JP2566399Y2 - Precast concrete beams - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a precast concrete beam.

[0002]

2. Description of the Related Art Precasting of reinforced concrete columns, beams, walls, floor slabs, and the like has been advanced in order to compensate for an extreme labor shortage in recent years or to improve workability and economy. Among them, the precast concrete beam 10 is, as shown in FIG.
The post-cast concrete 30 is cast at 0, and these are connected by stirrups 40 projecting from the upper surface of the precast concrete 20.

[0003]

However, in the case of such precast concrete beams, when the building is greatly deformed due to an earthquake or the like, the joint interface between the precast concrete and the post-cast concrete is mutually changed by the external force P shown in FIG. There is a drawback that the precast concrete and the post-cast concrete lose their integrity due to a shift or separation, and a predetermined strength and rigidity are lost. Therefore, as a means for preventing such a defect, a method of arranging the stirrups densely as described above is conceivable, but this not only deteriorates the workability but also requires the use of an extra reinforcing bar other than the slip prevention. It was uneconomical because we could not get it. The present invention has been made in view of such a problem, and an object of the present invention is to provide a precast concrete beam in which a joint interface between precast concrete and post-cast concrete does not shift even during a large deformation of a building due to an earthquake or the like. To provide.

[0004]

The precast concrete beam of the present invention for achieving the above object has a stirrup whose upper part projects from the upper surface of the precast concrete .
In precast concrete beams, the stirrups
A U-shaped reinforcement is attached along the top, with the opening facing down.
Reinforcement, the lower part of the reinforcement is precast concrete
It is characterized by being buried in .

[0005]

[Function] By providing reinforcing bars along the stirrups protruding from the upper surface of the precast concrete, it is possible to increase the amount of rebar connecting the precast concrete and the post-cast concrete by extremely simple work. As it is possible, it is very effective in preventing the slippage of detached concrete cast into precast concrete beams and preventing it from falling off, as if the amount of stirrups was increased, improving the strength and toughness during large deformation of the building Can be achieved. In addition, since the reinforcing bars are U-shaped and attached to the stirrups, the space between the upper surface of the precast concrete and the stirrup tops can be effectively used, so that the upper main bars of the beam can be easily arranged. In addition, since the embedding length of the reinforcing bar in the precast concrete is set to be 10 times as long as the diameter of the reinforcing bar, the work of attaching the reinforcing bar to the stirrup can be performed extremely easily.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the precast concrete beam of the present invention will be described in detail with reference to the drawings. FIG.
FIG. 2 is a perspective view of the precast concrete beam of the present invention, FIG. 2 is a cross-sectional view of the precast concrete beam, and FIGS. 3 to 7 are cross-sectional views illustrating a method of manufacturing the precast concrete beam. The upper part of the stirrup 2 of the precast concrete beam 1 protrudes from the upper surface of the precast concrete 1a, and a U-shaped reinforcing bar 3 is attached along the protruding stirrup 2 by a binding wire 3a. The reinforcing bars 3 have the same diameter as the stirrups 2, and the length of embedding in the precast concrete 1a is set to 10 times the diameter.

As described above, the stirrups 2 are reinforced by the U-shaped reinforcing bars 3, so that the post-cast concrete 1b cast into the precast concrete beam 1 is prevented from slipping.
Alternatively, the displacement can be reduced.

Next, a method for manufacturing the precast concrete beam 1 will be described with reference to FIGS. First, the stirrups 2 are arranged at required intervals along the long side direction of the lower main reinforcement 4 of the beam. Next, a U-shaped reinforcing bar 3 is attached above these stirrups 2 by a binding wire 3a. Then, a pre-cast concrete beam 1 is formed by attaching a form to the reinforcing bar 6 provided with the reinforcing bars 3 and placing concrete. As a result of casting the concrete, the embedding length of the reinforcing bar 3 is one of its diameter.
The length is 0 times. The precast concrete beam 1 so produced after bridging the pillars in the field, the upper portion main reinforcement 5 in the stirrups 2 and reinforcement 3 is Haisuji. Then, post-cast concrete 1b is poured into the precast concrete 1a, and these are stirrups 2
And the reinforcing bars 3.

[0009]

[Effect of the Invention] By providing reinforcing bars along the stirrups projecting from the upper surface of the precast concrete, the amount of rebar connecting the precast concrete and the post-cast concrete can be increased with extremely simple work. As if the amount of stirrups was increased, it is extremely effective in preventing and preventing slippage of post-cast concrete cast into precast concrete beams, and aims to improve the strength and toughness during large deformation of the building be able to.

[0010] By providing the reinforcing bars with a U-shape and attaching them to the stirrups, the space between the upper surface of the precast concrete and the stirrup tops can be effectively used, so that the upper main bars of the beam can be easily arranged.

Since the embedding length of the reinforcing bar in the precast concrete is set to be 10 times as long as the diameter of the reinforcing bar, the work of attaching the reinforcing bar to the stirrup can be performed extremely easily.

[Brief description of the drawings]

FIG. 1 is a perspective view of a precast concrete beam.

FIG. 2 is a sectional view of a precast concrete beam.

FIG. 3 is a cross-sectional view in which stirrups are arranged on a lower main bar of a beam.

FIG. 4 is a cross-sectional view of a stirrup with reinforcing bars attached thereto.

FIG. 5 is a sectional view of a precast concrete beam.

FIG. 6 is a cross-sectional view in which upper main reinforcing bars are arranged on stirrups of a precast concrete beam.

FIG. 7 is a sectional view in which post-cast concrete is cast on a precast concrete beam.

FIG. 8 is a sectional view of a conventional precast concrete beam.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Precast concrete beam 1a Precast concrete 2 Stirrup 3 Reinforcing bar

 ──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-3-66857 (JP, A) JP-A-60-133146 (JP, A) JP-B-53-20762 (JP, B2)

Claims (2)

(57) [Scope of request for utility model registration] From [claim 1] the top surface of the precast concrete Oh
Precast concrete beams with protruding streaks
In addition, a U-shaped reinforcement is provided along the stirrup.
With the opening on the lower side, and the lower part of the reinforcement is
Precast concrete beams buried in precast concrete. 2. Precast concrete for said reinforcing bars
The length of embedding in the tube is 10 times the diameter of the reinforcing bar
The precast concrete beam according to claim 1, characterized in that: