JP6792776B2 - Reinforcing bar - Google Patents

Description

The present invention relates to reinforcing bars.

In the connection structure for connecting the floor slabs laid on the superstructure of the bridge, the reinforcing bars of one floor slab and the reinforcing bars of the other floor slab are projected into the space between the two floor slabs, and concrete is created in that space. Is being placed.
As the reinforcing bars used in the reinforced concrete structure such as the above-mentioned connecting structure of the floor slab, there is one in which the fixing force to the concrete is enhanced by expanding the diameter of the head portion from the shaft portion.

In a reinforced concrete structure, the concrete cover thickness from the reinforcing bar to the outer surface of the structure is specified. As described above, in the case of a reinforcing bar whose head diameter is larger than that of the shaft portion, when the cover thickness of the head portion is adjusted to the specified value, the cover thickness of the shaft portion 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 on the plane of the head is subject to the regulation of the cover thickness, so that the cover thickness of the entire reinforcing bar can be suppressed. ..

Utility Model Registration No. 3191370

When the head has a semicircular shape as in the conventional reinforcing bar described above, the amount of deformation of the end of the shaft becomes large when the end of the shaft is forged to form the head. , There is a problem that it is difficult to mold the head.

An object of the present invention is to provide a reinforcing bar that solves the above-mentioned problems, enhances the fixing force to concrete, suppresses the cover thickness of concrete, and facilitates the formation of a head.

In order to solve the above problems, the present invention includes a reinforcing bar, a shaft portion extending in the front-rear direction, and a head portion forged at an end portion of the shaft portion. The width of the upper end portion of the head portion in the left-right direction is formed wider than the diameter of the shaft portion, and the width of the lower end portion of the head portion in the left-right direction is formed narrower than the diameter of the shaft portion. The upper end of the head is formed with an end face that is parallel to the axial direction of the shaft and is inclined so as to be lowered from the central portion in the left-right direction toward the side edge portion . The left and right surfaces of the head are inclined so that the width of the head in the left-right direction becomes narrower from the upper end to the lower end of the head.

In the present invention, the upper and lower, front and rear, and left and right are set for convenience in order to clarify the structure of the reinforcing bar, and do not limit the structure and usage form of the reinforcing bar of the present invention. For example, the upper end of the head may be arranged downward or laterally.

In the present invention, when stress due to bending tensile force and punching shear force acts on the reinforcing bar embedded in concrete, the head engages with the concrete, so that the fixing force to the concrete can be enhanced.
When the reinforcing bar is a deformed reinforcing bar having ribs formed on the outer peripheral surface of the shaft portion, the fixing force to the concrete can be further enhanced.

Further, when arranging the reinforcing bars of the present invention on the reinforced concrete structure, if the end surface of the head is arranged toward the outer surface of the structure, the cover thickness at the end surface of the head is subject to the regulation. Since the cover thickness on the end face of the head is substantially the same as the cover thickness of the shaft portion, the cover thickness of the entire reinforcing bar can be suppressed.
As a result, the cover thickness of the entire reinforcing bar can be suppressed and the weight of the structure can be reduced. When the reinforcing bar of the present invention is applied to a floor slab, the strength of the floor slab can be increased and the weight can be suppressed to the same level as that of the existing floor slab. Furthermore, the minimum plate thickness of the design standard (road bridge specification) can be suppressed.
Further, the end face is inclined so as to be lowered from the central portion in the left-right direction toward the side edge portion. In this configuration, when arranging the reinforcing bars on the reinforced concrete structure, even if the end face of the head is slightly tilted around the axis of the shaft portion, the cover thickness on the end face of the head can be suppressed.

Further, in the reinforcing bar of the present invention, the left side surface and the right side surface are formed on the head, and the head is formed in a substantially triangular shape. In this way, the volume of the head can be reduced as compared with the configuration in which the head is formed in a semicircular shape. Thereby, when the end portion of the shaft portion is forged to form the head portion, the amount of deformation of the end portion of the shaft portion can be suppressed so that the metal fiber (forging streamline) of the head portion is not cut. Therefore, in the reinforcing bar of the present invention, it is easy to form the head.

In the above-mentioned reinforcing bar, it is preferable to make the left side surface and the right side surface flat so that the head can be easily formed.

In the above-mentioned reinforcing bar, when a plate-shaped flange portion is formed on the outer peripheral portion of the base end portion of the head, the head can be reliably engaged with the concrete, so that the reinforcing bar is fixed to the concrete. You can increase your strength.

In the above-mentioned reinforcing bar, when a protrusion 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 concrete can be enhanced.

In the above-mentioned reinforcing bar, a tip surface having the axial direction of the shaft portion as a normal direction is formed at the tip portion of the head portion, and the outer edge portion of the tip surface is the base end surface of the head portion and the shaft portion. It is preferable to dispose of the shaft portion radially outside the corner portion with the outer peripheral surface of the shaft portion.

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

In the above-mentioned reinforcing bar, if the corner portion is formed into a curved surface or a concave portion is formed along the corner portion, the head is formed when the pressing force of the concrete acts from the base end side to the tip end side of the reinforcing bar. Since stress is unlikely to be concentrated on the corners 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 improved.

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

It is a perspective view which showed the reinforcing bar which concerns on 1st Embodiment of this invention. It is a side view which showed the reinforcing bar which concerns on 1st Embodiment of this invention. It is a front view which showed the reinforcing bar which concerns on 1st Embodiment of this invention. It is a side sectional view which showed the connection structure using the reinforcing bar which concerns on 1st Embodiment of this invention. It is a figure which showed the reference example of the reinforcing bar which concerns on 1st Embodiment of this invention, is a front view of the structure which the upper end surface of a head is a plane. It is a figure which showed the modification of the reinforcing bar which concerns on 1st Embodiment of this invention, and is the front view of the structure which the left side surface and the right side surface are curved. It is a perspective view which showed the reinforcing bar which concerns on 2nd Embodiment of this invention. It is a side view which showed the reinforcing bar which concerns on 2nd Embodiment of this invention. It is a front view which showed the reinforcing bar which concerns on 2nd Embodiment of this invention. It is a figure which showed the reference example of the reinforcing bar which concerns on 2nd Embodiment of this invention, is the front view of the structure which the upper end surface of the head is a plane. It is a figure which showed the modification of the reinforcing bar which concerns on 2nd Embodiment of this invention, and is the front view of the structure which the left side surface and the right side surface are curved. It is a 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 components are designated by the same reference numerals, and duplicate description will be omitted.
Further, in the following description, top and bottom, front and back, and left and right are set for convenience in order to clarify the structure 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 1A of the first embodiment is a deformed steel bar. The reinforcing bar 1A includes a shaft portion 10 extending in the front-rear direction and a head portion 20 formed at the tip end portion of the shaft portion 10.

The shaft portion 10 has a grid-like rib 11 formed on the outer peripheral surface of a rod-shaped member having a circular cross section. As described above, the outer peripheral 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 portion 10. The head portion 20 is a portion where the tip portion of the shaft portion 10 is processed by forging. That is, the shaft portion 10 and the head portion 20 are integral members.

The head portion 20 projects radially 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. The bottom of the triangle is arranged at the upper end of the head 20, and the apex of the triangle is arranged at the lower end of the head 20. The head 20 has a symmetrical shape.
As shown in FIGS. 1 and 3, the head portion 20 is formed with a tip end surface 21, a base end surface 22, an upper end surface 23, and a left side surface 24 and a right side surface 25.

As shown in FIG. 3, the width L1 of the upper end portion of the head portion 20 in the left-right direction is formed wider than the diameter D of the shaft portion 10. Further, the width of the lower end portion of the head portion 20 in the left-right direction is formed to be narrower than the diameter D of the shaft portion 10.
The width L1 of the upper end portion of the head portion 20 in the left-right direction is preferably set to be between 1.9 times and 2.5 times the diameter D of the shaft portion 10.

An upper end surface 23 parallel to the axial direction of the shaft portion 10 is formed on the upper end portion of the head portion 20. The upper end surface 23 is slightly inclined so as to be lowered from the central portion in the left-right direction toward the side edge portion. That is, the upper end surface 23 is a convex surface in which the central point in the left-right direction is the highest and becomes lower from the central portion toward 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 center portion in the left-right direction of the upper end surface 23 is preferably set to be between 0.5 times and 0.7 times the diameter of the shaft portion 10. In this way, the head 20 can be kept within the range of the manufacturing error when the head 20 is forged.

The left side surface 24 and the right side surface 25 are planes extending downward from the left and right edges of the upper end surface 23.
The left side surface 24 and the right side surface 25 are inclined so that the width of the head portion 20 in the left-right direction becomes narrower from the upper end portion to the lower end portion. That is, the distance between the left side surface 24 and the right side surface 25 in the left-right direction becomes narrower toward the bottom, 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 tip surface 21 of the head 20 is a substantially triangular surface when viewed from the front, and is divided into an upper tip surface 21a and a lower tip surface 21b.
As shown in FIG. 2, the upper tip surface 21a is a plane whose normal direction is the axial direction of the shaft portion 10. As shown in FIG. 3, the upper tip surface 21a is formed in a trapezoidal shape, and the lower base is formed shorter than the upper base.

The outer edge portion of the upper tip surface 21a is arranged outside 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 in the radial direction of the shaft portion 10.
As shown in FIG. 2, the corner portion 26 is formed on a curved surface. The corner portion 26 is preferably formed on 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 continuously formed on the lower side of the upper tip surface 21a. The lower tip surface 21b is a triangular plane whose bottom is arranged on the upper side. As shown in FIG. 2, the lower tip surface 21b is inclined so as to be displaced rearward as it goes downward.

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

As shown in FIG. 1, a protrusion 27 projects from the upper tip surface 21a of the first embodiment. The protrusion 27 is an elongated portion having a rectangular shaft cross section, and as shown in FIG. 3, extends linearly in the left-right direction through the center point of the shaft portion 10. The amount of protrusion 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 connecting structure for connecting the floor slabs 110 laid on the superstructure 100 of the bridge having the RC floor slab will be described.
Adjacent floor slabs 110 and 110 are placed on the bridge girder at intervals. As a result, 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 bars 1A of the first embodiment are arranged inside the floor slab 110. Further, a portion on the tip end side of the reinforcing bar 1A protrudes horizontally from the end surface of the floor slab 110.
Further, another reinforcing bar 2 is arranged 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 reinforcing bar 1A, the upper end surface 23 of the head 20 is arranged toward the upper surface of the concrete C. Further, in FIG. 4, in the lower reinforcing bar 1A, the upper end surface 23 of the head portion 20 is arranged toward the lower surface of the concrete C.

In this way, after the reinforcing bars 1A are arranged in the space 200, the concrete C is placed in the space 200 and the reinforcing bars 1A are embedded in the 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 acts on the reinforcing bar 1A embedded in concrete C, the head portion 20 and the shaft portion The rib 11 of 10 engages with the concrete C.
Further, 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 enhanced.

In the reinforcing bar 1A of the first embodiment, since the head 20 protrudes to the other reinforcing bar 2, even if the reinforcing bar 1A moves in the concrete C, the head 20 is caught by the other reinforcing bar 2. The displacement 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 26 to the upper tip surface 21a between the base end surface 22 of the head portion 20 and the outer peripheral surface of the shaft portion 10 is the shaft portion 10. It becomes the same as the maximum value of the thickness of the head 20 in the axial direction of. As a result, 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 portion 20 and the outer peripheral surface of the shaft portion 10 is formed on a curved surface (see FIG. 2). Therefore, when the pressing force of the concrete C acts from the base end side to the tip end side of the reinforcing bar 1A, it is difficult for stress to concentrate on the corner portion 26 between the base end surface 22 of the head portion 20 and the outer peripheral surface of the shaft portion 10. .. As a result, the fatigue durability of the connecting portion between the head portion 20 and the shaft portion 10 can be enhanced.

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 toward the outer surface of the concrete C, the cover thickness on the upper end surface 23 of the head 20 is specified. It becomes.
Since the cover thickness T1 on the upper end surface 23 of the head portion 20 has substantially the same size as the cover thickness T2 of the shaft portion 10, the cover thickness of the entire reinforcing bar 1A can be suppressed.
As a result, the cover thickness T1 of the entire reinforcing bar 1A can be suppressed and the weight of the superstructure 100 can be reduced. As described above, when the reinforcing bar 1A of the first embodiment is applied to the floor slab 110, the strength of the floor slab 110 can be increased and the weight can be suppressed to the same level as that of the existing floor slab. Further, 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 portion 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, when the reinforcing bar 1A is arranged on the concrete C, even if the upper end surface 23 of the head 20 is slightly tilted around the axis of the shaft portion 10, 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 portion 20 is formed in a substantially triangular shape. In this way, the volume of the head 20 can be reduced as compared with the configuration in which the head 20 is formed in a semicircular shape. As a result, when the end portion of the shaft portion 10 is forged to form the head portion 20, the amount of deformation of the end portion of the shaft portion 10 is suppressed so that the metal fiber (forging streamline) of the head portion 20 is not cut. be able to.
Further, in the reinforcing bar 1A of the first embodiment, the left side surface 24 and the right side surface 25 of the head portion 20 are formed in a plane.
Therefore, in the reinforcing bar 1A of the first embodiment, the head portion 20 is easily formed by forging at the end portion of the shaft portion 10.

Although the first embodiment of the present invention has been described above, the present invention is not limited to the first embodiment and can be appropriately modified without departing from the spirit of the first embodiment.
In the first embodiment, as shown in FIG. 3, the upper end surface 23 of the head 20 is inclined, but as in the reference example shown in FIG. 5, the entire upper end surface 23 of the head 20 is formed into a flat surface. You may.

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, but as shown in FIG. 6, the left side surface 24 and the right side surface 25 are convex outward. It may be curved so as to have a shape. Further, the left side surface 24 and the right side surface 25 may be curved so as to have a concave shape toward the inside.

In the first embodiment, as shown in FIG. 3, the protrusion 27 is formed on the tip surface 21 of the head 20, but the region on the outer surface of the head 20 where the protrusion 27 is formed is limited. is not. For example, the protrusion 27 may be formed on the left side surface 24 and the right side surface 25 of the head portion 20. Further, it is not necessary to form the protrusion 27 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 portion 10 may be formed by a round bar.

In the first embodiment, as shown in FIG. 4, the connecting structure between the floor slabs 110 and 110 is described, but 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 bars 1A are arranged in the extension direction of the superstructure 100, but the reinforcing bars 1A are arranged in the width direction of the superstructure 100 and the floor slabs arranged side by side in the width direction of the superstructure 100. They may be connected to each other. Further, the reinforcing bar arrangement structure such as the orientation 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 1B of the second embodiment has substantially the same configuration as the reinforcing bar 1A of the first embodiment (see FIG. 1), and the point that the flange portion 28 is formed on the head 20 is a point. It's different.

In the reinforcing bar 1B of the second embodiment, a plate-shaped flange portion 28 is formed on the outer peripheral portion of the base end portion of the head portion 20. The flange portion 28 projects outward from the left side surface 24 and the right side surface 25 of the head portion 20. As shown in FIG. 8, the tip 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 of the flange portion 28 in the protruding direction is preferably set between 0.1 times 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 to be between 0.4 times 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 20, but the flange portion 28 may be formed on the entire circumference of the head 20.

Further, in the second embodiment, as shown in FIGS. 7 and 9, protrusions 27 are formed on the tip surface 21, the left side surface 24, the right side surface 25, and the tip surface of the flange portion 28 of the head portion 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 tip end surface 21 or the base end surface of the head 20. In addition to 22, it can also be received at the flange portion 28. Therefore, in the reinforcing bar 1B of the second embodiment, the fixing force to the concrete can be enhanced.

Further, in the reinforcing bar 1B of the second embodiment, since the flange portion 28 is formed on the head 20 to increase the fixing force to the concrete, the head is compared with the configuration in which the flange portion 28 is not formed on the head 20. The volume of the portion 20 can be reduced. As a result, when the end portion of the shaft portion 10 is forged to form the head portion 20, the amount of deformation of the end portion of the shaft portion 10 can be suppressed.

Although the second embodiment of the present invention has been described above, the present invention is not limited to the second embodiment, and can be appropriately modified as in the first embodiment without departing from the spirit of the first embodiment. ..
For example, as in the reference example shown in FIG. 10, the upper end surface 23 of the head 20 may be formed on 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 have a convex shape toward the outside. The left side surface 24 and the right side surface 25 may be curved so as to have a concave shape toward the inside.

Further, on the outer surface of the head portion 20 of the second embodiment, the region forming the protrusion 27 is not limited. For example, the protrusion 27 may be formed only on the tip surface 21 of the head 20. Further, it is not necessary to form the protrusion 27 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 1C of the third embodiment has substantially the same configuration as the reinforcing bar 1A of the first embodiment (see FIG. 1), and has a configuration of a connecting portion between the head portion 20 and the shaft portion 10. It's different. In the reinforcing bar 1C of the third embodiment, the recess 29 is formed in the connecting portion between the head portion 20 and the shaft portion 10.

In the third embodiment, the recess 29 is formed along the 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 recess 29 is a portion where the base end surface 22 is recessed along the outer peripheral edge of the shaft portion 10. The bottom surface of the recess 29 is formed on a curved surface.

In the third embodiment, when the head portion 20 is forged at the tip end portion of the shaft portion 10, a recess 29 is formed in the base end surface 22.
The method of forming the recess 29 on the base end surface 22 is not limited, but when the recess 29 is formed during forging, the metal fiber (forging streamline) of the head 20 is not cut, so that the head The strength of 20 can be maintained.

Although the third embodiment of the present invention has been described above, the present invention is not limited to the third embodiment, and can be appropriately modified as in the first embodiment without departing from the spirit of the first embodiment. ..
In the third embodiment, as shown in FIG. 12, the recesses 29 are continuously formed in an arc shape along the outer peripheral surface of the shaft portion 10, but the width and depth of the recesses 29 are not limited. Absent. Further, the recess 29 may be formed intermittently.
Further, the concave portion 29 of the third embodiment has a curved bottom surface, but the shape of the concave portion 29 is not limited, and the cross section may be a quadrangle or a triangle. Further, the bottom surface of the recess 29 may be a curved surface in which curved surfaces having a plurality of curvatures are continuous.

1A Reinforcing Bar (First Embodiment)
1B Reinforcing Bar (Second Embodiment)
1C Reinforcing Bar (Third Embodiment)
10 Shaft 11 Rib 20 Head 21 Tip surface 21a Upper tip surface 21b Lower tip surface 22 Base end surface 23 Upper surface 24 Left side 25 Right side 26 Corner 27 Protrusion 28 Flange 29 Recess 100 Superstructure 110 Floor slab C concrete

Claims (8)

The shaft that extends in the front-back direction and
With a forged head at the end of the shaft,
The width of the upper end portion of the head portion in the left-right direction is formed wider than the diameter of the shaft portion.
The width of the lower end portion of the head portion in the left-right direction is formed to be narrower than the diameter of the shaft portion.
At the upper end of the head, an end face that is parallel to the axial direction of the shaft and is inclined so as to decrease from the central portion in the left-right direction toward the side edge is formed.
A reinforcing bar characterized in that the left side surface and the right side surface of the head are inclined so that the width of the head in the left-right direction becomes narrower from the upper end portion to the lower end portion of the head. The reinforcing bar according to claim 1.
A reinforcing bar characterized in that the left side surface and the right side surface are flat surfaces. The reinforcing bar according to claim 1 or 2.
A reinforcing bar characterized in that a plate-shaped flange portion is formed on the outer peripheral portion of the base end portion of the head. The 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. The reinforcing bar according to any one of claims 1 to 4 .
At the tip of the head, a tip surface having the axial direction of the shaft as the normal direction is formed.
The reinforcing bar is characterized in that the outer edge portion of the tip surface is arranged outside the corner portion between the base end surface of the head portion and the outer peripheral surface of the shaft portion in the radial direction of the shaft portion. The reinforcing bar according to claim 5 .
A reinforcing bar characterized in that the corner portion is a curved surface. The shaft that extends in the front-back direction and
With a forged head at the end of the shaft,
The width of the upper end portion of the head portion in the left-right direction is formed wider than the diameter of the shaft portion.
The width of the lower end portion of the head portion in the left-right direction is formed to be narrower than the diameter of the shaft portion.
At the upper end of the head, an end face parallel to the axial direction of the shaft is formed.
The left and right surfaces of the head are inclined so that the width of the head in the left-right direction becomes narrower from the upper end to the lower end of the head.
At the tip of the head, a tip surface having the axial direction of the shaft as the normal direction is formed.
The outer edge portion of the tip surface is arranged outside the corner portion between the base end surface of the head portion and the outer peripheral surface of the shaft portion in the radial direction of the shaft portion.
A reinforcing bar having a recess formed along the corner. The reinforcing bar according to any one of claims 1 to 7 .
A reinforcing bar having ribs formed on the outer peripheral surface of the shaft portion.

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