JP2002004217A - Vibration control structure of bridge girder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the collision of a bridge girder by a simple vibration control structure superior in attaching workability. SOLUTION: The bridge girders 1, 2 supported on a pier 3 and arranged at a prescribed interval 5 are connected through laminates 7, 8 comprising a steel plate and a rubber plate, and vibration damping effect is obtained by converting the vibration energy of the bridge girder into heat energy during the shearing deformation of the rubber plate.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vibration control structure for a bridge girder, and more particularly to a structure effective for suppressing vibration of a bridge girder of a bridge and preventing collision of the bridge girder.

[0002]

2. Description of the Related Art As a countermeasure against earthquakes, a rubber bearing material has been conventionally interposed between a pier and a bridge girder. Under such a measure, for example, adjacent bridge girder is in phase. When the horizontal vibration occurs in the above, the vibration can be effectively attenuated. By the way, adjacent bridge girders may vibrate in phase with each other due to an earthquake, but due to differences in the fixed form, weight, etc. between the bridge girders,
If there is a difference in the natural period, the two bridge girders will vibrate in different phases, there is a risk of collision between them, and there is a concern that the bridge girders may be damaged.

A conventional technique capable of attenuating relative vibrations due to such different phases is disclosed, for example, in Japanese Patent Application Laid-Open No. Hei 7-150517.
This is because rails are fixed to both end faces facing each other of the bridge girder arranged in a row with a predetermined clearance, and a pair of hooks are loosely fitted to each rail, and each hook is fixed to a fixing point via a damper. And further, by pivotally connecting the respective ends of the two intersecting connection bars to the hooks, the two end faces of the bridge girders are connected in series, and the relative displacement of the two bridge girders is It damps and suppresses under the action of the damper.

[0004]

However, this prior art has the drawback that the structure is complicated, the number of parts is large, and the production cost and labor are high. Therefore, the present invention provides a sufficient vibration damping function even when the relative displacement between adjacent bridge girders is large, and can sufficiently prevent collision between bridge girders.The structure is simple, small and inexpensive,
Moreover, the present invention provides a vibration damping structure for a bridge girder that can significantly reduce the number of manufacturing steps.

[0005]

In order to achieve the above object, the bridge girder damping structure of the present invention has the following configuration. That is, a bridge girder supported by a pier and connected to each other at predetermined intervals with a bridge girder through one or more vibration damping devices, wherein the vibration damping device vibrates due to shear deformation. And a viscoelastic body that attenuates the pressure.

According to this, the vibration can be efficiently attenuated by the large energy absorbing ability based on the large shear deformation of the viscoelastic elastic body, so that vibrations having different phases are generated in the bridge beams adjacent to each other. However, the collision of the bridge girder can be effectively prevented by sufficiently attenuating those vibrations. In this case, the vibration damping device can directly convert the vibration energy into the heat energy at the time of shear deformation of the viscoelastic body to attenuate the vibration, so that the vibration damping device is compared with the conventional technology using a damper having a mechanical structure. The vibration damping structure can be realized with a simple and small structure.

Incidentally, the vibration damping device can of course be constituted by a viscoelastic body, for example, a single rubber block. However, when it is constituted by a laminate of a rigid plate and a viscoelastic plate. Can appropriately adjust the amount of shear deformation under the action of the rigid plate.

[0008] In this case, the laminating direction of the laminated body is set to be substantially perpendicular to the bridge girder surface, so that the viscoelastic body undergoes only shear deformation with respect to approach and separation displacement between the bridge girders. Thus, the conversion of vibration energy to heat energy can be performed more efficiently.

When a vibration damping device comprising a laminate is attached, for example, when one laminate is used, one end of the laminate in the laminating direction is directly or indirectly fixed to one bridge girder, and the other end is fixed to It can be fixed directly or indirectly to the other bridge girder, so that an effective damping effect can be obtained.

In the case where separate laminated bodies are attached to both bridge girders, one end of each laminated body in the laminating direction is directly fixed to the bridge girders, and the other ends of the laminated bodies are connected to each other. Preferably, they are interconnected by arm members, whereby each laminate can be subjected to only shear deformation.

By the way, the material of the laminated body is, specifically,
By using a rigid plate as a steel plate and a viscoelastic plate as a rubber plate, high strength and a high vibration damping effect can be obtained. In this case, the loss coefficient of the rubber plate at −30 to 40 ° C.
When δ is 0.4 to 0.8, the vibration damping effect is further enhanced.
This loss coefficient is the same when a single block of rubber is used as the vibration damping device.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a longitudinal sectional view showing an embodiment in which two vibration damping devices are used. Here, the bridge girders 1 and 2 are mounted on the pier 3 via the respective bearing members 4 mainly made of rubber, and the bridge girders 1 and 2 are arranged at a predetermined interval 5 between their end faces. And arrange them. The illustrated vibration damping structure 6 includes two laminated bodies 7 and 8 as a vibration damping device to be described later, and a rigid arm member 9 connecting the laminated bodies 7 and 8. Are fixed to the lower surfaces of the thin end portions of the bridge girders 1 and 2 with bolts, shear bolts, shear keys, and the like. Is done.

Here, the laminated body 7 as a vibration damping device,
8, a plurality of internal steel plates 15 and a plurality of rubber plates 16 are alternately laminated between the connected steel plates 13 and 14 located at both ends in the laminating direction as shown in FIG. , Each rubber plate 16
Is integral with the peripheral rubber 17 surrounding the inner steel plate. The outer dimensions of the laminate 7 are, for example, 310 mm in length (A) and 460 mm in width (B).
And the height (C) can be 276 mm, and the thickness of each member can be 40 mm for the connecting steel plates 13 and 14, 3 mm for the internal steel plate 15, and 10 mm for the rubber plate 16. In addition,
The laminates 7 and 8 can be fixed to the bridge girder 1 and the like via the bolt holes 18.

When the bridge girders are relatively moved in the direction in which they are aligned under their attached state, as shown in FIG. 3, the laminates 7, 8 have a shear force acting on the laminates 7, 8. In the case where the shear deformation is caused in the horizontal direction by F, and such shear deformation is repeated in the positive and negative directions, the relationship between the amount of shear deformation and the amount of energy absorption is the size surrounded by the hysteresis loop shown in FIG. Thus, the absorbed vibration energy of the bridge girder is consumed mainly as heat energy, so that a large vibration damping effect can be obtained.

The vibration damping structure of the present invention may be provided on the side of the bridge girder as well as on the lower surface of the bridge girder as described above. The outer shape of the laminate is not limited to a rectangle, and various shapes such as an ellipse and a circle can be appropriately selected and used. In addition, the number and thickness of the steel plates and rubber plates to be laminated can be appropriately selected, and it is also possible to constitute one rubber plate. By the way, a method of manufacturing a laminated body is generally a method of laminating an unvulcanized rubber in the state of an unvulcanized rubber via an adhesive and then vulcanizing the laminated body, but is not limited thereto.

FIG. 5 shows a laminate as a vibration damping device.
It is sectional drawing which shows embodiment when only one is arrange | positioned between both ends girder. As shown in FIG. 5 (a), the upper and lower end faces of the laminated body 21 having sufficient energy absorption capacity and the like are directly fixed to alternately projecting thin portions of the bridge girders 1 and 2. FIG. 5 (b)
In FIG. 7, the lower end surface of the laminated body 21 having the upper end surface directly fixed to the thin end portion of one bridge girder 1 is connected to the other bridge girder 2 via the arm member 22. And FIG.
In the structure shown in (c), the respective upper and lower end faces of one laminate 21 are connected to the respective bridge girders 1 and 2 via the respective arm members 23 and 24. With any of these structures, the same operation and effect as in the above case can be obtained.

[0017]

As described above, according to the present invention, regardless of the difference in natural vibration between adjacent bridge girders, even when the relative displacement between bridge girders is large due to a large earthquake or the like,
It is possible to obtain a sufficient vibration damping effect such as avoiding collision between bridge girders. Further, when a laminate in which ultra-high damping rubber is laminated is used, energy absorption due to shear deformation is extremely high, and thus the vibration damping effect is higher.
Furthermore, the vibration damping device of the present invention has a simple structure, is easy to manufacture and install, and can easily cope with bridges under various conditions simply by adjusting the number of layers, the size of the device, the number of installations, and the like.

[Brief description of the drawings]

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

FIG. 2 is an enlarged view showing a laminate.

FIG. 3 is a side view illustrating a shear deformation state of the laminate.

FIG. 4 is a graph showing the energy absorbing ability of a laminate.

FIG. 5 is a longitudinal sectional view showing another embodiment.

[Explanation of symbols]

 1, 2 Bridge girder 3 Bridge pier 4 Bearing material 5 Interval 7, 8, 21 Laminated body 9, 22, 23, 24 Arm member 13, 14 Connecting steel plate 15 Internal steel plate 16 Rubber plate

Claims (7)

[Claims] 1. A damper structure for a bridge girder supported on a pier and interconnecting bridge girders arranged at a predetermined distance via one or more vibration damping devices, wherein the vibration damping device comprises: A bridge girder damping structure that includes a viscoelastic body that attenuates vibration due to shear deformation. 2. The vibration damping structure for a bridge girder according to claim 1, wherein said vibration damping device is constituted by a laminate of a rigid plate and a viscoelastic plate. 3. The vibration damping structure for a bridge girder according to claim 2, wherein the laminating direction of the laminate is substantially perpendicular to the surface of the bridge girder. 4. The laminated body has one end in the laminating direction,
4. The bridge girder damping structure according to claim 2, wherein the bridge girder is directly or indirectly fixed to one bridge girder, and the other end is directly or indirectly fixed to the other bridge girder. 5. The bridge girder according to claim 2, wherein one end of each of the laminations in the laminating direction is directly fixed to both bridge girders, and the other ends of the laminations are interconnected by arm members. Vibration control structure. 6. The vibration damping structure for a bridge girder according to claim 2, wherein the rigid plate constituting the laminate is a steel plate, and the viscoelastic plate is a rubber plate. 7. The vibration damping structure for a bridge girder according to claim 6, wherein a loss coefficient tan δ of the rubber plate at −30 to 40 ° C. is 0.4 to 0.8.