JPH11200316A - Damping and supporting construction for bridge girder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a damping and supporting construction for a bridge girder definitely capable of absorbing vibration energy and preventing falling of bridge girder. SOLUTION: Ultra-high damping rubber body 44 fixed to the top surface of a bridge pier 12 has an ultra-high damping rubber 50 and a shear key 54 embedded in a coupling recessed portion 52A of an upper flange 52 fixed to the top of ultra-high damping rubber 50. The shear key 54 is housed almost in a contactless state in a housing recessed portion 56 of a sole plate 55 fixed to an auxiliary beam 22 of the bridge girder so as to give no load of the bridge girder acting to the ultra-high damping rubber body 44. If the bridge girder vibrates relative to the bridge piper 12 due to earthquake, the side surface 56A of a housing recessed portion 56 pushes the side surface 54A of the shear key 54. Since the load of bridge girder is not acting to the ultra-high damping rubber body 44, the ultra-high damping rubber 50 is sufficiently shear-deformed and vibration energy is absorbed and the falling of the bridge girder can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a support structure for a bridge girder, and more particularly, to a seismic control system for a bridge girder that reduces vibration even when there is a roll such as an earthquake to prevent the bridge girder from falling from a pier. Regarding the support structure.

[0002]

2. Description of the Related Art FIG. 11 shows a conventional structure for supporting a bridge girder on a pier.

In this support structure, a support 104 fixed on a pier 102 supports a bridge girder 106. The bearing 104 has a rubber 108 and a steel plate 110 laminated and vulcanized and bonded. With the bridge girder 106 supported, the bridge girder 1
The rubber 108 is compressed and deformed by the load of
Are compressed in the load direction (downward).

When a roll occurs due to an earthquake or the like, the bridge girder 106 vibrates in the direction of the swing (horizontal direction) with respect to the pier 102 due to the inertial force.
Undergoes shear deformation in the lateral direction and attempts to attenuate the vibration energy of this vibration.

As another supporting structure, there is a supporting structure using a bearing 114 as shown in FIG. This bearing 11
4 is composed of an upper shoe 116 and a lower shoe 118, and the upper shoe 116 is fixed to the bridge girder 106, and the lower shoe 118 is fixed to the pier 102, respectively. Also, the upper shoe 116 and the lower shoe 118
Are connected to each other by a rubber 120 so as to be movable in parallel and in the lateral direction.

[0006]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a damping support structure for a bridge girder which adds a damping effect by a damper made of ultra-high damping rubber, reliably absorbs vibration energy, and prevents the bridge girder from falling. As an issue.

[0007]

According to the first aspect of the present invention, a support erected on a pier to support a bridge girder, the load of the bridge girder does not act, and the bridge girder and the pier extend horizontally. An ultra-high damping rubber body interposed between the pier and the bridge girder so that a load acts upon relative movement.

[0008] The bridge girder is supported by a bearing installed on the pier, and the ultra-high damping rubber body is interposed between the pier and the bridge girder so that the vertical load of the bridge girder does not act. All loads are acting on the bearing.

[0009] When a roll occurs due to an earthquake or the like, the bridge girder moves in the direction of the swing (horizontal direction) with respect to the pier due to inertial force.
Vibrates. Due to this vibration, the bridge girder and the pier move relatively in the horizontal direction, and a load in the horizontal direction of the bridge girder acts on the ultra-high damping rubber body, so that the ultra-high damping rubber body is deformed. At this time,
Since the vertical load of the bridge girder is not applied to the ultra-high damping rubber body at all, the bridge girder is sufficiently deformed in the horizontal direction to absorb the vibration energy, and the bridge girder can be prevented from dropping from the pier.

[0010] In particular, the ultra-high damping rubber constituting the ultra-high damping rubber body has a loss factor (a stress acting on the ultra-high damping rubber, which is lower than that of a high damping rubber used for a normal seismic isolation structure, for example). When the phase difference of strain is δ, it is represented by tan (δ)), and the internal friction in the ultra-high damping rubber is large. That is, since much of the vibration energy is converted to heat energy, the vibration energy can be sufficiently absorbed.

When the bridge girder and the pier move relative to each other, the load of the bridge girder acts on the ultra-high damping rubber body. Therefore, not only when the bridge girder vibrates with respect to the pier, but also when the pier vibrates with respect to the bridge girder. In this case, vibration energy can be absorbed.

According to the second aspect of the present invention, a recess is formed in the bottom surface of the bridge girder, the ultra-high damping rubber body is fixed on the pier, and the upper part of the ultra-high damping rubber body is substantially in the recess. It is housed in a non-contact state.

Therefore, the invention described in claim 1 is specifically realized by the configuration described in claim 2.

That is, the upper part of the ultra-high damping rubber body fixed on the pier is accommodated in the recess formed on the bottom surface of the bridge girder, but the ultra-high damping rubber body and the recess are almost in a non-contact state. Has become. For this reason, the load of the bridge girder usually does not act on the ultra-high damping rubber body at all.

Further, when the bridge girder vibrates in the direction of shaking (horizontal direction) due to a roll such as an earthquake, the upper part of the ultra-high damping rubber body is accommodated in a recess formed on the bottom surface of the bridge girder. The upper part of the ultra-high damping rubber body is pressed against the side surface of the concave portion, and the load in the horizontal direction of the bridge girder acts on the ultra-high damping rubber body, and the ultra-high damping rubber body undergoes shear deformation.

The ultra-high damping rubber body may be formed entirely of ultra-high damping rubber. For example, the upper part of the bridge girder housed in the recess is made of a metal or a hard synthetic resin. The upper part made of hard synthetic resin and the lower part of the ultra-high damping rubber may be integrated.

As described above, the concave portion is formed on the bottom surface of the bridge girder,
With a simple structure in which the upper part of the ultra-high damping rubber body is simply accommodated in the recess in a substantially non-contact state, the vibration energy of the bridge girder due to the rolling such as an earthquake can be absorbed and the bridge girder can be prevented from dropping.

[0018]

1 and 2 show a first embodiment of the present invention.
A bridge 10 to which a bridge girder vibration control support structure according to the embodiment of the present invention is applied is shown.

The bridge 10 has a plurality of piers 12 erected from the ground. On the upper surface of the pier 12, a bearing 1
4 are fixed (four in this embodiment), and the bearing 14 supports the bridge girder 16. The bridge girder 16 is composed of a pair of main girder 18 arranged on the left and right in the width direction, and a horizontal girder 20 arranged between the main girder 18. An auxiliary beam 22 is arranged below the horizontal beam 20 so as to span the main beam 18.

As shown in FIG. 3, the bearing 14 has a substantially square upper and lower shoes 24 and 26, and the upper and lower shoes 24 and 26.
And an intermediate portion 28 in the shape of a trapezoidal trapezoidal side located between them.

A pair of protrusions 30 are provided on the left and right from the upper shoe 24, and a housing 32 is formed between the pair of protrusions 30. The lower part 2
Side ribs 34 erected upward from 6 are accommodated, and a predetermined interval is provided between the accommodating portion 32 and the side ribs 34. The relative movement between the upper shoe 24 and the lower shoe 26 is caused by the
The side ribs 34 contact the inner surface of the and are restricted to a predetermined range. Therefore, the amplitude of vibration of the bridge girder 16 supported by the bearing 14 with respect to the pier 12 is also limited to a predetermined range, and the amount of movement of the bearing is limited.

From the lower shoe 26, the mounting plate 3
6, an anchor bolt (not shown) projecting from the upper surface of the pier 12 is inserted into a mounting hole 38 formed in the mounting plate portion 36, and the bearing 14 is fixed to the pier 12. I have.

The center of the upper shoe 24 is reinforced with a thick portion 40 thicker than both ends, and a columnar engaging projection 42 projects upward from the center of the thick portion 40. Have been. When the bridge girder 16 is placed on the bearing 14 fixed to the pier 12, the engaging projection 42 engages with an engagement hole (not shown) formed on the bottom surface of the main girder 18, and the bearing of the bridge girder 16 is supported. 14 is limited in the horizontal direction.

On the upper surface of the pier 12,
An ultra-high attenuation rubber body 44 is fixed. As shown in FIGS. 4 and 5, the ultra-high attenuation rubber body 44 includes a central portion 46A formed into a cylindrical shape, and a flange 46B projecting outward from a lower edge of the central portion 46A. Base 4
6. A plurality of fixing holes 4 are formed in the flange 46B.
6C, and the pier 12 is inserted into the fixing hole 46C.
An ultra-high damping rubber body 44 is fixed to the pier 12 by inserting an anchor bolt (not shown) projecting from the upper surface of the pier 12. A plurality of substantially trapezoidal reinforcing ribs 46D are radially attached between the central portion 46A and the flange 46B,
The pedestal 46 is reinforced.

On the pedestal 46, a disk-shaped support plate 48 is placed and fixed, and on this support plate 48, a columnar ultra-high attenuation rubber 50 is fixed. Ultra high attenuation rubber 5
A disk-shaped upper flange 52 having the same diameter as the ultra-high-attenuation rubber 50 is fixed on the upper side. At the center of the upper surface of the upper flange 52, a joining recess 52A is formed.
The lower part of a cylindrical shear key 54 made of metal or hard synthetic resin is embedded and joined to A.

On the other hand, as shown in FIG. 4, a flat sole plate 55 made of metal is
7 fixed. On the bottom surface of the sole plate 55, a housing recess 56 having substantially the same diameter as the shear key 54 or a slightly larger diameter than the shear key 54 is formed.

When the ultra-high damping rubber body 44 is fixed to the upper surface of the pier 12 and the bridge girder 16 is placed on the bearing 14 on the pier 12, the shear key is inserted into the receiving recess 56 formed on the bottom surface of the sole plate 55. The top of 54 is housed. At this time, the housing recess 56 and the shear key 54 are substantially in a non-contact state to the extent that the vertical load of the bridge girder 16 does not act on the ultra-high damping rubber body 44. That is, the side surface 54A of the shear key 54 lightly contacts the side surface 56A of the housing recess 56, or an extremely small gap is formed between the side surface 54A of the shear key 54 and the side surface 56A of the housing recess 56. Further, between the upper surface of the shear key 54 and the bottom surface of the housing recess 56, and between the upper surface of the upper flange 52 and the sole plate 5.
There is also a predetermined gap between the bottom surface of 5 and the bottom surface. Therefore,
In a normal state, all loads of the bridge girder 16 act on the bearing 14 and do not act on the ultra-high damping rubber body 44.

On the other hand, the bridge girder 16 becomes the pier 12 due to an earthquake or the like.
6, the side surface 56A of the housing recess 56 presses the side surface 54A of the shear key 54, so that the shear key 54 receives a lateral (horizontal) force as shown in FIG. Thereby, the ultra-high damping rubber 50 undergoes shear deformation, and the shear key 54 and the upper flange 52
It is configured to move relative to the support plate 48 and the pedestal 46 in the horizontal direction.

Here, the ultra-high damping rubber 50 has a large loss coefficient as compared with a high damping rubber or the like used in a normal seismic isolation structure. The loss coefficient is represented by tan (δ), where δ is a phase shift difference between a stress acting on the rubber and a strain (deformation) generated in the rubber due to the stress, and the damping (internal friction) of the rubber Represents the size of Specifically, the loss coefficient of the high-damping rubber is (0.2 ≦ tan (δ) <0.4), while the ultra-high-damping rubber 50 has a loss coefficient of (0.4 ≦ tan (tan)).
(Δ) ≦ 0.8). For this reason, the ultra-high damping rubber 50
Is more likely to dissipate the energy of shear deformation as heat than high-damping rubber.

The ultra-high damping rubber 50 has a small rigidity (shear modulus) and a large shear strain with respect to shear stress, as compared with high damping rubber and the like. That is, when the same magnitude of shear stress acts on the high-damping rubber and the ultra-high-damping rubber 50, the ultra-high-damping rubber 50 is more likely to be sheared than the high-damping rubber.

Next, the operation of the vibration damping support structure for a bridge girder according to the present embodiment will be described. As shown in FIG. 1, in a normal state, the bridge girder 16 is supported by a bearing 14 fixed to the pier 12. As shown in FIG.
4 and a bottom surface of the housing recess 56, and between the upper surface of the upper flange 52 and the bottom surface of the sole plate 55, and the vertical load of the bridge girder 16 is extremely high damping rubber. The housing recess 56 and the shear key 54 are almost in a non-contact state so as not to act on the body 44. Therefore, the load of the bridge girder 16 acts only on the bearing 14, does not act on the ultra-high damping rubber body 44, and the ultra-high damping rubber 50 is not deformed at all in the vertical direction.

When the pier 12 rolls due to the earthquake, an inertial force acts on the bridge girder 16, so that the bridge girder 16 and the pier 12 tend to vibrate relatively in the horizontal direction. The upper shoe 24 of the bearing 14 also vibrates horizontally with respect to the lower shoe 26,
The bridge girder 16 vibrates in the horizontal direction with respect to the pier 12.

Since the side surface 56A of the recess 56 presses the side surface 54A of the shear key 54 due to the vibration of the bridge girder 16 against the pier 12, the shear key 54 exerts a horizontal force on the pedestal 46 as shown in FIG. As a result, the ultra-high damping rubber 50 undergoes shear deformation.

The ultra-high damping rubber 50 has a large loss coefficient as compared with the high damping rubber and the like, and much of the energy of shear deformation is dissipated as heat. Therefore, the pier 12 of the bridge girder 16
Is sufficiently absorbed by the ultra-high damping rubber 50 to prevent the bridge girder 16 from falling from the pier 12.

As described above, in the vibration damping support structure of the bridge girder according to the first embodiment, the ultra-high damping rubber body 44 is provided on the pier 12.
And the shear key 54 of the ultra-high damping rubber body 44 is inserted into the housing recess 5 formed in the sole plate 55 of the bridge girder 16.
6, the ultra-high damping rubber 50 can be sufficiently sheared and deformed to absorb the vibration energy of the earthquake and prevent the bridge girder 16 from falling.

FIGS. 7 to 9 show an ultra-high attenuation rubber body 64 according to a second embodiment of the present invention.

The ultra-high attenuation rubber body 64 also has the same pedestal 46, support plate 48 and ultra-high attenuation rubber 50 as the ultra-high attenuation rubber body 44 according to the first embodiment. The upper flange 52 is not fixed on the damping rubber 50, and instead, a cylindrical body 66 having a bottomed cylindrical shape and the same diameter as the ultra-high damping rubber 50 is fixed on the damping rubber 50. 44. Further, as shown in FIG. 7, the cylindrical body 6 is also provided on the sole plate 65 fixed to the auxiliary beam 22 with bolts 67.
A housing recess 68 having substantially the same diameter as 6 or slightly larger in diameter than the cylindrical body 66 is formed. A cylindrical body 66 is provided in the accommodation recess 68.
Is housed, and the housing recess 68 and the cylindrical body 66 are substantially in a non-contact state to the extent that the vertical load of the bridge girder 16 does not act on the ultra-high damping rubber body 64.

Therefore, even when the ultra-high damping rubber body 64 is used, the load of the bridge girder 16 (see FIG. 1) does not act on the ultra-high damping rubber body 64, and the ultra-high damping rubber 50 is compressed in the vertical direction. Not. For this reason, as shown in FIG. 9, when the bridge girder 16 vibrates in the horizontal direction with respect to the pier 12 due to the earthquake and the side surface 68A of the housing recess 68 hits the side surface 66A of the cylindrical body 66, the ultra-high damping rubber 50 Can be sufficiently sheared to absorb vibration energy.

Further, since the cylindrical body 66 is hollow, the weight of the ultra-high attenuation rubber body 64 can be reduced as a whole.

The ultra-high damping rubber members 44 and 46 are fixed upside down and fixed to the bottom surface of the auxiliary beam 22, and a plate is fixed to the upper surface of the bridge girder 12. The body 66 may be accommodated. Even in this case, in the normal state, the ultra-high attenuation rubber body 44,
If the load of the bridge girder 16 is not applied to the 64 ultra-high damping rubbers 50, the vibration of the bridge girder 16 due to the earthquake can sufficiently shear-deform the ultra-high damping rubbers 50 to absorb the vibration energy.

The support fixed on the pier 12 and supporting the bridge girder 16 is not limited to the support 14 described above.
For example, a bearing 74 shown in FIG. 10 may be used.

The bearing 74 has a columnar rubber 76 and a steel plate 78 laminated and vulcanized and bonded, and upper and lower shoes 82 and 82 having a diameter larger than that of the rubber 76 are bonded to the upper and lower ends. ing. The upper shoe 80 is fixed to the bottom surface of the main girder 18 (see FIG. 1), and the lower shoe 82 is fixed to the upper surface of the pier 12 (see FIG. 1) to support the bridge girder 16. In this state, the bearing 74 is compressed vertically by the load of the bridge girder 16. Further, unlike the bearings 14, those corresponding to the side ribs 34 and the projections 30 are not formed.

In a bridge using the bearing 74,
When the bridge girder 16 vibrates in the horizontal direction with respect to the pier 12 due to the earthquake, the ultra-high damping rubber body 44 fixed on the pier 12
Alternatively, since the ultra-high damping rubber 50 of the ultra-high damping rubber body 64 is sheared and absorbs vibration energy, the bridge girder 16 does not fall from the pier 12.

In the above description, the sole plates 55 and 65 are attached to the bottom surface of the auxiliary beam 22, and the sole plates 55 and 65 are provided with the housing recesses 56 in which the shear key 54 or the upper part of the cylindrical body 66 is housed. , 68 are formed, but the housing recesses 56, 68 may be formed on the bottom surface of the auxiliary beam 22 without mounting the sole plates 55, 65 on the bottom surface of the auxiliary beam 22.

[0045]

According to the present invention, the damper made of ultra-high damping rubber has a damping function, and the vibration energy can be reliably absorbed to prevent the bridge girder from falling.

[Brief description of the drawings]

FIG. 1 is a front view of a bridge to which a bridge girder vibration damping support structure according to a first embodiment of the present invention is applied.

FIG. 2 is a partially cutaway plan view of a bridge to which the bridge girder damping support structure according to the first embodiment of the present invention is applied.

FIG. 3 is a perspective view of a bearing used in a bridge girder vibration damping support structure according to the first embodiment of the present invention.

FIG. 4 is an enlarged cross-sectional view of the vicinity of an ultra-high damping rubber body of a bridge to which the bridge girder vibration damping support structure according to the first embodiment of the present invention is applied.

FIG. 5 is a perspective view of an ultra-high damping rubber body used for the vibration damping support structure of the bridge girder according to the first embodiment of the present invention.

FIG. 6 is an enlarged cross-sectional view of the vicinity of an ultra-high damping rubber body showing a state in which the bridge girder vibrates relative to the pier due to an earthquake in the seismic support structure for the bridge girder according to the first embodiment of the present invention.

FIG. 7 is an enlarged sectional view of the vicinity of an ultra-high damping rubber body of a bridge to which a bridge girder vibration damping support structure according to a second embodiment of the present invention is applied.

FIG. 8 is a perspective view of an ultra-high damping rubber body used in a vibration damping support structure of a bridge girder according to a second embodiment of the present invention.

FIG. 9 is an enlarged cross-sectional view of the vicinity of an ultra-high damping rubber body showing a state in which a bridge girder vibrates with respect to a pier due to an earthquake in a seismic damping support structure for a bridge girder according to a second embodiment of the present invention.

FIG. 10 is a cross-sectional view of another example different from that shown in FIG. 3 of a bearing used for the vibration damping support structure of the bridge girder according to the first embodiment of the present invention.

FIG. 11 is a front view of a conventional bridge.

FIG. 12 is a front view of a conventional bridge.

[Explanation of symbols]

 12 Bridge pier 14 Bearing 16 Bridge girder 44 Ultra-high attenuation rubber body 56 Housing recess (recess) 64 Ultra-high attenuation rubber body 68 Housing recess (recess) 74 Bearing

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Yasuo Imada 1-3-2-306 Inagekaigan, Mihama-ku, Chiba City, Chiba Prefecture -Raltown Ichibankan 203 (72) Inventor Chiaki Sudo 8-2-1004 Sakonyama, Asahi-ku, Yokohama-shi, Kanagawa

Claims (2)

[Claims] 1. A support erected on a pier to support a bridge girder; and a pier and a bridge girder such that a load is not applied to the bridge girder and a load is applied when the bridge girder and the pier relatively move in the horizontal direction. And an ultra-high damping rubber body interposed between the bridge girder and the seismic control structure of the bridge girder. 2. A recess is formed in a bottom surface of the bridge girder, the ultra-high damping rubber body is fixed on the pier, and an upper portion of the ultra-high damping rubber body is accommodated in the recess in a substantially non-contact state. The seismic damping support structure for a bridge girder according to claim 1, wherein: