JPH0693604A - Damping of slant cable member in slantingly extended bridge - Google Patents

Abstract

PURPOSE:To prevent a forced vibration which is characteristic of a parallel cable type slantingly extended bridge, due to wind and simplify the structure thereof. CONSTITUTION:A damping device is composed of extended members 2, 2 connected to parallelly arranged slanting cable members 5, 5 and extended to both cable members 5, 5 facing to each other and a highly attenuating rubber 3 which is bonded at both ends to joint both extended members 2, 2 to decrease the relative transfer on relatively shifting to the axial direction between both extended members 2,2 as the result of vibration of the slanting cable 5 in the downstream side of wind. Since the high attenuating rubber 3 is deformed with a shearing force on relatively shifting between both extended members 2, 2, the vibration of the slanting cable member 5 is damped as soon as it is brought about. In particular, As a highly attenuating rubber 3 is used, the damping structure is simplified and not only the production cost is reduced but also at the same time the problem of appearance is solved and the necessity of maintenance is obviated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a damping device for a diagonal cable in a cable-stayed bridge, which damps wind vibrations of the diagonal cables installed in parallel.

[0002]

In a parallel cable type cable-stayed bridge in which a diagonal cable is installed in parallel between a main tower and a bridge girder, when the diagonal cable receives a lateral wind, it is leeward. In the diagonal cable on the side, forced vibrations are generated in the direction orthogonal to the wind direction and the axis of the diagonal cable due to the Karman vortices in opposite directions that are alternately generated on the back side of the diagonal cable on the windward side. It is necessary to take measures to reduce this vibration.

Conventionally, spacers are installed between parallel diagonal cables to connect them, and at the same time, diagonal cables parallel to each other in the height direction are connected to each other by wires to restrain the vibration of the diagonal cables. Alternatively, a damper is installed on the main tower or bridge girder at the end position of the diagonal cable to reduce the vibration by damping the vibration of the diagonal cable, but with the former method, the installation position of the spacer vibrates. This causes the sub-span vibration in the diagonal cable, and the wire intersects with the diagonal cable, which causes deterioration of the aesthetics of the cable-stayed bridge. The latter method usually requires maintenance because the damper uses a viscous damper or an oil damper, and in addition, the damper needs to be placed in the plane of vibration of the diagonal cable.
It is difficult to connect the diagonal cable to the main tower and bridge girder, and there are problems such as the cost for installation rising.

The present invention has been made in view of the actual situation of the conventional vibration reduction method, and is intended to newly propose a device which has a simple structure and effectively damps vibration.

[0005]

According to the present invention, at the same time as the sloping members facing each other are connected to the parallel diagonal cables, a high-damping rubber is installed between the sloping members to bond them to each other. When vibration of the material cable occurs, the two overhanging members are moved relative to each other to shear-deform the highly damped rubber and the vibration is damped by the highly damped rubber to simplify the structure for damping and reduce the manufacturing cost. While eliminating the problem of aesthetics and the need for maintenance, it also prevents the occurrence of subspan vibration.

The bulging member is connected to each diagonal cable and bulges toward the diagonal cable facing each other, and the high-damping rubber straddles between the two bulging members and is adhered to them so as to follow their relative movement. The high-damping rubber is bonded to both overhanging members to cause shear deformation at the time of relative movement in the axial direction between the two overhanging members due to the vibration of the diagonal cable on the leeward side, and this relative movement is damped, and the diagonal cable Dampen the vibration of.

The high-damping rubber damps the vibration of one of the diagonal cables on the leeward side, and therefore functions also when subspan vibration occurs when a spacer is installed between parallel diagonal cables.

Since the vibration damping device is composed only of the overhanging member and the high damping rubber, the structure is simplified and the manufacturing cost is reduced. Further, the vibration is damped by the high-damping rubber, which makes maintenance unnecessary, and the absence of the wires between the diagonal cables in the height direction prevents deterioration of aesthetics.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings showing an embodiment.

The damping device 1 of the present invention is a cable-stayed bridge in which diagonal cables 5 and 5 installed between a main tower and a bridge girder are arranged in parallel as shown in FIG. Overhang members 2, 2 connected to each of the diagonal cables 5, 5
And the high-damping rubber 3 bonded between the two overhanging members 2 and 2, and the wind of the diagonal cable 5 on the leeward side generated by the wind shown by the white arrow in FIG. Is a device that suppresses vibration in the direction orthogonal to the direction of the diagonal cable 5 and the direction of the diagonal cable 5.

As shown in FIG. 1, the projecting members 2 and 2 are connected to the diagonal cables 5 and 5 to oppose the diagonal cables 5 and 5, respectively.
It projects to the side of 5 and opposes each other so as to be relatively movable on the same axis. In the embodiment shown in FIG. 1, sleeves 4 and 4 which are fitted around the diagonal cables 5 and 5 in which the overhang members 2 and 2 are arranged in parallel.
Although it is connected to the diagonal cables 5 and 5 by being integrated with the above, the method of connecting the overhang members 2 and 2 to the diagonal cables 5 and 5 is arbitrary.

As shown in FIG. 3, the overhanging member 2 is inclined with respect to the normal state when one of the diagonal cables 5 vibrates, so that it can rotate with respect to the diagonal cable 5 within the range of the inclination. Connected. In the case of the embodiment shown in FIG. 1, sleeves 4, 4 are rotatably connected around diagonal cables 5, 5.

As shown in FIG. 2, which is a cross-sectional view of the diagonal cable 5 in FIG.
It is attached to both sides so as to follow the relative movement between the two.

FIG. 1 shows an embodiment in which the projecting members 2 and 2 are tubular. In this case, as shown in FIG. 2, one projecting member 2 extends to the other projecting member 2. inner tube 2 ₁ to be inserted is protruded within, high damping rubber 3 is bonded to both across between the inner circumferential surface of the outer peripheral surface and the other overhanging member 2 of the inner tube 2 _1.

FIG. 4 shows an embodiment in which the overhanging members 2 and 2 are plate-shaped. In this case, one overhanging member 2 continues to be plate-like and the other overhanging member 2 faces at least. The portion to be formed has a groove shape in which one of the overhanging members 2 is sandwiched, and the high damping rubber 3 is sandwiched between both of the overhanging members 2 and 2 and adhered to both. The two overhanging members 2 and 2 are combined in a shape overlapping with each other while facing each other so as to be movable relative to each other in the axial direction, and the high-damping rubber 3 is placed on the overlapping portion of the both overhanging members 2 and 2 as shown in FIG. It suffices that they are adhered to each other in such a state that they follow both of them when they move relative to each other and undergo shear deformation, and the shape of the overhang members 2 and 2 and the method of adhering the high damping rubber 3 corresponding thereto are not limited to the embodiment.

As shown in FIG. 3, the high-damping rubber 3 is stretched out when the diagonal cable 5 on the leeward side vibrates.
Of the overhanging members 2 and 2 by the hysteresis absorption energy that is retained by following both of them when they relatively move
The vibration of the diagonal cable 5 is damped by damping the relative movement between them and reducing the amplitude without restraining the vibration.

Since the vibration damping device 1 has a role of restraining a relative movement of a certain amount or more between the parallel diagonal cables 5 and 5 by connecting the overhanging members 2 and 2 with the high damping rubber 3, It is also used as a spacer for connecting the material cables 5 and 5. Further, since the damping effect of the high damping rubber 3 is higher as the shear deformation amount is larger, when the diagonal cables 5 and 5 are connected to each other by a spacer (not shown) in addition to the damping device 1, the damping device 1 It is installed at the position of the antinode of the vibration that maximizes the amplitude between the spacers, and at this time also suppresses the sub-span vibration that occurs between the spacers.

[0018]

The present invention is as described above, and is connected to each diagonal cable connected in parallel and extended to the opposite extending member side, and is adhered to both the extending members across both the extending members. Vibration of the diagonal cable because the high damping rubber is configured to be shear-deformed when the relative movement between the overhanging members is performed, and the relative movement between the overhanging members is attenuated by the shear deformation of the high-damping rubber. Can be suppressed at the same time as the occurrence.

In particular, the use of the high damping rubber simplifies the structure of the apparatus, reduces the manufacturing cost, eliminates the need for maintenance, and does not use the wire for connecting the diagonal cable in the height direction. Therefore, the beauty of the cable-stayed bridge is maintained.

Further, in order to damp the vibration of one of the diagonal cables on the leeward side by the high damping rubber, when a diagonal cable is connected by placing a spacer between the diagonal cables in parallel, subspan vibration is generated. Can also be suppressed.

[Brief description of drawings]

FIG. 1 is a perspective view showing an installation example of a vibration damping device.

2 is an axial cross-sectional view of the diagonal cable of FIG.

FIG. 3 is an axial cross-sectional view of the diagonal cable, showing how the diagonal cable on the leeward side vibrates.

FIG. 4 is a perspective view showing an example of bonding high damping rubber when the overhanging member has a plate shape.

FIG. 5 is a perspective view showing a cable-stayed bridge in which the present vibration damping device is used.

[Explanation of symbols]

1 ... Damping device, 2 ... Overhang member, 2 ₁ ... Inner tube, 3 ...
High damping rubber, 4 ... sleeve, 5 ... diagonal cable.

Claims (1)

[Claims] 1. A device which is installed between parallel diagonal cables, which is installed between a main tower and a bridge girder, and which suppresses vibration of the diagonal cables in the height direction due to wind. Connected to each other, the overhanging member that projects to the opposite diagonal cable side, and the two overhanging members that are adhered to each other and are bonded to each other along the axial direction between the two overhanging members accompanying the vibration of the diagonal cable on the leeward side. A damping device for a diagonal cable in a cable-stayed bridge composed of a high-damping rubber that shear-deforms during relative movement and attenuates the relative movement.