JPH11350593A - Seismic control frame by unbonding - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a seismic control frame by unbonding reinforcing steel or steel material, which prevents a large number of cracks from occurring in RC beams and walls even when a large bending moment acts during an earthquake. SOLUTION: At a joint between a beam and a column by RC construction, an unbonded portion not fixed to concrete is formed in a main reinforcement of the beam, and a slit portion not fixed to the column is formed at an end of the beam. Further, at the joint between the wall and the foundation by the RC structure, an unbonded portion that does not adhere to concrete is formed in a vertical streak at an end of the wall, and a slit portion that does not adhere to the foundation is formed at the lower end of the wall. The unbond portion or the slit portion is formed by applying a viscoelastic body. A shear reinforcement is provided at the joint to reinforce the joint.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration control frame by unbonding (non-fixing) reinforcing steel or steel.

[0002]

2. Description of the Related Art A conventional RC (reinforced concrete) beam is generally integrated with a pillar or a wall at the end, and the wall is also integrated with a foundation. However, when a large bending moment acts on the beam during an earthquake, many cracks are generated in the concrete part, and when a large bending moment acts on the legs of the multi-story wall, the reinforcing steel on the tension side is elongated and adheres to the reinforcing steel Many cracks occur in the concrete part.

[0003]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional circumstances, and has been made to prevent a large number of cracks from being generated in RC beams and walls even when a large bending moment acts during an earthquake. The purpose is to provide a seismic control frame by unbonding reinforcing bars.

[0004]

As a means for achieving this object, the present invention provides an unbonded portion which is not fixed to concrete at a main reinforcing bar of a beam at a joint between a beam and a column made of RC. The gist of the present invention is to provide an unbonded seismic control frame in which a slit portion not fixed to the column is formed at the beam end. Further, at the joint between the wall and the foundation by the RC structure, an unbonded portion not fixed to the concrete was formed in the vertical streak at the end of the wall, and a slit portion not fixed to the base was formed at the lower end of the wall. The gist is the seismic control frame by unbonding. Further, in the vibration control frame by unbonding, the unbonded portion or the slit portion is formed by applying a viscoelastic body or a viscous body, and a shear reinforcing bar is arranged at the joint portion. Things.

[0005]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 shows an example in which the present invention is applied to an RC beam. Reference numeral 1 denotes a beam formed between columns 2, and a main bar 3 penetrates the beam 1 and has both ends 3.
a is incorporated in the pillars 2 on both sides, and the main reinforcement 3 in the beam 1
The accessory bars 4 are arranged at regular intervals along.

At both ends of the beam 1, that is, at the joint with the column 2, unbonded portions 6 are formed around the both ends of the main bar 3 without being fixed to the cast concrete 5, and the upper and lower ends of the beam 1 are formed. The small slit portions 7 are formed between the pillars 2 without fixing.

[0007] The unfixed unbonded portion 6 is, for example,
Can be formed by applying a material such as a viscoelastic body to the surroundings and then pouring concrete 5. The viscoelastic body functions to prevent the main bar 3 from deteriorating, and also prevents buckling of the main bar 3 at the time of compressive stress. It is preferable to apply the coating material with a small thickness since a large gap is not generated. The slit 7
The viscoelastic body or the like may be applied to the portion of the column 2 corresponding to the slit 7 before the concrete 5 is cast.

When the non-fixed slit portion 7 is formed, the beam 1
Since the resistance to the shearing force acting on the beam may be weakened, the shear reinforcing bars 8 intersect the joint between the beam 1 and the column 2 substantially in an X-shape, and a straight shear reinforcing bar 8 is also provided at the intersection. It is preferable to arrange and reinforce each.

According to such an unbonded structure of the beam 1, the tensile strain due to the bending deformation of the concrete 5 is concentrated on the slit portion 7 at the time of the earthquake, so that the crack of the beam 1 is reduced in other portions. In addition, the unbonded portion 6 has an operation of relaxing or absorbing the tensile stress by extending the main bar 3 at the time of bending deformation. Since the compressive stress is usually borne by the concrete 5 and the shear stress is borne by the shear reinforcement 8, there is no problem such as breakage. FIG. 2 is a conceptual diagram illustrating a deformed state of the beam 1.

FIGS. 3 (a) and 3 (b) show an example in which the present invention is applied to an RC wall. Reference numeral 11 denotes a wall, and a vertical streak 12 penetrates the wall 11, and a lower end 12a is formed. The horizontal streak 14 is incorporated in the base portion 13 and is arranged in parallel with the vertical streak 12 at a certain interval in a direction perpendicular to the vertical streak 12.

At the joints between the legs of the wall 11, that is, the base portion 13, unbonded portions 16 are formed around the both ends of the vertical bars 12 without being fixed to the cast concrete 15, and the lower end of the wall 11 is formed. A slight slit portion 17 is formed between the base portion 13 and the left and right portions without fixing.

The unfixed unbonded portion 16 can be formed by applying a material such as a viscoelastic material around the vertical streaks 12 and then pouring concrete 15 in the same manner as described above. The viscoelastic body functions to prevent the deterioration of the vertical streaks 12, and also prevents the vertical streaks 12 from buckling at the time of compressive stress. It is preferable that the coating be thin so that a large gap does not occur. The slit portion 17 may be formed by applying a viscoelastic material or the like to the portion of the base portion 13 corresponding to the slit portion 17 before the concrete 15 is cast.

If the non-fixed slit portion 17 is formed, the resistance to the axial force and the shearing force acting on the base portion 13 may be weakened. Therefore, as shown in FIG. A plurality of shear reinforcing bars 18 are provided near the center of the joint.
Are preferably crossed substantially in an X-shape, and a plurality of linear shear reinforcing bars 18 are also provided at the crossings to reinforce each other.

According to the unbonded structure of the wall 11, since the tensile strain due to the bending deformation of the concrete 15 is concentrated on the slit portion 17 at the time of an earthquake, cracks on the wall surface are reduced in other portions. The unbonded part 1
Numeral 6 acts to relax or absorb the tensile stress by the extension of the longitudinal streaks 12 during bending deformation. Conventionally, when a large bending moment acts on the legs of the multi-story wall, the reinforcing steel on the tension side is elongated and many cracks are generated in the concrete portion adhering to the reinforcing steel. Such cracks can be prevented. Since the compressive stress is usually borne by the concrete 15 and the shear stress is borne by the shear reinforcement 18, there is no problem such as breakage. FIG. 5 is a conceptual diagram illustrating a deformed state of the wall 11.

[0015]

As described above, according to the present invention,
RC beams and walls are formed with unbonded reinforcing bars at the joints to other members, and non-fixed slits are formed at the ends. It does not have many cracks and exerts the effect of damping to minimize damage. In addition, by applying a viscoelastic body to the unbonded portion, it is possible to prevent deterioration of the reinforcing bar, and it is also possible to reinforce by providing a shear reinforcing bar at the joint.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing an example in which the present invention is applied to an RC beam.

FIG. 2 is a conceptual diagram showing a deformed state of a beam during an earthquake.

FIG. 3 shows an example in which the present invention is applied to an RC wall, (a) is a schematic sectional view, and (b) is a sectional view taken along line AA.

FIG. 4 is an explanatory view showing an arrangement state of shear reinforcing bars.

FIG. 5 is a conceptual diagram showing a deformed state of a wall during an earthquake.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Beam 2 ... Column 3 ... Main reinforcement 4 ... Secondary reinforcement 5 ... Concrete 6 ... Unbonded part 7 ... Slit part 8 ... Shear reinforcement 11 ... Wall 12 ... Vertical reinforcement 13 ... Foundation part 14 ... Horizontal reinforcement 15 ... Concrete 16 ... Unbonded part 17 ... Slit part 18 ... Shear reinforcement

Claims (4)

[Claims] At a joint between a beam and a column by RC construction,
An unbonded seismic control frame in which an unbonded portion not fixed to concrete is formed in the main reinforcement of the beam, and a slit portion not fixed to the column is formed at the end of the beam. 2. An unbonded portion not fixed to concrete is formed at a vertical streak at an end of the wall at a joint between a wall and a base portion by RC construction, and a slit portion not fixed to the base portion at a lower end portion of the wall. The seismic control frame by unbonding that formed the. 3. The unbonded portion or the slit portion is formed by applying a viscoelastic body or a viscous body.
Seismic control frame by unbonding as described. 4. The vibration control frame by unbonding according to claim 1, wherein a shear reinforcing bar is provided at the joint.