JP4340642B2 - Shim for tension adjustment and method for unloading tension of PC steel - Google Patents

Description

  The present invention relates to a shim for adjusting the tension of a strained PC steel and a method for unloading the tension of a PC steel in a PC structure using the shim. In particular, the present invention relates to a shim that can be easily attached to and detached from the outer periphery of each PC steel material at a fixing portion of the PC steel material, and a method for unloading the tension of the PC steel material in a PC structure using this shim.

  In the PC structure, the fixing portion of the PC steel material is mainly composed of a wedge for holding the PC steel material and a wedge receiver having a fitting hole for fitting the wedge. And the fixing | fixed part improves the durability of PC structure by applying a load to PC structure by transmitting the tension | tensile_strength of PC steel material which was tensioned to a bearing surface via a wedge wedge receiver. By the way, such a fixing portion is usually provided with a member for adjusting the load applied to the PC structure in addition to the wedge / wedge receiver, and one of them is a shim.

  As a shim used for a PC structure, there is a shim formed into an annular shape or a cylindrical shape by combining a plurality of divided pieces having an arc cross section. As described in Patent Document 1, an annular one is used in a fixing portion of a PC steel material using an anchor disk in which tension forces of a plurality of PC steel materials are concentrated and arranged.

  The annular shim is disposed on the outer periphery of the PC steel material between the anchor disk and the bearing surface, and transmits the tension of the PC steel material received from the anchor disk to the bearing surface. At this time, the tension force of the PC steel applied to the PC structure can be adjusted by laminating the annular shim in the axial direction of the PC steel. Specifically, when the number of shims laminated in the axial direction of the PC steel material is increased, the anchor disk to which the tension force of the PC steel material is transmitted via the wedge is arranged in a direction away from the bearing surface. The tension force transmitted to the bearing surface through the annular shim increases. Conversely, if the number of shims is reduced, the tension transmitted to the bearing surface is reduced.

  In addition, the annular shim is configured so as not to be disassembled and removed from the outer periphery of the PC steel material when pressure is applied in the axial direction thereof. For example, in Patent Document 1, the diameter of an annular shim is made larger than that of an anchor disk to increase the frictional force between the shim and the bearing surface, thereby making it difficult for the shim to come off from the outer periphery of the PC steel material.

  On the other hand, a cylindrical thing is arrange | positioned in the outer periphery of each PC steel material in the bearing surface side rather than a wedge receptacle, and is used for unloading the tension force once introduced into each PC steel material. Such a cylindrical shim is used in, for example, a tension monitoring unit 10 for monitoring the tension of the PC steel material 1 as shown in FIG. At the fixing part using a cylindrical shim, the tension force of the tensioned PC steel material 1 excludes the tension of the wedge 2 that grips the PC steel material 1, the grip 3 that inserts the wedge 2 (the wedge receiver), and the tension force of the PC steel material 1. It is transmitted to the bearing surface G via a cylindrical shim 4 used for loading, a load cell 5 for measuring tension, a bearing ring 6 for aligning the load cells 5, and an anchor disk 8 for consolidating the PC steel material 1. At this time, the PC steel material 1 not provided with the tension monitoring unit 10 has the wedge 2A fitted directly into the fitting hole 8Ha of the anchor disk 8, but the anchor disc 8 fitted with the monitoring unit 10 is fitted. A hole-filling ring 7 is fitted in the joint hole 8H so that the end surface of the bearing ring 6 and the end surface of the anchor disk 8 are brought into contact with each other in a plane. When unloading the tension in the fixing portion, the PC steel material 1 is again tensioned using a jack or the like, and the shim 4 is removed after the grip 3 does not press the shim 4 strongly in the bearing surface G direction. When the re-tension of the PC steel material 1 is loosened, the PC steel material 1 becomes loose by the length of the shim 4 in the axial direction, so that the tension force introduced into the PC structure can be unloaded.

  By the way, the cylindrical shim composed of a plurality of divided pieces as described above has been conventionally joined by spot-welding the portions that come into contact with the divided pieces. Then, when removing the shim from the PC steel material, the spot welded portion was hit with a scissors or the like to release the joining of the divided pieces.

JP-A-6-262618

  However, the conventional shim as described above can be easily attached to the fixing portion of the PC steel for the following reasons, and can be easily removed when releasing the tension of the PC steel. There wasn't.

  In the fixing part of the PC steel material, a pressure in tons is applied in the bearing surface direction by a wedge that holds the PC steel material. At this time, the same pressure is also applied in the axial direction of the shim, and the shim is compressed in the axial direction. Therefore, when a shim composed of a plurality of divided pieces is joined by spot welding, if the joint by this spot welding is not sufficient, the shim is decomposed into a plurality of divided pieces by the pressure applied in the axial direction of the shim. There is. Further, if spot welding is excessively performed when joining the divided pieces so that the shim does not decompose, it becomes difficult to disassemble the shim this time. Of course, if spot welding can be performed without excess or deficiency, it is possible to form a shim that can be easily disassembled by striking the spot welded part with a scissors without being disassembled when it is placed on the fixing part of PC steel. is there. However, it is difficult to perform such spot welding without excess or deficiency unless it is a person who is proficient in welding work, and even a person who is proficient in welding work is difficult to perform the same degree of spot welding for each welding work. .

  Therefore, the main object of the present invention is that it is easy to attach to and remove from the outer periphery of the PC steel material at the fixing portion of the PC steel regardless of the level of proficiency with respect to the welding work of the operator, and when placed on the fixing portion, the PC The object is to provide a shim that does not decompose by the tension of steel.

  Another object of the present invention is to provide an unloading method in a fixing portion of a PC steel material using the shim.

  The present invention achieves the above object by constituting a shim by fastening a cylindrical member formed by combining a plurality of non-cylindrical divided pieces with a fastening mechanism.

  The present invention is a load adjusting shim disposed on the outer periphery of a PC steel material in order to adjust the tension of the PC steel material. The shim includes a cylindrical member formed by combining a plurality of non-cylindrical divided pieces, and a tightening mechanism that tightens the divided member so as not to be divided when the cylindrical member is attached to the outer periphery of the PC steel material. It is characterized by that.

  Hereinafter, the tension adjusting shim of the present invention will be described in detail.

  The shim includes a cylindrical member formed by combining a plurality of non-cylindrical divided pieces, and a tightening mechanism that tightens the divided pieces so as not to be divided when the cylindrical member is attached to the outer periphery of the PC steel material.

The outer shape of the cylindrical member is not particularly limited, but is preferably cylindrical. Further, the outer diameter of the cylindrical member is not limited, but preferably, there is no great difference from the outer diameter of the members (eg, the grip 3 and the load cell 5 in FIG. 5) arranged so as to sandwich the cylindrical member, And when arrange | positioning to PC steel materials, it is made not to contact with PC steel materials adjacent to this PC steel material. Further, the inner diameter of the cylindrical member may be larger than the outer diameter of the PC steel material, but is preferably substantially matched with the outer diameter of the PC steel material. When the inner diameter of the cylindrical member and the outer diameter of the PC steel are almost the same, the cylindrical member is less likely to be displaced from the outer periphery of the PC steel, and the tension of the PC steel transmitted through the wedge / wedge holder that holds the PC steel Force can be transmitted to the bearing surface without loss.

  The number of the non-cylindrical divided pieces is not limited as long as they become cylindrical when combined. The number is preferably 2 to 4 in consideration of time and effort for combining. Moreover, each division | segmentation piece will not ask | require the shape, if it is formed so that the cross section (annular cross section) of a cylindrical member may be divided | segmented into the circumferential direction. For example, when the split pieces are combined into a cylindrical shape, the line representing the joint portion of the split pieces may be zigzag or straight. At this time, although the cross section perpendicular | vertical with respect to the end surface of each division | segmentation piece and the axial direction of a cylinder is circular, it is preferable that the central angle of all these arcs does not exceed 180 degrees. If the arc center angle exceeds 180 °, the PC steel must be pushed into the split piece and placed, which may damage the outer periphery of the PC steel.

  The shim of the present invention has a tightening mechanism for tightening each divided piece so as not to be divided into a plurality of divided pieces when the cylindrical member as described above is arranged on the PC steel material. Since the divided pieces are divided into non-cylindrical shapes, naturally, the tightening direction must be shifted from the axial direction. Examples of the tightening mechanism include a band disposed so as to cover the outer periphery of the cylindrical member and a screw that tightens the divided pieces together.

  As a band used for the tightening mechanism, a tie wrap (Thomas and Bets International, a registered trademark of Ink) may be used, or a metal ring partially opened may be used. If the ring is used, a flange portion is provided in the open portion of the ring, and the flange portion is tightened with a screw or the like to reduce the diameter of the ring, that is, the cylindrical member is radially inward. tighten.

  Moreover, when using the screw | tightening tightened so that each division | segmentation piece may be gathered, the hole which penetrates a screw | thread is provided in each division | segmentation piece. For example, when the cylindrical member is composed of two divided pieces, one divided piece is provided with a through hole (a screw hole with a screw or one without a screw), and a screw hole is provided in the other divided piece. For example. Then, the bolt is passed through the through hole of one of the divided pieces, and then screwed into the other screw hole, thereby tightening the two divided pieces in a direction approaching each other. At this time, the screw hole may be a screw hole penetrating the divided piece. Alternatively, through holes may be provided in the two divided pieces, bolts may be passed through the two through holes, and nuts may be disposed at the ends of the bolts and tightened.

  Regardless of which tightening mechanism is selected, it is preferable to provide a notch in each divided piece so that the tightening mechanism does not protrude from the outer periphery of the cylindrical member. Since there may be other PC steel materials adjacent to the PC steel with the shim on the outer periphery of the shim, if the tightening mechanism protrudes from the outer periphery of the shim, this tightening mechanism will damage other PC steel materials. May end up. Further, if the tightening mechanism protrudes from the outer periphery of the shim, it interferes with various operations in the fixing unit.

  The shape of the notch provided in the divided piece is not particularly limited. Preferably, a shape that does not hinder the work when the divided pieces are tightened by the tightening mechanism is selected. In particular, when a screw is used for the tightening mechanism, it is preferable to form a plane having a through hole through which the screw penetrates at right angles to the axial direction of the through hole. By doing in this way, when the divided piece is tightened with a screw, the screw head of the screw comes into surface contact with the divided piece, so that the force for tightening the divided piece by the screw can be easily adjusted. Of course, the screw head should not protrude from the outer periphery of the cylindrical member. When using a band, it is preferable to provide a notch (groove) capable of fitting the band on the outer periphery of the cylindrical member.

  Further, the present invention is a method of unloading the tension of the PC steel for loosening the tension introduced into the PC steel at the fixing portion of the PC steel in the PC structure and transmitted to the bearing surface of the PC structure. is there. The fixing portion includes a wedge that grips a strained PC steel material, a wedge receiver that has a fitting hole into which the wedge is fitted, and a shim that is disposed so as to cover the outer periphery of the PC steel material closer to the bearing surface than the wedge receiver. With. The shim is formed into a cylindrical shape by combining a plurality of non-cylindrical divided pieces, and is tightened so that the divided pieces are not divided by a tightening mechanism. And in the fixing part composed of these wedges, wedge receivers and shims, when unloading the tension, after tightening the PC steel again, loosen the tightening by the tightening mechanism and remove the shim from the outer periphery of the PC steel It is characterized by unloading the tension of the PC steel applied to the PC structure by removing it.

  The fixing part of the PC steel material in the PC structure has a wedge that holds the tensioned PC steel material and a wedge receiver that fits the wedge, and the tensile force introduced to the PC steel material is applied to the PC structure through these members. Is transmitted to the bearing surface. Here, by using the above-described shim of the present invention in addition to the wedge / wedge receiver, the tension force once introduced into the PC steel can be unloaded.

  When forming the fixing portion, the shim can be arranged at an arbitrary position on the bearing surface side with respect to the wedge receiver. The shim is formed by arranging each non-cylindrical divided piece so as to cover the outer periphery of the PC steel material and forming it into a cylindrical shape, and tightening each divided piece formed into a cylindrical shape by a tightening mechanism. After all the members in the fixing part are arranged, the PC steel material is tensioned and fixed by the wedge.

  When loosening the tension of the PC steel material, the PC steel material is tensioned again to remove the tightening mechanism that tightens the cylindrical member of the shim, and the shim is disassembled and removed from the outer periphery of the PC steel material. After removing the shim, loosen the re-tension of the PC steel. At this time, since the tension of the PC steel material is relaxed by the length of the shim in the axial direction, the tension of the fixing portion can be unloaded.

  According to the tension adjusting shim of the present invention, it is possible to provide a shim that can be easily attached to and detached from the outer periphery of a PC steel and that the shim is not divided when a tension is introduced into the PC steel. .

  Moreover, according to the method of unloading the tension of the PC steel material of the present invention, the tension force of the PC steel material once introduced into the fixing portion can be easily unloaded in units of individual PC steel materials.

<Example 1>
In the present embodiment, a method of providing a tension monitoring unit that monitors the tension of the PC steel in the fixing portion of the PC steel inside the bridge girder and unloading the tension acting on the tension monitoring unit will be described as an example. First, a method for forming a tension monitoring unit in the fixing unit, and then a method for unloading the tension force introduced into the tension monitoring unit, followed by each member constituting the monitoring unit, will be described with reference to the drawings. To do.

  As shown in FIG. 1, the tension monitoring unit 10 includes a wedge 2 for gripping the PC steel material 1, a grip 3 for inserting the wedge 2, a shim 40 according to the present invention, a load cell 5 for measuring tension, and a bearing pressure for aligning the load cell 5. A tension force is transmitted from the monitoring unit 10 to the bearing surface G via the anchor disk 8 and the rib cast anchor 9. At this time, a hole-filling ring 7 is disposed in the fitting hole 8Ha of the anchor disk 8, and the end surface of the anchor disk 8 with which the end surface of the bearing ring 6 abuts is flush with the tension of the PC steel material 1. Transmission is made without loss to the anchor disk 8. By doing so, the tension in the fixing portion formed by fitting the wedge 2b holding the PC steel material 1 into the fitting hole 8Hb of the anchor disk 8 is not provided, that is, the normal fixing portion without the monitoring portion 10. A substantially equal load can be applied to the monitoring unit 10. Therefore, the measurement result of the load cell 5 provided in the tension monitoring unit 10 can be regarded as the tension in the normal fixing unit.

  The wedge 2 is formed in a conical cylinder shape, can be fitted into a fitting hole 3H of a grip 3 (wedge receiver) described later, and the PC steel material 1 can be disposed therein. In addition, the wedge 2 was configured by joining three divided pieces having a circular cross section. By forming the wedge 2 into three divided pieces, the inner diameter can be changed within a predetermined range when the divided pieces are combined into a conical cylinder shape. Therefore, when the PC steel material 1 is disposed inside the wedge 2, the PC steel material 1 can be gripped by changing the inner diameter of the wedge 2 in the direction of shrinking.

  The grip 3 is a cylindrical member having a fitting hole 3H into which the wedge 2 can be fitted. The fitting hole 3H of the grip 3 is formed so that the front end portion of the wedge 2 protrudes from the grip 3 and does not interfere with the shim 40 contacting the grip 3 when the wedge 2 is fitted into the fitting hole 3H.

  As shown in FIG. 2, the shim 40 includes a cylindrical member formed by combining two divided pieces 41 and 42, and a screw (hexagon socket head bolt 46 that tightens the two divided pieces 41 and 42 so as to join them. ). The outer diameter of the cylindrical member was formed approximately equal to the outer diameter of the grip 3 (see FIG. 1). Further, a concave portion 48 into which a load cell described later is fitted is formed on one end surface of the cylindrical member. By doing in this way, the tension force of the PC steel material 1 transmitted from the grip 3 can be transmitted to the load cell 5 without loss (see FIG. 1). Further, the inner diameter of the cylindrical member was formed to be substantially equal to the outer diameter of the PC steel material (slightly larger than the outer diameter of the PC steel material). By doing so, the inner peripheral surface of the cylindrical member damages the outer peripheral surface of the PC steel material, or a gap is increased between the inner peripheral surface of the cylindrical member and the outer peripheral surface of the PC steel material. The center of PC and the center of PC steel can be prevented from shifting. In particular, if the center of the shim 40 and the PC steel material are misaligned, the pressure applied to the shim 40 becomes non-uniform in the circumferential direction of the shim 40, so the shim 40 is damaged and the tension of the PC steel material is transmitted to the load cell without loss. Because you can't do it, you can't monitor your tension properly.

  The split piece 41 is provided with a notch 43 and a through hole 44 that is formed continuously from the notch 43 and through which the bolt 46 passes. Two notches 43 are provided at the upper part and two at the lower part of the split piece 41 so that the head of the bolt 46 does not protrude. Further, the notch 43 is formed so that the surface 43a of the notch 43 provided with the through hole 44 is orthogonal to the axial direction of the through hole 44, so that the bolt 46 can be easily tightened. Further, the diameter of the through hole 44 was formed larger than the outer diameter of the bolt 46. Of course, the through hole 44 may be a screw hole in which a screw groove is cut so that the bolt 46 can be screwed together.

  On the other hand, when the split piece 42 is formed in a cylindrical shape in combination with the split piece 41, a screw hole 45 is provided at a position corresponding to the through hole 43 of the split piece 41. By doing so, when the bolt 46 is passed through the through hole 43 of the split piece 41, the end of the bolt 46 is screwed into the screw hole 45 of the split piece 42, so that the split pieces 41 and 42 are brought closer to each other. It can be tightened in the direction. The screw hole 45 may be a screw hole that penetrates the split piece 42.

  A commercially available load cell was used. As shown in FIG. 1, the load cell 5 is a member formed in a cylindrical shape, and the PC steel material 1 can be inserted through the inner peripheral surface thereof. A plurality of sensing units (not shown) are equally arranged in the circumferential direction on the cylindrical end surface, and a load applied to the sensing units is measured as a change in voltage.

  The support ring 6 is a cylindrical member. The bearing ring 6 has a large diameter portion and a small diameter portion each having a constant outer diameter. The outer diameter of the large diameter portion matches the outer diameter of the load cell 5 described above, and anchors the pressure from the load cell 5 without loss. Transmit to disk 8. On the other hand, the small-diameter portion is formed to be larger than the diameter of the end portion of the hole filling ring 7 described later, that is, larger than the diameter of the fitting hole 8Ha of the anchor disk 8. By doing so, it is possible to prevent the bearing ring 6 from pressing only the hole-filling ring 7 and losing the tension of the PC steel material 1 to be transmitted to the anchor disk 8.

  The hole-filling ring 7 is a conical cylindrical member, and the PC steel material 1 can be disposed therein. Then, when the PC steel material 1 was placed inside and fitted into the fitting hole 8Ha of the anchor disk 8, the end face on the large diameter side was formed to be flush with the end face of the anchor disk 8. By doing so, the entire end face of the above-mentioned bearing ring 6 comes into surface contact with the surface formed by the end face of the anchor disk 8 and the end face of the hole-filling ring 7. Can be transmitted to the bearing surface G without loss.

In the tension monitoring unit 10 constituted by these members, when the tension applied to the monitoring unit 10 is unloaded, the PC steel material 1 is tensioned again. By tensioning the PC steel material 1, the grip 3 does not press the shim 40, so that the shim can be removed. As shown in FIG. 2, the shim 40 is removed by loosening the hexagon socket head cap screw 46 and removing it from the divided pieces 41 and 42, and removing the divided pieces 41 and 42 from the outer periphery of the PC steel material. At this time, since the split pieces 41 and 42 are engaged only by the bolts 46, the tension of the PC steel material can be easily unloaded simply by releasing the tightening of the bolts 46 and removing the bolts from the split pieces 41 and 42. be able to.

  In this example, the fixing portion of the PC steel material provided with the tension monitoring unit is described as an example. However, the tension adjusting shim of the present invention is not limited to being provided in the tension monitoring unit. For example, the present invention can be suitably used for a temporary fixing reinforcing wire that is tensioned only during the operation of installing the reinforcing wire on the main line of the bridge. In this case, a temporary fixing line is connected in the middle of the main line, and the shim of the present invention is used for a fixing portion of the temporary fixing line. When the reinforcement line is installed on the main line, the shim is disassembled at the fixing portion of the temporary fixing line, the tension of the temporary fixing line is unloaded, and the temporary fixing line is removed.

<Modification 1-1>
Next, a configuration for fastening the divided pieces constituting the shim with screws (bolts) and nuts is described. In this example, since the method of unloading the tension force introduced into the members other than the shim and the PC structure is the same as that in the first embodiment, the description thereof is omitted. Hereinafter, the structure of the shim of this example will be described with reference to FIG.

  As shown in FIG. 3, the shim 50 of this example was formed by combining two divided pieces 51 and 52 into a cylindrical shape and tightening them with a hexagon socket head cap screw 56 and a nut 57. Here, the divided pieces 51 and 52 are the same member in which the positions and shapes of the notches and the through holes are exactly the same.

  When attaching the shim 50, first, the split pieces 51 and 52 are combined to form a cylindrical shape, and a hexagon socket head cap screw 56 is inserted into the through hole 54 of the split piece 51 from the direction of the notch 53 of the split piece 51. . Subsequently, the end portion of the bolt 56 was inserted into the through hole 55 of the split piece 52 so that the end portion of the bolt 56 protruded from the through hole 55 of the split piece 52. Then, a nut 57 was screwed into the protruding end portion of the bolt 56, and the divided pieces 51 and 52 were tightened. At this time, not only the head of the bolt 56 but also the nut 57 was arranged in the space formed by the notch 53 and did not protrude to the outer periphery of the shim 50. The engagement of the recess 58 with the end of the load cell is the same as in the first embodiment.

  According to the configuration of this example, it is only necessary to prepare one mold when producing the divided pieces, which is economical. Moreover, the trouble of forming a screw groove in the through hole formed in the divided piece can be saved.

<Modification 1-2>
Next, a description will be given of the shim of the present invention in which a shim formed into a cylindrical shape by combining divided pieces is tightened from the outer peripheral side with a tightening band (Tie Wrap: registered trademark). Since the method of unloading the tension force introduced to the members other than the shim and the PC structure is the same as that of the first embodiment, the description thereof is omitted. Hereinafter, the structure of the shim of this example will be described with reference to FIG.

  As shown in FIG. 4, the shim 60 of this example is formed by fastening two divided pieces 61 and 62 into a cylindrical shape and fastening them with a fastening band 66. Here, the divided pieces 61 and 62 are the same member in which the positions and shapes of the notches (grooves) are exactly the same.

  When the shim 60 was formed, first, the divided pieces 61 and 62 were combined to form a cylindrical shape, and a fastening band 66 was wound around an annular groove 63 formed over the entire circumference of the cylinder. The fastening band 66 is provided with a fixing member 66a for stopping the band at its end, and this fixing member 66a engages with the unevenness formed on the surface of the band when the end 66b of the band is inserted. It is formed so that the tightening does not loosen easily. Accordingly, when the end portion 66b of the band 66 is inserted through the fixing member 66a and pulled, the inner diameter of the circle formed by the band 66 is reduced, so that the divided pieces 61 and 62 are tightened as shown in FIG. be able to. At this time, the fastening band 66 is housed in the annular groove 63 and does not protrude from the outer periphery of the shim 60. The engagement of the recess 68 with the end of the load cell is the same as in the first embodiment.

  According to the structure of this modification, since it does not have complicated shapes, such as a through-hole, a division | segmentation piece can be manufactured only by preparing one metal mold | die of a very simple shape.

  The shim of the present invention can be suitably used for a fixing portion of a PC steel that needs to adjust the tension introduced into the PC steel for each PC steel.

FIG. 1 is a schematic explanatory view of a fixing portion of a PC steel material in the PC structure described in the first embodiment. 2A and 2B are diagrams showing the shim described in the first embodiment. FIG. 2A is a front view, and FIG. 2B is a cross-sectional view taken along line A-A ′. 3A and 3B are diagrams showing a shim described in Example 1-1, where FIG. 3A is a front view and FIG. 3B is a B-B ′ cross section. 4A and 4B are diagrams showing a shim described in Example 1-2, in which FIG. 4A shows a front view and FIG. 4B shows a C-C ′ cross section. FIG. 5 is a schematic explanatory view showing a fixing portion of a PC steel material in a conventional PC structure.

Explanation of symbols

1 PC steel 2 Wedge 3 Grip 4 Shim 5 Load cell
6 Bearing ring 7 Filling ring 8 Anchor disc
8H Mating hole 9 Rib cast anchor 10 Tension monitor
2A Wedge 8Ha Mating hole 2b Wedge 3H Mating hole
40 Sim
41,42 Dividing piece 43 Notch 44 Through hole 45 Screw hole
46 Hexagon socket head cap screw 48 Recess
50 Sim
51,52 Divided piece 53 Notch 54,55 Through hole
56 Hexagon socket head cap screw 57 Nut 58 Recess
60 Sim
61,62 Split piece 63 Annular groove 68 Recess
66 Tightening band 66a Fixing member 66b End

Claims (6)

A tension adjusting shim disposed on the outer periphery of the PC steel to adjust the tension of the tensioned PC steel,
The shim is
A cylindrical member formed by combining a plurality of non-cylindrical divided pieces;
A tension adjusting shim, comprising: a tightening mechanism for tightening the split pieces so as not to be split when the cylindrical member is attached to the outer periphery of the PC steel material. The said tension | tensile_strength adjustment shim is provided between the wedge receptacle which inserts the wedge holding the tension | tensile_strength PC steel material, and the load cell which monitors the tension | tensile_strength of PC steel material, It is characterized by the above-mentioned. Shim for adjusting tension. Tension adjusting shim according to claim 1 or 2, wherein the clamping mechanism is a screw. The tension adjusting shim according to claim 1 or 2, wherein the tightening mechanism is a tightening band for tightening the divided piece from the outer peripheral side. The tension adjusting shim according to claim 3 or 4 , wherein a notch is provided in an outer peripheral portion of the split piece so that the tightening mechanism does not protrude from the outer periphery of the cylindrical member. In the fixing unit of the PC steel material in the PC structure is introduced into the PC steel, a method of unloading a tension force transmitted to the bearing capacity surfaces of the PC structure,
The fixing unit is
A wedge that grips the strained PC steel,
A wedge receiver having a fitting hole for fitting the wedge;
On the bearing surface side than the wedge receiver, comprising a cylindrical shim arranged to cover the outer periphery of the PC steel material,
The shim is formed into a cylindrical shape by combining a plurality of non-cylindrical divided pieces, and is tightened so that each divided piece is not divided by a tightening mechanism,
In the fixing part composed of these wedges, wedge receivers, and shims, when unloading the tension, the PC steel is re-tensioned and then tightened by the tightening mechanism to remove the shims and apply to the PC structure. Unloading the tension of PC steel, characterized by unloading the applied tension.

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