JP3983374B2 - Anchor re-tension method and re-tension jig - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an anchor re-tensioning method and a re-tensioning jig for re-tensioning an anchor by grasping and pulling an anchor head which is a head fixing tool for a tension member.
[0002]
[Prior art]
Earth anchors that tension and fix tension materials represented by stranded wires such as PC steel and stabilize the ground and various structures by the fixing force are widely applied to the ground and various structures.
[0003]
In the earth anchor, the grout is poured into the anchor hole in which the PC steel strand (tensile material) is inserted, and the fixing length of the PC steel strand is fixed to the ground etc. under the solidification of the grout. The tension jack is pulled and tensioned with a predetermined load. And the tensioned PC steel strand is grounded in a state where the tension at the corresponding fixing load is maintained under the anchor head as the head fixing tool fixed to the end (head). To be established.
[0004]
Here, in an earth anchor, particularly a permanent anchor, a tension state with a required fixing load must be continuously maintained during a period in which the target ground, various structures, and the like remain. And because the fixing load decreases with time due to the displacement of the ground, various structures, etc. and the elongation of the strands of PC steel, periodic inspection (soundness check) such as fixing load is required for permanent anchors Has been.
[0005]
Inspection of permanent anchor (earth anchor) anchorage load, etc. is usually measured under the re-tension of tension material such as wire from PC steel. In addition, when the fixing load is reduced or when the anchor is struck further, re-tensioning of the wire is required from the PC steel.
[0006]
Therefore, for example, a re-tensioning jack (re-tensioning device) that holds and fixes the anchor head that becomes the head anchoring tool of the permanent anchor and enables re-tensioning of the PC steel wire by pulling the anchor head is actually fair. No. 04-037957 discloses a hydraulic anchor maintenance jack.
[0007]
According to this re-tensioning jack (anchor maintenance jack), a plurality of wedge pieces are pushed out along the tapered surface of the inner cylinder slidably contacted with the outer cylinder, and the anchor head is gripped by the wedge pieces, and the contraction direction By pulling the fixing tool by sliding the inner cylinder on the wire, the PC steel wire is tensioned (re-tensioned). Then, the hydraulic pressure and traction displacement are measured with a static strain measuring instrument when the wire is re-tensioned from the PC steel, and the fixing load of the wire is obtained from the PC steel from the inflection point of the hydraulic pressure and displacement graph.
[0008]
[Problems to be solved by the invention]
However, since such a re-tensioning jack is generally a dedicated re-tensioning device that is distinguished from a general tensioning jack used in the tensioning process of a tendon, An increase is inevitable.
[0009]
Moreover, since this type of re-tensioning jack has a structure having an appropriate tensile load for each model, as in the case of the tensioning jack, preparation of a model corresponding to the tensile load of the anchor is required. However, there are not many types of retensioning jacks as there are tensing jacks, and this type of retensioning jack has a complicated structure and is expensive. A large burden is placed on capital investment.
[0010]
For this reason, an operator usually tries to support a minimum type of re-tensioning jack for a wide range of tensile loads, but re-tensions a small tensile load anchor with a large tensile load type. However, since it is not easy to finely adjust the tensile load, the soundness check may not be accurate. And since the number of re-tensioning jacks is small, if work at multiple work sites is required, it is often impossible to cover only with owned equipment.
[0011]
An object of the present invention is to provide an anchor re-tensioning method and a re-tensioning jig that enable anchor re-tensioning without using a dedicated re-tensioning jack.
[0012]
[Means for Solving the Problems]
In order to achieve this object, in the present invention, attention is paid to a wide variety of general tension jacks, and the use of the tension jack for the re-tensioning work of the anchor is intended. According to the anchor re-tensioning method of the present invention, the tensioning direction of the pooling head fixed around the anchor head under the insertion of the wedge piece along the inner tapered surface is interlocked with the tensioning operation of the tensioning jack. By moving the anchor head, the anchor head and the tension material are pulled together to re-tension the anchor. For example, after making the pooling head incapable of interlocking with the tensioning action of the tensioning jack, the wedge piece is moved in the tensioning direction under the sliding of the inner pipe with respect to the outer pipe interlocked with the tensioning action of the tensioning jack. By moving it, it is pulled out from between the inner tapered surface of the pooling head and the outer peripheral surface of the anchor head.
[0013]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
[0014]
As shown in FIG. 1, in the anchor re-tensioning jig 10 according to the present invention, a tensioning jack 14 which is a tensioning device for tensioning and fixing an anchor tensioning material (for example, PC steel strand) 12 is provided. It can be used as a re-tensioning device for re-tensioning the anchor after fixing. Then, the anchor head 16 as a head fixing tool of the tension member 12 is gripped and fixed, and the anchor head is pulled by pulling in the tension direction (right side in the figure) under the tension action of the tension jack 14. This re-tensioning jig 10 is configured so that the material, and hence the anchor, can be re-tensioned.
[0015]
This kind of anchor is on the extended end extended from the anchor plate 18 facing the head of the tension member 12 pulled under a predetermined fixing load, that is, the ground surface of the ground 17 to be fixed, etc. By fixing the anchor head 16 serving as a head fixing tool with the wedge 20 fitted or the like, the fixing force resulting from the fixing load of the tension material can be introduced into the ground or the like.
[0016]
Since the structure of the anchor itself is not the gist of the present invention, the description of the anchor itself is omitted here.
[0017]
In the re-tensioning jig 10 of the present invention, the anchor head 16 can be gripped and fixed by a combination of the pooling head 22 and the wedge piece 24.
[0018]
As can be seen from FIG. 2 in addition to FIG. 1, the pooling head 22 is a substantially cylindrical body that can be arranged around the anchor head 16, and the tip, that is, the inner surface of the end of the anchor plate side is the open end. It is formed as an inner tapered surface 22a having a small diameter on the side. The wedge piece 24 is supported by the support plate 26 so as to be swingable at least in a radial direction at a plurality of, for example, six locations at equal angles over the entire circumference of the inner tapered surface 22a, and an opening along the inner tapered surface. By holding the anchor head 16 under the pushing in the end direction, the anchor head and the pooling head 22 can be firmly connected and fixed.
[0019]
In this re-tensioning jig 10, for example, the pooling head 22 is first disposed around the anchor head 16, and then the wedge piece 24 supported by the support plate 26 extends along the inner tapered surface 22a. The position is inserted from the rear end of the pooling head 22. A pressing plate 28 for pressing the wedge piece 24 and the supporting plate 26 together by pressing the supporting end 24a of the wedge piece is disposed facing the rear surface of the supporting plate, and is biased in the pushing direction. A holding nut 32 is screwed to the rear end of the pooling head 22 so that a spring member 30 that applies force to the wedge piece 24, for example, a compression coil spring, is sandwiched between the holding plate and the holding plate.
[0020]
Next, the coupler 34 is fixed to the pooling head 22. The coupler 34 has a substantially bottomed cylindrical shape that can be disposed so as to cover the pooling head 22, and is fixed to the pooling head, for example, by screwing between a male screw 36 and a female screw 38. As shown in FIG. 1, a ram chair (also called a jack chair) 40 is disposed so as to further cover the coupler 34, and the tension jack 14 is placed under the ram chair. Is disposed.
[0021]
The tensioning jack 14 is a general center-hole type hydraulic jack used as a tensioning device in the anchor fixing process, and includes a tensioning side chamber 44-1 and a return side chamber that are separated and defined by the flange 42a of the piston 42. By either press-fitting pressurized oil from a hydraulic pump (not shown) via the corresponding ports 46-1 and 46-2 to one of 44-2 and discharging the pressurized oil from the other accompanying it, A tensioning operation for sliding and projecting the piston 46 in the tensioning direction (rightward in the figure) and a returning operation for contracting the piston are possible.
[0022]
The tension jack 14 is placed on the ram chair with the through hole (center hole) 50 of the piston 42 aligned with the insertion hole 48 of the ram chair 40.
[0023]
The tensioning jack 14 is used without any modification to a known one, but the structure of the tensioning jack itself is not the gist of the present invention, and therefore will not be described in detail here.
[0024]
The ram chair 40 itself is also known, and a known one used for anchor tension work can be used as it is. However, the ram chair in the present invention is arranged so as to cover the coupler 34. Therefore, it is necessary to re-tension separately from the ramchair for tension as it has an internal height that covers the coupler and secures a space that can ensure the movement of the coupler in the tension direction (right side in the figure). It is preferable to provide it as a ram chair.
[0025]
Here, the re-tensioning jig 10 of the present invention includes a pair of outer pipe 52 and inner pipe 54 that are slidable with respect to each other. The outer pipe and the inner pipe are connected to the center hole (through hole) of the tensioning jack. Hole) 50, and the ram chair is inserted through the ram chair insertion hole 48. As shown in FIGS. 1 and 2, the outer pipe 52 is connected and fixed to the coupler 34 and eventually the pooling head 22 under the screwing of the male screw 58 on the corresponding female screw 56. At the same time, the inner pipe 54 passes through the presser nut 32 and the presser plate 28 continuously, and is connected and fixed to the support plate 26 under the screwing of the external thread 62 to the corresponding female screw 60.
[0026]
In other words, in the present invention, the outer pipe 52 is moved along the axial direction of each pipe integrally with the coupler 34 and the pooling head 22, and the inner pipe 54 is integrally moved with the support plate 26 and eventually the wedge piece 24. It is possible.
[0027]
As shown in FIGS. 1 and 2, when the anchor is re-tensioned in the re-tensioning jig 10, the extension of the outer pipe from the rear end of the outer pipe 52, that is, the piston 42 of the tensioning jack. A tension member 64 engageable with the rear end 42b of the piston is fixed to the extended end portion so as to be movable integrally with the outer pipe in the axial direction of the outer pipe. As the tension member 64, for example, a tension nut that can be screwed onto the external thread 66 of the outer pipe 52 can be used, and this tension nut is usually screwed with respect to the outer pipe to a position adjacent to the rear end 42b of the piston. Arranged.
[0028]
In the re-tensioning jig 10 assembled as shown in FIG. 1, a tension nut (tension member) 64 is disposed on the rear end side of the piston 42 so as to be engageable with the piston rear end 42b. The outer pipe is caused by the sliding of the piston 42 in the tension direction (rightward in the figure), that is, the tensioning action of the tensioning jack 14 with the pressurization of the pressurized oil into the tension side chamber 44-1 via the port 46-1. 52 moves in conjunction with the tension direction under the engagement between the rear end of the piston and the tension nut.
[0029]
Then, the coupler 34 to which the outer pipe 52 is connected tries to pull the integral pooling head 22 in the tension direction with respect to the anchor head 16 and the wedge piece 24, so that the inner tapered surface 22a of the pooling head, the anchor head The anchor head is firmly fixed to the pooling head and pulled together with the pooling head under the further insertion of the wedge piece between the outer circumferential surface and the outer surface.
[0030]
Thus, by using this re-tensioning jig 10, the anchor can be re-tensioned using the tensioning jack. At the time of re-tensioning under a tensile load corresponding to the anchor fixing load, the integrity of the anchor is checked by, for example, inspection of disclosure using equipment as disclosed in Japanese Utility Model Publication No. 04-037957. Is called.
[0031]
After the soundness check is completed, the re-tension of the anchor is released by returning the piston 42 under the pressurization of pressurized oil into the return side chamber 44-2 via the port 46-2. Then, by pulling out the wedge piece 24 from between the inner tapered surface 22a of the pooling head and the outer peripheral surface of the anchor head 16, the anchoring of the anchor head by the pooling head 22 is released. There is a possibility that the rust piece is strongly bonded between the anchor head and the pooling head by vacuum bonding under close contact between the inner tapered surface and the outer peripheral surface of the anchor head. When this vacuum bonding occurs, a great amount of force is required to separate the inner taper surface 22a and the opposing surface of the wedge piece 24 from the outer peripheral surface of the anchor head 16, so the wedge piece when the re-tensioning jig 10 is disassembled. Cannot be pulled out easily.
[0032]
Therefore, in the re-tensioning jig 10 of the present invention, the tensioning jack 14 can be used also when the wedge piece 24 is pulled out from the inner tapered surface 22a of the pooling head and between the outer peripheral surfaces of the anchor head 16. It has become.
[0033]
As shown in FIGS. 1 and 2, for example, a diametrical through hole 68 is formed in the inner pipe 54, and a corresponding axially extending slit 70 that can be aligned with the through hole is formed in the outer pipe 52. It is provided in advance. Then, when the wedge piece 24 is pulled out after releasing the re-tension of the anchor, as shown in FIG. 3, it is used for re-tension so that the outer pipe 52 cannot be interlocked with the tension operation of the tension jack 14. Pull out the tension nut 64 from the outer pipe or pull it back to the outer pipe so that it can be engaged with the rear end 42b of the tension jack. The key 72 is inserted through the through hole 68 of the inner pipe through the slit 70 of the outer pipe (see FIG. 2).
[0034]
If the tensioning jack 14 is tensioned under pressure of pressurized oil into the tension side chamber 44-1 with the pulling key 72 shown in FIG. The inner pipe 54 is pulled and slid in the tension direction with respect to the outer pipe without the outer pipe 52 because the inner pipe 54 is not accompanied by the outer pipe 52. Since the support plate 26 moves integrally in the corresponding direction under the sliding of the inner pipe 54 in the tension direction, the pulling force under the tension action of the tension jack 14 is the pooling. The inner taper surface 22a of the head is a pulling force that pulls out the wedge piece 24 from the outer peripheral surface of the anchor head 16. Under this pulling force, the wedge piece is forcibly pulled out from between the inner tapered surface and the outer peripheral surface of the anchor head. It is.
[0035]
That is, according to the re-tensioning jig 10 of the present invention, the tensioning jack 14 can be used for pulling out the wedge piece 24, so the wedge piece is placed on the inner tapered surface 22a of the pooling head and the outer peripheral surface of the anchor head 16. Even if vacuum bonding is performed, peeling of the opposing surface of the wedge piece from the inner tapered surface and the outer peripheral surface of the anchor head can be reliably and easily ensured under the tensioning operation of the tensioning jack.
[0036]
In this case, the holding nut 32 is attached to the pooling head so that the space for moving the support plate 26 and the holding plate 28 in the pulling direction (rightward in the drawing) inside the pooling head 22 can be secured long. On the other hand, it is good to screw in advance as much as possible.
[0037]
Further, here, the extraction of the wedge piece 24 using the tensioning jack 14 has been described. However, the wedge piece can be forcibly extracted without using the tensioning jack. As shown in FIG. 4, in this case as well, the tension nut 64 is removed from the outer pipe 52, for example, after which the extraction nut 74 is screwed onto the corresponding male thread 76 under the inner pipe 54. It is mounted around the rear end (see FIG. 2).
[0038]
Then, when the extraction nut 74 is further rotated in the screwing direction with respect to the inner pipe 54 at a position engaged with the rear end 52a of the outer pipe 52 as shown in the drawing, the screwing of the drawing nut with respect to the inner pipe 54 Under the force, the inner pipe tends to move in the tension direction with respect to the outer pipe. Under this force, the wedge piece 24 is located between the inner tapered surface 22a of the pooling head and the outer peripheral surface of the anchor head 16. It is forcibly pulled out from.
[0039]
Such a configuration in which the wedge piece 24 can be pulled out by the pulling nut 74 is effective when the tensile load is relatively small.
[0040]
Then, after the wedge piece 24 is forcibly pulled out from between the inner tapered surface 22a of the pooling head and the outer peripheral surface of the anchor head 16 under the tensioning action of the tensioning jack 14 or the rotation of the pulling nut 74, the assembly is performed. If the constituent members are eliminated under the reverse process, the re-tensioning jig 10 can be easily disassembled.
[0041]
As described above, according to the anchor re-tensioning method of the present invention, it is sufficient to pull the pooling head 22 fixed to the anchor head 16 under the tensioning action of the tensioning jack 14. Without use, the anchor can be re-tensioned by a tensioning jack. In other words, when the anchor is re-tensioned, it is sufficient to re-use the tension anchor 14 that was used during the tensioning operation of the anchor. Therefore, re-tensioning with an appropriate tensile load can be easily ensured and the accuracy is excellent. The health level of the anchors can be checked.
[0042]
And since it is not necessary to prepare a variety of re-tensioning jacks for each tensile load, an increase in the number of incidental devices at the time of construction of the earth anchor can be sufficiently suppressed, and the burden on the equipment investment of the installer is reduced.
[0043]
Further, the wedge piece 24 that is firmly fitted between the inner tapered surface 22a of the pooling head and the outer peripheral surface of the anchor head 16 is caused by the tensioning action of the tensioning jack 14 or the rotation of the pulling nut 74. Since it is easily pulled out, it is possible to prevent complication of work after re-tensioning.
[0044]
And, according to the anchor re-tensioning jig 10 of the present invention, under the combination with the tensioning jack 14, the above-mentioned re-tensioning method can be appropriately performed, and the re-tensioning of the anchor with the tensioning jack is easy, And it will definitely be possible.
[0045]
Here, in the embodiment of the present invention, a configuration in which the separate coupler 34 and the outer pipe 52 are integrally connected under the screwing between the external thread 58 and the internal thread 56 is illustrated. For example, the coupler and the inner pipe may be integrally connected and fixed in advance as one member by welding or the like. However, if the coupler 34 and the outer pipe 52 are separate members, an increase in the size of the single member can be prevented, and assembly, disassembly, and transportation operations are facilitated.
[0046]
In addition, the configuration in which the coupler 34 is connected to and fixed to the pooling head 22 by screwing between the male screw 36 and the female screw 38 is illustrated. However, the coupler is detachable from the pooling head and has a pulling direction. In other words, since it is sufficient that the inner pipe 52 and the like are connected so as to be integrally movable in the axial direction, the present invention is not limited to a combination of a male screw and a female screw. The coupler and the pooling head may be connected.
[0047]
In the embodiment of the present invention, the tension nut 64 is illustrated as a tension member that can be screwed to the external thread 66 of the outer pipe 52, but the tension member is detachable from the outer pipe, and Since it is sufficient to be connected to the axial direction so as to be integrally movable, it is not limited to a tension nut. For example, a ring-shaped member that can be fixed to the outer pipe by a set screw or the like, or corresponding in the diameter direction of the outer pipe. A bar-like member or the like that can be disposed through the through hole may be used as the tension member.
[0048]
However, if the tension nut 64 is used as a tension member, although it can be easily attached and detached, the integration with the outer pipe 52 is appropriately performed, so that workability and work reliability are further improved. .
[0049]
Further, in the embodiment of the present invention, an anchor using one PC steel stranded wire as a tension member 12 is illustrated, and this one anchor head 16 is specifically used as a target of fixing and traction by the pooling head 22. However, the number of strands of PC steel is not limited to this, and it goes without saying that anchor heads for other numbers may be used.
[0050]
Furthermore, the general shape of the anchor head 16 is generally cylindrical, but is not limited to this, and is intended for anchor heads such as a stepped shape having a stepped portion on the peripheral surface and a polygonal planar shape such as a hexagon. It is good also as a structure.
[0051]
And although the strands of PC steel are embodied as the tendon members 12, the present invention is not limited to this, and the present invention can also be applied to other tendon members, for example, anchors such as PC steel bars.
[0052]
The above-described embodiments of the present invention are for explaining the present invention, and are not intended to limit the present invention. All modifications, alterations, etc. within the technical scope of the present invention are included in the present invention. It goes without saying that it is included in.
[0053]
【The invention's effect】
As described above, according to the anchor re-tensioning method according to the present invention, the tension anchor used during the tensioning operation of the anchor can be used for re-tensioning without using a re-tensioning jack. Re-tensioning with load can be easily ensured, and the integrity of anchors with excellent accuracy can be checked.
[0054]
And since it is not necessary to prepare a variety of re-tensioning jacks for each tensile load, an increase in the number of incidental devices at the time of construction of the earth anchor can be sufficiently suppressed, and the burden on the equipment investment of the installer is reduced.
[0055]
Furthermore, since the wedge piece firmly fitted between the inner taper surface of the pooling head and the outer peripheral surface of the anchor head is easily pulled out under the tensioning action of the tensioning jack or the rotation of the pulling nut, Complicated work after re-tensioning can be prevented.
[0056]
According to the anchor re-tensioning jig of the present invention, the above-described re-tensioning method can be properly performed in combination with the tensioning jack, and the re-tensioning of the anchor with the tensioning jack is easy and reliable. It becomes possible.
[0057]
Furthermore, if the tension member is a tension nut that can be screwed onto the male thread of the outer pipe, it can be easily attached and detached, but it is properly integrated with the outer pipe. The certainty is further improved.
[0058]
Further, if the support plate of the wedge piece can be pushed under the biasing force of the spring means, the wedge piece can be easily and reliably pushed between the inner tapered surface of the pooling head and the outer peripheral surface of the anchor head. . Then, the strength of the biasing force from the wedge piece can be easily adjusted by screwing the holding nut onto the rear end of the opening of the pooling head.
[0059]
Furthermore, if the coupler and the outer pipe are separated, and the outer pipe can be connected to the pooling head via this coupler, the work between the outer pipe and the pooling head can be avoided without complicating the work and increasing the size of the single member. Can be connected and fixed.
[Brief description of the drawings]
FIG. 1 is a schematic side view of a partial fracture of an anchor re-tensioning jig according to the present invention during re-tensioning.
FIG. 2 is a schematic exploded perspective view of an anchor re-tensioning jig.
FIG. 3 is a schematic side view of a partially broken jig of an anchor re-tensioning tool, showing one embodiment of a wedge piece drawing process.
FIG. 4 is a schematic side view of a partially broken jig of an anchor re-tensioning tool, showing another form of the wedge piece drawing process;
[Explanation of symbols]
10 Anchor re-tensioning jig
12 Tension material (PC steel strand)
14 Tension jack
16 Anchor head
22 Pooling head
22a Inner taper surface of the pooling head
24 wedge pieces
26 Support plate
30 Spring means (compression coil spring)
32 Retaining nut
34 Coupler
52 Outer pipe
54 Inner pipe
64 Tension member (Tension nut)
68 Inner pipe through hole
70 Outer pipe slit
72 Extraction key
74 Pull-out nut

Claims (9)

 This is a re-tensioning method for an anchor in which the tension material pulled under the tensioning action of the tensioning jack is fixed under the fixing load corresponding to the tensile load by fixing the anchor head at its head. The pooling head fixed around the anchor head under the insertion of a wedge piece along the taper surface is moved in the tension direction under the sliding of the outer pipe interlocked with the tension action of the tension jack. As a result, the anchor head and the tension material are pulled together to re-tension the anchor, and after the pooling head cannot be interlocked with the tension operation of the tension jack, the wedge piece is tensioned. The inner taper surface of the pooling head is moved in the tension direction under the sliding of the inner pipe with respect to the outer pipe in conjunction with the tensioning action of the jack for use. Re tensioning method anchor pulled out between the outer peripheral surface of the anchor head.  This is a re-tensioning method for an anchor in which the tension material pulled under the tensioning action of the tensioning jack is fixed under the fixing load corresponding to the tensile load by fixing the anchor head at its head. The pooling head fixed around the anchor head under the insertion of a wedge piece along the taper surface is moved in the tension direction under the sliding of the outer pipe interlocked with the tension action of the tension jack. The rear end of the outer pipe after the anchor head and the tension member are pulled together to re-tension the anchor, and the pooling head cannot be interlocked with the tension operation of the tension jack. The wedge piece is pooled by the backward movement of the inner pipe with respect to the outer pipe as the extraction nut rotates with respect to the inner pipe at the position where it engages with the outer pipe. Re tensioning method anchor pulled out between the outer peripheral surface of the inner tapered surface and the anchor head head. The outer pipe and the inner pipe are arranged by penetrating through the center hole provided in the piston of the tensioning jack, and each pipe slides in conjunction with the tensioning action of the tensioning jack under the engagement with the rear end of the piston. The method for re-tensioning an anchor according to claim 1 or 2 , wherein the anchor is re-tensioned.  A pooling head which is a substantially cylindrical body which can be arranged around the anchor head and which has an inner tapered surface having a small diameter on the opening end side on the inner surface of the tip portion; A plurality of wedge pieces for fixing the pooling head to the anchor head under gripping by fitting along the inner taper surface of the rod; a center hole of the tension jack, and an insertion hole of the ram chair on which the tension jack is placed And an outer pipe connected at one end to the pooling head; an inner pipe slidably inserted into the outer pipe so as to be freely rotatable and connected at one end to the support plate of the wedge piece; A tension member fixed to the outer pipe so that it can be engaged behind the piston of the tensioning jack and under sliding of the piston in the tensioning direction; The pulling head, which is fixed to the anchor head, can be pulled in the tension direction under the movement of the outer pipe in conjunction with the tensioning action of the tensioning jack, and the inner side in the tension direction without the outer pipe. An anchor re-tensioning jig in which the wedge piece can be pulled out between the inner tapered surface of the pooling head and the outer peripheral surface of the anchor head by pulling the pipe. The inner pipe has an insertion hole into which the extraction key can be inserted as a through-hole in the diametrical direction behind the piston of the tension jack, and the outer pipe ensures movement of the extraction key in the axial direction. The inner pipe is pulled in the tension direction by the tensioning operation of the tensioning jack after removing the tension member from the predetermined position and after inserting the extraction key. 5. The anchor re-tensioning jig according to claim 4, which is made possible. The inner pipe is formed with a screw at the end extending backward from the outer pipe, and a pulling nut is screwed onto the male screw, and after the tension member is removed from a predetermined position, after engagement of the outer pipe rear accompanying screwing of the nut, by further rotation of the pull nut in the screwing direction, claim 4 or the movable inner pipe tensioning direction relative to the outer pipe 5. A jig for re-tensioning an anchor according to 5 . Tension member is a threadedly tension nut male thread of the outer pipe, under the screwing into Konooneji, to 4 claims is immovably secured axially outer pipe around 6 The anchor re-tensioning jig according to any one of the above. An inner taper surface of the pooling head is formed by a biasing force of a spring member comprising a compression coil spring that is screwed into the rear end portion of the opening of the pooling head and interposed between the holding nut and the support plate. The anchor re-tensioning jig according to any one of claims 4 to 7 , wherein the jig is biased in the pushing direction between the anchor head and the outer peripheral surface of the anchor head. The anchor according to any one of claims 4 to 8 , wherein the coupler is fixed around the pooling head so as to cover the pooling head, and the outer pipe is connected to the pooling head through fixing at one end to the coupler. Re-tension jig.

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