JP2017141564A - Bridge girder snow prevention structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To protect a supporting part of a bridge pier and prevent a bridge girder from being lifted out of the bridge pier, even if there is a large quantity of snow cover on the bridge sidewalk of the bridge girder.SOLUTION: A bridge sidewalk 15 of a bridge girder 12 installed through supporting parts 11 (11A, 11B) on a bridge pier 10 includes: a floor board material 16 horizontally provided in the upper side of the bridge girder 12 and enabling walking on the upper surface; and an arm material 17 diagonally provided between the tip side of the floor board material 16 and the lower side of the bridge girder 12 positioned below the floor board material 16, and supporting the floor board material 16 from the lower part. The floor board material 16 is rotatably provided centering on a first horizontal axis 20 between a proximal end portion and the bridge girder 12. The arm material 17 has each connection part of the tip side of the floor board material 16 and the lower side of the bridge girder 12 provided centering on second and third horizontal axes 21, 22, respectively, and has a damper 23 (length adjustment means) in which a distance L between the connection parts can be changed according to a load applied on the floor board material 16.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a bridge girder snow prevention structure capable of preventing a bridge girder from lifting up from a pier even when a large amount of snow is on a bridge sidewalk of the bridge girder.

The bridge girder installed on the pier is equipped with a bridge sidewalk for inspection, and a large amount of snow may accumulate on the bridge sidewalk in winter.
For example, as shown in Non-Patent Document 1 below, on March 13, 2014, on the Kitakami Line / Oarasawa Bridge Girder, which is a railway line of East Japan Railway (JR East), the weight of snow that fell on the bridge sidewalk As a result, the bridge girder is lifted off the pier.

More specifically, as shown in FIGS. 4A and 4B, a general bridge girder 1 is installed on a concrete pier 2 via support portions 3 (3 </ b> A and 3 </ b> B). The support portions 3 are provided at regular intervals along the width direction of the rail R, and the support portions 3 (3A) on one side support the leg portions 1A of the bridge girder 1; And the leg part 1B of the bridge girder 1 is supported by the support part 3 (3B) of the other side.
In addition, a bridge sidewalk 4 is provided in such a bridge girder 1, and a worker is allowed to pass through the bridge sidewalk 4 or a bridge girder is checked by the worker.

"Deformation caused by snow load and its countermeasures on Kitakami Line" Katsuho Sasaki, Yasuhiro Fujita, Atsushi Yamaguchi: Structural engineering data (45), 38-41, 2015-05 Published by Structural Engineering Center, East Japan Railway Company

  In the bridge girder 1 configured as described above, as shown in FIGS. 5A and 5B, when a large amount of snow (indicated by the symbol S) has accumulated on the side bridge 4 installed on the side. In this case, a falling moment occurs around the support 3 (3A) located on the side of the bridge girder 1 (indicated by an arrow M), and the outer support 3 (3B) tries to lift from the pier 2 (Indicated by arrow F). Further, the lift generated here is indicated by a symbol f.

In the bridge girder 1 as described above, as shown in FIG. 5B, the leg portion 1B is supported in order to prevent the leg portion 1B of the pier 2 from being lifted due to the occurrence of the overturning moment M. Measures have been taken such as driving anchor bolts 5 into the outer support 3 (3B).
However, in the bridge girder 1 described above, when an excessive fall moment M is applied to the pier 2 due to a large amount of snow exceeding prediction, deformation such as bending of the anchor bolt 5 occurs, and a new safety measure is expected. It was.

  The present invention has been made in view of the above-described circumstances, and even when there is a large amount of snow on the bridge sidewalk of the bridge girder, the bridge girder is protected and the bridge girder is surely lifted from the pier. Provide a structure to prevent snow accumulation on bridge girders.

In order to solve the above problems, the present invention proposes the following means.
The present invention is a bridge girder snow cover prevention structure provided on a bridge girder side bridge of a bridge girder installed on a bridge pier via a support part, the bridge side pavement connected to the side of the bridge girder in a tiltable manner, and the bridge And a support mechanism for supporting the floorboard material of the sidewalk in a horizontal posture until a predetermined load is exceeded.
More specifically, it is a bridge girder snow-prevention structure provided on a bridge sidewalk of a bridge girder installed on a bridge pier via a support part, and the bridge sidewalk is provided horizontally on the upper side of the bridge girder. A floor board material that can be walked on the upper surface thereof, and is provided obliquely between a tip side of the floor board material and a lower side portion of the bridge girder located below the floor board material, and the floor board material is viewed from below. And supporting the arm material, the floor board material is provided rotatably about a first horizontal axis between the base end portion and the bridge girder, the arm material, The connecting portions on the front end side and the lower side portion of the bridge girder are provided so as to be rotatable about the second and third horizontal axes, respectively, and the distance between these connecting portions depends on the load applied to the floor board material. It has a length adjusting means that can be changed.

According to said structure, when the load more than predetermined is added to the bridge sidewalk, the accumulated snow can be excluded by inclining the said floor board material.
Specifically, since the arm member is provided with length adjusting means that can change the distance between the connecting portions on the front end side of the floor board material and the lower side part of the bridge girder according to the load applied to the floor board material, When there is a large amount of snow on the floor board material and a great load is applied to the floor board material, the length of the arm material is reduced by the length adjusting means.
At this time, the length of the arm material is reduced by the length adjusting means while the floor board material and the arm material rotate around the first to third horizontal axes in the respective connecting portions, The angle of the supported floorboard material can be changed from the horizontal position to the inclined position.
As a result, in the present invention, when a large amount of snow is generated on the floor board material, the angle of the floor board material supported by the arm material can be changed from the horizontal position to the inclined position, so that a large amount of the piled material on the floor board material can be obtained. Snow can be dropped, and the bridge girder can be prevented from being lifted from the pier, thereby improving the safety of the bridge girder.

  In the invention, it is preferable that the length adjusting means is composed of a damper that reduces when a load of a certain value or more is applied to the floor board material.

According to the above configuration, the length of the arm material is reduced by the damper that is reduced when a load of a certain value or more is applied to the material, so that the floor board material supported by the arm material is removed from the horizontal position. The angle can be changed to be an inclined position.
As a result, when a large amount of snow is generated on the floor board material, the angle of the floor board material supported by the arm material is changed from the horizontal position to the inclined position, and a large amount of snow accumulated on the floor board material is dropped. As a result, it is possible to prevent the bridge girder from lifting up from the pier and to increase the safety of the bridge girder.

  In the invention, it is preferable that the damper is a pneumatic damper that is reduced when a load of a certain value or more is applied to the floor board material.

  According to the above configuration, it is necessary to add a special valve mechanism for controlling the flow of the internal fluid by using a pneumatic damper that reduces when a load of a certain value or more is applied to the floor board material. The overall configuration can be simplified.

  In the invention, it is preferable that the length adjusting means includes a pair of link members constituting the arm member, and a horizontal shaft provided at a connecting portion of the pair of link members and rotatably supporting the link member. The connecting pin has a torque limiter that allows rotation of the link material when a rotational torque of a certain value or more is applied to the connection portion of the link material via the floor board material. And

According to said structure, it was set as the structure which has a torque limiter which permits rotation of this link material, when the rotational torque more than a fixed value is applied to the connection part of a pair of link material. Thereby, when a load is applied on the floor board material due to a large amount of snow and a rotational torque of a certain value or more is applied to the connecting portion of the link material constituting the arm material, the link material is allowed to rotate. .
As a result, in the present invention, when a large amount of snow is generated on the floor board material, the angle of the floor board material supported by the arm material can be changed from the horizontal position to the inclined position, and a large amount of snow accumulated on the floor board material. Can be dropped, the bridge girder can be prevented from rising from the pier, and the safety of the bridge girder can be enhanced.

  In the invention, it is preferable that the length adjusting means includes a pair of link members constituting the arm member, and a horizontal shaft provided at a connecting portion of the pair of link members and rotatably supporting the link member. A pin and a non-rotating piece that is provided at the connecting portion of the link material and holds the link material in a straight line. The anti-rotating piece has a rotational torque of a certain value or more at the connecting portion of the link material. When applied, it is sheared and fractured, allowing the link material to rotate.

According to said structure, when the rotational torque more than a fixed value is applied to the connection part of a pair of link material which comprises an arm material, it is sheared fracture | rupture, and it has the rotation stop piece which accept | permits rotation of this link material did.
As a result, when a load is applied on the floor board material due to a large amount of snow and a rotational torque of a certain value or more is applied to the connecting portion of the link material constituting the arm material, the detent piece is sheared and broken. The link material is allowed to rotate.
As a result, in the present invention, when a large amount of snow is generated on the floor board material, the angle of the floor board material supported by the arm material can be changed from the horizontal position to the inclined position, and a large amount of snow accumulated on the floor board material. Can be dropped, the bridge girder can be prevented from rising from the pier, and the safety of the bridge girder can be enhanced.

  In the present invention, an anchor bolt for preventing the bridge girder from lifting up from the bridge pier is fastened to the support portion.

  According to the above configuration, since the anchor bolt for preventing the bridge girder from lifting up from the pier is fastened to the support part of the bridge girder, the safety of the bridge girder can be further enhanced by using in combination with the length adjusting means described above. Can do.

  In the present invention, the bridge girder includes a sensor for measuring the lift of the bridge girder from the bridge pier, and alarm means for outputting an alarm according to a detection value of the sensor. .

  According to said structure, danger can be alert | reported promptly to the worker who walks the bridge side walk of a bridge girder by referring the alarm from the alarm means based on the detection value in a sensor. And safety of a bridge girder can be further improved by using together with the length adjustment means which mentioned above the danger information by the said alarm.

  According to the present invention, when a large amount of snow is generated on the floor board material, the angle of the floor board material supported by the arm material can be changed from the horizontal position to the inclined position. Therefore, a large amount of snow accumulated on the floor board material As a result, the bridge girder can be prevented from being lifted off the pier, and the safety of the bridge girder can be improved.

It is a figure which shows 1st Embodiment of this invention, Comprising: (A) is a schematic block diagram cut | disconnected in the width direction of a railroad rail, (B) is a figure which shows a support part. It is a figure which shows the length adjustment means which concerns on 2nd Embodiment of this invention, Comprising: (A) is a figure when a snow load is not applied, (B) is a case where a board member inclines with a snow load applied FIG. It is a figure which shows the length adjustment means which concerns on the modification of 2nd Embodiment of this invention, Comprising: (A) is a figure when the snow load is not applied, (B) is a snow load applied, and a board member inclines FIG. It is a figure which concerns on the conventional bridge girder, Comprising: (A) is a figure in case the snow load is not applied, (B) is a figure which shows a support part. It is a figure which concerns on the conventional bridge girder, Comprising: (A) is a figure when a snow load is applied and a board member inclines, (B) is a figure which shows a support part.

(First embodiment)
A first embodiment of the present invention will be described with reference to FIGS. 1 (A) and 1 (B).
A reference numeral 10 in FIG. 1A is a concrete pier, and a bridge girder 12 is installed on the pier 10 through support portions 11 (11A and 11B).
This bridge girder 12 has leg portions 13 (13A and 13B) provided at regular intervals along the width direction of the railroad rail R. These leg portions 13 (13A and 13B) are railroad rails. A plurality of pairs are installed along the length direction of R.
Further, in the leg portions 13 of the bridge girder 12, one leg portion 13A is installed on the concrete bridge girder 12 via a support portion 11A, and the other leg portion 13B is placed on the concrete bridge girder 12 via the support portion 11B. Installed.

Further, a bridge sidewalk 15 is provided on the leg portion 13A located on one side of the bridge girder 12 so that a worker can pass through the bridge sidewalk 15 or a bridge girder can be inspected by the worker. It has become.
The bridge sidewalk 15 is provided horizontally (in the normal position) on the upper side of the bridge girder 12 and is capable of walking on the upper surface thereof, and the front end side of the floor board material 16 and the floor board material 16. And an arm member 17 which is provided obliquely between the lower side portion of the bridge girder 12 located below and supports the floor board material 16 from below.

As shown in FIG. 1B, anchor bolts 14 are provided on the support portion 11B located on the other leg portion 13B of the bridge girder 12.
This anchor bolt 14 penetrates the support portion 11B of the bridge girder 12 and is screwed to the pier 10 so as to prevent the other leg portion 13B constituting the bridge girder 12 from being lifted. The leg portion 13B is firmly fixed on the pier 10.

Next, the bridge girder snow cover prevention structure 100 installed between the bridge sidewalk 15 and the bridge girder 12 will be described.
The floor board 16 is provided so as to be rotatable about a first horizontal shaft 20 at a connecting portion between the base end portion and the bridge girder 12, and is usually in a horizontal position shown in FIG. Is arranged. The first horizontal shaft 20 of the floor member 15 is disposed on the upper side of the leg portion 13A of the bridge girder 12.

The arm member 17 is provided with a connecting portion at each end located on the front end side of the floor board material 16 and the lower side portion of the bridge girder 12 so as to be rotatable about the second horizontal shaft 21 and the third horizontal shaft 22, respectively. In the middle of the arm member 17, a damper 23 serving as a length adjusting means is provided.
The damper 23 is reduced when a load of a certain value or more is applied to the floor board material 16, and the distance L between the connecting portions where the second horizontal shaft 21 and the third horizontal axis 22 are provided is determined as the floor board material. It changes according to the load concerning 16. For example, the damper 23 is set to be reduced when a weight of 1 ton or more per square meter is applied to the floor board material 16 immediately above, and is set to be a safety design that does not reduce when a normal worker walks.
When such a setting causes a large amount of snow on the floor board material 16 (for example, snow of 1 ton or more per square meter on the floor board material 16 directly above), the damper 23 is reduced and the arm is reduced. The floor board material 16 supported by the material 17 can be rotated in the direction of arrow a to change the angle of the floor board material 16 from a horizontal position to an inclined position.
As a result, a large amount of snow accumulated on the floor board material 16 can be slid and dropped on the surface of the inclined floor board material 16, and as a result, the bridge girder 12 is lifted from the bridge pier 10. The bridge girder leg portion 13B located on the opposite side can be prevented from being lifted, and the safety of the bridge girder 12 can be enhanced.

  In addition, although an air damper is used as the damper 23, it is not limited to this, You may use the hydraulic damper etc. which can supply hydraulic pressure via an electromagnetic valve from the outside. In addition, by using a hydraulic type damper as the damper 23, the damper 23 may be extended by appropriately switching the electromagnetic valve and the switching valve, and the inclined floor board material 16 may be restored to be horizontal. .

Further, as shown in FIG. 1B, the bridge girder 12 is a displacement gauge that detects the lifting of the leg portion 13B of the bridge girder 12 from the pier 10 or a strain gauge that detects distortion of the floor board material or the damper. And a warning means 31 that outputs an alarm according to a detection value of the sensor 30. Here, as the alarm means 31, a speaker that outputs an alarm sound, an LED display plate that displays an alarm, or the like is used.
Then, by hearing the alarm from the warning means 31, it is possible to promptly notify the worker walking the bridge sidewalk 15 of the bridge girder 12. Further, the detected value of the sensor 30 may be used to open and close the solenoid valve when a hydraulic damper is used.

As described above in detail, according to the bridge girder snow-prevention structure 100 shown in the present embodiment, the arm member 17 is provided with the distance L between the connecting portions on the front end side of the floor board material 16 and the lower side portion of the bridge girder 12. Since the damper 23 that can be changed according to the load applied to the floor board material 16 is installed, when there is a large amount of snow on the floor board material 16 and a great load is applied to the floor board material 16, the damper 23 Thus, the length of the arm material 17 is reduced.
At this time, the floor material 16 and the arm material 17 are rotated around the first to third horizontal shafts 20 to 22 in the respective connecting portions, and the length of the arm material 17 is reduced by the damper 23. The angle of the floor board material 16 supported by the arm material 17 can be changed from the horizontal position to the inclined position.
That is, in the bridge girder snow accumulation prevention structure 100 shown in the present embodiment, when a large amount of snow is generated on the floor board material 16, the angle of the floor board material 16 supported by the arm material 17 is changed from the horizontal position to the inclined position. Therefore, a large amount of snow accumulated on the floor board material 16 can be dropped, and as a result, the bridge girder 12 can be prevented from lifting from the bridge pier 10 and the safety of the bridge girder 12 can be improved.

  In addition, in the bridge girder snow prevention structure 100 shown in the present embodiment, anchor bolts 14 that prevent the bridge girder 12 from lifting from the bridge pier 10 are fastened to the support portion 11B located on the opposite side of the floor board material 16. The safety of the bridge girder 12 can be further enhanced by using the damper 23 together.

  In the bridge girder snow prevention structure 100 shown in the present embodiment, the sensor 30 that measures the lifting of the bridge girder 12 from the pier 10 and the alarm means 31 that outputs an alarm according to the detection value of the sensor 30 are provided. Furthermore, the danger can be quickly notified to the worker who walks on the bridge sidewalk 15 of the bridge girder 12 by providing. And it becomes possible to further raise the safety | security of the bridge girder 12 by using the danger alert | report by the said alarm together with the damper 23 mentioned above.

(Second Embodiment)
A second embodiment of the present invention will be described with reference to FIGS. 2 (A) and 2 (B) and FIGS. 3 (A) and 3 (B).
The bridge girder snow prevention structure 101 shown in the second embodiment is different from the bridge girder snow prevention structure 100 shown in the first embodiment in the configuration of the length adjusting means.
That is, in the bridge girder snow prevention structure 100 of the first embodiment, the length adjusting means is configured by the damper 23. However, the bridge girder snow prevention structure 101 of the second embodiment is shown in FIGS. 2 (A) and (B). As shown, the length adjusting means 40 is connected to a pair of link members 42 forming the arm member 41 and a horizontal shaft that is provided at a connecting portion of the pair of link members 42 and rotatably supports the link member 42. And a connecting pin 43.
Here, as the connecting pin 43, when a rotational torque of a certain value or more is applied to the connection portion of the link material 42 via the floor board material 16 (for example, the floor board material 16 directly above has a weight of 1 ton or more per square meter. In this case, a rotating shaft 43B having a torque limiter 43A that allows the link member 42 to rotate by releasing the internal engagement is employed.
The torque limiter 43A is configured such that a coil spring for tightening the outer diameter surface is attached to an inner ring coaxial with a rotating shaft 43B that is rotatably inserted inside the outer ring member, and tries to rotate the link member 42. If the torque is below a certain value, the inner ring will not rotate due to the binding force of the coil spring, and if the torque applied to the inner ring exceeds a certain value (when excessive fall torque occurs due to snow), the binding force of the coil spring The inner ring rotates due to the decrease in.

  As a result, in the bridge girder snow prevention structure 101 according to the present embodiment, the connection pin 43 having the torque limiter 43A is employed on the connecting portion of the arm member 41 including the pair of link members 42, so that When a large amount of snow is generated, the angle of the floor board material 16 supported by the arm material 17 can be changed from the horizontal position to the inclined position (see FIGS. 2A to 2B).

A large amount of snow piled on the floor board material 16 can be dropped by the inclination of the floor board material 16 as described above, and the bridge girder from the bridge pier 10 can be prevented from being lifted, thereby improving the safety of the bridge girder 12. Is possible.
2A to 2B, reference numeral 44 denotes a stopper that holds the arm member 41 formed of a pair of link members 42 in a horizontal position and restricts the upward rotation.

Further, in the bridge girder snow accumulation prevention structure 101 shown in the second embodiment, instead of the length adjusting means 40 using the torque limiter 43A, as shown in FIGS. 3 (A) and 3 (B), the restricting means and The length adjusting means 50 using the rotation stopper piece may be used.
The length adjusting means 50 includes a pair of link members 52 forming the arm member 51 and a connecting pin comprising a horizontal shaft that is provided at a connecting portion between the pair of link members 52 and rotatably supports the link member 52. 53 and a detent piece 54 that is positioned below the connecting portion of the link member 52 and holds the link member 52 in a straight line.
As shown in FIGS. 3 (A) to 3 (B), the rotation stop piece 54 is sheared and broken when a rotational torque of a certain value or more is applied to the connecting portion of the link member 52, and the link member 52 Rotation is allowed.

In the length adjusting means 50 configured as described above, a load is applied on the floor board material 16 due to a large amount of snow accumulation, and the connection portion of the link material 52 constituting the arm material 17 rotates more than a certain value. When torque is applied, the rotation stop piece 54 is sheared and broken, and the link member 52 is allowed to rotate.
As a result, when a large amount of snow is generated on the floor board material 16, the angle of the floor board material 16 supported by the arm material 17 can be changed from the horizontal position to the inclined position (FIG. 3A). (See FIG. 3B), a large amount of snow piled on the floor board material 16 can be dropped, and the bridge girder 12 can be prevented from floating from the bridge pier 10 and the safety of the bridge girder 12 can be improved. .

  As mentioned above, although embodiment of this invention was explained in full detail with reference to drawings, the concrete structure is not restricted to this embodiment, The design change etc. of the range which does not deviate from the summary of this invention are included.

  The present invention relates to a bridge girder snow prevention structure capable of preventing a bridge girder from lifting up from a pier even when a large amount of snow is on a bridge sidewalk of the bridge girder.

10 Bridge Pier 11 (11A / 11B) Bearing 12 Bridge Girder 13 (13A / 13B) Leg 14 Anchor Bolt 15 Bridge Sidewalk 16 Floor Board Material 17 Arm Material 20 First Horizontal Axis 21 Second Horizontal Axis 22 Third Horizontal Axis 23 Damper DESCRIPTION OF SYMBOLS 30 Sensor 31 Alarm means 40 Length adjustment means 41 Arm material 42 Link material 43 Connection pin 50 Length adjustment means 51 Arm material 52 Link material 53 Connection pin 54 Non-rotation piece 100 Bridge girder snow prevention structure 101 Bridge girder snow prevention structure

Claims (8)

Bridge girder snow prevention structure provided on the bridge sidewalk of the bridge girder installed on the pier via the support,
A bridge sidewalk connected to the side of the bridge girder in a tiltable manner;
A support mechanism that supports the floorboard material of the bridge sidewalk in a horizontal posture until a predetermined load is exceeded;
A bridge girder snow-preventing structure characterized by comprising: The bridge sidewalk is a floor board material that is horizontally provided on the upper side of the bridge girder and is capable of walking on the upper surface thereof, and a lower side of the bridge girder that is located at the front end side of the floor board material and below the floor board material. An arm member that is provided obliquely with respect to the portion and supports the floor board material from below,
The floor board material is provided so as to be rotatable around a first horizontal axis between the base end portion and the bridge girder,
The arm material is provided such that each of the connecting portions on the front end side of the floor board material and the lower side portion of the bridge girder is rotatable about the second and third horizontal axes, respectively, and the distance between these connecting portions is The bridge girder snow-preventing structure according to claim 1, further comprising length adjusting means that can be changed according to a load applied to the floor board material.   The bridge girder snow-preventing structure according to claim 2, wherein the length adjusting means includes a damper that reduces when a load of a certain value or more is applied to the floor board material.   The bridge girder snow-preventing structure according to claim 3, wherein the damper is a pneumatic damper that reduces when a load of a certain value or more is applied to the floor board material. The length adjusting means has a pair of link members constituting the arm member, and a connecting pin made of a horizontal shaft that is provided at a connection portion between the pair of link members and rotatably supports the link member,
The connection pin includes a torque limiter that allows rotation of the link material when a torque greater than a certain value is applied to the connection portion of the link material via the floor board material. Bridge girder snow prevention structure described in 1. The length adjusting means includes a pair of link members constituting the arm member, a connecting pin including a horizontal shaft provided at a connection portion between the pair of link members and rotatably supporting the link member, and the link member A rotation stopper piece that is provided in the connecting portion and holds the link material in a straight line,
3. The bridge girder snow according to claim 2, wherein the detent piece is sheared and fractured when rotation torque of a predetermined value or more is applied to the connection portion of the link material to allow rotation of the link material. Prevention structure.   The bridge girder snow prevention structure according to any one of claims 1 to 6, wherein an anchor bolt for preventing the bridge girder from lifting up from the bridge pier is fastened to the support portion.   The said bridge girder is equipped with the sensor which measures the lift of the said bridge girder from the said bridge pier, and the alarm means which outputs an alarm according to the detected value of this sensor, It is characterized by the above-mentioned. Bridge girder snow cover prevention structure.

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