 25B) corresponding to the beam side U-shaped part 32A, 32B of a double structure. . The positions of the other beam-side U-shaped portions 32A and 32B and the column-side U-shaped portions 25A and 25B, the configuration of the sheath tube 23, and the like are the same as those in the above-described first embodiment.
In the second embodiment, the beam-side U-shaped portion 32 and the column-side U-shaped portion 25 each have a double structure, so that the effect of reducing the bending moment of the beam 3 by the oblique compression struts is further exhibited. Can be made.

As mentioned above, although 1st and 2nd embodiment of the joining structure of the concrete member edge part by this invention was described, this invention is not limited to said embodiment, In the range which does not deviate from the meaning It can be changed as appropriate.
For example, in the first and second embodiments, in the beams 1, 3 and the column 2, a pair of main reinforcing bars positioned in the vertical direction or connecting reinforcing bars are connected to form a U shape. However, it is not limited to such a form, and a pair of main reinforcing bars located in the left-right direction (horizontal direction orthogonal to the material axis direction E) or connecting reinforcing bars are connected to form a U-shape. It may be a configuration.

The size of the beam 1 and the column 2, the cross-sectional shape, or the main bars 11 and 31, the number of bonding bars 21, the diameter dimension, the length dimension of the sheath tube 23, and other configurations are limited to the present embodiment. It can be arbitrarily set according to conditions such as the shape and load of the building.
Furthermore, as concrete 4 post-placed on site, fiber reinforced concrete or the like may be used as well as ordinary concrete.

It is a disassembled perspective view which shows schematic structure of the joining structure of the beam and pillar by the 1st Embodiment of this invention. It is a longitudinal cross-sectional view of the junction structure shown in FIG. It is the sectional view on the AA line shown in FIG. It is a longitudinal cross-sectional view which shows the structure of a beam. It is a longitudinal cross-sectional view which shows the structure of a pillar. (A)-(c) is a figure which shows the joining process of a column beam. It is a longitudinal cross-sectional view which shows schematic structure of the junction structure of the beam and pillar by this 2nd Embodiment, Comprising: It is a figure corresponding to FIG. It is the BB sectional view taken on the line shown in FIG.

Explanation of symbols

1, 3 beams (one concrete member)
1a End face 2 Column (the other concrete member)
2a Side surface (circumferential surface)
4 Concrete 11 Main reinforcement 12, 32 Beam side U-shaped part (U-shaped part)
21 and 24 Reinforcing bars 22 and 25 Column side U-shaped portion 23 Sheath tube E Material axial direction R Non-attachment section T Joint portion

Claims (3)

A U-shaped portion formed by connecting ends of main bars arranged in the direction of the material axis in one first concrete member among the concrete members to be joined together, and a circumference of the other second concrete member Reinforcing bars that protrude in the direction of the material axis from the surface are arranged so as to overlap in the direction of the material axis,
In the overlap section, a non-adhesion section that does not adhere to concrete is provided in a part near the second concrete member of the joining rebar,
The joint structure of the edge part of the concrete member characterized by arrange | positioning the said U-shaped part in the said non-attachment area. One of the concrete members to be joined to each other is a precast member, and the main bars arranged in the direction of the material axis in the precast member are extended outward from the joint end surfaces of the precast members, and the ends of the main bars The U-shaped part formed by connecting the parts together in a U-shape and the joining rebar protruding from the peripheral surface of the other second concrete member toward the material axis direction are overlapped in the material axis direction. Place and
In the overlap section, a non-adhesion section that does not adhere to concrete is provided in a part near the second concrete member of the joining rebar,
The U-shaped portion is disposed in the non-adhering section, and concrete is placed between the precast member and the second concrete member.   The joint structure of the end part of the concrete member according to claim 1 or 2, wherein end parts of the joining reinforcing bars are connected to form a U shape.

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