JPH0732642Y2 - Beam-column joint structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a beam-column joint structure using a precast concrete beam in a reinforced concrete structure.

(Prior Art) When joining a cast-in-place concrete or a precast concrete column and a precast concrete beam in the outer peripheral part of a conventional building frame, as shown in FIGS. 7 and 8, the precast in the span direction is performed. A beam lower main bar (a) embedded in a concrete beam (A) and an upper beam main bar (b) arranged on the beam (A) on site are projected in parallel to each other in the panel zone, and The projecting ends of the main bars (a) and (b) are bent at right angles so that the opposite ends abut at the center of the beam outside the panel zone, and the vertical bending pieces (a ') of the same.
The opposite ends of (b ') are welded (w) to form an anchor portion in the panel zone.

In the figure, (c) is the ribs of the beam (A), (d) and (e) are the column main bars and the stirrups of the columns (B), respectively, and (A ') is the precast concrete beam in the girder direction ( f) and (g) are the beam upper main bar and the beam lower main bar of the beam (A ′).

(Problems to be Solved by the Invention) In the above-mentioned conventional method, the beam lower main reinforcement (a) of the precast concrete beam (A) in the span direction is preliminarily projected into the panel zone in a predetermined shape, and is fixed at the projection position. On the other hand, the beam upper main bar (b) is the beam lower main bar (a)
However, since the ribs (c) project above the beam (A), there is no freedom in the up-down direction when arranging the main beam reinforcement (b). If the upper main bar (b) and the lower beam main bar (a) are bent and welded at right angles so as to abut at the center of the beam outside the panel zone, the processing accuracy of the reinforcing bar and the construction accuracy of the frame are not good. However, there is a problem in that it is difficult to settle and the cost is high due to welding.

The present invention was proposed in order to solve the problems of the prior art. The purpose of the present invention is to simplify the construction, improve the shear resistance of the panel zone, and increase the fixing force of the main fixing bar. The point is to provide a joint structure of columns and beams.

(Means for Solving the Problem) In order to achieve the above-mentioned object, a joint structure of pillars and beams according to the present invention is provided so as to project in parallel to each other in a panel zone where the pillars and beams on the outer periphery of the building frame are joined. Each end of the beam lower main bar embedded in the precast concrete beam in the span direction and the upper beam main bar that is laid on site on the same beam is bent vertically outside the panel zone and By arranging U-shaped horizontal reinforcing bars that sandwich the vertical bending pieces at the ends,
The panel zone is constructed by placing joint concrete.

(Operation) Since the present invention is configured as described above, an external force acts on the beam-column joint at the time of an earthquake or the like, and a pull-out force acts on the beam bar whose ends are vertically bent.

At that time, in the beam-column joint panel, it mainly resists the shearing force acting on the panel portion due to the compression strut force, and the resistance force against the pulling-out force of the beam reinforcement is mainly due to the bending of the upper and lower beam main reinforcements in the panel zone. It is obtained by the bearing force acting on the part, which bearing force is supported by the compression stratum force.

At this time, the vertical component force of the same compression strut force is resisted by the bending compressive stress of the column, and the horizontal component force is opposed by the horizontal resistance of each vertical bent piece of the upper and lower beam main bars.

When the horizontal resistance of each vertical bent piece is not sufficient, the same part is pulled out, but in the present invention, as described above, each panel zone of the upper and lower beam main bars in the precast concrete beam in the span direction. By arranging the U-shaped horizontal reinforcing reinforcing bar in the panel zone so as to sandwich the vertical bending piece of the inward projecting end part, the horizontal resistance of the fixing end part of the upper and lower beam main bars is increased, The fixing force in the panel zone at the fixing end is increased.

(Embodiment) The present invention will be described below with reference to the illustrated embodiment.

(A) is a precast concrete beam that is joined to the cast-in-place concrete or precast concrete column (B) at the outer periphery of the frame, and (A ') is a girder precast concrete beam.

(1) is a beam lower main bar embedded in the beam (A), (2) is a beam upper main bar which is arranged on the beam on the spot, and both main bars (1)
(2) are projected in parallel to each other in the panel zone, and vertical bent pieces (1a) and (2a) are bent outside the panel zone.

In the figure, (3) is the rib of the beam (A), (4) is the main column of the column (A), and (5) is the stirrups. (6) is a U-shaped horizontal reinforcing bar so that the vertical bending pieces (2a) of the beam upper main bar (2) and the beam lower main bar (1) as well as (1a) are sandwiched in the panel zone. It is installed in.

In the illustrated embodiment, the U-shaped horizontal reinforcing bars (6) sandwich the vertical bending pieces (1a) (2a) of the adjacent beam upper and lower main bars (1) and (2). , Each of the vertical bending pieces (1a) (2a) may be mounted separately.

After arranging the U-shaped horizontal reinforcing bar (6),
Placing steel fiber reinforced concrete in the panel zone,
Slab reinforcement is laid on the beam (A) and slab concrete is placed.

In the figure, (7) and (8) are the upper and lower beam main bars of the precast concrete beam (A ') in the girder direction projecting into the panel zone.

At the beam-column joint outside the frame, axial force Nc, bending moments Mc, Mb, and shearing force Qc act as shown in FIG. 4, and the fixing end is vertically bent at the upper and lower sides of the beam. A pulling force acts on the main muscle. Note that this pulling force acts on either the upper beam or lower beam depending on the direction of the earthquake.

At this time, the beam-column joint panel mainly resists the shearing force acting on the panel due to the compression strut force.

The column concrete resists the axial force.

Therefore, the anchoring force of the beam upper and lower main bars is determined by the horizontal protrusion of the main bar.
It is obtained by the adhesive force of {circle around (3)}, the supporting pressure of the curved portion {circle around (1)}, and the adhesive force of the vertical bent piece portion {circle over (R)}, and these resist the pulling force.

However, the adhesive force of the horizontal protruding portion (3) is not large because bending cracks are generated in the column, and the pulling force of the beam main bar is mainly resisted by the supporting pressure between the curved portions (3).

Thus, the bearing pressure between the above-mentioned {circle around (1)} is supported by the compression stratum force. At this time, the vertical component of the compression force is resisted by the bending compressive stress of the column, and the horizontal component is resisted by the horizontal resistance of the vertical bending piece.

When the horizontal resistance of the vertical bent piece is weak, the beam main bar comes out as shown in FIG. 5, and at the same time, the vertical bent piece jumps out. Therefore, in order to prevent the beam main bar from slipping out and bouncing off, it is necessary to increase the horizontal resistance.

However, in the present invention, the upper and lower beam main bars (1)
Since the U-shaped horizontal reinforcing bars (6) are arranged so as to sandwich the vertical bending pieces (1a) and (2a) provided at the protruding end in the panel zone in (2), The horizontal resistance of the bent pieces (1a) (2a) is increased, the fixing force of the fixing ends in the panel zones of the upper and lower beam main bars (1) and (2) is increased, and the seismic resistance of the frame is improved. .

Furthermore, when steel fiber reinforced concrete is cast as joint concrete in the panel zone, the shear strength of the beam-column joint is increased and the anchoring force of the upper and lower beam main bars (1) and (2) is further increased. is there.

(Effects of the Invention) According to the present invention, as described above, a beam lower main bar embedded in a span direction precast concrete beam projecting in a panel zone that joins column beams on the outer periphery of a building frame and , The vertical bending without bending and welding the opposite ends of the vertical bending pieces formed by bending each end of the main reinforcement on the beam on-site at the top of the same beam without welding. U-shaped horizontal reinforcing bars that sandwich the pieces are placed and concrete is placed in the panel zone to increase the horizontal resistance of the vertical bent pieces, and the main bars of the upper and lower beams are fixed at the beam-column joints. In addition to increasing the strength and improving the seismic resistance of the frame, the anchoring work in the panel zones of the upper and lower beam main bars is greatly simplified, and the anchoring of the large diameter beam main bars is made possible, facilitating the reinforcement work. is there.

[Brief description of drawings]

FIG. 1 is a longitudinal sectional view showing an embodiment of a beam-column joining structure according to the present invention, FIG. 2 is a cross-sectional plan view thereof, FIG. 3 is a perspective view of a U-shaped horizontal reinforcing bar, and FIGS. FIG. 6 is an explanatory view of the operation of the present invention, and FIGS. 7 and 8 are longitudinal sectional views and transverse plan views showing an example of a conventional beam-column joint structure, respectively. (A) …… Pillar, (B) …… Beam, (1) …… Beam under beam,
(1a) …… Vertical bent piece, (2) …… Main beam reinforcement, (2a)…
… Vertical bent pieces, (6) …… U-shaped horizontal reinforcing bars.

Claims (1)

[Scope of utility model registration request] 1. A beam lower main bar embedded in a span direction precast concrete beam projecting parallel to each other in a panel zone connecting column beams on the outer periphery of a building frame, and on-site bar arrangement on the beam. Each of the ends of the above-mentioned beam upper main bar is bent vertically outside the panel zone, and U-shaped horizontal reinforcing bars that sandwich the vertical bent pieces of the upper and lower main bars are arranged. A joint structure of columns and beams, which is made by placing joint concrete in the panel zone.