JP2019052517A - Reinforcement bar - Google Patents

Abstract

To provide a reinforcement bar capable of restraining a cover thickness of concrete while enhancing fixation to concrete and easy to form a head part.SOLUTION: A reinforcement bar 1A comprises a shaft part 10 extending in a longitudinal direction and a head part 20 forged to an end of the shaft part 10. A width of the upper end of the head part 20 in a vertical direction is formed wider than a diameter of the shaft part 10 and a width of the lower end of the head part 20 in a vertical direction is formed narrower than a diameter of the shaft part 10. At the upper end of the head part 20 an upper end surface 23 parallel to the shaft direction of the shaft part 10 is formed. A left side surface 24 and a right side surface 25 of the head part 20 are tilted so that a width of the head part 20 in a vertical direction becomes narrower from the upper end toward the lower end of the head part 20.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a reinforcing bar.

In the connection structure to connect the floor slabs laid on the bridge superstructure, the reinforcing bar of one floor slab and the reinforcing bar of the other floor slab protrude into the space between both floor slabs, and concrete is placed in that space. Has been laid.
As a reinforcing bar used for a reinforced concrete structure such as the above-described connecting structure of floor slabs, there is one in which the fixing force to concrete is increased by expanding the diameter of the head part from the shaft part.

  In reinforced concrete structures, the cover thickness of concrete from the reinforcing bars to the outer surface of the structure is defined. As described above, in the reinforcing bar whose head is expanded in diameter than the shaft, when the cover thickness of the head is adjusted to the specified value, the cover thickness of the shaft becomes larger than the specified value. The weight will increase.

  Therefore, as a conventional reinforcing bar, there is one in which a flat surface is formed on the head and the head is formed in a semicircular shape (see, for example, Patent Document 1). In this configuration, when the plane of the head is arranged toward the outer surface of the structure, the cover thickness in the plane of the head becomes a target for defining the cover thickness, so that the cover thickness of the entire rebar can be suppressed. .

Utility Model Registration No. 3191370

  If the head has a semicircular shape like the above-described conventional reinforcing bars, when the head is forged by shaping the end of the shaft, the amount of deformation at the end of the shaft increases. There is a problem that it is difficult to mold the head.

  It is an object of the present invention to provide a reinforcing bar that solves the above-described problems, increases the fixing force on the concrete, suppresses the cover thickness of the concrete, and facilitates molding of the head.

  In order to solve the above-mentioned problems, the present invention is a reinforcing bar comprising a shaft portion extending in the front-rear direction and a head forged at the end of the shaft portion. The width in the left-right direction of the upper end portion of the head is formed wider than the diameter of the shaft portion, and the width in the left-right direction of the lower end portion of the head portion is formed narrower than the diameter of the shaft portion. An end face parallel to the axial direction of the shaft portion is formed at the upper end portion of the head portion. The left side surface and the right side surface of the head portion are inclined so that the width in the left-right direction of the head portion becomes narrower from the upper end portion to the lower end portion of the head portion.

  In the present invention, the top and bottom, front and rear, and left and right are set for convenience in order to clarify the configuration of the reinforcing bar, and do not limit the structure and usage of the reinforcing bar of the present invention. For example, you may arrange | position the upper end part of a head toward the downward direction or a side.

In the present invention, when a stress due to a bending tensile force and a punching shear force is applied to the reinforcing bar embedded in the concrete, the head engages with the concrete, so that the fixing force to the concrete can be increased.
In addition, when the above-mentioned reinforcing bar is a deformed reinforcing bar in which a rib is formed on the outer peripheral surface of the shaft portion, the fixing force to the concrete can be further increased.

Further, when the reinforcing bar of the present invention is arranged in a reinforced concrete structure, if the end face of the head is arranged facing the outer surface of the structure, the cover thickness at the end face of the head becomes a target to be defined. And since the cover thickness in the end surface of a head becomes a magnitude | size substantially the same as the cover thickness of a axial part, the cover thickness of the whole rebar can be suppressed.
Thereby, the cover thickness of the whole rebar can be suppressed and the structure can be reduced in weight. When the reinforcing bar of the present invention is applied to a floor slab, the weight can be suppressed to be equal to that of an existing floor slab while increasing the strength of the floor slab. Furthermore, it can be suppressed to the minimum floor slab thickness of the design standard (Road Bridge Specification).

  In the reinforcing bar of the present invention, the left side and the right side are formed on the head, and the head is formed in a substantially triangular shape. If it does in this way, the volume of a head can be reduced compared with the structure which formed the head in the semicircle. Thereby, when forging the end part of the shaft part and forming the head part, the deformation amount of the end part of the shaft part can be suppressed so that the metal fibers (forged lines) of the head part are not cut. Therefore, the rebar of the present invention makes it easy to mold the head.

  In the above-described reinforcing bar, it is preferable that the left side surface and the right side surface are flat so that the head is easily formed.

  In the above-described reinforcing bars, when a plate-like flange portion is formed on the outer peripheral portion of the base end portion of the head portion, the head portion can be reliably engaged with the concrete. You can increase your power.

  In the above-described reinforcing bar, when a protruding portion extending linearly on the outer surface of the head is projected, the surface area of the head can be increased, so that the fixing force of the reinforcing bar to the concrete can be increased.

In the above-described reinforcing bar, it is preferable that the end face is inclined so as to be lowered from the central part in the left-right direction toward the side edge part.
In this configuration, when the reinforcing bars are arranged in the reinforced concrete structure, even if the end face of the head is slightly inclined around the axis of the shaft portion, the cover thickness on the end face of the head can be suppressed.

  In the above-described reinforcing bar, a distal end surface whose normal direction is the axial direction of the shaft portion is formed at the distal end portion of the head portion, and an outer edge portion of the distal end surface includes a proximal end surface of the head portion and the shaft portion. It is preferable to arrange | position outside the corner | angular part with the outer peripheral surface of the said axial part in the radial direction.

  In this configuration, the thickness from the corner of the base end surface of the head and the outer peripheral surface of the shaft portion to the tip surface is the same as the maximum value of the head thickness in the axial direction of the shaft portion. The shear strength of the head when a tensile force acts on the reinforcing bar can be increased.

  In the reinforcing bar described above, when the corner is formed into a curved surface or a recess is formed along the corner, the head is pressed when the pressing force of the concrete acts from the proximal end side to the distal end side of the reinforcing bar. Since it is difficult for stress to concentrate on the corner between the base end surface of the portion and the outer peripheral surface of the shaft portion, the fatigue durability of the connecting portion between the head portion and the shaft portion can be increased.

  In the reinforcing bar of the present invention, it is possible to increase the fixing force to the concrete and to suppress the cover thickness of the concrete. Moreover, in the reinforcing bar of the present invention, when the head is formed, the amount of deformation at the end of the shaft portion can be suppressed, so that the head is easily formed.

It is the perspective view which showed the reinforcing bar which concerns on 1st embodiment of this invention. It is the side view which showed the reinforcing bar which concerns on 1st embodiment of this invention. It is the front view which showed the reinforcing bar which concerns on 1st embodiment of this invention. It is the sectional side view which showed the connection structure using the reinforcing bar which concerns on 1st embodiment of this invention. It is the figure which showed the modification of the reinforcing bar which concerns on 1st embodiment of this invention, and is a front view of the structure whose upper end surface of a head is a plane. It is the figure which showed the modification of the reinforcing bar which concerns on 1st embodiment of this invention, and is a front view of the structure where the left side surface and the right side surface are curving. It is the perspective view which showed the reinforcing bar which concerns on 2nd embodiment of this invention. It is the side view which showed the reinforcing bar which concerns on 2nd embodiment of this invention. It is the front view which showed the reinforcing bar which concerns on 2nd embodiment of this invention. It is the figure which showed the modification of the reinforcing bar which concerns on 2nd embodiment of this invention, and is a front view of the structure whose upper end surface of a head is a plane. It is the figure which showed the modification of the reinforcing bar which concerns on 2nd embodiment of this invention, and is a front view of the structure where the left side surface and the right side surface are curving. It is the side view which showed the reinforcing bar which concerns on 3rd embodiment of this invention.

Embodiments of the present invention will be described in detail with reference to the drawings as appropriate.
In the description of each embodiment, the same constituent elements are denoted by the same reference numerals, and redundant descriptions are omitted.
Further, in the following description, “up / down”, “front / rear”, and “left / right” are set for convenience in order to clarify the configuration of the reinforcing bar of the present embodiment, and do not limit the structure and usage of the reinforcing bar of the present invention. .

[First embodiment]
As shown in FIG. 1, the reinforcing bar 1 </ b> A of the first embodiment is a deformed steel bar. The reinforcing bar 1 </ b> A includes a shaft portion 10 extending in the front-rear direction and a head portion 20 formed at the tip portion of the shaft portion 10.

  The shaft portion 10 is formed by forming lattice-like ribs 11 on the outer peripheral surface of a rod-shaped member having a circular cross section. As described above, the outer circumferential surface of the shaft portion 10 is formed with irregularities by the ribs 11.

  A head 20 is formed at the tip of the shaft 10. The head portion 20 is a portion obtained by processing the tip portion of the shaft portion 10 by forging. That is, the shaft portion 10 and the head portion 20 are an integral member.

The head portion 20 protrudes in the radial direction from the shaft portion 10. As shown in FIG. 3, the head 20 is formed in a substantially triangular shape when viewed from the front. A triangular base is disposed at the upper end of the head 20, and a triangular vertex is disposed at the lower end of the head 20. The head 20 has a symmetrical shape.
As shown in FIGS. 1 and 3, the head 20 is formed with a distal end surface 21, a proximal end surface 22, an upper end surface 23, a left side surface 24 and a right side surface 25.

The width L1 in the left-right direction of the upper end portion of the head 20 is formed wider than the diameter D of the shaft portion 10, as shown in FIG. Further, the width in the left-right direction of the lower end portion of the head 20 is formed to be narrower than the diameter D of the shaft portion 10.
The left-right width L1 of the upper end of the head 20 is preferably set between 1.9 and 2.5 times the diameter D of the shaft 10.

  An upper end surface 23 parallel to the axial direction of the shaft portion 10 is formed at the upper end portion of the head portion 20. The upper end surface 23 is slightly inclined so as to fall from the center in the left-right direction toward the side edge. That is, the upper end surface 23 is a convex surface that has the highest center point in the left-right direction and becomes lower from the center to the left and right side edges. The upper end surface 23 is preferably inclined at an angle of 8 degrees or less with respect to the horizontal direction.

  The distance L2 from the axis (axis) of the shaft portion 10 to the central portion in the left-right direction of the upper end surface 23 is preferably set between 0.5 and 0.7 times the diameter of the shaft portion 10. If it does in this way, it can be stored in the range of a manufacturing error when head 20 is forged.

The left side surface 24 and the right side surface 25 are planes extending downward from the left and right edge portions of the upper end surface 23.
The left side surface 24 and the right side surface 25 are inclined so that the width in the left-right direction of the head 20 becomes narrower from the upper end portion toward the lower end portion. In other words, the distance between the left side surface 24 and the right side surface 25 in the left-right direction becomes narrower toward the lower side, and the lower edge portion of the left side surface 24 and the lower edge portion of the right side surface 25 are in contact with each other.
The opening angle R between the left side surface 24 and the right side surface 25 is preferably set between about 55 degrees and 65 degrees.

The front end surface 21 of the head 20 is a substantially triangular surface when viewed from the front, and is divided into an upper front end surface 21a and a lower front end surface 21b.
As shown in FIG. 2, the upper tip surface 21 a is a plane whose normal direction is the axial direction of the shaft portion 10. As shown in FIG. 3, the upper tip surface 21 a is formed in a trapezoidal shape and has a lower bottom shorter than an upper bottom.

The outer edge portion of the upper distal end surface 21 a is disposed on the radially outer side of the shaft portion 10 with respect to the corner portion 26 between the base end surface 22 (see FIG. 2) of the head portion 20 and the outer peripheral surface of the shaft portion 10.
As shown in FIG. 2, the corner 26 is formed in a curved surface. The corner 26 is preferably formed in a curved surface having a radius of 1.0 mm to 3.0 mm.

  As shown in FIG. 3, the lower tip surface 21b is formed continuously below the upper tip surface 21a. The lower front end surface 21b is a triangular plane with the base located on the upper side. As shown in FIG. 2, the lower end surface 21b is inclined so as to be displaced rearward as it goes downward.

  The thickness L3 between the upper end surface 21a and the base end surface 22 is preferably set between 1.0 and 1.2 times the diameter D of the shaft portion 10. In addition, the thickness L4 between the lower edge portion of the lower distal end surface 21b and the base end surface 22 is preferably set between 0.4 and 0.7 times the diameter D of the shaft portion 10.

  As shown in FIG. 1, a protrusion 27 protrudes from the upper front end surface 21 a of the first embodiment. The protrusion 27 is an elongated portion having a rectangular axial cross section, and extends linearly in the left-right direction through the center point of the shaft 10 as shown in FIG. The protrusion amount of the protrusion 27 is preferably set between 0.5 mm and 2.0 mm.

Next, the connection structure of the floor slab 110 using the reinforcing bar 1A of the first embodiment will be described.
In the first embodiment, as shown in FIG. 4, a connection structure for connecting floor slabs 110 laid on a bridge upper work 100 having RC floor slabs will be described.
Adjacent floor slabs 110, 110 are placed on the bridge girder at intervals. Thereby, a space 200 is formed between the adjacent floor slabs 110 and 110.

The floor slab 110 is a precast member made of reinforced concrete, and the reinforcing bar 1 </ b> A of the first embodiment is arranged inside the floor slab 110. Moreover, the site | part of the front end side of the reinforcing bar 1A protrudes from the end surface of the floor slab 110 in the horizontal direction.
Further, another reinforcing bar 2 is disposed between the reinforcing bar 1A protruding from one floor slab 110 and the reinforcing bar 1A protruding from the other floor slab 110.

  In FIG. 4, in the upper rebar 1 </ b> A, the upper end surface 23 of the head 20 is arranged toward the upper surface of the concrete C. In FIG. 4, the upper end surface 23 of the head 20 is arranged toward the lower surface of the concrete C in the lower reinforcing bar 1 </ b> A.

In this way, after reinforcing bar 1A is placed in space 200, concrete C is placed in space 200, and reinforcing bar 1A is embedded in concrete C.
Then, the reinforcing bars 1A of the floor slab 110 are fixed to the concrete C, so that the adjacent floor slabs 110 and 110 are connected via the concrete C.

In the reinforcing bar 1A of the first embodiment as described above, as shown in FIG. 4, when stress due to bending tensile force and punching shear force is applied to the reinforcing bar 1A embedded in the concrete C, the head portion 20 and the shaft portion. Ten ribs 11 engage with the concrete C.
Moreover, in the reinforcing bar 1A of the first embodiment, the surface area of the head 20 is increased by the protrusion 27 provided on the tip surface 21 of the head 20.
Therefore, in the reinforcing bar 1A of the first embodiment, the fixing force to the concrete C can be increased.

  In the reinforcing bar 1A of the first embodiment, since the head 20 protrudes to the other reinforcing bar 2 side, even when the reinforcing bar 1A moves in the concrete C, the head 20 is caught by the other reinforcing bar 2, The shift of the reinforcing bar 1A can be suppressed.

  In the reinforcing bar 1A of the first embodiment, as shown in FIG. 2, the thickness L3 from the corner portion 26 between the base end surface 22 of the head 20 and the outer peripheral surface of the shaft portion 10 to the upper distal end surface 21a is the shaft portion 10. It becomes the same as the maximum value of the thickness of the head 20 in the axial direction. Thereby, as shown in FIG. 4, the shear strength of the head 20 when a tensile force acts on the reinforcing bar 1A from the concrete C can be increased.

  In the reinforcing bar 1A of the first embodiment, the corner portion 26 between the base end surface 22 of the head 20 and the outer peripheral surface of the shaft portion 10 is formed into a curved surface (see FIG. 2). Therefore, when the pressing force of the concrete C acts from the proximal end side to the distal end side of the reinforcing bar 1A, stress is unlikely to concentrate on the corner portion 26 between the proximal end surface 22 of the head 20 and the outer peripheral surface of the shaft portion 10. . Thereby, the fatigue durability of the connection part of the head 20 and the axial part 10 can be improved.

When the reinforcing bar 1A of the first embodiment is arranged on the concrete C, if the upper end surface 23 of the head 20 is arranged facing the outer surface of the concrete C, the cover thickness on the upper end surface 23 of the head 20 is a target to be defined. It becomes.
And since the cover thickness T1 in the upper end surface 23 of the head 20 becomes a magnitude | size substantially the same as the cover thickness T2 of the axial part 10, the cover thickness of the reinforcing bar 1A whole can be suppressed.
Thereby, the superstructure 100 can be reduced in weight while suppressing the cover thickness T1 of the entire rebar 1A. As described above, when the reinforcing bar 1A of the first embodiment is applied to the floor slab 110, the weight of the floor slab 110 can be increased and the weight can be suppressed to be equal to that of the existing floor slab. Furthermore, the floor slab 110 to which the reinforcing bar 1A is applied can be suppressed to the minimum floor slab thickness of the design standard (road bridge specification).

  In the reinforcing bar 1A of the first embodiment, as shown in FIG. 3, the upper end surface 23 of the head 20 is inclined so as to be lowered from the central portion in the left-right direction toward the side edge portion. As a result, as shown in FIG. 4, even when the upper end surface 23 of the head 20 is slightly inclined around the axis of the shaft portion 10 when the reinforcing bar 1A is arranged on the concrete C, the upper end surface of the head 20 The cover thickness T1 at 23 can be suppressed.

In the reinforcing bar 1A of the first embodiment, as shown in FIG. 3, the head 20 is formed in a substantially triangular shape. If it does in this way, the volume of the head 20 can be reduced compared with the structure which formed the head 20 in the semicircle. Thereby, when forging the edge part of the axial part 10 and shape | molding the head part 20, the deformation amount of the edge part of the axial part 10 is suppressed so that the metal fiber (forged streamline) of the head part 20 may not be cut | disconnected. be able to.
Furthermore, in the reinforcing bar 1A of the first embodiment, the left side surface 24 and the right side surface 25 of the head 20 are formed in a plane.
Therefore, in the reinforcing bar 1A of the first embodiment, it is easy to form the head 20 at the end of the shaft portion 10 by forging.

As mentioned above, although 1st embodiment of this invention was described, this invention is not limited to 1st embodiment, In the range which does not deviate from the meaning, it can change suitably.
In the first embodiment, the upper end surface 23 of the head 20 is inclined as shown in FIG. 3, but the entire upper end surface 23 of the head 20 may be formed as a flat surface as shown in FIG. .

  In the first embodiment, as shown in FIG. 3, the left side surface 24 and the right side surface 25 of the head 20 are flat surfaces, but as shown in FIG. 6, the left side surface 24 and the right side surface 25 protrude outward. You may make it curve so that it may become a shape. Further, the left side surface 24 and the right side surface 25 may be curved so as to be concave toward the inside.

  In the first embodiment, as shown in FIG. 3, the protrusion 27 is formed on the distal end surface 21 of the head 20, but the region where the protrusion 27 is formed on the outer surface of the head 20 is limited. is not. For example, the protrusions 27 may be formed on the left side surface 24 and the right side surface 25 of the head 20. Further, the protrusion 27 may not be formed on the outer surface of the head 20.

  In the first embodiment, as shown in FIG. 1, the rib 11 is formed on the outer peripheral surface of the shaft portion 10, but the rib 11 may not be formed on the outer peripheral surface of the shaft portion 10. That is, the shaft part 10 may be formed by a round bar.

In the first embodiment, as shown in FIG. 4, the connection structure between the floor slabs 110 and 110 is described. However, the structure to which the reinforcing bar of the present invention can be applied is not limited, and various types of reinforced concrete are used. It can be applied to structures.
In the first embodiment, the reinforcing bar 1A is arranged in the extending direction of the superstructure 100, but the reinforcing bar 1A is arranged in the width direction of the superstructure 100, and the floor slab arranged in parallel in the width direction of the superstructure 100. You may connect each other. Furthermore, the arrangement of the reinforcing bars such as the direction and position of the reinforcing bar 1A is not limited.

[Second Embodiment]
Next, the reinforcing bar 1B of the second embodiment will be described.
As shown in FIG. 7, the reinforcing bar 1 </ b> B of the second embodiment has substantially the same configuration as that of the reinforcing bar 1 </ b> A (see FIG. 1) of the first embodiment, and the flange portion 28 is formed on the head 20. Is different.

  In the reinforcing bar 1B of the second embodiment, a plate-like flange portion 28 is formed on the outer peripheral portion of the base end portion of the head 20. The flange portion 28 protrudes outward from the left side surface 24 and the right side surface 25 of the head 20. As shown in FIG. 8, the front end surface and the base end surface of the flange portion 28 are planes whose normal direction is the axial direction of the shaft portion 10.

The width in the protruding direction of the flange portion 28 is preferably set between 0.1 and 0.5 times the diameter of the shaft portion 10. Further, as shown in FIG. 8, the thickness L5 of the flange portion 28 in the axial direction of the shaft portion 10 is preferably set between 0.4 and 0.7 times the diameter of the shaft portion 10.
In the second embodiment, the flange portion 28 is formed on the left side surface 24 and the right side surface 25 of the head portion 20, but the flange portion 28 may be formed on the entire circumference of the head portion 20.

  Further, in the second embodiment, as shown in FIGS. 7 and 9, protrusions 27 are formed on the distal end surface 21, the left side surface 24, the right side surface 25, and the distal end surface of the flange portion 28 of the head 20.

  In the reinforcing bar 1B of the second embodiment as described above, as shown in FIG. 8, when the pressing force of the concrete acts in the axial direction of the reinforcing bar 1B, the pressing force is applied to the distal end surface 21 or the proximal end surface of the head 20. In addition to 22, it can also be received by the flange portion 28. Therefore, in the reinforcing bar 1B of the second embodiment, it is possible to increase the fixing force to concrete.

  Further, in the reinforcing bar 1B of the second embodiment, since the fixing force to the concrete is enhanced by forming the flange portion 28 in the head portion 20, compared to the configuration in which the flange portion 28 is not formed in the head portion 20. The volume of the part 20 can be reduced. Thereby, when forging the edge part of the axial part 10 and shape | molding the head part 20, the deformation amount of the edge part of the axial part 10 can be suppressed.

As mentioned above, although 2nd embodiment of this invention was described, this invention is not limited to 2nd embodiment, It can change suitably in the range which does not deviate from the meaning similarly to 1st embodiment. .
For example, as shown in FIG. 10, the upper end surface 23 of the head 20 may be formed as a flat surface. Further, as shown in FIG. 11, the left side surface 24 and the right side surface 25 may be curved so as to be convex toward the outside. Note that the left side surface 24 and the right side surface 25 may be curved so as to be concave toward the inside.

  Moreover, the area | region which forms the projection part 27 in the outer surface of the head 20 of 2nd embodiment is not limited. For example, the protrusion 27 may be formed only on the tip surface 21 of the head 20. Further, the protrusion 27 may not be formed on the outer surface of the head 20.

[Third embodiment]
Next, the reinforcing bar 1C of the third embodiment will be described.
As shown in FIG. 12, the reinforcing bar 1 </ b> C of the third embodiment has substantially the same configuration as the reinforcing bar 1 </ b> A (see FIG. 1) of the first embodiment, and the configuration of the connecting portion between the head 20 and the shaft portion 10. Is different. In the reinforcing bar 1 </ b> C of the third embodiment, a concave portion 29 is formed in the connecting portion between the head portion 20 and the shaft portion 10.

In the third embodiment, a concave portion 29 is formed along a corner portion 26 between the base end surface 22 of the head portion 20 and the outer peripheral surface of the shaft portion 10.
The concave portion 29 is a portion in which the base end surface 22 is recessed along the outer peripheral edge portion of the shaft portion 10. The bottom surface of the recess 29 is formed in a curved surface.

In the third embodiment, when the head portion 20 is forged at the distal end portion of the shaft portion 10, the concave portion 29 is formed on the proximal end surface 22.
In addition, although the method of forming the recessed part 29 in the base end surface 22 is not limited, Since the metal fiber (forged streamline) of the head 20 is not cut when the recessed part 29 is formed at the time of forging, the head The strength of 20 can be maintained.

As mentioned above, although 3rd embodiment of this invention was described, this invention is not limited to 3rd embodiment, It can change suitably in the range which does not deviate from the meaning similarly to 1st embodiment. .
In the third embodiment, as shown in FIG. 12, the concave portion 29 is continuously formed in an arc shape along the outer peripheral surface of the shaft portion 10, but the width and depth of the concave portion 29 are not limited. Absent. Moreover, you may form the recessed part 29 intermittently.
Moreover, although the bottom surface of the concave portion 29 of the third embodiment is formed in a curved surface, the shape of the concave portion 29 is not limited, and the cross section may be a square or a triangle. The bottom surface of the recess 29 may be a curved surface in which curved surfaces having a plurality of curvatures are continuous.

1A rebar (first embodiment)
1B Reinforcing bar (second embodiment)
1C Reinforcing bar (third embodiment)
DESCRIPTION OF SYMBOLS 10 Shaft part 11 Rib 20 Head 21 Front end surface 21a Upper front end surface 21b Lower front end surface 22 Base end surface 23 Upper end surface 24 Left side surface 25 Right side surface 26 Corner portion 27 Protrusion portion 28 Flange portion 29 Recess portion 100 Superstructure 110 Floor slab concrete

Claims (9)

A shaft portion extending in the front-rear direction;
A head forged at the end of the shaft portion,
The width in the left-right direction of the upper end portion of the head is formed wider than the diameter of the shaft portion,
The width in the left-right direction of the lower end portion of the head is formed narrower than the diameter of the shaft portion,
An end face parallel to the axial direction of the shaft portion is formed at the upper end portion of the head portion,
The left and right sides of the head are inclined such that the width in the left-right direction of the head becomes narrower from the upper end to the lower end of the head. The reinforcing bar according to claim 1,
The reinforcing bar, wherein the left side surface and the right side surface are flat surfaces. Reinforcing bar according to claim 1 or claim 2,
A reinforcing bar having a plate-like flange portion formed on an outer peripheral portion of a base end portion of the head portion. Reinforcing bar according to any one of claims 1 to 3,
A reinforcing bar characterized in that a linearly extending protrusion protrudes from the outer surface of the head. Reinforcing bar according to any one of claims 1 to 4,
The said end surface is inclined so that it may fall as it goes to a side edge part from the center part of the left-right direction, The reinforcing bar characterized by the above-mentioned. The reinforcing bar according to any one of claims 1 to 5,
The tip of the head is formed with a tip surface whose normal direction is the axial direction of the shaft,
An outer edge portion of the distal end surface is disposed on a radially outer side of the shaft portion with respect to a corner portion between a base end surface of the head portion and an outer peripheral surface of the shaft portion. The reinforcing bar according to claim 6,
The reinforcing bar characterized in that the corner is a curved surface. The reinforcing bar according to claim 6,
A rebar having a recess formed along the corner. Reinforcing bar according to any one of claims 1 to 8,
A reinforcing bar, wherein a rib is formed on an outer peripheral surface of the shaft portion.

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