JP2640302B2 - Reinforced concrete beam reinforcement structure - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a reinforcing bar structure of a reinforced concrete beam, and more particularly, to a reinforcing bar structure of a main reinforcing bar of a reinforced concrete beam in which a through-hole for equipment piping or the like is to be formed.

[0002]

2. Description of the Related Art Conventionally, as shown in FIGS. 4 (a) and 4 (b), a beam main reinforcement 21 is provided from the side as a reinforcing structure of a reinforced concrete beam in order to improve the shear strength of the beam and secure seismic performance. An X-shaped reinforcing bar 20 that crosses into an X-shape is adopted. The X-shaped reinforcing bar 20 can prevent the adhesive splitting fracture at the same time, and is particularly effective for the short span reinforced concrete beam 22 in which the adhesive splitting fracture easily occurs. That is, at the center of the span where adhesion splitting is likely to occur, the concrete breaking length per one reinforcing bar 23 arranged in parallel with the beam ((beam width) / (number of reinforcing bars at upper and lower ends of the beam)) is displayed. 3) to make the entire split mode 24 penetrate all the lower main bars shown in FIG.
Fig. 3 (b), which prevents the occurrence of cracks and has a larger adhesion strength
In this case, the toughness and the like of the reinforced concrete beam 22 are improved in the corner splitting mode 25 shown in FIG.

On the other hand, a reinforced concrete beam may be provided with a through hole 26 for facility piping or the like. In addition, it is preferable that the through-hole 26 is usually provided at the center of the span where the stress level is low.

[0004]

However, the above X
In the reinforced concrete beam 22 having the reinforcing bars 20, it is difficult to provide the through hole 26 at the center of the span because the reinforcing bars intersect at the center of the beam. Further, as shown in FIG. 4 (a), when the through holes 26 are arranged avoiding the intersections of the X-shaped reinforcing bars 20, the through holes 26 are disposed near the ends of the span where the stress level is high.
Which is not preferable from the viewpoint of securing proof stress and toughness. Further, as shown in FIG. 4 (b), when all the upper and lower beam main reinforcements 23 are arranged in parallel with the beams and the through hole 26 is arranged at the center of the span, the X-type reinforcement having excellent seismic performance is used. There is a problem that the advantage is not utilized and a beam structure with poor adhesion strength and toughness is formed due to the occurrence of the adhesion splitting in the above-mentioned splitting mode 24.

Accordingly, the present invention has been made to solve the above problems, and has the same seismic performance as that of X-type reinforcing bars by improving the adhesive strength and toughness, and has a low stress level at the center of the span. The aim is to provide a reinforced concrete beam reinforcement arrangement that allows the installation of through holes.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned object, and its gist is, for example, a reinforcing bar structure of a reinforced concrete beam in which a through hole for equipment piping is to be formed, At least one beam lower main bar and beam upper main bar except for each beam main bar located at both ends of the first stage beam lower main bar and beam upper main bar disposed at the upper and lower ends of the reinforced concrete beam, It is bent and arranged so as to have a parallel portion protruding in a substantially equilateral trapezoidal shape toward the center in the vertical direction of the beam via the inclined portions at both ends, and between the parallel portion of the main bar at the lower end of the beam and the parallel portion of the main bar at the upper end of the beam. Has a reinforcement structure of a reinforced concrete beam in which the through holes are arranged.

Here, the parallel portions extend from the beam main reinforcing bars projecting from the positions of the beam main reinforcing bars at the upper and lower ends in parallel with each other. In addition, the beam main reinforcement to be bent is preferably a position where the second-level main reinforcement is disposed or the beam is located at a position where the second-level main reinforcement is arranged, in the case where the parallel portion is a two-level reinforcement at the lower end main reinforcement and the upper end main reinforcement of the beam. Bend so that it is located at the center in the vertical direction. And more preferably, it may be bent so that the parallel portion is located near the through hole to be formed. In addition, the inclined portion for projecting the parallel portion does not necessarily need to be inclined from the end of the beam, and is bent obliquely after a predetermined length of the parallel portion with the beam is provided to secure a predetermined fixing length. Or a part thereof may be buried in a reinforced concrete column.

[0008]

According to the reinforcing structure of the reinforced concrete beam of the present invention,
Since the main bar at the lower end of the beam and the main bar at the upper end of the beam are disposed obliquely at the end of the beam having a high stress level, the shear strength of the beam is improved in the same manner as in the case of the X-type reinforcing bar. In addition, since the parallel part of the beam bottom main bar and the beam top main bar at the center of the beam protrudes toward the center in the vertical direction, the concrete breaking length of the beam bottom main bar and the beam top main bar arranged parallel to the beam at the center of the span is reduced. By reducing the size, the mode of the adhesive splitting is kept in the corner splitting mode, and the toughness of the reinforced concrete beam is improved.
In addition, a gap equal to or larger than the diameter of the through-hole is maintained between the parallel portion of the main beam at the lower end of the beam and the parallel portion of the main bar at the upper end of the beam, so that the through-hole can be provided at the center of the span.

If the main bar at the lower end of the beam and the main bar at the upper end of the beam are bent so that the parallel portion is located near the through hole to be formed, these reinforcing bars also act as opening reinforcing bars.

[0010]

Next, an embodiment of the present invention will be described in detail with reference to the accompanying drawings.

FIG. 1 (a) is a side view and FIG. 1 (b) is a cross-sectional view of the present embodiment.
In the reinforced concrete beam 11 erected between the reinforced concrete columns 10, a through hole 12 for equipment piping is provided at the center of the span where the stress level is low. That is, of the beam lower main bars 13 and the beam upper main bars 14 disposed at the upper and lower ends of the reinforced concrete beam 11, the two beam lower main bars 13 excluding the beam main bars 13 'and 14' located at both ends. And the upper beam main reinforcement 14 is bent and bent, and protrudes toward the center in the vertical direction of the beam via the inclined portions 15 of the lower beam main reinforcement 13 and the upper beam main reinforcement 14, and between the parallel portions 16 vertically opposed to each other. A through hole 12 is provided.

The lower beam main reinforcing bar 13 and the upper beam main reinforcing bar 14 are bent at the diagonal direction of the reinforced concrete beam 11 while the inclined portions 15 located at both ends of the span are bent. A parallel part 16 extending parallel to the reinforced concrete beam 11 is formed while projecting at a height different from 13 ′ and 14 ′. That is, the parallel part 1
6 has an equilateral trapezoidal shape together with the inclined portion.

Here, the parallel portion 16 is formed by the main bar 1 at the lower end of the beam.
In the case where the third main reinforcing bar 14 and the beam upper main reinforcing bar 14 are arranged in two steps, the second stage, that is, the position where the inner beam main reinforcing bar is disposed (the reinforcing bar diameter of the first main beam reinforcing bar located at the upper and lower ends, The position is determined according to the correlation with the aggregate diameter of the concrete to be formed). The parallel portion 16 extending from the beam lower main bar 13 and the beam upper main bar 14 extending in parallel.
Between them is sufficient, where, for example, beam
The through hole 12 having a diameter of about 1/4 of the diameter is formed.
The parallel portion 16 has a beam lower main bar 13 and a beam upper main bar 1.
4, reinforcing stirrups 18 are arranged at predetermined intervals around the beam main reinforcing bars 13 ', 14' on both side ends, and stirrups 18 are arranged at predetermined intervals around them.

In the reinforcing structure 30 of the reinforced concrete beam 11 having such a configuration, the beam lower main bar 13 and the beam upper main bar 14 are disposed obliquely at the end of the beam having a high stress level. Improve the shear strength of the beam as well as the reinforcement. Furthermore, since the parallel portion 16 of the beam lower main bar 13 and the beam upper main bar 14 protrudes toward the center in the vertical direction at the center of the span of the beam, the beam lower main bar 13 arranged in parallel with the beam is provided.
And the beam main reinforcements 14 ', 1' at the both ends.
Only 4 'is obtained. As a result, the toughness equivalent to that of the X-type reinforcing bar can be obtained by reducing the concrete breaking length and preventing the occurrence of the all split mode. That is, even if a through hole is provided in the center of the span, the same seismic performance as that of the X-type reinforcing bar can be maintained.

The side view of FIG. 2A and the cross-sectional view of FIG. 2B show another embodiment of the present invention. In the bar arrangement structure 30 according to this embodiment, the inclined portion 15 is formed as shown in FIGS.
In this embodiment, the parallel portion 16 is disposed proximate to the through hole 12. And, in the same manner, the parallel section 1
6, reinforcing reinforcing bars 17 are provided on the beam main reinforcing bars 13 ', 1 on both side ends.
A stirrup 18 is disposed around 4 ′, and the parallel portion 16 bears a part of the stress concentrated around the through hole 12 and also serves as an opening reinforcing bar.

[0016]

As described above, in the reinforcing bar structure of a reinforced concrete beam according to the present invention, the main bar at the lower end of the beam and the main bar at the upper end of the beam are formed with a parallel portion projecting toward the center in the vertical direction of the beam via the inclined portions at both ends. Since it is bent and arranged so as to have, and through holes are arranged between the parallel parts of each beam main reinforcement, the adhesion strength and toughness of reinforced concrete beams are improved compared to parallel reinforcement,
Reinforced concrete beam structure that maintains seismic performance equivalent to that of X-type reinforcing bars and enables the installation of through holes in the center of the span with low stress levels, making it possible to stabilize reinforced concrete beams where through holes should be drilled. Can be provided easily.

[Brief description of the drawings]

FIG. 1A is a side view showing an embodiment of a reinforcing bar arrangement structure of a reinforced concrete beam, and FIG. 1B is a cross-sectional view along AA of FIG.

FIG. 2A is a side view showing another embodiment of a reinforcing bar structure of a reinforced concrete beam, and FIG. 2B is a cross-sectional view taken along BB of FIG.

FIGS. 3A and 3B are cross-sectional views showing the mode of adhesive splitting of a reinforced concrete beam, wherein FIG. 3A shows an all splitting mode, and FIG. 3B shows a corner splitting mode.

FIG. 4 (A) is a side view showing a reinforcing bar structure of a conventional reinforced concrete beam using X-shaped reinforcing bars, and (B) is a CC of (A).
FIG.

FIG. 5A is a side view showing a reinforcing bar structure of a conventional reinforced concrete beam with parallel reinforcing bars, and FIG. 5B is a DD line of FIG.
FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 11 Reinforced concrete beam 12 Through-hole 13 Beam bottom main bar 13 'Beam bottom main bar (both ends) 14 Beam top main bar 14' Beam top main bar (both ends) 15 Inclined portion 16 Parallel portion 30 Reinforcement structure

Claims (1)

(57) [Claims] 1. A reinforcing bar structure for a reinforced concrete beam having a through hole, wherein a beam lower reinforcing bar and a beam upper reinforcing bar disposed at upper and lower ends of the reinforced concrete beam are connected to each other at both ends. At least one of the removed beam bottom main bars and the beam top main bars is bent and arranged so as to have a parallel portion protruding toward the center in the vertical direction of the beam via the inclined portions at both ends, and a parallel portion of the beam bottom main bar. A reinforcing bar structure for a reinforced concrete beam, wherein the through-hole is arranged between the reinforcing bar and a parallel portion of a main bar at the top of the beam.