JP2016216919A - Bridge fall prevention structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bridge fall prevention structure for preventing a fall of a bridge girder, and capable of reducing maintenance work after an earthquake.SOLUTION: When a bridge girder 20 forces up along an inclined plane 31 of a bridge girder restoration member 30 by slidably moving in the crossing direction with its extension direction by an earthquake, restoration force for returning the positional relationship between the bridge girder 20 and a support structure 10 to an original state, is generated by pulling down its bridge girder 20 along the inclined plane 31 so as not to excessively slidably move the bridge girder 20, and prevents a bridge fall from above the support structure 10. After settling the earthquake, the bridge girder 20 forced up along the inclined plane is restored to predetermined arrangement by sliding down along the inclined plane by its restoring force. That is, since this bridge fall prevention structure 100 can restore the bridge girder 20 to the predetermined arrangement on the support structure 10, restoration work such as returning the dislocated bridge girder 20 to a predetermined position is obviated, so that maintenance work after the earthquake can be reduced.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a falling bridge prevention structure that prevents a bridge girder on a support structure such as a pier or an abutment from falling.

Conventionally, as measures in preparation for large-scale earthquakes, measures have been taken to prevent bridge girders from falling off support structures such as piers and abutments.
As such a countermeasure, for example, a stopper (for example, a steel angle stopper) for restricting the movement of the bridge girder is installed between the bridge girder and the support structure supporting the bridge girder, and the bridge girder deviates from the support structure. A technique for preventing this is known (for example, see Patent Document 1).

  In addition, a technology is known in which a seismic isolation rubber support is installed between a bridge girder and a support structure that supports the bridge girder, and the bridge girder is elastically supported to prevent deviation from the support structure (for example, non-patent) Reference 1).

Japanese Patent Laying-Open No. 2002-167711 (FIG. 6)

Yokohama Rubber Co., Ltd. website, [Search on March 19, 2015], Internet <URL: https://www.yrc.co.jp/industrial/products/bridge_construction_05.html>

  However, when a stopper such as the above-mentioned Patent Document 1 is used, the inertial force of the bridge girder oscillated due to the earthquake is transmitted to the support structure through the stopper, and a large reaction force acts on the support structure so that the stopper or the support structure If things are damaged by damage, it will be necessary to restore the damaged parts after the earthquake.

  Moreover, even when the seismic isolation rubber bearing as in Non-Patent Document 1 was used, the bridge girder was greatly oscillated due to the earthquake, and when the seismic isolation rubber bearing exceeded the elastic deformation and was not restored after the earthquake, it was damaged. Recovery work such as exchanging things is necessary.

  An object of the present invention is to provide a falling bridge prevention structure that can prevent a bridge girder from dropping and reduce maintenance work after an earthquake.

In order to achieve the above object, the present invention provides:
A falling bridge prevention structure for preventing the bridge girder installed on the support structure from falling,
When the bridge girder slides in a direction intersecting with the extending direction, and the positional relation between the bridge girder and the support structure is shifted, the positional relation between the bridge girder and the support structure is caused by the weight of the bridge girder. A bridge girder restoring member on which an inclined surface for generating a restoring force to restore the original is formed is disposed on the support structure.

In the fall prevention structure having such a configuration, when the bridge girder slides in a direction intersecting with the extending direction due to the earthquake motion, the bridge girder moves up along the inclined surface of the bridge girder restoring member.
Gravity acts on the bridge girder that has been pushed up along the inclined surface of the bridge girder restoration member so that the bridge girder is pulled down along the inclined surface, and the weight relationship between the bridge girder and the support structure is based on the weight of the bridge girder. By generating the restoring force to return to, the bridge girder is prevented from sliding too much, and it is possible to prevent the bridge girder from falling from the support structure.
Then, after the earthquake has ceased, the bridge girder that has come up along the inclined surface slides down along the inclined surface due to the restoring force caused by gravity (self-weight), so that the bridge girder can be restored to a predetermined arrangement.
In other words, with such a structure that prevents falling bridges, it is possible to prevent the bridge girder from falling from the support structure due to an earthquake, and to restore the bridge girder to a predetermined arrangement on the support structure after the earthquake has subsided. Therefore, it is not necessary to perform restoration work to return the shifted bridge girder to a predetermined position, and maintenance work after the earthquake can be reduced.

The inclination angle of the inclined surface of the bridge girder restoring member is preferably 1 ° or more and 20 ° or less with respect to the upper surface of the support structure. If the inclination angle of the inclined surface is not less than 1 ° and not more than 20 °, the bridge girder can suitably move up and down along the inclined surface.
For example, if the inclination angle of the inclined surface is less than 1 °, the restoring force to restore the positional relationship between the bridge girder and the support structure is weak, and the bridge girder may get over the inclined surface and deviate from the bridge girder restoring member. is there.
On the other hand, if the inclination angle of the inclined surface exceeds 20 °, the bridge girder cannot move up along the inclined surface, and the bridge girder restoring member or the like may be loaded and damaged.

Also, preferably
The bridge girder restoring member is disposed such that at least a part of the inclined surface forms a pair with the bridge girder interposed therebetween, and the inclined surfaces forming the pair have inclinations that descend toward each other.

  Since the paired slopes have a slope that goes down toward each other, the bridge girder that has been slid to move up the slope is suitable for a predetermined arrangement between the paired slopes after the earthquake has ceased. Can be restored.

Also, preferably
A bridge girder-side inclined surface having the same inclination angle as the inclined surface is formed on the lower surface of the bridge girder that is installed on the bridge girder restoring member and faces the inclined surface.

  If a bridge girder-side inclined surface with the same inclination angle as the inclined surface of the bridge girder restoration member is formed on the lower surface of the bridge girder, the bridge girder will be erected vertically when sliding in the direction crossing the extending direction It is possible to slide while maintaining the posture.

Also, preferably
A flat plate member having smoothness is provided on at least one of the inclined surface and the bridge girder-side inclined surface.
For example, if a plate-like member is provided on at least one of the inclined surface of the bridge girder restoring member and the bridge girder side inclined surface of the lower surface of the bridge girder, when the bridge girder slides in a direction crossing the extending direction, the lower surface of the bridge girder Is in smooth sliding contact with the plate-like member, so that the bridge girder can move smoothly.

Also, preferably
A flat plate member having smoothness is provided on the inclined surface.
For example, if a plate-like member is provided on the inclined surface of the bridge girder restoring member, when the bridge girder slides in a direction intersecting with the extending direction, the bottom surface of the bridge girder smoothly contacts the plate-like member. It can move smoothly.

  ADVANTAGE OF THE INVENTION According to this invention, while preventing a bridge girder falling from on a support structure, the maintenance operation | work after an earthquake can be reduced.

It is a perspective view which shows the falling-bridge prevention structure of Embodiment 1. FIG. It is the front view which shows the crossing prevention structure of Embodiment 1 in partial cross section, and is a state (a) in which the bridge girder is in a predetermined arrangement, and a state (b) in which the bridge girder is pushed up along the inclined surface. It is a perspective view which shows the fallen bridge prevention structure of Embodiment 2. FIG. It is a front view which shows the fallen bridge prevention structure of Embodiment 2 in partial cross section, and is in a state (a) where the bridge girder is in a predetermined arrangement and a state (b) where the bridge girder is pushed up along the inclined surface. It is a perspective view which shows the fallen bridge prevention structure of Embodiment 3. FIG. It is the front view which shows the crossing prevention structure of Embodiment 3 in partial cross section, and is a state (a) in which the bridge girder is in a predetermined arrangement, and a state (b) in which the bridge girder is pushed up along the inclined surface. It is a front view which shows the modification of the fallen bridge prevention structure of Embodiment 2. FIG. It is a front view which shows the modification of the fallen bridge prevention structure of Embodiment 2. FIG.

  Hereinafter, with reference to the drawings, embodiments of the falling bridge prevention structure according to the present invention will be described in detail. However, the embodiments described below are given various technically preferable limitations for carrying out the present invention, but the scope of the present invention is not limited to the following embodiments and illustrated examples.

(Embodiment 1)
FIG. 1 is a perspective view showing the falling bridge prevention structure 100 in a partial cross-sectional view. FIG. 2 is a front view showing the falling bridge prevention structure 100 in a partial cross-sectional view.
The falling bridge prevention structure 100 is a structure that prevents the bridge girder 20 on the support structure 10 such as a pier or an abutment from falling due to an earthquake motion.

As shown in FIGS. 1 and 2A, the falling bridge prevention structure 100 according to the present embodiment includes a support structure 10, a bridge girder 20 installed on the support structure 10 via a gutter 50, and a bridge girder 20. The bridge girder restoring member 30 disposed on the support structure 10 in a pair with the arrangement sandwiching the plate, the plate-like member 40 provided on the bridge girder restoring member 30, and the like.
This fallen bridge prevention structure 100 is provided with a bridge girder restoring member 30 on the support structure 10 in order to prevent the existing bridge girder 20 installed on the support structure 10 via the fence 50 from falling. is there. That is, the falling bridge prevention structure 100 is provided with the bridge girder restoring member 30 so as to reinforce and repair the existing bridge girder 20 to prevent it from falling.
Note that when the bridge girder 20 is newly installed, the falling bridge prevention structure 100 may be constructed.
In this embodiment, a T girder is used as the bridge girder 20, and two bridge girder 20 are installed on the support structure 10. In addition, since the structure of the support structure 10, the bridge girder 20, and the eaves 50 is the same as a conventionally well-known thing, it is not explained in full detail here.

The bridge girder restoration member 30 is a member having rigidity made of, for example, a steel material or a concrete material. When the bridge girder restoration member 30 is disposed on the support structure 10, an inclined surface 31 inclined downward toward the bridge girder 20 (２０ 50) is provided. It is formed on the upper surface.
Specifically, the bridge girder restoring member 30 is disposed on the support structure 10 so that the inclined surface 31 forms a pair with the bridge girder 20 interposed therebetween, and the inclined surface 31 that forms the pair sandwiches the bridge girder 20. They are arranged symmetrically and have slopes that descend towards each other.
The inclination angle of the inclined surface 31 of the bridge girder restoring member 30 is preferably 1 ° or more and 20 ° or less with respect to the upper surface of the support structure 10.
Note that the bridge girder restoring member 30 is disposed in a state in which the inclined side surface of the inclined surface 31 is in contact with the side surface of the flange 50.

The plate-like member 40 is a thin plate having smoothness attached to the inclined surface 31 of the bridge girder restoring member 30. For example, a thin plate made of metal such as stainless steel, or a thin plate made of resin such as FRP (Fiber Reinforced Plastics) Can be used. In order to reduce the frictional resistance of the surface (upper surface) of the plate-like member 40, it is preferable to perform a known surface treatment such as fluorine coating.
And the height position of the upper surface of the inclined lower end side of the plate-shaped member 40 and the upper surface of the flange 50 is matched so that there is no step between the plate-shaped member 40 and the flange 50.

  In addition, when not using this plate-shaped member 40, in order to reduce the frictional resistance of the inclined surface 31, it forms so that the lower end side of the inclined surface 31 of the bridge girder restoring member 30 and the upper surface of the eaves 50 may correspond. It is preferable to apply a known surface treatment such as fluorine coating to the surface.

  Next, a mechanism for preventing a fallen bridge in the fallen bridge preventing structure 100 of the present embodiment will be described.

When the vibration due to the earthquake acts on the bridge girder 20 installed on the support structure 10 and the bridge girder 20 shakes on the support structure 10, the bridge girder 20 slides in a direction intersecting with the extending direction. For example, FIG. 2B shows a state in which the bridge girder 20 slides to the right in the drawing with respect to the support structure 10.
And the bridge girder 20 slid in the direction intersecting with the extending direction, for example, as shown in FIG. 2 (b), rides on the plate-like member 40 and moves up along the inclined surface 31 of the bridge girder restoring member 30. . FIG. 2B shows a state in which the bridge girder 20 slides to the right in the drawing and the inclined surface 31 (plate-like member 40) of the bridge girder restoring member 30 on the right side in the drawing is pushed up obliquely upward.
As described above, when the moving energy at which the bridge girder 20 slides is large, a part of the moving energy of the bridge girder 20 is converted into energy that the bridge girder 20 pushes up the inclined surface 31 to consume the moving energy of the bridge girder 20. It is supposed to be.

Furthermore, gravity acts on the bridge girder 20 that has been pushed up along the inclined surface 31 of the bridge girder restoring member 30 in a direction in which the bridge girder 20 is pulled down along the inclined surface 31 so as to return the bridge girder 20 to its original position. This prevents the bridge girder 20 from sliding too much.
That is, when the positional relationship between the bridge girder 20 and the support structure 10 is shifted, the inclined surface 31 of the bridge girder restoring member 30 restores the restoring force of the original positional relationship (arrow in FIG. 2B). It has a function to generate.

  Then, after the earthquake has stopped, the bridge girder 20 that has been placed on the plate-like member 40 and urged along the inclined surface 31 slides down the plate-like member 40 along the inclined surface 31 by its own weight, and has a predetermined arrangement (FIG. 2 (a)).

It should be noted that the material of the plate-like member 40 (metal, resin, etc.) and the inclination of the bridge girder restoring member 30 are selected so that the bridge girder 20 that is slid and moved by an earthquake preferably moves up and down the inclined surface 31. The inclination angle of the surface 31 is designed.
For example, under the condition that the inclination angle of the inclined surface 31 is the same, if the plate-like member 40 made of a material having a low friction coefficient is used, the bridge girder 20 can easily move up the inclined surface 31 and the plate-like member made of a material having a high friction coefficient. If 40 is used, it will be difficult for the bridge girder 20 to push up the inclined surface 31.
Further, under the same conditions for the material of the plate-like member 40, if the inclination angle of the inclined surface 31 is small and close to 0 °, the bridge girder 20 is likely to push up the inclined surface 31, and the inclination angle of the inclined surface 31 is large and 90 °. If it is closer, it will be difficult for the bridge girder 20 to push up the inclined surface 31.
And according to the assumed earthquake scale and the size and weight of the bridge girder 20, the material of the plate-like member 40 and the inclination angle of the inclined surface 31 of the bridge girder restoring member 30 are set appropriately, and the bridge girder 20 is preferably inclined. The surface 31 is adjusted so as to move up and down.

As described above, when the bridge girder 20 slides in a direction crossing the extending direction due to the earthquake motion, the bridge girder prevention structure 100 of the present embodiment uses a part of the movement energy of the bridge girder 20 by the bridge girder restoration member 30. It is possible to regulate the movement of the bridge girder 20 so that the bridge girder 20 does not slide too much by consuming the movement energy of the bridge girder 20 so as to convert the slanted surface 31 into energy that moves up.
In particular, the bridge girder 20 does not slide too much due to the gravity acting on the bridge girder 20 that has been pushed up along the inclined surface 31 of the bridge girder restoring member 30 so as to pull down the bridge girder 20 along the inclined surface 31. Thus, the bridge girder 20 can be prevented from falling from the support structure 10.
Then, after the earthquake has ceased, the bridge girder 20 that has been placed on the plate-like member 40 and moved up along the inclined surface 31 slides down the plate-like member 40 along the inclined surface 31 by its own weight. Can be restored.

  As described above, according to the falling bridge prevention structure 100 of the present embodiment, the bridge girder 20 can be prevented from falling from the support structure 10 due to the earthquake, and the bridge girder 20 can be supported by the support structure 10 after the earthquake has subsided. Since it can be restored to the predetermined arrangement above, the restoration work for returning the shifted bridge girder 20 to the predetermined position becomes unnecessary, and the maintenance work after the earthquake can be reduced.

(Embodiment 2)
Next, a second embodiment of the falling bridge prevention structure according to the present invention will be described. In addition, the same code | symbol is attached | subjected to the same part as Embodiment 1, and only a different part is demonstrated.

As shown in FIG. 3 and FIG. 4A, the falling bridge prevention structure 101 of this embodiment includes a support structure 10, a bridge girder restoring member 60 disposed on the support structure 10, and a bridge girder restoring member 60. And a bridge girder 21 and the like installed on the support structure 10 via the plate girder restoring member 60 and the plate member 41.
In this falling bridge prevention structure 101, a bridge girder restoring member 60 is disposed between the support structure 10 and the bridge girder 21 in order to prevent the bridge girder 21 installed on the support structure 10 from falling. That is, the falling bridge prevention structure 101 is a structure newly established by using a bridge girder 21 having a lower surface that is substantially V-shaped when viewed from the front and a bridge girder restoring member 60 having an upper surface that is substantially V-shaped when viewed from the front. There is a structure for preventing the bridge girder 21 from falling down.

The bridge girder restoring member 60 is a member having rigidity made of, for example, a steel material or a concrete material, and a pair of inclined surfaces that are inclined downward toward the bridge girder 21 when disposed between the support structure 10 and the bridge girder 21. 61 is formed on the upper surface.
Specifically, the bridge girder restoring member 60 is disposed so that at least a part of the inclined surface 61 forms a pair with the bridge girder 21 interposed therebetween, and the inclined surface 61 that forms the pair is symmetrical with the bridge girder 21 interposed therebetween. It has an inclination which is arranged and goes down towards each other. That is, when the bridge girder restoring member 60 is viewed from the front, the upper surface side on which the pair of inclined surfaces 61 are formed has a substantially V-shape.
The inclination angle of each inclined surface 61 of this bridge girder restoring member 60 is preferably 1 ° or more and 20 ° or less with respect to the upper surface of the support structure 10.

The plate-like member 41 is a thin plate having smoothness attached to the inclined surface 61 that is the upper surface of the bridge girder restoring member 60. For example, a metal thin plate such as stainless steel or a resin such as FRP (Fiber Reinforced Plastics). A thin plate made of metal can be used.
The plate-like member 41 is substantially V-shaped when viewed from the front, and is preferably subjected to a known surface treatment such as fluorine coating in order to reduce the frictional resistance of the surface (upper surface).
In addition, when not using the plate-shaped member 41, in order to reduce the frictional resistance of the inclined surface 61 of the bridge girder restoring member 60, it is preferable to perform well-known surface treatments, such as a fluorine coating.

The bridge girder 21 has a lower surface that is substantially V-shaped when viewed from the front.
Specifically, a bridge girder-side inclined surface 21 a having the same inclination angle as the inclined surface 61 is formed on the lower surface of the bridge girder 21 that is installed on the bridge girder restoring member 60 and faces the inclined surface 61. When sliding in the direction crossing the extending direction, the bridge girder-side inclined surface 21a is in sliding contact with the inclined surface 61 of the bridge girder restoring member 60 (here, the plate-like member 41 on the inclined surface 61). In order to reduce the frictional resistance of the bridge girder-side inclined surface 21a, it is preferable to perform a known surface treatment such as fluorine coating.

Even in such a fallen bridge prevention structure 101, when vibration due to an earthquake acts on the bridge girder 21 installed on the support structure 10, the bridge girder 21 slides in a direction crossing the extending direction, for example, As shown in FIG. 4B, the bridge girder 21 slides on the plate-like member 41 and moves up along the inclined surface 61 of the bridge girder restoring member 60.
Then, gravity acts on the bridge girder 21 that has been pushed up along the inclined surface 61 of the bridge girder restoring member 60 in a direction in which the bridge girder 21 is pulled down along the inclined surface 61 so as to return the bridge girder 21 to its original position. . That is, when the positional relationship between the bridge girder 21 and the support structure 10 is deviated, the inclined surface 61 of the bridge girder restoring member 60 restores the original positional relationship (an arrow in FIG. 4B). It has a function to generate.

With this falling bridge prevention structure 101, like the falling bridge prevention structure 100 of the first embodiment, a part of the moving energy of the bridge girder 21 is converted into energy that the bridge girder 21 pushes up the inclined surface 61 of the bridge girder restoring member 60. By consuming the kinetic energy of the bridge girder 21, the movement of the bridge girder 21 can be regulated so as not to slide too much.
Moreover, the bridge girder 21 does not slide too much because the gravity acts so that the bridge girder 21 pulled up along the inclined surface 61 of the bridge girder restoring member 60 is pulled down along the inclined surface 61. Thus, the bridge girder 21 can be prevented from falling from the support structure 10.
Then, after the earthquake has ceased, the bridge girder 21 can be restored to the predetermined arrangement on the support structure 10, so that no restoration work is required to return the shifted bridge girder 21 to the predetermined position. Maintenance work can be reduced.

(Embodiment 3)
Next, a third embodiment of the fallen bridge prevention structure according to the present invention will be described. In addition, the same code | symbol is attached | subjected to the same part as Embodiment 1, 2, and only a different part is demonstrated.

As shown in FIGS. 5 and 6A, the falling bridge prevention structure 102 according to the present embodiment includes a support structure 10, a bridge girder restoring member 60 disposed on the support structure 10, and a bridge girder restoring member 60. The plate member 41 provided on the bridge, the bridge girder 20 installed on the support structure 10 via the bridge girder restoring member 60 and the plate member 41, and the triangular prism shape fixed to the bottom surface of the bridge girder 20 The structure has a member 22 and the like.
In order to prevent the bridge girder 20 installed on the support structure 10 from being dropped, the falling bridge prevention structure 102 has a triangular columnar member 22 fixed to the bottom surface of the bridge girder 20 and the support structure 10 and the bridge girder 20 (triangular columnar member). 22), the bridge girder restoring member 60 is disposed. That is, the falling bridge prevention structure 102 is a structure in which the triangular columnar member 22 is fixed to the existing bridge girder 20 and the bridge girder restoring member 60 is provided to prevent the bridge girder 20 from falling. Note that the falling bridge prevention structure 102 may be newly provided by using the bridge girder 20 and the bridge girder restoring member 60 in which the triangular columnar member 22 is fixed on the bottom surface.

The triangular columnar member 22 has a lower surface that exhibits a substantially V shape when viewed from the front in a state of being fixed to the bridge girder 20.
Specifically, a bridge girder-side inclined surface 22a having the same inclination angle as the inclined surface 61 of the bridge girder restoring member 60 is formed on the lower surface of the bridge girder 20 to which the triangular columnar member 22 is integrally fixed. When 20 slides in a direction crossing the extending direction, the bridge girder-side inclined surface 22a is in sliding contact with the inclined surface 61 of the bridge girder restoring member 60 (here, the plate-like member 41 on the inclined surface 61). . In order to reduce the frictional resistance of the bridge girder-side inclined surface 22a, it is preferable to perform a known surface treatment such as fluorine coating.

Even in such a fallen bridge prevention structure 102, when vibration due to an earthquake acts on the bridge girder 20 installed on the support structure 10, the bridge girder 20 slides in a direction crossing the extending direction, for example, As shown in FIG. 6B, the bridge girder 20 on which the triangular prism-like member 22 is integrally fixed slides on the plate-like member 41 and moves up along the inclined surface 61 of the bridge girder restoring member 60.
Then, the bridge girder 20 that has come up along the inclined surface 61 of the bridge girder restoring member 60 is pulled along the inclined surface 61 so as to return the bridge girder 20 to its original position. Gravity acts in the downward direction. That is, when the positional relationship between the bridge girder 20 and the support structure 10 is displaced, the inclined surface 61 of the bridge girder restoring member 60 restores the original positional relationship (an arrow in FIG. 6B). It has a function to generate.

With this fall prevention structure 102, as in the fall prevention structure 100 of the first embodiment and the fall prevention structure 101 of the second embodiment, a part of the moving energy of the bridge girder 20 is partly transferred by the bridge girder 20 to the inclined surface 61 of the bridge girder restoring member 60. The movement energy of the bridge girder 20 is consumed so as to convert the energy into a rushing energy, so that the movement of the bridge girder 20 integrated with the triangular columnar member 22 can be regulated so as not to slide too much.
In addition, the bridge girder 20 does not slide too much by the gravity acting on the bridge girder 20 that has been pushed up along the inclined surface 61 of the bridge girder restoring member 60 so as to pull down the bridge girder 20 along the inclined surface 61. Thus, the bridge girder 20 integrated with the triangular prism-shaped member 22 can be prevented from falling from the support structure 10.
Then, after the earthquake has ceased, the bridge girder 20 integrated with the triangular prism-shaped member 22 can be restored to a predetermined arrangement on the support structure 10, so that restoration work for returning the shifted bridge girder 20 to a predetermined position is possible. It becomes unnecessary and can reduce the maintenance work after the earthquake.

The present invention is not limited to the above embodiment.
For example, as shown in FIG. 7, a bridge girder restoring member 60 having a substantially W-shaped upper surface side on which a pair of inclined surfaces 61 are formed when viewed from the front is attached to the inclined surface 61 and viewed from the front. The bridge-falling prevention structure 101 may include a plate-like member 41 having a substantially W shape and a bridge girder 21 having a lower surface that has a substantially W shape when viewed from the front.
Further, for example, as shown in FIG. 8, the bridge girder restoring member 60 in which the upper surface provided with the pair of inclined surfaces 61 is formed in a concave R surface and the same curvature as the inclined surface 61 are formed. Even if it is the falling bridge prevention structure 101 of the structure provided with the plate-shaped member 41 stuck on the inclined surface 61, and the bridge girder 21 which has the lower surface formed in the convex R surface which is the same curvature as the inclined surface 61. Good. The center of gravity of the bridge girder 21 is preferably lower than the center of rotation of the bridge girder 21 that swings along the concave inclined surface 61.
Such a falling bridge prevention structure 101 can also prevent the bridge girder 21 from falling over the support structure 10. In addition, since the bridge girder 21 can be restored to the predetermined arrangement on the support structure 10 after the earthquake has ceased, no restoration work is required to return the shifted bridge girder 21 to the predetermined position. Maintenance work can be reduced.

In addition, in the above embodiment, although the case where the plate-shaped member 41 which has smoothness was provided in the inclined surface 61 of the bridge girder restoring member 60 was demonstrated to an example, this invention is not limited to this, For example, the plate-like member 41 may be provided on the bridge girder-side inclined surface 21 a of the bridge girder 20 facing the inclined surface 61 (or the bridge-girder-side inclined surface 22 a of the triangular columnar member 22), and the inclined surface 61 of the bridge girder restoring member 60. The plate-like member 41 may be provided on both the bridge girder-side inclined surface 21a of the bridge girder 20 (or the bridge-girder-side inclined surface 22a of the triangular columnar member 22).
When the plate member 41 is not used, the frictional resistance of the inclined surface 61 of the bridge girder restoring member 60 and the bridge girder side inclined surface 21a of the bridge girder 20 (or the bridge girder side inclined surface 22a of the triangular columnar member 22) is reduced. It is preferable to apply a known surface treatment such as fluorine coating.

  In addition, it is needless to say that other specific detailed structures can be appropriately changed.

100, 101, 102 Falling bridge prevention structure 10 Support structure 20, 21 Bridge girder 21a Bridge girder side inclined surface 22 Triangular prism-shaped member 22a Bridge girder side inclined surface 30, 60 Bridge girder restoring member 31, 61 Inclined surface 40, 41 Plate member 50 沓

Claims (5)

A falling bridge prevention structure for preventing the bridge girder installed on the support structure from falling,
When the bridge girder slides in a direction intersecting with the extending direction, and the positional relation between the bridge girder and the support structure is shifted, the positional relation between the bridge girder and the support structure is caused by the weight of the bridge girder. A bridge girder prevention structure characterized in that a bridge girder restoring member formed with an inclined surface for generating a restoring force to restore the original is disposed on the support structure.   The bridge girder restoring member is disposed so that at least a part of the inclined surface forms a pair with the bridge girder interposed therebetween, and the inclined surfaces forming the pair have inclinations that descend toward each other. The falling bridge prevention structure according to claim 1.   The bridge girder-side inclined surface having the same inclination angle as the inclined surface is formed on the lower surface of the bridge girder that is installed on the bridge girder restoring member and faces the inclined surface. The structure for preventing falling bridges as described in 1.   4. The falling bridge prevention structure according to claim 3, wherein a plate member having smoothness is provided on at least one of the inclined surface and the bridge girder-side inclined surface.   The fallen bridge prevention structure according to claim 1 or 2, wherein a plate member having smoothness is provided on the inclined surface.

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