JP2015068153A - Expansion device for bridge - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an expansion device for a bridge, endurable against large impact force, being high in water cutoff performance, hardly deteriorating, and capable of damping horizontal force in an earthquake.SOLUTION: An expansion device 30 for a bridge comprises: a face plate 31 installed in an upper part of an expansion spacing Y2 formed between bridge girders 10 and 20, mounted to a notch part 24 of the bridge girder 20 and extending horizontally; and a cover plate 33 mounted to a notch part 14 of the bridge girder 10 and extending horizontally. The face plate 31 is formed in a single thick plate shape, and straddles the expansion spacing Y2, and is arranged in a state of forming an expansion clearance S1 between its end surface 31a and an end surface of the notch part 14 of the bridge girder 10. The cover plate 33 is arranged on the upper side of a tip part 31b of the face plate 31 so as to straddle the expansion clearance S1. In this expansion device 30 for a bridge, a hydraulic damper 32 expandable in the bridge axial direction is interposed between the end surface 31a of the face plate 31 and the end surface of the notch part 14 of the bridge girder 10.

Description

  TECHNICAL FIELD The present invention relates to a bridge extension device installed at an upper part of a play, and more particularly to a bridge extension device that can withstand a large impact force and has high water-stopping performance and hardly deteriorates.

  A gap is formed between the abutment and the bridge girder or between the bridge girders. This gap is a gap for absorbing the displacement due to the temperature change of the bridge girder. That is, since the bridge girder expands when the temperature rises and shrinks when the temperature falls, a gap is formed so that the bridge girder can be smoothly expanded and contracted by the temperature change. In the upper part of the gap, a bridge telescopic device is installed in order to secure the passage of vehicles, people, etc. while absorbing the displacement due to the temperature change of the bridge girder.

  As a bridge expansion and contraction device, for example, there is one described in Patent Document 1 below. As shown in FIG. 5, this bridge extension / contraction device is installed, for example, on the upper part of the gap Y formed between the abutment 102 and the bridge girder 110, and faces the bridge axis direction as shown in FIGS. 6 and 7. A pair of face plates 131A and 131B is provided. Each of the face plates 131A and 131B has an upper surface that is substantially the same plane as the paved roads 113 and 123, and is made of steel and has a comb shape. The finger portion 131a of the one face plate 131A extends toward the recess 131b of the other face plate 131B. Thus, a gap T1 is formed between the finger portion 131a and the recess 131b to absorb the displacement due to the temperature change of the bridge girder 110.

  And in the expansion-contraction apparatus 130 for bridges, as shown in FIG. 7, the water stop structure is given to the lower side. In this water stop structure, the sealing material 133 is joined between the abdominal plates 132 just below the face plates 131A and 131B, and the backup material 134 is attached between the abdominal plates 132 just below the sealing material 133. It has been. The sealing material 133 is an elastic member that follows the expansion and contraction of the bridge girder 110 and has high water stopping performance. The backup material 134 prevents the sealing material 133 from leaking downward when the sealing material 133 is filled, and prevents the sealing material 133 from buckling or dropping. Although not shown, a rubber packing is attached to the lower side of the backup material 134 for the purpose of secondary water stop. Thus, even if water or the like enters from the gap T1 between the face plates 131A and 131B, the water stop structure prevents entry into the lower part of the gap Y.

JP 2012-246600 A

  However, the bridge expansion and contraction device 130 described in Patent Document 1 has the following problems. That is, since the traveling vehicle is directly mounted on the bridge expansion / contraction device 130, a large impact force due to traveling of the vehicle acts as shown in FIG. In particular, when the vehicle rides on a step or the like on the road surface, a very large impact force acts on the bridge expansion / contraction device 130. At this time, as shown in FIG. 7, since the finger part 131a is in a cantilever state, it is easily damaged. And since a large impact force is repeatedly received, repeatedly absorbing the displacement by the temperature change of the bridge girder 110 for many years, deterioration and damage become intense. Thus, a bridge expansion and contraction device that can withstand a large impact force has been demanded.

  Furthermore, as described above, when the bridge expansion / contraction device 130 is severely deteriorated and damaged, as shown by a two-dot chain line in FIG. 7, the seal material 133 and the backup material 134 are cracked to form the water leakage path RK. . As a result, earth and sand or rainwater flows down from the water leakage path RK toward the lower part of the gap Y, and accumulates in the narrow part K1 formed below the end part 110a of the bridge girder 110 as shown in FIG. In this narrow part K1, since it is a closed space and poorly ventilated, it becomes wet, and there is a possibility that the end part 110a of the bridge girder 110 and the support 104 are corroded and damaged by the accumulated earth and sand and rainwater. Thus, there has been a demand for a telescopic device for bridges that has high water stopping performance and is unlikely to deteriorate.

  By the way, after the Hyogoken-Nanbu Earthquake, in the bearing 104 that supports the end portion 110a of the bridge girder 110, the steel bearing that has been conventionally used is changed to a rubber bearing for seismic isolation that can attenuate the horizontal force during the earthquake. It is recommended to replace it. However, since the seismic isolation rubber bearings are expensive, there is a fact that the bridge from the steel support to the seismic isolation rubber bearings has not progressed so much in the low traffic volume managed by the local government. On the other hand, in the current state of the expansion and contraction device for bridges, in order to cope with deterioration and damage, repair is generally performed in about 10 years and replaced in about 15 to 20 years. Therefore, as a preventive maintenance measure against a major earthquake, it was examined whether the horizontal force at the time of earthquake could be attenuated by a new bridge expansion / contraction device without replacing with a rubber bearing for seismic isolation.

  In view of the above, the present invention provides a telescopic device for a bridge that can withstand a large impact force, has a high water-stopping performance, is not easily deteriorated, and can attenuate a horizontal force during an earthquake. Objective.

  The expansion device for a bridge according to the present invention is provided between a bridge structure such as an abutment or a bridge girder that is formed between the abutment and the bridge girder or between the girder and facing each other at the upper part between the abutments. A face plate attached to the opposing bridge structure and extending horizontally, and a cover plate attached to the opposing bridge structure and extending horizontally, the face plate Is a single thick plate that straddles the gap and is arranged in a state where an expansion and contraction gap is formed between the end surface and the bridge structure on the other side, and the cover plate is The damper is disposed above the face plate across the expansion gap, and is provided with a damper that is interposed between an end surface of the face plate and the bridge structure on the other side and can expand and contract in the bridge axis direction. The And butterflies.

  According to the bridge extension / contraction device according to the present invention, the face plate has a single thick plate shape, and therefore can withstand a large impact force caused by the running of the vehicle. In addition, since the face plate is disposed across the gap, earth and sand and rain water are unlikely to flow down toward the lower part of the gap, and the water stop performance is difficult to deteriorate. And, the damper can absorb the displacement due to the temperature change of the bridge girder while extending and contracting slightly in the direction of the bridge axis, and for the horizontal force at the time of earthquake, the damper expands and contracts greatly while demonstrating the damping force. Yes.

Further, in the bridge extension / contraction device according to the present invention, the damper includes a cylinder tube contacting one of the end surface of the face plate and the other side bridge structure, and the other end of the end surface of the face plate and the other side bridge structure. It is preferable that the hydraulic damper has a cylinder rod in contact with the cylinder.
In this case, a very slow movement due to a temperature change of the bridge girder can be handled by the cylinder rod following the movement. On the other hand, the rapid movement of the bridge girder during an earthquake can be dealt with by exhibiting a sufficient damping force (resistance force) from the flow of hydraulic oil due to the large movement of the cylinder rod. Thus, if it is a hydraulic damper, it will be easy to cope with both the displacement by the temperature change of a bridge girder, and the horizontal force at the time of an earthquake.

Further, in the bridge extension / contraction device according to the present invention, the damper may be arranged so as to be slightly inclined from the bridge axis direction to the bridge width direction so that the damper can extend and contract in the bridge axis direction and the bridge width direction.
In this case, of the displacement due to the temperature change of the bridge girder, not only the displacement in the bridge axis direction but also the displacement in the bridge width direction, the damper can be slightly expanded and contracted and absorbed.

Further, in the bridge extension / contraction device according to the present invention, the face plate, the cover plate, the damper, a plate support member that supports the face plate, and a damper support member that supports the damper have a substantially rectangular parallelepiped shape. It is good to be an integrated unit.
In this case, for example, when the bridge expansion / contraction device is replaced with an existing bridge expansion / contraction device, the bridge expansion / contraction device is an integral unit having a substantially rectangular parallelepiped shape, which makes it easy to install.

  According to the bridge expansion and contraction device according to the present invention, it is possible to withstand a large impact force, the waterproof performance is high and hardly deteriorates, and the horizontal force can be attenuated during an earthquake.

It is the figure which showed the bridge 1 to which the expansion-contraction apparatus for bridges of 1st Embodiment was applied. It is the figure which expanded the X1 part of FIG. It is the perspective view which showed the expansion-contraction apparatus for bridges of 1st Embodiment. It is the perspective view which showed the expansion-contraction apparatus for bridges of 2nd Embodiment. It is the figure which showed the state in which the expansion-contraction apparatus for bridges was installed in the play between an abutment and a bridge girder. It is the top view which showed the conventional expansion-contraction apparatus for bridges. It is sectional drawing along the ZZ line of FIG.

  Embodiments of a bridge extension / contraction device according to the present invention will be described below with reference to the drawings. FIG. 1 is a view showing bridges 1 and 1A to which the bridge expansion and contraction device 30 of the first embodiment is applied. As shown in FIG. 1, in the bridge 1, a bridge girder 10 extending in the bridge axis direction (left and right direction in FIG. 1) is bridged between the abutment 2 and the pier 3. In the bridge girder 10, one end 10 a is supported on the bridge seat 2 a of the abutment 2 via the movable support 4, and the other end 10 b is supported on the pier 3 via the fixed support 5. Between the parapet 2 b of the abutment 2 and the bridge girder 10, a gap Y <b> 1 that absorbs a displacement due to a temperature change of the bridge girder 10 is formed. A bridge expansion / contraction device 30 is installed between the bridge girder 10 and the parapet 2b of the abutment 2 that are opposed to each other at the upper portion of the gap Y1.

  Further, also in the bridge 1A adjacent to the bridge 1, one end portion 20a of the bridge girder 20 is supported via the movable support 6, and between the bridge girder 20 and the bridge girder 10, a gap that absorbs the displacement due to the temperature change of the bridge girder 20 and 10 is absorbed. Y2 is formed. The length of the bridge in the direction of the bridge axis is appropriately set according to the size of the bridge, but the gap Y2 in this embodiment is about 400 mm. And the expansion-contraction apparatus 30 for bridges is installed between the bridge girders 20 and 10 which oppose on the upper part of the gap Y2. Since the bridge telescopic device 30 installed in the gap Y2 and the bridge telescopic device 30 installed in the gap Y1 have the same configuration, the bridge telescopic device 30 installed in the gap Y2 will be described as a representative. Here, FIG. 2 is an enlarged cross-sectional view of a portion X1 in FIG.

  As shown in FIG. 2, in the bridge girder 10 and the bridge girder 20, the floor slabs 12 and 22 are arranged on the flanges 11 a and 21 a of the main girders 11 and 21 extending in the bridge axis direction, and the floor slabs 12 and 22 are paved. Paths 13 and 23 are formed. And the notch part 14 notched inward (right side of FIG. 2) from the end surface 10c of the bridge girder 10 is formed in the edge part of the floor slab 12 and the paved road 13, and the edge part of the floor slab 22 and the paved road 23 is formed. Is formed with a notch 24 that is notched inwardly (from the left side in FIG. 2) from the end face 20b of the bridge girder 20. The notches 14 and 24 are provided for installing the bridge expansion and contraction device 30 and each have a substantially rectangular parallelepiped space.

  The bridge expansion and contraction device 30 is for securing the passage of vehicles, people and the like while absorbing the displacement due to the temperature change of the bridge girders 20 and 10, and is installed in the upper part of the gap Y2. As shown in FIG. 2, the bridge expansion and contraction device 30 is disposed so as to be fitted into the notches 14 and 24, and the upper surface thereof is substantially the same plane as the paved roads 13 and 23.

  By the way, since the traveling vehicle is directly mounted on the bridge expansion and contraction device 30, a large impact force due to the traveling of the vehicle acts. In particular, when a vehicle rides on a road step or the like, a very large impact force acts on the bridge expansion / contraction device 30. Moreover, if earth and sand or rainwater leaks from the bridge expansion / contraction device 30 and flows down toward the lower portion of the play gap Y2, it accumulates in the narrow portion K0 formed below the end portions 10b and 20a of the bridge girders 10 and 20. It will be. In this case, there is a possibility that the end portions 10b and 20a of the bridge girders 10 and 20, the fixed support 5 and the movable support 6 may be corroded by the accumulated earth and sand or rainwater. Thus, there is a demand for a bridge expansion and contraction device that can withstand a large impact force and has high water-stopping performance and is unlikely to deteriorate.

  On the other hand, the bridges 1, 1 </ b> A of the present embodiment are low-traffic bridges managed by local governments, and are not exchanged from steel bearings to seismic isolation rubber bearings. That is, the movable bearings 4 and 6 and the fixed bearing 5 are steel bearings that are generally used from the past, and are not seismic isolation rubber bearings that can attenuate the horizontal force during an earthquake. However, since replacement with a seismic isolation rubber bearing is very costly, it is possible to attenuate the horizontal force during an earthquake as a preventive maintenance measure against a major earthquake without replacement with a seismic isolation rubber bearing. It is desired.

  Therefore, the bridge expansion and contraction device 30 according to the present embodiment is configured so as to be able to withstand a large impact force based on the above-described situation, to have a high water-stopping performance, hardly deteriorate, and to attenuate a horizontal force at the time of an earthquake. ing. Here, FIG. 3 is a perspective view showing the bridge telescopic device 30 of the first embodiment. As shown in FIGS. 2 and 3, the bridge expansion and contraction device 30 includes a face plate 31, a hydraulic damper 32, a cover plate 33, a plate support member 34, and a damper support member 35. The members 31 to 35 are a substantially rectangular parallelepiped shape and are an integral unit. The size of the bridge expansion and contraction device 30 is determined based on the size of the bridge girders 10 and 20, the size of the gap Y2, the damping force to be generated, and the like. The width and thickness can be appropriately changed from those shown in FIG.

  The face plate 31 has a single thick plate shape and is a rectangular parallelepiped steel material extending horizontally. The face plate 31 is supported by a plate support member 34, and the upper surface thereof is substantially the same plane as the paved road 23. The plate support member 34 is a rib or retaining material that improves the strength of the face plate 31 while supporting the face plate 31 from below. As shown in FIG. 2, the face plate 31 extends from the wall surface of the notch portion 24 toward the wall surface of the notch portion 14 facing the bridge plate so as to straddle the gap Y2, and has an end surface 31a. And the wall surface of the notch part 14 are arranged in a state where an expansion / contraction gap S1 is formed. In this way, the upper side of the gap Y2 is completely covered by the single face plate 31, so that earth and sand and rainwater do not flow into the gap Y2.

  The face plate 31 has a base end portion 31c supported by a plate support member 34, a tip end portion 31b supported by a damper support member 35 described later, and a plate thickness of about 100 mm. Thus, the face plate 31 is supported at both ends, and is thicker than the conventional general face plate (thickness of about 25 to 100 mm). It is able to withstand a large impact force from running. The approximate length of each member of the bridge extension / contraction device 30 of the present embodiment will be described. The length of the face plate 31 in the bridge axis direction is about 1000 mm, and the length of the hydraulic damper 32 in the bridge axis direction is about 500 mm. The plate thickness of the cover plate 33 is about 10 mm, the length of the plate support member 34 in the bridge axis direction is about 400 mm, the length of the damper support member 35 in the bridge axis direction is about 700 mm, and the plate support member The vertical length of 34 and the vertical length of the damper support member 35 are about 220 mm. However, each length described above is an example and can be changed as appropriate.

  The hydraulic damper 32 expands and contracts in the direction of the bridge axis, thereby absorbing the displacement due to the temperature change of the bridge girder 20 and absorbing the horizontal force during the earthquake. In the present embodiment, four hydraulic dampers 32 are arranged side by side in the bridge width direction (the direction perpendicular to the bridge axis), and each has the same configuration. Note that the number of hydraulic dampers 32 can be changed as appropriate, and may be a single hydraulic damper integrally connected in the bridge width direction, for example. Each hydraulic damper 32 is supported by a damper support member 35, and is interposed between the end surface 31a of the face plate 31 and the end surface of the notch 14, that is, in the expansion / contraction gap S1. The damper support member 35 is a rib or a retaining material that improves the strength of the hydraulic damper 32 while supporting the hydraulic damper 32 from below. And the damper support member 35 is comprised with the box shape with the steel materials, and the water stop performance is high and it is hard to deteriorate.

  Each hydraulic damper 32 includes a cylinder tube 32 a that is in contact with the wall surface of the notch 14, and a cylinder rod 32 b that is in contact with the end surface 31 a of the face plate 31. The cylinder tube 32a accommodates the proximal end side of the cylinder rod 32b inside, and the distal end side of the cylinder rod 32b is movable in the bridge axis direction with respect to the cylinder tube 32a. The hydraulic damper 32 is disposed coaxially with the bridge axis direction, and the end surface 31a of the face plate 31 is a plane orthogonal to an axis extending in the bridge axis direction. The hydraulic damper 32 is passively operated. When the cylinder rod 32b is pressed and moved into the cylinder tube 32a by an external force, the hydraulic oil in the cylinder tube 32a flows, and according to the pressing force. It is designed to exert a damping force (resistance force).

  The cover plate 33 is for securing passage of vehicles, people, etc. above the expansion / contraction gap S1, is a thin plate, and is a steel material that extends horizontally. The cover plate 33 is supported by each cylinder tube 32 a and the tip end portion 31 b of the face plate 31, and the upper surface thereof is substantially the same plane as the paved road 13. As shown in FIG. 2, the cover plate 33 is disposed so as to extend from the wall surface of the notch 14 in the bridge axis direction. A sealing process is applied to the gap between the front end portion of the cover plate 33 and the front end portion 31b of the face plate 31 so that earth and sand and rainwater do not enter.

  Next, the operation of the bridge telescopic device 30 will be described. When the temperature rises and both the bridge girders 10 and 20 extend, the distance Y2 becomes shorter, the face plate 31 slightly moves toward the right side of FIG. 2, and the cylinder tube 32a of the hydraulic damper 32 is shown in FIG. Move slightly to the left of 2. Thereby, the end surface 31a of the face plate 31 slightly presses the cylinder rod 32b. At this time, the cylinder rod 32b moves slightly to the right in FIG. 2 following the movement of the face plate 31, and can absorb the elongation due to the temperature rise of the bridge beams 10 and 20.

  Further, when the temperature decreases and both the bridge girders 10 and 20 contract, the distance Y2 increases, the face plate 31 moves slightly toward the left side in FIG. 2, and the cylinder tube 32a of the hydraulic damper 32 is provided. Slightly moves to the right in FIG. As a result, the cylinder rod 32b is released from being pressed from the end surface 31a of the face plate 31. At this time, the cylinder rod 32b moves slightly to the left in FIG. 2 following the movement of the face plate 31, and can absorb the shrinkage due to the temperature drop of the bridge beams 10 and 20.

  On the other hand, when a horizontal force acts on the bridge girders 10 and 20 during an earthquake, the hydraulic damper 32 exerts a large damping force. That is, the bridge girder 20 and the face plate 31 greatly move toward the right side of FIG. 2 due to the horizontal force at the time of the earthquake, and the cylinder rod 32b tends to move greatly into the cylinder tube 32a. At this time, a large damping force is exhibited by the flow of the hydraulic oil in the cylinder tube 32a, and the movement of the bridge beam 20 and the face plate 31 can be attenuated.

  Similarly, the bridge girder 10 and the cylinder tube 32a greatly move toward the left side of FIG. 2 due to the horizontal force at the time of the earthquake, and the cylinder rod 32b tends to move greatly into the cylinder tube 32a. At this time, a large damping force is exerted by the flow of hydraulic oil in the cylinder tube 32a, and the movement of the bridge beam 10 and the cylinder tube 32a can be attenuated. Thus, the hydraulic damper 32 can cope with both the displacement due to the temperature change of the bridge girders 10 and 20 and the horizontal force during the earthquake.

  Next, a method for attaching the bridge expansion and contraction device 30 will be described. At present, the expansion and contraction devices for bridges are replaced in about 15 to 20 years in order to cope with deterioration and damage. Therefore, first, the old bridge telescopic device that needs to be replaced is removed. Then, as shown in FIG. 2, a notch 14 is formed in the upper part of the gap Y2 so as to form a substantially rectangular parallelepiped space at the end of the floor slab 12 and the paved road 13, and the floor slab 22 and the paved road 23 are formed. A notch 24 is formed at the end of the space so as to form a substantially rectangular parallelepiped space. Thereafter, as shown in FIG. 3, the bridge expansion / contraction device 30 as a unit is attached so as to be fitted into the notches 14 and 24. Thus, when replacing the existing bridge telescopic device, the bridge telescopic device 30 is a unit having a substantially rectangular parallelepiped shape and is therefore easy to install.

The effect of 1st Embodiment is demonstrated.
According to the bridge telescopic device 30 of the first embodiment, as shown in FIG. 2, the face plate 31 has a single thick plate shape, and both ends are supported by the plate support member 34 and the damper support member 35. Therefore, it can withstand a large impact force caused by the running of the vehicle. In addition, since the face plate 31 is disposed across the gap Y2, earth and sand and rain water are unlikely to flow down toward the lower part of the gap Y2, and the waterproof performance is difficult to deteriorate. In other words, in the bridge expansion / contraction device 30 of the present embodiment, unlike the conventional bridge expansion / contraction device 130 shown in FIG. 8, the seal material 133, the backup material 134, and the like are not provided below the face plates 131A and 131B. The water stop performance can be secured.

  The hydraulic damper 32 can absorb the displacement due to the temperature change of the bridge girders 10 and 20 while slightly expanding and contracting in the direction of the bridge axis, and the hydraulic damper 32 exhibits a damping force against the horizontal force in the event of an earthquake. However, it can be handled by expanding and contracting greatly. Therefore, in bridges in which the steel bearings are not replaced with the seismic isolation rubber bearings such as the bridges 1 and 1A of the present embodiment, the earthquake resistance can be improved by installing the bridge expansion and contraction device 30. And preventive maintenance measures against major earthquakes.

  Next, a second embodiment will be described with reference to FIG. FIG. 4 is a perspective view showing a bridge telescopic device 30A of the second embodiment. In the bridge telescopic device 30 of the first embodiment shown in FIG. 3, the hydraulic damper 32 is arranged coaxially with an axis extending in the bridge axis direction, but the bridge telescopic device of the second embodiment shown in FIG. 4. In 30A, the hydraulic damper 36 (cylinder tube 36a, cylinder rod 36b) is disposed at an angle of 10 degrees from the bridge axis direction to the bridge width direction so that it can expand and contract in the bridge axis direction and the bridge width direction. The angle at which the hydraulic damper 36 tilts can be changed as appropriate as long as it is smaller than 45 degrees.

  Further, the end surface 31d of the face plate 31A is a plane orthogonal to the axis from which the cylinder rod 36b extends. That is, unlike the end surface 31a of the face plate 31 of the first embodiment, the end surface 31d of the face plate 31A is not a plane orthogonal to the axis extending in the bridge axis direction, and the end surface of the face plate 31 of the first embodiment. It is inclined 10 degrees from the bridge width direction to the bridge axis direction with respect to 31a. Thus, the end surface 31d of the face plate 31A can be accurately pressed against the slightly tilted cylinder rod 36b. Since the other configuration of the second embodiment is the same as the configuration of the first embodiment described above, description thereof is omitted.

  According to the bridge telescopic device 30A of the second embodiment, among the displacements due to the temperature changes of the bridge girders 10 and 20, the hydraulic damper 36 is slightly not only for the displacement in the bridge axis direction but also for the displacement in the bridge width direction. Can be expanded and contracted. Therefore, when the bridge girder 10 and 20 have a relatively long length in the bridge width direction, the bridge girder 10 and 20 can smoothly absorb the displacement in the bridge width direction, and the bridge expansion and contraction device 30A is particularly preferable. . Other functions and effects of the second embodiment are the same as the functions and effects of the first embodiment described above, and a description thereof will be omitted.

As mentioned above, although each embodiment of the expansion-contraction apparatus for bridges concerning this invention was described, this invention is not limited to this, A various change is possible in the range which does not deviate from the meaning.
For example, in the bridge telescopic devices 30, 30 </ b> A, 30 </ b> B according to the first to third embodiments, the face plate 31 is attached to the notch 24 of the bridge girder 20, and the hydraulic damper 32 and the cover plate 33 are notched to the bridge girder 10. 14, the face plate 31 may be attached to the notch portion 14 of the bridge girder 10, and the hydraulic damper 32 and the cover plate 33 may be attached to the notch portion 24 of the bridge girder 20.

In the hydraulic damper 32, the cylinder tube 32 a is brought into contact with the end face of the notch 14 of the bridge girder 10 and the cylinder rod 32 b is brought into contact with the end face 31 a of the face plate 31, but the cylinder tube 32 a is brought into contact with the end face 31 a of the face plate 31. The cylinder rod 32b may be brought into contact with the end face of the notch portion 14 of the bridge beam 10.
Further, the type of the damper is not limited to the hydraulic damper, but may be a pneumatic damper and can be changed as appropriate.

  Further, the bridge expansion and contraction devices 30 and 30A may be installed on a bridge whose bridge girder is supported by a rubber bearing for seismic isolation. In this case, the horizontal force at the time of an earthquake can be attenuated by both the seismic isolation rubber bearing and the bridge expansion and contraction devices 30, 30A, 30B, and preventive maintenance measures for a large earthquake can be further improved.

DESCRIPTION OF SYMBOLS 1,1A Bridge 2 Abutment 3 Bridge pier 4,6 Movable bearing 5 Fixed bearing 10,20 Bridge girder 11,21 Main girder 12,22 Floor slab 13,23 Pavement 14,24 Notch 30,30A Bridge expansion / contraction device 31 Face Plate 31a End faces 32, 36 Hydraulic dampers 32a, 36a Cylinder tubes 32b, 36b Cylinder rod 33 Cover plate Y1, Y2 Spacing S1 Expansion gap

Claims (4)

A gap is formed between the abutment and the bridge girder or between the bridge girder,
In the bridge expansion and contraction device installed between the bridge structures facing each other at the upper part of the play,
A face plate attached to the opposing bridge structure and extending horizontally;
A cover plate attached to the opposite bridge structure and extending horizontally.
The face plate has a single thick plate shape and straddles the gap, and is arranged in a state where an expansion / contraction gap is formed between the end surface and the bridge structure on the other side,
The cover plate is disposed above the face plate across the expansion gap,
An expansion / contraction device for a bridge, comprising a damper that is interposed between an end surface of the face plate and the bridge structure on the other side and can expand and contract in a bridge axis direction. The bridge extension device according to claim 1,
The damper is a hydraulic damper having a cylinder tube that contacts one of the end surface of the face plate and the other bridge structure, and a cylinder rod that contacts the other end surface of the face plate and the other bridge structure. A telescopic device for bridges. In the expansion and contraction device for a bridge according to claim 1 or claim 2,
The expansion / contraction device for a bridge, wherein the damper is arranged to be slightly inclined from the bridge axis direction to the bridge width direction so that the damper can be expanded and contracted in the bridge axis direction and the bridge width direction. In the expansion-contraction apparatus for bridges as described in any one of Claims 1 thru | or 3,
The face plate, the cover plate, the damper, a plate support member that supports the face plate, and a damper support member that supports the damper are formed in a substantially rectangular parallelepiped integral unit. A telescopic device for bridges.

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