JPH08134835A - Cable vibration damper - Google Patents

Abstract

PURPOSE: To improve workability by jointly providing a vibration damper consisting of a viscoelastic body member and a vibration damper composed of a viscous fluid in the aerial height of a cable stretched between a structure and a main tower. CONSTITUTION: A cable 3 is stretched obliquely between a structure such as the stiffening girder of a cable stayed bridge and a main tower. A vibration damper A using a solid viscoelastic body member is installed on the base end side of the cable 3. A vibration damper C employing a viscous fluid is mounted to the cable 3 at a place upper than the vibration damper A. Accordingly, damping required for the vibration damper C is reduced due to the damping function of the vibration damper A, thus decreasing the mounting height of the vibration dampers A, C, then improving workability.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention attenuates vibrations generated in a cable obliquely stretched between a structure and a main tower, as in the case of a cable-stayed bridge, and is also used for a cable anchoring portion. The present invention relates to a cable damping device that can suppress changes in angle.

[0002]

2. Description of the Related Art As a cable damping device, (1) a damping device disclosed in Japanese Patent Application No. 3-274896 (2) a damper device disclosed in Japanese Patent Laid-Open No. 3-110207 (3) disclosed in Japanese Patent Laid-Open No. 3-96506 There is a vibration control device.

The damping device (1) is shown in FIG.
A cable 3 is diagonally stretched from the top of a main tower (not shown) to a stiffener girder K of the cable-stayed bridge. The fixing tube T whose lower end is fixed to the stiffening girder K is extended along the cable 3 to a height convenient for damping the cable 3, and near the free end of the fixing tube T, between the fixing tube T and the cable 3. Is provided with a vibration damping device A.

The vibration damping device A connects an inner flange F fixed to the cable 3 with a clamp P and an outer flange E welded to the fixing tube T with an annular viscoelastic body G in the direction of the cable 3. Is configured.

This vibration damping device is characterized in that almost only a shearing force is applied to the viscoelastic body G, and a damping function for damping the vibration of the cable and a spring for suppressing the angle change of the cable fixing portion. It also has functions.

The damper device (2) is shown in FIG. An outward flange 8 is provided on the outer circumference of the cable-stayed cable 3,
A cylinder 5 having an inward flange 6 on its outer circumference is connected to the casing pipe 4 with a bolt 10. A sealing material 14 is attached to the flange located at the outermost edge, and a viscoelastic substance 9 is filled in the gap between the flanges 6 and 8 to form a damper device A.

This damper device is characterized by applying a shearing force and a compressing / pulling force. The damping device (3) is shown in FIG. This is a vibration damping device C using a viscous fluid.

A member 10 indirectly fixed to the cable 3.
Is immersed in the viscous fluid L contained in the box 7 attached to the frame 5 fixed to the bridge girder G. Then, due to the vibration of the member 10 accompanying the vibration of the cable, shear deformation is given to the viscous fluid, so that a damping function is obtained.

[0009]

Although the conventional vibration damping device is constructed as described above, the amount of damping that can be added to the cable by mounting the device is from the cable fixing point to the vibration damping device mounting position. It is known that it is proportional to the distance, and if the required additional damping is large, the mounting position becomes high and the workability of mounting etc. deteriorates. Further, in such a case, there is a problem that the vibration damping device becomes conspicuous and the scenery is deteriorated. The present invention has been made in order to solve the above problems, and an object thereof is to obtain a vibration damping device which can improve workability and is also excellent in aesthetics.

[0010]

The cable damping device of the present invention is arranged at the height of the cable stretched between the structure and the main tower, and the vibration of the cable and the angle of the cable fixing portion are provided. A cable damping device that suppresses changes is characterized in that a damping device made of a viscoelastic body member and a damping device made of a viscous fluid are provided side by side.

[0011]

The cable damping device must have both a damping function of damping the vibration of the cable and a spring function of suppressing the change in the angle of the cable fixing section. Both of these functions depend on the deformation of the viscoelastic member. For the time being, it is satisfied.

However, since it becomes insufficient when a large amount of damping is added to the cable, a damping device using a viscous fluid is additionally provided to allow the cable to take a certain proportion of the required damping. To do so. Further, due to the damping function of the viscoelastic body member, the damping required by the viscous fluid damping device can be small, and the distance from the cable fixing point to the mounting position can be shortened. .

Therefore, the mounting height of the vibration damping device can be small. If the mounting height is reduced, workability in mounting can be expected to improve, and a vibration damping device with excellent workability can be provided.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an overall configuration diagram when an embodiment of the present invention is applied to a cable-stayed cable, and FIGS. 2 (a) and 2 (b) are different detailed configuration diagrams. In FIG. 1, A is a vibration damping device using a solid viscoelastic member provided on the proximal end side of the cable 3, and C is a viscous fluid connected to the cable 3 at a position above A above. It is a vibration control device.

In FIG. 2 (a), a vibration damping device A using a solid viscoelastic member is arranged in the same configuration as the conventional one shown in FIG. 4, and a vibration damping device C using a viscous fluid is This is a cylinder-piston type oil damper, which is constructed by connecting a pair of oil dampers, one end of which is pin-connected to a support member, to the cable 3.

Next, the vibration damping device C using viscous fluid in FIG. 2B has the same structure as that shown in FIG. 6 and is connected to the cable 3 in the same manner as in FIG. In addition, FIG.
In the modification of the first embodiment of FIG. 1, the vibration damping device C is replaced by the vibration damping device A.
It is explanatory drawing of 2nd Example provided below [of].

The vibration damping device C using the viscous fluid may be the viscous shear type damper shown in FIG. 6 in addition to the so-called oil damper of the cylinder-piston type as described above. Next, the present invention and the prior art are subjected to the structural specifications of the cable-stayed cable shown in Table 1 at a temperature of 0 ° C. to 50 ° C. and a vibration mode of 1st to 4th order. Table 1 shows the results of comparison of the mounting heights of the vibration damping devices under the condition that the above-mentioned characteristics are secured and the function of suppressing the angle change of the cable fixing portion is provided.

[0018]

[Table 1]

Here, the prior art 1 is only for the vibration damping device using the viscoelastic member, and the mounting height is 4.5 m. Prior art 2 is a vibration damping device using a viscous fluid, and the mounting height is 3.0 m. In this case, since it does not have a spring function of suppressing the angle change of the cable fixing portion, it was calculated assuming that a device having a spring function equivalent to the others was installed at a mounting height position of 0.7 m.

On the other hand, in the case of the first embodiment, the mounting height is within 1.5 m, and in the second embodiment, the mounting height is within 2.0 m, which is significantly higher than the conventional one. It's getting low.

Next, regarding the combination of the present invention and the prior art, under the structural specifications of the cable-stayed cable shown in Table 1, the result of studying the relationship between the mounting height and the maximum logarithmic decrement is shown. 7 shows.

Curve 1 is a vibration damping device A using a viscoelastic member.
Is a case where two sets are used by shifting the positions in the cable direction. A vibration damping device A'is provided on the proximal end side of the cable, and then a vibration damping device A is provided. In this case, device A '
Since the deformation of the device A is suppressed by the spring function of, the damping function is inferior to that of the device A alone.

Curve 2 is a vibration damping device C using a viscous fluid.
And a shock absorber B using an elastic body that suppresses an angle change of the cable fixing unit. In this case, since the deformation of the cable is suppressed by the spring effect of the device B,
The cable fixing point moves from the cable end to the vicinity of the device B mounting portion. Since the damping performance of the vibration damping device is proportional to the distance from the cable fixing point to the vibration damping device mounting position, the mounting position is higher than that of the device C alone.

The curve 3 shows the case where the vibration damping device A using the viscoelastic member of the present invention and the vibration damping device C using the viscous fluid are provided side by side. In this case, as described above, a damping device using a viscous fluid is additionally provided to allow the cable to have a certain proportion of the damping function required. Therefore, the damping function required for the vibration damping device using the viscous fluid can be small, and the distance from the cable fixing point to the mounting position can be shortened. Therefore, the mounting height of the vibration damping device can be small.

When two sets of the damping device C using the viscous fluid are used and the shock absorbing device B using the elastic body is also provided, the same function as the curve 3 can be obtained, but the device 3 is used. It makes the installation of the device impractical.

[0026]

As described above, the cable vibration damping device of the present invention has a small mounting height and can be expected to improve workability in mounting, is excellent in workability, and has excellent aesthetics. A shaking device is possible.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing the overall configuration of an embodiment of the present invention.

2A and 2B are explanatory views showing details of main parts of FIG. 1 which are different from each other.

FIG. 3 is an explanatory diagram showing the overall configuration of another embodiment of the present invention.

FIG. 4 is an explanatory diagram of a vibration damping device using a viscoelastic member.

FIG. 5 is an explanatory view of another vibration damping device using a viscoelastic member.

FIG. 6 is an explanatory diagram of a vibration damping device using a viscous fluid.

FIG. 7 is an explanatory diagram showing the relationship between the mounting height and the maximum logarithmic decrement of the combination of the present invention and the prior art.

[Explanation of symbols]

A ... a vibration damping device made of a viscoelastic body member, B ... a damping device using an elastic body, C ... a vibration damping device made of a viscous fluid.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Masafumi Ogasawara 2078-4-201 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture (78) Tetsuhiro Shimozato 2078-4-203 Totsuka-cho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture (72) ) Inventor Masazumi Okada 1-6-16 Shibakubo-cho, Tanashi City, Tokyo (72) Inventor Takuya Murakami 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Nihon Kokan Co., Ltd. (72) Inventor Katsuaki Takeda Tokyo 1-2 1-2 Marunouchi, Chiyoda-ku Nihon Steel Pipe Co., Ltd.

Claims (1)

[Claims] 1. A vibrating elastic body for a cable damping device, which is arranged at an aerial height of a cable stretched between a structure and a main tower to suppress vibration of the cable and angular change of a cable fixing portion, A cable damping device characterized in that a damping device made of a member and a damping device made of a viscous fluid are provided side by side.