JP2005090032A - Joint structure for wire rod - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide the safe joint structure for wire rods with excellent workability without lowering the toughness of the wire rod. <P>SOLUTION: In the structure for joining anchor reinforcements 10 (the wire rod) having an enlarged diameter part 12 at the tip, to a structure through a connecting coupler 20 mounted to the structure, the connecting coupler 20 is formed in a cylindrical shape with a locking part for the enlarged diameter part 12 of the anchor reinforcement 10, and the enlarged diameter part 12 of the anchor reinforcement 10 is locked to the locking part of the connecting coupler 20. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a joining structure of wire rods in civil engineering structures and building structures.

  For joining various structures, for example, pile heads of pile foundation structures and footings and foundation slabs, and steel column bases, threaded wire rods are usually used as structures and anchor plates as anchor bars. This is done by bonding. However, since these anchor bars have a cross-sectional defect due to the threading process, when an excessive tensile force is generated, the anchor bars are broken at the thread portion. For this reason, the tough performance (elongation performance) of the anchor muscle is determined by the yield strength of the threaded portion, and there is a problem that the original tough performance of the wire is not sufficiently exhibited. Also, there are cases where welding is performed without threading, but in this case, high-strength steel cannot be welded, and the material properties of the wire change due to welding, and the toughness of the wire at the weld location There are problems such as lowering.

Conventionally, there has been disclosed a wire joining structure capable of exhibiting the original toughness performance by joining the wire by the following method without subjecting the wire to threading (Patent Literature). 1).
(1) By inserting the anchor bar 110 that has heated the tip 111 into the end plate 132 of the pile head 131 in which the anchor bar fixing hole 133 that has been spread downward is preliminarily processed, the tip 111 becomes the anchor bar fixing hole. An anchor reinforcement joining structure in which the anchor reinforcement 110 is joined to the pile head 131 by forming a diameter-expanded portion 112 by fluid deformation in 133 (see FIG. 9A).
(2) The anchor bar 110 having the enlarged diameter portion 112 at the tip is passed through the joint plate 134 in which the anchor bar fixing hole 133 extending downward is processed in advance, and the joint plate 134 is fixed to the end plate 132 of the pile head 131. By doing so, the anchor muscle 110 is joined to the pile head 131, and the anchor muscle joining structure (see FIG. 9B).
JP 2002-242176 A ([0010] to [0021], FIGS. 1 and 4)

However, each of the above-described conventional anchor muscle joint structures has the following problems.
(1) It takes time and effort to heat the tip of each anchor to the extent that it has fluidity, and there is a risk in handling an anchor heated to a high temperature.
(2) It is difficult to handle the joint plate in which a plurality of anchor bars are inserted, and it takes time to fix the joint plate to the end plate of the pile head.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to propose a wire joining structure that is safe and excellent in workability without reducing the toughness of the wire.

  In order to solve such a problem, the invention according to claim 1 is a structure in which a wire having a diameter-expanded portion at the tip and a structure are joined via a connection coupler attached to the structure. The connection coupler has a locking portion for the expanded diameter portion of the wire, and is formed in a cylindrical shape, and the expanded diameter portion of the wire is engaged with the locking portion of the connection coupler. It is characterized by being stopped.

  In such a wire joining structure, a wire having an enlarged diameter portion at the tip is inserted into a connecting coupler joined to a structure or the like, and the wire is locked by the enlarged diameter portion and the engaging portion of the connecting coupler, It is joined to a structure or the like without coming out of the connecting coupler. Therefore, there is no need to thread the wire, and there is no decrease in the yield strength of the wire due to the reduced cross-sectional area. Therefore, bonding to the structure while maintaining the inherent strength and toughness of the wire It is possible to perform.

  In addition, if the latching | locking part of a connection coupler is formed by giving a corner cut (taper) process to the contact part with the diameter-expanded part of a wire, for example, the diameter-expanded part of a wire will be latched by the taper part. Therefore, it is possible to perform the function without causing a deviation, which is preferable.

  Further, if a steel rod having an enlarged diameter portion at both ends is used as a wire, it is preferable that the joining work to an anchor plate or a structure can be easily performed by fastening via a connecting coupler. In addition, since processing that reduces the cross-sectional area of the steel rod is not performed, the proof stress of the wire can be maximized, and this is effective when using a small-diameter steel rod. In particular, the use of high-strength steel bars with a higher yield strain than ordinary steel materials expands the elastic range, for example, the seismic performance as well as the damage limits of the joints between piles and foundations and steel column base joints. It is possible to improve dramatically, which is preferable.

  The invention according to claim 2 is the wire joining structure according to claim 1, wherein the connection coupler has a cylindrical shape, and a screw portion is formed on an outer peripheral portion thereof, and the screw portion has the structure. It is characterized by being fastened to objects.

  Such a wire joining structure has a threaded portion formed on the wire insertion hole (bolt hole) of the structure when the wire is joined to the structure because the outer periphery of the connecting coupler is threaded. Since the joining of the wire is completed by fastening to the wire, a simple joining operation becomes possible.

  Here, if an end plate having a bolt hole for fastening the connection coupler is used at the joint between the structure and the wire rod, the connection between the wire rod and the structure can be achieved simply by screwing the connection coupler into the end plate. Since it is completed, the operation is easy and preferable. Furthermore, if a recess for accommodating the enlarged diameter portion is formed in advance on the back surface of the bolt hole, the enlarged diameter portion of the steel rod protruding from the connecting coupler is connected to the bolt hole when the wire rod is joined to the structure. By providing the structure on the back surface, it is preferable that the connection coupler is not sufficiently fastened to the end plate, and the fastening can be surely performed. If a thick end plate is used, it is possible to fasten the connecting coupler to the end plate without protruding the diameter of the steel rod from the bolt hole. The recess formed on the back surface is not necessarily required.

  According to the joining structure of the wire rod of the present invention, since the wire rod is not threaded, the function as an anchor bar is exhibited without reducing the inherent strength and toughness of the wire rod, and the seismic performance of the structure Can be improved. In addition, since the joining of the wire rod to the structure or the like is performed via the connection coupler, it can be easily performed, and the construction can be performed safely and in a short period of time.

  DESCRIPTION OF EMBODIMENTS Preferred embodiments of the present invention will be described in detail with reference to the drawings. In the following description, the same reference numerals are used for the same elements, and duplicate descriptions are omitted.

The present embodiment is an aspect in which the wire rod joining structure according to the present invention is used when the pile head of a concrete pile is joined to the foundation concrete.
FIG. 1 is a perspective view showing a wire joining structure 1 according to the present invention, and FIG. 2 is a sectional view thereof.

  As shown in FIG. 1, in the wire joining structure 1 according to the present invention, connection couplers 20 are installed at both ends of an anchor bar (wire) 10 made of a high-strength round steel bar (a steel bar with a high yield strain). One end of the anchor bar 10 is connected to the pile head 31 of the columnar concrete pile 30 and the other end is connected to the nut 42 of the anchor plate 40 via the connection coupler 20. The pile head 31 is provided with an end plate 32 provided with a plurality of bolt holes. By fastening the connection coupler 20 to the bolt holes provided in the end plate 32, the anchor bars 10 are end-attached. It is fixed to the plate 32. Further, the anchor reinforcement 10 is embedded in the foundation concrete 2 placed on the top of the concrete pile 30. The concrete pile 30 and the foundation concrete 2 are integrally joined by this wire joining structure 1 (see FIG. 2).

Details will be described below.
3A and 3B are views showing the anchor muscle 10, wherein FIG. 3A is a side view and FIG. 3B is an enlarged perspective view of an enlarged diameter portion. 4A and 4B are diagrams showing the connection coupler 20, wherein FIG. 4A is a perspective view and FIG. 4B is a side sectional view. 5A and 5B are diagrams showing the end plate 32, where FIG. 5A is a plan view and FIG. 5B is a side sectional view.

  As shown to Fig.3 (a), the anchor reinforcement 10 consists of a high-strength steel rod of the predetermined length which has the enlarged diameter parts 12 and 12 in both ends. As shown in FIG. 3 (b), the enlarged diameter portions 12, 12 provided at both ends of the anchor muscle 10 strike the tip in the axial direction with both ends of the anchor muscle 10 heated. The end of the steel rod is formed to have a larger diameter than the shaft 11. The shape of the enlarged diameter portion 12 is not limited as long as the diameter of the enlarged diameter portion 12 is such that the anchor muscle 10 does not come out of a connection coupler 20 described later.

As shown in FIG. 4A, the connection coupler 20 has a cylindrical shape, the inner diameter is slightly larger than the diameter of the shaft portion 11 of the anchor muscle 10, and the outer diameter is the maximum diameter of the expanded portion 12 of the anchor muscle 10. Bigger than. Further, the outer periphery of the connection coupler 20 has a threaded portion 21 that is threaded. Further, as shown in FIG. 4 (b), the contact portion of the connecting coupler 20 with the enlarged diameter portion 12 of the anchor bar 10 is subjected to corner cutting at 30 ° to 45 °, and the enlarged diameter portion. 12 has a taper portion 23 that locks 12. Further, chamfering is performed on two opposing surfaces as the tool allowance 22 on the outer peripheral portion of the connection coupler 20 opposite to the contact portion with the enlarged diameter portion 12 (see FIG. 4B).
The outer diameter, inner diameter, length, threading standard, etc. of the connecting coupler 20 depend on the diameter of the shaft portion 11 of the anchor bar 10, the proof stress, the maximum diameter of the expanded portion 12, the material of the object to be joined, and the like. Set as appropriate. Here, by setting the yield strength of the screw portion 21 provided on the outer periphery of the connection coupler 20 to be equal to or greater than the yield strength of the shaft portion 11 of the anchor muscle 10, the tough performance of the original shaft portion 11 is sufficiently exhibited. This is preferable.

An end plate 32 as shown in FIG. 5 is installed on the pile head 31 of the concrete pile 30 to enable the anchor bars 10 to be joined. The end plate 32 is made of a steel plate processed into a ring shape in plan view, and a plurality of bolt holes 33 are provided at predetermined intervals. Here, the bolt hole 33 is threaded on the inner surface so that the connection coupler 20 can be fastened.
In addition, the recessed part 34 which has a depth comparable as the protrusion length from the connection coupler 20 of the enlarged diameter part 12 of the anchor reinforcement 10 is formed in the pile head 31 upper surface under each bolt hole 33, and an anchor reinforcement Ten diameter-expanded portions 12 can be accommodated (see FIG. 6B).

As shown in FIG. 6 (a), the anchor bar 10 used in the present embodiment is inserted in advance into the two connecting couplers 20 and 20, and has enlarged diameter portions 12 and 12 at both ends. ing.
As shown in FIG. 6 (b), the connecting coupler 20 is screwed into a bolt hole 33 provided in the end plate 32, and the joint between the anchor bar 10 and the concrete pile 30 protrudes from the connecting coupler 20. The enlarged diameter portion 12 at the tip of the anchor muscle 10 is in contact with the bottom surface of the recess 34 provided in the pile head 31. In addition, if the plate | board thickness of the end plate 32 is thick and sufficient screw strength can be expressed with respect to the tension | tensile_strength force loaded on the anchor muscle 10, without forming the recessed part 34 in the pile head 31, the anchor muscle 10's It is good also as a structure which accommodates the enlarged diameter part 12 in the bolt hole 33 of the end plate 32, making it closely_contact | adhere to the concrete of the pile head part 31. FIG.

On the other hand, as shown in FIG. 7B, the connecting coupler 20 is screwed into the nut 42 of the anchor plate 40 at the joint between the anchor bar 10 and the anchor plate 40, and the anchor bar protruding from the connecting coupler 20. Ten diameter-expanded portions 12 are in contact with the steel plate 41 of the anchor plate 40. And the anchor reinforcement 10 to which this anchor plate 40 was attached is embed | buried in the foundation concrete 2 cast | placed by the upper part of the concrete pile 30, and the concrete pile 30 and the foundation concrete 2 are joined.
As shown in FIGS. 7A and 7B, the anchor plate 40 is formed by welding a square steel plate 41 to a nut 42. However, the shape of the anchor plate 40 is limited. It is not a thing.

  As described above, since the wire joining structure 1 according to the present invention joins the anchor bar 10 to the end plate 32 and the anchor plate 40 only by fastening with the connecting coupler 20, as shown in FIG. It becomes possible to easily integrate the pile 30 and the foundation concrete 2.

  In addition, since one end of the anchor bar 10 is brought into contact with the concrete of the pile head portion 31 by the wire joining structure 1 according to the present invention, the pulling force acting on the anchor bar 10 is connected from the enlarged diameter portion 12. It is transmitted to the taper portion 23 of the coupler 20 and further transmitted from the screw portion 21 of the connection coupler 20 to the end plate 32. Further, since the other tip of the anchor bar 10 is brought into contact with the steel plate 41 of the anchor plate 40, the pulling force acting on the anchor bar 10 is transmitted from the enlarged diameter part 12 to the taper part 23 of the connection coupler 20, Furthermore, it is transmitted from the threaded portion 21 of the connecting coupler 20 to the nut 42 and further transmitted from the nut 42 to the foundation concrete. For this reason, the pulling force applied to the anchor bar 10 is dispersed without concentrating on one point, so that the strength inherent in the steel bar can be fully utilized.

As mentioned above, although an example about a suitable embodiment was explained about the present invention, the present invention is not restricted to the embodiment concerned, and a design change is possible suitably in the range which does not deviate from the meaning of the present invention.
For example, in this embodiment, the wire joining structure according to the present invention is used for joining the pile head and the structure foundation, but the present invention is not limited to this, and various structures that require joining by the wire. It goes without saying that it can be used for things.
In addition, the steel rod is inserted into the connecting coupler and then the diameter-expanded portion of the steel rod is processed. However, the present invention is not limited to this. It is good also as a structure which attaches a connection coupler of a type.
Moreover, although it was set as the column-shaped thing as a concrete pile, it cannot be overemphasized that a pile shape is not limited.

Next, the result of having conducted the verification experiment about the tough performance of the joining structure of the wire material by this invention is shown.
In this demonstration experiment, a tensile test result (comparative example) in a state where a threaded steel bar (φ9.2 mm-PC steel bar-C type: allowable tension load 57.9 kN) is nut-joined and diameter expansion A tensile test result (invention example) in a state where a steel bar having a portion (φ11 mm-PC steel bar-type A: allowable tension load 60.2 kN) is joined through a connecting coupler is compared.

  FIG. 8A shows the result of an experiment using the former steel rod subjected to threading, and the threaded portion is broken when the shaft portion is extended by about 6400 μm. On the other hand, the latter steel rod joined by the connection coupler according to the present invention is broken when the shaft portion extends 57000 μm. That is, it can be seen that the wire joint structure according to the present invention increases the elongation of the shaft portion of the PC steel having approximately the same allowable tension load by about 8.9 times.

  From this result, for example, when it is estimated that the limit rotation nucleus at the time of the ultimate limit of a ready-made concrete pile having a pile diameter of 600 mm is 70 cm, the length of the anchor is 70 cm. In the structure, it became about 1/15 rad, and it became clear that the seismic performance of the pile head joint part was drastically improved.

It is a perspective view which shows the condition which installed the joining structure of the wire which concerns on this invention in the pile head of a concrete pile. It is sectional drawing which shows the joining structure of the wire which concerns on this invention. It is a figure which shows an anchor muscle, (a) is a side view, (b) is an expansion perspective view of a diameter-expansion part. It is a figure which shows a connection coupler, (a) is a perspective view, (b) is a sectional side view. It is a figure which shows an end plate, (a) is a top view, (b) is a sectional side view. It is a figure which shows the installation condition of an anchor reinforcement, (a) is a whole figure of the anchor reinforcement inserted in the connection coupler, (b) is an expanded sectional view of the junction part to the end plate of an anchor reinforcement. It is a figure which shows an anchor plate, (a) is a top view, (b) is sectional drawing. It is a figure which shows a proof experiment result, (a) is a drawing test result by the steel bar which gave the thread process, (b) is a drawing test result of the steel bar by this invention. It is a figure which shows the joining structure of the conventional anchor muscle.

Explanation of symbols

1 Wire connection structure 10 Anchor bar (wire)
12 Expanded diameter part 20 Connecting coupler 21 Screw part 23 Taper part

Claims (2)

In the structure in which the wire and the structure having an enlarged diameter portion at the tip are joined via a connection coupler attached to the structure,
The connection coupler has a locking portion of the enlarged diameter portion of the wire, and is formed in a cylindrical shape,
The wire rod joining structure, wherein the diameter-expanded portion of the wire rod is locked to the locking portion of the connection coupler. The connection coupler has a cylindrical shape, and a thread portion is formed on the outer peripheral portion thereof.
The wire threaded joint structure according to claim 1, wherein the screw portion is fastened to the structure.

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