PC steel connector, PC steel anchoring method, PC steel connection method, and bridge widening method.

Abstract

By making the outer diameter as small as possible, PC steel materials can be connected accurately and reliably even in narrow construction areas. [Solution] The coupler sheath type PC steel connector 1000 includes a primary anchoring device including a sleeve 116 and a wedge 114 that tensionably hold the protruding primary PC steel 10, a secondary anchoring device that tensionably holds the secondary PC steel 20, a plug 600 which is a connecting member that connects the primary anchoring device and the secondary anchoring device, and a correction jig 170 that corrects the set amount generated when the primary PC steel 10 is pulled in due to the protrusion of the primary PC steel. The correction jig 170 includes a bearing plate 180 and a fixing member 190 whose outer diameter is less than or equal to the outer diameter of the sleeve 116 and plug 600, through which the primary PC steel 10 is inserted and which screws into the bearing plate 180, and corrects the set amount by changing the screw state between the bearing plate 180 and the fixing member 190.

Description

Technical Field

[0001] The present invention relates to a connector for PC steel materials that connects an existing PC steel material in which a tensile force has already been introduced in an existing concrete member and a newly installed PC steel material disposed in a newly installed concrete member so as to be continuous with the existing concrete member. Furthermore, the present invention relates to a fixing method for PC steel materials, a connecting method for PC steel materials, and a method for widening a bridge using such a connector for PC steel materials. In the present invention, PC steel materials (which may be referred to as PC steel bars) include PC steel wires, PC steel bars, and PC steel stranded wires (PC steel twisted wires), as well as PC steel materials whose outer surfaces are coated (coated) with a resin (such as epoxy), and also include their异形types.

Background Art

[0002] Structures in which PC steel materials, which are tension members, are disposed in concrete members and fixed to the concrete members in a state where a tensile force is introduced to introduce prestress are widely used. Most of these PC steel materials are inserted into a sheath embedded in the concrete member and integrated with the concrete member by the adhesive force of the grout that is grouted and cured after the tensile force is introduced.

[0003] In the case of structures in which prestress is introduced by such PC steel materials, such as repair, renovation, or widening of bridge girders (the present invention particularly relates to widening), it may be necessary. In such a case, it is desirable to place new concrete so as to be continuous with the existing concrete member and introduce prestress so as to be integrated. For this purpose, it is desirable to connect the PC steel materials disposed in the existing concrete member to the PC steel materials disposed in the newly installed concrete member and introduce a tensile force so as to be continuous from the existing concrete member to the newly installed concrete member.

[0004] However, PC steel bars placed within existing concrete members are often anchored to the concrete member at their ends by anchoring devices, and the PC steel bars are frequently cut short on the back side of the anchoring devices. Furthermore, measures to prevent corrosion are widely taken by embedding the anchoring devices and the ends of the PC steel bars within the concrete. Therefore, even if the anchored ends of the PC steel bars are chipped out from within the concrete member, it is difficult to connect new PC steel bars to these existing ones. Moreover, removing the anchoring devices is not possible when large tensile forces are applied.

[0005] More specifically, it is conceivable that after PC steel bars are placed and prestressing is introduced, the prestressed concrete, which has been integrated with grout, will be partially chipped away and demolished, and the new side will be reconstructed, such as by widening, and prestressing will be introduced again. In this case, the existing PC steel bars have anchoring devices (wedge type, screw type) placed at their ends and are under tension, and are integrated with the structure by grout. However, when partially demolished, the adhesion of the PC steel bars on the demolished side is impaired (part of the integration is damaged), and the PC steel bars will exhibit a behavior of slightly sinking into the structure. Therefore, it is desirable to re-tension and anchor the ends of the existing side. Furthermore, in most cases, connection between the existing PC steel bars and the new PC steel bars is necessary in order to integrate the new PC steel bars with the existing PC steel bars.

[0006] In view of these circumstances, Japanese Patent Publication No. 6083702 (Patent Document 1) discloses a method for connecting prestressed concrete (PC) steel members, which are placed within an existing concrete member and have tension already been introduced, and a method for widening a bridge using this PC steel member connection method.

[0007] The method for connecting PC steel members disclosed in Patent Document 1 is a method for connecting PC steel members such that tensile force is transmitted between an existing PC steel member, which is fixed to an existing concrete member with tension applied and has an adhesive force acting on its circumferential surface, and a new PC steel member, which is placed in a new concrete member and has tensile force applied to it, and a new PC steel member, which is placed in a new concrete member and has tensile force applied to it. The method involves removing an anchoring device provided at the end of the existing PC steel member that is connected to the new PC steel member, and chipping out the end embedded in the existing concrete member so that it protrudes from the existing concrete member; a female cone with a cylindrical outer circumference having a male thread formed thereon, through which the existing PC steel member is inserted; an anchoring nut screwed onto the male thread formed on the outer circumference of the female cone; and a male screw that is pressed between the inner circumferential surface of the hollow hole of the female cone and the outer circumferential surface of the existing PC steel member inserted into the hollow hole to fix the existing PC steel member and the female cone. The method is characterized by including the steps of: attaching an anchoring device, comprising a cone and a bearing plate that abuts against the anchoring nut and transmits the tensile force of the existing PC steel material to the existing concrete member, to a protruding portion of the existing PC steel material; filling the space between the bearing plate and the existing concrete member with concrete or mortar to enable the transmission of the tensile force of the existing PC steel material to the existing concrete member; screwing a tensioning member into a male thread formed on the outer circumference of the female cone and pulling the tensioning member in the axial direction of the existing PC steel material, and tightening the anchoring nut so that it is in close contact with the bearing plate while the tensioning member is pulled; and screwing a first female thread formed on one end of a coupler for connecting the existing PC steel material and the newly installed PC steel material into a male thread formed on the outer circumference of the female cone, and connecting it to one end of the newly installed PC steel material via a second female thread formed on the other end of the coupler.

[0008] In the PC steel connection method disclosed in Patent Document 1, the ends of the PC steel placed within an existing concrete member are exposed by chipping away at the concrete member, and the anchoring device is removed. Generally, if the PC steel is integrated with the concrete member by adhesive forces such as grout, even if the anchoring device is removed, tension is maintained in most of the longitudinal direction of the PC steel, and the prestress of the concrete member is also maintained. However, in this state, tensile force is transmitted to the concrete member by the adhesive force acting on the circumferential surface of the PC steel, and the adhesive force may be gradually lost due to vibrations of the concrete member, potentially reducing the prestress introduced into the concrete member. In contrast, in the PC steel connection method disclosed in Patent Document 1, by attaching an anchoring device to the PC steel exposed by chipping away at the existing concrete, the reduction in presslessness can be suppressed by fixing it to the existing concrete member while under tension. At this time, by using a male cone (wedge method) that functions as a wedge for anchoring the PC steel, it is possible to anchor various PC steel materials such as steel rods, steel wires, and steel strands.

[0009] In wedge-type anchoring, when the PC steel is gripped and pulled and anchored, slippage occurs between the male and female cones that function as wedges, and between the male cone and the PC steel, resulting in a loss of tensile force during anchoring. In contrast, the PC steel connection method disclosed in Patent Document 1 involves gripping and pulling the female cone, and then tightening the nut screwed onto the female cone to the bearing plate, thereby minimizing losses during anchoring. Furthermore, by connecting the PC steel to be placed in the newly constructed concrete member via the coupler attached to the female cone, it becomes possible to introduce prestress by using PC steel arranged to be continuous from the existing concrete member to the newly constructed concrete member. [Prior art documents] [Patent Documents]

[0010] [Patent Document 1] Patent No. 6083702 [Overview of the project] [Problems that the invention aims to solve]

[0011] However, the method for connecting PC steel materials disclosed in Patent Document 1 requires, as described above, "the step of screwing a tensioning member onto a male thread formed on the outer circumference of the female cone, pulling the tensioning member in the axial direction of the existing PC steel material, and tightening the anchoring nut so that it is in close contact with the bearing plate while the tensioning member is under tension." This anchoring nut (anchoring nut 4 in Figure 1 of Patent Document 1, etc.) is what is known as a ring nut, and the method for connecting PC steel materials disclosed in Patent Document 1 is merely a method of re-tensioning and anchoring the existing PC steel material using an anchoring device with this ring nut, then connecting the new PC steel material with a connector, covering it with a coupler sheath, and then constructing the new side. In terms of re-tensioning, anchoring, and connecting, Patent Document 1 can be said to disclose an effective means, but because a ring nut must be placed, the connector and coupler sheath inevitably become thicker, which is a problem.

[0012] In particular, in such reconstruction work, (as shown in Figure 13 later) connections of PC steel members are often required in areas where the spacing between PC steel members is narrow, or in areas where the member thickness is thin, such as floor slabs, where the reinforcing bars are densely arranged, resulting in work being carried out in an environment where the connections of PC steel members are extremely difficult. Therefore, there is a need for technology to make the connectors as thin as possible. Patent Document 1 cannot reach the technical concept of making the connectors as thin as possible as long as it uses ring nuts (anchoring nuts 4 in Figure 1 of Patent Document 1, etc.).

[0013] The present invention was developed in view of the above-mentioned problems of the prior art, and its objective is to provide a PC steel connector for connecting existing PC steel members, in which tension has already been introduced within existing concrete members, with newly installed PC steel members that are placed in newly constructed concrete members continuous with existing concrete members, and to provide a PC steel connector whose outer diameter is made as small as possible so that the PC steel members can be connected accurately and reliably even in narrow construction areas. Furthermore, the objective of the present invention is to provide a method for anchoring PC steel members, a method for connecting PC steel members, and a method for widening a bridge using such a PC steel connector. [Means for solving the problem]

[0014] To achieve the above objective, the PC steel connector relating to the curved surface of the present invention comprises the following technical means.

[0015] In other words, a PC steel connector according to a certain aspect of the present invention is a PC steel connector for connecting an existing primary PC steel member, which is fixed to an existing concrete structure with tensile force applied to it and is integral with the existing concrete structure due to adhesive force acting on its circumferential surface, and a newly installed secondary PC steel member, which is placed in a newly installed concrete structure and to which tensile force is applied, so as to transmit tensile force, wherein a part of the existing concrete structure is dismantled and the primary PC steel member protrudes from the end face of the structure, and the primary anchoring device includes a sleeve and a wedge that tensionably holds the protruding primary PC steel member, and the secondary PC steel member connected to the primary PC steel member tensionably The system includes a secondary anchoring device that securely holds the primary anchoring device, a connecting member that connects the primary anchoring device and the secondary anchoring device, and a correction jig that corrects the amount by which the primary PC steel material is pulled into the concrete structure due to a decrease in the adhesive force at the end of the primary PC steel material when the primary PC steel material is extended, wherein the correction jig includes a bearing plate that is substantially flat in shape and provided on the end face of the structure, and a fixing member that is substantially cylindrical in shape with an outer diameter less than or equal to the outer diameter of the sleeve and the connecting member, and has an insertion hole through which the primary PC steel material is inserted, and screws into the bearing plate, and the correction jig is characterized in that it corrects the amount by changing the screw state between the bearing plate and the fixing member.Here, the outer diameter of the fixing member is less than or equal to the outer diameter of the sleeve And being less than or equal to the outer diameter of the connecting member means being less than or equal to the maximum outer diameter of the connector before the coupler sheath is attached (often the sleeve and the connecting member are the maximum diameters before the coupler sheath is attached).

[0016] Preferably, the bearing plate is provided with a female screw hole having an inner diameter less than or equal to the outer diameter of the sleeve and the connecting member, the fixing member is provided with a male screw on its outer circumference that screws into the female screw hole and an insertion hole on its inner circumference for inserting the primary PC steel material, and the correction jig can be configured to correct the set amount by changing the screwing state between the female screw hole and the male screw.

[0017] More preferably, the fixing member is provided with a male screw on its outer circumference that screws into the female screw hole, and the end opposite to the bearing plate is provided with a locking portion which is a polygon whose vertex is located within the outer diameter of the male screw when viewed from the longitudinal direction of the PC steel material, instead of the male screw, and a rotating jig can be locked to the locking portion to rotate the fixing member and change the screwed state between the female screw hole and the male screw.

[0018] A PC steel connector according to another aspect of the present invention is a PC steel connector for connecting an existing primary PC steel member, which is fixed to an existing concrete structure with tensile force applied to it and is integral with the existing concrete structure due to adhesive force acting on its circumferential surface, and a newly installed secondary PC steel member, which is placed in a newly constructed concrete structure and to which tensile force is applied, so as to transmit tensile force, wherein a part of the existing concrete structure is dismantled and the primary PC steel member protrudes from the end face of the structure, a bearing plate is provided on the end face of the structure, and a primary anchoring device including a sleeve and a wedge that tensionably holds the protruding primary PC steel member, and the secondary PC steel member connected to the primary PC steel member The device includes a secondary anchoring device that holds tensionable, a connecting member that connects the primary anchoring device and the secondary anchoring device, and a correction jig that corrects the amount by which the primary PC steel material is pulled into the concrete structure due to a decrease in the adhesive force at the end of the primary PC steel material when the primary PC steel material is extended, wherein the correction jig is a ring nut with a female thread on its inner circumference that screws onto a male thread provided on the outer circumference of the sleeve on the bearing plate side, the outer diameter when the female thread of the ring nut is screwed onto the male thread of the sleeve is less than or equal to the outer diameter of the connecting member, and the correction jig corrects the amount by changing the screwed state between the sleeve and the ring nut. Here, the statement that the outer diameter when the female thread of the ring nut is screwed onto the male thread of the sleeve is less than or equal to the outer diameter of the connecting member means that it is less than or equal to the maximum outer diameter of the connector before the coupler sheath is attached (often the connecting member is the maximum diameter before the coupler sheath is attached).

[0019] Preferably, the sleeve has a small-diameter portion in which the male thread is provided at an outer diameter smaller than the outer diameter in which the wedge is located, and the sleeve is extended toward the bearing plate by the amount of the small-diameter portion so that the wedge is not located in the small-diameter portion, and the outer diameter when the female thread of the ring nut is screwed onto the male thread of the sleeve is less than or equal to the outer diameter of the connecting member.

[0020] A method for fixing PC steel members according to yet another aspect of the present invention is a method for fixing PC steel members, in which an existing primary PC steel member, which is fixed to an existing concrete structure with tensile force applied to it and is integral with the existing concrete structure due to adhesive force acting on its circumferential surface, and a newly installed secondary PC steel member, which is placed in a newly installed concrete structure and to which tensile force is applied, are fixed using the first three PC steel member connectors described above in order to connect them so as to transmit tensile force, the method comprising the steps of: dismantling a part of the existing concrete structure, removing the primary side fixing connector provided at the end of the existing PC steel member on the side connected to the newly installed PC steel member, and causing the primary side PC steel member to protrude from the end face of the structure; and inserting the protruding primary side PC steel member into the insertion hole of the fixing member and screwing the fixing member into place. The steps are: to provide the bearing plate on the end face of the frame; to position the primary anchoring device, including the sleeve and the wedge, on the protruding primary PC steel member; to connect the tensioning PC steel member, which replaces the secondary PC steel member, to the primary anchoring device via the secondary anchoring device and the connecting member; to connect the tensioning PC steel member to a jack and to install a reaction frame between the jack and the bearing plate; and to tension the tensioning PC steel member using the jack so that the primary PC steel member is tightened via the secondary anchoring device, the connecting member and the primary anchoring device. The method is characterized by including the steps of: correcting the gap created between the primary sleeve and the bearing plate to which the fixing member is screwed when the primary PC steel material is extended, the gap corresponding to the amount the primary PC steel material is pulled into the concrete structure due to a decrease in the adhesive force at the end of the primary PC steel material when the primary PC steel material is extended, by changing the screwed state between the bearing plate and the fixing member; removing the tensioning PC steel material, the secondary anchoring device, the connecting member, the jack and the reaction force frame; and protecting the end face of the primary sleeve opposite to the bearing plate.

[0021] A method for connecting PC steel members according to yet another aspect of the present invention is a method for connecting PC steel members, which connects an existing primary PC steel member, which is fixed to an existing concrete structure with tensile force applied to it and is integral with the existing concrete structure due to adhesive force acting on its circumferential surface, and a newly installed secondary PC steel member, which is placed in a newly constructed concrete structure and has tensile force applied to it, using the first three PC steel member connectors described above, in order to transmit tensile force, wherein a part of the existing concrete structure is removed The process involves removing the primary side anchoring device provided at the end of the existing PC steel material that connects to the newly installed PC steel material, and causing the primary side PC steel material to protrude from the end face of the structure; inserting the protruding primary side PC steel material into the insertion hole of the fixing member and providing the bearing plate, to which the fixing member is screwed, to the end face of the structure; arranging the primary side anchoring device, including the sleeve and the wedge, on the protruding primary side PC steel material; and arranging the tensioning PC steel material in place of the secondary side PC steel material, along with the secondary side anchoring device and The steps are: connecting the primary side anchoring member via the connecting member; connecting the tensioning PC steel member to the jack and installing a reaction frame between the jack and the bearing plate; and using the jack to tension the tensioning PC steel member so that the primary side PC steel member is tensioned via the secondary side anchoring member, the connecting member and the primary side anchoring member, and the gap created between the primary side sleeve and the bearing plate to which the fixing member is screwed, and when the primary side PC steel member is pushed out, the adhesion force at the end of the primary side PC steel member decreases. The steps include: correcting the gap corresponding to the amount the primary PC steel is pulled into the concrete structure by changing the screw engagement state between the bearing plate and the fixing member; removing the tensioning PC steel, the secondary anchoring device, the connecting member, the jack and the reaction frame; connecting the secondary PC steel to the primary anchoring device via the secondary anchoring device and the connecting member; and attaching a coupler sheath to the bearing plate that covers the fixing member, the primary anchoring device, the connecting member and the secondary anchoring device.The method is characterized by comprising the steps of: pouring concrete including the coupler sheath and the secondary PC steel to form a new concrete structure; and, after the poured concrete has hardened, tensioning the secondary PC steel.

[0022] A bridge widening method according to yet another aspect of the present invention is a bridge widening method which involves adding a new girder along an existing girder made of concrete, connecting the new PC steel members to be placed on the new girder to the existing lateral PC steel members that are placed on the existing girder and have adhesive forces acting on their circumferential surface to form an integral part with the concrete, using the first three PC steel member connectors described above, and introducing tensile force to integrate the new girder with the existing girder, the method comprising the steps of dismantling a part of the existing girder, removing the primary side anchoring device provided at the end of the existing PC steel member on the side connected to the new PC steel member, and making the primary side PC steel member protrude from the existing girder, and inserting the protruding primary side PC steel member into the insertion hole of the fixing member and screwing the fixing member in place The steps include: providing the bearing plate on the end face of the structure; arranging a primary anchoring device including the sleeve and the wedge on the protruding primary PC steel; connecting a tensioning PC steel in place of the secondary PC steel to the primary anchoring device via the secondary anchoring device and the connecting member; connecting the tensioning PC steel to a jack and installing a reaction frame between the jack and the bearing plate; and using the jack to tension the tensioning PC steel so that the primary PC steel is tensioned via the secondary anchoring device, the connecting member and the primary anchoring device, resulting in a gap between the primary sleeve and the bearing plate to which the fixing member is screwed, where the primary PC steel is pulled into the concrete structure due to a decrease in the adhesion force at the end of the primary PC steel when the primary PC steel is protruding. The method is characterized by comprising the steps of: correcting the gap corresponding to the amount of tension by changing the screw engagement state between the bearing plate and the fixing member; removing the tensioning PC steel, the secondary anchoring device, the connecting member, the jack and the reaction frame; connecting the secondary PC steel to the primary anchoring device via the secondary anchoring device and the connecting member; attaching a coupler sheath to the bearing plate that covers the fixing member, the primary anchoring device, the connecting member and the secondary anchoring device; pouring concrete, including the coupler sheath and the secondary PC steel, into the area forming the new girder or between a pre-formed new girder and the existing girder to form a girder connecting concrete structure as a new concrete structure; and tensioning the secondary PC steel after the poured concrete has hardened. [Effects of the Invention]

[0023] According to the connector for PC steel bars according to the present invention, it is a connector for PC steel bars that connects an existing PC steel bar in which a tensile force has already been introduced in an existing concrete member and a newly installed PC steel bar arranged in a newly installed concrete member that is continuous with the existing concrete member. The outer diameter of the connector is made as thin as possible so that the PC steel bars can be accurately and reliably connected even in a narrow construction site. Further, a method for fixing PC steel bars, a method for connecting PC steel bars, and a method for widening a bridge using such a connector for PC steel bars can be provided.

Brief Description of Drawings

[0024] [Figure 1] (A) A side view comparing the outer diameters of the coupler sheath type connector 1000 for PC steel bars according to an embodiment of the present invention and (B) a conventional ring nut type coupler sheath type connector 100 for PC steel bars (not the small diameter ring nut in the modification according to this embodiment). [Figure 2] In the connector 1000 for PC steel bars shown in FIG. 1(A), it is a side view showing a coupler sheath type connector 1002 for PC steel bars in which the configuration of the secondary fixing tool is changed to a wedge method. [Figure 3] In the connector 1002 for PC steel bars shown in FIG. 2, it is a side view showing a coupler sheath type connector 1004 for PC steel bars in which the primary fixing tool (wedge method) and the secondary fixing tool (wedge method) are changed to a joint 500 etc. (connection sleeve, C-type sleeve, connection ring) without using a plug 600. [Figure 4] It is a plan view of a pressure plate 180 provided with a female screw hole provided in a substantially central part, which constitutes a correction jig included in the connector for PC steel bars according to this embodiment. [Figure 5] It is a plan view of a fixing member 190 provided with a male screw on the outer periphery that is screwed into the female screw hole shown in FIG. 4, and adjusts the screwed state of the pressure plate 180 and the fixing member 190 to correct the set amount. It is a plan view of the fixing member 190 that constitutes a correction jig included in the connector for PC steel bars according to this embodiment. [Figure 6]This is a plan view illustrating a rotating jig 196 that uses the corner portion 194 of the fixing member 190 to rotate the fixing member 190 in order to change the screwed state between the bearing plate 180 and the fixing member 190. [Figure 7] This is a diagram (part 1) illustrating a method for anchoring PC steel materials and a method for connecting PC steel materials using the PC steel material connector according to this embodiment. [Figure 8] This is a diagram (part 2) illustrating a method for anchoring PC steel materials and a method for connecting PC steel materials using the PC steel material connector according to this embodiment. [Figure 9] This is Figure (3) illustrating a method for anchoring PC steel materials and a method for connecting PC steel materials using the PC steel material connector according to this embodiment. [Figure 10] This is a plan view of a bearing plate 181 according to a modified example of this embodiment. [Figure 11] This is a side view of a PC steel connector 1010 (small diameter ring nut type) according to a modified example of this embodiment. [Figure 12] This is a diagram (part 1) illustrating a bridge widening method using the PC steel connector according to this embodiment. [Figure 13] This is a diagram (part 2) illustrating a bridge widening method using the PC steel connector according to this embodiment. [Modes for carrying out the invention]

[0025] In the following, a coupler-sheath type PC steel connector 1000 according to an embodiment of the present invention will be described with reference to Figures 1 to 6, and a method for anchoring PC steel and connecting PC steel using this PC steel connector 1000 will be described with reference to Figures 7 to 9. Modifications according to this embodiment will be described with reference to Figures 10 and 11, and finally, a method for widening a bridge using this PC steel connector 1000 will be described with reference to Figures 12 and 13. In the following, the secondary side joint 500 may be simply referred to as the joint 500, and the center plug 600 may be simply referred to as the plug 600.

[0026] <PC Steel Bar Connector> Hereinafter, the PC steel bar connector 1000 according to the present embodiment will be described in detail. As shown in Fig. 1(A), the PC steel bar connector 1000 according to the present embodiment is fixed to an existing concrete housing C (which may be referred to as an existing concrete housing C hereinafter) in a state where a tensile force is introduced, and an adhesive force acts on the peripheral surface to be integrated with the existing concrete housing C. It connects an existing primary-side PC steel bar 10 and a newly installed secondary-side PC steel bar 20 arranged in a newly installed concrete housing NC (which may be referred to as a newly installed concrete housing NC hereinafter) and into which a tensile force is introduced so that the tensile force is transmitted. Although the detailed procedure will be described later, a part of the existing concrete housing C is disassembled so that the primary-side PC steel bar 10 protrudes from the housing end face (which may be described as exposed hereinafter in the same meaning), and a primary-side fixing tool including a sleeve 116 and a wedge 114 that hold the exposed primary-side PC steel bar 10 in a tensionable manner, a secondary-side fixing tool that holds the secondary-side PC steel bar 20 connected to the primary-side PC steel bar 10 in a tensionable manner, a connecting member that connects the primary-side fixing tool and the secondary-side fixing tool (here, a plug 600 that connects the primary-side sleeve 116 and the secondary-side compression grip 524), and a correction jig 170 that corrects the set amount by which the primary-side PC steel bar 10 is drawn into the concrete housing C due to a decrease in the adhesive force at the end of the primary-side PC steel bar 10 when the primary-side PC steel bar 10 is exposed. The PC steel bar connector 1000 includes these components. The primary-side PC steel bar 10 is coated with resin and covered with a sheath 12, and the secondary-side PC steel bar 20 is also coated with resin and covered with a sheath 22.

[0027] In the technical field to which this invention belongs, the set amount often refers to the amount by which the PC steel is pulled into the concrete structure C due to the wedge sinking into the sleeve as the PC steel returns (loosens) when the tensile load of the jack is released (unloaded) during the anchoring of the PC steel in the wedge method (resulting in a reduction in prestress (set loss)). However, in this invention, as described above, the set amount refers to the amount by which the primary PC steel 10 is pulled into the concrete structure C due to the decrease in the adhesion force at the end of the primary PC steel 10 when the primary PC steel 10 is exposed. Both set amounts appear in the connector as a gap t, which will be described later. Using the correction jig 170, this set amount is measured for the primary PC steel The set amount is adjusted to return the material 10 to its state before the adhesion strength at its end decreased.

[0028] As shown in Figures 4 to 6, the correction jig 170 includes a bearing plate 180 which is roughly flat and provided on the end face of the structure, and a fixing member 190 which is roughly cylindrical in shape, has an outer diameter less than or equal to the outer diameter of the primary sleeve 116 and the connecting member (plug 600 in this case), has an insertion hole 192 through which the primary PC steel material 10 is inserted, and screws into the bearing plate 180. The correction jig 170 corrects the set amount by changing the screwed state of the bearing plate 180 and the fixing member 190 (for example, using the rotating jig 196 shown in Figure 6). Here, Figure 4(A) is a cross-sectional view 4A-4A shown in Figure 4(B), and Figure 5(B) is a cross-sectional view 5B-5B shown in Figure 5(A). Furthermore, as shown in Figures 1(A) and 1(B), both the PC steel connector 1000 according to this embodiment and the conventional PC steel connector 100 are covered entirely by a coupler sheath 800. However, the outer diameter of the coupler sheath 800 is smaller for the PC steel connector 1000 according to this embodiment than for the conventional PC steel connector 100, making it preferable for the PC steel connector 1000 to be handled in narrower construction locations than for the conventional PC steel connector 100. Here, the statement that the outer diameter of the fixing member 190 is less than or equal to the outer diameter of the primary sleeve 116 and the connecting member (plug 600 in this case) means that it is less than or equal to the maximum outer diameter of the connector before the coupler sheath is attached (the sleeve and connecting member (plug 600, etc.) are often the maximum diameter before the coupler sheath is attached).

[0029] Here, the coupler-sheath type PC steel connector 1000 according to this embodiment has been described as having a compression grip 524 and a C-type sleeve 526 as secondary-side anchoring members. However, as shown in Figure 2, the secondary-side anchoring member may be a wedge-type PC steel connector 1002, or as shown in Figure 3, a PC steel connector 1004 may be used in which the primary-side sleeve 116 is screwed together with the secondary-side sleeve 126 to connect to the secondary-side joint 500 (as a connecting member) without using a plug 600. As shown in Figure 3, in the secondary-side anchoring member, the secondary-side wedge 124 may have its longitudinal movement of the secondary-side PC steel 20 restricted by a wedge retainer 128. Although not shown, a PC steel connector may also be used in which the primary-side sleeve 116 is screwed together with the compression grip 524 to connect to the C-type sleeve (as a connecting member) or the like without using a plug 600 as shown in Figure 1(A).

[0030] As described above, connectors 1000, 1002, and 1004 will be described in detail as PC steel material connectors according to this embodiment (connector 1000 will be used to represent the other connectors 1002 and 1004 when explaining common features, but connector 1010 according to the second modified example will be distinguished because it has different features from these three), but the connectors according to the present invention are not limited to these. The PC steel connector according to the present invention is characterized in that it includes a correction jig 170 that corrects the amount by which the primary PC steel 10 is pulled into the concrete structure C due to a decrease in the adhesive force at the end of the primary PC steel 10 when the primary PC steel 10 is exposed, and the outer diameter of the substantially cylindrical fixing member 190 constituting this correction jig is less than or equal to the outer diameter of the primary sleeve 116 and the connecting member (in this case, the plug 600), so that the outer diameter of the coupler sheath type PC steel connector 1000 (outer diameter of the coupler sheath 800) is smaller than that of the conventional coupler sheath type PC steel connector 100 (outer diameter of the coupler sheath 800) using a normal bearing plate 18 and ring nut 19 as shown in Figure 1(B). The outer diameter (which is the outer diameter of the coupler sheath 800) φD(1) of the PC steel connector 1000 (which includes a correction jig 170 that includes a bearing plate 180 and a fixing member 190) according to this embodiment shown in Figure 1(A) is smaller than the outer diameter (which is the outer diameter of the coupler sheath 800) φD(2) of the conventional PC steel connector 100 (which includes a bearing plate 18 and a ring nut 19) shown in Figure 1(B).

[0031] More specifically, the coupler sheath type PC steel connector 1000 according to this embodiment is as shown in Figures 4 and 5, and the bearing plate 180 consists of a primary sleeve 116 and a connecting member ( Here, the bearing plate 180 has an internal diameter of female thread 182 with an internal diameter less than or equal to the external diameter of the plug 600), and a female thread 182F is provided on the internal circumference of this female thread. The fixing member 190 has a male thread 190M on its external circumference that screws into the female thread 182F, and an insertion hole 192 on its internal circumference through which the primary PC steel material 10 is inserted. This correction jig corrects the set amount by changing the screw engagement state between the female thread 182F of the female thread hole 182 in the bearing plate 180 and the male thread 190M on the external circumference of the fixing member 190. The holes 184 provided at the four corners of the bearing plate 180 are holes (sometimes referred to as female thread holes 184) for attaching the coupler sheath 800 (for example, with a female thread on the internal circumference).

[0032] More specifically, the coupler sheath type PC steel connector 1000 according to this embodiment, as shown in Figures 4 to 6, has a fixing member 190 with a male screw 190M on its outer circumference that screws into a female screw 182F provided on the inner circumference of a female screw hole 182, and the end 193 opposite to the bearing plate 180 has a locking part 194 made of a polygon (here a hexagon) whose vertex is located within the outer diameter of the male screw 190M when viewed from the longitudinal direction of the PC steel. Then, using the rotating jig 196 shown in Figure 6, the fitting part 199 of the rotating jig 196 is locked into the locking part 194 (the operator holds the handle part 198 by hand) and the fixing member 190 is rotated to change the screwing state between the female screw hole 192F and the male screw 190M and correct the set amount.

[0033] Regarding the figures referred to in the previous descriptions and the figures to be referred to in the following descriptions, for the sake of easy understanding of the present invention, basically, they are schematic diagrams in which detailed structures are omitted. There are cases where parts that should be represented by the outer shape rather than the inside are represented as if the inside is seen through, cases where parts that should be represented by the cross-section rather than the outer shape are represented by the outer shape, cases where parts that should be represented by the outer shape rather than the cross-section are represented by the cross-section, cases where hidden lines are represented by solid lines rather than dotted lines, and cases where the same members are given different hatchings. Here, the coupler sheath type PC steel material connector 1000 according to the present embodiment will be described in detail including the connector 1002 and the connector 1004 as described above (when explaining the common points, the connector 1000 represents the other connectors 1002 and 1004). However, the PC steel material connector according to the present invention is not limited to these (for example, there is a PC steel material connector 1010 according to the second modification example).

[0034] <Fixing method and connecting method of PC steel materials> Regarding the fixing method and connecting method of PC steel materials using the coupler sheath type PC steel material connector 1000 according to the present embodiment, it will be described in detail with reference to FIGS. 7 to 9.

[0035] The fixing method of PC steel materials using the coupler sheath type PC steel material connector 1000 according to the present embodiment is, as described above, fixed to the existing concrete structure C in a state where tensile force is introduced, and an existing primary side PC steel material 10 that is integrated with the existing concrete structure C with an adhesive force acting on its circumferential surface, and a new secondary side PC steel material 20 that is arranged in the new concrete structure NC and tensile force is introduced are connected so that the tensile force is transmitted.

[0036] FIG. 7(A) shows the existing primary side PC steel material 10 that is fixed to the existing concrete structure C in a state where tensile force is introduced and is integrated with the existing concrete structure C with an adhesive force acting on the circumferential surface of the PC steel material.

[0037] As shown in Figure 7(B), a portion of the existing concrete structure C is demolished, and the primary side anchoring devices (for example, the primary side sleeve 116 and wedge 114) provided at the end of the existing PC steel member 10 that connects to the new PC steel member 20 are removed, and the primary side PC steel member 10 is made to protrude from the end face of the structure (existing concrete structure C) (protrusion step).

[0038] Next, as shown in Figure 7(C), the protruding (exposed) primary PC steel member 10 is inserted through the insertion hole 192 of the fixing member 190, and the bearing plate 180 to which the fixing member 190 is screwed is attached to the structure (pre-existing) The bearing plate is installed on the end face of the concrete structure C (step for attaching the bearing plate with the fixing member screwed in). At this time, it is preferable to screw the fixing member 190 all the way to the end face of the bearing plate 180 on the side of the existing concrete structure C (this allows for larger gaps t to be accommodated).

[0039] Next, as shown in Figure 7(D), the primary side anchoring device, including the sleeve 116 and wedge 114, is placed on the protruding (exposed) primary side PC steel material 10 (anchoring device mounting step). The secondary side inner surface of the sleeve 116 is provided with a female thread 116F that engages with the male thread provided on the outer circumference of the plug 600.

[0040] Next, as shown in Figure 8(A), the tensioning PC steel member 21, which replaces the secondary PC steel member 20, is connected to the primary anchoring member via a secondary anchoring device (here, a compression grip 524 and a C-type sleeve 526) and a connecting member (here, a plug 600) (connection step). The female thread provided on the inner surface of the primary side of the C-type sleeve 526 and the male thread provided on the outer circumference of the plug 600 are screwed together. In this connection step, the primary sleeve 116 and the secondary C-type sleeve 526 are connected via the connecting member, the plug 600. The connecting device at this time is the PC steel member connector 1001 (not covered by the coupler sheath 800). Furthermore, the tensioning PC steel member 21, which is connected to the primary PC steel member 10 by the PC steel member connector 1001, is connected to the (center hole) jack 200, and a reaction force frame (chair) 2010 is installed between the jack 200 and the bearing plate 180 (jack installation step).

[0041] Next, as shown in Figure 8(B), the tensioning PC steel members 21 are tensioned in the direction of the white arrows using the jack 200, and the primary PC members 10 are tensioned via the secondary anchoring devices (compression grips 524, C-type sleeves 526), ​​connecting members (plugs 600), and primary anchoring devices (primary sleeves 116, primary wedges 114), creating a gap t between the primary sleeve 116 and the bearing plate 180 to which the fixing member 190 is screwed. This gap t corresponds to the amount by which the primary PC steel members 10 are pulled into the existing concrete structure C due to the decrease in the adhesion force at the end of the primary PC steel members 10 when the primary PC steel members 10 are exposed (jack tensioning step).

[0042] Next, as shown in Figure 8(C), the gap t generated in the previous step, the jack tensioning step (which may be referred to as the gap t corresponding to the set amount below), is corrected by changing the screw engagement state between the bearing plate 180 and the fixing member 190 (correction step). This is done by rotating the fixing member 190 using the rotating jig 196 and bringing it into contact with the primary end face of the fixing member 190 (the end face on the locking portion 194 side), thereby correcting the set amount. This will be explained in detail.

[0043] In this case, as shown in Figure 6, the fitting portion 199 of the rotating jig 196 is locked into the locking portion 194 (the operator holds the handle portion 198 by hand) and the fixing member 190 is rotated to change the screwed state between the female screw hole 192F and the male screw 190M. In this case, although the reaction force frame 210 is not open in the vertical direction in Figure 8, it is open in the horizontal direction, so the fitting portion 199 of the rotating jig 196 is inserted into the fixing member 190 from the left or right direction through the gap in the reaction force frame 210, and the fitting portion 199 of the rotating jig 196 is locked into the locking portion 194 (the operator holds the handle portion 198 by hand) and the fixing member 190 is rotated. Furthermore, since the reaction force frame 210 is open in either the vertical or horizontal direction (in Figure 6 it is open in the vertical direction, and in Figure 8 it is open in the horizontal direction), the fitting portion 199 of the rotating jig 196 can be inserted from the open direction, and the locking portion 194 of the fixing member 190 can be inserted from the gap (in the open direction) of the reaction force frame 210, thereby allowing the fixing member 190 to rotate.

[0044] In this way, the fixing member 190 is rotated so that the female thread 182F of the bearing plate 180 and the fixing member 19 The screw engagement state with the male screw 190M is changed to shift the gap t shown in Figure 8(B) to the gap t shown in Figure 8(C). Here, the state shown in Figure 8(B) is a state in which a gap t exists between the bearing plate 180 and the fixing member 190 and the primary sleeve 116 (these are integrated by screwing) due to the set amount, and the set amount has not been corrected. On the other hand, the state shown in Figure 8(C) is a state in which the fixing member 190 is rotated to move the fixing member 190 away from the bearing plate 180 to the secondary side in order to correct the set amount, so the bearing plate 180 and the fixing member 190 are integrated by screwing (although a gap t exists), and the end face of the primary sleeve 116 on the bearing plate 180 side is in contact with the end face of the fixing member 190, and the set amount has been corrected (even if the tensile load of the jack 200 is released (unloaded), the primary PC steel member 10 is not pulled into the existing concrete housing C).

[0045] Next, as shown in Figure 9(A), the tensioning PC steel members 21, secondary anchoring devices (here, compression grips 524 and C-type sleeves 526), ​​connecting members (here, plugs 600), jacks 200, and reaction frame 210 are removed, and the end face of the primary sleeve 116 opposite to the bearing plate 180 is protected (curing step). At this time, it is also preferable to seal the primary sleeve 116 with a male threaded cap 118 using the female thread 116F. Furthermore, it is also preferable to seal it with resin or the like for long-term protection before sealing it with the cap 118. This is because the widening work shown in Figure 9(B) may be carried out more than ten years to several decades later. This concludes the method for anchoring PC steel bars. The method for connecting PC steel bars includes the following steps in addition to the anchoring method described above.

[0046] As shown in Figure 9(B), the threaded cap 118 is removed and the secondary PC steel member 20 is connected to the primary anchoring member (here, the sleeve 116 and wedge 114) via the secondary anchoring member (here, the compression grip 524 and C-shaped sleeve 526) and the connecting member (here, the plug 600) (connection step).

[0047] Next, as shown in Figure 9(C), the coupler sheaths 800 are attached to the bearing plate 180 using the female screw holes 184 provided at the four corners of the bearing plate 180 so as to cover the fixing member 190, the primary fixing device (here, the sleeve 116 and wedge 114), the connecting member (here, the plug 600), and the secondary fixing device (here, the compression grip 524 and C-shaped sleeve 526) (coupler sheath attachment step). At this time, the coupler sheaths 800 are filled with resin or the like.

[0048] Next, as shown in Figure 9(D), concrete is poured including the coupler sheath 800 and the secondary PC steel members 20 to form the new concrete enclosure NC (new concrete pouring). After the poured new concrete enclosure NC has hardened, the secondary PC steel members are tensioned (secondary tensioning step). This secondary tensioning step is carried out using known techniques. This concludes the method of connecting PC steel members, including the method of anchoring the PC steel members.

[0049] Two modified examples of the PC steel connector 1000 described above will be explained with reference to Figures 10 and 11. First, the first modified example shown in Figure 10 is a modified example of the bearing plate 180. While the bearing plate 180 shown in Figure 4(B) had a roughly square shape when viewed from the longitudinal direction of the PC steel member, the bearing plate 181 shown in Figure 10(B) may have a rectangular shape instead of being roughly square when viewed from the longitudinal direction of the PC steel member. Note that Figure 10(A) is the 10A-10A section line in Figure 10(B).

[0050] Next, a second modified example will be described with reference to Figure 11. The correction jig in the PC steel connector 1000 described above has a female thread 182F in the female screw hole 182 of the bearing plate 180, The set amount was corrected by changing the screw engagement state with the male thread 190M on the outer circumference of the fixing member 190, but the PC steel connector 1010, which is the second modified example shown in Figure 11, does not correct the set amount in this way. The PC steel connector 1010 will be described in detail below, but the same reference numerals are used for components common to both Figure 1(A) and Figure 11, and detailed explanations of these components will not be repeated here. Note that the bearing plate 18 in Figure 11 is merely a normal bearing plate (without female screw holes 182).

[0051] The correction jig is a ring nut 191 with a female thread on its inner circumference that screws onto a male thread on the outer circumference of the primary sleeve 117 on the bearing plate 18 side. When the female thread of the ring nut 191 is screwed onto the male thread of the sleeve 117, the outer diameter is less than or equal to the outer diameter of the connecting member (in this case, the plug 600 and C-type sleeve 526, excluding the small diameter portion 119 of the sleeve 117). This is achieved by providing a small diameter portion 119 on the bearing plate 18 side of the primary sleeve 117, which is made thinner by machining, and providing a male thread on this small diameter portion. This is achieved by reducing both the inner and outer diameters of the ring nut 191 while maintaining its wall thickness (while maintaining its strength). Here, the outer diameter when the female thread of the ring nut 191 is screwed onto the male thread of the sleeve 117 being less than or equal to the outer diameter of the connecting member (in this case, the plug 600 and the C-type sleeve 526, excluding the small diameter portion 119 of the sleeve 117) means that it is less than or equal to the maximum outer diameter of the connector before the coupler sheath is attached (the connecting member is often the maximum diameter before the coupler sheath is attached).

[0052] More preferably, as shown in Figure 11, the PC steel connector 1010 includes a small-diameter portion 119 in the sleeve 117, which has a male thread on an outer diameter smaller than the outer diameter where the wedge 114 is located. Furthermore, (to prevent crushing of the small-diameter portion 119 by the wedge 114) the sleeve 117 is extended toward the bearing plate 180 by the amount of the small-diameter portion 119 so that the wedge 114 is not located in the small-diameter portion 119. When the female thread of the ring nut 191 is screwed onto the male thread (small-diameter portion 119) of the sleeve 117, the outer diameter is less than or equal to the outer diameter of the connecting member (in this case, the plug 600 and C-type sleeve 526, excluding the small-diameter portion 119 of the sleeve 117).

[0053] In this PC steel connector 1010, the correction jig, the ring nut 191, corrects the set amount by changing the screwed state between the sleeve 117 and the ring nut 191. As mentioned above, although the inner and outer diameters of the ring nut 191 differ from those of a known ordinary ring nut, the other components are the same, and therefore the method of use (method of correcting the set amount) is also the same. In the PC steel connector 1010 according to this modified example, a male thread for screwing the ring nut 191 into the small diameter portion 119 of the sleeve 117 is provided, so an outer diameter φD(1) is achieved that is smaller than the outer diameter φD(2) with the coupler sheath attached compared to the PC steel connector 100 using a known ordinary ring nut 19 shown in Figure 1(B). The outer diameter of the coupler sheath type PC steel connector 1010 is smaller than the outer diameter of the conventional coupler sheath type PC steel connector 100, making the PC steel connector 1010 preferable for handling in narrow construction areas.

[0054] <Methods for widening bridges> Finally, with reference to Figures 12 and 13, a bridge widening method using the coupler-sheath type PC steel connector 1000 according to this embodiment will be described. As described above, the bridge widening method is carried out after connecting the existing primary PC steel, which is fixed to the existing concrete structure C with tensile force applied and is integrated with the existing concrete structure C due to adhesive force acting on its circumferential surface, and the newly installed secondary PC steel, which is placed in the new concrete structure NC and to which tensile force is applied, so that tensile force is transmitted. Note that in Figures 12 and 13, some of the reference numerals in Figures 1 to 9 described above are not shown because it would be difficult to distinguish the numerals, so please refer to the reference numerals in Figures 1 to 9.

[0055] The bridge widening method using the PC steel connector 1000 involves adding a new girder along the existing concrete girder, connecting the new PC steel to be placed in the new girder to the existing lateral PC steel, which is placed in the existing girder and has adhesive force acting on its circumferential surface, using the PC steel connector 1000 (excluding the connector 1010 related to the second modified example), and introducing tensile force to integrate the new girder with the existing girder.

[0056] Referring to Figure 12(A), the state of the bridge before widening will be explained. As shown in Figure 12(A), this bridge 801 is formed by arranging multiple (in this case, four) precast concrete girders 810, which have a T-shaped cross-section, in the width direction. Existing PC steel members 10 are embedded in the deck slab portion 812 of these existing girders 810 with tension applied. These existing PC steel members 10 are anchored by anchoring devices (anchoring device 840S on the side that is not widened, and anchoring device 840E on the side that is widened) located on both sides of the bridge 801 (near both ends of the deck slab portion 812 of the girders 810). Therefore, both ends of the PC steel members 10 are anchored by wedge-type anchoring devices 840S and 840E (combination of sleeve and wedge) so that a reaction force acts on the existing girders 810 via bearing plates. Furthermore, curbs 830 are formed on both sides of the bridge 801, and the existing wedge-type anchoring devices 840S and 840E for the PC steel members 10 are embedded in the concrete forming the curbs 830 (from the standpoint of preventing corrosion).

[0057] Furthermore, infill concrete CC is poured into the gaps in the width direction of the concrete girders 810, and the existing concrete casing C is formed by the girders 810 (four legs in this case), which are precast members, and the infill concrete CC (three locations in this case). The existing PC steel members 10 are inserted into sheaths 12 that are arranged in the width direction of the floor slab 812, and adhere to the grout filled in the sheaths 12, becoming integrated with the existing concrete casing C and applying tension to the existing concrete casing C.

[0058] As shown in Figure 12(B), a portion of the existing girder 810 is dismantled, and the primary side anchoring device 840E (in this case, the anchoring device 840E embedded in the curb 830 on the far right of the drawing) provided at the end of the existing PC steel member 10 that connects to the new PC steel member 20 is removed, and the primary side PC steel member 10 is made to protrude from the existing girder. Note that the state shown in Figure 12(B) corresponds to the state shown in Figure 7(B).

[0059] Next, as shown in Figure 12(C), the protruding primary PC steel member 10 is inserted through the insertion hole 192 of the fixing member 190 (which constitutes the correction jig 170), and the bearing plate 180 (which constitutes the correction jig 170), to which the fixing member 190 is screwed, is provided on the end face of the structure.

[0060] A wedge-type primary anchoring device including a sleeve 116 and a wedge 114 is placed on the protruding primary PC steel member 10, and a tensioning PC steel member 21, which replaces the secondary PC steel member 20, is connected to the primary anchoring device (here, the sleeve 116 and wedge 114) via a secondary anchoring device (here, a compression grip 524 and a C-shaped sleeve 526) and a connecting member (here, a plug 600) (forming a connecting device 1001), and the tensioning PC steel member 21 is connected to the jack 200, and a reaction force frame 210 is installed between the jack 200 and the bearing plate 180.

[0061] The tensioning PC steel members 21 are tensioned using the jack 200, and the primary PC steel members 10 are tensioned via the secondary anchoring device (here, the compression grip 524 and the C-shaped sleeve 526), ​​the connecting member (here, the plug 600), and the primary anchoring device, and the gap t created between the primary sleeve and the bearing plate to which the fixing member is screwed, and when the primary PC steel members 10 are exposed, the adhesion force at the end of the primary PC steel members 10 decreases, causing the primary PC steel members 10 to be in the same position as the existing PC steel members The gap t corresponding to the amount of material pulled into the concrete structure C is corrected by changing the screw engagement state between the bearing plate 180 and the fixing member 190. Note that the state shown in Figure 12(C) corresponds to the states shown in Figures 7(C) to 8(C).

[0062] Subsequently, although not shown in the figures, it is also preferable to remove the tensioning PC steel 21, secondary anchoring devices (here, compression grips 524 and C-type sleeves 526), ​​connecting members (here, plugs 600), jacks 200 and reaction frame 210, and seal them with a male-threaded cap 118 using the female thread 116F of the primary-side sleeve 116, as shown in Figure 9(A).

[0063] Next, as shown in Figure 12(D), the secondary PC steel members 20 for the newly installed girder are connected to the primary anchorage members via secondary anchorage members (in this case, compression grips 524 and C-type sleeves 526) and connecting members (in this case, plugs 600). Then, the fixing members 190, the primary anchorage members, connecting members, and coupler sheaths 800 covering the secondary anchorage members are attached to the bearing plate 180. This connects the existing primary anchorage members and the newly installed secondary anchorage members using the PC steel member connectors 100.

[0064] Two new girders 811 are installed in parallel with the existing girder 810. The new secondary PC steel members 20 are inserted into the sheaths 22 embedded in the new girders 811, and anchoring devices 840F are attached to the parts that will become the side edges when widened to secure them to the new girders 811. Then, as shown in Figure 12(D), new concrete NC is poured into the slab sections between the existing girders 810 and the new girders 811, and between the new girders 811, to connect all the girders 810 and 811.

[0065] In other words, concrete is poured as a new concrete structure NC (including the coupler sheath type PC steel connector 1000 and the secondary PC steel 20 (embedded in the new concrete structure NC) in the area where the new girder 811 is formed (between the new girders 811 and the new girders 811) or between the pre-formed new girder 811 and the existing girder 810, thereby forming the girder connecting concrete structure.

[0066] After the poured concrete has hardened, the secondary PC steel members 20 are tensioned using jacks 201 and then anchored with anchoring devices 840F. Note that the conditions shown in Figures 12(D) to 12(F) correspond to the conditions shown in Figures 9(B) to 9(D).

[0067] Furthermore, with reference to Figure 13, a part of the bridge widening method will be explained. Note that Figure 13(A) corresponds to Figure 7(A), Figure 13(B) corresponds to Figure 7(B), Figure 13(C) corresponds to Figures 7(C) to 8(C), and Figure 13(D) corresponds to Figures 9(B) to 9(D). Note that, unlike in Figure 12, it is assumed here that the primary PC steel members 10 are inserted through the entire existing concrete casing C and tensioned to generate prestress in the existing concrete casing C.

[0068] As shown in Figure 13(A), the existing concrete casing C is chipped away, including the anchoring device 840E at the start of the bridge widening. Note that the anchoring device 840E does not need to be embedded in the concrete, but (because the PC steel is often cut short on the back side of the anchoring device 840E) the primary PC steel 10, including the anchoring device 840E, must protrude from the end of the primary PC steel 10 by the length required for the extension work. As shown in Figure 13(B), a temporary column 820 is provided to support the existing concrete enclosure C, causing the primary PC steel member 10 to protrude.

[0069] As shown in Figure 13(C), a PC steel connector 1001 equipped with a bearing plate 180 and a fixing member 190, which are correction jigs 170, is used to connect the protruding primary PC steel and the tensioning PC steel. When the primary PC steel member 10 is tensioned using the reaction frame 210 and jack 200 after connecting member 21, a gap t occurs, so the set amount is corrected using a correction jig.

[0070] As shown in Figure 13(D), the primary PC steel members 10 that tension the existing concrete enclosure C (with corrected set amounts) and the secondary PC steel members 20 that tension the new concrete enclosure NC are connected with a coupler-sheath type PC steel connector 1000 fitted with a coupler-sheath 800, and the new concrete is poured to form the new concrete enclosure NC. Once the poured new concrete enclosure NC has completely hardened, the primary PC steel members 10 and the secondary PC steel members 20 connected via the coupler-sheath type PC steel connector 1000 are tensioned using a jack 201 by a known conventional tensioning method and fixed with an anchoring device 840F. After this, it is also preferable (from the viewpoint of preventing corrosion) to embed the anchoring device 840F in the concrete forming the curb 830.

[0071] The bridge widening method described with reference to Figure 12 (and Figure 13) allows widening work to be carried out while maintaining the widthwise prestress acting on the existing girder 810. Specifically, the pulling of the primary PC steel members into the existing concrete housing C (reduction of prestress) caused by the removal of the anchoring devices that apply prestress to the existing girder 810 can be corrected with a correction jig, allowing widening work to be carried out while maintaining the predetermined prestress on the existing girder 810. Furthermore, the restriction on the use of the existing bridge 801 due to the widening work can be minimized. In addition, since the secondary PC steel members 20 placed on the new girder 811 can be connected to the existing primary PC steel members 10 placed on the existing girder 810 with a connector (equipped with a correction jig) to introduce tensile force, there is no need to drill holes in the existing girder 810, which suppresses cost increases and allows the bridge to be widened without damaging the existing girder 810. Furthermore, because the connector (equipped with a correction jig) has a small diameter, its outer diameter remains thin even when a coupler sheath is attached. This allows for easy handling even in narrow construction areas as shown in Figure 13, and enables accurate and reliable connection of PC steel materials.

[0072] As described above, the PC steel connector according to this embodiment connects existing PC steel members, in which tension has already been introduced within an existing concrete member, to newly installed PC steel members that are placed in a newly constructed concrete member continuous with the existing concrete member. The connector's outer diameter is made as small as possible, allowing for accurate and reliable connection of PC steel members even in narrow construction areas. Furthermore, a method for anchoring PC steel members, a method for connecting PC steel members, and a method for widening a bridge can be provided using such a PC steel connector.

[0073] It should be noted that the embodiments disclosed herein are illustrative and not restrictive in all respects. The scope of the present invention is indicated by the claims rather than by the foregoing description, and all modifications within the meaning and scope equivalent to the claims are intended to be included. [Industrial applicability]

[0074] The present invention is preferable as a connector for prestressed concrete (PC) steel bars that connects existing PC steel bars, in which tension has already been introduced within an existing concrete member, to newly installed PC steel bars that are placed in a newly constructed concrete member continuous with the existing concrete member. It is particularly preferable in that the outer diameter of the connector can be made as small as possible, allowing for accurate and reliable connection of PC steel bars even in narrow construction areas. It is even more preferable in that such a PC steel bar connector can be applied to methods for anchoring PC steel bars, methods for connecting PC steel bars, and methods for widening bridges. [Explanation of Symbols]

[0075] 10, 20 PC steel material 114, 124 wedge 116, 126 sleeves 170 Correction jig 180 bearing plate 190 Fixing member 196 Rotary fixture 200, 201 Jacks 210 Reaction force stand (chair) 524 Compression Grip 526 C-type sleeve 600 Plug (connecting component) 800 Coupler Sheath 1000 PC steel connector (connector)

Claims

1. A PC steel connector for connecting an existing primary PC steel member, which is fixed to an existing concrete structure with tensile force applied to it and is integrated with the existing concrete structure due to adhesive force acting on its circumferential surface, and a newly installed secondary PC steel member, which is placed in a newly constructed concrete structure and has tensile force applied to it, so as to transmit tensile force, A portion of the existing concrete structure is demolished, and the primary PC steel material protrudes from the end face of the structure. A primary anchoring device including a sleeve and a wedge that tensionably hold the protruding primary PC steel material, A secondary anchoring device that tensions and holds the secondary PC steel material connected to the primary PC steel material, A connecting member that connects the primary side fixing device and the secondary side fixing device, The system includes a correction jig for correcting the amount by which the primary PC steel is pulled into the concrete structure due to a decrease in the adhesion force at the end of the primary PC steel when the primary PC steel is extended, The correction jig is, A bearing plate having a roughly flat shape and provided on the end face of the frame, It includes a fixing member that is substantially cylindrical in shape, has an outer diameter less than or equal to the outer diameter of the sleeve and the connecting member, has an insertion hole for inserting the primary PC steel material, and screws into the bearing plate, The correction jig is a connector characterized by correcting the set amount by changing the screwed state between the bearing plate and the fixing member.

2. The bearing plate is provided with a female screw hole having an inner diameter less than or equal to the outer diameter of the sleeve and the connecting member. The fixing member has a male screw on its outer circumference that screws into the female screw hole, and an insertion hole on its inner circumference through which the primary PC steel material is inserted. The connector according to claim 1, characterized in that the correction jig corrects the set amount by changing the screwing state between the female screw hole and the male screw.

3. The fixing member is provided with a male screw on its outer circumference that screws into the female screw hole, and the end opposite to the bearing plate is provided with a locking portion which is a polygon whose vertex is located within the outer diameter of the male screw when viewed from the longitudinal direction of the PC steel material, instead of the male screw. The connector according to claim 2, characterized in that a rotating jig is locked to the locking portion, causing the fixing member to rotate and changing the screwed state between the female screw hole and the male screw.

4. A PC steel connector for connecting an existing primary PC steel member, which is fixed to an existing concrete structure with tensile force applied to it and is integrated with the existing concrete structure due to adhesive force acting on its circumferential surface, and a newly installed secondary PC steel member, which is placed in a newly constructed concrete structure and has tensile force applied to it, so as to transmit tensile force, A portion of the existing concrete structure is demolished, and the primary PC steel members protrude from the end face of the structure, and a bearing plate is provided on the end face of the structure. A primary anchoring device including a sleeve and a wedge that tensionably hold the protruding primary PC steel material, A secondary anchoring device that tensions and holds the secondary PC steel material connected to the primary PC steel material, A connecting member that connects the primary side fixing device and the secondary side fixing device, The system includes a correction jig for correcting the amount by which the primary PC steel is pulled into the concrete structure due to a decrease in the adhesion force at the end of the primary PC steel when the primary PC steel is extended, The correction jig is screwed onto a male thread provided on the outer circumference of the sleeve on the bearing plate side. A ring nut having a female thread on its inner circumference, When the female thread of the ring nut is screwed onto the male thread of the sleeve, the outer diameter is less than or equal to the outer diameter of the connecting member. The correction jig is a connector characterized by correcting the set amount by changing the screwed state between the sleeve and the ring nut.

5. The connector according to claim 4, characterized in that the sleeve has a small diameter portion on which the male thread is provided, with an outer diameter smaller than the outer diameter on which the wedge is located, the sleeve is extended toward the bearing plate by the amount of the small diameter portion so that the wedge is not located in the small diameter portion, and the outer diameter when the female thread of the ring nut is screwed onto the male thread of the sleeve is less than or equal to the outer diameter of the connecting member.

6. A method for fixing PC steel, comprising fixing an existing primary PC steel member, which is fixed to an existing concrete structure with tensile force applied to it and is integral with the existing concrete structure due to adhesive force acting on its circumferential surface, and a newly installed secondary PC steel member, which is placed in a newly constructed concrete structure and to which tensile force is applied, using a connector according to any one of claims 1 to 3, in order to connect the primary PC steel member so as to transmit tensile force, The steps include: demolishing a portion of the existing concrete structure, removing the primary anchoring device provided at the end of the existing PC steel material that connects to the newly installed PC steel material, and causing the primary PC steel material to protrude from the end face of the structure; The steps include inserting the protruding primary PC steel member into the insertion hole of the fixing member and attaching the bearing plate, to which the fixing member is screwed, to the end face of the structure, The steps include: arranging the primary side anchoring device, which includes the sleeve and the wedge, on the protruding primary side PC steel material; The steps include connecting the tensioning PC steel material, which replaces the secondary PC steel material, to the primary anchoring device via the secondary anchoring device and the connecting member, The steps include connecting the tensioning PC steel member to the jack and installing a reaction frame between the jack and the bearing plate, The process involves using the jack to tension the tensioning PC steel material, thereby tensioning the primary PC steel material via the secondary anchoring device, the connecting member, and the primary anchoring device, and correcting the gap between the bearing plate, which is screwed with the primary sleeve and the fixing member, by changing the screwed state between the bearing plate and the fixing member, which corresponds to the amount the primary PC steel material is pulled into the concrete structure due to a decrease in the adhesive force at the end of the primary PC steel material when the primary PC steel material is protruding. The steps include removing the tensioning PC steel material, the secondary anchoring device, the connecting member, the jack, and the reaction frame, A method for anchoring PC steel material, characterized by including the step of protecting the end face of the primary sleeve opposite to the bearing plate.

7. A method for connecting PC steel members, comprising connecting an existing primary PC steel member, which is fixed to an existing concrete structure with tensile force applied to it and is integral with the existing concrete structure due to adhesive force acting on its circumferential surface, and a newly installed secondary PC steel member, which is placed in a newly constructed concrete structure and to which tensile force is applied, using a connector described in any one of claims 1 to 3, in order to transmit tensile force, wherein the connection is made between the primary PC steel member and the secondary PC steel member. The steps include: demolishing a portion of the existing concrete structure, removing the primary anchoring device provided at the end of the existing PC steel material that connects to the newly installed PC steel material, and causing the primary PC steel material to protrude from the end face of the structure; The steps include inserting the protruding primary PC steel member into the insertion hole of the fixing member and attaching the bearing plate, to which the fixing member is screwed, to the end face of the structure, The primary side anchoring of the protruding primary side PC steel material includes the sleeve and the wedge. The step of arranging the ingredients, The steps include connecting the tensioning PC steel material, which replaces the secondary PC steel material, to the primary anchoring device via the secondary anchoring device and the connecting member, The steps include connecting the tensioning PC steel member to the jack and installing a reaction frame between the jack and the bearing plate, The process involves using the jack to tension the tensioning PC steel material, thereby tensioning the primary PC steel material via the secondary anchoring device, the connecting member, and the primary anchoring device, and correcting the gap between the bearing plate, which is screwed with the primary sleeve and the fixing member, by changing the screwed state between the bearing plate and the fixing member, which corresponds to the amount the primary PC steel material is pulled into the concrete structure due to a decrease in the adhesive force at the end of the primary PC steel material when the primary PC steel material is protruding. The steps include removing the tensioning PC steel material, the secondary anchoring device, the connecting member, the jack, and the reaction frame, The steps include connecting the secondary PC steel material to the primary anchoring device via the secondary anchoring device and the connecting member, The steps include attaching the fixing member, the primary fixing member, the connecting member, and the coupler sheath covering the secondary fixing member to the bearing plate, The steps include: pouring concrete including the coupler sheath and the secondary PC steel material to form a new concrete structure; A method for connecting PC steel members, characterized by including the step of tensioning the secondary PC steel members after the poured concrete has hardened.

8. A method for widening a bridge, comprising adding a new girder along an existing girder made of concrete, connecting a new PC steel member to be placed in the new girder to an existing lateral PC steel member that is placed in the existing girder and has adhesive force acting on its circumferential surface, thereby integrating the new girder with the existing girder, using a connector described in any one of claims 1 to 3, and introducing tensile force to integrate the new girder with the existing girder, The steps include: dismantling a portion of the existing girder, removing the primary anchoring device provided at the end of the existing PC steel material that connects to the newly installed PC steel material, and causing the primary PC steel material to protrude from the existing girder; The steps include inserting the protruding primary PC steel member into the insertion hole of the fixing member and attaching the bearing plate, to which the fixing member is screwed, to the end face of the structure, The steps include: arranging the primary side anchoring device, which includes the sleeve and the wedge, on the protruding primary side PC steel material; The steps include connecting the tensioning PC steel material, which replaces the secondary PC steel material, to the primary anchoring device via the secondary anchoring device and the connecting member, The steps include connecting the tensioning PC steel member to the jack and installing a reaction frame between the jack and the bearing plate, The process involves using the jack to tension the tensioning PC steel material, thereby tensioning the primary PC steel material via the secondary anchoring device, the connecting member, and the primary anchoring device, and correcting the gap between the bearing plate, which is screwed with the primary sleeve and the fixing member, by changing the screwed state between the bearing plate and the fixing member, which corresponds to the amount the primary PC steel material is pulled into the concrete structure due to a decrease in the adhesive force at the end of the primary PC steel material when the primary PC steel material is protruding. The steps include removing the tensioning PC steel material, the secondary anchoring device, the connecting member, the jack, and the reaction frame, The steps include connecting the secondary PC steel material to the primary anchoring device via the secondary anchoring device and the connecting member, The steps include attaching the fixing member, the primary fixing member, the connecting member, and the coupler sheath covering the secondary fixing member to the bearing plate, Including the aforementioned coupler sheath and the secondary PC steel material, the area forming the newly constructed girder The steps include: pouring concrete between the area or a newly constructed girder that has been formed in advance and the existing girder to form a girder connecting concrete structure as a new concrete structure; A method for widening a bridge, characterized by including the step of tensioning the secondary PC steel members after the poured concrete has hardened.

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