JP7698849B2 - Rigid formwork material for use in cable corner bend buffer structure and function variable construction method for cable corner bend buffer structure - Google Patents

Description

The present invention relates to a cable bend buffer structure installed at the anchorage of a cable stretched across a bridge, and more specifically, to a rigid formwork material and construction method that allows the function of the cable bend buffer structure to be changed.

Cables stretched across bridges such as cable-stayed bridges and Nielsen bridges can move due to factors such as the weight fluctuation of vehicles traveling over the bridge, generating bending stress at the anchoring points where the cables are fixed; this phenomenon is called corner bending. As a measure to prevent corner bending, a cable corner bending buffer structure is provided at the cable's anchoring point, where a corner bending buffer material (cushion material) is installed between the cable and the anchoring pipe that surrounds the cable's outer circumference, and the elastic force of the corner bending buffer material is used to receive and suppress the cable's displacement, thereby preventing corner bending.

On the other hand, cables vibrate spontaneously and periodically due to the influence of wind, etc., and cable vibration control devices are installed to suppress this cable vibration. Cable vibration control devices, for example, are configured with a vibration control member made of a viscoelastic rubber member or oil, etc., interposed between a fixed part fixed to an anchoring pipe or bridge girder, etc., and a cable-side fixed part fixed to the cable, and the force of the cable vibration is transmitted to the vibration control member, and the vibration is damped by the resistance force of the vibration control member.

JP 2000-3285a7 A JP 2020-63619 A

The cable corner bend buffer structure prevents the cable from bending at its corners, and furthermore, the vibration damping effect of the corner bend buffer itself can suppress the cable vibration. However, depending on the environment and traffic conditions at the actual bridge installation site, the vibration damping effect of the corner bend buffer may not be enough to suppress the cable vibration. In such cases, it is effective to install a cable vibration damping device on the cable. Since the cable vibration damping device is usually installed on the cable within a range of several meters from the tip of the anchoring pipe, if the corner bend buffer is left in the anchoring pipe, the movement of the cable at the position of the cable vibration damping device will be restricted to a certain extent, and the vibration damping effect of the cable vibration damping device will not be fully exerted. Therefore, when installing a cable vibration damping device on the cable, all the corner bend buffer material in the anchoring pipe is removed, and the corner bend buffer material with a certain gap is installed again around the outer periphery of the cable, but this work is time-consuming and expensive.

The present invention has been made in consideration of the above circumstances, and aims to provide a cable corner bend buffer structure that suppresses corner bends and, when a cable vibration damping device is installed on the cable and used in combination, makes it possible to change the function of the structure to one that does not interfere with the function of the cable vibration damping device. In other words, in order to achieve the above objective, the present invention provides a rigid formwork material used in the cable corner bend buffer structure and a function variable construction method for the cable corner bend buffer structure.

The hard formwork material used in the cable corner bend buffer structure according to the present invention is
A rigid formwork material used for a cable corner-breaking buffer structure in which a corner-breaking buffer material is installed between the cable and an anchoring pipe surrounding the outer periphery of the cable at the anchoring portion of the cable stretched on a bridge,
A plurality of members are arranged in the circumferential direction of the cable to form a cylindrical shape along the outer circumferential surface of the cable, and the cable is detachably disposed between the cable and the corner-folding cushioning material,
When left between the cable and the corner-breaking cushioning material, the cable displacement and vibration are transmitted to the corner-breaking cushioning material, and when removed from between the cable and the corner-breaking cushioning material, a corner-breaking cushioning material with a gap is formed, with an annular gap between the cable and the corner-breaking cushioning material.

The function variable construction method of the cable corner bend buffer structure according to the present invention is as follows:
This is a construction method that makes it possible to change the function of a cable corner-breaking buffer structure in which a corner-breaking buffer material is installed between the cable and an anchoring pipe that surrounds the outer periphery of the cable at the anchoring portion of the cable stretched on a bridge,
A first cable corner-break cushioning structure is constructed in which the rigid formwork material according to claim 1 is disposed around the cable portion surrounded by the anchoring pipe so as to cover the entire outer circumference of the cable, a corner-break cushioning material is installed in the annular space between the rigid formwork material and the anchoring pipe, and the rigid formwork material is left between the cable and the corner-break cushioning material so that the displacement and vibration of the cable are transmitted to the corner-break cushioning material via the rigid formwork material,
When a cable vibration control device is installed and used in combination with a cable, the rigid formwork material in the first cable corner bend cushioning structure is removed to form a corner bend cushioning material with a gap that provides an annular gap between the cable and the corner bend cushioning material, and a second cable corner bend cushioning structure is constructed so as not to interfere with the function of the cable vibration control device.

According to the above configuration of the present invention, in a cable corner-breaking buffer structure in which a rigid formwork material is left between the cable and the corner-breaking buffer material, the displacement of the cable acting on the cable's fixing point is transmitted to the corner-breaking buffer material via the rigid formwork material, suppressing the cable's corner-breaking. In addition, the spontaneous and periodic vibration of the cable (hereinafter referred to as cable vibration) is transmitted to the corner-breaking buffer material via the rigid formwork material, and can be suppressed by the vibration damping effect of the corner-breaking buffer material itself.

In addition, in a cable corner-break cushioning structure in which the rigid formwork material has been removed and replaced with a corner-break cushioning material with gaps, a cable vibration damping device can be set up for the cable to suppress cable vibrations that could not be suppressed by the corner-break cushioning material. In other words, the corner-break cushioning material with gaps can be prevented from exerting a restraining force against cable vibrations by the gaps, so as not to interfere with the function of the cable vibration damping device. Therefore, the cable vibration damping device can suppress cable vibrations without being affected by the corner-break cushioning material. When the cable sways significantly and displacement occurs, the displacement of the cable is transmitted to the corner-break cushioning material with gaps, suppressing corner bending of the cable.

Therefore, according to the present invention, the cable corner bend cushioning structure has the effect of suppressing corner bends, but when a cable vibration damping device is installed on the cable and used in combination, the function can be changed to a structure that does not interfere with the function of the cable vibration damping device. In addition, the corner bend cushioning material with gaps contributes to extending the life of the cable vibration damping device by suppressing overload on the vibration damping device due to excessive cable displacement, and can also function as a fail-safe after the cable vibration damping device deteriorates.

1 is a schematic cross-sectional view showing a cable corner bend cushioning structure (first cable corner bend cushioning structure) in an embodiment. FIG. 2A and 2B are schematic cross-sectional views showing a first cable corner bend cushioning structure (FIG. 2A) and a second cable corner bend cushioning structure (FIG. 2B). FIG. 2 is an external view showing a rod-shaped formwork material that constitutes a part of a rigid formwork material. FIG. 2 is an external view showing a covered formwork material that constitutes a part of a hard formwork material. 10 is a process diagram for explaining a construction method of the first cable corner bend cushioning structure. FIG. FIG. 11 is a process diagram for explaining a construction method of the second cable corner bend cushioning structure. FIG. 2 is a schematic cross-sectional view showing a cable corner bend cushioning structure (second cable corner bend cushioning structure) in the embodiment.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings.
The cable corner break buffer structure in the embodiment is a structure that is provided at the cable anchoring part of the bridge girder or tower where the end of the cable stretched across the bridge is fixed, and suppresses the corner breakage of the cable. Here, in this specification, "corner break" refers to a phenomenon in which the cable moves due to the weight fluctuation of the vehicle running on the bridge, etc., and bending stress is generated at the anchoring point where the cable is fixed. Also, "cable vibration" described later refers to a phenomenon in which the cable spontaneously and periodically vibrates due to the influence of wind, etc.
As shown in Fig. 1, the cable corner-breaking buffer structure 1 includes a cable 10 stretched across a bridge, a cylindrical anchoring pipe 13 fixed to a bridge girder (fixed portion) 11 and surrounding the outer periphery of the end of the cable 10, and a corner-breaking buffer material 2 installed in the annular space between the cable 10 and the anchoring pipe 13 within the anchoring pipe 13, and a hard formwork material 3 is detachably disposed between the cable 10 and the corner-breaking buffer material 2. Note that, in this embodiment, an application example in which the corner-breaking buffer material is filled and installed in a cable-stayed bridge is shown, but the present invention is not limited to cable-stayed bridges, and can be applied to bridges in which the cable 10 is stretched, such as Nielsen bridges and suspension bridges. The corner-breaking buffer material 2 is not limited to construction in which a liquid is filled, and can be applied to construction in which a corner-breaking buffer structure is formed in the anchoring pipe 13, such as by inserting and installing a solid molded object.

A disk-shaped cable hat 14 is attached to the cable 10 near the opening of the anchoring pipe 13. This cable hat 14 blocks water from running down the cable 10 and prevents water from entering the cable anchoring section. Also, by attaching the cable hat 14 close to the rigid formwork material 3, it is possible to prevent the rigid formwork material 3 from floating up. Note that instead of the cable hat 14, a conical cable cover (not shown) may be installed to fit between the outer periphery of the opening of the anchoring pipe 13 and the outer periphery of the cable 10.

The cable 10 is configured by bundling a number of steel wires and covering them with a resin sheathing tube such as polyethylene. The cable 10 may be various bridge cables such as a bundle of plated steel wires in parallel, or a bundle of steel wires solidified with resin into a rod shape. Each end of the cable 10 is fixed to the bridge girder 11 and tower 12 by an anchor, and the bridge girder 11 is supported by the cable 10 stretched between the bridge girder 11 and the tower 12. The anchoring pipe 13 is made of a steel cylinder and is fixed to the bridge girder 11, which serves as the fixed part. The end of the cable 10 fixed to the bridge girder 11 is inserted into the anchoring pipe 13. The anchoring pipe 13 may be an anchoring pipe fixed to the tower 12, which serves as the fixed part. The corner-breaking buffer material 2 is made of a cushioning material having rubber elasticity such as polybutadiene.

When the cable 10 moves and displaces due to factors such as changes in the weight of vehicles traveling on the bridge, the cable corner bend buffer structure 1 uses the elastic force of the corner bend buffer material 2 to receive and suppress the displacement of the cable 10, and can suppress corner bending at the anchoring point of the cable 10. In addition, when cable vibration occurs in which the cable 10 sways spontaneously and periodically due to the effects of wind, rain, etc., the cable corner bend buffer structure 1 can dampen the vibration and suppress cable vibration using the material properties of the corner bend buffer material 2 itself. However, if it is found through observation that the vibration damping effect of the corner bend buffer material 2 is not enough to sufficiently suppress cable vibration depending on the environment, traffic conditions, etc. at the actual bridge installation site, it becomes necessary to install a cable vibration control device 6 on the cable 10.

In this embodiment, the cable corner bend buffer structure 1 is configured to have a variable function so that it can be used in combination with a cable vibration damping device installed on the cable 10. Here, in this specification, "variable function" (also referred to as "changing function" in the specification) refers to changing the function of the cable corner bend buffer structure 1 from one in which the corner bend buffer material 2 suppresses corner bends of the cable 10 and also suppresses cable vibration due to the material properties of the corner bend buffer material 2 to one in which the corner bend buffer material 2 (corner bend buffer material with gaps) suppresses corner bends of the cable 10, but does not exert a restraining force against cable vibration, and the vibration damping performance of the cable vibration damping device 6 to be installed later is maximized. Also, the "variable function construction method" described later refers to a construction method for varying the function in the cable corner bend buffer structure 1.
To make this function variable, a hard formwork material 3 is detachably disposed between the cable 10 and the corner-breaking buffer material 2. That is, as shown in FIG. 2, a first cable corner-breaking buffer structure 1A (see FIG. 2(A)) in which the hard formwork material 3 is left between the cable 10 and the corner-breaking buffer material 2, and a second cable corner-breaking buffer structure 1B (see FIG. 2(B)) in which the hard formwork material 3 is removed to form an annular gap 5 between the cable 10 and the corner-breaking buffer material 2 can be constructed. The size of the "gap 5" can be set arbitrarily within a range that does not lose the effect of suppressing corner bending of the cable 10. As an example, the size of the "gap 5" may be calculated from the allowable bending angle at the fixing point of the cable 10.

The rigid formwork material 3 is a combination of multiple members arranged in the circumferential direction of the cable 10, and has a tubular shape that follows the outer circumferential surface of the cable 10. The length of the rigid formwork material 3 in the cable axial direction is set to be equal to or greater than the length of the corner-bending buffer material 2 in the cable axial direction. Specifically, as shown in FIG. 2(A), the rigid formwork material 3 is composed of multiple rod-shaped formwork materials 31 arranged along the outer circumferential surface of the cable 10, and multiple covering formwork materials 32 arranged to cover the outer circumferential surfaces of the multiple rod-shaped formwork materials 31.

As shown in FIG. 3, the rod-shaped formwork material 31 is a long, thin, flat member having a rectangular cross section. The rod-shaped formwork material 31 is made of a hard material such as carbon steel or alloy steel (e.g., SUS304). The material of the rod-shaped formwork material 31 may be any material having a hardness equal to or greater than that of the cable 10, and may be other metals, hard plastics, etc. The rod-shaped formwork material 31 has a hook-shaped locking portion 31a formed on one end to make it easier to pull out the cable 10 from between the bent corner cushioning material 2. The locking portion 31a is not limited to the one formed by bending the end of the rod-shaped formwork material 31 into a hook shape, but may be a hole or groove formed on one end of the straight rod-shaped formwork material 31.

Each rod-shaped formwork member 31 is arranged in a cylindrical shape without gaps, with the locking portion 31a positioned on the opening side of the fixing pipe 13 and the length direction aligned with the axial direction of the cable 10. The number of rod-shaped formwork members 31 is as many as can cover the entire outer peripheral surface of the cable 10 without gaps, and is determined arbitrarily depending on the width of the rod-shaped formwork member 31 and the outer diameter of the cable 10. For example, when the diameter of the cable 10 is 140 mm or more, about 30 to 35 rod-shaped formwork members 31 with a width of 15 mm are used. The rod-shaped formwork members 31 in the embodiment have a flattened rectangular cross-sectional shape, but may also have a rectangular cross-sectional shape curved in an arc, or a polygonal or circular cross-sectional shape. In addition, rod-shaped formwork materials 31 with a cross-sectional shape that is flat or curved into an arc-like rectangle can be formed with a small thickness and a wide width, so compared to round rods with a circular cross-sectional shape, a small number of pieces can be used to cover the entire outer surface of the cable 10 without any gaps, given the fixed gap 5 between the cable 10 and the bent corner cushioning material 2.

As shown in FIG. 4, the covering formwork material 32 is a plate-like member with a semicircular cross section, and two of these are combined to form a cylindrical shape. The covering formwork material 32 is made of a hard material such as carbon steel or alloy steel (e.g., SUS304). The material of the covering formwork material 32 may be any material having a hardness equal to or greater than that of the cable 10, and may be other metals, hard plastics, etc. Each covering formwork material 32 is assembled so as to cover the entirety of the multiple rod-shaped formwork materials 31 arranged on the outer peripheral surface of the cable 10 from the outside and arranged in a cylindrical shape (see FIG. 2 (A)). The length of the covering formwork material 32 in the cable axial direction is formed shorter than the length of the rod-shaped formwork material 31 in the cable axial direction. The thickness of the covering formwork material 32 is formed thinner than the thickness of the rod-shaped formwork material 31. The covering formwork material 32 can smooth the uneven outer surface of the multiple rod-shaped formwork materials 31, so that the vibration and displacement of the cable 10 can be effectively transmitted to the corner-breaking buffer material 2. In addition, by arranging the covering formwork material 32 on the side of the corner-breaking buffer material 2, the corner-breaking buffer material 2 will not be damaged when the rod-shaped formwork material 31 is removed from between the cable 10 and the corner-breaking buffer material 2. The covering formwork material 32 is not limited to two semicircular plate-shaped members, but may be three to five arc-shaped plate-shaped members that are combined to form a cylindrical shape.

Next, the construction of the cable corner bend cushioning structure 1 (function variable construction method) will be described.
In the embodiment, the cable corner bend cushioning structure 1 can be constructed as a first cable corner bend cushioning structure 1A and a second cable corner bend cushioning structure 1B by installing or removing the rigid formwork material 3.

1. Construction of the First Cable Corner Bending Buffer Structure 1A As shown in FIG. 5(a1), first, a foamed plastic backup material 4 is inserted into the anchoring pipe 13 from its opening to a predetermined depth.

Then, a ring-shaped temporary assembly base 7 is attached to the outer peripheral surface of the cable 10 that is slightly protruding from the opening of the fixing pipe 13, and the rigid formwork material 3 is assembled on this temporary assembly base 7 (rigid formwork material temporary assembly process). The assembly of the rigid formwork material 3 on the temporary assembly base 7 is first performed by disposing a plurality of rod-shaped formwork materials 31 around the entire outer peripheral surface of the cable 10. At this time, the other end of each rod-shaped formwork material 31 that does not form the locking portion 31a is abutted against the upper surface of the temporary assembly base 7, and the length direction of each rod-shaped formwork material 31 is aligned in the axial direction of the cable 10 and arranged along the outer peripheral surface of the cable 10 so that there are no gaps around the entire circumference of the cable 10, forming a cylindrical shape. When disposing the rod-shaped formwork materials 31, a metal band may be wrapped around the outer periphery to hold each rod-shaped formwork material 31 in place so that it does not shift position. Once the arrangement of the multiple rod-shaped formwork members 31 is complete, two covering formwork members 32 are assembled into a cylindrical shape to cover the outer periphery of the multiple rod-shaped formwork members 31, completing the temporary assembly of the hard formwork members 3 on the temporary assembly base 7.

After the rigid formwork material 3 is provisionally assembled, the provisional assembly base 7 is removed from the cable 10, and as shown in FIG. 5(a2), the provisionally assembled rigid formwork material 3 is slid down along the cable 10 onto the backup material 4 in the anchoring pipe 13 and installed in the anchoring pipe 13 (rigid formwork material installation process).

After the rigid formwork material 3 is installed in the anchoring pipe 13, a blocking lid (not shown) with a filling port is installed at the opening of the anchoring pipe 13, and the liquid material of the corner-breaking buffer material 2 is filled into the anchoring pipe 13 from the filling port (corner-breaking buffer material installation process). When the material of the corner-breaking buffer material 2 hardens, as shown in FIG. 5 (a3), the blocking lid is removed, and the corner-breaking buffer material 2 is formed between the rigid formwork material 3 arranged on the outer circumferential surface of the cable 10 and the anchoring pipe 13. After the material of the corner-breaking buffer material 2 hardens, a metal band 8 (see FIG. 2 (A)) is tightened and fixed to the outer circumferential surfaces of the rod-shaped formwork material 31 and the covering formwork material 32 exposed from the opening of the anchoring pipe 13. This completes the construction of the first cable corner-breaking buffer structure 1A with the rigid formwork material 3 remaining between the cable 10 and the corner-breaking buffer material 2. In this embodiment, after the cable corner bend buffer structure 1A is installed, a disk-shaped cable hat 14 is attached to the cable 10 near the opening of the anchoring pipe 13 (see Figure 1).

2. Construction of the second cable corner break buffer structure 1B The second cable corner break buffer structure 1B is constructed by removing the rigid formwork material 3 of the first cable corner break buffer structure 1A. As shown in Fig. 6 (b1), (b2), and (b3), to remove the rigid formwork material 3, the cable hat 14 is removed, and the rod-shaped formwork material 31 and the covering formwork material 32 are removed in that order. When removing the rod-shaped formwork material 31, the locking portion 31a of the rod-shaped formwork material 31 is held and the rod-shaped formwork material 31 is pulled out from between the cable 10 and the corner break buffer material 2 (see Fig. 6 (b2)). By removing all the rod-shaped formwork materials 31, a space is formed around the cable 10, and the covering formwork material 32 is released from the corner break buffer material 2 by using this space, and is pulled out from between the cable 10 and the corner break buffer material 2 and removed (see Fig. 6 (b3)). By removing the rigid formwork material 3 in this manner, construction of the second cable corner bend cushioning structure 1B is completed, in which a gapped corner bend cushioning material 2 is formed with a ring-shaped gap 5 provided between the cable 10 and the corner bend cushioning material 2 (see Figure 6 (b4)).

As shown in FIG. 7, the second cable corner bend buffer structure 1B allows the cable 10 to be installed and operated with a cable vibration damping device 6. After the cable vibration damping device 6 is installed, a cable hat 14 may be installed on the cable 10 near the cable vibration damping device 6. The cable vibration damping device 6 has a configuration in which a vibration damping member 63 made of a viscoelastic rubber member, oil, or the like is interposed between a fixing pipe side fixing part 61 fixed to the outer peripheral surface of the opening of the fixing pipe 13 and a cable side fixing part 62 fixed to the outer peripheral surface of the cable 10. According to the cable vibration damping device 6, when cable vibration occurs in which the cable 10 vibrates spontaneously and periodically due to wind, rain, or the like, the cable vibration is transmitted to the vibration damping member 63 via the cable side fixing part 62, and the cable vibration can be attenuated by the resistance force of the vibration damping member 63. In other words, the gap-equipped corner bend buffer material 2 does not exert a restraining force against the cable vibration due to the gap 5, so that the cable vibration can be suppressed by the cable vibration damping device 6 without the corner bend buffer material 2 interfering.

After constructing the second cable corner-breaking buffer structure 1B, the rigid formwork material 3 can be reinstalled to form the first cable corner-breaking buffer structure 1A. When reinstalling the rigid formwork material 3, the removal order is reversed, that is, the covering formwork material 32 is first inserted into the gap 5 between the cable 10 and the corner-breaking buffer material 2, and then the rod-shaped formwork material 31 is installed between the cable 10 and the covering formwork material 32.

As described above, according to this embodiment, the rigid formwork material 3 is detachably arranged between the cable 10 and the corner-breaking buffer material 2, so that a first cable corner-breaking buffer structure 1A in which the rigid formwork material 3 remains and a second cable corner-breaking buffer structure 1B in which the rigid formwork material 3 has been removed can be constructed as needed.

For example, when the cable corner-breaking buffer structure 1 is first put into operation, the first cable corner-breaking buffer structure 1A is constructed with the rigid formwork material 3 remaining between the cable 10 and the corner-breaking buffer material 2. With this first cable corner-breaking buffer structure 1A, the displacement of the cable 10 acting on the anchoring point of the cable 10 is transmitted to the corner-breaking buffer material 2 via the rigid formwork material 3, suppressing the bending of the corners of the cable 10, and the cable vibration caused by the swaying of the cable 10 is transmitted to the corner-breaking buffer material 2 via the rigid formwork material 3, suppressing the vibration damping effect due to the material properties of the corner-breaking buffer material 2 itself.

After the first cable corner-breaking buffer structure 1A is put into operation, if observations show that the vibration damping effect of the material properties of the corner-breaking buffer material 2 itself is not enough to suppress the cable vibration due to the environment and traffic conditions at the actual bridge construction site, the function is changed to the second cable corner-breaking buffer structure 1B, in which the hard formwork material 3 is removed and replaced with the corner-breaking buffer material 2 with gaps. In this case, the cable vibration that could not be suppressed by the corner-breaking buffer material 2 can be suppressed by installing a cable vibration damping device 6 on the cable 10. In other words, the corner-breaking buffer material 2 with gaps does not exert a restraining force against the cable vibration due to its gaps 5, and does not interfere with the function of the cable vibration damping device 6, and on the other hand, when the cable 10 sways significantly and displacement occurs, the displacement of the cable 10 is transmitted to the corner-breaking buffer material 2 with gaps, suppressing the corner bending of the cable 10.

Therefore, according to this embodiment, the cable corner bend buffer structure 1 (1A, 1B) has the effect of suppressing the bending of the cable 10, while when a cable vibration damping device 6 is installed and used in combination with the cable 10, the function can be changed to a second cable corner bend buffer structure 1B that does not interfere with the function of the cable vibration damping device 6 by removing the hard formwork material 3 in the first cable corner bend buffer structure 1A.

In addition, the gapped corner bend cushioning material 2 in the second cable corner bend cushioning structure 1B contributes to extending the life of the cable vibration damping device 6 by suppressing overload on the cable vibration damping device 6 caused by excessive displacement of the cable 10, and can also function as a fail-safe after deterioration of the cable vibration damping device 6.

In addition, when the first cable corner bend buffer structure 1A is in operation, when the cable 10 is forcibly vibrated to inspect the condition of the cable 10, the rigid formwork material 3 can be removed to make way for the second cable corner bend buffer structure 1B. This allows the cable 10 to be inspected without being affected by the restraining force on the movement of the cable 10 caused by the corner bend buffer material 2, and the current performance condition of the cable 10 itself can be inspected correctly. After the inspection is completed, the rigid formwork material 3 can be reinstalled to return to the first cable corner bend buffer structure 1A.

The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims.
The rigid formwork material 3 is not limited to the one constituted by a plurality of rod-shaped formwork materials 31 and a plurality of covering formwork materials 32 as in the embodiment, but may be constituted by a plurality of members arranged in the circumferential direction of the cable 10 and forming a cylindrical shape along the outer circumferential surface of the cable 10. For example, it may be constituted by a plurality (about 2 to 5) of plate-shaped members whose cross-sectional shape is curved in an arc so as to be combined to form a cylindrical shape.
In addition, for the purpose of protecting the surfaces of the cables 10 and the bent corner cushioning material 2 and improving releasability from the hard formwork material 3, a protective material such as a thin film may be placed on the contact surfaces between the components.

1 Cable corner bend cushioning structure 1A First cable corner bend cushioning structure 1B Second cable corner bend cushioning structure 2 Corner bend cushioning material 3 Hard formwork material 4 Backup material 5 Gap 6 Cable vibration damping device 7 Temporary assembly base 8 Metal band 10 Cable 11 Bridge girder 12 Tower 13 Anchorage pipe 14 Cable hat 31 Rod-shaped formwork material 31a Locking portion 32 Covering formwork material 61 Anchorage pipe side fixing portion 62 Cable side fixing portion 63 Vibration damping member

Claims (5)

A rigid formwork material used for a cable corner-breaking buffer structure in which a corner-breaking buffer material is installed between the cable and an anchoring pipe surrounding the outer periphery of the cable at the anchoring portion of the cable stretched on a bridge,
A plurality of members are arranged in the circumferential direction of the cable to form a cylindrical shape along the outer circumferential surface of the cable, and the cable is detachably disposed between the cable and the corner-folding cushioning material,
This rigid formwork material for use in a cable corner-break cushioning structure is configured such that when it is left between the cable and the corner-break cushioning material, the displacement and vibration of the cable are transmitted to the corner-break cushioning material, and when it is removed from between the cable and the corner-break cushioning material, a corner-break cushioning material with a gap is formed, with an annular gap between the cable and the corner-break cushioning material. A plurality of rod-shaped formwork members each composed of a thin and long rod-shaped member, each of which is arranged in a line along the outer circumferential surface of the cable with its length aligned in the axial direction of the cable, over the entire circumference of the cable;
2. A rigid formwork material for use in the cable corner bend cushioning structure described in claim 1, comprising a plate-shaped member having an arcuate cross-section, and a plurality of covering formwork materials that cover from the outside a plurality of rod-shaped formwork materials arranged on the outer circumferential surface of the cable. The rigid formwork material used in the cable corner bend buffer structure according to claim 2, wherein each of the plurality of rod-shaped formwork materials has a locking portion at one end for pulling the rod-shaped formwork material out from between the cable and the corner bend buffer material and removing it. This is a construction method that makes it possible to change the function of a cable corner-breaking buffer structure in which a corner-breaking buffer material is installed between the cable and an anchoring pipe that surrounds the outer periphery of the cable at the anchoring portion of the cable stretched on a bridge,
A first cable corner-break cushioning structure is constructed in which the rigid formwork material according to claim 1 is disposed around the cable portion surrounded by the anchoring pipe so as to cover the entire outer circumference of the cable, a corner-break cushioning material is installed in the annular space between the rigid formwork material and the anchoring pipe, and the rigid formwork material is left between the cable and the corner-break cushioning material so that the displacement and vibration of the cable are transmitted to the corner-break cushioning material via the rigid formwork material,
A function variable construction method for a cable corner bend buffer structure, in which, when a cable vibration control device is installed and used in combination with a cable, the rigid formwork material in the first cable corner bend buffer structure is removed to form a corner bend buffer material with a gap provided with an annular gap between the cable and the corner bend buffer material, and a second cable corner bend buffer structure is constructed so as not to interfere with the function of the cable vibration control device. The hard formwork material comprises the rod-shaped formwork material according to claim 2 or 3 and a covered formwork material,
When constructing the first cable corner bend buffer structure, the rod-shaped formwork material is constructed in a state where one end side located on the opening side of the anchoring pipe is exposed from the covering formwork material,
5. The function variable construction method for a cable corner break cushioning structure according to claim 4, wherein when constructing the second cable corner break cushioning structure, when removing the rigid formwork material from between the cable and the corner break cushioning material, the rod-shaped formwork material is removed by holding and pulling out one end side of the rod-shaped formwork material, and then the covering formwork material is removed.

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