JPH11350429A - Displacement restricting device of parallel cables - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent displacement of parallel cables from increasing over an expected value, and effectively suppress a breakdown of a damper member without obstructing the vibration control effect of a vibration control rubber damping device. SOLUTION: This displacement restricting device of parallel cables is provided with fixing metal fittings 3A, 3B fixed to the parallel cables 2A, 2B, a first arm body 5A pivotally supported on one fixing metal fitting 3A at a first pivotally supporting point P1 around the axis in the same direction as the lengthwise direction of the cable, and a second arm body 5B pivotally supported on the other fixing metal fitting 3B at a pivotally supporting point P2. The first and second arm bodies 5A, 5B are connected together through a joint means 6 so that the distance L between the first and second pivotally supporting points P1, P2 is made variable and the maximum distance Lm is regulated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in combination with a damping rubber damper device for suppressing the vibration of a parallel cable disposed between a main tower and a bridge girder of a cable-stayed bridge, for example, and the upper limit of the displacement between the cables. The present invention relates to a parallel cable displacement restraining device capable of preventing the damper member in the rubber damper device from being broken by restraining the damping member.

[0002]

2. Description of the Related Art FIG.
A cable a1 for tensioning a bridge girder b1 of a cable-stayed bridge as shown in (A), or a bridge girder b2 for a long span suspension bridge as shown in FIG. 5B is suspended from a main cable bridged between main towers. For the cable a2 for lowering and the like, a parallel cable in which a plurality of cables are arranged in a substantially parallel manner at intervals is adopted with the enlargement of the bridge.

[0003] In such a parallel cable, when the cable length exceeds, for example, 50 m, as shown in FIG. 6, the cable from the X direction connecting between the parallel cables c 1 and c 2 or an oblique direction close to the X direction. The wind may generate Karman vortices behind the cable c1 on the windward side, and the cable c2 on the leeward side may vibrate violently.

[0004] Conventionally, the vibration is caused by the Y direction perpendicular to the X direction.
Although the vibration in the direction of the direction has been regarded as a problem, the vibration in the X direction has also been observed depending on the wind direction and the wind speed. These vibrations have small structural damping of the cable itself, so if a slight periodic disturbance due to the wind continues, the vibrations will grow and become large amplitude, and there is a risk of breaking due to bending fatigue at the fixed part of the cable terminal. is there.

Therefore, as shown in FIG. 7, for example, various damping rubber dampers d using a high damping rubber material have been proposed. FIG. 1 shows a structure in which fixing members g1 and g2 fixed to the cables c1 and c2 are connected by a vibration damper i having a disk-shaped damper member i1 made of a high-damping rubber material. In this case, the deformation of the cable c in the X direction is directly the deformation of the damper member i1 in the X direction,
The deformation of the cable c in the Y direction is directly caused by the Y of the damper member i1.
Since the deformation occurs in the direction, the vibration damping effect can be exhibited in both the X and Y directions.

However, in the damping rubber damper device d, the shape and dimensions of the damper member i1 are generally set in consideration of the relative displacement of the cables c1 and c2. In such a case, there is a serious problem that the damper member i1 is broken.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a displacement restraining device for a parallel cable capable of restraining the displacement of the cable when the displacement of the cable increases more than expected and preventing the damper member in the rubber damper device from being broken. And

[0008]

In order to achieve the above object, a displacement restraining device for a parallel cable according to the present invention comprises: a fixing bracket fixed to each of the cables arranged in parallel at a distance; First pivotally supported at a first pivot point so as to be tiltable about an axis in the same direction as the length direction of the cable.
And a second arm which is pivotally supported at a second pivot point on the other fixture so as to be tiltable about an axis in the same direction as the length direction of the cable. , The second arm body is connected by a joining means that can change the distance between the first and second pivot points and regulates the maximum distance.

It is to be noted that the joint means is constituted by a groove portion which is provided in the longitudinal direction of the first arm member and which is closed at both ends, and a slide piece which is provided in the second arm member and which slides through the groove portion so as not to fall off. And the first arm body and the second arm body can be bent and connected to each other.
This is preferable so as not to impair the function of the damping rubber damper device.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an embodiment of a displacement restraining device for a parallel cable according to the present invention is used together with a damping rubber damper device to prevent the damper member in the damping rubber device from being broken. Will be described based on the drawings.

In FIG. 1, a displacement restraining device 1 for parallel cables according to the present embodiment (hereinafter referred to as "displacement restraining device 1").
Are fixing brackets 3A, 3B for fixing the two cables 2A, 2B, respectively, in this example, which are arranged substantially in parallel at intervals.
A first arm body 5A pivotally supported by one fixing bracket 3A at a first pivot point P1, and a second arm body 5B pivotally supported by a second fixing bracket 3B at a second pivot point P2. And the joining means 6 for connecting the first and second arm bodies 5A and 5B so that the distance L between the first and second pivot points P1 and P2 can be changed.

In the following, the cable 2 is used to generically refer to the cables 2A and 2B, the fixture 3 is used to generically refer to the fixing brackets 3A and 3B, and the arm 5 is used to refer to the first and second arm members 5A and 5B. And cable 2
Cables 2A, 2A in a plane perpendicular to the length direction Z
There is a case where a direction connecting between B is an X direction and a direction orthogonal to the X direction in the plane is a Y direction.

The vibration damping rubber damper device 20 includes a mounting bracket 21 for mounting to each cable 2,
1 and 21 are provided at a position close to the displacement restraint device 1.

In the present embodiment, the cable 2
It is a long body that hangs a bridge girder such as a cable-stayed bridge or suspension bridge as shown in (A) or (B) in tension, and is made of a rope with a twisted metal or fiber cord, or a single metal wire. Formed by wires.

In the present embodiment, the fixture 3 of the displacement restraint device 1 has a cylindrical main body 7 surrounding the cable 2.
The main body 7 is formed by divided pieces 7a, 7a that are divided into two along the length direction Z of the cable 2 to facilitate attachment and detachment. The divided pieces 7a, 7a are fixed to each other using bolts and the like, and tightened to form a cable 2a.
Firmly adhered to. Further, the main body 7 is provided with a mounting portion 8 which protrudes in the X direction from one of the divided pieces 7a toward the other cable 2.

In the present embodiment, the mounting portion 8 formed on one fixing bracket 3A is a pair of mounting pieces 9 parallel to each other.
A, 9A, and an outer end of the first arm body 5A can be tilted around an axis in the same direction as the length direction Z of the cable 2 by a support shaft 10A attached to the attachment piece 9A. It pivots at the first pivot point P1. In this example, the first arm body 5A is formed of a single plate-like body sandwiched between the mounting pieces 9A.

The mounting portion 8 formed on the other fixing bracket 3B is composed of a single mounting piece 9B, and the second arm 5B is supported by a support shaft 10B mounted on the mounting piece 9B.
Is pivotally supported at a second pivot point P2 so as to be tiltable about an axis in the same direction as the length direction Z of the cable 2. In this example, the second arm body 5B holds the mounting piece 9B.
The first arm body 5A and the mounting piece 9B have substantially the same thickness, and are arranged in parallel with each other.

Next, in the present embodiment, the joining means 6 comprises a first
Grooves 12 with both ends closed provided in the length direction of the arm body 5A
And a slide piece 13 provided on the second arm body 5B and slidably falling through the groove 12.

More specifically, in the present embodiment, the groove 12 is formed by an elongated hole formed in the first arm 5A and extending in the length direction of the arm 5A. Also slide piece 1
Numeral 3 is formed by a pin having a round shaft shape passing through the elongated hole in the Z direction, and both ends of the pin are connected to the arm 5B.
Are held by the plate-like bodies 11, 11.

Therefore, as shown in FIG. 2, the slide piece 13 can slide freely from the one end 12a to the other end 12b of the groove 12 so as not to fall off. The first and second pivot points P1, P1 The distance L between P2 can be freely changed, and the maximum of the distance L (maximum distance Lm) is regulated by the slide piece 13 abutting on the other end 12b.

In this embodiment, the connecting means 6 moves the first arm member 5A and the second arm member 5B in the Z direction by inserting the round shaft-shaped slide piece 13 through the elongated groove portion 12. Are connected so as to be able to be bent around the axis P3. Therefore, the displacement restricting device 1 can control the vibration of the cable 2 by using the vibration damping rubber damper device 20 even when the fluctuation occurs in a free direction combining the X direction and the Y direction when the fluctuation of the cable 2 is less than the maximum distance Lm. The fluctuation can be smoothly followed without obstructing the vibration effect.

When the fluctuation of the cable 2 reaches the maximum distance Lm, the first and second arm bodies 5A and 5B are in a stretched state, so that the fluctuation does not increase beyond the maximum distance Lm. The vibration damping device 20 is securely restrained and is prevented from being broken. The maximum distance Lm is set to be equal to or less than the safety limit of the rubber damper device 20.

Further, the vibration damping rubber damper device 20 is constituted by connecting the mounting brackets 21 with a vibration damper 22.
The mounting bracket 21 is a cable 2 similar to the fixing bracket 3.
Is formed in a cylindrical shape which surrounds and is fastened and fixed. Also damper 2
Reference numeral 2 includes a damper member 23 made of an attenuating rubber material, and connecting pieces 24, 24 having one end fixed to the damper member 23 and the other end fixed to each mounting bracket 21.

In the present embodiment, the damper member 23 has a columnar shape whose center line is oriented in the same direction as the length direction Z of the cable 2 and is disposed substantially at the center between the cables 2 and 2.
The damper member 23 is an elastic body formed of a highly damping rubber, and for example, has an internal loss (tan δ) of 0.1.
It is preferably set to 2 or more and 0.7 or less. Generally, the damping effect is determined by the internal loss (tan δ) of the damper member 23.
And the larger the value of the internal loss (tan δ), the more the vibration is absorbed. If the internal loss (tan δ) is less than 0.2, the vibration absorbing effect is small and the vibration damping effect tends to decrease. . Even if tan δ exceeds 0.7, the improvement of the damping effect cannot be expected much. More preferably, the value of the internal loss (tan δ) of the damper main part 6 is set in the range of 0.3 to 0.5. The value of the internal loss (tan δ) is a value measured with a viscoelastic spectrometer manufactured by Iwamoto Seisakusho under the conditions of a temperature of 70 ° C., an initial elongation of 10%, a dynamic strain of ± 1.0%, and a frequency of 10 Hz. .

In the vibration damping rubber damper device 20, the damper member 23 undergoes compressive / tensile deformation upon fluctuation (vibration) in the X direction and shear deformation upon fluctuation in the Y direction, and the internal loss (tan δ) of rubber at that time. Attenuates each vibration. The damper member 23 has a spring constant Kx in the X direction.
A through hole (not shown) penetrating in the Z direction in order to make the ratio Kx / Ky of the spring constant Ky in the Y direction close to 1.0.
May be formed one or more times.

Next, another example of the joining means 6 in the displacement restraining device 1 is shown in FIGS. In FIG. 3A, the first
5A is formed as a plate-like body having a substantially U-shaped cross section, thereby forming a groove portion 12 which is opened on one side surface and extends, and both ends of the groove portion 12 are closed by, for example, stopper pieces 14. I have. The slide piece 13 is provided in the groove 1.
2, a mounting portion 13 for fixing the second arm body 5B through the opening of the groove portion 12.
A protrudes. Therefore, the first and second arm members 5
A and 5B are connected so that the distance L can be changed. Since each of the arms 5A and 5B can be tilted around each of the pivot points P1 and P2, the arms 5A and 5B can follow variations in various directions to some extent. However, from the viewpoint of the vibration damping effect, the arms 5A and 5B can be bent as described above. Preferably, the second arm body 5B can be pivotally attached to the mounting portion 13A so as to be tiltable about an axis P3 in the Z direction, as shown in FIG. 3B.

In FIG. 4, a groove 12 having both ends open is formed in the first arm 5A, and the second arm 5B itself is slidably inserted into the groove 12 so that the distance L can be changed. doing. Further, a stopper piece 14 that protrudes from, for example, an edge of the second arm body 5B to restrict the maximum distance Lm by contacting the end of the groove 12 is provided. As described above, as the splicing means 6, those having various structures other than this example can be adopted.

[0028]

Since the parallel cable displacement restraining device of the present invention is constructed as described above, the displacement of the cable can be reliably prevented from increasing more than expected, and the vibration damping device in the rubber damper device is used. Destruction of the damper member can be effectively suppressed without impairing the effect.

[Brief description of the drawings]

FIG. 1 is a perspective view showing an embodiment of the present invention.

FIG. 2 is a sectional view thereof.

FIGS. 3A and 3B are partial perspective views showing another example of the joining means.

FIG. 4 is a partial perspective view showing still another example of the joining means.

FIGS. 5A and 5B are perspective views showing an example of a cable-stayed bridge and a suspension bridge in which a displacement constraint device for parallel cables is used.

FIG. 6 is a cross-sectional view illustrating vibration of the cable.

FIG. 7 is a perspective view showing an example of a damping rubber damper device.

[Explanation of symbols]

 2, 2A, 2B Cable 3, 3A, 3B Fixing bracket 5A First arm body 5B Second arm body 6 Joint means 12 Groove 13 Slide piece L Distance between pivot points Lm Maximum distance P1 First pivot point P2 2 pivot points

Claims (3)

[Claims] A first fixing point fixed to each of the cables arranged in parallel at a distance, and a first pivot point which can be tilted to one of the fixing pieces about an axis in the same direction as the length direction of the cable. A first arm body pivotally supported by a second arm body pivotally supported at a second pivot point on the other fixing bracket so as to be tiltable around an axis in the same direction as the length direction of the cable. Wherein the first and second arm members are connected by a joining means which can change the distance between the first and second pivot points and regulates the maximum distance. Restraint device. 2. The splicing means comprises a groove provided in the longitudinal direction of the first arm and having both ends closed, and a slide piece provided in the second arm and slidable through the groove. The parallel cable displacement restraining device according to claim 1, wherein: 3. The parallel cable displacement restraining device according to claim 1, wherein said splicing means connects the first arm body and the second arm body in a bendable manner.