JPH01154923A - Joining section of reinforced concrete post and beam - Google Patents

Abstract

PURPOSE: To increase shearing strength by placing a concrete having higher strength than that of a concrete in a column and a beam in a joint space between a column and a beam partitioned by a net hardware and forming a main beam reinforcement past the joint space with its diameter larger than the diameter of the main beam reinforcement. CONSTITUTION: A recess 1a provided at one side edge of a net hardware 1 so as to be engaged with a main beam reinforcement is engaged with the main beam reinforcement 4 and the side edges of the adjacent hardwares 1 are lapped and combined with each other in a feather lapped manner to form a joint space between a column A and a beam B. The main beam reinforcement 4 is formed in the joint space between the column A and the beam B with its diameter 4a larger than that of the main beam reinforcement 4 in a beam member. A concrete C having higher strength than that of a concrete used for the column A and the beam B is placed in the joint space between the column A and the beam B to constitute a joint between the column A and the beam B. In this way, the high-strength concrete C placed in the joint space between the column A and the beam B and the concrete in the beam member are formed in one unit.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a joint between reinforced concrete columns and beams.

(Prior technology) Conventionally, 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 through reinforcement, and in normal design, a plastic hinge is created at the end of the beam so that the boarding and disembarking is not possible. It is designed to be a prone mechanism.

(Problem to be solved by the invention) When a strong seismic force acts on such a rigid frame,
A large shearing force acts on the column-beam joint, causing shear cracks in the joint, reducing shear rigidity, and repeated loading acts on the beam and column main reinforcement, especially in the beam main reinforcement, which is generated from the beam end. As the yielding progresses toward the beam members, it also progresses within the columns, beams, and joints.

As the yielding of the main reinforcement of the beam progresses into the joint between the column and the beam, the adhesion force between the main reinforcement and the joint concrete deteriorates significantly, and the amount of pullout of the main reinforcement of the beam from the joint increases gradually.

This phenomenon tends to become more and more prominent as buildings become taller in recent years, and high-strength, large-diameter main reinforcing bars are arranged in high density.

In other words, the shear stress at the joint between columns and beams becomes significantly higher,
Structural conditions are severe. Furthermore, by using large-diameter, high-strength main reinforcing bars, the adhesion force of the main reins to the concrete at the joints will be significantly degraded.

This condition reduces the energy absorption capacity of the plastic hinge portion at the end of the beam, reducing the seismic safety of the rigid frame structure, which is designed to ensure seismic resistance through plastic deformation.

(Means for Solving the Problems) The present invention was proposed in order to solve the above problems. A reinforced concrete column characterized in that high-strength concrete or steel fiber-reinforced concrete is cast, and the diameter of the main beam reinforcement passing through the joint space is larger than the diameter of the main beam reinforcement inside the beam member. , relating to the joints of beams.

(Function) In the present invention, as described above, the column/beam joint space partitioned by mesh metal fittings is made of high-strength concrete or steel fiber reinforced concrete, so that the shear strength of the column/beam joint is This not only prevents a decrease in shear rigidity due to earthquake loads in the same area, but also
The strength of the main reinforcement of the column and beam passing through the column and beam joint space increases, the deterioration of the strength of the main reinforcement due to repeated loads during earthquakes is reduced, and the amount of the main reinforcement that can be extracted from the joint of the column and beam increases. decreases.

In addition, by increasing the diameter of the main beam reinforcement in the column/beam joint space, the yielding of the beam main reinforcement does not progress into the column/beam joint, and this increases the attachment force of the beam main reinforcement within the column/beam joint. Therefore, deterioration of the adhesion force of the beam main reinforcement to the concrete at the joint due to repeated loads during an earthquake is prevented, and the amount of the beam main reinforcement pulled out from the column and beam joint is significantly reduced.

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

(1) is a rectangular net-like hardware having the same height as the beam, and a recess (1a) that engages with the main beam is provided on the negative side edge.

(A) is a reinforced concrete column, (2) is the main reinforcement of the column, (
3) is a stirrup.

(B) is a reinforced concrete column, (4) is a beam main reinforcement, (
Reference numeral 5) denotes a rib, and the main beam reinforcement (4) is formed in a larger diameter portion (4a) than the main beam reinforcement in the beam member in the column-beam joint space.

Then, the side edge concave portion (1a) of the mesh hardware (1) is engaged with the beam main reinforcement (4), and the mesh hardware (1) is connected to the adjacent mesh hardware (1).
) are overlapped in a layered manner, and the respective mesh-like hardware (1) are bound together with constraining reinforcing bars (6), thereby dividing the column-beam joint space with the mesh-like hardware (1).

In this way, the column and beam joint space divided by mesh metal fittings (1) is filled with concrete that has a higher strength than the concrete used for the column (8) and beam (B) members, or is equivalent to or has a higher strength than the concrete used for the column (8) and beam (B) members. The column and beam joints are constructed by pouring high-strength steel fiber reinforced concrete (C).

According to the illustrated embodiment, as described above, the mesh hardware (1)
Since high-strength concrete or steel fiber reinforced concrete (C) is placed in the column/beam joint space divided by The main reinforcements (2) (4) of the columns (A) and beams (B) passing through the joint space are prevented from decreasing.
The adhesion strength against concrete is increased, the deterioration of adhesion force due to repeated loads during earthquakes is reduced, and the amount of each of the main reinforcements (2) and (4) pulled out from the column and beam joints is reduced.

In addition, the main beam reinforcement (4) is located at the large diameter part (
4a), the yielding of the main beam reinforcement (4) does not extend into the joint between the column and beam, and together with the increase in the attachment force of the main beam reinforcement (4) within the joint, the yielding of the main beam reinforcement (4) during an earthquake. This prevents deterioration of the attachment force due to repeated loads in the main beam reinforcement (4).
The amount of extraction from the column and beam joints is significantly reduced.

(Effects of the Invention) According to the present invention, the joint space between reinforced concrete columns and beams is divided by mesh metal fittings, and concrete with a higher strength than the concrete of the column and beam members or steel fiber reinforced concrete is placed in the same space. At the same time, by forming the diameter of the main beam reinforcement passing through the joint space to be larger than the diameter of the main beam reinforcement inside the beam member, the shear strength of the column-beam connection is increased and shear caused by earthquake loads in the gap is increased. Prevents decrease in rigidity,
By increasing the attachment strength of the main reinforcement passing through the joint, especially the main beam reinforcement, it is possible to prevent the main reinforcement from being pulled out of the joint and increase the energy absorbed by the plastic hinge at the end of the beam. This can improve the earthquake resistance of reinforced concrete rigid frame structures.

Note that the space at the column/beam joint is divided by mesh hardware embedded in the beam, so the high-strength concrete or steel fiber-reinforced concrete cast in the column/beam joint space and the concrete of the beam member are separated. and are integrated.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing an embodiment of the joint between a reinforced concrete column and a beam according to the present invention, Fig. 2 is a cross-sectional plan view thereof, Fig. 3 is a front view of mesh metal fittings, and Fig. 4 is a beam FIG. 5 is a longitudinal cross-sectional view showing a portion for attaching the mesh hardware to the main reinforcement, FIG. 5 is a joint cross-sectional side view thereof, and FIG. 6 is a cross-sectional plan view thereof. (A)---Reinforced concrete column, (B)---Reinforced concrete beam, (c) -High strength concrete or steel fiber reinforced concrete, (1)-
Mesh hardware, (4) - Main beam reinforcement, (4a) - Large diameter section of single beam main reinforcement Patent attorney Shige Okamoto 2 people outside of the text Ka 5 Figure

Claims (1)

[Claims] Concrete with higher strength than the concrete of the column and beam members,
Or a reinforced concrete column or beam joint, characterized in that steel fiber reinforced concrete is cast and the diameter of the beam main reinforcement passing through the joint space is made larger than the diameter of the beam main reinforcement within the beam member. .