JP6262459B2 - Reinforcing bar unit and reinforced concrete structure - Google Patents

Description

  The present invention relates to a reinforcing bar unit constituting a reinforced concrete beam or a reinforced concrete column of a building.

  Buildings using reinforced concrete beams and reinforced concrete columns are widely used due to demands for reduction of construction costs and on-site construction. Conventionally, such bar arrangement in reinforced concrete is generally performed by processing and assembling the reinforcing bar in the field.

  However, rebar processing and assembly is an operation that requires skill. Therefore, quality varies depending on workers at each site, and there is a risk that the finishing accuracy and strength will be insufficient. For this reason, some measures have been taken to equalize quality by making the reinforcing bars unitized in the factory in advance and transporting them to the site to use them, eliminating the need for processing and assembly of the reinforcing bars at the site. ing.

  In order to unitize a reinforcing bar, a method of fastening a plurality of reinforcing bars using a fastening member called a hook or a binding bar is known. However, in order to make sure that the reinforcing bars and the surrounding concrete are in close contact with each other and to improve the strength by making the concrete used for the beams and columns dense, instead of using hooks etc. that may interfere with the close contact, It is preferable to unitize the reinforcing bars by welding (for example, Patent Document 1).

JP 2002-285678 A

  However, when the reinforcing bar is heated by welding work at a portion where the reinforcing bars intersect, transformation occurs in the reinforcing bar material at the heated location. This transformation increases the hardness of the reinforcing bars while decreasing the toughness. Therefore, the reinforced concrete structure that resists the tensile force from the outside by the internal reinforcing bars may not satisfy the strength and toughness required for the beams and columns.

  In addition, measures can be considered in which each portion is welded while being managed so that the reduction in the toughness of the reinforcing bars is kept within a range that is acceptable for satisfying the required performance as a beam or column. However, there is a problem that it takes a lot of labor and time to perform welding with such management at all the intersections of a plurality of reinforcing bars.

  The present invention has been made in view of such problems, and the purpose thereof is to improve the work efficiency in the field by unitizing the reinforcing bars, but without requiring a great effort in the management of welding and high strength. It is in providing the reinforcing bar unit which can ensure toughness.

  In order to solve the above-described problem, a reinforcing bar unit according to the present invention includes a plurality of main bars that are spaced apart from each other and extend substantially parallel to the first direction, and extend so as to intersect the plurality of main bars, and in the first direction. A plurality of shear reinforcement bars arranged to be spaced apart from each other, and each of the plurality of shear reinforcement bars is a part of a plurality of intersections at a crossing position with the plurality of main bars. It has the welding part welded with respect to the said main reinforcement in a part, and has the non-welded part which is not welded with respect to the said main reinforcement in another crossing part.

  In the reinforcing bar unit according to the present invention, each of the shear reinforcing bars has a welded portion that is welded to the main bar at a part of the plurality of crossing portions that are crossing positions with the plurality of main bars, It has a non-welded part that is not welded to the main bar at the intersection. Therefore, the main reinforcing bar and the shear reinforcing bar are unitized by welding the shear reinforcing bar to the main bar in the welded portion, and the work efficiency in the field can be improved. Each shear reinforcement is welded at at least one intersection. Therefore, when it is unitized, transported to the construction site, during construction, and when subjected to external force after construction, the shear reinforcement is It is possible to contribute to the strength of the beam and the column by arranging the shear reinforcement bars at regular positions without causing any positional deviation with respect to the main bars. In addition, by providing a non-welded part (in other words, not all of the intersecting part as a welded part), it is possible to reduce the trouble of managing the welding when unitizing the main reinforcement and the shear reinforcement. The

  In the reinforcing bar unit according to the present invention, in the cross section orthogonal to the first direction, the plurality of main reinforcing bars are provided along a substantially square shape, and are provided at positions corresponding to at least the four corners of the substantially square shape. In addition, one of the intersections of the plurality of main bars and the shear reinforcement bars, which are surrounded by the shear reinforcement bars and provided at positions corresponding to the four corners of the substantially square box, corresponds to one diagonal of the substantially square box. It is also preferable that a set of intersecting portions is the welded portion, and a set of intersecting portions corresponding to the other diagonals of the substantially rectangular shape is the non-welded portion.

  In this preferred embodiment, the plurality of main bars are provided at positions corresponding to at least the four corners of the substantially quadrilateral, and a set of intersecting portions corresponding to the diagonals of the substantially quadrilateral are used as welds. Therefore, the shear reinforcement bar is welded to the main bar at the two crossing points where the distance is maximum among the plurality of crossing points with the main bar. Therefore, the position shift of the shear reinforcement relative to the main reinforcement can be surely suppressed while providing a non-welded portion to reduce the labor for managing the welding, and an efficient unitization is possible.

  In the reinforcing bar unit according to the present invention, in the cross section orthogonal to the first direction, the plurality of main reinforcing bars are provided on one side of the reinforcing bar unit and on the other side opposite to the one side. The shear reinforcing bar has the welded portion at at least half of the plurality of crossing portions intersecting with the plurality of main reinforcing bars provided on the one side, and the plurality of main reinforcing bars provided on the other side It is also preferable to have the welded portion at at least half of the plurality of intersecting portions intersecting with.

  In this preferable aspect, since at least half of the crossing portions are welded portions on each of the one side and the other side of the reinforcing bar unit, high strength can be ensured as a unit, and at the time of transfer or construction, It is possible to reliably suppress the displacement of the shear reinforcement bars.

  In the reinforcing bar unit according to the present invention, one shear reinforcing bar has the welded portion at the intersection with the one main reinforcing bar, and the non-welded portion at the intersection with the other main reinforcing bar adjacent to the one main reinforcing bar. On the other hand, the other shear reinforcement bars adjacent to the one shear reinforcement bar have the non-welded part at the intersection with the one main reinforcement, while the non-welded part at the intersection with the other main reinforcement. It is also preferable to have

  When the distance between the welded portions is small and the welded portions are concentrated, the thermal effects of the welded portions increase by interacting with each other, and the transformation of the reinforcing steel material becomes remarkable in the welded portion, and the toughness may be greatly reduced. Therefore, in this preferred embodiment, the welded portions are not provided at the intersecting portions adjacent to each other in the first direction, and the welded portions are arranged in a staggered manner. Therefore, the distance between the welded portions is increased to concentrate the welded portions. Can be prevented. Accordingly, a decrease in toughness is suppressed, and high structural performance as a unit can be ensured.

  In the reinforcing bar unit according to the present invention, each of the plurality of shear reinforcing bars is composed of two small-diameter reinforcing bars that are adjacent to each other in a parallel state, and at the intersection of one shear reinforcing bar and one main reinforcing bar, It is also preferable that the small diameter reinforcing bar is welded to the one main reinforcing bar and the other small diameter reinforcing bar is not welded to the one main reinforcing bar.

  The so-called “cover thickness”, which is the shortest distance from the surface of the reinforcing bar to the surface of the concrete that covers it, is generally determined appropriately based on durability and fire resistance. Reinforced concrete beams and reinforced concrete columns used in buildings are required to have a more compact cross-section in order to secure living space and reduce costs by reducing the amount of concrete. It is desirable to do.

  Therefore, in this preferred embodiment, when each of the plurality of shear reinforcing bars is composed of two small-diameter reinforcing bars adjacent in parallel to each other, the strength as a shear reinforcing bar is secured by one reinforcing bar. Compared to the above, a rebar having a smaller diameter can be used. For this reason, the width and height of the cross section can be reduced while maintaining the same concrete cover thickness, and a reinforced concrete beam or a reinforced concrete column using the present reinforcing bar unit can be configured in a compact manner. Furthermore, at the intersection of one shear reinforcement and one main reinforcing bar, one small-diameter rebar is welded to one main reinforcing bar, and the other small-diameter reinforcing bar is not welded to one main reinforcing bar, so the welded part does not concentrate. Further, it is possible to prevent a situation in which the main reinforcing bar and the shear reinforcing bar are excessively heated and the toughness is significantly reduced.

  According to the present invention, it is possible to provide a reinforcing bar unit capable of ensuring high strength and toughness without requiring a great deal of trouble in welding management while improving work efficiency in the field by unitizing the reinforcing bar. Can do.

It is a perspective view which shows the reinforced concrete beam using the reinforcing bar unit which concerns on embodiment of this invention. It is sectional drawing and the side view which show the reinforced concrete beam using the reinforcing bar unit which concerns on embodiment of this invention. It is a schematic diagram which shows the welding location of the reinforcing bar unit which concerns on embodiment of this invention. It is sectional drawing which shows the reinforced concrete pillar using the reinforcing bar unit which concerns on embodiment of this invention.

  Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. In order to facilitate understanding, the same components are denoted by the same reference numerals as much as possible in the drawings, and redundant description is omitted.

  First, with reference to FIG.1 and FIG.2, the outline of the reinforced concrete beam using the reinforcing bar unit which concerns on embodiment of this invention is demonstrated. FIG. 1 is a perspective view showing a reinforced concrete beam using a reinforced unit according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view and a side view showing a reinforced concrete beam using a reinforced unit according to an embodiment of the present invention. It is.

  As shown in FIG. 1, the reinforced concrete beam RCB is composed of a reinforcing bar unit U1 and concrete CO that is densely filled in and around the reinforcing bar unit U1, and has a prismatic shape as a whole. For the sake of simplicity, in FIG. 1 and FIG. 2, only the contour line of concrete CO (that is, the contour line of reinforced concrete beam RCB) is shown by a two-dot chain line.

  The reinforcing bar unit U1 has a plurality of main bars and a plurality of shear reinforcement bars.

  The plurality of main reinforcing bars is composed of upper main reinforcing bars 21 to 26 and lower main reinforcing bars 31 to 36, all of which are steel bars having a substantially circular cross section. The upper main bars 21 to 26 and the lower main bars 31 to 36 extend substantially parallel to the direction of the arrow X, which is the longitudinal direction of the reinforced concrete beam RCB, with a space therebetween.

  As shown in FIG. 2A which is a cross-sectional view orthogonal to the arrow X in FIG. 1, the upper main bars 21 to 26 are provided on the US side closer to the upper end than the central part of the reinforcing bar unit U1, and the lower main bars 31 to 26 are provided. 36 is provided on the LS side near the lower end of the reinforcing bar unit U1. Of these, the upper main bars 21 and 24 and the lower main bars 31 and 34 are provided at positions corresponding to the four corners of a substantially square shape, and the other upper main bars 22, 23, 25 and 26, and the lower main bars 32, 33, Reference numerals 35 and 36 are provided at positions corresponding to the four sides of the substantially rectangular shape.

  The plurality of shear reinforcement bars are composed of shear reinforcement bars 11 to 16. The shear reinforcement bars 11 to 16 are bent steel bars, extend so as to contact and intersect each of the upper main bars 21 to 26 and the lower main bars 31 to 36, and have a substantially rectangular shape in a cross-sectional view. Yes. Further, the shear reinforcement bars 11 to 16 are provided in the direction of the arrow X so as to be arranged at a predetermined interval.

  As shown in FIG. 2B, which is a side view, each of the shear reinforcement bars 11 to 16 has small-diameter rebars 11a to 16a provided on one side in the direction of arrow X, and adjacent to it in the direction of arrow X. It consists of small-diameter rebars 11b to 16b provided on the other side. Each of the small-diameter rebars 11a to 16a and the small-diameter rebars 11b to 16b is a steel bar having a substantially circular shape with a cross-sectional shape of a diameter d.

  For the sake of simplicity, in FIGS. 1 and 2, the upper main bars 21 to 26, the lower main bars 31 to 36, and the shear reinforcement bars 11 to 16 are illustrated as round steels having no irregularities on the surface and a uniform diameter. However, in practice, a deformed reinforcing bar having uneven ribs on the surface may be used in order to increase the adhesion to the concrete filled around them and increase the force against the pulling force.

  Next, welding of the reinforcing bar unit according to the embodiment of the present invention will be described with reference to FIG. Drawing 3 is a mimetic diagram showing the welding part of the reinforcing bar unit concerning the embodiment of the present invention.

  FIG. 3 is a perspective view of the reinforcing bar unit U1 from the same direction as FIG. 1. For convenience of explanation, the upper main bars 21 to 26 and the lower main bars 31 to 36 are represented by thin lines, and the shear reinforcing bars 11 to 16 are thick lines. This is shown in the figure.

  As described above, the upper main bars 21 to 26 and the lower main bars 31 to 36 and the shear reinforcement bars 11 to 16 are in contact with each other, and the shear reinforcement bars 11 to 16 are crossed at the intersections. 26 and lower main bars 31 to 36 are fixed by welding. However, the shear reinforcement bars 11 to 16 are not welded at all the intersections, and consideration is given to prevention of misalignment with respect to the upper main bars 21 to 26 and the lower main bars 31 to 36 and reduction of the work of welding management. Thus, welding is performed only at some intersections. This will be specifically described below.

  In FIG. 3, the welded portions W, which are locations where the shear reinforcement bars 11 to 16 are welded to the upper main bars 21 to 26 and the lower main bars 31 to 36, are indicated by black dots. In the shear reinforcement bars 11 and 16 provided at both ends of the reinforcing bar unit U1 in the X direction, all of the intersections are welds W. However, in the shear reinforcement bars 12 to 15 provided between them, Only the crossing part of the part is set as the welding part W, and the crossing part which is not shown by the other black dots is a non-welded part where the shear reinforcement bars 11 to 16 are not welded.

  Since the shear reinforcement bars 11 to 16 are welded to the upper main bars 21 to 26 and the lower main bars 31 to 36 in the welded portion W, they are unitized, and work efficiency in the field can be improved. In addition, by providing a non-welded part (in other words, not all of the intersecting parts as welded parts), the upper main bars 21 to 26, the lower main bars 31 to 36, and the shear reinforcing bars 11 to 16 are subjected to shear reinforcement. Even when the reinforcement is unitized, the labor for performing the welding management for ensuring toughness is reduced.

  Further, since the shear reinforcement bars 11 to 16 are welded at at least one intersection, the shear reinforcement bars 11 to 16 are also applied when unitized, during construction, and when subjected to external force after construction. The shear reinforcing bars 11 to 16 can be arranged at regular positions to contribute to the strength of the reinforced concrete beam RCB without causing a positional shift with respect to the upper main bars 21 to 26 and the lower main bars 31 to 36.

  All of the shear reinforcement bars 12 to 15 are welded to three main bars, which are half of the six main bars, on the US side closer to the upper end than the central portion of the reinforcing bar unit U1 shown in FIG. The LS side near the lower end is also welded to three main bars, which is half of the six main bars. In this way, at each half of the reinforcing bar unit U1, at least half of the intersecting portions are welded portions W, so that high strength can be ensured as a unit, and at the time of transfer and construction, the main reinforcement It is possible to reliably suppress the displacement of the shear reinforcing bar with respect to.

  Here, paying attention to the shear reinforcing bar 12, of the intersecting portions 221, 224, 231 and 234 where the shear reinforcing bar 12 intersects the upper main bars 21 and 24 and the lower main bars 31 and 34 provided at the four corners of the substantially square shape described above. The intersections 224 and 231 corresponding to one diagonal of the substantially square are the welded portions W, and the intersections 221 and 234 corresponding to the other diagonals are the non-welded portions. The same applies to the shear reinforcement bars 13 to 15. For example, in the shear reinforcement bar 13, the intersecting portions 321 and 334 corresponding to the other diagonals of the substantially rectangular shape are the welded portions W, and in the shear reinforcement bar 14, a pair of The diagonals that are welded by the adjacent shear reinforcement bars are staggered so that the intersecting portions 424 and 431 corresponding to the corners are the welded portions W.

  In this way, by setting the set of intersecting portions corresponding to the diagonals of the substantially quadrilateral as the welded portions W, the shear reinforcing bars 12 to 15 are at the two intersecting portions having the maximum distance among the plurality of intersecting portions. It is welded to the main bar. Therefore, it is possible to reliably suppress the displacement of the shear reinforcing bars 12 to 15 with respect to the main bars while providing a non-welded part and reducing the labor for managing toughness.

  Further, the shear reinforcing bar 12 has a welded portion W at the intersection 233 with the lower main reinforcement 33, and is not welded at the intersection 234 with the lower main reinforcement 34 adjacent to the lower main reinforcement 33. On the other hand, the shear reinforcing bar 13 adjacent to the shear reinforcing bar 12 is not welded at the intersection 333 with the lower main bar 33, but is welded at the intersection 334 with the lower main bar 34, contrary to the shear reinforcing bar 12. W.

  Further, when attention is paid to the shear reinforcing bar 14 adjacent to the shear reinforcing bar 13 and the shear reinforcing bar 15 adjacent to the shear reinforcing bar 14, the shear reinforcing bar 14 has the welded portion W at the intersection 433 with the lower main bar 33. The shear reinforcing bar 15 has a weld W at the intersection 534 with the lower main bar 34.

  In this manner, the lower main bars 33 and 34 are not provided with the welded portions W at the intersections adjacent in the first direction, and the welded portions W are arranged in a staggered manner. For this reason, the distance between the welding parts W can be enlarged and concentration of the welding part W can be prevented. Accordingly, a decrease in toughness is suppressed, and high strength and toughness can be ensured as a unit.

  Moreover, as above-mentioned, the shear reinforcement bars 11-16 are formed by adjoining small diameter reinforcing bars 11a-16a and small diameter reinforcing bars 11b-16b. In welding at the intersections of the shear reinforcing bars 11 to 16, the upper main bars 21 to 26, and the lower main bars 31 to 36, only one of the small diameter reinforcing bars 11a to 16a and the small diameter reinforcing bars 11b to 16b is welded. In detail, taking the shear reinforcement 15 as an example, the intersection 535 is welded only to the small-diameter rebar 15a (not shown in FIG. 3), and the intersection 532 is welded to the small-diameter rebar 15b (FIG. 3). Is welded only to the small-diameter rebar 15a at the intersection 534. That is, among the plurality of welded portions W provided along the shear reinforcement bars 15, in the adjacent welded portions W, one is welded only to the small-diameter rebar 15a, and the other is welded only to the small-diameter rebar 15b. Further, one of the small-diameter rebars 15a and the small-diameter rebars 15b is configured to be alternately welded, and the same applies to other shear reinforcement bars.

  As described above, the cover thickness D (see FIG. 2A), which is the shortest distance between the surface of the reinforcing bar and the surface of the concrete CO covering this, is determined based on durability and fire resistance. Is. When each of the shear reinforcement bars 11 to 16 is composed of two adjacent small-diameter rebars 11a to 16a and small-diameter rebars 11b to 16b, the shear reinforcement bars 11 to 16 are configured by one rebar. Reinforcing bars with a smaller diameter can be used. Therefore, the reinforced concrete beam RCB using the reinforcing bar unit U1 can be made compact while the cover thickness D of the same concrete CO is used. It is possible to increase the living space by suppressing the protrusions of the columns and beams into the room. It also reduces the amount of concrete and contributes to reducing construction costs.

  Furthermore, at the intersection of one shear reinforcement and one main reinforcing bar, one small-diameter rebar is welded to one main reinforcing bar, and the other small-diameter reinforcing bar is not welded to one main reinforcing bar, so the welded part does not concentrate. Further, it is possible to prevent a situation in which the main reinforcing bar and the shear reinforcing bar are excessively heated and the toughness is significantly reduced.

  Next, another embodiment of the present invention will be described with reference to FIG. FIG. 4 is a cross-sectional view showing a reinforced concrete column using a reinforcing bar unit according to an embodiment of the present invention.

  The use of the reinforced unit according to the present invention is not limited to reinforced concrete beams, but can also be applied to reinforced concrete columns, and the effects thereof can be exhibited.

  Specifically, as shown in FIG. 4, a reinforcing bar unit U2 according to the present invention may be provided inside a reinforced concrete column RCP having a substantially square cross section. Similar to the above-described reinforcing bar unit U1, the reinforcing bar unit U2 is also provided with column main bars 41 to 46 and 51 to 56, each extending substantially parallel to the depth direction of the drawing. Similarly to the reinforcing bar unit U1, a plurality of column shear reinforcement bars (only the foremost column shear reinforcement bar 60 is shown in FIG. 4) provided at intervals in the depth direction of the paper are provided. ing.

  If some of the crossing portions of the column reinforcing bars and the column main reinforcing bars 41 to 46 and 51 to 56 are welded parts, the work efficiency in the field can be improved by unitizing the reinforcing bars. While improving, high intensity | strength can be ensured without requiring an effort. Moreover, while arrange | positioning a welding part in the same way as the reinforced concrete beam RCB mentioned above, while suppressing the position shift of each column shear reinforcement with respect to the column main reinforcements 41-46, 51-56, and strength as a column, It is possible to ensure toughness.

  The embodiments of the present invention have been described above with reference to specific examples. However, the present invention is not limited to these specific examples. In other words, those specific examples that have been appropriately modified by those skilled in the art are also included in the scope of the present invention as long as they have the characteristics of the present invention. For example, the elements included in each of the specific examples described above and their arrangement, materials, conditions, shapes, sizes, and the like are not limited to those illustrated, but can be changed as appropriate. Moreover, each element with which each embodiment mentioned above is provided can be combined as long as technically possible, and the combination of these is also included in the scope of the present invention as long as it includes the features of the present invention. It is also possible to apply to SRC (steel reinforced concrete) in which a steel member is arranged in the cross section.

11-16: Shear reinforcement bars 11a-16a, 11b-16b: Small-diameter reinforcing bars 21-26: Upper main bars 31-36: Lower main bars 41-46, 51-56: Main bars for columns 61: Shear reinforcing bars for columns RCB: Reinforced concrete Beam RCP: Reinforced concrete column U1, U2: Reinforcement unit W: Welded part

Claims (6)

A plurality of main bars extending substantially parallel to the first direction at intervals from each other;
A plurality of shear reinforcement bars extending to intersect the plurality of main bars and arranged to be spaced apart from each other in the first direction,
Each of the plurality of shear reinforcing bars has a welded portion that is welded to the main bar at a part of the plurality of crossing portions that are crossing positions with the plurality of main bars, and the other crossing portions. It has a non-weld portion which is not welded to the main reinforcement in,
In the cross section orthogonal to the first direction, the plurality of main bars are provided along a substantially square shape, and are provided at positions corresponding to at least four corners of the substantially square shape, and are surrounded by the shear reinforcement bars. ,
Of the intersecting portions of the plurality of main bars and the shear reinforcing bars provided at positions corresponding to the four corners of the substantially quadrilateral, a set of intersecting portions corresponding to one diagonal of the substantially quadrilateral is the welded portion. The reinforcing bar unit is characterized in that a set of intersecting portions corresponding to other diagonals of the substantially rectangular shape is the non-welded portion . A plurality of main bars extending substantially parallel to the first direction at intervals from each other;
A plurality of shear reinforcement bars extending to intersect the plurality of main bars and arranged to be spaced apart from each other in the first direction,
Each of the plurality of shear reinforcing bars has a welded portion that is welded to the main bar at a part of the plurality of crossing portions that are crossing positions with the plurality of main bars, and the other crossing portions. And having a non-welded portion that is not welded to the main bar,
In the cross section orthogonal to the first direction, the plurality of main bars are provided along a substantially quadrangle, and are surrounded by the shear reinforcement bars, and one side corresponding to one side of the substantially square , and the one side 2 or more on the other side corresponding to the opposite side, and
The shear reinforcing bar has the welded portion at at least half of the plurality of intersecting portions intersecting with the plurality of main reinforcing bars provided on the one side, and intersects with the plurality of main reinforcing bars provided on the other side. rebars unit you comprises said welded portion at least half of the intersections of the plurality of intersections to be. One shear reinforcement has the weld at the intersection with one main reinforcement, and has the non-weld at the intersection with another main reinforcement adjacent to the one main reinforcement,
Other shear reinforcement adjacent to the shear reinforcement of the one, while having the non-welded portion at the intersection between said one of main reinforcement, having a front Ki溶 contact portion at the intersection with the other main reinforcement The reinforcing bar unit according to claim 1 or 2 , characterized by the above-mentioned. Wherein the plurality of each of shear reinforcement s is rebar unit according to any one of claims 1 to 3, characterized in that it consists of two small diameter reinforcing bars adjacent in parallel with each other.   A plurality of main bars extending substantially parallel to the first direction at intervals from each other;
  A plurality of shear reinforcement bars extending to intersect the plurality of main bars and arranged to be spaced apart from each other in the first direction,
  Each of the plurality of shear reinforcing bars has a welded portion that is welded to the main bar at a part of the plurality of crossing portions that are crossing positions with the plurality of main bars, and the other crossing portions. And having a non-welded portion that is not welded to the main bar,
  In the cross section orthogonal to the first direction, the plurality of main bars are surrounded by the shear reinforcement bars,
  Each of the plurality of shear reinforcement bars is composed of two small-diameter rebars adjacent to each other in a parallel state,
  A reinforcing bar unit in which one small-diameter reinforcing bar is welded to the one main reinforcing bar and the other small-diameter reinforcing bar is not welded to the one main reinforcing bar at an intersection of one shear reinforcing bar and one main reinforcing bar.   A reinforced concrete structure comprising the reinforcing bar unit according to any one of claims 1 to 5.

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