Apparatus and method for tensioning and fastening a plurality of prestressing tendons

Abstract

To reduce a tension difference between a plurality of PC steel materials when the PC steel materials are tensioned.SOLUTION: A tension anchorage device 1000 is composed of: a jack 1600 provided with a piston 1610 for tension and a lock-off piston 1620 for press-fit; a reaction plate 1310 which receives a force from the piston 1610 for tension and acts on a plurality of anchorage devices 1100 for tension in common; the plurality of anchorage devices 1100 for tension provided on the reaction plate 1310; an anchorage plate 1300 which is brought into contact with the end face of the structure 100; a plurality of anchorage devices 1200 for fixing provided on the anchorage plate 1300; a press-fit plate 1500 which receives a force from the lock-off piston 1620 for press-fit and acts on a plurality of wedges 1210 in common; a chair 1400 for tension anchorage which is brought into contact with the end face on the open end side of the anchorage plate 1300 and a nose 1630 of the jack 1600.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present invention relates to a prestressing steel tensioning and fixing device and a prestressing steel tensioning and fixing method that apply compressive force (prestress) to structures such as concrete structures in the architectural field or building components other than concrete (such as wood) by placing prestressing steel members and tensioning the prestressing steel members using a post-tensioning method.In particular, the present invention relates to a technology that can reduce the tension difference between prestressing steel members and apply compressive force as evenly as possible to a structure when multiple prestressing steel members are tensioned by one-sided or double-sided tensioning.

[0002] In the present invention, the term "PC steel material" (sometimes referred to as "steel material for PC") includes PC steel wires, PC steel bars, PC steel strands (PC steel strands), and PC steel materials whose outer surfaces are coated with resin (such as epoxy), including irregular types thereof. In the following description, the fixing device (fixing body, grip) that clamps (fixes) the PC steel wires by its frictional force is a combination of a male wedge (sometimes referred to as a wedge body, wedge, wedge, male cone, etc.) and a female sleeve (sometimes referred to as a female cone, etc.) to fix the PC steel material in a tensioned state. Some wedges are divided into multiple wedge pieces (two (half), three or more) when viewed from a plane perpendicular to the axial direction of the PC steel material, and in the following description, "multiple wedges" means that there are multiple wedges each consisting of a combination of two (two-piece) or three (three-piece) wedge pieces. Therefore, if there are four wedges, if they are divided into two (halves), there will be eight wedge pieces, and there are four wedges in which two wedge pieces are combined together to function as one wedge. [Background technology]

[0003] The anchoring portion (anchor, anchoring tool, grip) of the PC steel member is configured to grip the PC steel member with an anchoring wedge and transmit the tension of the tensioned PC steel member to the structure (typically concrete). The anchoring wedge grips the PC steel member by being pushed into the hole of the wedge receiving member. Tension anchoring devices that use multiple PC steel members for one structure are also known.

[0004] When pushing a wedge into a single structure using a jack including a tensioning anchoring device that uses multiple PC steel members, the wedge cannot be pushed into the wedge receiving member (hole) with a force greater than the tension load when the PC steel members are tensioned.In light of this problem, in a tensioning anchoring process that uses multiple PC steel members for a single structure, JP 2011-252323 A (Patent Document 1) discloses a tensioning anchoring device with a simple configuration that can push in a wedge with a force greater than the tension load applied to the PC steel members. The wedge pushing device disclosed in Patent Document 1 is a wedge pushing device for pushing a wedge holding each of a plurality of PC steel members into a hole in a wedge receiving member through which each of the PC steel members passes, and has a tensioning jack that applies tension to the plurality of PC steel members and generates a force to push the wedge into the hole, and the tensioning jack pushes the wedge into the hole while each of the plurality of PC steel members is tensioned with a first tension, and uses the reaction force generated when a second tension force smaller than the first tension force is applied to a first PC steel member among the plurality of PC steel members to push the wedge corresponding to a second PC steel member different from the first PC steel member back into the hole (Claim 5).

[0005] The wedge pushing-in device disclosed in Patent Document 1 can generate a force to push in a wedge corresponding to a second prestressing tendon different from the first prestressing tendon by using the reaction force of the second tension applied to the first prestressing tendon. This eliminates the need for a dedicated member for pushing in the wedge. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] JP 2011-252323 A Summary of the Invention [Problem to be solved by the invention]

[0007] However, in the wedge pushing technique disclosed in Patent Document 1, when multiple PC tendons are used for tensioning and fixing a single structure, a tensioning jack is used that applies tension to the multiple PC tendons and generates a force to push the wedge into the hole (used for both tensioning and pressing), and does not use a jack that is suitable and commonly used for tensioning and fixing center-hole type PC tendons that has a lock-off piston for pressing in the wedge in addition to a tensioning piston. Furthermore, the first PC tendon and the second PC tendon that is different from the first PC tendon are tensioned separately, and the wedges are pushed in separately. The force that pushes in the wedge is generated by the reaction force when the tensioning jack tensions the other PC tendons. Therefore, the following problems exist.

[0008] [Challenge 1] In Patent Document 1, multiple anchors are used for multiple PC steel members arranged in one structure, but they are not tensioned simultaneously, nor are wedges pressed in simultaneously, making it difficult to introduce uniform tension force to the multiple PC steel members. [Task 2] In Patent Document 1, multiple anchors are used for multiple prestressing tendons arranged for one structure, but the force with which the wedge is pushed in is generated by the reaction force when the tensioning jack tensions other prestressing tendons (i.e., the combination of the prestressing tendons to be tensioned and the prestressing tendons to be pushed in by the wedge changes sequentially.) For this reason, it is impossible to press in the wedge uniformly, and differences arise in the amount of wedge penetration between the prestressing tendons when they are fixed, making it difficult to introduce tension uniformly. [Challenge 3] As with problem 2, in Patent Document 1, it is impossible to press the wedges evenly, so that there is a possibility that a step will occur between each wedge that is fixed to the PC steel material when the wedges are fixed, which may cause slippage.

[0009] [Challenge 4] In relation to the problem 1, in Patent Document 1, the PC tendons are not tensioned at the same time, and the wedges are not pressed in at the same time, and the combination of the PC tendons to be tensioned and the PC tendons to be pressed in with the wedges is changed sequentially. The wedge of the already tensioned first PC tendon is pressed in by the reaction force when the second PC tendon is tensioned, and the wedge of the second PC tendon is pressed in by the reaction force when the third PC tendon is tensioned, and this process is repeated sequentially. It is clear that there is a slight difference in the tension force tensioning the PC tendons between the PC tendons, which means that there is also a slight difference in the wedge pressing force using the reaction force. In this way, it is unavoidable that there is a slight difference in the tension force tensioning the PC tendons and the force to press in (press in) the wedge of another PC tendon using that reaction force, and there may be cases where it is somewhat difficult to introduce tension force uniformly into a structure.

[0010] [Challenge 5] Furthermore, whether the tension anchoring method uses one (single) prestressing tendon for one structure or multiple (multiple) prestressing tendons for one structure (multiple cases are more problematic due to the large number of wedges), there is a possibility that the wedge will fall out of the wedge receiving member (hole), including when the prestressing tendons are tensioned before the wedge is pressed in. If this happens, it will be impossible to press the wedge into the wedge receiving member (hole).

[0011] The present invention was developed in consideration of the above-mentioned problems of the prior art, and its purpose is to provide a device and method for tensioning and fixing multiple PC steel members which, when tensioning and fixing multiple PC steel members that apply compressive force to a structure using tensioning fixtures and fixing fixtures composed of wedges and sleeves, can reduce the tension difference between multiple PC steel members and apply compressive force to a structure as evenly as possible.

[0012] Furthermore, an object of the present invention is to provide a device and method for tensioning and fixing multiple PC steel members that can reduce the possibility of the wedge falling off the wedge receiving member (hole), including when the PC steel members are tensioned before the wedge pressing-in operation, when the multiple PC steel members that apply compressive force to a structure are tensioned and fixed using a tensioning fixture and a fixing fixture consisting of a wedge and a sleeve. [Means for solving the problem]

[0013] In order to achieve the above object, the device for tensioning and fixing a plurality of PC tendons and the method for tensioning and fixing a plurality of PC tendons according to the present invention comprise the following technical means. That is, a tensioning and fixing device for a plurality of prestressing steel members according to one aspect of the present invention is a tensioning and fixing device for a plurality of prestressing steel members that apply a compressive force to a structure, which tensions and fixes the plurality of prestressing steel members by using a tensioning fixing device and a fixing fixing device composed of wedges and sleeves, and in the tensioning fixing device and the fixing fixing device, a plurality of wedges that bite into and hold each of the plurality of prestressing steel members at their inner peripheries are fixed such that the tapered surfaces of the outer peripheries of the wedges abut against the tapered surfaces of the inner peripheries of a plurality of sleeves through which each of the prestressing steel members passes, and the tensioning and fixing devices are common to a jack provided on the open end side of the prestressing steel members and equipped with a tensioning piston and a press-in lock-off piston, and a plurality of tensioning fixing devices provided on the open end side of the jack so as to receive a force from the tensioning piston that operates in a direction to stretch the prestressing steel members the tensioning anchoring device includes a reaction plate acting on the wedges, a plurality of tensioning anchors provided on the open end side of the reaction plate and fixing each of the PC steel members, an anchoring plate abutting the end face of the open end side of the structure, a plurality of fixing anchoring devices in the same number as the PC steel members, each of which has a sleeve fixed thereto so as to abut against the end face of the open end side of the anchoring plate and fixes each of the PC steel members, a press-in plate acting commonly on the wedges and provided to receive force from a press-in lock-off piston which operates in a direction to press the end faces of the open end side of the wedges of the fixing anchoring device toward the sleeve, and which presses the end faces of the open end side of the multiple wedges of the fixing anchoring device, and a tensioning anchoring chair which abuts against the end face of the open end side of the anchoring plate and the nose of the jack, and which has a through hole through which the press-in lock-off piston passes.

[0014] Preferably, the length of the PC steel in the tensioning chair in the longitudinal direction can be configured to be at least longer than the sum of the length of the fixing fixture in the longitudinal direction and the length of the press-in plate. More specifically, with respect to the length of the PC steel in the longitudinal direction, the leg length of the tensioning chair can be configured to be at least longer than the sum of the length of the fixing fixture (including the length of the wedge expansion side protruding before tensioning) and the length of the press-in plate (the thickness of the plane pressed by the press-in lock-off piston).

[0015] More preferably, the tensioning anchoring device can be configured to further include a fall prevention mechanism that prevents the wedge of the fixing anchoring device from falling out of the sleeve of the fixing anchoring device during tensioning when the PC steel material is being stretched by the tensioning piston. More preferably, the press-in plate is connected to the fixing fixture so as to be freely movable in the longitudinal direction of the PC steel, and has a substantially flat portion having a hole for inserting the PC steel and a hole for inserting a connecting member connected to the fixing fixture, and the fall prevention mechanism can be configured to prevent the press-in plate from falling out of the sleeve by abutting the end face on the open end side of the wedge during the tensioning.

[0016] More preferably, the tensioning fixing device further includes a substantially flat wedge holder between the press-in plate and the fixing fixing device, connected to the fixing fixing device so as to be freely movable in the longitudinal direction of the PC steel, and having a hole for inserting the PC steel and a hole for inserting a connecting member connected to the fixing fixing device, and the fall prevention mechanism can be configured to prevent the wedge holder, which is separate from the press-in plate, from falling out of the sleeve during tensioning by abutting against the end face on the open end side of the wedge.

[0017] A method for tensioning and fixing a plurality of prestressing steel members according to another aspect of the present invention is a method for tensioning and fixing a plurality of prestressing steel members that apply a compressive force to a structure, using a tensioning fixture and a fixing fixture composed of a wedge and a sleeve, in which a plurality of wedges that bite into and hold each of the plurality of prestressing steel members at their inner peripheries are fixed in the tensioning fixture and the fixing fixture by abutting tapered surfaces on the outer peripheries of the wedges against tapered surfaces on the inner peripheries of a plurality of sleeves through which each of the prestressing steel members passes, and the method for tensioning and fixing a plurality of prestressing steel members of the structure is performed by using a tensioning fixture and a fixing fixture composed of a wedge and a sleeve. the step of providing a fixing plate so as to abut against an end face of the open end of the fixing plate; the step of providing a plurality of fixing fixtures for fixing each of the PC steel members on the fixing plate so as to abut against an end face of the open end of the fixing plate on the open end; the step of providing a jack having a tensioning piston and a press-in lock-off piston on the open end side of the PC steel; and the step of applying a pressure force acting commonly on the plurality of wedges to press the end faces of the open end of the plurality of wedges in response to a force from a press-in lock-off piston that operates in a direction to press the end faces of the open end of the wedges of the fixing fixture. the step of providing an insertion plate; the step of providing a tensioning anchoring chair having a through hole through which the press-fitting lock-off piston passes so as to abut against the end face of the open end side of the anchoring plate and the nose of the jack; the step of providing a reaction plate on the open end side of the jack that receives the force from the tensioning piston that operates in the direction of stretching the PC steel and acts commonly on a plurality of tensioning anchors; the step of providing a plurality of tensioning anchors on the open end side of the reaction plate to fix each of the PC steels; a step of operating a tensioning piston of a jack and tensioning the plurality of PC steel members by applying a predetermined load using the reaction plate and the tensioning fixture; a step of operating the press-in lock-off piston while the predetermined load is applied and using the press-in plate to press the end faces on the open end sides of the wedges of the plurality of fixing fixtures to press the wedges into the sleeves of the fixing fixtures; and a step of releasing the predetermined load after pressing the wedges into the sleeves of the fixing fixtures and removing everything other than the fixing plate and the fixing fixtures.and cutting the prestressing tendons while leaving a necessary slack length. Effect of the Invention

[0018] According to the device and method for tensioning and fixing multiple PC steel members of the present invention, when multiple PC steel members that apply compressive force to a structure are tensioned and fixed using tensioning fixtures and fixing fixtures composed of wedges and sleeves, the tension difference between the multiple PC steel members can be reduced and the compressive force can be applied to the structure as evenly as possible.

[0019] In addition, according to the device and method for tensioning and fixing multiple PC steel members of the present invention, when multiple PC steel members that apply compressive force to a structure are tensioned and fixed using a tensioning fixture and a fixing fixture consisting of a wedge and a sleeve, the possibility of the wedge falling off the wedge receiving member (hole) can be reduced, including when the PC steel members are tensioned before the wedge pressing-in operation. [Brief description of the drawings]

[0020] [Figure 1] This is a diagram showing the arrangement of PC steel members in a plane perpendicular to the axial direction of the PC steel members in a structure (concrete member, wood) to which a compressive force (prestress) is applied by applying a tensioning anchoring device for multiple PC steel members (hereinafter sometimes simply referred to as a tensioning anchoring device) according to an embodiment of the present invention (common to the first and second embodiments). [Diagram 2] FIG. 1 is a three-sided view of a tension fixing chair 1400 constituting a tension fixing device according to an embodiment of the present invention (common to the first and second embodiments). [Diagram 3] 3A is a three-sided view of a press-fitting plate 1500 constituting the tension fixing device according to the first embodiment of the present invention, and FIG. 3B is a cross-sectional view taken along the arrow 3B in FIG. 3A. [Figure 4] 1 is a side view of a tensioning and fixing device according to an embodiment of the present invention (common to the first and second embodiments) before it is installed (sometimes referred to as set). FIG. [Diagram 5] 5A is a side view of a tensioning anchoring device 1000 according to a first embodiment of the present invention disposed on a PC steel member 200, and FIG. 5B is an enlarged view of an area 5B in FIG. 5A. [Figure 6] 5. (A) is a view seen from the arrow 6A in FIG. 5, and (B) is a view seen from the arrow 6B in FIG. [Figure 7] FIG. 6 is a side view for explaining a step of tensioning a PC steel member in a tensioning method using the tensioning anchoring device 1000 shown in FIG. 5. [Figure 8] 6 is a side view for explaining a step of pressing in a wedge in the tension fixing method using the tension fixing device 1000 shown in FIG. 5. FIG. [Figure 9] 9A and 9B are views for explaining a state before and during press-fitting in the step of press-fitting the wedge shown in FIG. 8. [Figure 10] 10A is a three-sided view of a press-fit plate 2500 constituting a tensioning anchoring device 2000 according to a second embodiment of the present invention, and FIG. 10B is a cross-sectional view taken along the line indicated by arrow 10B in FIG. 10A. [Figure 11] 11A and 11B are two-sided views of a tensioning and anchoring device 2000 according to a second embodiment of the present invention. [Figure 12] 12(A) is a side view of a tensioning anchoring device 2000 according to a second embodiment of the present invention arranged on a PC steel member 200, (B) is an enlarged view of region 12B in FIG. 12(A), and (C) is an enlarged view of region 12C in FIG. 12(B). [Figure 13] 12. (A) is a view seen from an arrow 13A in FIG. 12, (B) is a view seen from an arrow 13B in FIG. 12, and (C) is a view seen from an arrow 13C in FIG. [Figure 14] 13 is a side view for explaining the step of tensioning the PC steel member in the tensioning fixing method using the tensioning fixing device 2000 shown in FIG. 12. FIG. [Figure 15]13 is a side view for explaining a step of pressing in a wedge in the tension fixing method using the tension fixing device 2000 shown in FIG. 12. FIG. [Figure 16] 16A and 16B are views for explaining a state before and during press-fitting in the step of press-fitting the wedge shown in FIG. 15. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] The following provides a detailed description of an embodiment of the present invention, including a tensioning and fixing device for multiple PC steel members (which may be simply referred to as a tensioning and fixing device, as described above) that tensions and fixes multiple PC steel members that apply compressive force to a structure using tensioning fixing devices and fixing fixing devices composed of wedges and sleeves, and a tensioning and fixing method using the tensioning and fixing device for multiple PC steel members (which may be simply referred to as a tensioning and fixing method).

[0022] In the drawings referred to in the following description, in order to facilitate understanding of the present invention, some parts that should be shown in their outer shapes rather than their inner shapes are shown as if they are seen through, some parts that should be shown in their cross sections rather than their outer shapes are shown in their outer shapes, some parts that should be shown in their outer shapes rather than their cross sections are shown in their cross sections, some cross sections are not hatched, some non-cross sections are hatched, some detailed structures are omitted, and some drawings of the same components do not match because detailed structures have been omitted or changed. Also, some outlines overlap (even though one should be shown as a hidden line), and some break lines are not shown.

[0023] First embodiment First, the characteristic structure of the tensioning and fastening device 1000 for multiple PC tendons according to the first embodiment of the present invention will be described in detail with reference to Figures 1 to 9, and then a method for tensioning and fastening multiple PC tendons using the tensioning and fastening device 1000 having this technical structure will be described in detail. Here, the open end side in the axial direction of the PC tendons may be simply referred to as the open end side.

[0024] 1, 2 and 4 are common to the first and second embodiments. In addition, in the tensioning and fastening device 1000 according to the first embodiment and the tensioning and fastening device 2000 according to the second embodiment, the press-fit plate (the press-fit plate 1500 in the first embodiment and the connecting bolt 1550 connecting the press-fit plate 1500 to the sleeve 1220 of the fixing fixture 1200, the third embodiment) is different from the press-fit plate 1500 in the first embodiment. The difference is that the structure of the press-fit plate 2500 (connecting bolt 2550 connecting the press-fit plate 2500 to the sleeve 1220 of the fixing fixture 1200) in the first and second embodiments is different in detail, and that the tensioning and fixing device 2000 includes a wedge pressing member 2800 that the tensioning and fixing device 1000 does not include. The same reference numerals are used for other structures that are the same in the first and second embodiments. The explanations of those structures in the second embodiment overlap with the explanations of the first embodiment, so they will not be repeated in the second embodiment. Furthermore, the explanations common to the tensioning and fixing method using the tensioning and fixing device 1000 according to the first embodiment and the tensioning and fixing method using the tensioning and fixing device 2000 according to the second embodiment will not be repeated in the second embodiment, because they overlap with the explanations of the first embodiment.

[0025] <Tension fixing device: structure> 1 to 6, in this tensioning fixing device 1000, in the tensioning fixing tool 1100 and the fixing fixing tool 1200, a plurality of wedges 1110 and 1210 that bite and hold a plurality of PC steel members 200 at their inner peripheries are fixed by abutting tapered surfaces of the outer peripheries of the wedges 1110 and 1210 against tapered surfaces of the inner peripheries of a plurality of sleeves 1120 and 1220 through which the PC steel members 200 pass. Specifically, as shown in Fig. 5(A) for the fixing fixing tool 1200, an outer periphery 1212 of the wedge 1210 (wedge outer periphery forms a tapered surface) that bites and holds the PC steel members 200 at its inner periphery is abutted against an inner periphery 1222 of the sleeve 1220 (sleeve inner periphery forms a tapered surface) and fixed.

[0026] This tensioning anchoring device 1000 includes a jack 1600 provided on the open end side of the PC steel 200 and equipped with a tensioning piston 1610 and a press-fit lock-off piston 1620, a reaction plate 1310 that acts in common on multiple tensioning anchors 1100 and is provided on the open end side of the jack 1600 so as to receive force from the tensioning piston 1610 which operates in a direction to stretch the PC steel 200, multiple tensioning anchors 1100 that are provided on the open end side of the reaction plate 1310 and secure each PC steel 200, an anchoring plate 1300 that abuts against the end face on the open end side of the structure 100, and a sleeve 1220 that abuts against the end face on the open end side of the anchoring plate 1300. the press-fitting lock-off piston 1620 which operates in a direction to press the open end face of the wedge 1210 of the fixing fixture 1200 toward the sleeve 1220, and acts commonly on the multiple wedges 1210, and presses the open end face of the multiple wedges 1210 of the fixing fixture 1200; and a tension fixing chair 1400 which abuts against the open end face of the fixing plate 1300 and the nose 1630 of the jack 1600, and which has a through hole 1430 through which the press-fitting lock-off piston 1620 passes.

[0027] 9, in the tensioning and fixing device 1000, the length L(1) of the PC steel 200 in the tensioning and fixing chair 1400 in the longitudinal direction is at least longer than the sum of the length L(2) of the fixing fixture 1200 in the longitudinal direction and the length L(3) of the press-fit plate 1500. More specifically, regarding the longitudinal length of the PC steel 200, the length L(1) of the leg 1410 in the tensioning and fixing chair 1400 can be configured to be at least longer than the sum of the length L(2) of the fixing fixture 1200 (including the length of the expansion side of the wedge 1210 before tensioning) and the length L(3) of the press-fit plate 1500 (the thickness of the flat portion 1510 pressed by the press-fit lock-off piston 1620).

[0028] More preferably, the tensioning anchoring device 1000 further includes a fall prevention mechanism that prevents the wedge 1210 of the fixing anchoring device 1200 from falling off the sleeve 1220 of the fixing anchoring device 1200 during tensioning when the PC steel material 200 is being stretched by the tensioning piston 1610. Here, it is also preferable that the press-in plate 1500 functions as a fall prevention mechanism. The press-in plate 1500 is connected to the fixing fixture 1200 so as to be movable in the longitudinal direction of the PC steel member 200, and has a hole 1530 through which the PC steel member 200 is inserted and a connecting member connected to the fixing fixture 1200. The above-mentioned fall prevention mechanism prevents the press-fit plate 1500 from falling out of the sleeve 1220 when tensioned by abutting against the end face on the open end side of the wedge 1210. Here, "inserted" or "inserted state" refers to a relationship in which the diameter of the hole provided in the member is larger than the diameter of a rod-shaped member or the like to be inserted into the hole, and the rod-shaped member or the like can pass through the hole freely.

[0029] The structure of the tensioning and fixing device 1000 according to this embodiment will be described in more detail below. Before further explaining the structure of the tension anchoring device 1000, an example of the arrangement of the PC steel 200 in the structure 100 will be described with reference to Fig. 1, which shows the arrangement of the PC steel 200 in a plane perpendicular to the axial direction of the structure 100 (concrete member, wood, etc.) to which the tension anchoring device 1000 is applied and a compressive force (prestress) is applied. Here, Figs. 1(A) and 1(B) show the shape of the structure and the anchoring plate provided on its end face, which is approximately square when viewed perpendicular to the axial direction of the PC steel 200, and Figs. 1(C) and 1(D) show the shape of the structure and the anchoring plate, which is approximately rectangular (approximately oblong). Note that in both figures, the wedge 1210 of the fixing fixture 1200 is shown, but the sleeve 1220 (described later) is not shown.

[0030] As shown in Fig. 1(A), a substantially square anchoring plate 1300 is provided on a structure 100 whose end face has a substantially square shape, and four PC steel members 200 are fixed at 90 degree intervals on a circumference centered on center 1302 of this anchoring plate 1300 by wedges 1210 (and sleeves 1220, not shown in this figure). The arrangement of the PC steel members 200 shown in Fig. 1(B) is at 90 degree intervals like the arrangement shown in Fig. 1(A), but the positions are different.

[0031] 1(C), a substantially rectangular anchoring plate 1301 is provided on the structure 102, whose end face has a substantially rectangular shape, and four PC steel members 200 are fixed by wedges 1210 (and sleeves 1220, not shown in this figure) so as to be symmetrical (line symmetry and point symmetry: the axis of symmetry and the center of symmetry are shown) with respect to this anchoring plate 1301. The arrangement of the PC steel members 200 shown in Fig. 1(D) is symmetrical (line symmetry and point symmetry) like the arrangement shown in Fig. 1(C), but two PC steel members 200 in each position, totaling eight, are fixed by wedges 1210 (and sleeves, not shown). Here, the wedge 1210 and the sleeve corresponding to this wedge 1210 shown in Figure 1 (D) have the same shape as the wedge 1210 and the sleeve corresponding to this wedge 1210 shown in Figures 1 (A) to 1 (C), and are arranged in pairs (each pair consisting of a wedge and a sleeve) side by side (a total of eight pairs) as shown in Figure 1 (D).

[0032] In the case of a tensioning anchoring device for multiple PC tendons, "multiple" refers to four tendons in the cases shown in Figures 1(A) to 1(C) and eight tendons in the case shown in Figure 1(D). In the following explanation of this embodiment, it is assumed that there are four PC tendons, and that PC tendons 200 are arranged as shown in Figure 1(A). Here, the drawings shown in these Figs. 1(A) to 1(D) are merely examples, and the present invention is not limited to these Figs. 1(A) to 1(D).

[0033] The tension fixing chair 1400 will be described in detail with reference to Fig. 2. The tension fixing chair 1400 is also called a reaction base, a reaction chair, or a chair, and in this embodiment, it has a chair-like shape with a flat plate-like planar portion 1420 having a substantially square plane and legs 1410 (the axial length of the PC steel material 200 of the legs 1410 is L(1)) at the four corners of the planar portion 1420. More specifically, the center of the planar portion 1420 has an abutment recess 1440 that abuts against the nose 1630 of the jack 1600 and a through hole 1430 through which the press-fit lock-off piston 1620 passes.

[0034] Because of this structure, when the tension fixing device 1000 is installed to perform the tension fixing method, the end face of the leg 1410 of the tension fixing chair 1400 (the face not connected to the flat portion 1420) abuts against the end face of the open end of the fixing plate 1300, and the nose 1630 of the jack 1600 abuts against the abutment recess 1440 of the flat portion 1420. To achieve this, a counter-load mount 1610 is provided between the anchor plate 1300 and the jack 1600 to act as a reaction mount when the tensioning piston 1610 of the jack 1600 is actuated.

[0035] Next, the press-fit plate 1500 will be described in detail with reference to Fig. 3. The press-fit plate 1500 generally includes a flat plate-like planar portion 1510 having a substantially square surface, two reinforcing ribs 1520 provided on the planar portion 1510, and rectangular holes 1514 through which the four legs 1410 of the tension fixing chair 1400 are inserted. However, this square hole 1514 is necessary when the press-in plate 1500 has a flat, planar portion 1510 so that the press-in plate 1500 can move in the direction of the fixing fixture 1200 when it receives force from the press-in lock-off piston 1620. However, if the press-in plate 1500 itself has a shape that does not interfere with the tensioning fixation chair 1400 (for example, a shape in which the planar portion 1510 does not have a flat portion in the center and is composed only of upper and lower portions where the hole portion 1530 and the small hole portion 1540 are provided, and the rib 1520 connects the upper and lower portions), such a square hole 1514 is not necessarily required. The press-in plate 1500 is not limited to a press-in plate 1500 (one having such a square hole 1514) as long as it is capable of moving in the direction of the fixing fixture 1200 when it receives force from the press-in lock-off piston 1620 without interfering with the tensioning fixation chair 1400.

[0036] The thickness of this press-in plate 1500 is not particularly limited as long as it has a strength sufficient to press-in the wedges 1210 of the four fixing fasteners 1200 into the sleeves 1220 to an approximately equal degree of press-in amount when pressed by the press-in lock-off piston 1620; however, in this embodiment, the strength of the press-in plate 1500 is weak due to the presence of the square holes 1514, and an appropriate thickness is set in addition to reinforcing the plate with the ribs 1520.

[0037] More specifically, at each of the four corners of the flat portion 1510, there is provided a hole 1530 through which the PC steel material 200 is inserted, and a pair of small holes 1540 for connecting bolts 1550, one above the other, which are screwed into female threads provided in the sleeve 1220 of the fixing fixture 1200, are provided on the central side (the press-fit lock-off piston 1620 side) of the hole 1530. Here, the diameter of the head of the connecting bolt 1550>the diameter of the small hole 1540>the diameter of the threaded portion of the connecting bolt 1550, and the head of the connecting bolt 1550 cannot pass through the hole 1530, but the threaded portion of the connecting bolt 1550 can pass through the hole 1530 (inserted state). The press-fit lock-off piston of the jack 1600 comes into contact with the center of the flat portion 1510 to press the press-fit plate 1500. This is shown by region 1512 of flat surface portion 1510 with which press-fit lock-off piston 1620 comes into contact.

[0038] Here, the jack used for tensioning and fixing the prestressing tendons is a normal center hole jack equipped with a lock-up piston for pressing. In this embodiment, the jack 1600 is a center hole type, and is equipped with a lock-off piston for pressing 1620 in addition to the tensioning piston 1610. Since the jack is a center hole type, the lock-off piston for pressing 1620 has a hollow cylindrical shape. In a normal tensioning and fixing method, the prestressing tendons are inserted into the hollow cylinder of the lock-off piston for pressing 1620 in order to tension and fix one prestressing tendon with one jack. However, in the tensioning and fixing device 1000 according to this embodiment, although the center hole type jack 1600 with the same lock-off piston is used, the prestressing tendons 200 are not inserted into the center hole of the jack or the hollow cylinder of the lock-off piston for pressing 1620.

[0039] In order to provide such a structure, the tensioning device 1000 is installed on the PC steel member 200 to perform the tensioning method, and when the press-fit lock-off piston 1620 of the jack 1600 is operated, the press-fit plate 1500 receives a force from the press-fit lock-off piston 1620 at the area 1512 of the flat portion 1510, and the press-fit plate 1500 moves in a direction to press the end face on the open end side of the wedge 1210 of the fixing fixture 1200 toward the sleeve 1220. Here, since the diameter of the head of the connecting bolt 1550>the diameter of the small hole portion 1540>the diameter of the threaded portion of the connecting bolt 1550, when the press-fit plate 1500 moves toward the fixing fixture 1200, the connecting bolt 1550 cannot pass through the hole portion 1530, but the threaded portion of the connecting bolt 1550 can pass through the hole portion (inserted state). The flat surface 1510 of the press-fit plate 1500 is provided with a square hole 1514 through which the leg 1410 of the tension fixing chair 1400 is inserted.

[0040] As a result, the PC steel 200 inserted in the hole 1530, the leg 1410 of the tension fixing chair 1400 inserted in the square hole 1514, and the connecting bolt 1550 inserted in the small hole 1540 can move toward the fixing fixture 1200 without interfering with the axial movement of the PC steel 200 of the press-in plate 1500 receiving force from the press-in lock-off piston 1620, and the press-in plate 1500 can press the end face on the open end side of the wedge 1210 toward the sleeve 1220. The area where the press-in plate 1500 presses the end face on the open end side of the wedge 1210 toward the sleeve 1220 is shown in Figure 3 as area 1532, and the state where the press-in plate 1500 presses the end face on the open end side of the wedge 1210 toward the sleeve 1220 is shown by a black arrow in Figure 5(B).

[0041] In this manner, the end faces on the open ends of the multiple (four in this case) wedges 1210 of the multiple (four in this case) fixing fasteners 1200 are pressed to press them into the sleeve 1220. At this time, the press-fitting plate 1500 acts in common on the multiple wedges 1210, so that the above-mentioned [Problem 1] to [Problem 4] can be solved. Here, the press-fit plate 1500 functions as a fall prevention mechanism. As described above, the press-fit plate 1500 is connected to the sleeve 1220 of the fixing fixture 1200 by the connecting bolt 1550. Since the diameter of the head of the connecting bolt 1550>the diameter of the small hole portion 1540 of the press-fit plate 1500>the diameter of the threaded portion of the connecting bolt 1550, the press-fit plate 1500 is connected to the sleeve 1220 of the fixing fixture 1200 so as to be movable in the longitudinal direction of the PC steel member 200.

[0042] When the tensioning device 1000 is set on the PC steel 200, including when tensioning is performed by operating the tensioning piston 1610 of the jack 1600, the flat surface 1510 of the press-in plate 1500 comes into contact with the end face on the open end side of the wedge 1210 (which is about to fall out of the sleeve 1220), thereby preventing the wedge 1210 from falling out of the sleeve 1220. More specifically, as shown in Fig. 5(B), the axial length relationship of the PC steel 200 is such that the gap length X between the open end face of the wedge 1210 of the fixing fixture 1200 and the press-in plate 1500 is shorter than the length Y of the wedge 1210 of the fixing fixture 1200, thereby preventing the wedge 1210 from falling out of the sleeve 1220. This relationship of Y>X is set to hold regardless of the axial position of the press-fit plate 1500, which is movable in the axial direction of the PC steel member 200. This makes it possible to solve the above-mentioned [Problem 5].

[0043] As described above, the jack 1600 constituting the tensioning and anchoring device 1000 according to this embodiment is a center hole type jack with a lock-off piston, and the other members themselves are basically known members, so detailed description will not be repeated here. However, even if the members are known, their arrangements, etc. may not be known, so they will be described below.

[0044] Next, the structure of the tensioning anchoring device 1000 will be described with reference to Fig. 4, which shows a side view of the tensioning anchoring device 1000 according to this embodiment before it is installed (set), and Figs. 5 and 6, which show the tensioning anchoring device 1000 after it is installed (set). Here, Fig. 5(A) is a side view of the tensioning anchoring device 1000 placed on the PC steel material 200, Fig. 5(B) is an enlarged view of region 5B in Fig. 5(A), Fig. 6(A) is a view seen from the arrow 6A in Fig. 5, and Fig. 6(B) is a view seen from the arrow 6B in Fig. 5.

[0045] First, as shown in Figure 4, one fixing plate 1300 and four fixing fasteners 1200 are provided at each end of the structure 100, and on both the fixed side and the tensioning side, the fixing fasteners 1200 are fixed to the fixing plate 1300 by fixing bolts 1250 that are inserted into two upper and lower holes (the two upper and lower holes that are on the outer side when viewed from the axis of the PC steel 200 and are farther from the axis in a plane perpendicular to the axis of the PC steel 200) that penetrate the axial direction of the PC steel 200 provided in the sleeve 1220 of the fixing fastener 1200 in a portion other than the inner cylindrical portion with a tapered surface, and that screw into female threaded holes provided in the fixing plate 1300.

[0046] In this embodiment, one-way pulling is adopted instead of the so-called two-way pulling, so as shown in Figure 4, the tensioning and fixing device 1000 of this embodiment is not installed (set) on the fixed side but only on the tensioning side. In the state shown in FIG. 4, the tensioning anchoring device 1000 according to this embodiment is installed on the tensioning side PC steel material 200, resulting in the state shown in FIGS.

[0047] As shown in Figures 5 and 6, a plurality (four in this case) of PC steel members 200 are arranged on the reaction plate 1310 as shown in Figure 1(A), and a plurality (four in this case) of tensioning fasteners 1100 that use the reaction plate 1310 to tension the PC steel members 200 are inserted into two upper and lower holes (the two upper and lower holes that are on the outer side when viewed from the axis of the PC steel member 200 and are farther from the axis in a plane perpendicular to the axis of the PC steel member 200) that penetrate the axial direction of the PC steel member 200 and are provided in a portion of the sleeve 1120 of the tensioning fastener 1100 other than the inner tube portion with a tapered surface, and the tensioning fasteners 1100 are fixed to the reaction plate 1310 by a fixing bolt 1150 that screws into a female threaded hole provided in the reaction plate 1310. As explained using Figure 4, a plurality of (here, four) fixing fasteners 1200 that fix the PC steel 200 using a fixing plate 1300 are arranged in the same arrangement as the plurality (here, four) tensioning fasteners 1100 (changing the axial position of the PC steel), and the fixing fasteners 1200 are inserted into two upper and lower holes (the two upper and lower holes that are on the outer side when viewed from the axis of the PC steel 200 and are farther from the axis in a plane perpendicular to the axis of the PC steel 200) that penetrate the axial direction of the PC steel 200 and are provided in a portion of the sleeve 1220 of the fixing fastener 1200 other than the inner tube portion with a tapered surface, and the fixing fasteners 1200 are fixed to the fixing plate 1300 by a fixing bolt 1250 that screws into a female threaded hole provided in the fixing plate 1300.

[0048] Then, when the tensioning piston 1610 of the jack 1600 is operated to tension a plurality (four in this case) of prestressing steel strands 200 (during tensioning), one reaction plate 1310 acts on the plurality (four in this case) of tensioning fasteners 1100, tensioning the plurality (four in this case) of prestressing steel strands 200 so that the tensioning forces are approximately equal (so that the tensioning forces are within a specified range and there is no difference that would cause problems in the compressive force applied to the structure 100). In this case, the plurality (four in this case) of prestressing steel strands 200 are stretched and tensioned from the plurality (four in this case) of tensioning fasteners 1100 via the single reaction plate 1310, so that the tension difference between the plurality (four in this case) of prestressing steel strands 200 can be reduced and tensioned.

[0049] During this tensioning, the press-in plate 1500 is connected to the sleeve 1220 of the fixing fixture 1200 so as to be freely movable in the longitudinal direction of the PC steel 200. During this tensioning, the PC steel 200 is stretched, and the press-in plate 1500 abuts against the end face on the open end side of the wedge 1210 which tends to fall out of the sleeve 1220 of the fixing fixture 1200, thereby preventing the wedge 1210 from falling out of the sleeve 1220.

[0050] During press-fitting after tensioning, the press-fit lock-off piston 1620 of the jack 1600 operates, and the press-fit lock-off piston 1620 presses the press-fit plate 1500, and the pressed press-fit plate 1500 presses the open-side ends of the wedges 1210 of the multiple (four here) fixing fixtures 1200 (in the direction of the black arrow in FIG. 5(B) at the area 1532 in FIG. 3(A)) to press-fit into the sleeve 1220 of the fixing fixture 1200. In this case, in order to press-fit the wedges 1210 of the multiple (four here) fixing fixtures 1200 into the sleeve 1220 via one press-fit plate 1500, the press-fitting amount difference of the multiple (four here) wedges 1210 can be reduced.

[0051] <How to establish tension> A method for tensioning and fastening a plurality of prestressing tendons using the tensioning and fastening device 1000 having the above-mentioned characteristic structure will be described in detail below with reference to Figs. 5 to 9. This tensioning and fastening method uses the above-mentioned tensioning and fastening device 1000 to tension and fasten a plurality of prestressing tendons that apply a compressive force to a structure. This is a method for tensioning and fixing multiple prestressing steel strands using a tensioning fixture and a fixing fixture consisting of an edge and a sleeve. In particular, this is a tensioning and fixing method that can minimize the tension difference (including the press-in difference due to the lock-off piston in this case) between multiple prestressing steel strands 200.

[0052] Fixing plate installation steps An anchor plate 1300 is installed on the end face of the open end of the PC steel member 200 on the tension side of the structure 100. In this embodiment, the structure 100 and the anchor plate 1300 shown in Fig. 1(A) are adopted. -Fixing fixture installation steps A plurality of (four in this example) fixing fixtures 1200 for fixing (fixing under tension) each PC steel 200 are installed on the fixing plate 1300 so that the sleeves 1220 abut against the end face on the open end side of the fixing plate 1300. In the fixing fixtures 1200, the wedges 1210 are always used in combination with the sleeves 1220, so in this step the wedges 1210 that bite into the PC steel 200 are inserted into the sleeves 1220 fixed to the fixing plate 1300.

[0053] More specifically, the sleeve 1220 of the fixing fixture 1200 is fixed to the fixing plate 1300 by a fixing bolt 1250 which is inserted into two upper and lower holes (the two upper and lower holes which are on the outer side as viewed from the axis of the PC steel 200 and are farther from the axis in a plane perpendicular to the axis of the PC steel 200) which penetrate the axial direction of the PC steel 200 and are provided in a portion of the sleeve 1220 of the fixing fixture 1200 other than the inner cylindrical portion with the tapered surface and which screw into a female threaded hole provided in the fixing plate 1300. The wedge 1210 is set in the sleeve 1220 fixed to the fixing plate 1300 so that the tapered surface on the inner circumference of the fixed sleeve 1220 abuts on the tapered surface on the outer circumference of the wedge 1210 which bites into the PC steel 200 on its inner circumference.

[0054] Jack installation steps A jack 1600 equipped with a tensioning piston 1610 and a press-in lock-off piston 1620 is installed on the open end side of the prestressing steel strand 200. At this time, a center-hole type jack, which is most commonly used for tensioning and fixing prestressing steel strands, is adopted and installed in the same manner as that jack (except that one jack is used to handle multiple (here, four) prestressing steel strands 200). The positional relationship between this jack 1600 and the tensioning and fixing chair 1400, press-in plate 1500, etc. will be described immediately before the tensioning step. Press-in plate installation steps A press-in plate 1500 is installed which acts commonly on multiple wedges 1210 and presses the end faces on the open ends of the multiple wedges 1210 in response to force from a press-in lock-off piston 1620 which operates in a direction to press the end faces on the open ends of the wedges 1210 of the fixing fixture 1200.

[0055] More specifically, the press-in plate 1500 is screwed into two upper and lower female threaded holes (the two upper and lower holes are on the inside when viewed from the axis of the PC steel material 200 and closer to the axis in a plane perpendicular to the axis of the PC steel material 200) that do not penetrate partway in the axial direction of the PC steel material 200 (although it is acceptable for them to penetrate) provided in the sleeve 1220 of the fixing fixture 1200 other than the inner tube portion with a tapered surface, and the press-in plate 1500 is freely installed in the axial direction of the PC steel material 200 to the fixing fixture 1200 by a connecting bolt 1550 inserted into a small hole portion 1540 provided in the press-in plate 1500. -Steps for setting up the tension-fixing chair A tension fixing chair 1400 having a through hole 1430 through which the press-fit lock-off piston 1620 passes is placed so as to abut against the end face of the open end side of the fixing plate 1300 and the nose 1630 of the jack 1600 .

[0056] Reaction plate installation steps The open end of the jack 1600 receives a force from a tensioning piston 1610 that operates in a direction to stretch the PC steel 200, and also acts on multiple tensioning fixtures 1100 in common. 16. Install the reaction plate 1310 (integral with the jack 1600) to support the load. -Tensioning fixture installation steps A plurality of (four in this case) tensioning fasteners 1100 for fixing (tensioning and fastening) each PC steel 200 are installed on the open end side of the reaction plate 1310. As with the fixing fasteners 1200, the wedges 1110 in the tensioning fasteners 1100 are always used in combination with the sleeves 1120, so in this step the wedges 1110 that bite into the PC steel 200 are inserted into the sleeves 1120 fixed to the reaction plate 1310.

[0057] More specifically, the sleeve 1120 of the tensioning fixture 1100 is fixed to the reaction plate 1310 by a fixing bolt 1150 which is inserted into two upper and lower holes (the two upper and lower holes which are on the outer side as viewed from the axis of the PC steel 200 and are farther from the axis in a plane perpendicular to the axis of the PC steel 200) which penetrate the axial direction of the PC steel 200 and are provided in a portion of the sleeve 1120 of the tensioning fixture 1100 other than the inner cylindrical portion with the tapered surface and which screw into a female threaded hole provided in the reaction plate 1310. The wedge 1110 is set in the sleeve 1120 fixed to the reaction plate 1310 so that the tapered surface on the inner circumference of the fixed sleeve 1120 abuts on the tapered surface on the outer circumference of the wedge 1110 which bites into the PC steel 200 on its inner circumference.

[0058] Through the steps up to this point, the tensioning anchoring device 1000 according to this embodiment is installed on a plurality (four in this case) of PC steel members 200 in the state shown in Figures 5 and 6. At this time, the anchoring plate 1300 is provided in contact with the structure 100, and the sleeves 1220 of the fixing fixture 1200 are fixed to the anchoring plate 1300 by fixing bolts 1250 (two per sleeve 1220), and the wedge 1210 is set in the sleeve 1220. The open end face of the leg 1410 of the tensioning anchoring chair 1400 is in contact with the anchoring plate 1300, and the nose 1630 of the jack 1600 is in contact with the contact recess 1440 provided in the flat portion 1420 of the tensioning anchoring chair 1400. 3. The press-fit lock-off piston 1620 of the jack 1600 can penetrate the through-hole 1430 provided in the flat surface 1420 of the tension fixing chair 1400 and press the area 1512 of the press-fit plate 1500 shown in FIG.

[0059] Since the connecting bolt 1550 connecting the fixing fixture 1200 and the press-in plate 1500 has a diameter such that the diameter of the head of the connecting bolt 1550 is greater than the diameter of the small hole portion 1540 and greater than the diameter of the threaded portion of the connecting bolt 1550, the press-in plate 1500 can move freely in the axial direction of the PC steel 200, and the press-in lock-off piston 1620 can press the area 1512 of Figure 3, and the press-in plate 1500 pressed by the press-in lock-off piston 1620 can press the open side ends of the wedges 1210 of multiple (here, four) fixing fixtures 1200 (in the direction of the black arrow in Figure 5(B) at the area 1532 of Figure 3(A)) to press them into the sleeves 1220 of the fixing fixture 1200.

[0060] In addition, multiple (here, four) tensioning fasteners 1100 are installed on the reaction plate 1310 (the sleeve 1120 of the tensioning fastener 1100 is fixed by screwing it into the female thread of the reaction plate 1310 with a fixing bolt 1150), and the multiple (here, four) tensioning fasteners 1100 can be tensioned and fixed simultaneously through one reaction plate by the tensioning piston 1610.

[0061] Furthermore, when the tensioning fixing device 1000 of this embodiment is installed on multiple (here, four) PC steel members 200 in this manner, the press-in plate 1500, which is installed so as to be sandwiched between the tensioning fixing chair 1400 and the fixing fixture 1200, can prevent the wedge 1210 from falling out of the sleeve 1220, because the axial length relationship of the PC steel members 200 is such that the gap length X between the open side end face of the wedge 1210 of the fixing fixture 1200 and the press-in plate 1500 is shorter than the length Y of the wedge 1210 of the fixing fixture 1200, as shown in Figure 5 (B). The tensioning and anchoring device 1000 according to this embodiment installed as shown in Figs. 5 and 6 further executes the following steps.

[0062] ·Tension Step After each of the above-mentioned steps, the tensioning piston 1610 of the jack 1600 is operated, and a predetermined load is applied using the reaction plate 1310 and the tensioning fixture 1100 to tension multiple (here, four) PC steel members 200. At this time, the nose 1630 of the jack 1600 abuts against the abutment recess 1440 of the tensioning and fixing chair 1400, and the open end face of the leg 1410 of the tensioning and fixing chair 1400 abuts against the fixing plate 1300, so that the tensioning piston 1610 presses against the fixing plate 1300 via the nose 1630 of the jack 1600, and the tensioning piston 1610 moves in the direction of the outlined arrow in Fig. 7. At this time, the wedge 1110 of the tensioning fixing tool 1100 fixed to the reaction plate 1310 moves together with the jack 1600 while biting (gripping) the PC steel 200, so that the PC steel 200 is pulled out from inside the concrete and extended. Since the nose 1630 of the jack 1600 receives a reaction force from the structure 100 via the tensioning anchoring chair 1400, the tensile force (tension) of the PC steel 200 generated by the stretching of the PC steel 200 is transmitted to the structure 100 via the anchoring plate 1300, and prestress is introduced into the structure 100.

[0063] Press-in step With a predetermined load applied, the press-in lock-off piston 1620 is actuated, and the press-in plate 1500 is used to press the open end faces of the wedges 1210 of the multiple fixing fixtures 1200, thereby pressing the wedges 1210 into the sleeves 1220 of the fixing fixtures 1200. At this time, the press-fit lock-off piston 1620 presses the portion of the press-fit plate 1500 in the region 1512 in Fig. 3 as shown by the outlined arrow in Fig. 8, and the pressed press-fit plate 1500 presses the open end of the wedge 1210 of the fixing fixture 1200 in the region 1532 in Fig. 3 as shown by the filled arrow in Fig. 8, and presses in the wedge 1210 that protrudes from the sleeve 1220 in the tensioning step. At this time, as shown in Fig. 5(B), the axial length relationship of the PC steel 200 is such that the gap length X between the open end face of the wedge 1210 of the fixing fixture 1200 and the press-fit plate 1500 is shorter than the length Y of the wedge 1210 of the fixing fixture 1200, so that the wedge 1210 does not fall out of the sleeve 1220 and can be pressed in normally.

[0064] Here, the fixing plate 1300, the fixing fixture 1200, the tensioning fixing chair 1400, the press-in plate 1500 and the press-in lock-off piston 1620 of the jack 1600 are shown in a state before press-in in FIG. 9(A), which is an enlarged view of FIG. 7, and in a state during press-in in FIG. 9(B), which is an enlarged view of FIG. 8. As shown in Figures 9(A) and 9(B), during press-fitting, a pressing force of press-fitting lock-off piston 1620 is generated that was not generated before press-fitting. Press-fitting lock-off piston 1620 presses the portion of press-fitting plate 1500 in region 1512 in Figure 3 as shown by the outlined arrow in Figure 9(B), and the pressed press-fitting plate 1500 presses the open end of wedge 1210 of fixing fixture 1200 in region 1532 in Figure 3 as shown by the filled arrow in Figure 8, thereby pressing in wedge 1210 that protruded from sleeve 1220 in the tensioning step.

[0065] In this case, in order to press the wedge 1210 of the fixing fixture 1200 into the sleeve 1220 by the press-fit lock-off piston 1620 in this manner (because it is necessary to secure a pressing allowance for the press-fit plate 1500 by the press-fit lock-off piston 1620), it is necessary to configure the length of the PC steel 200 in the tensioning chair 1400 in the longitudinal direction to be at least longer than the sum of the length of the fixing fixture 1200 in the longitudinal direction and the length of the press-fit plate 1500. More specifically, for the longitudinal length of the PC steel 200 shown in FIG. 9, the length L(1) of the leg 1410 in the tensioning chair 1400 is set to be at least equal to the sum of the length of the fixing fixture 1200 (including the length of the expanded side of the wedge 1210 before tensioning) and the length of the press-fit plate 1500 (including the length of the flat portion 15 pressed by the press-fit lock-off piston). The thickness of the conductor must be at least as long as the sum of the thickness of the conductor and the thickness of the conductor.

[0066] Post-processing steps After the wedge 1210 is pressed into the sleeve 1220 of the fixing fixture 1200 in the pressing step, the specified load of the jack 1600 is released, and everything other than the fixing plate 1300 and the fixing fixture 1200 is removed, and the PC steel material 200 is cut leaving the required excess length. As described above, according to the device for tensioning and fastening multiple PC steel members and the method for tensioning and fastening multiple PC steel members of this embodiment, when multiple PC steel members that apply compressive force to a structure are tensioned and fastened using tensioning fasteners and fixing fasteners composed of wedges and sleeves, the tension difference between the multiple PC steel members can be reduced and the compressive force can be applied to the structure as evenly as possible.

[0067] In addition, according to the device for tensioning and fixing multiple PC steel members and the method for tensioning and fixing multiple PC steel members of this embodiment, when multiple PC steel members that apply compressive force to a structure are tensioned and fixed using a tensioning fixture and a fixing fixture consisting of a wedge and a sleeve, the possibility of the wedge falling off from the wedge receiving member (hole) can be reduced, including when the PC steel members are tensioned before the wedge pressing-in operation.

[0068] Second embodiment Next, a characteristic structure of the tension fixing device 2000 for multiple PC tendons according to the second embodiment of the present invention will be described in detail with reference to Figs. 10 to 16, and then a method for tension fixing multiple PC tendons using the tension fixing device 2000 having this technical structure will be described in detail. As described above, the same structures in the first and second embodiments are given the same reference numerals, and the explanations of those structures in the second embodiment will not be repeated in the second embodiment because they overlap with the explanations in the first embodiment. Furthermore, the explanations common to the tension fixing method using the tension fixing device 1000 according to the first embodiment and the tension fixing method using the tension fixing device 2000 according to the second embodiment will not be repeated in the second embodiment because they overlap with the explanations in the first embodiment.

[0069] The tensioning and fixing device 2000 according to the second embodiment and the tensioning and fixing device 1000 according to the first embodiment differ in the details of the structure of the press-in plate, and further includes a wedge pressing member 2800 shown in Fig. 11 which is not included in the tensioning and fixing device 1000. Regarding the press-in plate, instead of the press-in plate 1500 shown in Fig. 3 which was used in the first embodiment, the second embodiment uses a press-in plate 2500 shown in Fig. 10.

[0070] Here, the wedge pressing member 2800, which is a member separate from the press-fit plate 1500, functions as a fall prevention mechanism. The tension fixing device 2000 further includes a substantially flat wedge pressing member 2800 between the press-fit plate 2500 and the fixing fixture 1200, which is connected to the fixing fixture 1200 so as to be movable in the longitudinal direction of the PC steel 200, and which has a hole 2830 through which the PC steel 200 is inserted and a small hole 2840 through which a connecting member (here, a connecting bolt 2550) connected to the fixing fixture 1200 is inserted. The fall prevention mechanism prevents the wedge pressing member 2800, which is separate from the press-fit plate 2500, from falling off the sleeve 1220 during tensioning by abutting against the end face on the open end side of the wedge 1210.

[0071] In the following, with reference to Figs. 10 to 16, the structure of the tensioning and fixing device 2000 according to this embodiment will be described in detail, focusing only on the differences from the tensioning and fixing device 1000 according to the first embodiment. First, the press-fit plate 2500 will be described with reference to Fig. 10 corresponding to Fig. 3. The difference is that a pair of small holes 2540 for connecting bolts 2550, one above the other, are provided on the central side (the press-fit lock-off piston 1620 side) of the hole 1530 through which the PC steel material 200 is inserted, to screw into female threads provided in the sleeve 1220 of the fixing fixture 1200. Here, the diameter of the small hole 2540 is greater than the diameter of the head of the connecting bolt 2550 (>the diameter of the threaded portion of the connecting bolt 2550), and both the head and the threaded portion of the connecting bolt 2550 can pass through the small hole 2540 (inserted state). Also, in this tension fixing device 2000, the press-fit plate 15 10 does not show an area corresponding to area 1532 in FIG. 3, since a separate wedge pressing member 2800, rather than 00, presses the wedge 1210 of the fixing fixture 1200 into the sleeve 1220 (although it also prevents the wedge 1210 from falling out of the sleeve 1220).

[0072] 11, a wedge pressing member 2800 that is not provided in the tensioning and fixing device 1000 but is provided in the tensioning and fixing device 2000 according to the present embodiment will be described. The wedge pressing member 2800 prevents the wedge 1210 from falling off the sleeve 1220, and also presses the wedge 1210 of the fixing fixture 1200 into the sleeve 1220.

[0073] 11, the wedge pressing member 2800 has a generally flat plate shape with six holes, the width (horizontal length on the paper) of which is about the same as that of the fixing fixture 1200, and the height (vertical length on the paper) of which is about 1.2 times that of the fixing fixture 1200. The thickness of the wedge pressing member 2800 is not particularly limited as long as it has a strength sufficient to press the wedge 1210 of the fixing fixture 1200 into the sleeve 1220.

[0074] Each of both ends of the flat portion 2810 of the wedge presser member 2800 is provided with a hole 2830 through which the PC steel material 200 is inserted, and a pair of small holes 2840 for connecting bolts 2550, one above the other and one below the other, which are screwed into female threads provided in the sleeve 1220 of the fixing fastener 1200, are provided toward the center (the press-fit lock-off piston 1620 side) from the hole 2830. Here, the diameter of the head of the connecting bolt 2550>the diameter of the small hole 2840>the diameter of the threaded portion of the connecting bolt 2550, and the head of the connecting bolt 2550 cannot pass through the small hole 2840 but the threaded portion of the connecting bolt 2550 can pass through the small hole 2840 (inserted state).

[0075] 3A, which presses the open end of the wedge 1210 of the fixing fixture 1200 in the press-fitting step, corresponds to the area 2832 shown in Fig. 11. However, the member that presses the open end of the wedge 1210 of the fixing fixture 1200 is the press-fitting plate 1500 in the tension fixing device 1000, but is the wedge pressing member 2800 in the tension fixing device 2000.

[0076] 12 and 13, the wedge presser members 2800 are provided at the upper and lower ends of the fixing fixture 1200 and the press-fit plate 1500, respectively (one at each of the upper and lower locations so that the direction from the back to the front on the paper is the longitudinal direction of the wedge presser member 2800). The following is satisfied: diameter of the threaded portion of the connecting bolt 2550 < diameter of the small hole portion 2840 of the wedge presser member 2800 < diameter of the head portion of the connecting bolt 2550 < diameter of the small hole portion 2540 of the press-fit plate 2500. For this reason, the head portion of the connecting bolt 2550 which secures the press-fit plate 2500 to the fixing fixture 1200 (which screws into the female threaded hole of the sleeve of the fixing fixture 1200) is

[0077] The bolt 2550 can move to the right side of the paper surface of the press-fit plate 2500 by passing through the small hole 2540 (the diameter of which is greater than the diameter of the head of the bolt 2550) of the press-fit plate 2500. The connecting bolt 2550 cannot pass through the small hole 2840 (having a diameter < the diameter of the head of the connecting bolt 2550) of the wedge holding member 2800, and cannot move to the right side of the page of the wedge holding member 2800 (if this were to happen, there is a possibility that the wedge holding member 2800 would fall).

[0078] When the tensioning and fixing device 2000 is set on the PC steel 200, including when the tensioning piston 1610 of the jack 1600 is operated to tension the PC steel 200, the flat surface 2810 of the wedge pressing member 2800 comes into contact with the end face on the open end side of the wedge 1210 (which is about to fall out of the sleeve 1220), thereby preventing the wedge 1210 from falling out of the sleeve 1220. More specifically, as shown in Fig. 12(B), the axial length relationship of the PC steel 200 is such that the gap length Z between the open end face of the wedge 1210 of the fixing fixture 1200 and the wedge pressing member 2800 is shorter than the length Y of the wedge 1210 of the fixing fixture 1200, thereby preventing the wedge 1210 from falling out of the sleeve 1220.

[0079] The tension fixing device 2000 having the above-mentioned characteristic structure is used to fix tension on multiple PC steel members. Regarding the fastening method, only the points that differ from the tensioning and fastening device 1000 according to the first embodiment will be described in detail with reference to Figs. The wedge pressing member 2800, which is not provided in the tensioning and fixing device 1000 according to the first embodiment, may be installed together with the press-fitting plate 2500, which replaces the press-fitting plate 1500, in the above-mentioned press-fitting step.

[0080] In addition, with regard to Figure 14 which explains the tensioning step and Figure 16(A) which shows the state before pressing, press-fit plate 2500 is shown instead of press-fit plate 1500, connecting bolt 2550 is shown instead of connecting bolt 1550, and wedge holder 2800 is newly shown, except that the tensioning step is the same as in Figure 7, and the state before pressing is the same as in Figure 9(A).

[0081] Press-in step Only the differences from the first embodiment will be described below. With a predetermined load applied, the press-in lock-off piston 1620 is actuated to use the press-in plate 1500 and the wedge pressing member 2800 to press the end faces on the open end side of the wedges 1210 of the multiple fixing fixtures 1200, thereby pressing the wedges 1210 into the sleeves 1220 of the fixing fixtures 1200.

[0082] At this time, the press-in lock-off piston 1620 presses the press-in plate 2500 in area 1512 in FIG. 10, as shown by the white arrow in FIG. 15, and the pressed press-in plate 2500 presses the wedge holding member 2800 as shown by the gray arrow in FIG. 15, and the pressed wedge holding member 2800 presses the open end of the wedge 1210 of the fixing fixture 1200 in area 2832 in FIG. 11, as shown by the black arrow in FIG. 15 (more specifically, FIG. 12(C)), to press in the wedge 1210 that protrudes from the sleeve 1220 in the tensioning step. 12(B), the axial length relationship of the PC steel 200 is such that the gap length Z between the open end face of the wedge 1210 of the fixing fixture 1200 and the wedge presser member 2800 is shorter than the length Y of the wedge 1210 of the fixing fixture 1200, preventing the wedge 1210 from falling out of the sleeve 1220. This Y>Z relationship is set so as to hold regardless of the axial position of the PC steel 200 of the press-in plate 2500, which is movable in the axial direction of the PC steel 200, and regardless of the axial position of the wedge presser member 2800, which is movable in the axial direction of the PC steel 200, as a result of the head of the connecting bolt 2550 passing through (being inserted into) the small hole 2540 of the press-in plate 2500.

[0083] In this way, the wedge holding member 2800 prevents the wedge 1210 from falling out of the sleeve 1220 of the fixing fixture 1200, and the wedge holding member 2800 presses the open end of the wedge 1210 of the fixing fixture 1200, thereby pressing in the wedge 1210 that has protruded from the sleeve 1220 during the tensioning step. Here, the fixing plate 1300, the fixing fixture 1200, the tensioning fixing chair 1400, the wedge holding member 2800, the press-in plate 2500 and the press-in lock-off piston 1620 of the jack 1600 are shown in their states before press-in in FIG. 16(A), which is an enlarged view of FIG. 14, and in their states during press-in in FIG. 16(B), which is an enlarged view of FIG. 15.

[0084] As shown in Figures 16(A) and 16(B), during press-fitting, a pressing force of the press-fitting lock-off piston 1620 is generated that was not generated before the press-fitting. The press-fitting lock-off piston 1620 presses the portion of the press-fitting plate 2500 in the region 1512 in Figure 10 as shown by the outlined arrow in Figure 15, and the pressed press-fitting plate 2500 presses the wedge pressing member 2800 as shown by the gray arrow in Figure 15, and the pressed wedge pressing member 2800 presses the open end of the wedge 1210 of the fixing fixture 1200 in the region 2832 in Figure 11 as shown by the black arrow in Figure 15, thereby pressing in the wedge 1210 that protrudes from the sleeve 1220 in the tensioning step.

[0085] In this case, in order to press the wedge 1210 of the fixing fixture 1200 into the sleeve 1220 by the press-fit lock-off piston 1620 in this manner (press-fit lock-off Since it is necessary to secure a pressing margin for the press-in plate 1500 by the piston 1620), it is necessary to configure the longitudinal length of the PC steel 200 in the tensioning chair 1400 to be at least longer than the sum of the longitudinal length of the fixing fixture 1200 and the length of the press-in plate 1500. More specifically, regarding the longitudinal length of the PC steel 200, it is necessary to configure the length L(1) of the leg 1410 in the tensioning chair 1400 to be at least longer than the sum of the length of the fixing fixture 1200 (including the length of the expansion side of the wedge 1210 before tensioning) and the length of the press-in plate 2500 (the thickness of the flat portion 2510 pressed by the press-in lock-off piston).

[0086] As described above, the tensioning and fixing device for multiple PC steel members and the tensioning and fixing method for multiple PC steel members of this embodiment can also achieve the effect of solving [Problem 1] to [Problem 5] in the same way as the tensioning and fixing device for multiple PC steel members and the tensioning and fixing method for multiple PC steel members of the first embodiment. It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims.

[0087] For example, as an example of such a modification, in any of the above-mentioned embodiments, the fixing plate, fixing fixture, tensioning fixing chair, press-in plate, jack, reaction plate, and tensioning fixture are all described as separate components, and the fixing fixture is fixed to the fixing plate by bolts and the tensioning fixture is fixed to the reaction plate by bolts, but instead of these fixing methods, welding may be used, for example, and the press-in lock-off piston and press-in plate may be integrated by welding or the like. [Industrial Applicability]

[0088] The present invention relates to a technology for applying compressive force to structures by placing PC steel members in the structures and tensioning the PC steel members, and is particularly advantageous in that when multiple PC steel members are tensioned by one-sided or two-sided tension, the tension difference between the PC steel members can be reduced, thereby applying compressive force as evenly as possible to the structures. [Explanation of symbols]

[0089] 100, 102 structures 200 PC steel material 1000, 2000 tension fixing device 1100 Tension anchor 1200 Fixing fixture 1300 Fixing plate 1310 Reaction Plate 1400 Tension Fixation Chair 1500, 2500 press-fit plate 1600 Jack (hydraulic jack) 2800 Wedge holding member

Claims

1. A tensioning and fastening device for a plurality of PC steel members, which applies a compressive force to a structure, tensions and fastens the plurality of PC steel members by using tensioning fasteners and fixing fasteners each composed of a wedge and a sleeve, In the tensioning fixture and the fixing fixture, a plurality of wedges that bite into and hold each of the plurality of PC steel members at their inner peripheries are fixed by abutting tapered surfaces on the outer peripheries of the wedges against tapered surfaces on the inner peripheries of a plurality of sleeves through which each of the PC steel members passes, A jack provided on the open end side of the PC steel material and including a tensioning piston and a press-fit lock-off piston; A reaction plate that acts in common on a plurality of tension fixing devices and is provided on the open end side of the jack so as to receive a force from a tension piston that operates in a direction to stretch the PC steel material; A plurality of tension fixing devices are provided on the open end side of the reaction plate and fix each of the PC steel members; a fixing plate that abuts against an end surface of the structure on the open end side; a plurality of fixing fasteners, the number of which is the same as the PC steel members, each of which has a sleeve fixed to the fixing plate so as to abut against an end surface of the open end side of the fixing plate and fixes each of the PC steel members; a press-fitting plate that is provided to receive a force from a press-fitting lock-off piston that operates in a direction to press the end faces of the open ends of the wedges of the fixing fixture toward the sleeve, and that presses the end faces of the open ends of the wedges of the fixing fixture and acts commonly on the multiple wedges; a tensioning and fixing chair that abuts against the end face on the open end side of the fixing plate and the nose of the jack and has a through hole through which the press-in lock-off piston passes.

2. The tensioning anchoring device according to claim 1 , wherein the longitudinal length of the PC steel member in the tensioning anchoring chair is at least longer than the sum of the length of the fixing fastener and the length of the press-in plate in the longitudinal direction.

3. The tensioning anchoring device according to claim 1 or claim 2, further comprising a fall prevention mechanism that prevents the wedge of the fixing anchoring device from falling out of the sleeve of the fixing anchoring device during tensioning in which the PC steel material is stretched by the tensioning piston.

4. the press-in plate is connected to the fixing fixture so as to be movable in the longitudinal direction of the PC steel, and includes a substantially flat plate-shaped portion having a hole through which the PC steel is inserted and a hole through which a connecting member connected to the fixing fixture is inserted; The tensioning and fixing device according to claim 3 , wherein the fall prevention mechanism prevents the press-fit plate from falling off the sleeve by abutting against an end face of the wedge on the open end side during tensioning.

5. The tensioning anchoring device further includes a substantially flat wedge pressing member between the press-in plate and the fixing fixture, the wedge pressing member being connected to the fixing fixture so as to be movable in the longitudinal direction of the PC steel, the wedge pressing member having a hole through which the PC steel is inserted and a hole through which a connecting member connected to the fixing fixture is inserted, The tensioning and fixing device according to claim 3 , wherein the fall prevention mechanism prevents the wedge from falling out of the sleeve by abutting the wedge pressing member, which is separate from the press-in plate, against the end face of the open end of the wedge during tensioning.

6. A method for tensioning and fastening a plurality of PC steel members, which apply a compressive force to a structure, using a tensioning fastener and a fixing fastener each composed of a wedge and a sleeve, comprising: In the tensioning fixture and the fixing fixture, a plurality of wedges that bite into and hold each of the plurality of PC steel members at their inner peripheries are fixed by abutting tapered surfaces on the outer peripheries of the wedges against tapered surfaces on the inner peripheries of a plurality of sleeves through which each of the PC steel members passes, a step of providing an anchor plate in contact with an end surface of the PC steel member on an open end side of the structure; providing a plurality of fixing fasteners for fixing the PC steel members to the fixing plate so that a sleeve abuts against an end surface of the fixing plate on the open end side; Providing a jack having a tensioning piston and a press-fit lock-off piston on the open end side of the PC steel; a step of providing a press-fit plate acting commonly on the plurality of wedges, which presses the end faces of the open ends of the plurality of wedges in response to a force from a press-fit lock-off piston operating in a direction to press the end faces of the open ends of the wedges of the fixing fixture; providing a tension anchoring chair having a through hole through which the press-fit lock-off piston passes so as to abut against the open end surface of the anchoring plate and the nose of the jack; a step of providing a reaction plate on the open end side of the jack, the reaction plate receiving a force from a tensioning piston that operates in a direction to stretch the PC steel and acting commonly on a plurality of tensioning fasteners; Providing a plurality of tension fixing devices for fixing each of the PC steel members on the open end side of the reaction plate; After each of the steps, a step of operating a tensioning piston of the jack to tension the plurality of PC steel members by applying a predetermined load using the reaction plate and the tensioning fixture; a step of operating the press-fit lock-off piston while applying the predetermined load, and using the press-fit plate to press the end faces of the open ends of the wedges of the plurality of fixing fixtures, thereby press-fitting the wedges into the sleeves of the fixing fixtures; a wedge is pressed into the sleeve of the fixing fixture, and then the specified load is released, and all parts other than the fixing plate and the fixing fixture are removed, and the PC steel is cut leaving a necessary slack length.

Images