JPH11280024A - Seismic isolation device for structures - Google Patents

Abstract

(57) [Summary] [PROBLEMS] To provide a seismic isolation device capable of preventing generation of low-frequency vibrations in a bridge girder and preventing falling of the bridge girder from a pier. A seismic isolation member (11) arranged between a bridge girder (2) and a pier (3), and a bridge girder (2) arranged on four sides of the seismic isolation member (11)
Holding member 12 for holding the vehicle on the pier 3 side, and holding member 1
2, a sliding member 13 disposed between the lower flange portion 12c and the pier 3, a first connecting bolt 31 for connecting the upper flange portion 12b of the holding member 12 and the bridge girder 2, and a holding member 12
And the second connecting bolt 32 for connecting the lower flange portion 12c and the pier 3. The second connecting bolt 32 has a smaller horizontal breaking resistance than the first connecting bolt 31 and retains the pier 3. A movement restricting member 14 for setting a movable range of the member 12 within an allowable value is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a seismic isolation device for supporting a structure.

[0002]

2. Description of the Related Art Conventionally, as shown in FIG. 5, a seismic isolation device 53 is provided between a bridge girder 51 and a pier 52 of a highway to reduce the impact force generated during an earthquake.

The seismic isolation device 53 is composed of a seismic isolation member 61 in which a rubber plate and an iron plate are laminated, and bolts 62, 6 are provided on the bridge girder 51 side and the pier 52 side.
3 were connected.

Specifically, the upper mounting plate 6 of the seismic isolation member 61
1a is connected to the bridge girder 51 side by bolts 62, and the lower mounting plate portion 61b of the seismic isolation member 61 is connected to the bridge pier 52 side.

[0005] According to the seismic isolation device 53,
When a large horizontal impact force acts on the bridge girder 51, the impact force is reduced by the seismic isolation member 61.

[0006]

According to the structure of the conventional seismic isolation device, the bridge girder 51 is connected to the pier 5 via the seismic isolation member 61.
Because it is always fixedly supported on the two sides,
There is also a problem that the seismic isolation effect is exerted even in normal times, and therefore, low-frequency vibration is generated by the traffic of the vehicle. In addition, when the bolt 62 is broken and the bridge girder 51 is largely displaced, the bridge girder 51 is There was a danger of falling from 52.

Accordingly, an object of the present invention is to provide a seismic isolation device that can prevent the occurrence of low-frequency vibration in a structure and also prevent the structure from falling.

[0008]

In order to solve the above-mentioned problems, a seismic isolation device according to the present invention is a seismic isolation device disposed between a structure and a support, the structure and a support being provided. , A holding member arranged near the seismic isolation member to hold the structure on the support side, and a sliding member disposed between the lower surface of the holding member and the support body And a first connecting member for connecting the upper part of the holding member and the structure, and a second connecting member for connecting the lower part of the holding member and the support, and the second connecting member is more connected than the first connecting member. Along with setting the breaking force in the horizontal direction of the member to be small, a movement limiting member that sets the movable range of the holding member with respect to the support within an allowable value is provided, and the seismic isolation member in the above configuration is provided. Rubber plate and steel plate material are alternately laminated Than it is.

According to the above configuration, the structure is normally held on the supporting body side by the holding member arranged near the seismic isolation member during the normal time when no earthquake occurs. Is hardly exhibited, so that, for example, when the structure is a bridge girder, generation of low-frequency vibration by a passing vehicle is prevented.

On the other hand, when a large earthquake causes a very large horizontal force to act on the structure, the second connecting member having a low horizontal breaking resistance is broken, so that the seismic isolation member has The original function is exhibited. When the structure moves largely in the horizontal direction, the structure restricts the structure from falling off the support.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A seismic isolation device for a structure according to an embodiment of the present invention will be described below with reference to FIGS.

In this embodiment, a case where the present invention is applied to a bridge girder of a highway as a structure will be described. That is, as shown in FIGS. 1 to 3, the seismic isolation device 1 according to the present invention
Is arranged between the bridge girder 2 and the pier 3 when the bridge girder (structure) 2 of the highway is supported on the pier (support) 3 side.

The seismic isolation device 1 includes a seismic isolation member 11 disposed between the lower surface of the bridge girder 2 and the upper surface (top surface) of the pier 3, and four sides of the outer periphery of the seismic isolation member 11 (see FIG. 4). A holding member 12 disposed between the lower surface of the bridge 2 and the upper surface of the pier 3 to fix and hold the bridge girder 2 to the pier 3 side; and a sliding member 13 disposed between the holding member 12 and the pier 3. I have.

As the seismic isolation member 11, for example, a rubber plate 11a and a steel thin plate, that is, an iron plate 11b are alternately laminated. The holding member 12 is
A vertical portion 12a facing the seismic isolation member 11;
An upper flange portion 12b projecting from an upper end of the vertical portion 12a and a lower flange portion 12c projecting from a lower end of the vertical portion 12a.
And a reinforcing plate portion 12d disposed between the flange portions 12b and 12c.

The sliding member 13 is made of a steel plate placed on the pier 3 side and has a slippery coating layer (specifically, a tetrafluoroethylene resin film) F formed on the surface thereof. 21, and an adjustment plate (specifically, a plurality of thin shim plates) 22 disposed between the plate 21 and the lower flange portion 12 c of the holding member 12.

Each of the holding members 12 is connected to the bridge girder 2 and the pier 3 by bolts having different breaking strengths (horizontal shearing strength) in the horizontal direction.
That is, the upper flange portion 12b of the holding member 12 and the bridge girder 2
The side means a plurality of first connection bolts (first connection members) 31
The lower flange portion 12c of the holding member 12 and the bridge pier 3 side are connected to each other by a plurality of second connection bolts (second connection members) 32. The horizontal breaking force is 80% or less, preferably about 50%, of that of the first connecting bolt 31.

Further, the holding member 12 and the pier 3 side
A movement restricting member 14 is provided to restrict the range of movement of the holding member 12 and prevent the holding member 12 from dropping from the pier 3. The movement restricting member 14 includes a first cushioning member 41 supported so as to abut on a downward projecting portion 12 e of an end of the lower flange portion 12 c of the holding member 12, and a first cushioning member 41 fixed at a predetermined position on the upper surface of the pier 3. And two cushioning members 42, and the distance δ between the two cushioning members 41, 42 is set to be equal to or less than the allowable movement distance of the holding member 12 with respect to the pier 3.

The lower flange portion 12c of the holding member 12
The lower surfaces of the plate members 43 and 44 for preventing slippage for preventing the adjustment plate member 22 from being large in the event of an earthquake.
Are provided along the direction in which the cushioning members 41 and 42 are arranged.

In the above configuration, in a normal case where there is no earthquake, the bridge girder 2 is held on the pier 3 side by the holding members 12 arranged on all sides of the seismic isolation member 11, so that the seismic isolation member 11 Since the effect is hardly exhibited, generation of low-frequency vibration by the passing vehicle is prevented.

On the other hand, when a very large horizontal force acts on the bridge girder 2 due to the occurrence of a large earthquake, the second connecting bolt 32 having a low horizontal breaking resistance is broken. For this reason, the original function of the seismic isolation member 11 is exhibited, and the bridge girder 2
Large horizontal impact force from the wind is reduced.

At this time, if the bridge girder 2 moves in the horizontal direction and a large movement such as dropping from the pier 3 occurs, the abutment of the cushioning members 41 and 42 causes the pier 3 of the bridge girder 2 to abut. From falling off is prevented. In addition, the force in the vertical direction is partially reduced by the seismic isolation member 11.

In the above embodiment, the holding members are arranged in four directions according to the planar shape of the seismic isolation member. However, if the shape of the seismic isolation member is different, the number of the arranged holding members is increased or decreased accordingly. .

In the above embodiment, the seismic isolation device for supporting the bridge girder on the pier has been described. However, the present invention can be applied to the case of supporting a structure other than the bridge girder.

[0024]

As described above, according to the structure of the present invention, the structure is normally held on the support side by the holding member arranged near the seismic isolation member during normal times when no earthquake occurs.
Therefore, since the seismic isolation effect of the seismic isolation member is hardly exhibited, for example, when the structure is a bridge girder, the generation of low-frequency vibration by passing vehicles is prevented.

On the other hand, when a large earthquake causes a very large horizontal force to act on the structure, the second connecting member, which is set to have a low horizontal breaking strength, breaks, so that the original seismic isolation member cannot be used. Is exerted, and a large horizontal impact force from the structure is reduced. Further, when the structure is largely moved in the horizontal direction, the structure is prevented from dropping from the support by the slip prevention member.

[Brief description of the drawings]

FIG. 1 is a side view of a seismic isolation device according to an embodiment of the present invention.

FIG. 2 is a side view of a main part of the seismic isolation device.

FIG. 3 is a perspective view of a holding member in the seismic isolation device.

FIG. 4 is a schematic plan view of the seismic isolation device.

FIG. 5 is a side view when a conventional seismic isolation device is used.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Seismic isolation device 2 Bridge girder 3 Bridge pier 11 Seismic isolation member 11a Rubber plate 11b Iron plate 12 Holding member 12a Vertical portion 12b Upper flange portion 12c Lower flange portion 13 Sliding member 14 Movement restriction member 31 First connection bolt 32 Second connection bolt 41 1 cushioning material 42 second cushioning material

Claims (2)

[Claims] 1. A seismic isolation device disposed between a structure and a support, comprising: a seismic isolation member disposed between the structure and the support; and a seismic isolation device disposed near the seismic isolation member. A holding member for holding the structure on the support body side, a sliding member disposed between the lower surface of the holding member and the support, a first connection member for connecting the upper part of the holding member and the structure, A second connecting member for connecting the lower part of the holding member and the support, wherein the breaking force in the horizontal direction of the second connecting member is set smaller than that of the first connecting member, and the holding member for the support is A seismic isolation device for a structure, comprising a movement restricting member for setting a movable range of the vehicle within an allowable value. 2. The seismic isolation device for a structure according to claim 1, wherein the seismic isolation member is formed by alternately laminating rubber plates and steel plate materials.