Suikan-kyo bridge leakage prevention structure and leakage prevention method

Abstract

To provide a water leakage prevention structure and a water leakage prevention method of a water pipe bridge capable of suppressing malfunction due to breakage of an expansion cover.SOLUTION: In a water leakage prevention structure of a Suikan-kyo Bridge in which a water leakage prevention device 10 for preventing water leakage due to detachment of a pipe body 1 is attached to a pipe joint JT in which end portions of the pipe body 1 forming a pipeline of a bathroom 90 are connected to each other, the water leakage prevention device 10 includes a flexible pipe 14 as a metal expansion cover surrounding the pipe joint JT, and an external fitting member 11,12 joined to both end portions of the flexible pipe 14 in a pipe axis direction and externally fitted to the pipe body 1 in a watertight manner. water pipe bridge, the water leakage preventing device 10 is arranged in an area X sandwiched by a pair of supports 70 in the same abutment 91.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present disclosure relates to a water leakage prevention structure and a water leakage prevention method for preventing water leakage at pipe joints of a water pipe bridge. [Background technology]

[0002] Patent Document 1 describes a water leakage prevention device that is attached to the pipeline of a water pipe bridge. This water leakage prevention device has a pair of outer pipe members that are fitted watertightly onto the outside of the pipe body, and a flexible member that serves as an expandable cover that is provided between the pair of outer fitting members. The expandable cover is arranged to surround a pipe joint that connects the ends of the pipe body. The expandable cover is made of rubber or synthetic resin with reinforcing cords, and is configured to follow the expansion and contraction and inclination of the pipeline.

[0003] The above-mentioned water leakage prevention device can prevent water leakage outside the device even if the pipe body separates from the pipe joint due to an earthquake or other event. However, if a larger extension or displacement occurs and the telescopic cover comes into contact with the bridge abutment or pier, the telescopic cover may be damaged, causing it to malfunction (i.e., it may be unable to maintain water flow). Such malfunctions could have serious consequences for water users, so it is desirable to take measures to prepare for such an unlikely event. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 7-139684 Summary of the Invention [Problem to be solved by the invention]

[0005] The present disclosure has been made in consideration of the above-mentioned circumstances, and its purpose is to provide a water leakage prevention structure and a water leakage prevention method for a water pipe bridge that can suppress malfunctions due to damage to the telescopic cover. [Means for solving the problem]

[0006] The water leakage prevention structure for a water pipe bridge disclosed herein is a water leakage prevention structure for a water pipe bridge in which a water leakage prevention device is attached to a pipe joint connecting the ends of pipes that form the pipeline of the water pipe bridge, to prevent water leakage due to the detachment of the pipes.The water leakage prevention device has a metal expandable cover that surrounds the pipe joint, and external fitting members that are joined to both ends of the expandable cover in the pipe axial direction and are watertightly fitted onto the pipes, and the water leakage prevention device is arranged within an area sandwiched between a pair of supports on the same abutment or the same pier, or within an area sandwiched between a support on the same abutment and a fixed support end of the water pipe bridge.

[0007] The disclosed method for preventing water leakage from an aqueduct bridge comprises attaching a water leakage prevention device to a pipe joint connecting the ends of pipes forming the pipeline of the aqueduct bridge, thereby preventing water leakage due to the detachment of the pipes. The water leakage prevention device has a metal telescopic cover that surrounds the pipe joint, and external fitting members that are joined to both ends of the telescopic cover in the pipe axis direction and are watertightly fitted onto the pipes, and the water leakage prevention device is positioned within an area sandwiched between a pair of supports on the same abutment or the same pier, or within an area sandwiched between a support on the same abutment and a fixed support end of the aqueduct bridge. [Brief explanation of the drawings]

[0008] [Figure 1] Schematic diagram showing the leak prevention structure of the water pipe bridge [Figure 2] FIG. 1 is a diagram showing an installation location of a water leakage prevention device (upper half is a cross-sectional view) in the first embodiment. [Figure 3] Enlarged cross-sectional view showing the area around the pipe fitting [Figure 4] FIG. 10 is a diagram showing a state in which the pipe body is detached from the pipe joint. [Figure 5] FIG. 10 is a diagram showing a state in which the pipe body is detached from the pipe joint. [Figure 6] FIG. 4 is a cross-sectional view showing the periphery of the outer fitting member of FIG. [Figure 7] FIG. 10 is a diagram showing a modified example of the separation prevention mechanism. [Figure 8] A diagram showing the process of installing a water leakage prevention device [Figure 9] A diagram showing the process of installing a water leakage prevention device [Figure 10] A diagram showing the process of installing a water leakage prevention device [Figure 11] FIG. 10 is a diagram showing the installation location of the water leakage prevention device (upper half is a cross-sectional view) in the second embodiment. [Figure 12] FIG. 10 is a diagram showing a modified example of the separation prevention mechanism. [Figure 13] FIG. 10 is a diagram showing a modified example of the separation prevention mechanism. [Figure 14] FIG. 10 is a diagram showing a modified example of the separation prevention mechanism. [Figure 15] FIG. 10 is a diagram showing a modified example of the separation prevention mechanism. DETAILED DESCRIPTION OF THE INVENTION

[0009] An embodiment of the water leakage prevention structure and water leakage prevention method for an aqueduct bridge of the present disclosure will be described.

[0010] [First embodiment] First, a first embodiment will be described with reference to Figures 1 to 10. Figure 1 is a schematic diagram showing a water leakage prevention structure for a water pipe bridge. The water leakage prevention structure is configured by attaching a water leakage prevention device 10 to a pipe joint JT that connects the ends of pipes 1 that form the pipeline of a water pipe bridge 90, to prevent water leakage due to separation of the pipes 1. In Figure 1, the water leakage prevention device 10 is simply depicted by a dashed line. The pipe 1 is, for example, a steel water pipe with a nominal diameter of 900, but specifications such as pipe dimensions can be changed as appropriate depending on the conditions of use, etc.

[0011] The aquatic pipe bridge 90 is a bridge for fluid pipes (water pipes) that is installed to cross rivers, roads, railways, etc. The aquatic pipe bridge 90 is spanned between a pair of abutments 91. Piers 92 are installed midway along the pipes of the aquatic pipe bridge 90, but a pierless structure is also possible. The aquatic pipe bridge 90 has fixed support ends 90E that are fixedly supported by the abutments 91. In this embodiment, both ends of the aquatic pipe bridge 90 are embedded in the concrete that forms the abutment 91, and each end serves as a fixed support end 90E. Bearings 70 that support the vertical load of the aquatic pipe bridge 90 are installed on the abutments 91 and piers 92. The bearings 70 are fixed to the abutments 91 and piers 92 via anchor bolts.

[0012] 2 and 3, the water leakage prevention device 10 includes a flexible pipe 14 as a metal expansion and contraction cover surrounding the pipe joint JT, and outer fitting members 11 and 12 joined to both axial ends of the flexible pipe 14 and watertightly fitted around the pipe body 1. This device 10 forms an enclosed space around the pipe joint JT, preventing water leakage to the outside of the device even if the pipe body 1 becomes detached due to expansion and contraction of the pipe due to temperature changes or vibration or displacement due to an earthquake or the like, or if the sealing material 42, described below, deteriorates. In this embodiment, the water leakage prevention device 10 is disposed in an area X sandwiched between a pair of supports 70 on the same abutment 91. Therefore, the outer fitting members 11 and 12 are both fitted around the outer periphery of the pipe body 1 within the area X.

[0013] The bearing 70 supports the pipe body 1 via a ring support 71. The ring support 71 surrounds the pipe body 1 in the pipe circumferential direction and is fixed to the outer surface of the pipe body 1 by welding or the like. The region X may be an region inside the ring support 71 (the side closer to the pipe joint JT). In this embodiment, an example is shown in which a pair of bearings 70 are installed on the same abutment 91, one of which is a movable bearing 70M and the other is a fixed bearing 70F. The movable bearing 70M is configured to allow displacement of the ring support 71 in the pipe axis direction and to absorb expansion and contraction of the pipe. The fixed bearing 70F is configured to allow rotational displacement of the ring support 71 around a horizontal axis 72 perpendicular to the pipe axis direction and to absorb eccentricity and tilt of the pipe.

[0014] The pair of supports 70 are fitted with bridge fall prevention devices 73 that restrict movement of the pipe body 1 in the direction that extends the pipe joint JT. The bridge fall prevention device 73 comprises a connecting cable 74 that is inserted into a through hole provided in the ring support 71, and a stopper 75 that is provided at the end of the connecting cable 74 and prevents it from slipping out of the through hole. The connecting cable 74 is made of PC steel strands or the like extending in the axial direction of the pipe. The stopper 75 has a built-in coil spring (not shown) that generates a biasing force in a direction that suppresses slack in the connecting cable 74. The installation of the bridge fall prevention device 73 is optional and may be omitted.

[0015] The pipe joint JT is configured as an expansion joint that can expand and contract along the pipe axis direction, and absorbs displacement such as expansion and contraction of the water pipe bridge 90 in cooperation with a bearing 70. In the pipe joint JT, the ends of the pipes 1 are connected to each other via a flange 40. A main pipe section 41 of the flange 40 is disposed across the ends of the pair of pipes 1, and the gap between the main pipe section 41 and the ends of the pipes 1 is sealed with a sealant 42. In this embodiment, the ends of the pipes 1 are formed by short pipe sections 43 joined by welding. Therefore, the pipe joint JT is an expansion joint that includes the short pipe section 43 joined to the pipes 1 by welding, and the main pipe section 41 that is inserted outside the short pipe section 43 so as to be displaceable relative to the short pipe section 43 in the pipe axis direction.

[0016] 4 and 5 show the pipe body 1 detached from the pipe joint JT. In FIG. 4, the allowable expansion / contraction of the movable support 70M has been exceeded, causing the ring support 71 to fall from the movable support 70M. In some cases, the ring support 71 may break midway and fall. A step prevention structure may be applied to prevent a step from occurring on the road surface (the upper surface of the abutment 91) due to the ring support 71 falling. The step prevention structure may be formed, for example, with a block-shaped member equipped with a shock-absorbing rubber and can be retrofitted to the support 70. In FIG. 5, the pipe is bent via the pipe joint JT. In FIGS. 4 and 5, the bridge fall prevention device 73 (not shown in FIGS. 4 and 5) restricts the expansion of the pipe, but the sealant 42 has fallen off the pipe body 1. The flexible pipe 14 has the function of preventing water leakage to the outside of the device and maintaining water flow in such a situation.

[0017] As described above, if the pipeline elongates significantly beyond the expansion and contraction allowance of the pipe joint JT and the pipe body 1 comes off at the pipe joint JT, the accompanying deformation of the flexible pipe 14 maintains the sealed space inside the device, allowing water to flow. However, if the extension or displacement is large enough to overcome the restrictions imposed by the bearings 70 and the bridge fall prevention device 73, there is a risk that the pipe body 1 will fall off the bearings 70 and the flexible pipe 14 will come into contact with the abutment 91. According to the water leakage prevention structure of this embodiment, the flexible pipe 14 is made of metal, and the water leakage prevention device 10 is located within area X, so that the ring support 71 can act as a support in the event of detachment, thereby preventing malfunction due to damage to the flexible pipe 14.

[0018] As shown in FIG. 3, the water leakage prevention device 10 further includes a seal 11b that seals the gap between the pipe body 1 and the outer fitting member 11, and a press ring 50 that presses the seal 11b. The seal 11b is made of an elastic material such as rubber, as are the seals 12b and 42. The press ring 50 is connected to the outer fitting member 11 and is located within region X (see FIG. 2). A clearance is provided between the press ring 50 and the ring support 71 in the pipe axial direction. Similarly, a press ring 50 that presses the seal 12b is connected to the outer fitting member 12. Therefore, the seals 11b and 12b and the press ring 50 (including the pressing portion 51, connecting bolt 52, main body 53, etc. that constitute them) that press them are all located within region X.

[0019] As shown in FIG. 6, the outer fitting member 11 has a retaining portion 11a that retains the sealing material 11b, and an extension body 11c that extends in the pipe diameter direction. The retaining portion 11a is formed as a tubular body having an inner diameter dimension that allows it to be fitted onto the pipe body 1. In this embodiment, the outer fitting member 11 (the retaining portion 11a) has a female thread portion 11e into which a connecting bolt 52, which will be described later, is threaded. Therefore, the retaining portion 11a itself functions as a flange for connecting the connecting bolt 52. The thickness of the retaining portion 11a in the pipe diameter direction is set to be large enough to form the female thread portion 11e. The retaining portion 11a and the extension body 11c are integrated and are made of a metal material such as stainless steel.

[0020] In this embodiment, the retaining portion 11a is integrally formed with the extension body 11c and also serves as a flange to which the connecting bolt 52 is attached, so the gap between the extension body 11c and the flange is essentially zero. This allows the water leakage prevention device 10 to be configured compactly, which is convenient for arranging the device 10 in a narrow space within the region X. The thickness of the extension body 11c may be increased partially or entirely so that the extension body 11c also serves as a flange. The outer fitting member 12 has a retaining portion 12a that retains the sealing material 12b and an extension body 12c that extends in the pipe radial direction (see FIG. 3). The configuration of the outer fitting member 11 described in this specification can be similarly applied to the outer fitting member 12, so a detailed description of the outer fitting member 12 will be omitted.

[0021] As shown in FIG. 2, the water leakage prevention device 10 of this embodiment includes a tie rod 13 inserted through a rod hole formed in each of the extension body 11c of the outer fitting member 11 and the extension body 12c of the outer fitting member 12. The tie rod 13 has a restricting member 15 that restricts the relative movement of the tie rod 13 with respect to the extension bodies 11c, 12c. The restricting member 15 is formed by a nut threaded onto the male thread portion of the tie rod 13, and may also include a spacer and a washer. The position of the restricting member 15 on the tie rod 13 can be set appropriately taking into account the amount of relative movement of the tie rod 13 with respect to the extension bodies 11c, 12c. Note that the installation of the tie rod 13 is optional and may be omitted.

[0022] One end of the flexible pipe 14 is joined to the extension body 11c, and the other end is joined to the extension body 12c. The flexible pipe 14 is an expandable and flexible pipe that can follow the expansion and contraction and eccentricity of the pipeline. Therefore, if the pipe body 1 comes off at the pipe joint JT, the water leakage prevention device 10 may deform accordingly. In this embodiment, the flexible pipe 14 is made of a metal material (including alloys) such as stainless steel, carbon steel, iron, or copper. Among these, stainless steel is particularly preferred because of its strength, corrosion resistance, and ease of workability when formed into a corrugated pipe.

[0023] The flexible pipe 14 is formed of a corrugated pipe extending in a corrugated pattern along the pipe axis direction. More specifically, the flexible pipe 14 is formed of a bellows pipe having a bellows structure. In this embodiment, the flexible pipe 14, which is a bellows pipe, has a bellows structure in which low and high mountain shapes alternate. This configuration reduces interference during deformation and can absorb large displacements. However, this is not limited to this, and a bellows structure in which mountain shapes of uniform height are repeated may also be used. Furthermore, the corrugated pipe is not limited to a bellows pipe formed with alternating concave and convex shapes along the pipe axis direction, but a corrugated pipe formed with concave and convex shapes spirally along the pipe axis direction may also be used.

[0024] From the viewpoint of improving workability when joining to the extension body 11c, it is preferable that the end of the flexible pipe 14 extends straight along the pipe axis direction. In this embodiment, the end of the flexible pipe 14 joined to the extension body 11c is formed of a metal extension member 14E, which is a separate member from the main body formed as a corrugated pipe (see FIG. 6). The joining of the extension member 14E to the main body is performed by welding, but mechanical joining using bolts, rivets, etc. is also possible. The type of joint used when joining is not limited to a lap joint, and may be a butt joint, etc.

[0025] As shown in Figure 6, the pressure ring 50 includes a pressing portion 51 that presses the sealing material 11b, a main body portion 53 that is disposed away from the outer fitting member 11 in the pipe axis direction, and a connecting bolt 52 that connects the main body portion 53 to the outer fitting member 11. A through hole 53h is formed in the main body portion 53 as a clearance hole. The connecting bolt 52 inserted into the through hole 53h is threaded into the female thread portion 11e. Therefore, the main body portion 53 functions as a flange for connecting the connecting bolt 52. A nut 57 located on one side AD1 of the main body portion 53 in the pipe axis direction and a nut 58 located on the other side AD2 of the main body portion 53 in the pipe axis direction are attached to the connecting bolt 52.

[0026] In this embodiment, a separation prevention mechanism 60 is applied to prevent the tubular body 1 from separating from the outer fitting members 11, 12. The separation prevention mechanism 60 has a pressing bolt 59 as a locking portion that can be locked onto the outer circumferential surface of the tubular body 1 in the region X, and is provided integrally with the pressing ring 50. The pressing bolt 59 is threaded into a threaded hole provided in a portion that protrudes from the main body 53 toward one axial side AD1. A claw portion is formed at the tip of the pressing bolt 59 on the inner side in the diametrical direction of the tubular body, so that the claw portion can be locked onto the outer circumferential surface of the tubular body 1. The pressing bolts 59 are arranged at multiple locations around the circumferential direction of the tubular body. The separation prevention effect is achieved by having the pressing bolt 59 protrude inward in the diametrical direction of the tubular body and by firmly locking the claw portion at the tip of the pressing bolt 59 onto the outer circumferential surface of the tubular body 1.

[0027] The structure of the detachment prevention mechanism 60 is not particularly limited, and may be, for example, a structure as shown in FIG. 7. In the example shown in FIG. 7, the pressure bolt 59 is formed as a separate member from the pressure ring 50. The detachment prevention mechanism 60 has a connecting portion 62 that connects the pressure bolt 59 to the water leakage prevention device 10. The connecting portion 62 is composed of a bolt and nut. The bolt is threaded into a threaded hole provided in the extension body 11c. The pressure bolt 59, which serves as a locking portion, is connected to the outer fitting member 11 (the extension body 11c) via the connecting portion 62. The detachment prevention mechanism 60 is attached to the water leakage prevention device 10 without the pressure ring 50 interposed therebetween. This makes it possible to attach the detachment prevention mechanism 60 after the pressure ring 50 has been installed.

[0028] The pressure ring 50 is configured so that, when the nut 57 is rotated, the pressing portion 51 approaches the outer fitting member 11 and presses the sealing material 11b, thereby sealing the gap between the outer fitting member 11 and the tubular body 1. While Fig. 6 shows a state in which the nut 58 is in contact with the main body 53 and the pressing bolt 59 is engaged with the outer peripheral surface of the tubular body 1, the nut 58 is tightened and the pressing bolt 59 is engaged with the outer peripheral surface of the tubular body 1 after the pressure ring 50 is brought close to the outer fitting member 11 to seal the gap with the sealing material 11b. One side AD1 in the axial direction of the tube corresponds to the side opposite the direction in which the pressure ring 50 presses the sealing material 11b, and the other side AD2 in the axial direction of the tube corresponds to the side in the direction in which the sealing material 11b is pressed.

[0029] If the device becomes filled with water due to the removal of the pipe body 1 and water pressure is generated, an external force acts in the pipe axial direction, moving the outer fitting member 11 toward one side AD1 in the pipe axial direction (the side away from the pipe joint JT). If this external force causes the outer fitting member 11 to move relative to the pipe body 1, the gap between the pressure ring 50 and the outer fitting member 11 may decrease, causing overcompression of the sealing material 11b and uneven surface pressure. Therefore, in this embodiment, the relative movement of the connecting bolt 52 with respect to the main body 53 is restricted by a nut 58, thereby maintaining the gap between the outer fitting member 11 and the pressure ring 50. This prevents substantial changes in the compression state of the sealing material 11b and suppresses deterioration of sealing performance. Water filling the device can be discharged through a valve 9 (see FIG. 3).

[0030] The joint 43J of the short pipe section 43 is located within the region X, and the weld bead has been removed. This is convenient because the device 10 is not restricted by the weld bead when being placed in the narrow space within the region X. The traces of the removed weld bead extend along the circumferential direction of the pipe, and the outer circumferential surface of the joint 43J is formed by a smoothly curved surface. When the seal materials 11b, 12 are placed outside the joint 43J (the side away from the pipe joint JT), the weld bead does not necessarily have to be removed, but in many cases there is not enough space to allow this. Therefore, it is preferable to remove the weld bead as in this embodiment, from the viewpoint of avoiding interference with the seal materials 11b, 12b and the pressure ring 50.

[0031] In this embodiment, a water leakage prevention device 10 is also arranged in an area X sandwiched between a pair of supports 70 in the same pier 92 (see FIG. 1). The water leakage prevention structure in the pier 92 can be configured in the same way as the water leakage prevention structure in the abutment 91 described above, so a duplicated explanation will be omitted.

[0032] In the method for preventing water leakage from an aqueduct bridge of this embodiment, a water leakage prevention device 10 is attached to a pipe joint JT to prevent water leakage due to separation of a pipe body 1, and the water leakage prevention device 10 is placed in an area X sandwiched between a pair of supports 70 on the same abutment 91 (or the same pier 92). The method preferably includes a step of attaching a sealant 11b to the gap between the pipe body 1 and an outer fitting member 11, and pressing the sealant 11b with a press ring 50 connected to the outer fitting member 11 and placed in the area X. The method also preferably includes a step of removing a weld bead from a joint 43J of a short pipe section 43 placed in the area X. One specific example will now be described with reference to FIGS. 8 to 10.

[0033] 8 to 10 are diagrams showing the process of installing the water leakage prevention device 10. Although bearings 70 and ring supports 71 are arranged on both sides of the pipe joint JT, they are not shown. First, as shown in FIG. 8, the outer fitting members 11 and 12 are fitted onto the pipe body 1. However, in this embodiment, prior to installing the outer fitting members 11 and 12, the weld beads at the joints 43J (not shown in FIGS. 8 to 10) of the short pipe sections 43 are removed. At the same time, the paint on the outer surface of the pipe body 1 at the installation locations of the outer fitting members 11 and 12 is also removed. These operations can be performed using a grinding tool such as a grinder.

[0034] When attaching the outer fitting member 11 to the pipe body 1, as shown in Figures 8(A) to 8(C), the semicircular arc-shaped segment 11X is lifted by a crane, placed over the pipe body 1, and placed in a predetermined position. The similarly semicircular arc-shaped segment 11Y is then set to form a ring shape, and the end faces of the segments 11X and 11Y are butted together at the joint 11Z, which is then welded together. A jig is used as needed to position and center the segments 11X and 11Y. In Figure 8(C), fasteners (bolts and nuts) are attached across the joint 11Z to temporarily secure the segments 11X and 11Y, but these may be removed after the joint 11Z is joined. The outer fitting member 12 can be attached in the same manner as the outer fitting member 11.

[0035] Next, the flexible pipe 14 is attached so as to surround the pipe joint JT. Specifically, as shown in Figures 9(A) to 9(C), a semicircular arc-shaped segment 14X is lifted by a crane, placed over the pipe body 1, and placed in a predetermined position. Then, a similar semicircular arc-shaped segment 14Y is set in place to form a circular ring. At this stage, the joints 14Z where the end faces of the segments 14X and 14Y butt against each other are not yet joined. Since the flexible pipe 14, which is not yet joined to the multiple segments 14X and 14Y, is placed between the outer fitting member 11 and the outer fitting member 12, it is preferable to temporarily fix them by tack welding or the like.

[0036] Next, gas leakage tape or yarn is used to seal the gap between the inner circumferential surface of the outer fitting member 11 and the outer circumferential surface of the pipe 1, the gap between the inner circumferential surface of the outer fitting member 12 and the outer circumferential surface of the pipe 1, and the joint 14Z, and then a shielding gas is injected into the internal space of the flexible pipe 14. The shielding gas is an inert gas such as argon gas, which is necessary for welding the joint 14Z. In this embodiment, the shielding gas is injected through a communication hole 7 (see FIG. 6) provided in the extension member 14E of the flexible pipe 14. After the injection of the shielding gas is completed, a plug 8 (see FIG. 6) is attached to close the communication hole 7. The communication hole 7 can also be provided in the outer fitting members 11 and 12.

[0037] After the shielding gas is injected, the multiple divided pieces 14X, 14Y are welded together and integrated from the outside of the flexible pipe 14. At this time, a welding torch is brought close to the joint 14Z from the outside of the flexible pipe 14. Because the thickness of the flexible pipe 14 is relatively small, when the welding torch is brought close, the heat of the arc melts not only the outer circumferential surface of the joint 14Z but also the inner circumferential surface. The outer circumferential surface of the joint 14Z is covered with the shielding gas supplied from the welding torch, and the inner circumferential surface of the joint 14Z is covered with the shielding gas that has been injected into the flexible pipe 14 in advance. This ensures appropriate welding quality for the joint 14Z.

[0038] After joining the joint 14Z, one end of the flexible pipe 14 is joined to the extension body 11c by welding, and the other end is joined to the extension body 12c by welding. In this way, the flexible pipe 14 is formed by joining together by welding a plurality of (two in this embodiment) segmented pieces 14X, 14Y that are divided in the circumferential direction of the pipe, and has a segmented structure that can be fitted onto an existing pipeline. In this embodiment, an example is shown in which the outer fitting member 11, the outer fitting member 12, and the flexible pipe 14 are each composed of two segmented pieces, but the number of segmented pieces that make them up is not particularly limited.

[0039] In this embodiment, the outer fitting member 11, the outer fitting member 12, and the flexible pipe 14 are attached in this order, but this is not limited to this. For example, the flexible pipe 14 may be attached first, and then the outer fitting member 11 and the outer fitting member 12 may be positioned so that the flexible pipe 14 is sandwiched between them, and then they may be joined by welding. The welding procedure is not limited to the above. For example, the segments 11X and 11Y may be joined to the segments 14X and 14Y, respectively, by welding in advance, and the same applies to the segments that make up the outer fitting member 12.

[0040] Next, as shown in FIG. 10(A), the divided pressure ring 50 is fitted onto the tubular body 1, and the sealing material 11b is arranged in an annular shape along the outer circumferential surface of the tubular body 1. The sealing material 11b is arranged in an annular shape by wrapping a strip-shaped member around the circumferential direction of the pipe and gluing its ends together. The portion of the pressure ring 50, including the pressing portion 51 and the main body portion 53, consists of multiple divided pieces each having a semicircular arc shape. These are combined to form an annular shape, and then the end faces of the divided pieces are butted together and joined by welding. The jig 80 is fixed to the side of the extension body 11c by welding. The jig 80 is left in place, but may be removed after being used to position and center the outer fitting member 11. A connecting bolt 52 with a nut 58 attached is threaded into the female thread portion 11e of the outer fitting member 11. A double-threaded bolt (or stud bolt or stud bolt) is preferably used as the connecting bolt 52.

[0041] 10(B), a nut 57 is attached to the connecting bolt 52 inserted through the through-hole 53h of the main body 53, and the main body 53 is moved closer to the outer fitting member 11 by rotating the nut 57. During this time, the nut 58 is moved toward the other axial side AD2 so as not to come into contact with the main body 53. The tip of the pressing bolt 59 has not yet engaged with the outer peripheral surface of the pipe body 1. The sealing material 11b is pressed along the axial direction by the pressing part 51, which moves together with the main body 53, to seal the gap between the inner peripheral surface of the outer fitting member 11 and the outer peripheral surface of the pipe body 1. By controlling the tightening torque of the nut 57, the sealing material 11b can be compressed appropriately while maintaining uniform surface pressure, thereby achieving the desired sealing performance.

[0042] 10(C), the nut 58 is brought into contact with the main body 53, restricting the relative movement of the connecting bolt 52 with respect to the main body 53. This maintains the distance between the outer fitting member 11 and the press ring 50 even when an external force acts in the pipe axial direction to move the outer fitting member 11 away from the pipe joint JT. Nuts 58 do not need to be attached to all connecting bolts 52 around the pipe circumference; they may be attached at appropriate intervals, for example, at four locations around the pipe circumference. After connecting the press ring 50 to the outer fitting member 11, the press bolt 59 is operated to lock its tip against the outer peripheral surface of the pipe body 1.

[0043] As described above, the sealing material 11b attached to the outer fitting member 11 is sealed with the press ring 50. In this embodiment, the sealing material 12b attached to the outer fitting member 12 is sealed with the press ring 50 in the same manner as the outer fitting member 11. Therefore, the connection structure that connects the outer fitting member 12 to the press ring 50 is configured to maintain the distance between the outer fitting member 12 and the press ring 50 even when an external force in the pipe axial direction acts to move the outer fitting member 12 away from the pipe joint JT, and as a result, deterioration in the sealing performance of the outer fitting member 12 is also suppressed. Then, by attaching tie rods 13 to the outer fitting members 11 and 12 and further attaching a bridge fall prevention device 73, the leakage prevention structure for the aqueduct bridge shown in Figure 2 is obtained.

[0044] The water leakage prevention device 10 attached to the pipeline in this way is positioned within the area X sandwiched between a pair of supports 70 on the same abutment 91. After the water leakage prevention device 10 is attached to the pipeline, it is desirable to conduct a test at the construction site to confirm the quality of the welded parts. One possible test is to fill the flexible pipe 14 with water and perform a water pressure test. However, depending on the environment of the construction site, there is a risk that drainage after the test will be hindered. In such cases, instead of a water pressure test, an airtightness test may be performed using a gas (for example, a shielding gas such as argon gas, or nitrogen gas) injected into the flexible pipe 14. After the test, the necessary areas are painted and the construction is completed.

[0045] [Second embodiment] Next, a second embodiment will be described with reference to Fig. 11. The second embodiment can be configured similarly to the first embodiment except for the configuration described below, so a description of the commonalities will be omitted and differences will be mainly described. The same reference numerals will be used to designate components already described in the first embodiment, and duplicated descriptions will be omitted.

[0046] In the first embodiment described above, a pair of bearings 70 are installed on the same abutment 91, and the water leakage prevention device 10 is arranged in the area X sandwiched between the pair of bearings 70, whereas in the second embodiment, a single bearing 70 is installed on the same abutment 91, and the water leakage prevention device 10 is arranged in the area X sandwiched between the bearing 70 on the same abutment 91 and the fixed support end 90E of the water pipe bridge 90. Even in this structure, the flexible pipe 14 is made of metal, and the water leakage prevention device 10 is arranged in the area X, so that the ring support 71 can act as a support when it falls off, and therefore, as in the first embodiment, malfunction due to damage to the flexible pipe 14 can be suppressed.

[0047] In the example shown in FIG. 11 , a recess 93 is formed on the upper surface of the abutment 91, recessed downward below the installation surface of the bearing 70. The recess 93 is arranged in the region X so as to face the flexible pipe 14. This configuration reduces the risk of the flexible pipe 14 coming into contact with the abutment 91 and being damaged, which is advantageous in preventing malfunctions due to damage to the flexible pipe 14. The recess 93 is also useful in ensuring the working space required for construction. Such a recess 93 can also be formed in the region X sandwiched between a pair of bearings 70 as shown in the first embodiment.

[0048] [Modification of the separation prevention mechanism] Modified examples of the separation prevention mechanism 60 will be described with reference to Figures 12 to 15. These separation prevention mechanisms 60 are applicable to both the first and second embodiments, and are useful for arranging the water leakage prevention device 10 in a smaller space within the area X. The same reference numerals are used for the components already described in the above embodiments, and duplicated explanations will be omitted.

[0049] In the example shown in FIG. 12, the detachment prevention mechanism 60 has a locking portion 61 that can be locked to the outer circumferential surface of the pipe body 1 outside the region X, and a connecting portion 62 that extends in the pipe axial direction across the ring support 71 and connects the locking portion 61 to the water leakage prevention device 10. The locking portion 61 is equipped with a pressing bolt configured similarly to the pressing bolt 59 described above. The connecting portion 62 is made up of a bolt and nut. The connecting portion 62 connects the locking portion 61 to (the main body portion 53 of) the pressing ring 50, but may also be connected to (the extension body 11c of) the outer fitting member 11 as shown in FIG. 14.

[0050] In the example shown in FIG. 13, the separation prevention mechanism 60 has a fixing part 63 whose position in the pipe axis direction relative to the ring support 71 is fixed, and a connecting part 64 that connects the fixing part 63 to the water leakage prevention device 10. This configuration is expected to provide a stronger separation prevention effect than a mechanism that uses a pressing bolt such as the locking part 61. The fixing part 63 is configured to be able to clamp the ring support 71 along the pipe axis direction. The connecting part 64 is made up of a bolt and nut. The connecting part 64 connects the fixing part 63 to the pressing ring 50, but it may also be connected to the outer fitting member 11 as shown in FIG. 14.

[0051] In the example shown in Figure 14, the separation prevention mechanism 60 has a fixing part 65 whose position in the pipe axial direction relative to the ring support 71 is fixed, and a connecting part 66 that connects the fixing part 65 to the water leakage prevention device 10. The fixing part 65 is fixed to the ring support 71 by welding. Because the fixing part 65 is fixed to the ring support 71 rather than the pipe body 1, the impact of welding on the inner surface paint of the pipe body 1 is reduced. The connecting part 66 is composed of bolts and nuts, one of which, a nut 67, is fixed to the extension body 11c by welding. The connecting part 66 connects the fixing part 65 to the outer fitting member 11, but it may also be connected to the press ring 50 as shown in Figures 12 and 13.

[0052] In the example shown in Figure 15, the separation prevention mechanism 60 has a fixing part 68 whose position in the pipe axis direction relative to the ring support 71 is fixed, and a connecting part 69 that connects the fixing part 68 to the water leakage prevention device 10. The fixing part 68 is fixed to the ring support 71 by welding. Moreover, the members that make up the fixing part 68 are fixed to the pressure ring 50 by welding or the like, or are provided integrally with the pressure ring 50, so that the fixing part 68 also functions as the connecting part 69. The fixing part 68 is not limited to being fixed to the inside of the ring support 71, and may be fixed to the outside or outer peripheral surface of the ring support 71, as is the case with the fixing part 65 described above.

[0053] [Other variations] In the above-described embodiment, the pipe joint JT has an example of a sleeve joint structure in which the ends of the pipes 1 are connected to each other via a flange 40, but this is not limiting. For example, a joint structure in which one pipe is connected by fitting a spigot formed at the end of the other pipe into a socket formed at the end of the other pipe may also be used. In such a case, it is preferable to use an expansion joint that is configured to be expandable and contractible in the pipe axial direction between the socket and spigot.

[0054] In the above-described embodiment, an example was shown in which the telescopic cover was a flexible pipe 14, but this is not limited to this, and any telescopic tubular body that surrounds a pipe joint can be used without any particular restrictions. Therefore, for example, it is also possible to use, as the telescopic cover, an telescopic pipe that includes a first cylindrical body, a second cylindrical body inserted into the first cylindrical body, and an annular sealing material that seals the gap between them, and in which the first cylindrical body and the second cylindrical body are configured to be relatively movable along the pipe axial direction.

[0055] In the above-described embodiment, the outer fitting member 11 is watertightly fitted onto the pipe 1 via the sealing material 11b, but this is not limiting. For example, it is also possible to weld the inner end of the outer fitting member 11 in the pipe diameter direction to the outer peripheral surface of the pipe 1 without using the sealing material 11b, thereby achieving watertight fitting. With this configuration, the press ring 50 is not required and the water leakage prevention device is more compact, which is advantageous for arranging the device in a smaller space within the region X. The same applies to the outer fitting member 12.

[0056] The structures of the outer fitting members 11, 12 and the press ring 50, and the connection structure between the outer fitting members 11, 12 and the press ring 50 are not particularly limited, and various modified examples can be applied. In the above-described embodiment, an example was shown in which the connecting bolt 52 of the press ring 50 is threaded into the female thread portion 11e of the outer fitting member 11, but this is not limited to this. For example, instead of the female thread portion 11e, the connecting bolt 52 may be inserted into a flange rising from the retaining portion 11a, and the relative movement of the connecting bolt 52 with respect to the flange may be restricted by a nut or the like. Even with this configuration, the connection structure maintains the distance between the outer fitting member 11 and the press ring 50 when an external force is applied in the pipe axial direction.

[0057] It will be understood by those skilled in the art that the above-described embodiments are examples of the following aspects.

[0058] [1] The water leakage prevention structure for an aqueduct bridge according to the present disclosure is a structure in which a water leakage prevention device is attached to a pipe joint connecting the ends of pipes forming the pipeline of the aqueduct, the water leakage prevention device preventing water leakage due to separation of the pipes, the water leakage prevention device having a metal telescopic cover surrounding the pipe joint and external fitting members joined to both ends of the telescopic cover in the pipe axis direction and externally fitted watertightly to the pipes, the water leakage prevention device being arranged in an area sandwiched between a pair of bearings on the same abutment or the same pier, or in an area sandwiched between a bearing on the same abutment and a fixed support end of the aqueduct bridge, thereby making it possible to prevent malfunctions due to damage to the telescopic cover.

[0059] [2] In the water leakage prevention structure of [1] above, the water leakage prevention device may further have a sealing material that seals the gap between the pipe body and the outer fitting member, and a pressure ring that presses the sealing material, and the pressure ring may be connected to the outer fitting member and positioned within the area.

[0060] [3] In the water leakage prevention structure of [1] or [2] above, the pipe joint may be an expansion joint having a short pipe section joined to the pipe body by welding and a main pipe section inserted outside the short pipe section so as to be displaceable relative to the short pipe section in the pipe axial direction, and the joint point of the short pipe section may be located within the region and the weld bead may be removed.

[0061] [4] In any one of the water leakage prevention structures [1] to [3] above, a separation prevention mechanism may be applied that prevents the pipe body from separating from the outer fitting member.

[0062] [5] In the water leakage prevention structure of [4] above, the support may support the pipe body via a ring support fixed to the outer peripheral surface of the pipe body, and the detachment prevention mechanism may have a locking portion that can be locked to the outer peripheral surface of the pipe body outside the area, and a connecting portion that extends across the ring support in the pipe axis direction and connects the locking portion to the water leakage prevention device.

[0063] [6] In the water leakage prevention structure of [4] above, the support may support the pipe body via a ring support fixed to the outer surface of the pipe body, and the detachment prevention mechanism may have a fixing part whose relative position in the pipe axis direction with respect to the ring support is fixed, and a connecting part that connects the fixing part to the water leakage prevention device.

[0064] [7] The method for preventing water leakage from an aqueduct bridge according to the present disclosure comprises attaching a water leakage prevention device to a pipe joint connecting the ends of pipes forming the pipeline of the aqueduct bridge, thereby preventing water leakage due to the separation of the pipes, wherein the water leakage prevention device has a metal telescopic cover that surrounds the pipe joint, and external fitting members that are joined to both ends of the telescopic cover in the pipe axis direction and are watertightly fitted onto the pipes, and the water leakage prevention device is placed within an area sandwiched between a pair of bearings on the same abutment or pier, or within an area sandwiched between a bearing on the same abutment and a fixed support end of the aqueduct bridge. This makes it possible to prevent malfunctions due to damage to the telescopic cover.

[0065] [8] The method for preventing water leakage [7] above may include a step of fitting a sealing material in the gap between the pipe body and the outer fitting member, and pressing the sealing material with a pressure ring connected to the outer fitting member and placed within the area.

[0066] [9] In the leakage prevention method of [7] or [8] above, the pipe joint is an expansion joint having a short pipe section joined to the pipe body by welding and a main pipe section that is inserted outside the short pipe section so as to be displaceable relative to the short pipe section in the pipe axial direction, and the method may also include a step of removing the weld bead at the joint of the short pipe section located within the area.

[0067] Although the embodiments of the present disclosure have been described, the specific configurations are not limited to these embodiments. The present disclosure is not limited to the above-described embodiments, and various improvements and modifications are possible within the scope of the present disclosure. The configurations described in the above-described embodiments may be adopted in any combination. [Explanation of symbols]

[0068] 1. Body 10 Water leak prevention device 11 Outer fitting member 11b Sealing material 12 Outer fitting member 12b Sealing material 14 Flexible pipe (an example of a telescopic cover) 41 Main Pipe 43 Short pipe section 43J Joint 50 Push Ring 60 Anti-detachment mechanism 70 Bearing 71 Ring Support 90 Aqueduct Bridge 90E fixed support end 91 Abutment 92 Bridge Pier JT Pipe Fittings 61 Locking part 62,64,66,69 Connection part 63,65,68 Fixed part

Claims

1. In a water pipe bridge water leakage prevention structure, a water leakage prevention device is attached to a pipe joint connecting the ends of pipes forming the pipeline of the water pipe bridge, to prevent water leakage due to separation of the pipes. The water leakage prevention device includes a metal telescopic cover that surrounds the pipe joint, and an outer fitting member that is joined to both ends of the telescopic cover in the pipe axial direction and is watertightly fitted onto the pipe body, A water leakage prevention structure for an aqueduct bridge, characterized in that the water leakage prevention device is arranged within an area sandwiched between a pair of supports on the same abutment or pier, or within an area sandwiched between a support on the same abutment and the fixed support end of the aqueduct bridge.

2. The water leakage prevention device further includes a sealant that seals a gap between the pipe body and the outer fitting member, and a press ring that presses the sealant, The water leakage prevention structure for a water pipe bridge according to claim 1, wherein the pressure ring is connected to the outer fitting member and is arranged within the region.

3. the pipe joint is an expansion pipe joint including a short pipe section joined to the pipe body by welding, and a main pipe section inserted externally so as to be displaceable relative to the short pipe section in the pipe axial direction, 2. The water leakage prevention structure for an aqueduct bridge according to claim 1, wherein the joints of the short pipe sections are arranged within the area and the weld beads are removed.

4. A water leakage prevention structure for a water pipe bridge according to any one of claims 1 to 3, wherein a separation prevention mechanism is applied to prevent the pipe body from separating from the outer fitting member.

5. the bearing supports the pipe via a ring support fixed to an outer peripheral surface of the pipe, The water leakage prevention structure for a water pipe bridge as described in claim 4, wherein the detachment prevention mechanism has a locking portion that can be locked to the outer surface of the pipe body outside the area, and a connecting portion that extends in the pipe axial direction across the ring support and connects the locking portion to the water leakage prevention device.

6. the bearing supports the pipe via a ring support fixed to an outer peripheral surface of the pipe, The water leakage prevention structure for a water pipe bridge as described in claim 4, wherein the detachment prevention mechanism has a fixed part whose relative position in the pipe axis direction with respect to the ring support is fixed, and a connecting part that connects the fixed part to the water leakage prevention device.

7. A method for preventing water leakage from an aqueduct bridge, in which a water leakage prevention device is attached to a pipe joint connecting the ends of pipes forming the pipeline of the aqueduct bridge, to prevent water leakage due to separation of the pipes, The water leakage prevention device includes a metal telescopic cover that surrounds the pipe joint, and an outer fitting member that is joined to both ends of the telescopic cover in the pipe axial direction and is watertightly fitted onto the pipe body, A method for preventing water leakage from an aqueduct bridge, characterized in that the water leakage prevention device is placed in an area sandwiched between a pair of supports on the same abutment or pier, or in an area sandwiched between a support on the same abutment and the fixed support end of the aqueduct bridge.

8. 8. A method for preventing water leakage from a water pipe bridge as described in claim 7, including a step of fitting a sealing material in the gap between the pipe body and the outer fitting member, and pressing the sealing material with a pressure ring connected to the outer fitting member and placed within the area.

9. the pipe joint is an expansion pipe joint including a short pipe section joined to the pipe body by welding, and a main pipe section inserted externally so as to be displaceable relative to the short pipe section in the pipe axial direction, 9. The method for preventing water leakage from an aqueduct bridge according to claim 7 or 8, further comprising the step of removing weld beads at the joints of the short pipe sections arranged in the region.

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