JP2017222993A - Column-beam junction structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure that prevents the destruction of a column-beam junction caused by deterioration of adhesion between concrete and a main reinforcement.SOLUTION: A column-beam junction structure includes a junction 10 having an arranged column main reinforcement 22 of a reinforced concrete column 20 and an arranged beam main reinforcement 32 of a reinforced concrete beam 30, and a bearing member (mechanical joint 40) to produce a bearing force, disposed on the column main reinforcement 22 or the beam main reinforcement 32.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a joint structure of column beams.

  In the column beam joint structure disclosed in Patent Document 1, fiber reinforcing material is mixed into the concrete cast in the column beam joint (column beam joint) to improve the strength of the concrete.

Japanese Patent Laid-Open No. 10-8551

  However, even if the strength of the concrete is improved, if the bending strength ratio between the column and the beam is small, the bending yield of the beam will occur at an early stage, and then the main bar yield will progress into the joint, resulting in a deterioration in the adhesion between the main bar and the concrete. May occur and the joint may be destroyed.

  In view of the above fact, an object of the present invention is to suppress the destruction of the joint portion of the column beam due to the deterioration of the adhesion between the concrete and the main reinforcement.

  The column beam joint structure according to claim 1 is provided with a joint portion in which a column main bar of a reinforced concrete column and a beam main bar of a reinforced concrete beam are arranged, and a support pressure provided on the column main bar or the beam main bar. A bearing member to be generated.

  In the joint structure of the column beam according to claim 1, when a tensile force is applied to the beam main bar or the column main bar, it resists by the support pressure generated in the support member and the adhesion between the beam main bar or the column main bar and the concrete. Therefore, the slip amount of the beam main bar or column main bar with respect to the concrete decreases. Thereby, the crack of the junction part accompanying the adhesive force deterioration of concrete and a main reinforcement can be suppressed. Therefore, destruction of the joint part of the column beam is suppressed.

  The joint structure of the column beam according to claim 2 is a mechanical joint in which the bearing member is provided at the joint or outside the joint.

  In the column beam joint structure according to the second aspect, when a tensile force acts on the beam main bar or the column main bar, a supporting pressure can be obtained from the small opening (end face) of the mechanical joint. Further, the mechanical joint can be easily attached to the column main bar and the beam main bar.

  In the column beam joint structure according to claim 3, the bearing member is a mechanical fixing tool, and the bearing generation surface is located at the center of the joint of the beam main bar.

  In the beam-column joint structure according to claim 3, when a tensile force is applied to the beam main bar or the column main bar, the beam is supported from the corner of the joint toward the opposite corner and at the center of the joint. A plurality of compression strads (compression bundles) are generated from the pressure generating surface toward the corners of the joint, and the yield strength of the joint is improved.

  The column beam joint structure according to claim 4, wherein when the supporting member is provided on the column main bar, the beam main bar intersects in an X shape, and the supporting member is provided on the beam main bar. In this case, the column main bars intersect in an X shape.

  In the joint structure of the column beam according to the fourth aspect, the beam main bars or the column main bars can be crossed in an X shape to resist an oblique tensile force acting on the joint. For this reason, the diagonal crack which generate | occur | produces in a junction part can be suppressed.

  In the joint structure of the column beam according to claim 5, the supporting member is provided on the column main bar, and a shear reinforcement bar is wound around the beam main bar.

  In the column beam joint structure according to claim 5, instead of wrapping the shear reinforcement bars around the column main bars, the shear reinforcement bars are wound around the beam main bars. For this reason, when a supporting pressure acts on a junction part from a bearing member, it can control that a beam main bar displaces to the outside of a junction part.

  The column beam joint structure according to claim 6 includes a joint portion in which a column main bar of a reinforced concrete column and a beam main bar of a reinforced concrete beam are arranged, and the column main bar of the joint portion is a column main bar of the column portion. The diameter is larger.

  In the beam-column joint structure according to claim 6, by making the diameter of the column main reinforcement of the connection portion larger than the diameter of the column main reinforcement of the column part, the adhesion stress input to the concrete is reduced, and the oblique crack of the concrete Is suppressed. Moreover, since the yield strength of the column main reinforcement at the joint is increased, the column beam bending strength ratio is increased.

  ADVANTAGE OF THE INVENTION According to this invention, destruction of the junction part of a column beam accompanying the adhesive force deterioration of concrete and a main reinforcement can be suppressed.

(A) is sectional drawing which shows the junction part of the column beam to which the junction part structure of the column beam which concerns on 1st Embodiment of this invention was applied, (B) is a mechanical coupling member provided in the beam main reinforcement. It is a perspective view shown. (A) is sectional drawing which shows the junction part of the column beam to which the junction part structure of the column beam which concerns on 2nd Embodiment of this invention was applied, (B) is a beam joined to the one side of the column in (A). It is sectional drawing which shows the done example. It is sectional drawing which shows the junction part of the column beam to which the junction part structure of the column beam which concerns on 3rd Embodiment of this invention was applied. (A) is sectional drawing which shows the junction part of the column beam to which the junction part structure of the column beam which concerns on 4th Embodiment of this invention was applied, (B) is a beam joined to the one side of the column in (A). It is sectional drawing which shows the done example. It is sectional drawing which shows the junction part of the column beam to which the junction part structure of the column beam which concerns on 5th Embodiment of this invention was applied. (A) is sectional drawing which shows the junction part of the column beam to which the junction part structure of the column beam concerning 6th Embodiment of this invention was applied, (B) is a mechanical fixing tool fixed to the beam main reinforcement. FIG. It is sectional drawing which shows the junction part of the column beam to which the junction part structure of the column beam which concerns on 7th Embodiment of this invention was applied. (A) is sectional drawing which shows the junction part of the column beam to which the junction part structure of the column beam which concerns on 8th Embodiment of this invention was applied, (B) is scattered in the junction part of a column beam in (A). It is sectional drawing which shows the example by which the streak was arranged.

[First Embodiment]
(Constitution)
As shown in FIG. 1 (A), the column beam joint structure according to the first embodiment is applied to a joint (joint part) 10 between a reinforced concrete column 20 and a reinforced concrete beam 30. The concrete forming the joint 10, the column 20, and the beam 30 is a cast-in-place concrete, and the column main bar 22 and the beam main bar 32 are arranged in the joint 10.

  Specifically, the column main reinforcement 22 of the column 20 penetrates the joint portion 10 in the vertical direction (substantially vertical direction), and the end portion of the beam main reinforcement 32 of the beam 30 is embedded in the joint portion 10 in the joint portion 10. Connected by a mechanical joint 40. The mechanical joint 40 is an example of a bearing member in the present invention.

  In addition, the junction part 10 is a part from the upper end surface of the beam 30 in the pillar 20 to a lower end surface, and in the following description, parts other than the junction part 10 in the pillar 20 are called pillar part 20A.

  As shown in FIG. 1B, the mechanical joint 40 is formed of a steel material having rigidity higher than that of the column main reinforcement 22, and the bearing portion area of the mechanical joint 40 (the end surface 40E of the mechanical joint 40 is in contact with the concrete C). The area) is set to be three times or more the cross-sectional area of the beam main bar 32. In other words, R ≧ 3.0, where R is the bearing area ratio between the mechanical joint 40 and the beam main bar 32 (= the bearing area of the mechanical joint 40 / the cross-sectional area of the beam main bar 32).

  Hoop bars (shear reinforcement bars) 24 are wound around the column main bars 22 at a predetermined pitch, and are fixed to each other by binding wires (not shown). The hoop lines 24 are also arranged inside the joint 10 and have the same pitch as the outside of the joint 10. Note that the pitch of the hoop lines 24 inside and outside the joint 10 may be changed.

  Similarly, rib bars (shear reinforcement bars) 34 are wound around the beam main bars 32 at a predetermined pitch, and are fixed to each other by a binding wire (not shown).

(Action / Effect)
According to the joint structure of the column beam according to the first embodiment, as shown in FIG. 1A, when the moment M acts on the beam 30 and the tensile force N acts on the beam main bar 32, the side receiving the tensile force. The supporting pressure P acts on the end face 40E of the mechanical joint 40. Therefore, the tensile force N can be resisted by the adhesion force between the outer peripheral surface of the beam main bar 32 and the concrete C and the support pressure P between the end surface 40E of the mechanical joint 40 and the concrete C. it can.

  Therefore, compared to the case where the mechanical joint 40 is not provided on the beam main bar 32 in the joint portion 10, the beam main bar 32 is less likely to slide against the concrete C. For this reason, the crack of the junction part 10 by the fall of the adhesive force of the beam main reinforcement 32 and the concrete C can be suppressed.

  The bearing area ratio R between the mechanical joint 40 and the beam main bar 32 is R ≧ 3.0. For this reason, when a tensile force is applied to the beam main bar 32, the size of the cone-shaped fracture region V where the concrete C is broken in a conical shape with the portion contacting the end surface 40E of the mechanical joint 40 as a vertex is R <3. Larger than that of 0.0. For this reason, compared with the case of R <3.0, the intensity | strength until it reaches a cone-shaped fracture is large. Therefore, the joint 10 is difficult to break.

  In addition, when there is no need to consider cone-shaped fracture, the bearing area ratio R can be set to R <3.0. If the bearing area ratio R is reduced, the mechanical joint 40 can be reduced, so that the bars are easily arranged inside the joint 10.

[Second Embodiment]
In the joint structure of the column beam according to the first embodiment, the end of the beam main bar 32 is joined by the mechanical joint 40 in the joint 10, and the column main bar 22 penetrates the joint 10 in the vertical direction. However, in the joint structure of the column beam according to the second embodiment, as shown in FIG. 2 (A), the end of the column main bar 22 is connected by a mechanical joint 42 in the joint 10, The main beam 32 penetrates the joint portion 10 in the left-right direction (substantially horizontal direction). As shown in FIG. 2B, when the beam 30 is provided only on one side of the column 20, the beam main bar 32 does not need to penetrate the joint portion 10.

  When the column main bars 22 are connected by the mechanical joints 42 in this way, for example, when a moment M acts on the columns 20 and a tensile force N acts on the column main bars 22, the end face of the mechanical joint 42 on the side receiving the tensile forces N The support pressure P acts on 42E. For this reason, the tensile force N can be resisted by the adhesion force between the outer peripheral surface of the columnar reinforcement 22 and the concrete C and the support pressure P between the end surface 42E of the mechanical joint 42 and the concrete C. it can. Therefore, even with such a configuration, it is possible to suppress cracking of the joint portion 10 due to a decrease in the adhesive force between the column main bars 22 and the concrete C.

  Furthermore, when the column main bars 22 are connected by the mechanical joints 42, the strength until reaching the cone-like fracture is increased by setting the bearing area ratio R between the mechanical joints 42 and the column main bars 22 to 3.0 or more. Thus, the breakage of the joint portion 10 can be suppressed.

[Third Embodiment]
Moreover, in the column-beam joint structure according to the first embodiment, the end of the beam main bar 32 is connected by the mechanical joint 40 in the joint 10, but the column according to the third embodiment. In the joint structure of the beam, as shown in FIG. 3, the beam main bars 32 are connected by a mechanical joint 44 embedded outside the joint 10, that is, inside the beam 30.

  Even with such a configuration, cracking of the joint portion 10 can be suppressed by the support pressure P generated between the end surface 44E of the mechanical joint 44 and the concrete C with respect to the tensile force N applied to the beam main bar 32. Further, if the mechanical joint 44 is embedded in the beam 30 so that the end surface of the mechanical joint 44 coincides with the end surface of the beam 30, the column 20 in which the joint portion 10 and the column portion 20A are integrated, and the joint portion 10 are combined. The beams 30 to be joined to each other can be formed of precast concrete. In this case, a mechanical joint 44 opened at the end face of the beam 30 is inserted into the beam main reinforcing bar 32A protruding from the side surface of the joint portion 10.

[Fourth Embodiment]
In the joint structure of the column beam according to the fourth embodiment, as shown in FIGS. 4A and 4B, the column main reinforcement 22 is formed by a mechanical joint 46 embedded in the outside of the joint portion 10, that is, in the pillar portion 20A. Connected.

  Even with such a configuration, cracking of the joint portion 10 can be suppressed by the support pressure P generated between the end surface 46E of the mechanical joint 46 and the concrete C with respect to the tensile force N applied to the columnar reinforcement 22. Further, if the mechanical joint 46 is embedded in the column portion 20A so that the end face of the mechanical joint 46 is in contact with the end face 10E of the joint portion 10, the beam 30 integrated with the joint portion 10 and the joint portion 10 are joined. Each column portion 20A can be formed of precast concrete. In this case, the mechanical joint 46 opened at the end surface of the column portion 20A is inserted into the column main reinforcing bars 22A protruding from the upper and lower surfaces of the joint portion 10, respectively.

  As described above, the column-beam joint structure according to the third and fourth embodiments includes the column 20 using the cast-in-place concrete and the joint 10 of the beam 30, the column 20 using the precast concrete, and the beam. It can also be applied to 30 joints 10. In addition, although the column 20 and the beam 30 are made of reinforced concrete, they can be made of steel reinforced concrete.

[Fifth Embodiment]
In the column beam joint structure according to the fourth embodiment, the column main reinforcement 22A embedded in the connection portion 10 and the column main reinforcement 22B embedded in the column portion 20A have the same diameter. In the column beam joint structure according to the fifth embodiment, as shown in FIG. 5, the column main reinforcement 22A has a larger diameter or higher strength than the column main reinforcement 22B. When the column main reinforcing bar 22A has a larger diameter than the column main reinforcing bar 22B, a deformed reinforcing bar of the same steel type is used, for example, up to two size differences of standard nominal diameters defined in JIS G3112.

  By doing in this way, the elongation of the column main reinforcement 22B when the tensile force N acts on the column main reinforcement 22 becomes small. For this reason, the adhesion stress which acts on concrete C is reduced, and the crack of the junction part 10 can be suppressed.

  Note that the mechanical joint 40 according to the first embodiment shown in FIGS. 1A and 1B and the mechanical joint 42 according to the second embodiment shown in FIGS. In order to apply a supporting pressure from the surface to the concrete C of the joint portion 10, it is necessary that the both end surfaces have a length that does not protrude from the joint portion 10. On the other hand, the mechanical joint 44 according to the third embodiment shown in FIG. 3 and the mechanical joint 46 according to the fourth and fifth embodiments shown in FIGS. 4 (A) and 4 (B) and FIG. Since the supporting pressure is applied to the concrete of the joint portion 10 from the outside, the length is not limited. For this reason, when the dimension of the junction 10 is small, it is preferable to use the mechanical joint 44 or the mechanical joint 46.

[Sixth Embodiment]
(Constitution)
In the column beam joint structure according to the sixth embodiment, as shown in FIG. 6A, the mechanical joint 40 (see FIG. 1A) in the column beam joint structure according to the first embodiment is replaced. A mechanical fixing device 50 is used. The mechanical fixing device 50 is embedded in the central portion of the joint 10, and the main beam 32 passes through the inside of the mechanical fixing device 50. The mechanical fixing device 50 is an example of a supporting member in the present invention.

  As shown in FIG. 6B, the mechanical fixing device 50 has a shape in which a flange 50B projects radially from the axial end of the cylindrical main body 50A, and is a threaded bar or deformed bar. The main beam 32 is penetrated. Further, the mechanical fixing tool 50 and the beam main bar 32 are fixed by a grout material injected into a gap between the beam main bar 32 and the main body 50A. The area of the bearing portion of the flange 50B of the mechanical fixing tool 50 is set to be three times or more the cross-sectional area of the beam main bar 32 as in the area of the bearing portion of the mechanical joint 40 in the first embodiment. It is arranged at the approximate center of the joint 10 of the beam main bar 32.

  The other configuration is the same as the column beam joint structure according to the first embodiment shown in FIG. In the present embodiment, the mechanical fixing device 50 has a shape including the flange 50B, but the embodiment of the present invention is not limited thereto. For example, a cylindrical mechanical fixing device without the flange 50B may be used.

(Action / Effect)
According to the joint structure of column beams according to the sixth embodiment, as shown in FIG. 6A, when a moment M acts on the beam 30 and a tensile force N acts on the beam main bar 32, a mechanical fixing device 50 is provided. Receives the tensile force, and the concrete C of the joint 10 is pressed by the mechanical fixing device 50 from the direction indicated by the arrow C1. Moreover, the concrete C is pressed from the direction opposite to the side receiving the tensile force N from the direction indicated by the arrow C2. As a result, the compression struts indicated by hatching from the corner of the joint 10 toward the opposite corner and from the bearing-bearing surface at the center of the joint 10 toward the corner of the joint 10 respectively. S1 and S2 occur, and the yield strength of the joint 10 is improved.

  On the other hand, for example, when the mechanical fixing tool 50 is not fixed to the beam main bar 32, the compression straddle S2 does not occur from the central portion of the joint portion 10. For this reason, comparing the joint structure of the column beam according to the present embodiment in which the mechanical fixing tool 50 is fixed to the beam main bar 32 and the structure in which the mechanical fixing tool 50 is not fixed to the beam main bar 32, The joint structure of the column beam according to the present embodiment has higher proof strength of the joint 10.

  Further, the tensile force N can be resisted by the adhesion force between the outer peripheral surface of the beam main bar 32 and the concrete C and the support pressure between the mechanical fixing device 50 and the concrete C. Therefore, the crack of the junction part 10 by the fall of the adhesive force of the beam main reinforcement 32 and the concrete C can be suppressed.

  Furthermore, the bearing area ratio between the mechanical fixing device 50 and the beam main bar 32 is set to be three times or more. Therefore, the cone-like destruction of the concrete C hardly occurs. In addition, when it is not necessary to consider cone-shaped fracture, the bearing area ratio can be set to less than 3. If the bearing area ratio is reduced, the mechanical fixing device 50 can be reduced, so that the bars are easily arranged inside the joint 10.

[Seventh Embodiment]
In the column beam joint structure according to the sixth embodiment, the column main bars 22 are arranged linearly inside the joint 10. In the column beam joint structure according to the seventh embodiment, As shown in FIG. 7, the column main reinforcing bars 22 </ b> C near one side surface of the column 20 and the column main reinforcing bars 22 </ b> D near the other side surface intersect with each other in an X shape inside the joint 10.

  With such a configuration, for example, when the tensile force N is applied to the beam main bar 32, the diagonal crack CR that is to be generated along the diagonal K at the corner of the joint 10 is formed at the center of the joint 10. The column main bars 22 intersect with the direction. For this reason, generation | occurrence | production of the diagonal crack CR can be suppressed.

[Eighth Embodiment]
In the beam-column joint structure according to the sixth and seventh embodiments, the mechanical fixing device 50 is fixed to the beam main bar 32. However, in the beam-column joint structure according to the eighth embodiment, as shown in FIG. As shown in FIG. 8A, the mechanical fixing tool 50 is not fixed to the beam main bar 32 but the mechanical fixing tool 50 is fixed to the column main bar 22. The mechanical fixing device 50 may be fixed to both the beam main bar 32 and the column main bar 22.

  When the mechanical fixing device 52 is fixed to the column main reinforcement 22, the concrete C of the joint portion 10 is connected to the mechanical fixing device 50 by the tensile force N applied to the column main reinforcement 22 by the moment M acting on the column 20. It is pressed from the direction shown by the arrow C1 by the support pressure generated at. Further, a compressive force acts on a portion opposite to the side receiving the tensile force N and is pressed from the direction indicated by the arrow C2. Thereby, compression struts S1 and S2 indicated by shading are generated from the corner of the joint 10 toward the opposite corner and from the corner of the joint 10 toward the center of the joint 10, respectively. And the proof stress of the junction part 10 improves.

  Further, when the mechanical fixing device 50 is fixed to the column main reinforcement 22, the beam main reinforcement 32 is replaced with the hoop reinforcement 24 wound around the column main reinforcement 22 inside the joint portion 10 as shown in FIG. A loose stirrup 34 can be arranged. By arranging the streaks 34 inside the joint 10 in this way, it is possible to prevent the beam main bars 32 from being deformed as indicated by the broken line H.

  8A and 8B, the beam main bars 32 are linearly arranged inside the joint portion 10, but the embodiment of the present invention is not limited to this. For example, similarly to the column main bars 22A and 22B of the column beam joint structure according to the seventh embodiment shown in FIG. 7, the beam main bar (upper bar) 32 near the upper surface of the beam 30 and the beam main bar (lower bar) near the lower surface. ) 32 may be crossed in an X shape inside the joint 10.

  Further, the structure in which the column main bars 22 or the beam main bars 32 intersect in the X shape inside the joint portion 10 as described above is the joint structure and diagram of the column beam according to the first embodiment shown in FIG. 2 (A), (B), FIG. 3, FIG. 4 (A), (B) can be applied to various embodiments, that is, configurations using mechanical joints 40, 42, 44, 46. .

  Even if the configuration in which the column main bars 22 or the beam main bars 32 intersect in the X shape inside the joint portion 10 is applied to these embodiments, the occurrence of the oblique crack CR can be suppressed. As described above, the configurations shown in the embodiments of the present invention can be used in appropriate combination.

10 joint 20 pillar (steel reinforced concrete pillar)
20A Column 22 Column main bar 22A Column main bar (column main bar of joint)
22B Column main bar (column main bar of column part)
20 beams (steel reinforced concrete beams)
32 Beam main bar 34 Stirrup (shear reinforcement)
40, 42, 44, 46 Mechanical coupling (supporting member)
50 Mechanical fixing device (supporting member)

Claims (6)

A joint in which the column reinforcement of a reinforced concrete column and the beam reinforcement of a reinforced concrete beam are arranged;
A supporting member that is provided in the column main bar or the beam main bar and generates a supporting pressure;
Column beam joint structure with   2. The beam-column joint structure according to claim 1, wherein the bearing member is a mechanical joint provided at the joint or outside the joint. 3.   2. The column beam joint structure according to claim 1, wherein the bearing member is a mechanical fixing tool, and a bearing generating surface is located at a central portion of the joint of the beam main bar.   When the supporting member is provided on the column main bar, the beam main bar intersects in an X shape, and when the supporting member is provided on the beam main bar, the column main bar crosses in an X shape. The joint structure of a column beam according to any one of claims 1 to 3.   The joint structure of a column beam according to any one of claims 1 to 3, wherein the supporting member is provided on the column main bar, and a shear reinforcement bar is wound around the beam main bar.   A column beam joint structure comprising a joint in which a column reinforcement of a reinforced concrete column and a beam reinforcement of a reinforced concrete beam are arranged, and the column reinforcement of the joint is larger in diameter than the column reinforcement of the column .

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