JPH108551A - Structure of beam-column joint - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve strength at a beam-column joint part by a method wherein strength and tenacity of concrete placed to the beamcolumn joint part are heightened while bond strength for sticking to reinforcing bars is increased. SOLUTION: A beam-column joint structure 10 is for a beam-column joint part 3 of a reinforced concrete structure, for which fiber reinforcement members 4 are mixed with concrete C to be placed at the joint part 3. Synthetic resin fibers made of Vinylon or the like can be used, besides such materials as carbon fiber or steel wool, as the fiber reinforcement members 4. With such beam- column joint structure 10, strength and tenacity can be increased for the concrete C by the fiber reintorcement members 4, and bond strength of the concrete C for sticking to column main reinforcements and beam main reinforcements to be arranged at the beam-column joint part 3 can be heightened, and thereby strength for the beam-column joint part 3 can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a beam-column connection structure in which a column member and a beam member are joined in a reinforced concrete structure or the like.

[0002]

2. Description of the Related Art In a reinforced concrete structure, a beam-column connection portion at which a column member and a beam member are joined is generally provided at a portion where the column member and the beam member are joined, with columns arranged at the members. It is constructed by connecting the main reinforcing bars and beam reinforcing bars to each other, arranging shear reinforcing bars for reinforcing this portion, and then pouring concrete so as to bury these main reinforcing bars and reinforcing bars.

[0003]

However, in general, when the strength of a column member or a beam member to be joined thereto is increased in the column-beam connection portion, the strength of the connection portion is relatively large with respect to the column or the beam member. Tends to be low. In addition, if the amount of shear reinforcing bars arranged here is increased in order to improve the strength of the beam-column connection, the main columns, beam main bars, shear reinforcing bars, etc. will be complicatedly mixed at this connection. However, there is a problem in that the amount of concrete poured into the connection tends to be smaller than in other parts.

On the other hand, an axial force from each member acts on the beam-to-column connection, and a bending stress acts when each member is relatively displaced by an earthquake. for that reason,
Stress such as excessive shear force acts on the concrete portion of the beam-column connection, and it is necessary to improve the strength and toughness of this portion.

[0005] The present invention has been made in view of the above-described problems, and by increasing the strength and toughness of concrete cast in a beam-column joint, and by increasing the bonding strength with a reinforcing bar, An object of the present invention is to provide a beam-column connection structure capable of improving the strength of the beam-column connection.

[0006]

SUMMARY OF THE INVENTION A column-beam connection structure according to the present invention has been made to achieve the above object.
The gist of the invention is characterized in that a fiber reinforcing material is mixed into concrete cast at the joint in a beam-column joint of a reinforced concrete structure or the like (claim 1). According to such a beam-to-column connection structure, the fiber reinforcement is mixed into the concrete cast here, so that the fiber reinforcement increases the strength and toughness of the concrete, and the beam-to-column connection is Since the strength of adhesion between the column main bars or beam main bars to be arranged and the concrete is increased, the strength of the column-beam joint can be improved.

In the above-mentioned beam-column connection structure, it is preferable that the fiber reinforcing material is carbon fiber. According to such a beam-to-column connection structure, since carbon fiber is unlikely to rust, it is possible to prevent the concrete portion from deteriorating with time, and to improve the reliability of the beam-to-column connection. it can.

Further, in the above-mentioned beam-column connection structure,
The fiber reinforcement may be a synthetic resin fiber (claim 3). According to such a beam-to-column connection structure, the synthetic resin fiber does not rust and is lightweight, so that it is possible to prevent deterioration of the concrete portion and to increase the strength per unit weight of the concrete. Can be increased.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below in detail with reference to the drawings. FIG. 1 shows a beam-column connection structure 10 according to the present embodiment. In the present embodiment, the joint 3 is a portion where the four beam members 2 are joined to the reinforced concrete column 1 having a rectangular cross section. In the joint 3, the column main bar 1 a of the column member 1 is provided.
The beam reinforcing bars 2a of the beam members 2 are connected to each other, and the shear reinforcing bars 4 are arranged so as to collectively surround the outer periphery of the column main bar 1a.

The connection part 3 is constructed, for example, by laying a formwork for constructing the beam member 2 above the constructed column member 1. That is, as shown in the figure, the beam formwork 21 is erected at the upper part of the column member 1 constructed by laying a precast member or cast-in-place of concrete, and arranging the beam main reinforcement 2a in each beam formwork 21. At the same time, while connecting the beam main reinforcements 2a to each other in the connection part 3, the shear reinforcement 4 is arranged in the connection part 3, and then the connection part formwork is formed so as to surround the connection part 3. 31 so that the main bars and the shear reinforcing bars are buried.
Concrete is poured into the beam formwork 1 and the beam formwork 21.

Here, a fiber reinforcement 5 is mixed in the concrete cast into the connection portion 3. The fiber reinforcing material 5 improves the strength and toughness of the concrete. For example, in addition to short fibers such as steel fibers and steel fibers usually used for fiber reinforced concrete, synthetic resin fibers such as polyethylene and vinylon , Carbon fiber, glass fiber and the like can be used.

As the steel fiber used as the fiber reinforcing material 5, short fibers mixed with ordinary fiber reinforced concrete can be used.
It is preferable to use one having a length of about 6 mm and a length of about 20 to 40 mm. And as the short fiber, as well-known, for example, rolled, cut wire or steel wire cut to a predetermined length with a cutter, a shear fiber manufactured by shearing a thin steel sheet,
There is a cutting fiber obtained by cutting a steel thick plate with a rotating slice flat blade, and preferably, the shape is modified, or a streak is formed on the surface to improve adhesion to concrete. Aim.

On the other hand, when the carbon fiber is used as the fiber reinforcing material 5, the carbon fiber hardly rusts, so that the concrete portion can be prevented from deteriorating with time. When synthetic resin fibers are used, since the synthetic resin fibers are lightweight, the strength per unit weight of concrete can be increased.

The kneading of the fiber reinforcing material 5 is as follows:
When putting the fiber reinforcement 5 into the concrete mixer,
The mixture is uniformly dispersed in concrete using a disperser, and kneaded while preventing the formation of fiber balls. Thereafter, the concrete C into which the fiber reinforcing material 5 is mixed is poured into the connection part 3 by a pressure pump or the like. Next, when the concrete C has hardened, the beam formwork 21 and the joint formwork 31 are formed.
And finish the construction work of the beam-column connection structure. When a precast formwork is used as the formwork, it is not necessary to remove the formwork because the formwork is left on the surface of the member.

According to the beam-column connection structure 10 constructed in this way, the concrete portion is cast by the stress transmitting action of the fiber reinforcing material 5 mixed in the concrete C cast into the connection portion 3. The deformability and resistance to cracks are increased, and the adhesion strength between the column main reinforcement 1a and the beam main reinforcement 2a arranged in the joint 3 and the concrete C can be increased. As a result, the strength of the joint 3 And toughness can be increased.

[0016]

As described above in detail, according to the beam-column connection structure of the present invention, the fiber reinforcing material is mixed with the concrete cast in the connection portion, whereby the concrete is strengthened by the fiber reinforcing material. In addition to the increase in strength and toughness of the joints, the strength of the connection between the column main bars and the beam main bars arranged in the beam-column joints and the concrete is increased, so that the strength of the beam-column joints can be improved.

Further, in the above-mentioned beam-column connection structure, if carbon fiber is used as the fiber reinforcing material, the carbon fiber hardly rusts, so that the concrete portion can be prevented from deteriorating with time. The reliability of the beam connection can be improved.

Further, in the above-mentioned beam-column connection structure,
By using a synthetic resin fiber as the fiber reinforcing material, the synthetic resin fiber does not rust and is lightweight, so that it is possible to prevent deterioration of the concrete portion and to reduce the weight per unit weight of the concrete. Strength can be increased.

[Brief description of the drawings]

FIG. 1 is a horizontal sectional view showing a beam-column connection structure according to an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Column member 2 Beam member 3 Connection part 4 Shear reinforcement 5 Fiber reinforcement 10 Column beam connection structure C Concrete

Continued on the front page (72) Inventor Shinji Takami 4-640 Shimoseito, Kiyose-shi, Tokyo Inside Obayashi Corporation Technical Research Institute

Claims (3)

[Claims] 1. A reinforcing structure for a beam-column joint of a concrete structure, wherein a fiber reinforcing material is mixed into concrete cast in the port. 2. The beam-column connection structure according to claim 1, wherein the fiber reinforcing material is carbon fiber. 3. The beam-column connection structure according to claim 1, wherein the fiber reinforcement is a synthetic resin fiber.