How to replace precast PC deck slabs

Abstract

To provide a replacement method for precast PC floor slabs, which enables replacing just a PC floor slab that needs to be replaced with a new PC floor slab.SOLUTION: A replacement method for precast PC floor slabs comprises: a shaving-off step of shaving off an existing PC floor slab 80 to expose a third anchoring device 25 and a fourth anchoring device 35, which are embedded in the existing PC floor slab and preinstalled on an existing tendon 82 of the existing PC floor slab; a holding step of mounting a holding device 51 onto the third anchoring device 25 and the fourth anchoring device 35 to hold tensile force of the existing tendon 82; a cutting step of cutting the existing tendon 82 between the third anchoring device 25 and the fourth anchoring device 35 to remove the existing PC floor slab 80 from between the third anchoring device 25 and the fourth anchoring device 35; a connecting step of placing a first floor slab 10 being a precast floor slab in a place from which the existing PC floor slab 80 was removed, and connecting a first tendon 12 through which the first floor slab 10 penetrates, with the third anchoring device 25 and the fourth anchoring device 35; and a tensioning step of tensioning the first tendon 12.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] This invention is a method for replacing precast PC decks. By law Regarding. [Background technology]

[0002] In recent years, in renewal works for expressways, etc., existing bridge decks are being renewed with precast decks made of reinforced concrete manufactured in advance at factories, etc., because this method can significantly shorten the period of road closures. In addition, precast PC decks, in which prestress is introduced in advance using tendons such as PC steel and continuous fiber reinforcement, are becoming common, because they can improve durability and reduce the dead load by reducing the deck thickness.

[0003] As shown in FIG. 22, in the conventional PC deck 90, fixing devices 95 are provided at both ends of the tendons 92 that penetrate a plurality of concrete skeletons 91 to fix the tendons 92 to the skeletons 91. In addition, the skeletons 91 on which the fixing devices 95 are provided are also provided with fixing devices 98 for other tendons 97 different from the tendons 92 on which the fixing devices 95 are provided. For this reason, when replacing a damaged existing PC deck 90, it is necessary to replace not only the damaged portion but also the entire area between the fixing devices 95, 95. And, when removing the fixing device 95, it is necessary to remove the skeletons 91 on which the fixing devices 95 and 98 are provided. For this reason, healthy PC decks that do not need to be replaced are also removed. Therefore, in the conventional PC deck joining method, there was a situation where only the PC decks that need to be replaced could not be replaced with a new PC deck.

[0004] Conventionally, Patent Document 1 discloses a technique for re-anchoring PC steel members in a narrow working space such as under a girder during bridge repair work for existing PC structures, without providing an intermediate anchoring section.

[0005] The re-anchoring method of Patent Document 1 includes an exposure step in which, in an existing PC structure in which compressive force is applied to the main body portion by PC steel members consisting of multiple tensioned steel wires, the concrete near the position where the PC steel members will be cut is chipped away and the existing attachment portion is removed to expose a pre-calculated length of PC steel members, an installation step in which a support plate base and a support plate supported by the support plate are installed on the end face of the exposed PC steel members to expand the spacing between the multiple steel wires, and a tensioning and fixing step in which a single jack is installed in the space formed by the installation step to tension and fix each PC steel member one by one.

[0006] However, the technology disclosed in Patent Document 1 is only for re-anchoring existing PC steel members, and is not for replacing existing PC decks with new PC decks. For this reason, there is a strong demand for technology that can replace only the PC decks that need to be replaced with new PC decks. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] JP 2015-140555 A Summary of the Invention [Problem to be solved by the invention]

[0008] The present invention has been devised in view of the above-mentioned circumstances, and its object is to provide a method for replacing a precast PC deck that enables only the PC deck that needs to be replaced to be replaced with a new PC deck. Law The purpose is to provide. [Means for solving the problem]

[0009] The precast PC deck replacement method of the present invention is a precast PC deck replacement method for replacing an existing PC deck with a new precast PC deck, and includes a removal step of removing the existing PC deck installed between a second deck and a third deck; a connection step of installing a first deck, which is a precast deck, at the location from which the existing PC deck was removed and connecting a first tendon that has penetrated the first deck to a third fixing device installed on a second tendon that has penetrated the second deck and a fourth fixing device installed on a third tendon that has penetrated the third deck; and a tensioning step of tensioning the first tendon, wherein in the connection step, the first tendon is connected to the third fixing device that is exposed from a side surface of the second deck while being partially embedded in the second deck, and the fourth fixing device that is exposed from a side surface of the third deck while being partially embedded in the third deck. the removal step includes a step of chipping the existing PC deck slab, exposing the third fastener, which is provided on an existing tendon that penetrates continuously through the existing PC deck slab, the second deck slab, and the third deck slab and is embedded in the second deck slab in advance, from a side surface of the second deck slab in a state where the third fastener is partially embedded in the second deck slab, and chipping the existing PC deck slab, exposing the fourth fastener, which is provided on the existing tendon and is embedded in the third deck slab in advance, from a side surface of the third deck slab in a state where the fourth fastener is partially embedded in the third deck slab; and a step of providing a first retaining device to the third fastener, retaining the tension of the existing tendon that penetrates through the second deck slab, and retaining the tension by the first retaining device. the existing tension member that has been held by the second retaining device as the second tension member that is fixed to the second deck via the third fixing device, a second retaining device is provided on the fourth fixing device, and the tension of the existing tension member embedded in the third deck is maintained, so that the existing tension member that has been held by the second retaining device is the third tension member that is fixed to the third deck via the fourth fixing device; and a cutting process of cutting the existing tension member between the third fixing device and the fourth fixing device and removing the existing PC deck, wherein in the removal process, the tension is maintained by the first retaining device and the second retaining device, and then the first retaining device and the second retaining device are removed. It is characterized by: Effect of the Invention

[0011] According to the present invention, it is possible to replace only the PC deck slab that needs to be replaced with a new PC deck slab. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a cross-sectional view showing a first floor slab used in a precast PC floor slab replacement method according to the first embodiment. [Diagram 2] FIG. 2 shows a flowchart of the joining method for precast PC floor slabs according to the first embodiment. [Diagram 3] FIG. 3(a) is a cross-sectional view showing the existing PC deck before the removal process, and FIG. 3(b) is a cross-sectional view showing the existing PC deck after being chipped in the chipping process. [Figure 4] Figure 4(a) is a cross-sectional view showing the state in which the sleeve and wedge are installed during the retaining process, and Figure 4(b) is a cross-sectional view showing the state in which the tension of the existing tendon is retained by the retaining device during the retaining process. [Diagram 5]FIG. 5(a) is a cross-sectional view showing a state in which the holding device has been removed in the holding step, and FIG. 5(b) is a cross-sectional view showing a state in which the existing tendon has been cut in the cutting step. [Figure 6] Figure 6(a) is a cross-sectional view showing the state in which the first deck slab is installed between the second and third deck slabs in the first deck slab installation process, and Figure 6(b) is a cross-sectional view showing the state in which the first connector is connected to the third fixing device and the second connector is connected to the fourth fixing device in the first deck slab connection process. [Figure 7] Figure 7(a) is a cross-sectional view showing the state in which an outer sleeve and a connecting outer sleeve are installed on the first tendon in the first deck installation process, and Figure 7(b) is a cross-sectional view showing the state in which a sleeve and a wedge are installed on one end of the first tendon in the first deck connection process. [Figure 8] Figure 8(a) is a cross-sectional view showing the state in which a pressure plate is installed on one end of the first tension member in the first deck installation process, and Figure 8(b) is a cross-sectional view showing the state in which one end of the first tension member is connected to the third fixing device in the second deck connection process. [Figure 9] Figure 9(a) is a cross-sectional view showing the state in which a screw bushing and a tensioning sleeve are installed on the second fixing device during the tensioning process, and Figure 9(b) is a cross-sectional view showing the state in which a U-shaped chair and a curved chair are installed during the tensioning process. [Figure 10] Figure 10(a) is a cross-sectional view showing the state in which the PC steel strand for pulling the straight chair is tensioned by a tensioning tool during the tensioning process, and Figure 10(b) is a cross-sectional view showing the state in which the first tensioning member is tensioned using a tensioning device during the tensioning process. [Figure 11] Figure 11(a) is a cross-sectional view showing the first deck after tensioning of the first tensioning member has been completed in the tensioning process, and Figure 11(b) is a diagram explaining the precast deck installation process and the grout material filling process. [Figure 12] FIG. 12 is a cross-sectional view showing a first floor slab used in the precast PC floor slab replacement method according to the second embodiment. [Figure 13] FIG. 13 shows a flowchart of a precast PC floor slab replacement method according to the second embodiment. [Figure 14] Figure 14(a) is a cross-sectional view showing the first deck slab after the first deck slab installation process has been completed, and Figure 14(b) is a cross-sectional view showing the state after the second connecting device has been installed on the second fixing device and the fourth fixing device in the third deck slab connection process. [Figure 15] Figure 15(a) is a cross-sectional view showing the state in which the second fixing device and the fourth fixing device are connected by the second connecting device in the third deck slab connecting process, and Figure 15(b) is a cross-sectional view showing the state in which the first tensioning member is tensioned in the tensioning process. [Figure 16] FIG. 16 is a cross-sectional view showing a first floor slab used in the precast PC floor slab replacement method according to the third embodiment. [Figure 17] FIG. 17 shows a flowchart of a method for replacing a precast PC floor slab according to the third embodiment. [Figure 18] Figure 18(a) is a cross-sectional view showing the state in which the first deck slab is installed between the second and third deck slabs in the first deck slab installation process, and Figure 18(b) is a cross-sectional view showing the state in which the first connector is connected to the third fixing device and the second connector is connected to the fourth fixing device in the first deck slab connection process. [Figure 19] Figure 19(a) is a cross-sectional view showing a state in which an outer sleeve is installed on one first tendon and a connecting outer sleeve is installed on the other first tendon in the first deck installation process, and Figure 19(b) is a cross-sectional view showing a state in which a sleeve and a wedge are installed on the first tendon in the first deck connection process. [Figure 20] Figure 20(a) is a cross-sectional view showing the state in which a pressure plate is installed on the first tendon in the first deck installation process, and Figure 20(b) is a cross-sectional view showing the state in which the first tendon is connected to the third fixing device in the second deck connection process, and the state in which the first tendon is connected to the fourth fixing device in the third deck connection process. [Figure 21] FIG. 21(a) is a cross-sectional view showing a state in which the first tendon is tensioned in the tensioning process, and FIG. 21(b) is a cross-sectional view showing the first deck after the tensioning process is completed. [Figure 22] FIG. 22 is a cross-sectional view showing a conventional PC deck slab. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] Hereinafter, a method for replacing a precast PC deck and a method for joining a precast PC deck according to an embodiment will be described in detail with reference to the drawings. In each drawing, the vertical direction is the vertical direction Z, one planar direction that intersects with the vertical direction Z, for example, perpendicular to it, is the extension direction X, and another planar direction that intersects with the vertical direction Z and the extension direction X, for example, perpendicular to it, is the width direction Y. One side of the extension direction X is the first extension direction X1, and the other side is the second extension direction X2. In each drawing, common parts are given common reference symbols, and duplicated explanations are omitted.

[0014] <First embodiment: Method for replacing precast PC floor slab> First, a first floor slab 10 used in the precast PC floor slab replacement method according to the first embodiment will be described.

[0015] As shown in FIG. 1, the first deck 10 is a precast PC deck. The first deck 10 is provided between the second deck 20 and the third deck 30, which are existing PC decks. The first deck 10 has a T-shaped cross section along the extension direction X and a first tendon 12 for applying prestress. The first deck 10 has a main body 11 through which the first tendon 12 passes, and extensions 18 and 19 which are the remaining portions obtained by cutting out both sides of the main body 11 in the extension direction X. The main body 11 is separated from the second deck 20 and the third deck 30.

[0016] The extension portion 18 is formed on the second deck 20 side of the upper end of the main body 11. A precast plate 71 is installed on the first deck 10 on the opposite side of the extension portion 18, with one end 13 of the first tendon 12 in between. The precast plate 71 is a plate material extending from the end face of the main body 11 in the first extension direction X1 to the second deck 20, and is installed at the lower end of the main body 11. A lateral tightening member 73 extending in the width direction Y is arranged inside the precast plate 71.

[0017] The extension portion 19 is formed on the third deck 30 side of the upper end of the main body 11. A precast plate 72 is installed on the first deck 10 on the opposite side of the extension portion 19, with the other end 14 of the first tendon 12 in between. The precast plate 72 is a plate material extending from the end face of the main body 11 in the second extension direction X2 to the third deck 30, and is installed at the lower end of the main body 11. A lateral tightening member 74 extending in the width direction Y is arranged inside the precast plate 72.

[0018] The first tendon 12 is made of, for example, a PC steel strand and extends linearly in the extension direction X. A sheath tube 17 is provided around the first tendon 12, and the sheath tube 17 is filled with grout material. Note that the first tendon 12 can also use a continuous fiber reinforcing material such as carbon fiber or resin fiber as the tendon.

[0019] The first tendon 12 has one end 13 which is an end on the first extension direction X1 side and the other end 14 which is an end on the second extension direction X2 side. The one end 13 of the first tendon 12 and the other end 14 of the first tendon 12 protrude from the main body 11 of the first deck 10.

[0020] A first fixing tool 150 is fixed to one end 13 of the first tendon 12. The first fixing tool 150 has a sleeve 151, a wedge 152, and a pressing plate 153.

[0021] The sleeve 151 is provided around one end 13 of the first tendon 12 and is formed in a cylindrical shape. The inner surface of the sleeve 151 is formed as an inclined surface, and a wedge 152 is provided on the inside. The wedge 152 is disposed inside the sleeve 151 and has a wedge-shaped outer shape. The pressing plate 153 is provided on the end face of the wedge 152.

[0022] One end 13 of the first tendon 12 is connected to the second tendon 22 by a first connector 155. The first connector 155 connects the first fixing device 150 to a third fixing device 25, which will be described later. The first connector 155 has a connection plug 156 connected to the third fixing device 25, and a mantle sleeve 157 connected to the connection plug 156 and formed into a cylindrical shape.

[0023] A second fixing tool 160 is fixed to the other end 14 of the first tendon 12. The second fixing tool 160 has a sleeve 161, a wedge 162, and a fixing member 163.

[0024] The sleeve 161 is provided around the first tendon 12 and is formed in a cylindrical shape. The inner surface of the sleeve 161 is formed with an inclined surface, and a wedge 162 is provided on the inside. The wedge 162 is disposed inside the sleeve 161 and has a wedge-shaped outer shape. The fixing member 163 is, for example, a ring nut, and is provided around the sleeve 161. The second fixing device 160 is fixed to the first tendon 12 by rotating the fixing member 163 using a tensioning device.

[0025] The other end 14 of the first tendon 12 is connected to the third tendon 32 by a second connector 165. The second connector 165 connects the second fixing device 160 to a fourth fixing device 35, which will be described later. The second connector 165 has a connection plug 166 connected to the fourth fixing device 35, and a connection outer sleeve 167 connected to the connection plug 166.

[0026] The connecting outer sleeve 167 is formed in a box shape, and has the second fastener 160 provided at one end and the connecting plug 166 provided at the other end.

[0027] The second deck 20 is an existing PC deck and has a second tendon 22 for applying prestress. The second tendon 22 is an existing tendon separate from the first tendon 12, and for example, a PC steel strand is used. The second tendon 22 can also be made of continuous fiber reinforcement such as carbon fiber or resin fiber. A third fixing device 25 is provided at the end of the second tendon 22. The second deck 20 may be a precast deck.

[0028] The third fixing device 25 is embedded in the second deck 20 and fixes the second tendon 22 to the second deck 20. The third fixing device 25 is connected to the first fixing device 150 by the first connector 155. The third fixing device 25 has a sleeve 251, a wedge 252, and a bearing plate 253. Resin mortar 254 is filled around the third fixing device 25.

[0029] The sleeve 251 is provided around the second tendon 22 and is formed in a cylindrical shape. The inner surface of the sleeve 251 is formed as an inclined surface, and a wedge 252 is provided on the inside. The wedge 252 is disposed on the inside of the sleeve 251, and has a wedge-shaped outer shape. The support plate 253 transmits the tension force of the third fixing device 25 to the second deck 20, and the support plate 253 is provided with the sleeve 251 and the wedge 252.

[0030] The third deck 30 is an existing PC deck and has a third tendon 32 for applying prestress. The third tendon 32 is an existing tendon separate from the first tendon 12, and for example, a PC steel strand is used. The third tendon 32 can also be made of continuous fiber reinforcement such as carbon fiber or resin fiber. A fourth anchor 35 is provided at the end of the third tendon 32. The third deck 30 may be a precast deck.

[0031] The fourth fixing device 35 is embedded in the third deck 30 and fixes the third tendon 32 to the third deck 30. The fourth fixing device 35 is connected to the second fixing device 160 by the second connector 165. The fourth fixing device 35 has a sleeve 351, a wedge 352, and a bearing plate 353. Resin mortar 354 is filled around the fourth fixing device 35.

[0032] The sleeve 351 is provided around the third tendon 32 and is formed in a cylindrical shape. The inner surface of the sleeve 351 is formed as an inclined surface, and a wedge 352 is provided on the inside. The wedge 352 to which the connection plug 166 is connected is disposed on the inside of the sleeve 351, and has a wedge-shaped outer shape. The support plate 353 transmits the tension of the fourth fixing device 35 to the third deck 30, and the support plate 353 is provided with the sleeve 351 and the wedge 352.

[0033] <How to replace precast PC floor slab S600> Next, the precast PC floor slab joining method S100 according to the first embodiment will be described together with the PC floor slab replacement method S600 according to the first embodiment. The PC floor slab replacement method S600 replaces the existing PC floor slab 80 with a new PC floor slab, the first floor slab 10. The precast PC floor slab joining method S100 joins the first floor slab 10, which is a precast floor slab, by applying prestress.

[0034] As shown in FIG. 2, the PC deck replacement method S600 includes a removal step S610 and a precast PC deck joining method S100.

[0035] As shown in Fig. 3(a), the existing PC deck 80 is a PC deck and has existing tendons 82 for applying prestress. The existing PC deck 80 is installed between the second deck 20 and the third deck 30, which are existing PC decks. The existing tendons 82 penetrate the second deck 20, the third deck 30, and the existing PC deck 80. In addition, the third fixing device 25 is embedded in advance in the second deck 20, and the fourth fixing device 35 is embedded in advance in the third deck 30.

[0036] <Removal process S610> In the removal process S610, the existing PC deck 80 installed between the second deck 20 and the third deck 30 is removed. The removal process S610 includes a chipping process S620, a holding process S630, and a cutting process S640.

[0037] <Scamping process S620> As shown in FIG. 3(b), in the chipping step S620, the existing PC deck 80 is chipped, and the third fastener 25, which is provided on the existing tension member 82 penetrating the existing PC deck 80, the second deck 20, and the third deck 30 and is embedded in the second deck beforehand, is exposed from the side of the second deck 20 in a state where it is partially embedded in the second deck 20. Also, in the chipping step S620, the existing PC deck 80 is chipped, and the fourth fastener 35, which is provided on the existing tension member 82 and is embedded in the third deck 30 beforehand, is exposed from the side of the third deck 30 in a state where it is partially embedded in the third deck 30. At this time, the existing tension member 82 is also exposed. When chipping the existing PC deck 80, a chipping means such as a water jet is used.

[0038] Then, in the chipping process S620, the support plate 253 is left on the second deck 20, and the sleeve 251 is slid along the existing tendons 82 to be removed from the support plate 253. Also, the wedge 252 and the adjustment ring 255 provided on the sleeve 251 are removed. Similarly, in the chipping process S620, the support plate 353 is left on the third deck 30, and the sleeve 351 is slid along the existing tendons 82 to be removed from the support plate 353. Also, the wedge 352 and the adjustment ring 355 provided on the sleeve 351 are removed. The adjustment rings 255, 355 are for adjusting the positions of the sleeve 251, 351, and are formed in a cylindrical shape. When removing the adjustment rings 255, 355, they can be cut with a cutter or the like.

[0039] <Holding process S630> 4(a), in the holding step S630, the slid sleeve 251 is provided on the support plate 253, and a new wedge 252 is provided on the sleeve 251. Similarly, in the holding step S630, the slid sleeve 351 is provided on the support plate 353, and a new wedge 352 is provided on the sleeve 351.

[0040] In the holding step S630, as shown in Fig. 4(b), a holding device 51 is installed on the exposed third fastener 25. Similarly, in the holding step S630, a holding device 51 is installed on the exposed fourth fastener 35. As the holding device 51, for example, a catamaran jack is used.

[0041] In the retention step S630, the retention device 51 is used to retain the tension of the existing tendon 82 penetrating the second deck 20, causing it to function as the second tendon 22. Also, in the retention step 630, the retention device 51 is used to retain the tension of the existing tendon 82 penetrating the third deck 30, causing it to function as the third tendon.

[0042] In the retaining process S630, the tension of the existing tendon 82 penetrating the second deck 20 is retained. As a result, the existing tendon 82 penetrating the second deck 20 functions as the second tendon 22. Similarly, in the retaining process S630, the tension of the existing tendon 82 penetrating the third deck 30 is retained. As a result, the existing tendon 82 penetrating the third deck 30 functions as the third tendon 32. Thereafter, as shown in FIG. 5(a), the retaining device 51 is removed.

[0043] <Cutting process S640> 5(b), in the cutting process S640, the existing tendon 82 between the third fixing tool 25 and the fourth fixing tool 35 is cut, and the existing PC deck 80 is removed. Then, in the removal process S610, resin mortar 254 is filled around the third fixing tool 25, and resin mortar 354 is filled around the fourth fixing tool 35, as necessary.

[0044] Next, the precast PC deck joining method S100 is performed.

[0045] As shown in Figure 2, the method S100 for joining precast PC deck slabs includes a connection process S110 for connecting one end 13 of a first tension member 12 passing through a first deck 10, which is a precast deck, to a second tension member 22 passing through a second deck 20, and for connecting the other end 14 of the first tension member 12 of the first deck 10 to a third tension member 32 passing through a third deck 30 arranged on the opposite side of the second deck 20 across the first deck 10, and a tensioning process S150 for tensioning the first tension member 12.

[0046] <Connection step S110> The connection process S110 includes a first deck installation process S120 in which the first deck 10 is installed between the second deck 20 and the third deck 30, a second deck connection process S130 in which one end 13 of the first tension member 12 and the second tension member 22 of the second deck 20 are connected using a first connector 155, and a third deck connection process S140 in which the other end 14 of the first tension member 12 and the third tension member 32 of the third deck 30 are connected using a second connector 165.

[0047] <1st floor slab installation process S120> As shown in FIG. 6(a), in the first deck installation step S120, the first deck 10 is lowered by a crane or the like and installed at the location where the existing PC deck 80 has been removed.

[0048] 6(b), in the first floor slab installation process S120, the sleeve 251 of the third fixing device 25 embedded in the second floor slab 20 is filled with resin mortar 158, and the connection plug 156 of the first connector 155 is connected to the third fixing device 25. Similarly, in the first floor slab installation process S120, the sleeve 351 of the fourth fixing device 35 embedded in the third floor slab 30 is filled with resin mortar 168, and the connection plug 166 of the second connector 165 is connected to the fourth fixing device 35.

[0049] 7(a), in the first deck slab installation process S120, a jacket sleeve 157 is installed on one end 13 of the first tendon 12 that penetrates the main body 11 of the first deck slab 10. Also in the first deck slab installation process S120, a connection jacket sleeve 167 is inserted into the other end 14 of the first tendon 12, and is connected to the fourth fixing device 35 using a connection plug 166.

[0050] Then, as shown in Fig. 7(b), in the first deck installation process S120, a sleeve 151 and a wedge 152 are provided on the outer sleeve 157, thereby installing the first fixing device 150 on one end 13 of the first tendon 12. Then, as shown in Fig. 8(a), the sleeve 151 and the wedge 152 are pushed out from the outer sleeve 157, and a pressing plate 153 is provided on the sleeve 151.

[0051] <Second floor slab connection process S130> Next, as shown in FIG. 8(b), the outer sleeve 157 is connected to the connection plug 156, thereby connecting the first fixing device 150 and the third fixing device 25 together.

[0052] <Third floor slab connection process S140> Next, in the third deck slab connecting process S140, the second fixing device 160 is installed on the other end 14 of the first tendon 12 by providing a sleeve 161, a wedge 162, and an fixing member 163 on a connecting outer sleeve 167.

[0053] <Tension process S150> Next, a tensioning process S150 is performed in which the linearly extended first tension member 12 is tensioned from a direction inclined to the extension direction of the first tension member 12 by a tensioning device 76 provided between the other end 14 of the first tension member 12 and the fourth fixing device 35.

[0054] In the tensioning process S150, a tensioning connector 78 is installed in the second fixing device 160. The tensioning connector 78 has a threaded bushing 781, a tensioning sleeve 782, a U-shaped chair 783, a curved chair 784, a straight chair 785, a fixing bolt 786, a pulling grip 787, a pulling strand 789, and a tensioning PC steel strand 788.

[0055] 9(a), in the tensioning process S150, a screw bushing 781 is inserted into the connection outer sleeve 167, and the inserted screw bushing 781 is connected to the sleeve 161. Then, in the tensioning process S150, a tensioning sleeve 782 is inserted into the connection outer sleeve 167, and the inserted tensioning sleeve 782 is connected to the screw bushing 781. In the tensioning process S150, a hole is provided in the tensioning sleeve 782 through which the other end 14 of the first tension member 12 is inserted, and the screw bushing 781 is screwed into a screw provided on the outer periphery of the sleeve 161 to fix it.

[0056] 9(b), in the tensioning process S150, a tensioning PC steel strand 788 is attached to a tensioning sleeve 782. A U-shaped chair 783 is installed in the tensioning sleeve 782, and a curved chair 784 is installed in the U-shaped chair 783.

[0057] In the tensioning process S150, the second fixing tool 160, the screw bushing 781, and the tensioning sleeve 782 are arranged inside the U-shaped chair 783 which is formed in a U-shape in a plan view. The curved chair 784 is for tensioning the first tension member 12 in a direction inclined at a predetermined angle, and is connected to the U-shaped chair 783 by a fixing bolt 786. This makes it possible to prevent the curved chair 784 from shifting relative to the U-shaped chair 783. Then, in the tensioning process S150, the pulling grip 787 is connected to the curved chair 784, and the pulling strand 789 is attached.

[0058] Then, as shown in FIG. 10(a), in the tensioning step S150, a straight chair 785 is inserted into a tensioning PC steel strand 788.

[0059] Next, in the tensioning process S150, a tensioning tool 75 is installed on the opposite side of the U-shaped chair 783 with the straight chair 785 in between, and the tensioning tool 75 is used to tension the pulling strand 789, pulling the straight chair 785 to the curved chair 784, and integrating the straight chair 785 and the curved chair 784. Then, the straight chair 785 and the curved chair 784 are fastened together by a fixing bolt 786. Thereafter, the tensioning tool 75 is removed from the straight chair 785.

[0060] Next, as shown in Fig. 10(b), in the tensioning step S150, the first tension member 12 is tensioned using a tensioning device 76. The tensioning device 76 has a tensioning jack 761 and a pulling head 762. The tensioning jack 761 is connected to a straight chair 785. The pulling head 762 is installed on the opposite side of the straight chair 785 with the tensioning jack 761 in between.

[0061] In the tensioning step S150, the first tendon 12 is tensioned in a direction inclined to its extension direction by using a tensioning device 76 installed on the opposite side of the U-shaped chair 783 across the straight chair 785. This allows the linearly extended first tendon 12 to be tensioned in a direction inclined to the extension direction of the first tendon 12.

[0062] In the tensioning step S150, the fixing member 163 is rotated when tensioning the first tendon 12, thereby fixing the second fixing device 160 to the first tendon 12. By tensioning the first tendon 12, as shown in FIG. 11(a), the first tendon 12 stretches, the wedge 162 bites into the sleeve 161, and the connecting outer sleeve 167 stretches, so that a gap L is generated between the sleeve 161 and the connecting outer sleeve 167, and the second fixing device 160 is fixed to the first tendon 12.

[0063] As shown in FIG. 11(b), the precast PC deck joining method S100 may further include a precast plate installation step S160 and a grout material filling step S170 after the tensioning step S150.

[0064] <Precast plate installation process S160> In the precast plate installation process S160, the first deck 10 has a main body 11 on which the first tendon 12 is arranged and which is separated from the second deck 20 and the third deck 30, and extension portions 18, 19 which are remaining portions obtained by cutting out both sides of the main body 11 in the extension direction X of the first tendon 12.Precast plates 71, 72 are installed on the opposite side of the extension portions 18, 19, sandwiching the end of the first tendon 12 between them.

[0065] <Grout filling process S170> In the grout filling process S170, grout is filled into the inside of the sheath tube 17 arranged around the first tendon 12. The sheath tube 17 is provided with an injection hose connected to an injection port formed on the outer surface of the first deck slab 10. When filling with grout, a nipple is provided at the injection port on the underside of the first deck slab 10, and the grout is filled into the inside of the sheath tube 17 from the injection hose. After filling with grout, the nipple is removed, and the injection port is filled with a filler such as resin mortar, thereby closing the injection port.

[0066] In the present invention, the grout filling step S170 may be performed after the precast plate installing step S160, or the precast plate installing step S160 may be performed after the grout filling step S170.

[0067] This completes the precast PC deck joining method S100.

[0068] According to this embodiment, the removal process S610 includes chipping the existing PC deck 80, exposing the third fastener 25, which is provided on the existing tendon 82 that penetrates the existing PC deck 80, the second deck 20, and the third deck 30 and has been embedded in advance in the second deck 20, from the side of the second deck 20 in a state where it is partially embedded in the second deck 20, and chipping the existing PC deck 80, exposing the fourth fastener 35, which is provided on the existing tendon 82 and has been embedded in advance in the third deck 30, from the side of the second deck 20 in a state where it is partially embedded in the third deck 30. The method includes a chipping process S620 for exposing the existing tension member 82 from the side of the slab 30, a holding process S630 for attaching a retaining device 51 to the third fixing device 25 and holding the tension of the existing tension member 82 that has penetrated the second deck 20 to form it into the second tension member 22, and a holding device 51 for attaching the fourth fixing device 35 and holding the tension of the existing tension member 82 embedded in the third deck 30 to form it into the third tension member 32, and a cutting process S640 for cutting the existing tension member 82 between the third fixing device 25 and the fourth fixing device 35 and removing the existing PC deck slab 80.

[0069] This makes it possible to remove only the existing prestressed PC deck 80. Therefore, it becomes possible to replace the existing PC deck 80 that needs to be replaced with a new first deck 10.

[0070] Furthermore, according to this embodiment, one end 13 of the first tendon 12 is connected to the third fixing device 25, and the other end 14 of the first tendon 12 is connected to the fourth fixing device 35. This allows the first deck 10, which is to be newly installed between the second deck 20 and the third deck 30, to be prestressed and joined. Therefore, instead of joining sequentially in one direction as in conventional prestressed decks, the first tendon 12 can also be tensioned for a deck sandwiched between two existing decks. In this way, construction can be performed from two directions, improving the freedom of construction.

[0071] In addition, according to this embodiment, in the connection step S110, one end 13 of the first tendon 12 is connected to the second tendon 22 of the second deck 20, and the other end 14 of the first tendon 12 is connected to the third tendon 32 of the third deck 30. This allows prestress to be applied to the first deck 10 by the first tendon 12 with both ends connected, and reduces the number of times the first tendon 12 is tensioned. This makes it possible to complete the construction in a short time.

[0072] Furthermore, according to this embodiment, the third fixing device 25 is embedded in the second slab 20, which is an existing PC slab, and the fourth fixing device 35 is embedded in the third slab 30, which is an existing PC slab. This makes it possible to reduce the area of ​​the existing PC slab 80 that is chipped to expose the third fixing device 25 and the fourth fixing device 35. This makes it possible to carry out construction in a short time.

[0073] Furthermore, according to this embodiment, the third fixing device 25 is embedded in the second slab 20, which is an existing PC slab, and the fourth fixing device 35 is embedded in the third slab 30, which is an existing PC slab. This makes it possible to reduce the space required to connect the first tendon 12 to the third fixing device 25 and the fourth fixing device 35. This makes it possible to carry out construction even in narrow spaces.

[0074] According to this embodiment, in the tensioning step S150, the linearly extended first tendon 12 is tensioned from a direction inclined with respect to the extension direction X of the first tendon 12. This makes it possible to tension the first tendon 12 even if the space required to apply tension to the first tendon 12 is narrow. This makes it possible to improve the freedom of construction without being subject to spatial restrictions.

[0075] According to this embodiment, in the tensioning step S150, the first tendon 12 is tensioned by a tensioning device 76 provided between the other end 14 of the first tendon 12 and the end of the third tendon 32. This allows the first tendon 12 to be tensioned while being held in a straight line. Therefore, prestress can be applied to the first deck 10 more efficiently than in the case where the first tendon 12 is curved. Also, the thickness of the first deck 10 can be reduced more than in the case where the first tendon 12 is curved.

[0076] In the above-described embodiment, the first tendon 12 is tensioned by the tensioning device 76 provided between the other end 14 of the first tendon and the end of the third tendon 32, but in the present invention, the joining mode at one end 13 and the joining mode at the other end 14 may be reversed, and the first tendon 12 may be tensioned by the tensioning device 76 provided between one end 13 of the first tendon 12 and the end of the second tendon 22. Even in this case, the above-described action and effect can be exerted.

[0077] Furthermore, according to this embodiment, when removing the existing PC floor slab 80 and replacing it with the new first floor slab 10, there is no need to pour in-situ concrete into the first floor slab 10, the second floor slab 20, and the third floor slab 30. Therefore, the first floor slab 10, the second floor slab 20, and the third floor slab 30 can all be precast floor slabs, making it possible to complete the replacement work in a short period of time.

[0078] According to this embodiment, the method includes a connecting step S110 in which one end 13 of the first tendon 12 penetrating the first slab 10, which is a precast slab, is connected to the third fixing device 25 and the other end 14 of the first tendon 12 of the first slab 10 is connected to the third fixing device 25, and a tensioning step S150 in which the first tendon 12 is tensioned. As a result, the first slab 10 is prestressed by the first tendon 12. In the newly installed first slab 10, the connection between the one end 13 of the first tendon 12 and the third fixing device 25 is released, and the connection between the other end 14 of the first tendon 12 and the third fixing device 25 is released, so that only the prestress of the first slab 10 can be released without chipping the existing first slab 10.

[0079] That is, in the removal process, the third fixing device 25 partially embedded in the second deck 20 and exposed from the side of the second deck 20 is disconnected from one end of the existing tension member (the existing first tension member 12) that penetrates the first deck 10, which is the existing PC deck and was connected to the third fixing device 25, and the fourth fixing device 35 partially embedded in the third deck 30 and exposed from the side of the third deck 30 is disconnected from the other end of the existing tension member (the existing first tension member 12) that was connected to the fourth fixing device 35, and the existing first deck 10 is removed. This allows only the prestress of the existing first deck 10 to be released. Therefore, even if the existing PC deck that needs to be replaced is the first deck 10, it is also possible to replace only the existing first deck 10 with a new first deck 10.

[0080] In addition, when removing the existing first floor slab 10, there is no need to chip the existing first floor slab 10. Therefore, it is possible to remove the existing first floor slab 10 in a shorter time.

[0081] According to this embodiment, the first deck 10 has a main body 11 through which the first tendon 12 penetrates and which is separated from the second deck 20 and the third deck 30, and extensions 18, 19 which are remaining portions obtained by cutting out both sides of the main body 11 in the extension direction X. The first deck 10 further includes a precast plate installation step S160 for installing precast plates 71, 72 on the opposite side of the extensions 18, 19 across both ends 13, 14 of the first tendon 12. As a result, the one end 13 of the first tendon 12 is protected by the extensions 18 and the precast plate 71. In addition, the other end 14 of the first tendon 12 is protected by the extensions 19 and the precast plate 72. This makes it possible to suppress deterioration of the one end 13 and the other end 14 of the first tendon 12 due to corrosion or the like, and improve the durability of the first tendon 12.

[0082] According to this embodiment, a grout filling step S170 is further provided for filling the sheath tube 17 arranged around the first tendon 12 with grout. This makes it possible to stabilize the first tendon 12 inside the sheath tube 17. This makes it possible to maintain the prestress applied by the first tendon 12 for a longer period of time.

[0083] <Second embodiment: Precast PC floor slab replacement method S700> Next, a precast PC floor slab replacement method S700 according to the second embodiment will be described. The PC floor slab replacement method S700 includes a removal step S610 and a precast PC floor slab joining method S200. In this embodiment, a second connector 265 is used.

[0084] 12, the second connector 265 has a first sleeve 266, a second sleeve 267, and a plug 268. The first sleeve 266 is connected to the second fastener 160. The second sleeve 267 is connected to the fourth fastener 35 and is spaced apart from the first sleeve 266. The plug 268 connects the first sleeve 266 and the second sleeve 267. By rotating the plug 268, the distance between the first sleeve 266 and the second sleeve 267 can be adjusted.

[0085] <Second embodiment: Precast PC floor slab replacement method S700> Next, the procedure of the precast PC floor slab replacement method S700 according to the second embodiment will be described. In the precast PC floor slab replacement method S700, first, the removal step S610 is performed. The removal step S610 is omitted because it is the same as the first embodiment.

[0086] As shown in Fig. 13, after the removal step S610, a precast PC floor slab joining method S200 according to the second embodiment is performed. The precast PC floor slab joining method S200 according to this embodiment includes a connection step S210 in which one end 13 of a first tendon 12 penetrating a first floor slab 10, which is a precast floor slab, is connected to a second tendon 22 penetrating a second floor slab 20, and the other end 14 of the first tendon 12 of the first floor slab 10 is connected to a third tendon 32 penetrating a third floor slab 30 arranged on the opposite side of the second floor slab 20 across the first floor slab 10, and a tensioning step S250 in which the first tendon 12 is tensioned.

[0087] <Connection step S210> The connection process S210 includes a first floor slab installation process S120, a second floor slab connection process S130, and a third floor slab connection process S240. The first floor slab installation process S120 and the second floor slab connection process S130 are the same as those in the first embodiment, and therefore will not be described.

[0088] <Third floor slab connection process S240> As shown in Figure 14(a), after completion of the first deck slab installation process S120 and the second deck slab connection process S130, the first fixing device 150 provided at one end 13 of the first tension member 12 is connected to the third fixing device 25 of the second deck slab 20.

[0089] 14(b), in the third floor slab connecting process S240, the second fixing device 160 and the fourth fixing device 35 are connected by the second connector 265. In the third floor slab connecting process S240, a first sleeve 266 is connected to the second fixing device 160, and a second sleeve 267 is connected via a connection plug 166 connected to the fourth fixing device 35.

[0090] 15(a), in the third deck slab connecting step S240, the first sleeve 266 and the second sleeve 267 are connected by the plug 268. In this manner, in the third deck slab connecting step S240, the other end 14 of the first tendon 12 and the fourth fixing device 35 of the third deck slab 30 are connected by the second connecting device 265.

[0091] <Tension process S250> 15(b), a tensioning process S250 is performed in which the first tendon 12 is tensioned by the second connector 165 provided between the other end 14 of the linearly extended first tendon 12 and the end of the third tendon 32. In the tensioning process S250, the plug 268 is rotated to shorten the separation distance between the first sleeve 266 and the second sleeve 267, thereby tensioning the first tendon 12.

[0092] The precast PC deck joining method S200 may further include a precast plate installation step S160 and a grout material filling step S170 after the tensioning step S250.

[0093] According to this embodiment, in the connection step S210, one end 13 of the first tendon 12 is connected to the third fastener 25, and the other end 14 of the first tendon 12 is connected to the fourth fastener 35. This allows the first deck 10, which is to be newly installed between the second deck 20 and the third deck 30, to be prestressed and joined. Therefore, instead of joining sequentially in one direction as in conventional prestressed decks, the tendon 12 can also be tensioned for a deck sandwiched between two existing decks. In this way, construction can be performed from two directions, improving the freedom of construction.

[0094] According to this embodiment, in the connection step S210, one end 13 of the first tendon 12 is connected to the third fixing device 25, and the other end 14 of the first tendon 12 is connected to the fourth fixing device 35. This allows prestress to be applied to the first deck slab 10 by the first tendon 12 with both ends connected, and reduces the number of times the first tendon 12 is tensioned. This makes it possible to complete the construction in a short time.

[0095] According to this embodiment, in the tensioning step S250, the first tendon 12 is tensioned by the second connector 165 provided between the other end 14 of the first tendon 12 and the fourth fixing device 35. At this time, tensioning can be achieved by rotating the plug 268 without applying a reaction force to the tensioning force to the precast PC deck slab itself, making it possible to maintain the tensioning force.

[0096] Furthermore, according to this embodiment, in the tensioning step S250, the first tendon 12 is tensioned by the second connector 165 provided between the other end 14 of the first tendon 12 and the fourth fixing device 35. This allows the first tendon 12 to be tensioned while being held in a straight line. This allows prestress to be applied to the first deck 10 more efficiently than in the case where the first tendon 12 is curved. Also, the thickness of the first deck 10 can be reduced more than in the case where the first tendon 12 is curved.

[0097] Furthermore, according to this embodiment, in the tensioning step S250, the first tendon 12 is tensioned by the second connector 165 provided between the other end 14 of the first tendon 12 and the fourth fixing device 35. This allows the first tendon 12 to be tensioned and released without using a large-scale tensioning device. This allows the tensioning and release of the first tendon 12 to be completed in a shorter time.

[0098] In this embodiment, the first tendon 12 is tensioned by the second connector 165 provided between the other end 14 of the first tendon and the fourth fixing device 35, but in the present invention, the joining mode at one end 13 and the joining mode at the other end 14 may be reversed, and the first tendon 12 may be tensioned by the second connector 165 provided between one end 13 of the first tendon 12 and the third fixing device 25. Even in this case, the above-mentioned action and effect can be exerted.

[0099] According to this embodiment, the method includes a connecting step S110 of connecting one end 13 of a first tendon 12 penetrating a first floor slab 10, which is a precast floor slab, to a second tendon 22 penetrating a second floor slab 20 and connecting the other end 14 of the first tendon 12 of the first floor slab 10 to a third tendon 32 penetrating a third floor slab 30 arranged on the opposite side of the second floor slab 20 across the first floor slab 10, and a tensioning step S150 of tensioning the first tendon 12. As a result, prestress is applied to the first floor slab 10 by the first tendon 12. The newly installed first deck 10 can be released from the prestress only by disconnecting one end 13 of the first tendon 12 from the second tendon 22 of the second deck 20 and disconnecting the other end 14 of the first tendon 12 from the third tendon 32 of the third deck 30, without chipping the existing first deck 10.

[0100] That is, in the removal process, the third fixing device 25 partially embedded in the second deck 20 and exposed from the side of the second deck 20 is disconnected from one end of the existing tension member (the existing first tension member 12) that penetrates the first deck 10, which is the existing PC deck and was connected to the third fixing device 25, and the fourth fixing device 35 partially embedded in the third deck 30 and exposed from the side of the third deck 30 is disconnected from the other end of the existing tension member (the existing first tension member 12) that was connected to the fourth fixing device 35, and the existing first deck 10 is removed. This allows only the prestress of the existing first deck 10 to be released. Therefore, even if the existing PC deck that needs to be replaced is the first deck 10, it is also possible to replace only the existing first deck 10 with a new first deck 10.

[0101] In addition, when removing the existing first floor slab 10, there is no need to chip the existing first floor slab 10. Therefore, it is possible to remove the existing first floor slab 10 in a shorter time.

[0102] <Third embodiment: Precast PC floor slab replacement method S800> Next, a precast PC floor slab replacement method S800 according to the third embodiment will be described. First, a first floor slab 10 used in the precast PC floor slab replacement method S800 according to the third embodiment will be described.

[0103] As shown in Fig. 16, the first deck 10 used in the precast PC deck replacement method S800 according to the third embodiment has one first tendon 12 and the other first tendon 42 for applying prestress. The first deck 10 has a main body 11 through which the one first tendon 12 and the other first tendon 42 pass, and extensions 18, 19 which are the remaining portions obtained by cutting out both sides of the main body 11 in the extension direction X. One end 13 of the one first tendon 12 is connected to the third fixing device 25. The other end 44 of the other first tendon 42 is connected to the fourth fixing device 35.

[0104] The first tendon 12 is inclined with respect to the extension direction X, and one end 13 of the first tendon 12 is disposed higher than the other end 14 of the first tendon 12. The one end 13 of the first tendon 12 and the other end 14 of the first tendon 12 protrude from the main body 11 of the first deck 10.

[0105] A first fixing device 150 is fixed to one end 13 of the first tendon 12. The one end 13 of the first tendon 12 is connected to the second tendon 22 by a first connecting device 155.

[0106] A fifth fixing device 55 is fixed to the other end 14 of the first tendon 12. The fifth fixing device 55 fixes the first tendon 12 to the first deck slab 10. The fifth fixing device 55 has a sleeve 551, a wedge 552, and an fixing member 553.

[0107] The sleeve 551 is provided around the first tendon 12 and is formed in a cylindrical shape. The inner surface of the sleeve 551 is formed as an inclined surface, and a wedge 552 is provided on the inside. The sleeve 551 is provided with an anchoring member 553 on the outer surface. The wedge 552 is placed inside the sleeve 551, and has a wedge-shaped outer shape. The anchoring member 553 uses a ring nut, a shim, or the like, and comes into contact with the first deck slab 10.

[0108] The first tendon 42 is made of, for example, a PC steel strand and is inclined with respect to the extension direction X. One end 43 of the first tendon 42 is disposed lower than the other end 44 of the first tendon 42. A sheath tube 47 is provided around the first tendon 42, and the sheath tube 47 is filled with grout material. Note that the first tendon 42 can also use a continuous fiber reinforcing material such as carbon fiber or resin fiber as the tendon.

[0109] A sixth fixing device 65 is fixed to one end 43 of the first tendon 42. The sixth fixing device 65 fixes the first tendon 42 to the first deck 10. The sixth fixing device 65 has a sleeve 651, a wedge 652, and an fixing member 653.

[0110] The sleeve 651 is provided around the first tendon 42 and is formed in a cylindrical shape. The inner surface of the sleeve 651 is formed as an inclined surface, and a wedge 652 is provided on the inside. The sleeve 651 is provided with an anchoring member 653 on the outer surface. The wedge 652 is placed inside the sleeve 651, and has a wedge-shaped outer shape. The anchoring member 653 uses a ring nut, a shim, or the like, and comes into contact with the first deck slab 10.

[0111] A second fixing device 160 is fixed to the other end 44 of the first tendon 42. The other end 44 of the first tendon 42 is connected to the third tendon 32 by a second connecting device 165.

[0112] Next, a PC floor replacement method S800 according to the third embodiment will be described together with the precast PC floor joining method S500 according to the third embodiment. The PC floor replacement method S800 replaces the existing PC floor 80 with a first floor 10, which is a new PC floor slab.

[0113] As shown in Fig. 17, the PC deck replacement method S800 includes a removal step S610 and a precast PC deck joining method S500. In the precast PC deck replacement method S800, the removal step S610 is first performed. The removal step S610 is omitted because it is the same as the first embodiment.

[0114] Next, the precast PC deck joining method S500 is performed.

[0115] The joining method S500 for precast PC deck slabs includes a connection process S510 in which one end 13 of a first tension member 12 that penetrates a first deck 10, which is a precast deck, is connected to a second tension member 22 that penetrates a second deck 20, and the other end 44 of a first tension member 42 different from the first tension member 12 that penetrates the first deck 10 to a third tension member 32 that penetrates a third deck 30 that is arranged on the opposite side of the second deck 20 across the first deck 10; and a tensioning process S550 in which the first tension member 12 is tensioned from the other end 14 side of the first tension member 12, and the first tension member 42 is tensioned from the one end 43 side of the first tension member 42.

[0116] <Connection step S510> The connecting step S510 includes a first floor slab installation step S520, a second floor slab connecting step S530, and a third floor slab connecting step S540.

[0117] <1st floor slab installation process S520> As shown in FIG. 18(a), in the first floor slab installation process S520, the first floor slab 10 is placed between the second floor slab 20 and the third floor slab 30, which are existing PC floor slabs.

[0118] Next, as shown in FIG. 18(b), in the first deck slab installation process S520, the connection plug 156 is connected to the third fixing fixture 25, and the connection plug 166 is connected to the fourth fixing fixture .

[0119] 19(a), in the first deck slab installation process S520, the first tendon 12 is penetrated through the main body 11 of the first deck slab 10, and a mantle sleeve 157 is installed on one end 13 of the penetrated first tendon 12. Also, in the first deck slab installation process S520, the first tendon 42 is penetrated through the main body 11 of the first deck slab 10, and a connection mantle sleeve 167 is installed on the other end 44 of the penetrated first tendon 42.

[0120] 19(b), in the first deck slab installation process S520, a sleeve 151 and a wedge 152 are provided on the outer sleeve 157, thereby installing the first fixing device 150 to one end 13 of the first tendon 12. Similarly, in the first deck slab installation process S520, a sleeve 161 and a wedge 162 are provided on the connection outer sleeve 167, thereby installing the second fixing device 160 to one end 43 of the first tendon 42.

[0121] 20(a), in the first deck slab installation process S520, the sleeve 151 and the wedge 152 are pushed out from the outer sleeve 157, and the pressing plate 153 is provided on the sleeve 151. Similarly, the sleeve 161 and the wedge 162 are pushed out from the connecting outer sleeve 167, and the pressing plate 164 is provided on the sleeve 161.

[0122] <Second floor slab connection process S530> 20(b), in the second deck connecting step S530, the first fixing device 150 and the third fixing device 25 are connected by connecting the outer sleeve 157 to the connection plug 156. In the second deck connecting step S530, the fifth fixing device 55 is installed on the other end 14 of the first tendon 12.

[0123] <Third floor slab connection process S540> Next, in a third deck slab connecting step S540, the second fixing device 160 and the fourth fixing device 35 are connected by connecting the connection outer sleeve 167 to the connection plug 166. In the third deck slab connecting step S540, a sixth fixing device 65 is installed at one end 43 of the first tendon 42.

[0124] <Tension process S550> 21(a), in the tensioning step S550, a tensioning device 77 is installed in the fifth fixing device 55, and the first tension member 12 is tensioned from the other end 14 side of the first tension member 12 by the tensioning device 77. Also, in the tensioning step S550, a tensioning device 77 is installed in the sixth fixing device 65, and the first tension member 42 is tensioned from the one end 43 side of the first tension member 42 by the tensioning device 77.

[0125] As shown in FIG. 21(b), in the tensioning step S550, after tensioning of the first tendon 12 and the first tendon 42 is completed, the tensioning device 77 is removed.

[0126] Then, in the tensioning step S550, resin mortar 158 is injected into the connection plug 156, and resin mortar 168 is injected into the connection plug 166, as necessary.

[0127] The precast PC deck joining method S100 may further include a precast plate installation step S160 and a grout material filling step S170 after the tensioning step S150.

[0128] The precast PC deck joining method S500 may further include a precast plate installation step S160 and a grout material filling step S170 after the tensioning step S550.

[0129] This completes the PC deck replacement method S800.

[0130] According to this embodiment, there are a chipping process S620 in which the existing PC deck 80 is chipped to expose the third fixing device 25 and the fourth fixing device 35 that are embedded in the second deck 20 and the third deck 30, which are the existing PC decks, and that are also previously provided on the existing tendon 82; a retention process S630 in which a retention device 51 is provided on the third fixing device 25 and the fourth fixing device 35 to retain the tension of the existing tendon 82; and a retention process S640 in which a retention device 51 is provided on the third fixing device 25 and the fourth fixing device 35 to retain the tension of the existing tendon 82. The method includes a cutting process S640 in which the existing tension member 82 is cut and the existing PC deck 80 is removed between the third fixing device 25 and the fourth fixing device 35, a connecting process S510 in which the first deck 10, which is a precast deck, is placed at the location from which the existing PC deck 80 has been removed and the first tension member 12 that has penetrated the first deck 10 is connected to the third fixing device 25 and the fourth fixing device 35, and a tensioning process S550 in which the first tension member 12 is tensioned.

[0131] This makes it possible to remove only the existing prestressed PC deck 80. Therefore, it becomes possible to replace the existing PC deck 80 that needs to be replaced with a new first deck 10.

[0132] Furthermore, according to this embodiment, the first floor slab 10, which is newly installed between the second floor slab 20 and the third floor slab 30, can be prestressed and joined. Therefore, instead of joining sequentially in one direction as in conventional prestressed floor slabs, the first tendon 12 can also be tensioned for the floor slab sandwiched between two existing floor slabs. In this way, construction can be performed from two directions, improving the freedom of construction.

[0133] Furthermore, according to this embodiment, the third fixing device 25 is embedded in the second slab 20, which is an existing PC slab, and the fourth fixing device 35 is embedded in the third slab 30, which is an existing PC slab. This makes it possible to reduce the area of ​​the existing PC slab 80 that is chipped to expose the third fixing device 25 and the fourth fixing device 35. This makes it possible to carry out construction in a short time.

[0134] Furthermore, according to this embodiment, the third fixing device 25 is embedded in the second slab 20, which is an existing PC slab, and the fourth fixing device 35 is embedded in the third slab 30, which is an existing PC slab. This makes it possible to reduce the space required to connect the first tendon 12 to the third fixing device 25 and the fourth fixing device 35. This makes it possible to carry out construction even in narrow spaces.

[0135] According to this embodiment, in the tensioning step S150, the linearly extended first tendon 12 is tensioned from a direction inclined with respect to the extension direction X of the first tendon 12. This makes it possible to tension the first tendon 12 even if the space required to apply tension to the first tendon 12 is narrow. This makes it possible to improve the freedom of construction without being subject to spatial restrictions.

[0136] In particular, according to this embodiment, in the connection step S510, one end 13 of the first tendon 12 is connected to the third fixing device 25, and the other end 44 of the other first tendon 42 different from the first tendon 12 is connected to the fourth fixing device 35, and in the tensioning step S550, the first tendon 12 is tensioned from the other end 14 side of the first tendon 12 connected to the third fixing device 25, and the first tendon 42 is tensioned from the one end 43 side of the first tendon 42 connected to the fourth fixing device 35. This makes it possible to further reduce the area where the existing PC deck 80 is chipped to expose the third fixing device 25 and the fourth fixing device 35. This makes it possible to perform construction in a short time.

[0137] Furthermore, according to this embodiment, the third fixing device 25 is embedded in the second slab 20, which is an existing PC slab, and the fourth fixing device 35 is embedded in the third slab 30, which is an existing PC slab. This makes it possible to reduce the space required to connect the first tendon 12 to the third fixing device 25 and the space required to connect the first tendon 42 to the fourth fixing device 35. This makes it possible to carry out construction even in narrower spaces.

[0138] According to this embodiment, the method includes a connecting step S110 in which one end 13 of one first tendon 12 penetrating the first slab 10, which is a precast slab, is connected to the third fixing device 25 and the other end 14 of the other first tendon 42 is connected to the third fixing device 25, and a tensioning step S150 in which the first tendons 12, 42 are tensioned. As a result, the first slab 10 is prestressed by the first tendons 12, 42. In a newly installed first slab 10, the connection between the one end 13 of one first tendon 12 and the third fixing device 25 is released, and the connection between the other end 44 of the other first tendon 42 and the third fixing device 25 is released, whereby the prestress of only the first slab 10 can be released without chipping the existing first slab 10.

[0139] That is, in the removal process, the third fixing device 25 exposed from the side of the second floor slab 20 in a state where it is partially embedded in the second floor slab 20 and one end of the existing tension member (existing first tension member 12) that penetrates the first floor slab 10, which is an existing PC floor slab, and that was connected to the third fixing device 25, are disconnected, and the fourth fixing device 35 exposed from the side of the third floor slab 30 in a state where it is partially embedded in the third floor slab 30 and the other end of the existing tension member (existing first tension member 42) that was connected to the fourth fixing device 35 are disconnected, and the existing first floor slab 10 is removed. This allows only the prestress of the existing first floor slab 10 to be released. Therefore, even if the existing PC floor slab that needs to be replaced is the first floor slab 10, it is also possible to replace only the existing first floor slab 10 with a new first floor slab 10.

[0140] In addition, when removing the existing first floor slab 10, there is no need to chip the existing first floor slab 10. Therefore, it is possible to remove the existing first floor slab 10 in a shorter time.

[0141] Although some of the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. In addition, these embodiments can be implemented in appropriate combinations. Furthermore, the present invention can be implemented in various new forms in addition to the above-mentioned several embodiments. Therefore, each of the above-mentioned several embodiments can be variously omitted, replaced, and modified without departing from the gist of the present invention. Such new forms and modifications are included in the scope and gist of the present invention, and are included in the scope of the invention described in the claims and the equivalents of the invention described in the claims. [Explanation of symbols]

[0142] 10:1st floor slab 11: Main body 12:1st tendon 13:One end 14:Other end 17: Sheath tube 42: 1st tension material 43:One end 44:Other end 47: Sheath tube 18: Extension part 19: Extension part 150: First fixing device 151: Sleeve 152: Wedge 153: Pressing plate 155: First connector 156: Connection plug 157: Overcoat sleeve 158: Resin mortar 160: Second fixing device 161: Sleeve 162: Wedge 163: Fixing member 164: Presser plate 165: Second connector 166: Connection plug 167: Connection sleeve 168: Resin mortar 265: Second connector 266: 1st sleeve 267: 2nd sleeve 268: Plug 55: 5th fixing device 65: 6th fixing device 20: 2nd floor slab 22:Second tension material 25: Third fixing device 251: Sleeve 252: Wedge 253: Support plate 254: Resin mortar 255: Adjustment ring 30: 3rd floor slab 32:Third tension material 35: 4th fixing device 351: Sleeve 352: Wedge 353: Support plate 354: Resin mortar 51: Holding device 71: Precast plate 73: Horizontal fastening member 72: Precast plate 74: Horizontal fastening member 75: Tension device 76: Tension device 77: Tension device 78: Tensioning connector 80: Existing PC deck 82: Existing tendon 90:PC floor slab 91 :Structure 92: Tensile material 95: Fixture 97: Tensile material 98: Fixture S100: Precast deck joint method S110: Connection process S120: 1st floor slab installation process S130: Second floor slab connection process S140: Third floor slab connection process S150: Tension process S160: Precast plate installation process S170: Grout filling process S200: Precast deck joint method S210: Connection process S240: Third floor slab connection process S250: Tension process S500: Precast deck joint method S510: Connection process S520: 1st floor slab installation process S530: Second floor slab connection process S540: Third floor slab connection process S550: Tension process S600: How to replace precast decks S610: Removal process S620: Scouring process S630: Holding process S640: Cutting process S700: How to replace precast decks S800: How to replace precast decks X: extension direction X1: 1st extension direction X2: Second extension direction Y: width direction Z : Up and down direction

Claims

[Claim 1] A method for replacing an existing PC floor slab with a new precast PC floor slab, comprising: A removal process of removing the existing PC deck installed between the second deck and the third deck; a connection process in which a first deck, which is a precast deck, is installed at the location where the existing PC deck has been removed, and a first tension member penetrating the first deck is connected to a third fastener provided on a second tension member penetrating the second deck, and to a fourth fastener provided on a third tension member penetrating the third deck; and a tensioning step of tensioning the first tendon, In the connecting step, the first tendon is connected to the third fastener that is partially embedded in the second deck and exposed from a side surface of the second deck, and to the fourth fastener that is partially embedded in the third deck and exposed from a side surface of the third deck, The removing step includes: The existing PC deck is chipped, and the third fixing device, which is provided on an existing tension member that penetrates continuously through the existing PC deck, the second deck, and the third deck and is embedded in the second deck in advance, is exposed from a side surface of the second deck while being partially embedded in the second deck; an exposure process in which the existing PC deck is chipped and the fourth fastener provided on the existing tension member and embedded in the third deck in advance is exposed from a side surface of the third deck while being partially embedded in the third deck; a first retaining device is provided on the third fixing device, and the tension of the existing tension member that has penetrated the second deck is maintained, and the existing tension member whose tension is maintained by the first retaining device is fixed to the second deck via the third fixing device as the second tension member; a retaining process of providing a second retaining device to the fourth fixing device, retaining the tension of the existing tension member embedded in the third deck, and making the existing tension member whose tension is retained by the second retaining device into the third tension member fixed to the third deck via the fourth fixing device; A cutting process of cutting the existing tendon between the third fixing device and the fourth fixing device and removing the existing PC deck, In the removing step, tension is maintained by the first holding device and the second holding device, and then the first holding device and the second holding device are removed. A method for replacing a precast PC deck, comprising:

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