JP2005076195A - Base isolation bearing device for bridge, and bridge equipped with the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a base isolation bearing device which prevents excessive displacement of a bridge at the time of an earthquake that is likely to occur several times in its entire service life, thereby ensuring a bridge function, and exerts a base isolation function to prevent damage of the bridge at the time of a very strong earthquake. <P>SOLUTION: The base isolation bearing device 1 for the bridge is fixed to a bridge girder 3 via its upper surface 2 and to a pier 5 via its lower surface 4, respectively, and formed of a base isolation bearer 6 and a buckling mechanism 7. The base isolation bearer functions to bear the load of the bridge girder 3 in the vertical direction V and to seismically isolate the bridge girder 3 by displacement of the upper surface 2 with respect to the lower surface 4 in the horizontal direction H at the time of occurrence of vibrational displacement of the bridge girder 3 with respect to the pier 5 in the horizontal direction H. The buckling mechanism is arranged between the bridge girder 3 and the pier 5 so as to inhibit displacement of the upper surface 2 of the base isolation bearer 6 with respect to the lower surface 4 in a direction H1 orthogonal to a bridge axis when an external force F applied to the base isolation bearer 6 is at a predetermined value or below, and to buckle and allow the displacement of the upper surface 2 of the base isolation bearer 6 with respect to the lower surface 4 in the direction H1 orthogonal to the bridge axis when the external force F applied to the base isolation bearer 6 is in excess of the predetermined value. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a bridge-isolated bearing device and a bridge provided with such a bridge-isolated bearing device.

JP 2001-279952 A

  In seismic isolation devices for road bridges or railway bridges using seismic isolation bearings that do not have directionality such as laminated rubber bearings, the bridge axis is used for earthquakes that occur several times during the service life (for example, the maximum amplitude is 10 mm or less). Limiting members such as side blocks are provided on both sides of the seismic isolation bearing in the bridge width direction so that the bridge is not displaced more than necessary in the orthogonal direction (bridge width direction).

  By the way, when the displacement of the bridge more than necessary is limited by such a limiting member, the probability of occurring during the service life is very low, but the bridge may be damaged by an extremely strong earthquake (for example, the maximum amplitude of 10 mm or more). Yes, damage to bridges will cause enormous damage and will require a lot of time to recover.

  The present invention has been made in view of the above-mentioned points, and the object of the present invention is to prevent the bridge from being displaced more than necessary for an earthquake that occurs several times during the life of the bridge, thereby preventing the bridge from functioning. The object of the present invention is to provide a bridge-isolated bearing device for a bridge that can exhibit a seismic isolation function and prevent damage to the bridge in an extremely strong earthquake, and a bridge equipped with such a bridge-isolated bearing device.

  The seismic isolation bearing device for a bridge according to the first aspect of the present invention is designed to be fixed to the bridge girder on the upper surface and to the pier on the lower surface, and to support the vertical load of the bridge girder, while being horizontal to the bridge pier. The seismic isolation bearing that isolates the bridge girder by the horizontal displacement relative to the lower surface of the upper surface relative to the relative vibration displacement of the direction, and the external force added to this seismic isolation bearing that intersects the bridge axis If the external force in the direction of the bridge axis crossing that causes the displacement in the base isolation bearing is below a certain value, the displacement in the direction of the bridge axis crossing of the base isolation bearing is prohibited, while the external force applied to the base isolation bearing is prohibited. And a buckling mechanism arranged between the bridge girder and the bridge pier so as to allow the displacement in the crossing direction of the bridge axis of the seismic isolation bearing when it exceeds a certain value.

  According to the seismic isolation bearing device for a bridge of the first aspect, when the external force in the crossing direction of the bridge axis added to the seismic isolation bearing exceeds a certain value, the buckling mechanism buckles and the bridge axis crossing of the seismic isolation bearing concerned. Because the displacement in the direction is allowed, the seismic isolation function can be used for extremely strong earthquakes. As a result, bridge damage can be prevented and added to the seismic isolation bearing. When the external force in the crossing direction of the bridge axis is below a certain value, the buckling mechanism does not buckle and prohibits the displacement of the base isolation bearing in the crossing direction of the bridge axis. Can prevent the bridge girder from being displaced more than necessary and maintain the function of the bridge.

  In the seismic isolation bearing device for a bridge according to the second aspect of the present invention, the seismic isolation bearing is provided on a laminated rubber in which steel plates and elastic layers are alternately laminated, and on one end face in the laminating direction of the laminated rubber. And a bridge girder side mounting plate that is adapted to be attached to the bridge girder, and a bridge pier side mounting plate that is provided on the other end surface of the laminated rubber in the laminating direction and is adapted to be attached to the pier. The buckling mechanism has a pivotable member that faces the circumferential surface of the bridge girder side mounting plate or the bridge pier side mounting plate at the bridge axis crossing direction at one end and is rotatable relative to the pier or bridge girder at the other end. And a buckling member which is attached to one end of the rotatable member at one end and is fixed to the pier or bridge girder at the other end. When the external force is below a certain value, Blocking the movement and prohibiting shear deformation in the crossing direction of the laminated rubber via the bridge girder side mounting plate or pier side mounting plate, while the external force exceeds a certain value, buckles and turns The rotation of the laminated rubber is allowed, and the shear deformation of the laminated rubber in the crossing direction of the bridge axis is allowed.

  According to the seismic isolation bearing device for a bridge according to the second aspect, the rotation of the rotatable member is allowed by the buckling of the buckling member, and the shear deformation of the laminated rubber in the crossing direction of the bridge axis is allowed. As a result, the bridge can be prevented from being damaged only by buckling of the buckling member. As a result, the buckling member can be quickly recovered simply by replacing the buckled buckling member.

  The buckling member is fixed to one end of the rotatable member at one end and fixed to a bridge pier or a bridge girder at the other end as in the seismic isolation bearing device for a bridge according to the third aspect of the present invention. The bridge axis crossing added to the seismic isolation bearing may be provided by using one or a plurality of such plate-like bodies or by appropriately selecting the thickness thereof. The buckling mechanism can be buckled as desired in relation to the magnitude of the external force in the direction.

  As in the seismic isolation bearing device for a bridge according to the fourth aspect of the present invention, the buckling mechanism is configured such that the rotatable member is a bridge pier or a bridge girder so that the rotatable member is rotatable with respect to the pier or the bridge girder. The shaft member may be rotatably connected, and the rotatable member is rotatable with respect to the pier as in the seismic isolation bearing device for a bridge according to the fifth aspect of the present invention. The plastically deformable portion may be provided as much as possible, and the plastically deformable portion may include a constricted portion as in the seismic isolation bearing device for a bridge according to the sixth aspect of the present invention. .

  The seismic isolation bearing device for a bridge according to the seventh aspect of the present invention is adapted to be used for a bridge girder or a bridge pier having a surface orthogonal to the bridge axis crossing direction. The part faces the surface perpendicular to the bridge axis crossing direction of the bridge girder or pier, and the other end is attached to a rotatable member that can rotate with respect to the pier or bridge girder, and the other end is attached to the rotatable member. And a buckling member that is fixed to the pier or bridge girder at the other end, and the buckling member rotates the rotatable member when the external force is below a certain value. While blocking the movement and prohibiting the displacement in the crossing direction of the bridge axis of the seismic isolation bearing through the plane perpendicular to the crossing direction of the bridge girder or bridge pier, it will buckle if the external force exceeds a certain value. Allow the pivotable member to rotate and allow the displacement in the crossing direction of the bridge axis of the seismic isolation bearing It has become way.

  In the seismic isolation device for bridges of the seventh aspect, the buckling member is preferably fixed to one end of the rotatable member at one end, like the seismic isolation device for bridges of the eighth aspect of the present invention. And a plate-like body that is fixed to the pier or bridge girder at the other end, and the buckling mechanism is preferably a seismic isolation bearing device for a bridge according to the ninth aspect of the present invention. In order to make the rotatable member rotatable with respect to the bridge pier or the bridge girder, the shaft member that rotatably connects the rotatable member to the bridge pier or the bridge girder is provided. Preferably, as in the seismic isolation bearing device for a bridge according to the tenth aspect of the present invention, a plastically deformable portion is provided so as to be rotatable with respect to a pier or a bridge girder. Is preferably provided with a constricted portion like the seismic isolation bearing device for a bridge according to the eleventh aspect of the present invention.

  Even in the seismic isolation bearing device for bridges of the seventh to eleventh aspects, the seismic isolation bearing is formed by alternately laminating steel plates and elastic layers like the seismic isolation bearing device for bridges of the twelfth aspect of the present invention. Laminated rubber, a girder-side mounting plate provided on one end face in the laminating direction of the laminated rubber and adapted to be attached to the bridge girder, and provided on the other end face in the laminating direction of the laminated rubber. And a pier side mounting plate adapted to be attached to the pier, and the bridge girder is isolated by horizontal shear deformation of the laminated rubber against the horizontal relative vibration displacement of the bridge girder with respect to the pier. It may be like this.

  In the present invention, the seismic isolation bearing is preferably provided with at least one lead plug, as in the seismic isolation bearing device for bridges of the thirteenth aspect. Can be attenuated.

  The bridge of the present invention includes a bridge girder, a bridge pier, and the seismic isolation bearing device for a bridge according to any one of the above aspects. In this case, rails for railway may be laid on the bridge girder.

  According to the present invention, it is possible to prevent the bridge from being displaced more than necessary for an earthquake that occurs several times during the life of the bridge and maintain the function of the bridge. It is possible to provide a bridge having a base isolation device for bridges that can prevent damage and a bridge having such a base isolation device for bridges.

  Hereinafter, the present invention and preferred embodiments thereof will be described with reference to the drawings. In addition, this invention is not limited to these Examples at all.

  1 and 2, the seismic isolation device 1 for a bridge of this example is fixed to a bridge girder 3 on the upper surface 2 and to a bridge pier 5 on the lower surface 4 by bolts, anchor bolts, etc. An exemption for isolating the bridge girder 3 by supporting the load in the vertical direction V while isolating the bridge girder 3 by the horizontal H displacement relative to the lower surface 4 of the upper surface 2 with respect to the relative vibration displacement in the horizontal direction H relative to the pier 5 of the bridge girder 3 The seismic bearing 6 and the external force F applied to the seismic isolation bearing 6 and intersects the bridge axis, in this example, the bridge axis crossing direction orthogonal to the bridge axis and causing the displacement in the seismic isolation bearing 6, in this example When the external force F in the direction perpendicular to the bridge axis (bridge width direction) H1 is below a certain value, the relative displacement in the direction perpendicular to the bridge axis H1 with respect to the lower surface 4 of the upper surface 2 of the seismic isolation bearing 6 is prohibited. If the external force F applied to 6 exceeds a certain value, it buckles and is released It has and a buckling mechanism 7 arranged between the bridge beam 3 and the pier 5 to permit relative displacement of the bridge axis perpendicular H1 with respect to the lower surface 4 of the upper surface 2 of the bearing 6.

  The seismic isolation bearing 6 includes a laminated rubber 16 in which a pair of thick steel plates 11 and 12 and a plurality of thin steel plates 13 and a plurality of elastic layers 15 are alternately laminated, and a lamination rubber 16 in the lamination direction. The stacking direction of the laminated rubber 16 and the bridge rubber side mounting plate 18 provided on the exposed surface 17 of the thick steel plate 11 as one end face and attached to the bridge girder 3 on the upper surface 2 via bolts or the like. A pier side mounting plate 20 which is provided on the exposed surface 19 of the thick steel plate 12 which is the other end surface of the pier and which is attached to the pier 5 via an anchor bolt or the like on the lower surface 4, The shear key 21 is fitted to the steel plate 11 and is fitted to the bridge girder side mounting plate 18 on the other side, and is fitted to the thick steel plate 12 on the one hand and is fitted to the pier side mounting plate 20 on the other side. The shearing key 22 It is provided.

  As shown in FIG. 3, the seismic isolation bearing 6 segregates the bridge girder 3 by the elastic shear deformation in the horizontal direction H of the laminated rubber 16 against the relative vibration displacement in the horizontal direction H with respect to the pier 5 of the bridge girder 3. It is supposed to be.

  The buckling mechanism 7 is in contact with the circumferential surface 32 of the bridge girder side mounting plate 18 in the direction perpendicular to the bridge axis H1 at one end 31 so as to be slidable in the bridge axis direction (direction along the bridge axis) H2 or about 5 mm. And the other end portion 33 are rotatable members 35 and 36 that are rotatable in the R direction with respect to the pier 5 via the pair of support bases 34 and the pier side mounting plate 20, and one end portion. In 37, it is attached to one end part 31 of each of the rotatable members 35 and 36 via a screw 38, and the other end part 39 is fixed to the pier 5 via a holding member 40 and the pier side mounting plate 20. In order to enable the buckling members 41 and 42 made of a plate-like body and the rotatable members 35 and 36 to rotate in the R direction with respect to the pier 5, the rotatable member 35 and Each of 36 includes a pair of support base 34 and pier side mounting plate 2. It is provided with a shaft member 43 which rotatably coupled to the pier 5 via.

  The rotatable members 35 and 36 are arranged with the bridge girder side mounting plate 18 sandwiched in the bridge axis perpendicular direction H1, and the rotatable members arranged between the corresponding pair of support bases 34 in the bridge axis direction H2. Each of 35 and 36 is supported at the other end 33 by a pair of corresponding support bases 34 via a shaft member 43 so as to be rotatable in the R direction, and the rotatable member 35 is rotated in the R direction. Each of the pair of support bases 34 and the pair of support bases 34 that rotatably support the rotatable member 36 in the R direction is fixed to the pier-side mounting plate 20 via bolts 45. Yes.

  Each of the buckling members 41 and 42 prevents the rotation of the corresponding rotatable members 35 and 36 in the R direction when the external force F is below a certain value and prevents the rotation of the corresponding rotatable members 35 and 36 via the bridge girder mounting plate 18. While the elastic shearing deformation in the direction H1 perpendicular to the bridge axis 16 is prohibited, if the external force F exceeds a certain value, it buckles as shown in FIG. 4 and the corresponding rotatable members 35 and 36 in the R direction. Of the laminated rubber 16 is allowed to be elastically sheared in the direction H1 perpendicular to the bridge axis.

  In the bridge 50 having the above-described seismic isolation device 1 for a bridge, the bridge girder 3 extending in the bridge axis direction H2 and laid with railroad rails (rails), and the bridge pier 5, the bridge girder 3 is usually vertical. When the load in the direction V is supported by the seismic isolation bearing 6 and the bridge pier 5 vibrates in the bridge axis direction H2 due to the earthquake, as shown in FIG. When the bridge girder 3 is isolated by the displacement of the bridge axis direction H2 in the horizontal direction H relative to the lower surface 4 of the upper surface 2 due to shear deformation, and the pier 5 vibrates in the direction H1 perpendicular to the bridge axis due to the earthquake, the pier 5 When the external force F in the direction H1 perpendicular to the bridge axis applied to the pier side mounting plate 20 via a bridge is less than a certain value, the rotatable members 35 and 36 are buckled without the buckling members 41 and 42 buckling. Stretched and supported by 41 and 42, seismic isolation support While the relative displacement in the bridge axis perpendicular direction H1 with respect to the lower surface 4 of the upper surface 2 is prohibited by the abutment of the bridge girder side mounting plate 18 on the rotatable members 35 and 36, the bridge pier 5 is perpendicular to the bridge axis due to the earthquake. If the external force F in the direction perpendicular to the bridge axis H1 applied to the pier-side mounting plate 20 via the pier 5 exceeds a certain value when it vibrates in H1, buckling members 41 and 42 as shown in FIG. And the corresponding rotatable members 35 and 36 are allowed to rotate in the R direction, and elastic shear deformation in the direction H1 perpendicular to the bridge axis of the laminated rubber 16 is allowed. A relative displacement in the direction H1 perpendicular to the bridge axis with respect to the lower surface 4 of the upper surface 2 is allowed.

  According to the seismic isolation bearing device 1 for such a bridge, when the external force F in the direction perpendicular to the bridge axis H1 applied to the seismic isolation bearing 6 exceeds a certain value, the buckling mechanism 7 buckles and the upper surface of the seismic isolation bearing 6 is obtained. Since the relative displacement in the direction H1 perpendicular to the bridge axis with respect to the lower surface 4 of FIG. 2 is allowed, the seismic isolation function by the seismic isolation bearing 6 can be exhibited in extremely strong earthquakes, resulting in damage to the bridge 50 The bridge against the lower surface 4 of the upper surface 2 of the base isolation bearing 6 without buckling when the external force F in the direction H1 perpendicular to the bridge axis H1 added to the base isolation bearing 6 is below a certain value. Since the relative displacement in the direction perpendicular to the axis H1 is prohibited, the displacement of the bridge girder in the direction perpendicular to the axis H1 more than necessary for the bridge girder 3 can be prevented against earthquakes that occur several times during the lifetime. In addition to maintaining the function of the bridge 50, the buckling of the buckling members 41 and 42 Therefore, the buckling members 41 and 42 are only buckled because the pivotable members 35 and 36 are allowed to rotate and elastic shear deformation in the direction H1 perpendicular to the bridge axis of the laminated rubber 16 is allowed. As a result, damage to the bridge 50 can be prevented. As a result, the buckling members 41 and 42 that have been buckled can be replaced quickly.

  In the above example, each of the rotatable members 35 and 36 can be rotated in the R direction with respect to the pier 5 via the shaft member 43. Instead, as shown in FIG. Each of the possible members 35 and 36 includes a plastically deformable portion 62 including a constricted portion 61, and when the external force F applied to the seismic isolation bearing 6 exceeds a certain value, the plastically deformable portion 62 performs plastic deformation. (Bending) may be made to be rotatable in the R direction with respect to the pier 5. In this case, each of the rotatable members 35 and 36 is integrated with a corresponding pair of support bases 34. It is good to form. The constricted portion 61 of the plastically deformable portion 62 of this example is formed by a cut portion 63 provided in each of the rotatable members 35 and 36.

  In the above example, the seismic isolation bearing 6 is constituted by the laminated rubber 16 in which a plurality of steel plates 14 and a plurality of elastic layers 15 are alternately laminated, but instead, as shown in FIG. The seismic isolation bearing 6 may be constituted by the laminated rubber 16 in which the lead plug 65 is embedded. According to the seismic isolation bearing 6 having the lead plug 65, the vibration of the bridge girder 3 is effectively attenuated by the lead plug 65. be able to.

  Further, in the above example, the buckling mechanism 7 is constituted by the rotatable members 35 and 36 arranged with the bridge girder side mounting plate 18 sandwiched in the direction H1 perpendicular to the bridge axis. Instead, as shown in FIG. In addition, a plurality of seismic isolation bearings 6 are provided between the bridge girder 3 and the pier 5 in the same manner as described above, and an engagement block 72 having a surface 71 perpendicular to the bridge axis perpendicular direction H1 is integrally provided. The bridge girder 3 is constructed, and each end 31 is brought into contact with a surface 71 perpendicular to the bridge axis perpendicular direction H1 of the bridge girder 3 so as to be slidable in the bridge axis direction H2 or with a slight gap of about 5 mm. The buckling mechanism 7 may be configured by providing the rotatable members 35 and 36. As shown in FIG. 7, even if the buckling mechanism 7 is constituted by the rotatable members 35 and 36 arranged with the engagement block 72 sandwiched in the direction H1 perpendicular to the bridge axis, the pier 5 is caused by an earthquake as described above. Is oscillating in the direction perpendicular to the bridge axis H1, and when the external force F in the direction perpendicular to the bridge axis H1 applied to the pier side mounting plate 20 via the pier 5 is less than a certain value, the buckling members 41 and 42 are The pivotable members 35 and 36 are stretched and supported by the buckling members 41 and 42 without buckling, and the relative displacement in the direction H1 perpendicular to the bridge axis with respect to the lower surface 4 of the upper surface 2 of the seismic isolation bearing 6 is rotatable. On the other hand, when the pier 5 vibrates in the direction H1 perpendicular to the bridge axis H1 due to the earthquake, the pier 5 is oscillated in the direction perpendicular to the bridge axis H1 due to the earthquake, and is applied to the pier side mounting plate 20 via the pier 5 When the external force F of H1 exceeds a certain value The buckling members 41 and 42 are buckled and the corresponding rotatable members 35 and 36 are allowed to rotate in the R direction, and elastic shear deformation in the direction H1 perpendicular to the bridge axis of the laminated rubber 16 is allowed, Thus, relative displacement in the direction perpendicular to the bridge axis H1 with respect to the lower surface 4 of the upper surface 2 of the seismic isolation bearing 6 is allowed.

  In the example of FIGS. 1 to 6, a single base isolation bearing 6 is provided between the bridge girder 3 and the bridge pier 5 to constitute the bridge base isolation system 1, but instead of this, FIGS. In the example shown in FIG. 7, a plurality of seismic isolation bearings 6 may be provided between the bridge girder 3 and the pier 5 as shown in FIG. A plurality of seismic isolation bearings 6 are provided between the bridge girder 3 and the bridge pier 5 to constitute the seismic isolation bearing device 1 for a bridge. Instead, as shown in FIGS. Alternatively, a single base isolation bearing 6 may be provided between the bridge girder 3 and the bridge pier 5 to constitute the bridge base isolation system 1. Further, in the above example, the buckling mechanism 7 is provided on the side of the bridge pier 5. However, it may replace with this and may be provided in the bridge girder 3 side, and the engagement block 72 may be provided in the bridge pier 5 side instead of or together with the bridge girder 3 side.

  Moreover, in the example of FIGS. 1-6, although the buckling mechanism 7 which pinched | interposed the single seismic isolation bearing 6 was provided and the seismic isolation support apparatus 1 for bridges was comprised, instead of this, as shown in FIG. A buckling mechanism 7 is provided with two seismic isolation bearings 6 interposed therebetween, and one end portion 31 of the rotatable member 35 supported by the buckling member 41 is supported around the bridge girder side mounting plate 18 of one seismic isolation support 6. One end 31 of the rotatable member 35 that is stretched and supported by the buckling member 42 while facing the surface 32 is made to face the peripheral surface 32 of the bridge girder side mounting plate 18 of the other seismic isolation bearing 6 so as to isolate the bridge. The bearing device 1 may be configured. The bridge-based seismic isolation device 1 shown in FIG.

It is front explanatory drawing of the preferable Example of this invention. It is left side explanatory drawing of the Example shown in FIG. It is operation | movement explanatory drawing of the Example shown in FIG. It is operation | movement explanatory drawing of the Example shown in FIG. It is side explanatory drawing of other preferable Example of this invention. It is side surface explanatory drawing of other Example of preferable this invention. It is side surface explanatory drawing of other Example of preferable this invention. It is side surface explanatory drawing of other Example of preferable this invention.

Explanation of symbols

1 Seismic isolation device for bridge 2 Upper surface 3 Bridge girder 4 Lower surface 5 Bridge pier 6 Seismic isolation bearing 7 Buckling mechanism

Claims (15)

  The bridge girder is fixed to the bridge girder on the upper surface and the bridge pier on the lower surface, and supports the vertical load of the bridge girder, while relative to the vibration displacement in the horizontal direction of the bridge girder relative to the bottom of the bridge girder. Seismic isolation bearing that segregates the bridge girder by horizontal displacement and external force applied to the seismic isolation bearing that intersects the bridge axis and causes the displacement in the seismic isolation bearing Is below a certain value, the displacement of the seismic isolation bearing in the crossing direction of the bridge axis is prohibited, but if the external force applied to the seismic isolation bearing exceeds a certain value, it will buckle and the seismic isolation bearing A seismic isolation bearing device for a bridge comprising a buckling mechanism disposed between a bridge girder and a bridge pier so as to allow the displacement in the direction of crossing the bridge axis.   The seismic isolation bearing includes a laminated rubber in which steel plates and elastic layers are alternately laminated, a bridge girder side mounting plate that is provided on one end face in the laminating direction of the laminated rubber and is attached to the bridge girder. And a pier side mounting plate provided on the other end surface in the stacking direction of the laminated rubber and adapted to be attached to the pier, and the buckling mechanism has a bridge girder side mounting plate or The pier side mounting plate faces the circumferential surface of the bridge axis crossing direction, and at the other end is a rotatable member that is rotatable with respect to the pier or bridge girder, and at one end is attached to one end of the rotatable member. And a buckling member that is fixed to the pier or bridge girder at the other end, and the buckling member is a rotatable member when the external force is less than a certain value. Blocking rotation and preventing the bridge girder side mounting plate or pier side While prohibiting shear deformation of the laminated rubber in the crossing direction of the bridge axis through the attached plate, if the external force exceeds a certain value, it buckles and allows the rotatable member to rotate, allowing the turning of the rotatable rubber to the crossing direction of the bridge axis. The seismic isolation bearing device for a bridge according to claim 1, wherein shear deformation of the bridge is allowed.   The buckling member includes a plate-like body that is fixed to one end portion of the rotatable member at one end portion and fixed to a bridge pier or a bridge girder at the other end portion. Seismic isolation device for bridges.   The buckling mechanism includes a shaft member that rotatably connects the rotatable member to the pier or the bridge girder so that the rotatable member can rotate with respect to the pier or the bridge girder. Seismic isolation device for bridges as described in 1.   The seismic isolation bearing device for bridges according to claim 2 or 3, wherein the pivotable member includes a plastically deformable portion so as to be pivotable with respect to the bridge pier or the bridge girder.   The seismic isolation bearing device for a bridge according to claim 5, wherein the plastically deformable portion includes a constricted portion.   It is designed to be used for bridge girders or piers that have a plane perpendicular to the crossing direction of the bridge axis, and the buckling mechanism faces the plane perpendicular to the crossing direction of the bridge girder or pier at one end and the other. A pivotable member that can pivot with respect to the pier or bridge girder at the end, and is attached to one end of the pivotable member at one end and fixed to the pier or bridge girder at the other end. The buckling member is perpendicular to the crossing direction of the bridge girder or bridge pier by preventing the rotation of the rotatable member when the external force is below a certain value. The above-mentioned displacement in the crossing direction of the bridge base of the seismic isolation bearing is prohibited through the surface to be supported, but if the external force exceeds a certain value, the bridge shaft of the base isolation bearing is allowed to buckle and allow the pivotable member to rotate. The bridge according to claim 1, wherein the displacement in the crossing direction is allowed. Shin bearing apparatus.   The buckling member includes a plate-like body that is fixed to one end of the rotatable member at one end and fixed to a bridge pier or a bridge girder at the other end. Seismic isolation device for bridges.   The buckling mechanism includes a shaft member that rotatably connects the rotatable member to the pier or the bridge girder so that the rotatable member can rotate with respect to the pier or the bridge girder. Seismic isolation device for bridges as described in 1.   The seismic isolation bearing device for a bridge according to claim 7 or 8, wherein the pivotable member includes a plastically deformable portion so as to be pivotable with respect to the bridge pier or the bridge girder.   The seismic isolation bearing device for a bridge according to claim 11, wherein the plastically deformable portion includes a constricted portion.   The seismic isolation bearing includes a laminated rubber in which steel plates and elastic layers are alternately laminated, a bridge girder side mounting plate that is provided on one end face in the laminating direction of the laminated rubber and is attached to the bridge girder. And a pier side mounting plate that is provided on the other end surface of the laminated rubber in the laminating direction and is adapted to be attached to the pier. The seismic isolation bearing device for a bridge according to any one of claims 7 to 11, wherein the bridge girder is seismically isolated by shear deformation in the horizontal direction of the laminated rubber.   The seismic isolation bearing device for bridges according to any one of claims 1 to 12, wherein the seismic isolation bearing includes at least one lead plug.   A bridge comprising a bridge girder, a pier, and the seismic isolation bearing device for a bridge according to any one of claims 1 to 13.   The bridge according to claim 14, wherein railroad rails are laid on the bridge girder.

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