JP6275314B1 - Seismic reinforcement structure for bridges - Google Patents

Abstract

The present invention provides a seismic reinforcement structure for a bridge that can improve seismic resistance and is easy to construct. A seismic reinforcing structure 10 for a bridge 1 having a bridge girder 2 extending in a bridge axial direction X and a rocking pier 3 supporting the bridge girder 2, comprising an intermediate portion of the bridge girder 2 in the bridge axial direction X and a ground G And a damper 11 that absorbs seismic energy in the direction Y perpendicular to the bridge axis of the bridge girder 2 with respect to the ground G. [Selection] Figure 2

Description

  The present invention relates to a seismic reinforcement structure for a bridge having a rocking pier.

  For example, as bridges and railway bridges used for expressways, a bridge girder extending in the direction of the bridge axis, a plurality of rocking piers that support the middle part of the bridge girder in the direction of the bridge axis, and an abutment that supports both ends of the bridge girder in the direction of the bridge axis, There is a known bridge. In order to restrict the displacement of the bridge girder in the direction perpendicular to the bridge axis, the abutment is provided with a pair of limiting members that sandwich the bridge girder from both sides in the direction perpendicular to the bridge axis.

In recent years, seismic reinforcement of bridges in preparation for large-scale earthquakes has been demanded. The rocking pier is formed by attaching pivot bearings each having a hinge structure to the upper and lower ends of the column. That is, the rocking pier is pin-joined to the bridge girder or the pier foundation. Therefore, no force such as shear force is generated, and the bridge girder can be reasonably supported by the rocking pier.
On the other hand, the pivot bearing has a vertical force support function and a rotation function, but does not substantially have a horizontal force support function. Therefore, in a conventional bridge having a rocking pier, when an earthquake or the like occurs, the rocking pier greatly shakes in the horizontal direction, and the bridge girder is greatly displaced in the direction perpendicular to the bridge axis with respect to the ground. As a result, when seismic energy that can normally be assumed is input, the energy is absorbed, but when extremely large seismic energy exceeding the expected value is input, the limiting member provided on the abutment is damaged by the bridge girder. Or the bridge girder may get over the restricting member and shift significantly.

  In the following Non-Patent Document 1, it is proposed that the rocking pier is covered with concrete in order to provide seismic reinforcement of the bridge including the rocking pier. In this case, since the rocking pier can be prevented from shaking in the horizontal direction by the concrete, the earthquake resistance of the bridge can be improved.

East Japan Expressway Co., Ltd. Tohoku branch office Fukushima management office, "Seismic reinforcement of bridges with rocking piers", [online], February 10, 2017, [Search June 8, 2017], Internet <URL: http: //www.pref.fukushima.lg.jp/uploaded/attachment/202424.pdf>

  In the seismic strengthening method described in Non-Patent Document 1, since concrete is placed around the rocking pier, a large-scale construction is required in which a heavy machine is carried in the vicinity of the rocking pier. In addition, it is necessary to strike the foundation of the rocking pier in order to cast concrete. Therefore, the construction is complicated and the construction period may be prolonged.

  This invention is made | formed in view of the situation mentioned above, Comprising: It aims at providing the earthquake-proof reinforcement structure of the bridge which can improve earthquake resistance and is easy to construct.

In order to solve the above problems, the present invention proposes the following means.
The seismic reinforcement structure according to the present invention is a seismic reinforcement structure for a bridge having a bridge girder extending in the direction of the bridge axis and a rocking pier that supports the bridge girder, and includes an intermediate portion of the bridge girder in the direction of the bridge axis and the ground. A damper that is connected and absorbs seismic energy in a direction perpendicular to the bridge axis of the bridge girder with respect to the ground , and the damper is arranged outside the bridge girder in a top view when the bridge girder is viewed from above. To do.

The damper can reduce the vibration in the direction perpendicular to the bridge axis of the bridge girder and reduce the displacement of the bridge girder in the direction perpendicular to the bridge axis with respect to the ground. Therefore, it is possible to prevent the bridge girder from shifting or falling due to an unexpected large earthquake. As a result, the earthquake resistance of the bridge can be improved by the seismic reinforcement structure.
In addition, since the damper absorbs the seismic energy of the bridge girder, the load acting on the bridge girder from the damper can be reduced. Therefore, damage to the bridge girder due to the load from the damper can be reduced.
In addition, the bridge can be seismically strengthened simply by connecting the damper to the bridge girder and the ground. For example, when a bridge is provided on a highway, a damper can be constructed using a median strip. Therefore, the construction of the seismic reinforcement structure is easy.

In addition, by supporting the bridge girder from the outside with a damper, the displacement of the bridge girder in the direction perpendicular to the bridge axis with respect to the ground can be more effectively reduced.
A damper can be installed from the outside of the bridge girder. Heavy equipment for installing the damper need only be carried outside the bridge girder, and does not need to be carried inside the bridge girder. Therefore, the construction of the earthquake resistant reinforcement structure becomes easier.
Moreover, the fixed position with respect to the ground of a damper can be made into the arbitrary positions in the outer side of a bridge girder. Therefore, for example, when a buckling restrained brace is employed as the damper, the inclination angle of the damper with respect to the ground can be arbitrarily set. For example, if the inclination angle of the damper with respect to the ground is reduced and the fixed position of the damper with respect to the ground is moved away from the bridge girder, the seismic energy in the direction perpendicular to the bridge axis of the bridge girder can be efficiently transmitted to the damper. The seismic energy in the direction perpendicular to the bridge axis can be absorbed effectively.

In the seismic reinforcement structure according to the present invention, a damper foundation on which the damper is fixed may be provided on the ground independently of the bridge foundation of the bridge.
In this case, the foundation work for installing the damper may be performed only on the portion of the ground where the damper is fixed, and the construction of the seismic reinforcement structure becomes easier.

In the earthquake-proof reinforcement structure according to the present invention, the damper may be directly attached to the bridge girder.
For example, if the bridge girder is made of H-shaped steel and the bridge girder and the ground are connected by H-shaped steel braces, the load acting on the bridge girder from the H-shaped steel braces increases. The bridge girder can be severely damaged by the load. In the present invention, since the bridge girder and the ground are connected by the damper that absorbs the seismic energy of the bridge girder, the load acting on the bridge girder from the damper can be reduced. Therefore, even if a damper is directly attached to a bridge girder without providing a reinforcing member on the bridge girder, damage to the bridge girder due to a load from the damper can be reduced. By attaching the damper directly to the bridge girder in this way, the construction of the seismic reinforcement structure becomes easier.

In the seismic reinforcement structure according to the present invention, the damper may include a pair of dampers provided so as to sandwich the bridge girder from both sides in a direction perpendicular to the bridge axis.
By supporting the bridge girder from both sides in the direction perpendicular to the bridge axis with a pair of dampers, the displacement of the bridge girder in the direction perpendicular to the bridge axis with respect to the ground can be reduced more effectively. Moreover, the load which acts on a bridge girder from one damper can be disperse | distributed. Therefore, damage to the bridge girder due to the load from the damper can be further reduced.

Moreover, the earthquake-proof reinforcement structure which concerns on this invention WHEREIN: The said damper may be attached to the said bridge girder in the position which corresponds to the said rocking pier and the said bridge axial direction.
The portion of the bridge girder where the rocking pier is provided is stiffened and stiffened by a reinforcing member or the like to support the load. When a damper is attached to this stiffening part, the seismic energy of the bridge girder is efficiently transmitted to the damper. Therefore, the damper can effectively absorb the seismic energy of the bridge girder. Moreover, the damage of the bridge girder by the load from a damper can be reduced more. Moreover, it is not necessary to reinforce the bridge girder for installing the damper, and the construction of the seismic reinforcement structure becomes easier.

In the earthquake-proof reinforcement structure according to the present invention, the damper may be a buckling restrained brace.
When the buckling restrained brace receives an axial force of a predetermined value or more, the buckling restrained brace plastically deforms while preventing buckling and absorbs seismic energy. That is, there is an upper limit on the load acting on the bridge girder from the buckling restraint brace, and no load exceeding a predetermined value is applied to the bridge girder from the buckling restraint brace. Therefore, damage to the bridge girder due to the load from the buckling restrained brace can be reduced.

In the earthquake-proof reinforcement structure according to the present invention, the damper may be a hydraulic damper.
In the earthquake-proof reinforcement structure according to the present invention, the damper may be a friction damper.
The seismic reinforcement structure according to the present invention is a seismic reinforcement structure for a bridge having a bridge girder extending in the direction of the bridge axis and a rocking pier that supports the bridge girder, wherein the bridge girder has an intermediate portion and a ground surface. And a damper that absorbs seismic energy in a direction perpendicular to the bridge axis of the bridge girder with respect to the ground. The damper is directly attached to the bridge girder.
The seismic reinforcement structure according to the present invention is a seismic reinforcement structure for a bridge having a bridge girder extending in the direction of the bridge axis and a rocking pier that supports the bridge girder, wherein the bridge girder has an intermediate portion and a ground surface. And a damper that absorbs seismic energy in the direction perpendicular to the bridge axis of the bridge girder with respect to the ground, and the damper has a pair of dampers provided so as to sandwich the bridge girder from both sides in the direction perpendicular to the bridge axis. It is characterized by.

  It is possible to provide a seismic reinforcement structure for a bridge that can improve earthquake resistance and is easy to construct.

It is a top view of a seismic strengthening bridge unit provided with a bridge and a seismic strengthening structure concerning one embodiment of the present invention. It is the II-II cross-sectional arrow view shown in FIG. 1, Comprising: It is the figure which looked at the rocking pier front. It is a figure which shows the behavior of a bridge and an earthquake-proof reinforcement structure at the time of an earthquake, (a) is a general view, (b) is sectional drawing. It is a graph which shows an example of the history restoring force characteristic of the buckling restraint brace which concerns on one Embodiment of this invention, and an example of the history restoring force characteristic of the H-section steel brace as a comparative example.

  Hereinafter, an embodiment of a seismic reinforcement structure for a bridge according to the present invention will be described with reference to FIGS. In all the drawings below, the thicknesses and dimensions of the components are adjusted to make the drawings easy to see.

FIG. 1 is a top view of a seismic strengthening bridge unit A including a bridge 1 and a seismic strengthening structure 10. 2 is a cross-sectional view taken along the line II-II shown in FIG.
The seismic strengthening bridge unit A according to this embodiment includes a bridge 1 and a seismic strengthening structure 10 used for seismic strengthening of the bridge 1.

The bridge 1 is an existing bridge that is used, for example, on a highway on which an automobile travels. The bridge 1 may be a newly established bridge. As shown in FIG. 1, the bridge 1 includes a bridge girder 2 extending in the bridge axis direction X, a rocking pier 3 that supports an intermediate portion 2 a of the bridge girder 2 in the bridge axis direction X, and a bridge girder 2 in the bridge axis direction X. And abutments 4 and 5 that support the one end 2b and the second end 2c.
As shown in FIGS. 1 and 2, the seismic reinforcement structure 10 connects the intermediate portion 2 a of the bridge girder 2 and the ground G and absorbs seismic energy in the direction perpendicular to the bridge axis Y of the bridge girder 2 with respect to the ground G. A restraint brace (damper) 11 is provided.
The bridge axis direction X is a direction in which the bridge girder 2 extends. For example, the bridge axis perpendicular direction Y is a direction along the upper surface of the bridge girder 2 and orthogonal to the bridge axis direction X. The direction Y perpendicular to the bridge axis is the same as the width direction of the bridge girder 2. For example, the bridge axis direction X and the bridge axis perpendicular direction Y are directions along the horizontal plane.

As shown in FIGS. 1 and 2, the intermediate portion 2 a of the bridge girder 2 is supported from below by a rocking pier 3. The first end 2b of the bridge beam 2 is supported by the first abutment 4 so that displacement in the bridge axis direction X and the bridge axis perpendicular direction Y is limited. The second end 2c of the bridge girder 2 can be displaced in the bridge axis direction X by the second abutment 5 but is supported so that the displacement in the bridge axis perpendicular direction Y is limited.
For the bridge girder 2, for example, H-section steel can be used.

As shown in FIG. 2, the rocking pier 3 includes a column 3a extending in the vertical direction, a first pivot bearing 3b attached to the upper end of the column 3a, and a second pivot bearing 3c attached to the lower end of the column 3a. Prepare. Each of the pivot bearings 3b and 3c includes an upper rod having a lower surface formed in a concave spherical shape and a lower rod having an upper surface formed in a convex spherical shape. The upper arm of the first pivot support 3 b is fixed to the lower surface of the bridge girder 2. Thereby, the bridge girder 2 and the rocking pier 3 are pin-joined by the first pivot support 3b. The lower arm of the second pivot support 3c is fixed to the pier foundation F1 provided on the ground G. Thereby, the pier foundation F1 and the rocking pier 3 are pin-joined by the second pivot support 3c.
As shown in FIG. 1, a plurality (three in the present embodiment) of rocking piers 3 are arranged side by side in the direction Y perpendicular to the bridge axis to form a pier set 30. A plurality (two in this embodiment) of bridge pier sets 30 are arranged with a gap in the bridge axis direction X.

  As shown in FIG. 1, the first abutment 4 is provided with a first restricting member 6 that restricts displacement of the bridge girder 2 in the bridge axis direction X and the bridge axis perpendicular direction Y. The second abutment 5 is provided with a pair of second restricting members 7 that sandwich the bridge girder 2 from both sides of the bridge axis perpendicular direction Y and restrict displacement of the bridge girder 2 in the bridge axis perpendicular direction Y. The pair of second limiting members 7 does not limit the displacement of the bridge girder 2 in the bridge axis direction X. Therefore, on the second abutment 5 side, the bridge girder 2 is supported so as to be displaceable in the bridge axis direction X although the displacement in the bridge axis perpendicular direction Y is limited.

  The buckling restraint brace 11 is a brace-type vibration damper formed in a long shape. The buckling-restraining brace 11 includes, for example, a central steel material extending along the axis, a steel pipe that covers from the outer peripheral side with both ends of the central steel material protruding, and a filler such as concrete or mortar filled inside the steel pipe. And comprising. The central steel material receiving the axial force is plastically deformed while being prevented from out-of-plane deformation and buckling by being restrained by the steel pipe and the filler from the outer peripheral side. As a result, when the buckling restrained brace 11 receives an axial force of a predetermined value or more, the buckling restrained brace 11 is plastically deformed while preventing buckling and absorbs seismic energy.

As shown in FIGS. 1 and 2, the first end 11 a of the buckling restrained brace 11 is attached to the side surface 2 d of the bridge girder 2. The first end 11a is attached to the side surface 2d at a position coinciding with the rocking pier 3 (pier pier set 30) and the bridge axis direction X. The first end 11a is attached to the side surface 2d by, for example, a bolt or a pin. The first end 11a is directly attached to the side surface 2d without providing a reinforcing member on the side surface 2d.
The second end 11 b of the buckling restrained brace 11 is attached to a damper base F <b> 2 provided on the ground G and is fixed to the ground G. The second end 11b is also attached to the damper foundation F2 at a position coinciding with the rocking pier 3 (pier pier set 30) and the bridge axis direction X. The second end 11b is attached to the damper base F2 with, for example, a bolt or a pin. The damper foundation F2 is reinforced by, for example, a steel pipe pile (not shown). The damper foundation F2 is provided independently of the bridge pier foundation F1 and the bridge foundation FB of the bridge 1 including the abutment foundations of the abutments 4 and 5.

As shown in FIG. 1, the buckling restrained brace 11 is disposed outside the bridge beam 2 in a top view when the bridge beam 2 is viewed from above. The buckling restrained brace 11 extends in the direction Y perpendicular to the bridge axis when the bridge girder 2 is viewed from above. A pair of buckling restraint braces 11 are provided so as to sandwich the bridge girder 2 from both sides in the direction Y perpendicular to the bridge axis. In the present embodiment, four buckling restrained braces 11 are provided for the bridge 1.
As shown in FIG. 2, the buckling restrained brace 11 is disposed to be inclined with respect to the ground G when the bridge girder 2 is viewed from the bridge axial direction X. The inclination angle θ of the buckling restrained brace 11 with respect to the ground G is, for example, 45 degrees. Further, for example, the axial length L1 of the buckling restrained brace 11 is 9899 mm, the distance L2 in the bridge axis perpendicular direction Y between the first end 11a and the second end 11b is 7000 mm, and the first end 11a and the first end The vertical distance L3 between the two ends 11b is 7000 mm. The dimensions of the buckling restrained brace 11 are appropriately set according to the dimensions of the bridge 1.

Next, the operation of the seismic reinforcement structure 10 when an earthquake occurs will be described.
When an earthquake occurs, the bridge 1 vibrates with respect to the ground G. The bridge girder 2 and the rocking pier 3 are pin-joined by a first pivot support 3b, and the pier foundation F1 and the rocking pier 3 are pin-joined by a second pivot support 3c. The pivot bearings 3b and 3c have a vertical force support function and a rotation function, but do not substantially have a horizontal force support function. Therefore, when an earthquake occurs, as shown in FIG. 3, the rocking pier 3 greatly shakes in the horizontal direction, and the bridge girder 2 tends to be greatly displaced in the direction Y perpendicular to the bridge axis with respect to the ground G. The first end 2b and the second end 2c of the bridge girder 2 are limited in displacement in the direction perpendicular to the bridge axis Y by the abutments 4 and 5, but the intermediate part 2a of the bridge girder 2 is only pin-joined to the rocking pier 3 It is. Therefore, the displacement of the intermediate portion 2a in the direction perpendicular to the bridge axis Y is particularly large.
In this embodiment, the buckling restrained brace 11 of the seismic reinforcement structure 10 connects the intermediate portion 2a of the bridge girder 2 and the ground G. More specifically, the buckling restrained brace 11 is attached to the side surface 2d of the bridge girder 2 and supports the intermediate portion 2a of the bridge girder 2 from the Y direction perpendicular to the bridge axis. Further, the buckling restrained brace 11 absorbs the seismic energy in the direction Y perpendicular to the bridge axis of the bridge girder 2 with respect to the ground G. Therefore, the buckling restrained brace 11 can reduce the vibration in the bridge axis perpendicular direction Y of the bridge girder 2 and reduce the displacement in the bridge axis perpendicular direction Y of the intermediate portion 2a of the bridge girder 2 with respect to the ground G. As a result, even if an unexpected large earthquake occurs, the bridge girder 2 can be prevented from being displaced or dropped.
Moreover, since the buckling restraint brace 11 absorbs the seismic energy of the bridge girder 2, the load acting on the bridge girder 2 from the buckling restraint brace 11 can be reduced. Therefore, damage to the bridge girder 2 due to the load from the buckling restrained brace 11 can be reduced.

FIG. 4 shows an example of a history restoring force characteristic of the buckling restrained brace 11 according to the present embodiment and an example of a history restoring force characteristic of an H-section steel brace as a comparative example. In FIG. 4, the vertical axis indicates the load P, and the horizontal axis indicates the deformation δ.
As shown in FIG. 4, for example, when the buckling restraint brace 11 receives an axial force of 1400 kN or more, the buckling restraint brace 11 plastically deforms while preventing buckling and absorbs seismic energy. That is, in the seismic reinforcement structure 10 according to the present embodiment, a load of 1400 kN or more is not applied from the buckling restraint brace 11 to the bridge girder 2. Therefore, damage to the bridge girder 2 due to the load from the buckling restrained brace 11 can be reduced.

As the H-shaped steel brace of the comparative example, an H-shaped steel having an axial length of 9899 mm and an elastic limit on the compression side of 1400 kN was used. For example, the H-shaped steel brace of the comparative example has a web dimension of 250 mm, a flange dimension of 250 mm, a web thickness of 9 mm, a flange thickness of 14 mm, and a cross-sectional area of 9143 mm ² . The H-shaped steel brace of the comparative example is formed of an SN material (rolled steel for building structure (JIS G 3136)). In this case, the elastic limit of the compression side of the H-shaped steel braces of the comparative example is about 153N / mm ^2, yield point of tension side becomes 325N / mm ² or more. Therefore, the H-shaped steel brace of the comparative example buckles when a compression axial force of 1400 kN or more acts, but can withstand a tensile axial force of 2971 kN.
Similar to the buckling restrained brace 11 according to the present embodiment, a pair of comparative H-shaped steel braces are assumed to be provided so as to sandwich the bridge girder 2 from both sides in the direction Y perpendicular to the bridge axis. When a compressive axial force of 1400 kN or more acts on one H-shaped steel brace of a pair of H-shaped steel braces of a pair of comparative examples due to an earthquake, one H-shaped steel brace buckles. As a result, no compressive load is applied from one H-shaped steel brace to the bridge girder 2. Further, in this case, it is considered that a tensile axial force of 1400 kN or more is acting on the other H-shaped steel brace, but the other H-shaped steel brace can withstand up to 2971 kN against the tensile axial force. Will not surrender. As a result, a tensile load exceeding 1400 kN is applied from the other H-shaped steel brace to the bridge girder 2. Therefore, the bridge girder 2 may be greatly damaged by the load from the other H-shaped steel brace.
Thereafter, a compression axial force acts on the other H-shaped steel brace due to the shaking of the ground motion. Since one H-shaped steel brace is buckled, the bridge girder 2 is supported only by the other H-shaped steel brace. Therefore, the seismic energy of the bridge girder 2 is concentrated only on the other H-shaped steel brace. When a compression axial force of 1400 kN or more acts on the other H-shaped steel brace, the other H-shaped steel brace also buckles.

As described above, the seismic reinforcement structure 10 of the bridge 1 according to the present embodiment connects the intermediate portion 2a in the bridge axis direction X of the bridge girder 2 and the ground G, and the bridge axis perpendicular direction Y of the bridge girder 2 with respect to the ground G. The buckling restraint brace 11 (damper) which absorbs the seismic vibration energy of is provided.
The buckling restrained brace 11 can reduce the vibration of the bridge girder 2 in the direction perpendicular to the bridge axis Y, and can reduce the displacement of the bridge girder 2 in the direction perpendicular to the bridge axis Y with respect to the ground G. Therefore, it is possible to prevent the bridge girder 2 from being displaced or dropped due to an unexpected large earthquake. As a result, the earthquake resistance of the bridge 1 can be improved by the earthquake resistant reinforcement structure 10.
Moreover, since the buckling restraint brace 11 absorbs the seismic energy of the bridge girder 2, the load acting on the bridge girder 2 from the buckling restraint brace 11 can be reduced. Therefore, damage to the bridge girder 2 due to the load from the buckling restrained brace 11 can be reduced.
Moreover, the earthquake resistance reinforcement of the bridge 1 can be performed only by connecting the buckling restraint brace 11 to the bridge girder 2 and the ground G. For example, when the bridge 1 is provided on an expressway, the buckling restrained brace 11 can be constructed using a median strip. Therefore, construction of the earthquake-proof reinforcement structure 10 is easy.

Furthermore, in the present embodiment, the buckling restrained brace 11 is disposed outside the bridge beam 2 in a top view when the bridge beam 2 is viewed from above.
By supporting the bridge girder 2 from the outside with the buckling restraint brace 11, the displacement of the bridge girder 2 in the direction perpendicular to the bridge axis Y with respect to the ground G can be more effectively reduced.
Moreover, the buckling restraint brace 11 can be installed from the outside of the bridge girder 2. The heavy machinery for installing the buckling restraint brace 11 need only be carried into the outside of the bridge girder 2, and need not be carried into the inside of the bridge girder 2. Therefore, construction of the seismic reinforcement structure 10 becomes easier.
Moreover, the fixed position with respect to the ground G of the buckling restraint brace 11 can be set to an arbitrary position outside the bridge girder 2. Therefore, the inclination angle θ of the buckling restrained brace 11 with respect to the ground G can be arbitrarily set. For example, the inclination angle θ of the buckling restraint brace 11 with respect to the ground G is reduced, and the fixed position of the buckling restraint brace 11 with respect to the ground G (that is, the position of the second end 11b of the buckling restraint brace 11) is changed from the bridge girder 2. When the distance is away, the seismic energy in the direction perpendicular to the bridge axis Y of the bridge girder 2 can be efficiently transmitted to the buckling-restrained brace 11, and the seismic energy in the direction perpendicular to the bridge axis Y of the bridge girder 2 is effectively transmitted by the buckling-restrained brace 11. Can be absorbed into.

Furthermore, in the present embodiment, the ground G is provided with a damper foundation F2 to which the buckling restrained brace 11 is fixed independently of the bridge foundation FB of the bridge 1.
In this case, the foundation work for installing the buckling restraint brace 11 may be performed only on the portion of the ground G to which the buckling restraint brace 11 is fixed, and the construction of the seismic reinforcement structure 10 becomes easier.

Furthermore, in this embodiment, the buckling restraint brace 11 is directly attached to the bridge girder 2.
For example, when the bridge girder 2 is formed of H-shaped steel and the bridge girder 2 and the ground G are connected by the H-shaped steel brace, the load acting on the bridge girder 2 from the H-shaped steel brace increases. The bridge girder 2 may be greatly damaged by the load from the steel brace. In this embodiment, since the bridge girder 2 and the ground G are connected by the buckling constraint brace 11 that absorbs the seismic energy of the bridge girder 2, the load acting on the bridge girder 2 from the buckling constraint brace 11 can be reduced. Therefore, even if the buckling-restrained brace 11 is directly attached to the bridge girder without providing a reinforcing member on the bridge girder 2, damage to the bridge girder 2 due to the load from the buckling-restraining brace 11 can be reduced. By directly attaching the buckling-restrained brace 11 to the bridge girder 2 in this way, the construction of the seismic reinforcement structure 10 becomes easier.

Furthermore, in this embodiment, it has a pair of buckling restraint braces 11 provided as the buckling restraint braces 11 so as to sandwich the bridge girder 2 from both sides in the direction Y perpendicular to the bridge axis.
By supporting the bridge girder 2 from both sides in the direction perpendicular to the bridge axis Y with the pair of buckling restraint braces 11, the displacement of the bridge girder 2 in the direction perpendicular to the bridge axis Y with respect to the ground G can be more effectively reduced. Moreover, the load which acts on the bridge girder 2 from the one buckling restraint brace 11 can be disperse | distributed. Therefore, damage to the bridge girder 2 due to the load from the buckling restrained brace 11 can be further reduced.

Furthermore, in this embodiment, the buckling restrained brace 11 is attached to the bridge girder 2 at a position that coincides with the rocking pier 3 and the bridge axis direction X.
A portion of the bridge girder 2 where the rocking pier 3 is provided is stiffened and hardened by a reinforcing member or the like to support the load. When the buckling-restrained brace 11 is attached to this stiffening portion, the seismic energy of the bridge girder 2 is efficiently transmitted to the buckling-restraining brace 11. Accordingly, the seismic energy of the bridge girder 2 can be effectively absorbed by the buckling restraint brace 11. Moreover, damage to the bridge girder 2 due to the load from the buckling restrained brace 11 can be further reduced. Moreover, it is not necessary to reinforce the bridge girder 2 for the attachment of the buckling restrained brace 11, and the construction of the seismic reinforcement structure 10 becomes easier.

Furthermore, in this embodiment, the buckling restraint brace 11 is used as a damper.
When the buckling restraint brace 11 receives an axial force of a predetermined value or more, the buckling restraint brace 11 plastically deforms while preventing buckling and absorbs seismic energy. That is, there is an upper limit on the load acting on the bridge girder 2 from the buckling restraint brace 11, and no load greater than a predetermined value is applied from the buckling restraint brace 11 to the bridge girder 2. Therefore, damage to the bridge girder 2 due to the load from the buckling restrained brace 11 can be reduced.

In addition, this invention is not limited to the said embodiment described with reference to drawings, In the technical scope, various modifications can be considered.
For example, in the above embodiment, the buckling restrained brace 11 is used as the damper. However, as the damper, other forms capable of absorbing the seismic energy in the bridge axis perpendicular direction Y of the bridge girder 2 with respect to the ground G can be appropriately adopted, and are not limited to the buckling restrained brace 11. For example, as the damper, a hysteretic damping damper, a hydraulic damper, or a friction damper other than the buckling restrained brace may be used.

In the above embodiment, the buckling restrained brace 11 is disposed outside the bridge beam 2 in a top view. Further, the damper foundation F2 is provided independently of the bridge foundation FB of the bridge 1. However, the buckling restrained brace 11 may be disposed inside the bridge beam 2 in a top view. Further, the damper foundation F2 may be formed integrally with the bridge foundation FB, such as being provided on the bridge foundation FB of the bridge 1.
In the above embodiment, the pair of buckling restrained braces 11 are provided so as to sandwich the bridge girder 2 from both sides in the direction Y perpendicular to the bridge axis. However, the buckling restrained brace 11 may be provided only on one side of the bridge girder 2 in the direction perpendicular to the bridge axis Y. Further, the buckling restrained braces 11 may be provided in a zigzag manner on both sides of the bridge girder 2 in the direction Y perpendicular to the bridge axis.
In the above embodiment, the buckling restrained brace 11 is attached to the bridge girder 2 at a position that coincides with the rocking pier 3 and the bridge axis direction X. However, the buckling restrained brace 11 may be attached to an arbitrary position of the intermediate portion 2 a of the bridge girder 2.
In the above embodiment, the buckling restrained brace 11 is directly attached to the bridge girder 2. However, the buckling restrained brace 11 may be attached to the bridge girder 2 via another member such as a reinforcing member.

  In addition, it is possible to appropriately replace the constituent elements in the embodiment with known constituent elements without departing from the spirit of the present invention, and the above-described modified examples may be appropriately combined.

  DESCRIPTION OF SYMBOLS 1 ... Bridge 2 ... Bridge girder 2a ... Intermediate part 3 ... Rocking pier 10 ... Seismic reinforcement structure 11 ... Buckling restraint brace (damper) G ... Ground X ... Bridge axis direction Y ... Bridge axis perpendicular direction

Claims (10)

A seismic reinforcement structure for a bridge having a bridge girder extending in the direction of the bridge axis and a rocking pier supporting the bridge girder,
A damper that connects the middle portion of the bridge girder in the direction of the bridge axis and the ground, and absorbs seismic energy in a direction perpendicular to the bridge axis of the bridge girder with respect to the ground ,
The said damper is arrange | positioned in the outer side of the said bridge girder in the top view which looked at the said bridge girder from the upper direction, The earthquake-proof reinforcement structure characterized by the above-mentioned . Wherein the ground, earthquake-proof reinforcement structure according to claim 1, wherein the damper is a damper basis to be fixed, the bridge foundation of the bridge is characterized in that it is provided independently. The seismic reinforcement structure according to claim 1 or 2 , wherein the damper is directly attached to the bridge girder. The earthquake-resistant reinforcing structure according to any one of claims 1 to 3, wherein the damper includes a pair of dampers provided so as to sandwich the bridge girder from both sides in a direction perpendicular to the bridge axis. The seismic reinforcement structure according to any one of claims 1 to 4, wherein the damper is attached to the bridge girder at a position that coincides with the rocking pier and the bridge axis direction. The seismic reinforcement structure according to any one of claims 1 to 5 , wherein the damper is a buckling-restrained brace. The earthquake-resistant reinforcing structure according to any one of claims 1 to 5 , wherein the damper is a hydraulic damper. The earthquake-resistant reinforcing structure according to any one of claims 1 to 5 , wherein the damper is a friction damper.   A seismic reinforcement structure for a bridge having a bridge girder extending in the direction of the bridge axis and a rocking pier supporting the bridge girder,
  A damper that connects the middle portion of the bridge girder in the direction of the bridge axis and the ground, and absorbs seismic energy in a direction perpendicular to the bridge axis of the bridge girder with respect to the ground,
  The damper is directly attached to the bridge girder.   A seismic reinforcement structure for a bridge having a bridge girder extending in the direction of the bridge axis and a rocking pier supporting the bridge girder,
  A damper that connects the middle portion of the bridge girder in the direction of the bridge axis and the ground, and absorbs seismic energy in a direction perpendicular to the bridge axis of the bridge girder with respect to the ground,
  An earthquake-proof reinforcement structure comprising a pair of dampers provided as the dampers so as to sandwich the bridge girder from both sides in a direction perpendicular to the bridge axis.

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