JP2001131914A - Seismic control supporting structure of bridge girder - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a seismic control supporting structure of a bridge girder, which surely absorbs vibration energy below and damps vibration even when great rolling or the like occurs. SOLUTION: A deformed portion 54 of a seismic control device 44 fixed to the upper face of a bridge pier 12 contains super damping rubber. The lower part of a shearing key 70 is embedded in and joined to a joint recess 68 formed in a connection steel plate 60. The upper part of the shearing key 70 is stored in a storage recess 76 of a sole plate 72 in the state of placing the bridge girder 16 on a support on the bridge pier 12 in such a manner that the storage recess 76 is put almost in non contact with the shearing key 70 without operation of vertical load on the seismic control device 44. When the bridge girder 16 is horizontally vibrated with respect to the bridge pier 12, the deformed portion 54 is subjected to sufficient sheating deformation to permit sufficient absorption of vibration energy of the bridge girder 16 on the bridge pier 12 and damping of the vibration.

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 support structure for a bridge girder that suppresses vibrations even when there is a roll such as an earthquake.

[0002]

2. Description of the Related Art As a conventional supporting structure for supporting a bridge girder on a supporting member, there is one shown in FIGS. 9A and 9B (see Japanese Patent Application Laid-Open No. 9-41321).

In this support structure 110, an existing bridge 112
A plurality of existing bearings between the existing pier 114 and the existing pier 114 are modified into a sliding bearing 116. Further, a seismic isolation device 118 is provided between the existing bridge 112 and the existing pier 114.

However, in this support structure 110, since the seismic isolation device 118 is a laminated rubber bearing with lead plugs or a high damping rubber bearing similar to those conventionally used for seismic isolation bridges, vibration inherent Although the period may be lengthened, the limit of the vibration energy absorption capacity is low. For this reason, when a large roll occurs, it is necessary to make the seismic isolation device 118 large in order to sufficiently absorb the vibration energy and attenuate the vibration.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in consideration of the above facts, and provides a vibration damping support structure for a bridge girder that can reliably absorb vibration energy and attenuate vibration even if a large roll occurs. As an issue.

[0006]

According to the first aspect of the present invention, a movable bearing is provided on a support member to support a bridge girder, at least one of which is capable of moving the bridge girder horizontally with respect to the support member. Provided so as to correspond to at least one of the movable bearings, and when a load of the bridge girder does not act and the bridge girder and the support member relatively move in the horizontal direction, the bridge girder is subjected to a shearing force to undergo a shear deformation. And a super damping rubber interposed between the support member and the bridge girder.

[0007] The "supporting member" referred to here may be any member that supports the bridge girder through a bearing, and includes, for example, general piers and abutments.

[0008] The bridge girder is supported by a bearing installed on such a support member. At least one of the bearings is a movable bearing, and the bridge girder is movable horizontally with respect to the support member.

When a roll occurs due to an earthquake or the like, the bridge girder vibrates in the horizontal direction relative to the support member due to inertial force. Due to this vibration, a load in the horizontal direction of the bridge girder acts on the super-dumping rubber, and the super-dumping rubber undergoes shear deformation. The “super damping rubber” of the present invention is, for example, compared with a high damping rubber or the like used for a normal seismic isolation structure, and has a loss coefficient (a phase difference between stress and strain acting on the ultra high damping rubber is δ. Sometimes tan
(Δ). ) Is large (specifically, 0.4 ≦
tan (δ) ≦ 0.8, preferably 0.5 ≦ tan
(Δ) ≦ 0.8), the internal friction in the ultra-high damping rubber is large. For this reason, much of the vibration energy is converted into heat energy by the shear deformation, and the vibration energy such as a large roll can be reliably absorbed and the vibration can be attenuated.

Further, in the present invention, since only the super damping rubber is provided corresponding to the movable bearing, the structure is not complicated. Furthermore, the present invention can be configured without making any change or improvement to the existing bridge girder support structure.

[0011] Since a horizontal load acts on the super-dumping rubber when the bridge girder and the support member move relative to each other, not only when the bridge girder vibrates with respect to the support member, but also when the support girder moves against the bridge girder. Vibration energy can be reliably absorbed.

According to a second aspect of the present invention, in the first aspect of the present invention, the super damping rubber is
The bridge girder is interposed between the support member and the bridge girder so that no vertical load acts on the bridge girder and only the shearing force due to the relative movement of the bridge girder and the support member in the horizontal direction acts thereon.

As described above, by preventing the vertical load of the bridge girder from acting on the super-dumping rubber at all, the super-dumping rubber is sufficiently sheared and deformed by the horizontal shear force, thereby effectively absorbing vibration energy. be able to.

In the above-mentioned invention, the super damping rubber may be provided corresponding to a part of the movable bearing.
As described in (1), by providing a structure corresponding to all the movable bearings, it becomes possible to more effectively absorb vibration energy.

[0015]

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 (or abutments) 12 erected from the ground. A fixed support 14 or a movable support 15 is fixed at a predetermined position on the upper surface of the pier 12, and these supports 14 and 15 support the bridge girder 16. In addition, the number of the fixed bearings 14 and the movable bearings 15 and the positions of the movable bearings 15 are determined in consideration of the overall configuration of the bridge 10, the location conditions, and the like, as in the related art. FIG. 1 shows the bridge 10 composed of only one bridge girder 16 for convenience of illustration, but a plurality of bridge girder 16 are arranged in the longitudinal direction,
The bridge 10 may be configured as a whole.

As shown in FIG. 2, 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 these main girder 18.

As shown in FIG. 3, the movable bearing 15 has an upper portion 24 and a lower portion 26 having a substantially rectangular shape, and an intermediate portion in the shape of a laterally equilateral trapezoid located between the upper portion 24 and the lower portion 26. 28. The intermediate portion 28 is made of an elastically deformable material, and the upper portion 24 and the lower portion 26 are relatively movable by deforming the intermediate portion 28.

From the upper shoe 24, a pair of projections 30 are provided on the left and right, respectively, and a housing 32 is formed between the pair of projections 30. In this accommodation part 32,
A side rib 34 standing upright from the lower shoe 26 is accommodated. There is a predetermined space between the housing portion 32 and the side rib 34, and the relative movement between the upper and lower shoes 24 and 26 is limited to a predetermined range by the side rib 34 hitting the inner surface of the housing portion 32. . 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.

From the lower shoe 26, the mounting plate 3 is directed sideways.
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 other hand, the fixed bearing 14 has an upper shoe and a lower shoe which are integrally connected to each other so as not to move relatively in the horizontal direction.

As shown in FIG. 4, a mounting plate 48 is fixed to the upper surface of the pier 12 to which the movable bearing 15 is fixed by an anchor bolt 46 at the center in a front view. The vibration damping device 44 is fixed.

The vibration damping device 44 includes a base plate 52 fixed to the mounting plate 48 by fixing bolts 50,
And a deformation part 54 attached to the second part 2.
As shown in detail in FIG. 5, the deforming portion 54 is formed by laminating a plate-shaped super damping rubber 56 and an internal steel plate 58 alternately in the thickness direction and fixing them by vulcanization bonding or the like. A connecting steel plate 60 having a thickness greater than that of the inner steel plate 58 is similarly fixed by vulcanization bonding or the like. Lower connecting steel plate 60
Is formed with a female screw (not shown). When the mounting bolt 62 is screwed into the female screw, the deformed portion 54 is attached to the base plate 52 as shown in FIG. . In addition, fixing recesses 66 are provided at corresponding positions (centers) on the opposing surfaces of the base plate 52 and the lower connecting steel plate 60.
The fixing key 64 is fitted in the fixing recess 66 without any gap. Thus, the displacement between the deformed portion 54 and the base plate 52 in the horizontal direction (the direction along the contact surface) is prevented.

In the state where the deformable portion 54 is fixed to the base plate 52, the deformable portion 54 is covered with a protective rubber 55 so as to be protected from the outside.

As can be seen from FIG. 5, a joint recess 68 is formed in the center of the upper surface of the upper connecting steel plate 60, and a cylindrical shear key made of metal or hard synthetic resin is formed in the joint recess 68. The lower part of 70 is embedded and joined.

On the other hand, a sole plate 72 made of metal and flat is fixed to the bottom surface of the cross beam 20 by bolts 74. A shear key 70 is provided on the bottom surface of the sole plate 72.
A receiving recess 76 having a diameter substantially the same as or slightly larger than the shear key 70 is formed.

The vibration control device 44 is fixed to the upper surface of the pier 12,
With the bridge girder 16 placed on the bearings 14 and 15 on the pier 12, the accommodation recess 7 formed on the bottom surface of the sole plate 72 is formed.
6, the upper part of the shear key 70 is accommodated. At this time,
The vertical load of the bridge girder 16 is all supported by the bearings 14 and 15, and this vertical load does not act on the vibration damping device 44, so that the housing recess 76 and the shear key 70 are almost in a non-contact state. That is, the outer peripheral surface of the shear key 70 may lightly contact the inner peripheral surface of the accommodation concave portion 76, or
There is a very slight gap between them. Further, the upper surface 70A of the shear key 70 and the lower surface 76A of the accommodation concave portion 76
, And between the upper surface 60A of the upper connecting steel plate 60 and the bottom surface 72A of the sole plate 72.

On the other hand, the bridge girder 16 becomes the pier 12 due to an earthquake or the like.
6, the inner peripheral surface of the housing recess 76 presses the outer peripheral surface of the shear key 70, and the shear key 70 receives a lateral (horizontal) force as shown in FIG. . As a result, the deformed portion 54 (particularly, a portion where the super damping rubber 56 and the internal steel plate 58 are laminated, see FIG. 5) is subjected to shear deformation.

Generally, the super damping rubber 56
Has a larger loss factor than high-damping rubber and the like used for ordinary seismic isolation structures. The loss coefficient is represented by tan (δ), where δ is a phase 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, for example, the loss coefficient of the high damping rubber is (0.2 ≦ ta
n (δ) <0.4, whereas in the super damping rubber 56, (0.4 ≦ tan (δ) ≦ 0.8, preferably 0.5 ≦ tan (δ) ≦ 0.8). is there. For this reason, in the super damping rubber 56, the energy of the shear deformation is easily dissipated as heat as compared with the high damping rubber or the like.

The super damping rubber 56 is
Compared with high-damping rubber and the like, the rigidity (shear modulus) is small and the shear strain with respect to shear stress is large. That is, when the same magnitude of shear stress acts on the high damping rubber and the super damping rubber 56, the super damping rubber 56 is more likely to be sheared than the high damping rubber.

Next, the operation of the damper 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 bearings 14 and 15 fixed to the pier 12. As shown in FIG. 4, predetermined gaps are formed between the upper surface 70A of the shear key 70 and the bottom surface 76A of the accommodation recess 76, and between the upper surface 60A of the upper connecting steel plate 60 and the bottom surface 72A of the sole plate 72. Yes, and
To the extent that the vertical load on the bridge girder 16 does not act on the vibration damping device 44, the sole plate 72 and the shear key 54 and the upper connecting steel plate 60 are almost in a non-contact state. Therefore,
The load of the bridge girder 16 acts only on the bearings 14 and 15, does not act on the vibration damping device 44,
Is not deformed at all in the vertical direction.

When the bridge pier 12 rolls due to an earthquake or the like, an inertial force acts on the bridge girder 16, so that the bridge girder 16 and the pier 12 tend to relatively vibrate in the horizontal direction. The upper shoes 24 of the bearings 14 and 15 also vibrate in the horizontal direction with respect to the lower shoes 26, and the bridge girder 16 vibrates in the horizontal direction with respect to the pier 12.

The vibration of the bridge girder 16 against the pier 12 causes the inner peripheral surface of the housing concave portion 76 to press the outer peripheral surface of the shear key 70. As shown in FIG. The deformation portion 54 (particularly, the portion where the super damping rubber 56 and the internal steel plate 58 are laminated) undergoes shear deformation. At this time, since the super damping rubber 56 is not deformed at all in the vertical direction, it is sufficiently sheared and deformed by the horizontal force. Further, since the super damping rubber 56 has a large loss coefficient as compared with a high damping rubber or the like, and much of the energy of shear deformation is dissipated as heat, the vibration energy of the bridge girder 16 against the pier 12 is It is sufficiently absorbed by the shear deformation and the vibration is attenuated. Since the amount of relative movement of the bridge girder 16 with respect to the pier 12 caused by the provision of the movable bearing 15 is reduced, collision of members constituting the movable bearing 15 and collision of adjacent bridge girder 16 can be reduced. Can be completely eliminated. Further, the bridge girder 16 can be prevented from falling from the pier 12.

The vibration damping device 4 corresponding to the movable bearing 15
4 that can move most of the vibration energy such as earthquakes.
As a result, the movable bearing 15 itself has elasticity in the horizontal direction, and the vibration energy acting on the fixed bearing 14 is reduced. That is, the vibration energy is distributed to the bearings 14 and 15, and the load on the fixed bearing 14 is reduced. In addition, since the load on the pier 12 on which the fixed bearings 14 are installed is reduced, the pier 12 can be effectively exhibited without impairing the cross-sectional performance of the pier 12.

As described above, in the vibration damping support structure of the bridge girder according to the first embodiment, the vibration damping device 44 is fixed on the pier 12, and the shear key 54 of the vibration damping device 44 is connected to the sole plate of the bridge girder 16. With a simple structure only to be accommodated in the accommodation concave portion 76 formed in the 72, the high damping function by the shear deformation of the super damping rubber 56 is sufficiently exhibited to absorb the vibration energy of the earthquake and prevent the bridge girder 16 from falling. be able to.

FIG. 7 shows a vibration damping device 8 of a bridge to which a bridge girder vibration damping support structure according to a second embodiment of the present invention is applied.
The vicinity of 4 is shown. In the second embodiment, only the structure of the vibration damping device 84 is different from that of the first embodiment. Therefore, the same structures, members, and the like are denoted by the same reference numerals, and description thereof is omitted.

In this vibration damping device 84, as shown in FIG. 8, a female screw 86 is formed at a predetermined position of the upper connecting steel plate 60 constituting the deformed portion 54, and the sole plate 72 is formed.
Is screwed into the female screw 86. As a result, the deformed portion 54 is connected to the sole plate 72 by the tension bolt 88,
All vertical loads of the bridge girder 16 are supported by the bearings 14 and 15 and do not act on the vibration control device 84.

In the second embodiment having such a configuration, similarly to the first embodiment, when the bridge girder 16 and the pier 12 relatively vibrate in the horizontal direction due to an earthquake or the like, Vibration energy is absorbed by the shear deformation of the deformation portion 54 of the vibration damping device 84, and the bridge girder 16 can be prevented from falling.

As described above, in the vibration damping support structure of the bridge girder according to the present invention, the load of the bridge girder 16 is prevented from acting on the vibration damping devices 44 and 84. , The high damping performance of the bridge girder 16 can be sufficiently absorbed, the energy of the relative vibration between the bridge girder 16 and the pier 12 can be reliably absorbed and the vibration can be suppressed.

Moreover, the vibration damping devices 44, 84 according to the present invention.
Can be installed without changing the structure of the existing bridge (support structure for supporting the bridge girder 16 on the pier 12), so that the cost does not increase. Of course, even when a bridge is newly constructed, the present invention can be configured by installing the vibration damping devices 44 and 84 corresponding to the movable bearing.

Further, super dumping rubber 56
Has a vibration damping function due to the high damping performance described above, so that it is not necessary to lengthen the natural period of the bridge and suppress the response to earthquake vibration (so-called seismic isolation). For this reason, even if the seismic isolation could not be performed due to a long natural period, such as a bridge installed on a soft base, etc.
The present invention can be applied to control the vibration.

In the above description, all the movable bearings 15
Although the case where the vibration damping devices 44 and 84 are installed corresponding to the above is described as an example, it is not necessary to install the vibration damping devices 44 and 84 corresponding to all the movable bearings 15. , 8
4 may be installed. From the viewpoint of more effectively absorbing the vibration energy of the relative vibration between the bridge girder 16 and the pier 12,
It is preferable to install the vibration control devices 44 and 84 corresponding to all the movable bearings 15. In addition, from the viewpoint of reducing the installation cost, the vibration damping device
It is preferable to install 4,84.

The cross section of the super-dumping rubber 56 is not particularly limited as long as the above-mentioned effects can be obtained.
To control the relative displacement between the bridge pier 12 and the bridge girder 16 to prevent damage due to collision between the ends of the bridge girder 16 and to adjust the load borne by each of the piers 12 to optimize the load on the cross section of the pier 12. It becomes possible.

The shape of the deformed portion 54 is not limited to the above-described square column (rectangular parallelepiped), but may be, for example, any other polygonal column or column.

[0047]

According to the first aspect of the present invention, there is provided a support which is provided on a support member to support a bridge girder, and at least one of which is a movable support capable of moving the bridge girder horizontally with respect to the support member. A support member and a bridge girder provided corresponding to at least one of the movable bearings, so that when the bridge girder and the support member move relative to each other in the horizontal direction without the load of the bridge girder being applied, the bridge girder is subjected to a shearing force and deformed by shearing. And a super-dumping rubber interposed between them, so that vibration energy such as large rolls can be reliably absorbed.

According to a second aspect of the present invention, in the first aspect of the present invention, the super-dumping rubber comprises:
Since the vertical load of the bridge girder does not act and is interposed between the support member and the bridge girder so that only the shearing force due to the relative movement of the bridge girder and the support member in the horizontal direction acts, the super damping rubber is used. Vibration energy can be effectively absorbed by sufficient shear deformation by the horizontal shear force.

According to the third aspect of the present invention, in the first or second aspect of the invention, since the super damping rubber is provided corresponding to all the movable bearings, vibration energy is further reduced. It becomes possible to absorb effectively.

[Brief description of the drawings]

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

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

FIG. 3 is a perspective view showing a movable bearing that constitutes a vibration damping support structure for a bridge girder according to the first embodiment of the present invention.

FIG. 4 is a front view showing the vicinity of a vibration damping device constituting the vibration damping support structure of the bridge girder according to the first embodiment of the present invention.

FIG. 5 is a perspective view showing a deformed portion of the vibration damping device according to the first embodiment of the present invention.

FIG. 6 is a front view of the vicinity of the vibration damping device, showing a state in which a roll has occurred in the vibration damping support structure of the bridge girder according to the first embodiment of the invention.

FIG. 7 is a front view showing the vicinity of a vibration damping device constituting a vibration damping support structure for a bridge girder according to a second embodiment of the present invention.

FIG. 8 is a perspective view showing a deformed portion of the vibration damping device according to the second embodiment of the present invention.

FIG. 9 is a schematic configuration diagram showing a conventional bridge girder support structure.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 Bridge 12 Bridge pier (support member) 14 Fixed bearing 15 Movable bearing 16 Bridge girder 44 Vibration control device 56 Super damping rubber 84 Vibration control device

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Toshiyuki Isobe 2-10-31 Misaki, Funabashi City, Chiba Prefecture (72) Inventor Renji Kiyota 1-1-401, Akitsu, Narashino City, Chiba Prefecture (72) Inventor Imada Yasuo 3-17-4-202 Chiharadai, Ichihara-shi, Chiba F term (reference) 2D059 AA05 AA33 AA37 GG01 GG12 GG59

Claims (3)

[Claims] 1. A bridge girder installed on a support member to support a bridge girder.
At least one is a movable bearing that allows the bridge girder to move horizontally with respect to the support member, and is provided corresponding to at least one of the movable bearings. A super damping rubber interposed between the support member and the bridge girder so that the support member and the bridge girder are subjected to a shearing force when the support member relatively moves in the horizontal direction, and a damping support structure for the bridge girder. 2. The super damping rubber is provided between the support member and the bridge girder so that the vertical load of the bridge girder does not act on the bridge girder and only the shearing force due to the relative movement of the bridge girder and the support member in the horizontal direction acts on the bridge girder. The seismic damping support structure of a bridge girder according to claim 1, wherein the bridge girder is interposed. 3. The vibration damping support structure for a bridge girder according to claim 1, wherein the super damping rubber is provided corresponding to all the movable bearings.