JP2000160510A - Vibration reducing method for parallel bridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a realistic vibration reducing method for a parallel bridge capable of securely reducing the traffic vibration that becomes a problem in a plate girder bridge consisting of a plurality of plate girders in a wide frequency range without depending on the frequency characteristic. SOLUTION: This parallel bridge is made up of two high-level bridges 1, 2 bridged in parallel with each other. In the high-level bridges 1, 2, concrete floor boards F are placed on the widely used steel girders (I-girders) G. Then, the high-level bridges 1, 2 are mutually connected by a rubber damper 4. The rubber damper 4 is installed nearly in the central part of the web 5 in the height direction between the webs 5 of the steel girders G. In general, since the distance between the parallel bridges is slightly distant, the rubber damper 4 is installed on the webs 5 of the steel girders G via base plates 4 or the like. Thus, in the plan view, a prescribed gap is interposed in the axial direction of the bridge.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for reducing vibration of a parallel bridge, which reduces vibration caused by traffic load.

[0002]

2. Description of the Related Art Conventionally, in a sheet girder bridge composed of a plurality of sheet girders, noise and vibration are generated due to an impact caused by a joint of a traveling direction connecting portion and unevenness on a road surface. This noise can be mitigated to some extent by installing a sound absorbing material or a soundproof wall, but there is no effective means for reducing vibration. This traffic vibration not only gives the driver an uneasy feeling but also discomforts to the local residents and is a social problem. Such a problem is the same also in a parallel bridge constructed in parallel with each other.

Accordingly, various means have been developed and provided as means for suppressing traffic vibration.

As a typical example, a method of installing a pendulum type or a suspension type dynamic vibration absorber (Japanese Patent Publication No. 3-37057)
And the method of installing an active mass damper capable of controlling the vibration in a wide frequency band by arbitrarily changing the frequency (the invention described in JP-A-59-161566).

[0005]

However, the prior art has the following problems. With the method of installing a dynamic vibration absorber, general traffic vibration is random vibration with many frequency components overlapping, so a pendulum type dynamic vibration absorber that is effective only for a single frequency component was not suitable for this .

Further, in the method of installing the active mass damper, since the detection means and the control means are required, the apparatus itself is expensive, and it is necessary to operate the apparatus most of the time during use, so that frequent maintenance is performed. Needed. Therefore, it was not realistic.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems, and it is an object of the present invention to reliably reduce traffic vibration, which is a problem in a sheet girder bridge including a plurality of sheet girders, in a wide frequency band without depending on frequency characteristics. An object of the present invention is to provide a method for reducing vibration of a parallel bridge that is realistic.

[0008]

SUMMARY OF THE INVENTION The present invention has the following arrangement to solve the above-mentioned problems. The gist of the invention according to claim 1 is a method for reducing vibration of a parallel bridge in which two or more bridges are erected in parallel, wherein a bridge girder of the bridge is connected to a bridge girder of another bridge in parallel with a damper. The present invention resides in a method for reducing vibration of a parallel bridge. The gist of the invention according to claim 2 is a method for reducing vibration of a parallel bridge in which two or more bridges are erected in parallel, wherein a bridge girder of the bridge is connected to a bridge girder of another bridge in parallel with a damper. It exists in a parallel bridge characterized by being done.

Embodiments of the present invention will be described below in detail with reference to the drawings. As shown in FIG. 1, the parallel bridge according to the present embodiment includes two viaducts 1 and 2 that are bridged in parallel with each other. As the viaducts 1 and 2, a form in which a concrete floor slab F is mounted on a steel plate girder (I girder) G, which is often used, is illustrated.

The viaducts 1 and 2 are connected to each other by a rubber damper 3. The rubber damper 3 is a web 5 of sheet girder G
The web 5 is provided substantially at the center in the height direction of the web 5. Generally, since the distance between the parallel bridges is slightly apart, the rubber damper 3 is connected to the web 5 of the sheet girder G via the base plate 4 or the like.
It is installed in. In a plan view, as shown in FIG. 2, there is a predetermined interval in the bridge axis direction.

Next, the operation of the bridge will be described. When the vehicle travels on the floor slab F2, vertical vibrations occur on the sheet girder bridge due to unevenness on the floor slab F2 or an impact of a joint in the vehicle traveling direction. A traffic vibration occurs in each of the viaducts 1 and 2 on the parallel bridge. The traffic vibration is a random vibration in which many frequency components overlap, and the viaducts 1 and 2 on the left and right sides of the paper shown in FIG. 1 do not vibrate at the same amplitude and the same phase. As shown in FIG. 3, assuming that the vibration displacement on the left side is y1 (reference numeral 6 in the figure) and the displacement on the right side is y2 (7) at a certain moment, the relative displacement of the viaduct between them is y1-y2. As a result, a shear displacement of y1-y2 occurs in the shear rubber damper, and the vibration energy is dissipated as the shear deformation energy of the rubber damper, and the vibration of the sheet girder bridge is reduced.

Since the bridge according to the embodiment is configured as described above, the following effects can be obtained. Since the relative displacement between the left and right viaducts 1 and 2 dissipates energy as shear deformation of the rubber damper 3, vibration can be reliably reduced in a wide frequency band regardless of the frequency characteristics of traffic vibration.

Further, unlike the active control, there is no need for a detecting means, a control means, etc., and the apparatus itself is extremely inexpensive because the rubber damper 3 which is much cheaper than that is used.

Further, since the system is not an active system but a passive system, almost no maintenance is required.

Further, since the control is not the active control, the running cost can be reduced.

Further, not only the vibration due to the traffic load but also the vibration due to other live loads and the vibration due to the earthquake can be reduced.

In the present embodiment, the present invention is applied to a sheet girder bridge, but the present invention is not limited to this, and can be applied to a bridge having a girder structure suitable for applying the present invention.

As the damper, in addition to the rubber damper, a laminated rubber, an oil damper, another fluid damper, or a material suitable for practicing the present invention can be used. When an oil damper or the like is used, the oil damper or the like may be interposed between the left and right viaducts 1 and 2 using a bracket as shown in FIG. When an oil damper is used, energy is dissipated due to expansion and contraction displacement due to relative displacement y1-y2 between the two bridges.

Further, although the parallel bridge according to the above-described embodiment is composed of two viaducts 1 and 2, the present invention is not limited to this, and may be applied to a parallel bridge composed of three or more viaducts. Can be applied.

The number, position, shape, and the like of the above-mentioned constituent members are not limited to the above-described embodiment, but can be set to a number, position, shape, and the like suitable for carrying out the present invention.

It should be noted that a cable damping device for a cable-stayed bridge is particularly useful.
The invention described in Kaihei 10-195818 is disclosed
However, the invention of the present application is a simple diversion of the technology.
is not. The reasons are as follows. 1. Problem of installation position As shown in Fig. 5, in the case of cable a, half wavelength
Countermeasures are taken based on the vibration mode. JP-A-10-1
In a cable damper such as the technology disclosed in US Pat.
Cable vibration mode Install the damper at the position c where the vertical distance b is large.
In general, sufficient effects cannot be expected unless
You. Then, the distance e of the point c from the road surface d increases. Cable stay
In the case of a bridge, the number of cables is large, so
It takes days and cost to install par. Girder bridge
In this case, as shown in FIG.
The best position is the center h of the span. In the present invention, during the span
Even in the center, there is no problem with damper installation, where
It can be attached in the same way at the position.

2. Replacement frequency The material used for the shear type damper is changed in 5 to 10 years
It is common and replacement frequency is relatively high. Follow
The problem with the mounting position in 1. is that the number of replacements is large.
The more important it is in terms of maintenance.

3. Effectiveness against torsional vibration In the invention described in JP-A-10-195818, FIG.
As shown in the figure, the cable a is mainly
Vibration is suppressed by the shear deformation of the damper j
Is what you do. In the case of cables, the twist is generally
No vibration in the turning direction k occurs. In the case of a girder bridge, it is shown in FIG.
In addition to the vibration in the vertical direction i, the vibration in the torsional rotation direction k
Movement can also occur. The present invention produces a displacement in the torsional rotation direction.
Relative to the damper as in the case of vibration in the vertical direction i.
Therefore, torsional vibration can be suppressed.

4. Landscape and safety issues The clean beauty of the cable is one of the beauty of cable-stayed bridge
However, the invention disclosed in JP-A-10-195818
In order to attach the damper directly to the cable,
Impair. Also, the driver of the vehicle running on the bridge
Attention to the Le Damper creates no safety issues
You. The present invention is designed to be invisible to vehicles running on the road surface.
Because a damper is attached to the
No problem arises. Also, see the damper from around.
There is no problem with the landscape.

As described above, Japanese Patent Application Laid-Open No. 10-195818
Significant or unique effects not achieved by the invention described in the report
Therefore, the present invention is disclosed in Japanese Patent Application Laid-Open No. H10-195818.
It is not merely a diversion of the invention described in the publication.

In each of the drawings, the same components are denoted by the same reference numerals.

[0026]

Since the present invention is configured as described above, the following effects can be obtained. Energy is dissipated by the relative displacement of the bridge installed in parallel as the shear deformation of the rubber damper, so that the vibration can be reliably reduced in a wide frequency band regardless of the frequency characteristics of traffic vibration. Further, since the system is not an active system but a passive system, the apparatus itself is extremely inexpensive and requires almost no maintenance. Therefore, according to the present invention, it is possible to provide a realistic method for reducing vibration of a parallel bridge.

[Brief description of the drawings]

FIG. 1 is a front view of a bridge according to an embodiment of the present invention.

FIG. 2 is a plan view of the bridge shown in FIG.

FIG. 3 is a front view showing a relative displacement between two bridges shown in FIG. 1;

FIG. 4 is a front view showing a bridge according to another embodiment of the present invention.

FIG. 5 is a cable stay described in JP-A-10-195818.
It is a side view which shows a bridge.

FIG. 6 is a side view showing a parallel bridge according to the present invention.

FIG. 7 is a longitudinal sectional view of the cable shown in FIG. 5;

8 is a vertical cross-sectional view of the parallel bridge shown in FIG.

[Explanation of symbols]

 G Sheet girder F Floor slab 1 Left viaduct 2 Right viaduct 3 Shear type rubber damper 4 Base plate 5 Web 6 Left viaduct vibration displacement 7 Right viaduct vibration displacement 8 Relative displacement acting on rubber damper

Claims (2)

[Claims] 1. A vibration reduction method for a parallel bridge in which two or more bridges are erected in parallel, wherein a bridge girder of the bridge and a bridge girder of another bridge in parallel are connected by a damper. Vibration reduction method for parallel bridges. 2. A method for reducing vibration of a parallel bridge in which two or more bridges are erected in parallel, wherein a bridge girder of the bridge and a bridge girder of the other bridge in parallel are connected by a damper. Parallel bridge.