JPH083236B2 - Reinforcement structure of reinforced concrete perforated beam and reinforcing metal fittings used therefor - Google Patents

Description

TECHNICAL FIELD The present invention relates to a reinforcing structure for a reinforced concrete perforated beam and a reinforcing metal fitting used therefor.

In this specification, the term "reinforced concrete" includes steel-framed reinforced concrete.

<Prior art> Reinforced concrete perforated beams are reinforced concrete beams that have through holes for passing water pipes, electric conduits, etc. I won't. Since the presence of the through-hole is a weak point for the reinforcement, especially regarding the diagonal shear force, the reinforcement against the diagonal shear force is mainly required.

As such a reinforcing structure or a reinforcing metal fitting, for example, Japanese Patent Publication No. 44-21260, Japanese Patent Publication No. 59-10454, Japanese Patent Publication No. 52-146925, Japanese Patent Publication No. 54-75117, and Japanese Utility Model Publication No. 55 have been conventionally used. -22402
Various things are known by the number etc.

For example, looking at Japanese Examined Patent Publication No. 59-10454, this reinforcing metal fitting is composed of an inner and outer multiple endless metal annular body and a plurality of connecting rods that connect these annular bodies to each other. By this, the workability is improved.

<Problems to be solved by the invention> However, the reinforcing metal fittings in Japanese Patent Publication No. 59-10454 are not the best ones. For example, in the case of steel reinforced concrete construction, as shown in FIG. 4, the gap W between the side edge of the shaped steel 21 arranged at the center and the main bar 7 is a normal beam.
Only about 20 to 25 mm. Therefore, the inner and outer multiple annular bodies 22 and the plurality of connecting rods made of the commonly used 12φ rebar are used.
The total thickness of the annular body 22 and the connecting rod 23 is 24 mm.
When the reinforcing metal fitting 24 that becomes
It can lead to almost impossible construction.

Specifically, the through-hole (shown as a sleeve 9 for forming the through-hole in the figure) is formed obliquely due to the relation of drainage gradient and the opening end thereof is above and below the beam, that is, the main bar 7
In many cases, in the case of such a case, in the case of the reinforcing metal fitting 24 having a ring or close to it and having the same size spread in all directions, the through hole (sleeve 9).
If the "cover thickness" required between the innermost annular body 22i and the innermost annular body 22i, that is, the thickness between the reinforcing bar and the concrete surface is ensured, the outermost annular body 22o and the connecting rod 23 are inevitable.
Is applied to the narrow gap W described above, which causes the above-described construction difficulty. Further, in some cases, it may protrude from the main bar 7. In this case, it is unavoidable that the outermost annular body 22o, which is the most effective for reinforcement, is cut and constructed on site. .

In addition, reinforcement of through-holes of reinforced concrete perforated beams is most effective by reinforcing against diagonal shear forces as described above, but with this reinforcing metal fitting, there is no consideration for that point, so to speak omnidirectionally. Since the reinforcing force is exerted on average, the reinforcing effect per unit material (rebar) amount is insufficient. In other words, the amount of material (reinforcing bar) required to obtain a certain reinforcing effect is large, which is wasteful, and the weight is heavy, so that the handleability is poor.

In view of such conventional circumstances, the present inventors have proceeded with the development of a reinforcing structure or a reinforcing metal fitting that has a more excellent reinforcing effect and is more excellent in handleability and workability than conventional ones. It was As a result, the invention was reached.

<Means for Solving the Problem> Specifically, in the present invention, an octagonal main reinforcing bar and a rectangular auxiliary reinforcing bar each having four long sides and four short sides alternately arranged. A reinforcing structure for reinforced concrete perforated beams using, where the main reinforcing bars are arranged around the through hole such that each long side is approximately 45 ° with respect to the line parallel to the length direction of the beam. The reinforcing bar is inscribed in the main reinforcing bar with its four sides parallel to the long sides of the main reinforcing bar, and at least a pair of facing vertices are welded to the short side of the main reinforcing bar. A reinforcing structure for a reinforced concrete perforated beam is provided (as reinforcing metal fittings used together with claims, arranged alternately, each of which is approximately 135
An octagonal main reinforcing bar having four long sides and four short sides forming an interior angle of °, and the four internal sides of the main reinforcing bar in parallel with each long side of the main reinforcing bar. Provided is a reinforcing metal fitting which is abutted and has at least a pair of facing vertices and a rectangular auxiliary reinforcing bar welded to a short side of a main reinforcing bar.

<Operation> In this reinforcing structure or metal fitting, the main reinforcing bar is arranged around the through-hole forming sleeve with the upper and lower short sides being parallel to the main reinforcing bar and the left and right short sides being parallel to the bar. The long side is approximately 45 ° with respect to the line parallel to the length direction of the beam.
To be. Therefore, each side of the auxiliary reinforcing bar is also approximately 45 ° with respect to the line parallel to the length direction of the beam.
As a result, the long side of the main reinforcing bar and the side of the auxiliary reinforcing bar cooperate to exert the reinforcing force against the diagonal shearing force, so that the reinforcing effect is efficiently exhibited, and therefore the superior reinforcing effect is achieved. Will be obtained.

 This point will be described more specifically as follows.

That is, when an oblique shearing force is applied, an oblique shearing crack is about to occur, but each side of the main reinforcing bar and the auxiliary reinforcing bar orthogonal to the shearing crack receives a tensile force to suppress the spread of the shearing crack. At this time, each side adjacent to each side orthogonal to the shear crack does not receive a tensile force, but rather plays a role of a fixing effect on each side that receives a tensile force, thereby cooperating in improving the reinforcing effect. ing. Moreover, the anchoring effect of the adjacent sides is that the at least a pair of facing apexes of the auxiliary reinforcing bar are welded to the short side of the main reinforcing bar, so that each side working for the anchoring effect is three-dimensionally integrated and more Has been elevated. In other words, in this reinforcing structure or metal fitting, the respective sides of the main reinforcing bar and the auxiliary reinforcing bar bear different roles in an organically cooperative manner, thereby exerting an excellent reinforcing effect. is there.

Further, in such a reinforcing structure or reinforcing metal fitting, it is further advantageous to weld the horizontal reinforcing bars to the corners of the auxiliary reinforcing bars facing the short sides of the main reinforcing bars.

That is, as described above, when a complicated force such as a tensile force or a fixing effect acts on each side, the auxiliary reinforcing bar tends to distort,
Since this tendency to distort can be suppressed by the presence of the horizontal streaks, a superior reinforcing effect can be obtained. Also,
The presence of the horizontal stripes makes the "cover thickness" around the through-hole more suitable, and in connection with the suitability of this "cover thickness", prevents cracks due to drying that may occur around the through-hole. It also works.

Further, the reinforcing structure or the reinforcing metal fitting is not only excellent in the reinforcing effect, but also an octagon having four long sides and four short sides, so that the construction is easier than the conventional one. The advantage is that it is an octagon, so when compared with a size that obtains the same reinforcing effect as the conventional one, the expansion to the main bar side is small, and even if the necessary "cover thickness" is secured, the main reinforcement Since the reinforcement does not get into the narrow gap W described above, it is easy to construct, and the short side of the main reinforcement can be fixed to the ribs parallel to it. Since the amount of streaks required for the reinforcing effect is smaller than that of conventional ones, it is light and not bulky and has the advantage of being easier to handle during storage and transportation.

<Embodiment> An embodiment of the present invention will be described below with reference to the drawings.
In the following description, the parts common to those described in the related art and the parts common to the respective embodiments will be denoted by the same reference numerals, and redundant description will be omitted.

First Embodiment (FIGS. 1 and 2) In the reinforcing structure of this embodiment, the reinforcing metal fitting 1 shown in FIG. 1 is used.

 The reinforcing metal fitting 1 includes a main reinforcing bar 2 and an auxiliary reinforcing bar 3.

The main reinforcing bar 2 is formed in an octagon having four long sides 5a to 5d and four short sides 6a to 6d alternately arranged, and as shown in FIG. 6a, 6c are arranged around the through-hole forming sleeve 9 with the main bars 7, 7 and the left and right short sides 6b, 6d in parallel with the ribs 8, 8 respectively. Each long side 5a with respect to the parallel line L
Each ~ 5d is about 45 °. That is, the long sides 5a to 5d and the short sides 6a to 6d respectively form an interior angle of 135 °.

At this time, the left and right short sides 6b and 6d are connected and fixed to the rib 8.

The auxiliary reinforcing bar 3 is formed in a quadrangle having four sides 3a to 3d, and a pair of facing vertices 3s, 3s are the upper and lower short sides 6a, 6c of the main reinforcing bar 2, that is, the main reinforcing bar 7 when set.
Are connected and fixed to the short sides 6a and 6c which are parallel to each other by welding, and the four sides are parallel to the long sides 5a to 5d of the main reinforcing bar 2 and are connected to the main reinforcing bar 2. It is inscribed. The other pair of vertices may also be fixed by welding as shown in the second embodiment described later. However, in this case, it is necessary to consider that the auxiliary reinforcing bar 3 will not be fully housed by heating by welding.

The horizontal reinforcing bars 10 and 11 are welded to the auxiliary reinforcing bar 3. The horizontal ribs 10 and 11 serve to improve the reinforcing effect as described later, but especially the lower horizontal rib 10 has a sleeve receiving portion 10.
s is bent and extended, and serves to support the sleeve 9.

One of the characteristics of the reinforcing metal fitting 1 or the reinforcing structure using the reinforcing metal fitting 1 is that the main reinforcing bar 2 is an octagon as described above. That is, of each side of the octagon, each long side that is approximately 45 ° with respect to the line L parallel to the length direction of the beam
5a to 5d have, by themselves, the most efficient reinforcing force against the diagonal shearing force, and each short side 6 of the main reinforcing bar 2
By connecting and fixing the vertices 3s and 3s of the auxiliary reinforcing bar 3 to a and 6c, the respective sides 3a to 3d of the auxiliary reinforcing bar 3 cooperate closely with the long sides 5a to 5d of the main reinforcing bar 2. In addition, a more efficient and stronger reinforcing effect against diagonal shearing force is exhibited.

 This point will be described more specifically as follows.

That is, when an oblique shearing force in the direction of about 45 ° is applied to the line L, an oblique shearing crack C is about to be generated, but each side 5a of the main reinforcing bar 2 and the auxiliary reinforcing bar 3 orthogonal to the shearing crack C. , 5c and 3a, 3c receive a tensile force to suppress the spread of the shear crack C. At this time, the sides 6a, 5b, 6c, 5d and 3b, 3d adjacent to the sides 5a, 5c and 3a, 3c orthogonal to the shear crack C do not receive tensile force, but rather receive tensile force. By taking the role of the fixing effect of each side 5a, 5c and 3a, 3c, it cooperates with the improvement of the reinforcing effect. Moreover, adjacent sides 6a, 5b, 6c, 5d and 3
The fixing effect by b and 3d is that the pair of facing vertices 3s and 3s of the auxiliary reinforcing bar 3 are welded to the short sides 6a and 6c of the main reinforcing bar 2, so that each side acting on the fixing effect is three-dimensionally structured. It is more integrated and higher. That is, in this reinforcing structure or reinforcing metal fitting 1, the respective sides of the main reinforcing bar 2 and the auxiliary reinforcing bar 3 have different roles, and organically cooperate with each other to exert an excellent reinforcing effect. There is something.
When the shear crack C is reversely inclined, each side works in the opposite way.

In addition, in such a reinforcing structure or reinforcing metal fitting 1,
The transverse stripes 10 and 11 provide the following advantages.

That is, as described above, the auxiliary reinforcing bar 3 tends to distort when a complicated force such as a tensile force or a fixing effect acts on each side, but the tendency to distort can be suppressed by the existence of the lateral streaks 10 and 11. Because of this, it is possible to obtain a superior reinforcing effect. In addition, the presence of the horizontal stripes 10 and 11 makes the "cover thickness" around the through hole more suitable, and there is a possibility that it may occur around the through hole in connection with the suitability of this "cover thickness". It also works to prevent cracks due to drying.

In addition, the lateral streaks 10 and 11 have a role of further improving the reinforcing effect and giving a sufficient reinforcing force as described above, but they are not necessarily indispensable in terms of obtaining the necessary reinforcing force. Can be omitted.

In addition, the fact that the main reinforcing bar 2 has an octagonal shape as described above is not only superior in terms of reinforcing effect, but also an advantage that construction is easier than conventional ones, that is, Since it is an octagonal shape as described above, when compared with a conventional size, the main reinforcement 7
The expansion to the side is small, and even if the necessary "cover thickness" described above is secured, the main reinforcing bar 2 does not get into the narrow gap W described above, so construction is easy and the main bar parallel to the stirrups 8 Since the short sides 6b and 6d of the reinforcing bar 2 can be fixed to the stirrup bar 8, there is an advantage that the fixing work is easy, or the amount of the bar is smaller than the conventional one for the same reinforcing effect. It is also light and not bulky, and has the advantage of being easier to handle during storage and transportation.

Second Embodiment (FIG. 3) In the reinforcing metal fitting 30 according to this embodiment, the auxiliary reinforcing bar 31 is the first.
Welding all the apexes of the auxiliary reinforcing bar 31 to the respective short sides 6a to 6d of the main reinforcing bar 2 without using the horizontal reinforcing bars 10 and 11 in the embodiment and instead having the connecting bars 32a to 32d. It is different from that of the first embodiment.

These connecting bars 32a to 32d are long sides 5a to 5d of the main reinforcing bar 2.
For connecting the middle part of the side and the middle part of each side 31a to 31d of the auxiliary reinforcing bar 31 so that each side 5a to 5d and 31a to 31d cooperate closely to exert a reinforcing effect. so,
Not only is each side of the auxiliary reinforcing bar 31 welded, but also each side of the main reinforcing bar 2 is welded. Further, among the four connecting ribs 32a to 32d, the connecting ribs 32b and 32c are designed to project inward longer than others for abutting and positioning with respect to the sleeve 9.

Incidentally, these connecting ribs 32a to 32d are similar to the horizontal ribs 10 and 11 in the first embodiment and have a function of further improving the reinforcing effect, but they are not necessarily indispensable and the omission thereof is omitted. However, it is not always necessary to weld both the main reinforcing bar 2 and the auxiliary reinforcing bar 31, and only one of the main reinforcing bar 2 and the auxiliary reinforcing bar 31 may be welded.

The following are the strength test results of the reinforced concrete perforated beam using the reinforcing metal fitting 30 of the second embodiment.

Test No. 1 is a case where the reinforcing metal fitting 30 is used at two places, and Test No. 2 is a case where the reinforcing metal fitting 30 is used at three places. Since the numerical values are for the ultimate shear strength, the calculated values are obtained by the "Hirosawa formula".

It can be understood that this result has a reinforcing effect 20 to 30% higher than the conventional one.

<Effects of the Invention> Since the reinforcing structure for a reinforced concrete perforated beam and the reinforcing metal fittings used therefor according to the present invention are as described above, they have the following effects.

(A) Since the reinforcing force is most strongly exerted against the diagonal shearing force, the most efficient reinforcing effect can be obtained.

(B) Since each long side of the main reinforcing bar and each side of the auxiliary reinforcing bar closely cooperate with each other to exert the reinforcing force against the diagonal shearing force,
A stronger reinforcing effect can be obtained.

(C) The construction is easier than the conventional one.

(D) For the same degree of reinforcing effect, the amount of streak is smaller than that of the conventional one, so that it is not light and bulky and is easy to handle during storage and transportation.

[Brief description of drawings]

FIG. 1 is a schematic side view of a reinforcing metal fitting according to the first embodiment, FIG. 2 is a schematic side view of a reinforcing bar to which the reinforcing metal fitting of the first embodiment is assembled, and FIG. 3 is reinforcement according to the second embodiment. FIG. 4 is a schematic side view of the metal fitting, FIG. 4 is a schematic side sectional view showing a state in which a conventional reinforcing metal fitting is attached to a reinforcing bar, and FIG. 5 is a schematic side view seen in the direction of the arrow V in FIG. 1, 30 ...... Reinforcing metal fitting 2 ...... Main reinforcing bar 3, 31 …… Auxiliary reinforcing bar 3a to 3d …… Side 5a to 5d …… Long side 6a to 6d …… Short side 9 …… Sleeve 10, 11 …… Horizontal line

Claims (4)

[Claims] 1. A long side and a short side, which are alternately arranged, are divided into four.
A reinforcing structure for a reinforced concrete perforated beam using an octagonal main reinforcing bar and a rectangular auxiliary reinforcing bar each having sides, the main reinforcing bar being a line whose long sides are parallel to the length direction of the beam. The auxiliary reinforcing bars are inscribed in the main reinforcing bar with the four sides parallel to the long sides of the main reinforcing bar, and are arranged around the through hole at about 45 °. ,
A reinforcing structure for a reinforced concrete perforated beam, characterized in that at least a pair of facing vertices are welded to the short sides of the main reinforcing bar. 2. The auxiliary reinforcing bar is welded with horizontal bars at least at respective corners facing the upper and lower short sides of the main reinforcing bar, and the lower horizontal bar is provided with a sleeve receiving portion. The reinforcing structure for a reinforced concrete perforated beam according to claim 1. 3. An octagonal main reinforcing bar having four long sides and four short sides, which are alternately arranged and each form an interior angle of about 135 °, and four sides each have a length of the main reinforcing bar. A reinforcing metal fitting which is inscribed in the main reinforcing bar in parallel with the sides and at least a pair of facing vertices are rectangular auxiliary reinforcing bars welded to the short sides of the main reinforcing bar. 4. A horizontal reinforcing bar is welded to at least a pair of opposing corners of the auxiliary reinforcing bar, and a sleeve receiving portion is extended to one of the horizontal reinforcing bars. 3) The reinforcing metal fitting described.