JPH0860619A - Vibration-control damper for cable of diagonally stretched bridge - Google Patents

Abstract

PURPOSE: To obtain an excellent damping effect in a simple structure, by constituting the damper with a pair of flanges fixed at the cable side and the bridge girder side respectively, a cable side cylinder, a bridge girder side cylinder, and a viscous material charged in the bridge birder side cylinder. CONSTITUTION: A vibration-control damper is constituted of a damper 13, a pair of flanges 14, 15 fixed to the cable side 1 and the bridge girder side respectively and oppositely positioned, cable side cylinders 17a-17c fixed to the flange 14, bridge girder side cylinders 18a-18c fixed to the flange 15, and a viscous material 20. The cylinders 17a-17c vibrate in the axial direction by the vertical vibration of the cable 1 and the cylinders 17a, 17b inserted in independent chambers 19a, 19b receive the viscous shearing resistance due to the viscous material 20. When the cylinder 17a is moved in the axial direction, the inner and outer peripheral faces are moved relatively to the axial direction against the respective opposite faces thereof and at that time, a shearing force proportional to the relative transfer speed is generated in the viscous material 20 put between the opposite two faces and the shearing stress gives a resistance to the transfer faces and attenuates the vibration of the cylinder 17a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cable damping damper for a cable-stayed bridge, and more particularly to a cable damping damper for a cable-stayed bridge which has a simple structure and can achieve a high damping effect. is there.

[0002]

2. Description of the Related Art Generally, as shown in FIG. 4, a cable-stayed bridge has a structure in which a bridge girder b is hung from a tower T via a number of cables c. However, cable-stayed bridges in recent years have a long span and long cables. In addition, a large-diameter cable covered with polyethylene pipes has been adopted, and along with this, the vibration of the cable caused by wind, raindrops, etc. has become a problem.

Japanese Unexamined Patent Publication (Kokai) No. 3-96506 reports a damping device or damper for damping the cable. As shown in FIGS. 5 to 7, the damper a is installed on the bridge girder b so that the cable a and the cable c are crossed at right angles to the longitudinal direction of the cable c. The damper a is mainly composed of an upper structure d fixed to the cable c side and a lower structure e fixed to the bridge girder b side. The upper structure d has a resistance plate g welded and fixed to the lower surface of the lid plate f so as to be parallel to each other. These resistance plates g are partitioned by a box h of the lower structure e and a partition wall i. Separated room j
Inserted in each. The independent chamber j is filled with the viscous material k, and the resistance plate g is immersed in the viscous material k.
The vibration of the resistance plate g due to the vibration of the above is damped by utilizing the viscous shear resistance of the viscous body k. In particular, when the cable c is vibrating, the lower structure e is fixed because it is fixed on the bridge girder b side, so that the resistance plate g is separated from the independent chamber j.
There will be a relative motion within and that motion will be damped by the viscous body k.

The vibration of the cable c is mainly dominated by the vertical component. Therefore, a sufficient gap is provided below the resistance plate g so that a sufficient stroke amount can be secured. Further, it is the viscous shear resistance of the viscous body k existing between the opposing surface, that is, the inner wall of the box h and the partition wall i, that substantially damps the vibration of the resistance plate g. Since it is closely related to the space between them, it is necessary to accurately position the resistance plate g on the cover plate f and pay attention so that the resistance plate g and the inner wall of the box h and the partition wall i are in parallel and at constant intervals. is there.

Further, the vibration of the cable c has a small amount of other component in the vertical direction, that is, it vibrates three-dimensionally. Therefore, a gap is provided on the side of the resistance plate g to allow this. There is. That is, the resistance plate g is allowed to move three-dimensionally, and the movements in all directions are damped by the viscous body k.

[0006]

In the damper a, the upper structure d and the lower structure e are manufactured in advance, and these are assembled at the installation site. Here, when the upper structure d is manufactured, the resistance plate g
Must be positioned at right angles to the cover plate f, and must be accurately positioned so that the resistance plates g are completely parallel to each other. Since the resistance plate g is a flat plate having a certain length, There is a drawback that it is troublesome and time-consuming to manufacture.

During assembly at the installation site, the upper structure d and the lower structure e must be accurately combined or connected, that is, the plate surface of the resistance plate g of the upper structure d and this. The box h of the lower structure e and the wall surface of the partition wall i facing each other must be perfectly parallel to each other, and the gap distances around the entire circumference of the resistance plate g must be accurately set. In particular, as shown in FIG. 5, the upper structure d and the lower structure e have a rectangular cross section, and it is necessary to pay attention so that the long side direction thereof is perpendicular to the longitudinal direction of the cable c during assembly. is there. As described above, the damper a is directional, and assembly at the installation site is very troublesome.

Further, although the cable c vibrates three-dimensionally, a slight torsional vibration in the direction in which the resistance plate g rotates is generated, and the damper a effectively suppresses this torsional vibration. It is not possible. That is, in the damper a, it is effective only when the resistance plate g moves in the plate surface direction, and when moving in other directions, damping or damping effect cannot be expected so much.

Therefore, the present invention was devised in order to solve the above-mentioned problems, and an object thereof is a cable-stayed bridge which can be easily manufactured and installed and which can exhibit an excellent vibration damping effect with a simple structure. The purpose is to provide a damper for cable vibration control.

[0010]

In order to achieve the above object, the present invention provides a damper, which is interposed between a cable of a cable-stayed bridge and a bridge girder, for damping the cable. A pair of flanges fixed to the bridge girder side and arranged to face each other, a cable side tubular body fixed to the cable side flange and extended toward the bridge girder side flange, and fixed to the bridge girder side flange The bridge girder-side cylinder is inserted into the cable-side cylinder at a predetermined distance from the outside, and the viscous body is filled in the bridge-girder-side cylinder to allow the cable-side cylinder to be retracted.

[0011]

According to the above construction, the cable-side tubular body moves relative to the bridge girder-side tubular body with the vibration of the cable, and this movement is damped by the viscous shear resistance of the viscous body existing between the tubular bodies. . In particular, since the surface that generates the damping force is the surface along the circumferential direction of the tubular body, it is possible to effectively damp not only the vibration of the cable-side tubular body in the longitudinal direction but also the vibration in the rotational direction thereof. .

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

FIG. 1 shows a damper according to the present invention, and FIG. 2 shows its installed state.

First, referring to FIG. 2, a cable 1 obliquely stretched from a tower of a cable-stayed bridge penetrates a through portion 3 of a bridge girder 2 and a lower end thereof is fixed by an anchor 4 provided on a lower surface of the bridge girder 2. Part is supported. Further, a concrete base 5 is provided directly below the cable 1 in the vicinity of the through-hole 3 on the bridge girder 2. The base 5 and the cable 1 are laid vertically in the longitudinal direction of the cable 1 to provide a damper. 6 is installed.

As shown in FIG. 1, the damper 6 is a cable 1
Has a clamp part 7 for gripping the
Is a half body 8 that holds the cable 1 from above and below, and a flange body 10 fixed to the neck portion 9 of the lower half body 8 by welding or the like.
Mainly consists of and. The upper and lower halves 8 are bolts 1
1, the cable 1 is connected to each other while being gripped by a washer 1 and a nut 12.

A damper portion 13 is provided below the clamp portion 7, and the damper portion 13 has a pair of upper and lower flanges 14 and 15 fixed to the flange body 10 and the base 5, respectively, and arranged to face each other. . These flanges 14 and 15 have a plurality of holes 14a and 15 at equal intervals in the circumferential direction.
a is provided, a hole 10a is embedded in the flange body 10 and an embedding nut 5a is embedded in the base 5 in accordance with the positions of these holes. The upper flange 14 and the flange body 10 are coupled with each other by bolts 16 and nuts 17 which are inserted into the holes 14a and 10a, respectively.
The connection between the base 5 and the base 5 is performed by the bolt 16 and the embedded nut 5a described above. A washer is also used for these connections. Here, in particular, the flange body 10, the upper flange 14, and the lower flange 15 are exactly the same, that is, the parts are commonly used.

Further, on the lower surface of the upper flange 14, a plurality of cable-side cylinders 17a, 17b, 1 extending vertically and concentrically with the upper flange 14 and having different diameters are provided.
7c is fixed. Similarly, the lower flange 15
Also on the upper surface of the bridge, there are a plurality of bridge girder side cylinders 18a, 18b, 18c.
Is fixed. The cylindrical bodies 17a ..., 18a ... are alternately inserted at equal radial intervals, and conversely, are set to have such diameters. Further, after being inserted, between the cable side tubular body 17a and the lower flange 15, and between the bridge side tubular body 18a and the upper flange 14.
A gap of a predetermined distance is secured between the cable 1 and
A sufficient amount of stroke of the cable-side tubular body 17a due to the vertical vibration is secured. In particular, existing pipes such as gas pipes are adopted for these cylindrical bodies 17a, ..., 18a ..., These pipes are cut to a predetermined length and welded to the upper and lower flanges 14 and 15, respectively.

In this way, the independent chambers 19a and 19b are formed between the cylinders 18a and 18b on the lower flange 15 side, and between the cylinders 18b and 18c. A viscous body 20 made of a viscous oil such as silicone oil is filled to a predetermined height.
Further, as a result, the cylindrical bodies 17a and 17b respectively inserted into the independent chambers 19a and 19b are immersed in the viscous body 20 for a predetermined length (that is, area). In addition, as the viscous material 20, for example, a polymer viscous material such as polyisobutylene, polypropylene, polybutene, or asphalt can be used.

Of these cylindrical bodies 17a, ..., 18a ..., the cylindrical body 17c located at the outermost periphery on the side of the upper flange 14 is located.
Plays a role of a cover for preventing infiltration of rainwater and the like, and the viscous body 20 is not filled in the cylindrical body 18a located at the center of the lower flange 15 side.

A rubber 21 may be attached to the outer circumference of the cylindrical body 17c in order to prevent the intrusion of rainwater and the like.

Further, in FIG. 2, the damper 6 is mounted so that its axis is perpendicular to the cable 1, but the tower T
For cable 1 close to, cable 1 approaches vertical,
Therefore, the damper 6 approaches horizontal. Therefore, even though the viscous body 20 inside has a high viscosity, the surface thereof becomes horizontal after a long time, and there is a risk of overflowing from the lower side of the upper end of the cylindrical body 17c. Therefore, in this case, the mounting angle of the damper 6 to the cable 1 is not made to be a right angle, but as shown in FIG. 3, the damper 6 can be swung freely with respect to the cable 1 so that the damper 6 can be mounted close to the vertical. .

Next, the operation of the above embodiment will be described.

The vibration of the cable 1 is caused by wind or the like, and the particularly strong vibration force is the rain vibration generated in the strong wind accompanied by rainfall. Further, the cable 1 is also affected by a lateral wind or the like, and thus three-dimensionally vibrates due to a vibration component mainly in the vertical direction and a slight vibration component in the lateral and axial directions.

When the cable 1 vibrates, the vibration is transmitted to the cable side cylinders 17a ... Through the clamp portion 7. On the other hand, since the bridge girder side cylinders 18a ... Are fixed to the base 5 on the bridge girder 2, they are regarded as immovable, whereby the cable side cylinders 17a.

The vertical vibration of the cable 1 causes the cable side cylinders 17a to vibrate in its axial direction. At this time, the cylinders 17a and 17b inserted into the independent chambers 19a and 19b are viscous. Subjected to viscous shear resistance by 20. That is, for example, in the case of the cylindrical body 17a, the inner peripheral surface thereof is arranged on the outer peripheral surface of the cylindrical body 18a, and the outer peripheral surface thereof is arranged on the inner peripheral surface of the cylindrical body 18b at intervals. When the cylindrical body 17a moves in the axial direction, the inner and outer peripheral surfaces of the cylindrical body 17a move in the axial direction relative to the respective facing surfaces. At this time, a shear stress proportional to the relative moving speed is generated in the viscous body 20 sandwiched between the two opposed surfaces, and this shear stress gives a resistance force to the moving surface, whereby the vibration of the cylindrical body 17a is damped. Will be. A similar phenomenon occurs in the cylindrical body 17b, and the damper 6 reliably damps the vibration of the cable 1 by these.

In particular, the cable 1 also causes a slight amount of torsional vibration in the direction of rotating the cable side cylinders 17a. Also in this case, the surfaces acting on the damping are the inner and outer peripheral surfaces of the cable-side cylindrical bodies 17a and 17b and the respective facing surfaces,
That is, since the two surfaces are opposed to each other along the circumferential direction, viscous shear resistance in the reverse rotation direction is applied to the rotationally moving cylinders 17a and 17b, whereby torsional vibration can also be effectively suppressed.

Further, the damper 6 adopts a conventional installation method such as assembling after manufacturing, but at the time of manufacturing,
Fixing the upper flange 14 and the cable side cylinder 17a ...
Also, the lower flange 15 and the bridge girder side tubular body 18a ... Are fixed. The cylinders 17a ..., 18a ... are pipes such as gas pipes, which are cut, positioned and welded to the flanges 14 and 15. However, it is easy to cut the pipes at right angles to their longitudinal direction. However, if the cut pipe is positioned only at the center, a right angle with respect to the surfaces of the flanges 14 and 15 is naturally generated, and thus the positioning is very easy. That is, at the time of welding, in the case of the conventional example (see FIGS. 6 and 7), it is necessary to stand the resistance plate g on the cover plate f and support it at a right angle, whereas in the case of this embodiment, the flange 14, All you have to do is to put it on 15 and support it easily. In addition, in the case of the conventional example, the work of paralleling between the resistance plates g is also added, but in the case of this embodiment, if it is placed on the flanges 14 and 15, the parallelism is automatically generated, so that paralleling is not necessary. As described above, the damper 6 is easy to manufacture, and existing pipes such as gas pipes are used for the cylindrical bodies 17a ..., 18a ..., and the flange body 10 and the flanges 14 and 15 are made common. Therefore, it can be provided at an extremely low price. The structure is also very simple.

When the damper 6 is assembled, especially the damper portion 1
3 has no directivity with respect to the cable 1, that is, since it is cylindrical, the upper flange 14 can be freely rotated with respect to the flange body 10, and the lower flange 15 can be freely rotated with respect to the base 5. At this time, the flange 1
Since the holes 14a and 15a of the holes 4 and 15 are evenly spaced, holes at arbitrary positions can be used. As described above, the assembly and installation work of the damper 6 becomes very easy, and the rigidity of the flat plate can be improved by using the cylindrical body. Incidentally, the cylindrical body 1
In order to adjust the combination of 7a ..., 18a ... or the connection position, the holes provided in the flanges 14 and 15 may be elongated holes,
It is also possible to interpose an adjusting plate or the like between these flanges 14 and 15 and their counterparts.

As described above, such a damper has various advantages that it is very easy to manufacture, assemble, and install, it exhibits an excellent damping effect with a simple structure, and it can be provided at low cost. . Here, in the case of the present embodiment, in order to enhance the vibration damping effect, the cable side and the bridge girder side tube are provided with a multiple structure, but the minimum unit may be one each, that is, one cable side. It suffices if there is a tubular body and a bridge girder side tubular body inserted into the tubular body from the outside. Therefore, in the above embodiment, a combination of only the cylinders 17a and 18b or a combination of only the cylinders 17b and 18c is possible, and it is conceivable to omit the central bridge girder side cylinder 18a. In any case, the present invention can have various modes other than the above embodiment.

[0030]

The present invention exhibits the following excellent effects.

(1) Manufacture, assembly, and installation are very easy.

(2) A simple structure exerts excellent vibration damping effect.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional side view showing an embodiment of a cable damping damper according to the present invention when viewed from the longitudinal direction of a cable.

FIG. 2 is a side view showing an installed state of a damper.

FIG. 3 is a side view showing another installation state of the damper.

FIG. 4 is a side view showing a cable-stayed bridge.

FIG. 5 is a side view showing a conventional example and showing a damper installation state.

FIG. 6 is a plan cross-sectional view showing a conventional example of the damper as viewed from above, which is perpendicular to the cable longitudinal direction.

FIG. 7 is a side sectional view showing a conventional example when the damper is viewed from the cable longitudinal direction.

[Explanation of symbols]

 1 cable 2 bridge girder 14 upper flange 15 lower flange 17a, 17b, 17c cable side cylinder 18a, 18b, 18c bridge girder side cylinder 20 viscous body 21 rubber

Claims (2)

[Claims] 1. A damper, which is interposed between a cable of a cable-stayed bridge and a bridge girder to suppress the cable, and a pair of flanges fixed to the cable side and the bridge girder side and arranged to face each other. A cable-side tubular body fixed to the cable-side flange and extending toward the bridge girder-side flange, and a predetermined distance from the outside of the cable-side tubular body fixed to the bridge-girder-side flange. A cable damping damper for a cable-stayed bridge, comprising: a bridge girder side cylinder to be inserted and a viscous body filled in the bridge girder side cylinder and into which the cable side cylinder is immersed. 2. The cable damping damper for a cable-stayed bridge according to claim 1, wherein a plurality of the cable-side and bridge-girder-side tubular bodies are concentrically provided, and the tubular bodies are inserted alternately.