JP3127191B2 - Cable damping device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention attenuates vibration generated in a cable which is obliquely stretched between a structure and a main tower, for example, as in the case of a cable-stayed bridge, The present invention relates to a cable damping device capable of suppressing an angle change.

There are 136,718 disclosed the vibration damping device (2) the damper device disclosed in JP-A-3-1110207 (3) the vibration damping device such as disclosed in JP-A-3-96506 - [0002] (1) JP-A-6.

FIG. 3 shows a vibration damping device (1).
A cable 3 is installed diagonally on the stiffening girder K of the cable-stayed bridge from the top of a main tower (not shown). 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 attenuation of the cable 3, and between the fixing tube T and the cable 3 near the free end of the fixing tube T. Is provided with a vibration damping device A.

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

[0005] This vibration damping device is characterized in that substantially only a shearing force acts on 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. Has both functions.

[0006] (2) of the damper device is shown in FIG. An outward flange 8 is provided on the outer periphery of the cable stayed cable 3,
A cylindrical body 5 having an inward flange 6 on its outer periphery is connected to the casing pipe 4 with bolts 10. Then, a seal member 14 is attached to the flange located at the outermost edge, and a gap between the flanges 6 and 8 is filled with a viscoelastic substance 9 to constitute a damper device A.

This damper device is characterized by applying a shearing force and a compressive / tensile force. FIG. 5 shows the vibration damping device (3). This is a vibration damping device C using a viscous fluid.

The member 10 indirectly fixed to the cable 3
Is immersed in a viscous fluid L contained in a box portion 7 attached to a gantry 5 fixed to a bridge girder G. The vibrating fluid is subjected to a shearing deformation by the vibration of the member 10 accompanying the cable vibration, so that the viscous fluid has a structure having a damping function.

[0009]

The conventional vibration damping device is constructed as described above, but the amount of attenuation that can be added to the cable by mounting the device is limited from the fixed point of the cable to the mounting position of the vibration damping device. Is known to be proportional to the distance, and when the required additional attenuation is large, the mounting position becomes high, and the workability of mounting and the like deteriorates. Further, in such a case, there is a problem that the vibration damping device is conspicuous, and the landscape is deteriorated. The present invention has been made in order to solve the above-described problems, and an object of the present invention is to obtain a vibration damping device that can improve workability and is also excellent in aesthetic appearance.

[0010]

A cable device according to the present invention is arranged near a cable stretched between a structure and a main tower to vibrate the cable and adjust the angle of a cable fixing portion. in suppressing the cable damping device changes, the viscoelastic body
First damping device made of material and second damping device made of viscous fluid
And the first vibration damping device is referred to as the second vibration damping device.
The cable is installed close to the cable fixing side .

[0011]

[Function] It is necessary for the cable damping device to have both a damping function for damping the vibration of the cable and a spring function for suppressing a change in the angle of the cable fixing portion, and both of these functions are performed by deformation of the viscoelastic member. For the time being is satisfied.

However, when a large attenuation is added to the cable, it is not sufficient. Therefore, by providing a vibration damping device using a viscous fluid, a certain ratio of the attenuation required for the cable is provided. To do. In addition, due to the damping function of the viscoelastic member, the damping required by the viscous fluid for the vibration damping device can be reduced, 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 small, workability in mounting can be expected to be improved, and a vibration damping device excellent in workability can be realized.

[0014]

FIG. 1 is a diagram showing the entire configuration in which an embodiment of the present invention is applied to a cable stayed cable, and FIGS. 2A and 2B are different detailed configuration diagrams. In FIG. 1, A is a vibration damping device using a solid viscoelastic member provided on the base end side of the cable 3, and C is a viscous fluid connected to the cable 3 at a position above the above A. 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. 3 , and in a vibration damping device C using a viscous fluid, Cylinder·
It is a piston type oil damper, and a pair of oil dampers, one end of which is pin-connected to a support member, is connected to the cable 3 by a pin.

Next, a vibration damping device C using a viscous fluid in FIG. 2B has the same configuration as that shown in FIG. 5 , and is connected to the cable 3 in the same manner as in FIG.

The vibration damping device C using the viscous fluid may be a viscous shear damper shown in FIG. 5 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 compared with each other at a temperature of 0 ° C. to 50 ° C. and in a vibration mode of 1st to 4th order under a structural specification of a cable stayed cable shown in Table 1 by using a logarithmic decrement of 0.02. Secure,
Table 1 shows the result of comparing the mounting height of the vibration damping device under the condition that the cable fixing portion has a function of suppressing an angle change.

[0018]

[Table 1]

Here, the prior art 1 is a case where only a vibration damping device using a viscoelastic member is used, and the mounting height is 4.5 m. Further, the prior art 2 is a case of a vibration damping device using a viscous fluid, and the mounting height is 3.0 m. In this case, the calculation was performed on the assumption that an apparatus having a spring function equivalent to that of the other apparatus was installed at a mounting height of 0.7 m since the apparatus did not have a spring function for suppressing a change in the angle of the cable fixing portion.

On the other hand, in the case of the first embodiment, the mounting height is within 1.5 m, and in the case of the second embodiment, the mounting height is within 2.0 m. It is lower.

Next, for the combination of the present invention and the prior art, the relationship between the installation height and the maximum logarithmic decrement of the cable-stayed cable under the structural specifications shown in Table 1 is shown . 6 is shown.

Curve 1 is a vibration damping device A using a viscoelastic member.
This is a case where two sets are used with their positions shifted in the cable direction. A damping device A 'is provided at the proximal end of the cable, and a damping device A is provided next to the damping device A'. In this case, the device A '
Since the deformation of the device A is suppressed by the spring function, the damping function is inferior to that of the device A alone.

Curve 2 represents a vibration damping device C using a viscous fluid.
This is a case where a buffer device B using an elastic body that suppresses a change in the angle of the cable fixing portion is combined. 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 mounting position of the vibration damping device, the mounting position is higher than that of the device C alone.

Curve 3 shows a case where a vibration damping device A using the viscoelastic member of the present invention and a vibration damping device C using a viscous fluid are provided side by side. In this case, as described above, by attaching a vibration damping device using a viscous fluid, a certain ratio of the damping function required for the cable is provided. 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 vibration damping devices C using a viscous fluid are used and a damping device B using an elastic body is provided, the same function as the curve 3 can be obtained. As a result, mounting the device becomes impractical.

[0026]

The cable vibration damping device of the present invention is as described above, and the mounting height is small, the workability in mounting can be expected to be improved, the workability is excellent, and the vibration control device is excellent in appearance. A vibration device becomes possible.

[Brief description of the drawings]

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

FIGS. 2 (a) and 2 (b) are explanatory diagrams showing details of different parts of FIG. 1 respectively.

FIG. 3 is an explanatory view of a vibration damping device using a viscoelastic member.

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

FIG. 5 is an explanatory view of a vibration damping device using a viscous fluid.

FIG. 6 shows the combination of the present invention and the prior art.
Explanatory drawing which shows the relationship between a mounting height and a maximum logarithmic decrement.

[Explanation of symbols]

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

Continued on the front page (72) Inventor Masafumi Ogasawara 2078-4-201, Totsukacho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture (72) Inventor Tetsuhiro Shimozato 2078-4-203, Totsukacho, Totsuka-ku, Yokohama-shi, Kanagawa Prefecture, Japan (203) Inventor Masami Okada 1-16-16 Shibakubo-cho, Tanashi-shi, Tokyo (72) Inventor Takuya Murakami 1-2-1, Marunouchi, Chiyoda-ku, Tokyo Inside Nippon Kokan Co., Ltd. (72) Katsuaki Takeda, Marunouchi, Chiyoda-ku, Tokyo No. 1-2, Nippon Kokan Co., Ltd. (56) References JP-A-5-59703 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) E01D 1/00 E01D 11/00

Claims (1)

(57) [Claims] 1. A vibration and suppress cable damping device the angular change of the cable fixing portion of the disposed near the tensioned cable the cable between the structure and the main column, a viscoelastic member Consisting of a first vibration damping device and a viscous fluid
A second vibration damping device, wherein the first vibration damping device is
A cable damping device, which is installed closer to a cable fixed side than a damping device.