CN114144558A

CN114144558A - Steel bar joint, steel bar assembly and prefabricated reinforced concrete body

Info

Publication number: CN114144558A
Application number: CN201980098695.2A
Authority: CN
Inventors: 福田章; 胁山广三; 平井敬二
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-07-24
Filing date: 2019-07-24
Publication date: 2022-03-04
Also published as: US20220127838A1; WO2021014616A1; KR20220012950A

Abstract

A joint (B) for reinforcing bars in which ends of a pair of reinforcing bars (1, 1) opposing in a length direction are connected to each other, comprising: a cylindrical body (10), wherein an internal thread part (14) is formed on the inner surface of the cylindrical body (10); joint members (11, 11), the joint members (11, 11) having a joint male screw thread portion (13) at one end; and a connecting member (19) for connecting the pair of joint members (11, 11) to each other so as to be displaceable in the longitudinal direction and in the direction orthogonal thereto, wherein a reinforcing bar male screw portion (15) formed at one end of one reinforcing bar (1) is screwed to one end of the tubular body (10), and a joint male screw portion (13) at one end of the joint member (11) is screwed to the other end.

Description

Steel bar joint, steel bar assembly and prefabricated reinforced concrete body

Technical Field

The present invention relates to a steel bar coupler and a steel bar assembly which are most suitable for a prefabrication process used in the construction of a reinforced concrete structure such as a beam or a column, and a prefabricated reinforced concrete body.

Background

As is well known, the steel bar joints in reinforced concrete structures such as beams and columns are roughly classified into the following four types. Namely lap joints, gas pressure joints, welded joints and mechanical joints. In particular, a mechanical joint is known as a technique for integrating a reinforcing bar by covering a coupler on an end portion of the reinforcing bar and by engaging a joint portion of the reinforcing bar with the coupler or by screwing. As advantages of the mechanical joint, there are mentioned that the reinforcing bars do not shrink during construction, that all joints can be realized at the end of the member, that the operator does not need to be qualified in particular, and that the mechanical joint is not affected by weather or the like.

In addition to the four types of reinforcing bar joints, a method of joining reinforcing bars to each other using an expensive grouting material (mortar, grout, synthetic resin, or the like) is also employed (for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: JP 2008-63730 publication

Disclosure of Invention

Problems to be solved by the invention

However, in the case of this grout joint, it is difficult to secure the positional accuracy as the set of reinforcing bars, and it takes a considerable time until the grout cures to reach a predetermined strength after the injection of the grout. Therefore, the grouting material cannot enter the next process before it is cured, which has a great influence on the cost and the construction period.

The present invention aims to provide a steel bar coupler and a steel bar assembly which can be effectively applied to a prefabrication process used for the construction of reinforced concrete structures such as beams and columns without causing high cost and delay of construction period, and a prefabricated reinforced concrete body.

Means for solving the problems

In order to achieve the above object, a reinforcement bar coupler according to the present invention is a reinforcement bar coupler in which ends of a pair of reinforcement bars opposing in a longitudinal direction are coupled to each other, the reinforcement bar coupler including: a cylindrical body having an internal thread portion formed on an inner surface thereof; a joint member having a joint male screw portion at one end; and a connecting member for connecting the pair of joint members to each other so as to be displaceable in the longitudinal direction and in the direction orthogonal thereto, wherein a reinforcing bar male screw portion formed at an end portion of one reinforcing bar is screwed to one end portion of the cylindrical body, and the joint male screw portion at one end portion of the joint member is screwed to the other end portion.

According to this configuration, when the pair of reinforcing bar joints are joined to each other in the tubular body, the pair of reinforcing bar joints can be joined only by screwing without using a grouting material such as mortar, which is expensive and takes several days for curing. Further, the connecting member connecting the pair of joint members facing each other is connected so that the pair of joint members are displaceable in the longitudinal direction and the direction orthogonal thereto. Therefore, even if there is a slight eccentricity between the pair of joint members, that is, a slight eccentricity or a positional deviation in the longitudinal direction between the pair of reinforcing bars, the pair of joint members, that is, the pair of reinforcing bars are connected to each other by absorbing the deviation, and it is easy to ensure the positional accuracy as the reinforcing bar group. Thus, even if a certain allowable range exists for the connection between the pair of reinforcing bars, the construction period can be shortened.

In the present invention, the joint member may have a body portion and the male screw portion, and the connection member and the joint member may be detachably connected by a fastening member in a state where the body portions of the pair of joint members face each other in the longitudinal direction. According to this configuration, the reinforcement can be assembled quickly and easily not only in a factory but also in a construction site.

In the present invention, the body portion of the joint member may be interposed between the pair of connection members. According to this configuration, since the body portion of the joint member is firmly held by the pair of connection members in a sandwich structure, the reliability of the joint between the pair of reinforcing bars is also improved.

In the bar assembly according to the present invention, the plurality of bars are arranged in parallel and coupled by the ribs, the cylindrical body having the internal thread portion on the inner surface is screwed to the external thread portion of the iron bar formed in the bar, the external thread portion of the bar enters the axially inner portion of the internal thread portion, and the axially outer portion of the internal thread portion is exposed to the outside of the bar assembly. According to this configuration, since the internal thread portion of the cylindrical body is exposed to the end portion of the reinforcing bar, the coupling member can be easily coupled to the reinforcing bar by screwing the coupling member to the exposed internal thread portion. Therefore, the work of connecting the reinforcing bars to each other by the reinforcing bar joint can be made efficient.

In the precast reinforced concrete body according to the present invention, the tubular body and the reinforcing bars in the reinforcing bar joint are embedded in concrete, and the female screw portion of the tubular body is exposed from an end surface of the concrete. According to this structure, when prefabricated reinforced concrete bodies that can be beams or columns in a reinforced concrete structure are produced in a factory and joined at a construction site, the adjacent prefabricated reinforced concrete bodies can be easily joined by the reinforcing bar joints using the female screw portions of the outer end surfaces of the tubular bodies that are exposed from the end surfaces of the concrete. Therefore, workability at a construction site is remarkably improved.

Any combination of at least two structures disclosed in the claims and/or the description and/or the drawings is encompassed by the present invention. In particular, any combination of two or more of the individual claims in the claims is also encompassed by the present invention.

Drawings

The invention will be more clearly understood from the following description of preferred embodiments with reference to the accompanying drawings. However, the embodiments and the drawings are for illustrative and descriptive purposes only and should not be construed to limit the scope of the present invention. The scope of the invention is determined by the claims. In the drawings, like reference characters designate like or corresponding parts throughout the several views.

Fig. 1 is a front view of a reinforcing bar coupler and a reinforcing bar assembly according to embodiment 1 of the present invention;

fig. 2 is an exploded perspective view of a reinforcing bar coupler screwed to an external thread portion of a reinforcing bar at an end portion of the reinforcing bar of the embodiment;

fig. 3 is an enlarged perspective view of a coupling member of the reinforcing bar coupling;

fig. 4 is an enlarged cross-sectional view showing another installation structure of the end surface of the male screw portion of the reinforcing bar and the formwork;

FIG. 5 is a side view of the rebar junction;

fig. 6 is a front view of the reinforcing bar coupler;

fig. 7 is a front view showing a reinforcing bar coupler in a state where a coupling member is removed in a case where eccentric reinforcing bars are coupled to each other.

Fig. 8 is a side view of the reinforcing bar coupler according to embodiment 2.

Detailed Description

Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. Fig. 1 is a front view showing a state in which a reinforcing bar assembly according to embodiment 1 of the present invention is attached to a formwork.

< Structure of reinforcing bar Assembly >

Fig. 1 shows a reinforcement assembly a that can be one of a beam or a column on the right side and another reinforcement assembly a that can be the other of the beam or the column on the left side. In this example, a case where the reinforcing bar assembly a can become a beam is shown. The left and right reinforcement assemblies A, A are the same assemblies using the same number of main reinforcements (reinforcements) 1 and the same or different number of ribs 2.

In fig. 1, a plurality of reinforcing bars 1 as main bars of a reinforcing bar assembly a are arranged apart in the vertical direction of fig. 1 and the inside-outside direction of the drawing sheet, and extend in the horizontal direction (in this example, the horizontal direction) in parallel with each other. A plurality of ribs 2 as shear ribs are wound around these reinforcing bars 1. The reinforcing bar 1 is a deformed reinforcing bar having a projection formed on the outer periphery thereof, the projection including a rib extending in the longitudinal direction and nodes extending in the circumferential direction at regular intervals, but may be a normal round bar.

The end of the reinforcing bar 1 is formed with an external thread portion 15 by roll forming, for example. The male screw portion 15 may be formed separately from the reinforcing bar 1 and joined to the end face of the reinforcing bar 1 by welding. The cylindrical body 10 having an internal thread portion formed on an inner surface thereof is screwed to the external thread portion 15. As described later, the reinforcing bar assembly a is attached to the formwork 7 by screwing the attachment screw body 6 inserted from the outside of the formwork 7 into the cylindrical body 10. The reinforcing bar assembly a located on the left side is also the same structure.

Each of the steel bar assemblies a is prepared by placing ready-mixed concrete in a formwork 7 in a state where the formwork 7 is installed in a factory, and then producing a precast reinforced concrete body P (hereinafter, simply referred to as PC concrete body P) such as a beam or a column. However, the steel bar assembly a with the formwork 7 may be transported to a construction site, and the ready-mixed concrete may be poured into the formwork 7 at the construction site. The reinforcing bars 1, the ribs 2, the tubular body 10, and the formwork 7 may be transported to a construction site, respectively, and after the reinforcing bar assembly a with the formwork 7 is produced at the construction site, the ready-mixed concrete may be poured into the formwork 7.

Next, the screw body 6 is removed, the formwork 7 is removed, and the right and left reinforcing bars 1, 1 of the PC concrete body P are connected to each other by the reinforcing bar joint B. In this example, the PC concrete P is assumed to be a beam, but when the PC concrete P is a column, the reinforcing bars 1, 1 of a pair of upper and lower PC concrete P are connected to each other.

< Structure of reinforcing bar Joint >

The reinforcing bar coupler B is explained with reference to fig. 2. As shown in the exploded perspective view of the figure, the reinforcing bar coupler B includes a cylindrical body 10 serving as a coupler having a female screw portion 14 formed on the inner surface; a joint member 11 having a joint male screw portion 13 at one end; and a connecting member 19 for connecting the pair of

joint members

11, 11 to each other.

The connecting members 19 are a pair of upper and lower members, and hold the joint member 11 in a sandwich structure, and hold the joint member 11 so as to be displaceable in the longitudinal direction (axial direction) X and the direction Y orthogonal thereto. The joint member 11 and the reinforcing bar 1 share the same longitudinal direction X, and a direction orthogonal to the longitudinal direction X and parallel to the main surface of the body 12 of the joint member 11, i.e., orthogonal to the through hole 17 is denoted by Y, and a direction orthogonal to the two directions X, Y is denoted by Z. As described above, the cylindrical body 10 is buried in the concrete body P.

Here, the cylindrical body 10 has a hexagonal outer shape in cross section, and an internal thread portion 14 to be screwed with an exposed external thread portion 15 of the end portion of the bar 1 is formed on the inner surface thereof. The outer shape of the cylindrical body 10 may be circular or polygonal in cross section. The reinforcing bar external thread portion 15 is screwed only to an axially inner portion which is a part of the internal thread portion 14 of the cylindrical body 10. As shown in fig. 3, the joint member 11 has a flat body 12 and an external thread 13 screwed into an internal thread 14 of the tubular body 10 at the distal end thereof.

Three through holes 17 are formed in the main body 12 at predetermined intervals (for example, 60 mm). The number of the through holes 17 is 3 in this example, but may be 2, or may be 4 or more. The through-hole 17 is a loose-fitting hole (oversized hole) having an inner diameter several mm larger than the outer diameter of a high-strength bolt or an ultra-high-strength bolt (hereinafter, simply referred to as "bolt") 25 described later, and a friction adjusting portion 17a formed of an annular protrusion or a chamfer is formed at the edge portion of both ends thereof. As a result, when the bolt 25 is tightened with a large force, the projection is crushed, or a part of the connecting member 19 enters the chamfered recess, so that the frictional force increases, and the force transmission efficiency improves.

The tubular body 10 and the joint member 11 in fig. 2 are arranged so that members having the same structure face each other in the longitudinal direction (in this case, the horizontal direction is assumed because reinforcing bars for beams are assumed), and the male screw portion 13 of each joint member 11 is screwed into the female screw portion 14 of the corresponding tubular body 10. When the connection of the PC concrete bodies P, P is obstructed, the joint member 11 may be attached to the cylindrical body 10 of the PC concrete body P later. A slight gap S (about 70 mm) exists between the

joint members

11, 11. By rotating the joint member 11 to increase or decrease the amount of screwing into the cylindrical body 10, the size of the gap S is changed, thereby absorbing an error in the dimension of separation between the reinforcing bars 1, 1.

Fig. 4 is an enlarged view showing a structure for installing the reinforcing bars 1 in the formwork 7 of fig. 1. As shown in the drawing, a screw hole 20 is formed in advance in an outer end surface of the male screw body 16 for a die plate. The template male screw 16 is attached to the template 7 via the attachment screw 6. A cylindrical body 10 is screwed to the male screw 6 for a formwork, and a male screw 15 of the reinforcing bar 1 is screwed to a female screw 14 on the inner surface of the cylindrical body 10. Further, it is fixed by a lock nut 30 as necessary.

In this state, as described above, the ready-mixed concrete is poured into the formwork 7 to the pouring surface 35, and the formwork 7 is removed to obtain the PC concrete body P. When connecting the reinforcing bars 1, the male screw 16 for the formwork is removed by a tool, and the female screw 14 on the inner surface of the cylindrical body 10 is exposed to the outside from the end surface of the PC concrete body P. The male screw portion 13 of the joint member 11 in fig. 2 is screwed into the exposed female screw portion 14. On the outside of the formwork 7, a steel bracket 9 for positioning a reinforcing bar is detachably attached by an attaching screw body 6.

As a modification for attaching the reinforcing bar 1 to the form 7, the form screw body 16 may be omitted, and the reinforcing bar 1 with the tubular body 10 may be attached to the form 7 by lengthening the attachment screw body 6 and screwing it into the screw hole 20A provided in the end surface of the reinforcing bar 1 as shown by the two-dot chain line. In this modification, when the formwork 7 is removed, the female screw portion 14 of the tubular body 10 is exposed to the outside from the end face of the PC concrete body P.

As shown in fig. 5, the

body portions

12 and 12 of the

joint members

11 and 11 are held in contact with the pair of

connection members

19 and 19 from the front and back sides, and are held in a sandwich structure. The connecting member 19 is formed of a flat plate, and six connecting holes 27 are provided at positions corresponding to the through holes 17 of the joint member 11. A bolt 25 as an example of a fastening member is inserted through the coupling hole 27 of one of the coupling members 19. The bolt 25 passes through the through hole 17 of the joint member 11 and its tip portion protrudes from the coupling hole 27 of the opposite connection member 19. The tip end of the fastening member (bolt) 25 is fastened by a nut 30. Therefore, in this example, the fastening member is constituted by the bolt 25 and the nut 30.

The coupling hole 27 is also an oversized hole having an inner diameter several mm larger than the outer diameter of the fastening member 25. According to the design and implementation guidelines for bolt joints, oversized holes having inner diameters of up to +6mm and up to +8mm are allowed for bolts having diameters of 24mm and 27mm, respectively. In this way, a larger gap exists between the

oversized holes

17, 27 and the bolt 25 than in the case of normal screwing, and the

joint members

11, 11 can be connected to each other by the connecting member 19 so as to be displaceable by the gap in the longitudinal direction X and the orthogonal direction Y. Thus, as shown in figure 6, adjacent PC concrete bodies P, P are connected to each other by rebar junctions B.

< connecting work of reinforcing bar joints >

When two reinforcing bars 1, 1 to be reinforcing bars of a beam or column are connected by the reinforcing bar joint B, first, the joint male screw portion 13 of the joint member 11 is screwed into the female screw portion 14 of the tubular body 10 of fig. 2. At this time, the lock nut 31 and the washer 32 shown in fig. 5 are mounted at both ends of the cylindrical body 10 as necessary. Thus, in a state where the reinforcing-bar external thread portion 15 enters the axially inner portion of the internal thread portion 14 of the tubular body 10, the joint external thread portion 13 is screwed into the axially outer portion as the other portion.

In this state, as described above, the

joint members

11 and 11 are sandwiched and held by the plate-shaped connecting

members

19 and 19. Further, 6 bolts 25 are inserted through the coupling holes 27 of the coupling member 19 and the coupling holes 17 of the coupling member 11, and nuts 30 are screwed into the bolt top front portions via washers 32 as necessary to be fastened. The gaps between the PC concrete bodies P, P thus joined are filled in place by casting concrete. Therefore, the reinforcing bar coupler B is buried in concrete without being exposed to the outside.

< action, Effect >

The reinforcing bar coupler B of the present invention configured as described above can be connected by screwing only without using a grouting material, such as mortar, which is expensive and requires a time of several days for curing, and thus can reduce construction costs and shorten the construction period. The pair of joint members 11 facing each other in fig. 2 has a body portion 12 and a male screw portion 13, and the connection member 19 and the joint member 11 are detachably connected to each other by fastening

members

25 and 30 in a state where the

body portions

12 and 12 of the pair of joint members 11 face each other in the longitudinal direction. This simplifies the coupling structure. Therefore, not only the assembling of the reinforcing bars in the factory but also the assembling of the reinforcing bars in the construction site can be performed quickly and easily.

In fig. 6, the

joint members

11, 11 are concentric with each other, but as shown in fig. 7, an eccentricity C1 may exist between the axial center X1 in the longitudinal direction of one joint member 11 and the axial center X2 of the other joint member 11, or a positional displacement in the axial direction, that is, a variation in the size of the gap S may exist. In this case, too, the through hole 17 of the joint member 11 and the coupling hole 27 of the coupling member 19 are too large. Accordingly, the misalignment of the reinforcing bars 1, 1 is absorbed and the connection is smooth.

In order to smoothly perform the fastening operation of the bolt 25, the body 12 of the joint member 11 may be oriented in a direction in which the fastening operation is good. In this case, eccentricity may occur in the Z direction shown in fig. 5, and a gap may occur between the body 12 and the connection member 19. Although the auxiliary plate may be inserted into the gap, even if the auxiliary plate is not present, since the gap S in the longitudinal direction X exists between the

joint members

11 and 11, the joint member 11 and the connection member 19 are deformed in an inclined manner by strongly tightening the bolt 25, and the gap in the Z direction between the joint member 11 and the connection member 19 can be eliminated.

Further, since the body portion 12 of the joint member 11 is interposed between the pair of

connection members

19, 19 shown in fig. 5, the body portion 12 of the joint member 11 is firmly held by the pair of

connection members

19, 19 in a sandwich structure, and therefore, the reliability of the joint between the pair of reinforcing bars 1, 1 is also improved.

In the reinforcing bar assembly a of the present invention, a plurality of reinforcing bars 1 are arranged in parallel and coupled by the ribs 2. In such a bar assembly a, the tubular body 10 having the internal thread portion 14 on the inner surface thereof is screwed with the external thread portion 15 formed on the bar 1, the external thread portion 15 enters the axially inner portion of the internal thread portion 14, and the axially outer portion of the internal thread portion 14 is exposed to the outside of the bar assembly a. Therefore, the joint member 11 can be easily coupled to the reinforcing bar 1 by screwing the joint male screw portion 13 of the joint member 11 to the exposed female screw portion 14. As a result, the operation of connecting the reinforcing bars 1, 1 to each other by the reinforcing bar joint B can be made efficient. This improves work efficiency both when a reinforced concrete structure such as a beam or a column is mass-produced in a factory and when concrete is cast in a construction site.

Next, a reinforcing bar joint according to embodiment 2 will be described with reference to fig. 8. The basic structure of embodiment 2 is the same as that of embodiment 1 shown in fig. 5, and differs only in that the cylindrical body 10 of the reinforcing bar coupler B is not embedded in the PC concrete body P. The external thread part 15 of the end of the reinforcing bar 1 protrudes from the PC concrete body P, and the cylindrical body 10 is screwed to the protruding external thread part 15 at the construction site. The connection structure of the joint member 11 to the tubular body 10 and the connection structure of the joint member 11 and the connection member 19 are the same as those of embodiment 1.

As described above, although the preferred embodiments have been described with reference to the drawings, various additions, modifications, and deletions can be made without departing from the scope of the present invention. Therefore, the present invention is also included in the scope of the present invention.

Description of reference numerals:

symbol a represents a reinforcing bar assembly;

symbol B represents a reinforcing bar joint;

symbol P represents a PC concrete body such as a beam or a column;

reference numeral 1 denotes a reinforcing bar;

reference numeral 2 denotes a rib;

reference numeral 6 denotes a bolt (fastening member);

reference numeral 7 denotes a template;

reference numeral 10 denotes a cylindrical body;

reference numeral 11 denotes a joint member;

reference numeral 12 denotes a main body portion;

reference numeral 13 denotes a male screw portion of the joint;

reference numeral 14 denotes an internal thread portion;

reference numeral 15 denotes a reinforcing bar external thread part;

reference numeral 17 denotes a through hole;

reference numeral 17a denotes a friction adjustment portion;

reference numeral 19 denotes a connecting member;

reference numeral 20 denotes a threaded hole;

reference numeral 27 denotes a coupling hole;

reference numeral 30 denotes a nut (fastening member).

Claims

1. A joint for reinforcing bars in which ends of a pair of reinforcing bars opposing in a length direction are connected to each other;

this steel bar joint includes:

a cylindrical body having an internal thread portion formed on an inner surface thereof;

a joint member having a joint male screw portion at one end; and

a connecting member for connecting the pair of joint members to each other so as to be displaceable in the longitudinal direction and in the direction orthogonal thereto,

a reinforcing bar male screw portion formed at an end portion of one of the reinforcing bars is screwed to one end portion of the cylindrical body, and the joint male screw portion at one end portion of the joint member is screwed to the other end portion.

2. The reinforcing bar joint according to claim 1, wherein the joint member has a body portion and the male screw portion, and the connecting member and the joint member are detachably connected by a fastening member in a state where the body portions of the pair of joint members are opposed to each other in the longitudinal direction.

3. The reinforcing bar coupler according to claim 2, wherein a body portion of the coupler member is interposed between the pair of coupling members.

4. A reinforcement assembly in which a plurality of reinforcements are arranged in parallel and coupled by means of ribs, a cylindrical body having an internal thread portion on an inner surface thereof is screwed to an external thread portion formed at an end portion of the reinforcement, the external thread portion of the reinforcement enters an axially inner portion of the internal thread portion, and an axially outer portion of the internal thread portion is exposed to the outside.

5. A precast reinforced concrete body, wherein in the reinforcing bar joint according to any one of claims 1 to 3, the tubular body and the reinforcing bar in the reinforcing bar joint are embedded in concrete, and a female screw portion of an outer end surface of the tubular body is exposed from an end surface of the concrete.