JPS61191742A - Pillar and beam connection part in reinforced concrete ramenstructure - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a column-beam joint in a reinforced concrete rigid frame structure.

(Prior Art) Normally, at the joint between a center column and a beam in a reinforced concrete rigid frame structure, the main reinforcement of the beam and column is a through reinforcement.

In addition, the normal design is designed to be a ride-yield type mechanism, and stirrup reinforcement is arranged at the plastic hinge part of the beam end.
This prevents a decrease in shear rigidity due to cracks.

(Problem to be Solved by the Invention) When a strong seismic force acts on the rigid frame structure, a large shearing force acts on the column-beam joint, causing shear cracks in the joint and reducing shear rigidity. At the same time, repeated loads act on the beam and column main reinforcements, and the adhesion strength between the main reinforcements and the joint concrete deteriorates, and the amount of main reinforcements pulled out from the joints gradually increases.

On the other hand, as mentioned above, the normal design is a beam yielding type mechanism, but in this case, bending and shear cracks occur at the plastic hinges at the ends of the beams due to repeated loads during earthquakes. penetrates from the ground, causing a decrease in shear stiffness. It is difficult to prevent the decrease in shear rigidity due to this through cracking by using conventional stirrups alone.

In recent years, the above-mentioned phenomenon has tended to become more prominent as buildings become taller and higher-strength, larger-diameter main reinforcements are arranged at higher density.

In other words, the shear stress at the column-beam joints is extremely high, forcing them into severe conditions, and the use of large-diameter, high-strength main reinforcements makes it even more difficult for the main reinforcements to adhere to the concrete at the joints. In addition, the stress level at the beam end plastic hinge is a little more severe.

This condition reduces the energy absorption capacity of the beam end plastic hinge section, and l! ! The seismic safety of the rigid frame structure, which is designed to ensure earthquake resistance, is reduced due to its ability to deform.

(Means for Solving the Problems) The present invention has been proposed to solve the above problems, and in the column-beam joints in reinforced concrete structures, mesh metal fittings buried inside the columns and beams It is characterized by being cast in high-strength concrete or steel fiber reinforced concrete within a limited column-beam joint space, and by arranging splint reinforcements in close contact with the beam main reinforcements passing through the joint space. This relates to column-beam joints in reinforced concrete rigid frame structures.

(Function) In the present invention, as described above, the column-beam joint space limited by the mesh metal fittings buried inside the column and beam is made of high-strength concrete and steel fiber-reinforced concrete. , the shear strength of the column-beam joint is increased, which not only prevents a decrease in shear rigidity due to earthquake loads in the same part, but also increases the bearing strength of the main reinforcing bars of columns and beams that pass through the joint space. This reduces the deterioration of the bond strength due to repeated loads during earthquakes, and prevents the main reinforcement from being pulled out from the column-beam joint.

In addition, since the splint reinforcement bars are arranged in close contact with the main beam reinforcements in the column-beam joint space, the bonding strength of the beam main reinforcements in the column-beam joint space is significantly increased, and the repeated loads during earthquakes are This prevents the deterioration of bond strength caused by this, and significantly reduces the amount of the main beam reinforcement from the joint.

(Effects of the Invention) As described above, according to the present invention, by increasing the shear strength of the column-beam joint, a decrease in internal shear rigidity is prevented, and the bearing strength of the main reinforcement passing through the joint, especially the beam main reinforcement, is increased. By increasing this, it is possible to prevent the main reinforcement from being pulled out and improve the earthquake resistance of reinforced concrete rigid frame structures.

In addition, the column-beam joint space is limited by concrete connecting the column and the joint and by mesh hardware buried in the column-beam joint, so high-strength concrete cast in the joint space or The steel fiber-reinforced concrete and the ordinary concrete of the columns and beams in contact with the space are integrated through pour joints and the mesh metal fittings.

(Example) The present invention will be described below with reference to the illustrated embodiments.

FIG. 1 and FIG. 2 respectively show a first embodiment of a column-beam joint of a reinforced concrete frame structure according to the present invention.
) is a column, (B) is a beam, and the main reinforcement of the column (1) and the main reinforcement of the beam (2)
Both are continuous reinforcing bars that penetrate through the column-beam joints.

There are upper and lower concrete joints in the part of the column (4) that touches the column-beam joint space, and there are left and right mesh metal fittings in the boundary between the beam end plastic hinge part and the center part of the frame in the beam (B). (4) is buried, and high-strength concrete IJ-t or steel fiber reinforced concrete (α) is installed in the above-mentioned upper and lower pour joints, the column-beam joint space limited by the net-like hardware (4), and the beam end plastic hinge part. Ordinary concrete (A) is poured into the remaining column parts and the inner center part of the beam.

The main beam reinforcement (2) is closely connected with gate-shaped or groove-shaped support reinforcement (5) in the column-beam joint space, and X-shaped reinforcing reinforcement (6) is arranged in the beam end plastic hinge area. ) are placed in close contact with each other.

In the figure, (7) is the rib of the column (4), and (8) is the stirrup of the beam (B).

In the illustrated embodiment, as described above, the column-beam joint and the beam-end greasy hinge part are made of high-strength concrete or steel fiber concrete (α), so the shear strength of each part increases. , the decline in shear rigidity due to earthquake loads is prevented, the bond strength of the column main reinforcement (1) and beam main reinforcement (2) that pass through the column-beam joint increases, and the deterioration of the bond strength due to repeated loads during earthquakes is prevented. This reduces the pull-out of the main reinforcement from the joint. Furthermore, the plastic rotation capacity at the beam end heavy hinge portion is increased.

Furthermore, since the support reinforcements (5) are closely arranged along the beam main reinforcement (2) within the column-beam joint, the bonding strength of the beam main reinforcement (2) within the column-beam joint increases significantly, and this increases the resistance during earthquakes. This prevents the deterioration of the bond strength due to repeated loading of the beam main reinforcement (2
) from the column-beam joint is significantly reduced.

Furthermore, the X-shaped reinforcing bars (6) placed in close contact with the main beam bars (2) at the end of the nine-beam hinge are designed to withstand the shear force caused by repeated external forces during earthquakes. It acts as a connecting member or stock (5trut: strut) to prevent shearing deformation of the beam end plastic hinge portion and preventing a decrease in shear rigidity.

In this way, according to the above-mentioned embodiment, by increasing the shear strength of the column-beam joint and the beam end plastic hinge part, a decrease in shear rigidity of each part is prevented, and the main reinforcement passing through the column-beam joint, especially the beam The increase in the bond strength of the main reinforcement (2) prevents it from pulling out, and the increase in the plastic rotation capacity of the beam end plastic hinge portion significantly increases the energy absorption performance of the same portion, improving the seismic performance of the reinforced concrete frame structure. It will be improved.

3 and 4 show a second embodiment of the present invention, in which high-strength concrete or steel fiber reinforced concrete (α) is poured only in the column-beam joint space.

In the figure, parts equivalent to those of the above embodiment are given the same reference numerals.

5 and 6 show a third embodiment of the present invention, in which the X-shaped reinforcing bar (6) in the first embodiment is omitted.

In the drawings, parts equivalent to those of the above embodiments are given the same reference numerals.

FIGS. 7 and 8 show a fourth embodiment of the present invention, and in the third embodiment, high-strength concrete or steel fiber reinforced concrete (α) is poured only in the column-beam joint space.

In the drawings, parts equivalent to those of the above embodiments are given the same reference numerals.

Although the present invention has been described above with reference to embodiments, the present invention is, of course, not limited to these embodiments, and can be modified in various ways without departing from the spirit of the invention. be.

[Brief explanation of the drawing]

FIGS. 1 and 2 are a vertical cross-sectional diagram and a cross-sectional plan view of a first embodiment of a column-beam joint in a reinforced concrete rigid frame structure according to the present invention, and FIGS. 5 and 6 respectively show a vertical cross-sectional diagram and a cross-sectional plan view of the third embodiment of the present invention.
FIGS. 7 and 8 are a vertical sectional view and a cross-sectional plan view, respectively, of a fourth embodiment of the present invention. Prisoner: Column, (B): Beam, (α) high-strength concrete, 9th is fiber-reinforced concrete, (b): Ordinary concrete, (1): Column main reinforcement, (2) ... Beam main reinforcement, (3) ... Concrete joint between column and joint, (
4)... mesh hardware, (5)... splint, (6)...
・X-type reinforcement agent Patent attorney Shige Okamoto 2 other people

Claims (3)

[Claims] (1) At the column-beam joint in a reinforced concrete structure, high-strength concrete or steel fiber-reinforced concrete is poured into the column-beam joint space limited by mesh metal fittings buried inside the column and beam, and the A column-beam joint in a reinforced concrete rigid frame structure, which is characterized by arranging support reinforcements in close contact with the main beam reinforcement that passes through the space. (2) Column-beam joint in the reinforced concrete rigid frame structure set forth in claim 1, which is formed by pouring high-strength concrete or steel fiber reinforced concrete into the beam end plastic hinge portion in contact with the column-beam joint space. Department. (3) Claims 1 and 2, wherein reinforcing bars bent in an X shape are disposed in close contact with the main beam reinforcement in the beam end plastic hinge portion that contacts the column-beam joint space. Column-beam joints in reinforced concrete rigid frame structures described in .