JPH01226943A - Slip prevention of beam main-reinforcement at joint section of column and beam in reinforced concrete structure - Google Patents

Abstract

PURPOSE:To fit a one-piece main-reinforcement firmly on concrete by penetrating a column main-reinforcement through the penetrated slot at the connecting section of a column and a beam which are PC-formed, and by injecting grout into the slot. CONSTITUTION:The section of the one-piece main-reinforcement 3 of a beam is solidified with high-strength concrete, and is integrally combined as a PC member 4. With the PC member 4, a penetrated slot 6 for the column main- reinforcement 5 of a column 1 to pass through is also formed, and on the side surface 7, a rugged section is roughly formed. The PC member 4 is suspended by a crane or the like, and the column main-reinforcement 5 is penetrated through the penetrated slot 6, and after that, grout is injected into the penetrated slot 6, and the column main-reinforcement 5 and the PC member 4 are integrally formed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a method for preventing slip of beam main reinforcements at column-beam joints in reinforced concrete structures.

(Prior Art) In reinforced concrete frame structures, the main beam reinforcement in the joint between the center column and the beam is generally provided through-through. Then, concrete was poured at the intersection of the main reinforcement of the beam and the main reinforcement of the column, completing the connection of the column and beam.

However, there are cases where the anchorage length of the main beam reinforcement is not secured sufficiently, and
In cases where there is a slight deficiency in the plastic deformation capacity of adjacent beam members, the removal of the beam main reinforcement (the main reinforcement of the beam) from the joint becomes a seismic problem.

Therefore, methods such as arranging stirrups at the column-beam joints have been proposed, such as Japanese Patent Publication No. 58-42340.

(Problem to be solved by the invention) However, the method of increasing the number of hoop reinforcements or the method of using fixing plates requires the insertion of additional reinforcing bars or metal fittings into the joint where the main reinforcement of the column or the main reinforcement of the beam is complicated. As a result, it becomes a hindrance to concrete pouring and filling, creating voids within the joint, and as a result, the reinforcing bars do not perform adequately in accordance with the amount of reinforcing bars used, resulting in poor economic efficiency.

The above-mentioned voids are particularly noticeable when concrete with a high compressive strength is poured into the column-beam joint and the water-cement ratio is hardened.

The present invention was made in view of the above circumstances, and its purpose is that when a strong earthquake force acts on a reinforced concrete rigid frame structure, a large shearing force acts on the column-beam joint, and this repeated applied force is applied to the beam main reinforcement. To provide a method for preventing slip at a column-beam joint, which solves the problem of increasing the pull-out of the main reinforcement of the beam due to the deterioration of the adhesion force with concrete at the joint.

(Means for Solving the Problems) In order to achieve the above object, the method for preventing slip of the main beam reinforcement at the column-beam joint of a reinforced concrete structure according to the present invention provides a method for preventing slip of the main beam reinforcement at the column-beam joint. For the main reinforcement section of the beam, a through hole is provided for the main column reinforcement to form a precast concrete column/beam joint made of high-strength concrete, and then the column main reinforcement is inserted into the through hole of the precast concrete column/beam joint. After insertion, grout is injected into the through hole to integrate the column main reinforcement and the precast concrete column/beam joint where the main reinforcement section of the beam is solidified.

(Function) The main beam reinforcement at the column-beam joint is precast with high-strength concrete in advance to ensure that the main reinforcement and concrete are firmly anchored.

This increases the shear rigidity in combination with the strong adhesion of high-strength concrete, and prevents deterioration of the adhesion performance of the main reinforcement.

Furthermore, the precast joint is integrated with the column by passing the column main reinforcement through the through hole. Therefore, sufficient anchorage can be easily obtained without the need for filling the entire joint with concrete, and the energy absorption capacity of the beam end plastic hinge part is sufficient, so the precast joint can be used in conjunction with the vertical load of the column. Toughness is increasing.

(Embodiments) Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

The figure shows the joints between the beams and the columns, where they intersect in the inter-beam and girder directions. The main reinforcing bars 3 of the beams that pass linearly through the column-beam joint 2, where the top of the column 1 and the intersection of the cross-shaped beams are integrated, are an integral extension of the main beam reinforcing bars arranged in parallel. The portion where the main through-bars 3-3 intersect is precast (hereinafter abbreviated as PC).

The concrete used for the PC member 4 is high-strength concrete in order to firmly maintain the intersection angle of the through main reinforcements 3-3 and the anchoring strength of the reinforcing bars.

High-strength concrete can be obtained by hardening ordinary cement with a low water-to-cement ratio; however, if the compressive strength is to be extremely high, a water reducer may be mixed in, or carbon fibers with high tensile strength may be mixed with ordinary cement. A mixture of short fibers such as aramid fibers and polyethylene fibers may also be used.

That is, the 3 portions of the main reinforcing bars of the beam are solidified with high-strength concrete and are integrally combined as the PC member 4. This PC member 4 is further provided with a through hole 6 through which the column main reinforcement 5 of the column 1 passes in a vertical direction orthogonal to the through main reinforcement 3, and the side surface 7 is roughened.

The main column reinforcement 5 inserted into the through-hole 6 of the PC member 4 is a cast-in-place column 1 up to the middle of supporting the column-beam joint 2, and is a portion extending above the top.

After lifting the PC member 4 using a lifting machine (not shown) or the like and passing the column main reinforcement 5 through the through hole 6, grout is injected into the through hole 6 to connect the column main reinforcement 5 and the PC member 4. By integrating the columns and beams, the connection between the columns and beams is completed. Bulking agents may be mixed into the grout. Stirrups are arranged on the main beam reinforcement bars extending in all directions from the sides of the PC member 4, and concrete is poured on-site together with the slab to complete the beam.

(Effects) Since the present invention constructs a column-beam joint of a reinforced concrete structure as described above, the following effects are achieved.

The main reinforcement of the beam is made of high-strength concrete, so even if it is hard-mixed, the concrete is placed in a sufficiently dense manner, and the adhesion between the main reinforcement and the concrete is tight and strong. Retention is obtained. Therefore, the energy absorption capacity of the beam end plastic hinge portion is maintained sufficiently, and the phenomenon in which the beam main reinforcement is pulled out from the joint portion is prevented. Therefore, the restoring force characteristics of the entire building frame are less likely to deteriorate, resulting in excellent earthquake resistance.

In addition, there is no need to use hoop reinforcements or stirrups for the through-reinforcement parts when converting to PC, and the cross section of the joint does not have to be made large, resulting in less increase in dead weight and loss of space, and moreover, it is possible to fill the concrete densely. Easy and economically efficient.

In addition, since the main column reinforcement is simply passed through the through hole of the PC column-beam joint and grout is injected into this hole, the construction time for this joint is shorter than when concrete is poured on-site at the column-beam joint. This will significantly shorten the construction period for the entire structure.

[Brief explanation of the drawing]

FIG. 1 is a perspective view for explaining the method of the present invention. 1...Column 2...Column・
Beam joint 3...Through main bar 4...
...PC member 5...Column main reinforcement 6...
...Through hole 7...Side

Claims (1)

[Claims] (1) At the column-beam joint, for the main reinforcement of the beam that is perpendicular to the main reinforcement of the column, through-holes are provided for the main reinforcement of the column, and precast concrete columns made of high-strength concrete are installed.
A beam joint was constructed, and then the column main reinforcement was inserted into the through hole of the precast concrete column/beam joint, and then grout was injected into the through hole to solidify the column main reinforcement and the through main reinforcement part of the beam. A method for preventing slip of beam main reinforcement at a column/beam joint of a reinforced concrete structure, characterized by integrating the precast concrete column/beam joint.