JP3768144B2 - Fall bridge prevention device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a falling bridge prevention device for preventing a bridge girder from falling from a lower structure such as a pier or an abutment at the time of a disaster such as an earthquake.
[0002]
[Prior art]
If a horizontal force acts on the pier or abutment due to an earthquake or the like, not only will the pier or abutment be damaged, but they will also vibrate, causing damage such as dropping or dropping the bridge girder. In order to prevent such a bridge girder from falling, there are known ones in which the girder on the pier and between the abutment and the girder are connected by a PC cable or by a link. However, especially in the case of a huge earthquake, these devices cause a phenomenon that a large impact force is applied to the connecting portion between the PC cable or the link and the girder, and the connecting portion is broken.
[0003]
For this reason, in recent years, various types of fallen bridge prevention devices using PC cables have been developed in which a buffer mechanism combining a spring and rubber is attached to a bracket for connecting a PC cable and a bridge girder. However, those having such a buffer mechanism have a problem that the structure is complicated, the overall shape is large, and the cost is high.
[0004]
[Problems to be solved by the invention]
The present invention has been made based on the technical background as described above, and achieves the following object.
An object of the present invention is to provide a fallen bridge prevention device that can be simplified in structure, compact in overall shape, and reduced in manufacturing cost.
[0005]
[Means for Solving the Problems]
The present invention employs the following means in order to achieve the above object.
That is, this invention is a connecting member in which one end is attached to the bridge axial direction end of the bridge girder and the other end is attached to the bridge axial direction end or abutment of the bridge girder facing the bridge girder. The bridge girder prevention device for preventing the bridge girder from falling from the lower structure of the pier, abutment, etc.
A bracket provided at an end of the bridge beam or the abutment and having an insertion hole through which the connecting member is inserted;
One surface is fixed to the bracket so as to compressively deform in the bridge axis direction, and a shock-absorbing rubber body having an insertion hole through which the connecting member is inserted,
A bearing plate fixed to the other surface of the buffer rubber body and having an insertion hole through which the connecting member is inserted;
A stopper fixed to an end of the connecting member that is inserted into each insertion hole of the buffer rubber body and the bearing plate and protrudes from the bearing plate;
A coil spring that is disposed on the outer periphery of a connecting member protruding from the bracket, and is inserted into each insertion hole of the buffer rubber body and the pressure bearing plate, with one end locked to the bracket and the other end locked to the stopper. When,
And a cylindrical cover fixed to the bearing plate so as to cover the connecting member protruding from the bearing plate.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 show an embodiment of the present invention. FIG. 1 is an overall front view taken along the direction perpendicular to the bridge axis, and FIG. 2 is a horizontal sectional view. This embodiment is an example in which the present invention is applied to a simple girder between two or more spans. In this simple girder bridge, the ends of the bridge girder 3 and 3 in the bridge axis direction are installed facing each other at an interval above the pier 2 which is a lower structure.
[0007]
The falling bridge prevention devices 1 and 1 are attached to the end portions of the bridge girders 3 and 3 and have a connecting cable 4 which is a member for connecting the end portions of the girders. As shown in FIG. 2, the falling bridge prevention device 1 has a bracket 5, and this bracket 5 is fixed to a web of a bridge girder 3 (in the case of a steel girder) by a plurality of mounting bolts 7 via a liner plate 6. 8, a pair of upper and lower horizontal plates 9, 9 provided on the mounting plate 8, a vertical plate 10 perpendicular to the bridge axis direction across the intermediate portion of these horizontal plates 9, 9, and the horizontal plates 9, 9 It consists of a pair of partition plates 11 and 11 provided.
[0008]
One surface of the buffer rubber body 12 is fixed to the vertical plate 10, and a pressure bearing plate 13 is fixed to the other surface of the buffer rubber body 12. That is, the buffer rubber body 12 is fixed to the vertical plate 10 by the plurality of bolts 14 so as to be sandwiched between the vertical plate 10 and the pressure bearing plate 13. The buffer rubber body 12 and the pressure bearing plate 13 are rectangular and are attached to the vertical plate 10 while being exposed to the atmosphere. For this reason, a rubber having good weather resistance, such as chloroprene rubber, is used as the buffer rubber body 12. Further, the exposed surface of the bearing plate 13 is subjected to a hot dip galvanizing process. The tightening degree of the bolt 14 is such that rainwater or the like does not enter between the vertical plate 10 and the buffer rubber body 12 and between the buffer rubber body 12 and the bearing plate 13. Do not add.
[0009]
A deflection block 16 is fixed to an entrance of a space 15 defined by the horizontal plate 9 and the partition plates 11 and 11. The deflection block 16 is composed of two divided blocks formed of a synthetic resin such as polyethylene, and has an insertion hole 17 for the connecting cable 4 that gradually expands on the inlet side.
[0010]
The vertical plate 10, the shock absorbing rubber body 12, and the bearing plate 13 have insertion holes 18, 19, 20 for the connection cable 4. The connection cable 4 is inserted through the insertion holes of the deflection block 16, the vertical plate 10, the shock absorbing rubber body 12, and the pressure bearing plate 13, and the end 21 protrudes from the pressure bearing plate 13. The connecting cable 4 includes a PC steel strand 22a, a steel apartment 22b into which the PC steel strand 22a is inserted and fixed, and a synthetic resin covering material 22c that covers the PC steel strand 22a. Yes.
[0011]
A male screw portion 23 is formed at the end portion 21 of the connecting cable 4, that is, the end portion 21 of the apartment 22b. The male screw portion 23 is provided with a washer 24 and a nut 25 constituting a stopper. A cylindrical coil spring 26 having a slightly larger diameter is disposed on the outer periphery of the connecting cable 4 protruding from the vertical plate 10. A part of the coil spring 26 is inserted into the insertion holes 19 and 20 of the buffer rubber body 12 and the bearing plate 13, one end is locked to the vertical plate 10, and the other end is locked to the washer 24. By appropriately changing the mounting position of the nut 25, the spring force of the coil spring 26 can be changed.
[0012]
The connecting cable 4 protruding from the bearing plate 13 is covered with a cover 27. The cover 27 has a cylindrical shape with the front end opened and the rear end closed, and the open end of the cover 27 is fixed to the bearing plate 13 with a bolt 28 in a watertight manner. The cover 27 is made of steel or polyethylene. When the cover 27 is made of steel, the surface is subjected to hot dip galvanization.
[0013]
When the bridge girder 3 receives an inertial force due to a large earthquake in the above-described fallen bridge prevention device, a horizontal impact force P acts on the connecting cable 4. Due to this impact force, the coil spring 26 is compressed and deformed, and is pushed into the insertion holes 19 and 20 of the buffer rubber body 12 and the bearing plate 13. As a result, the washer 24 abuts against the bearing plate 13 and the cushioning rubber body 12 is compressed and deformed in the bridge axis direction. The impact is alleviated by the compression deformation of the buffer rubber body 12.
[0014]
A support pipe 30 may be provided at the periphery of the insertion hole 20 of the support plate 13. By providing such a support pipe 30, the coil spring 26 is surely pushed into the insertion holes 19 and 20 and the support pipe 30 at the time of compression deformation. Therefore, a horizontal force can be reliably applied to the buffer rubber body 12 without increasing the thickness of the bearing plate 13.
[0015]
According to the above embodiment, the coil spring 26 is inserted and disposed in the respective insertion holes 19 and 20 of the buffer rubber body 12 and the bearing plate 13, so that the overall length is shortened. Since the buffer rubber body 12 and the support plate 13 are exposed, and the cover 27 covers only the connection cable 4 protruding from the support plate 13, the cover can be small. Since the coil spring has a cylindrical shape, the cost is lower than that of a conical shape, and the spring strength can be easily calculated. As described above, the structure is simplified, the overall shape is made compact, and the manufacturing cost is reduced.
[0016]
The above embodiment is merely an example, and the present invention can take various forms. For example, in the above-described embodiment, the structure for connecting the beams on the bridge piers is shown. However, the present invention can also be applied when connecting the abutment and the bridge beams.
[0017]
【The invention's effect】
As described above, according to the present invention, the structure is simplified, the overall shape is made compact, and the manufacturing cost can be reduced.
[Brief description of the drawings]
FIG. 1 is a front view showing an embodiment of the present invention, as viewed in a direction along a direction perpendicular to a bridge axis.
FIG. 2 is a horizontal sectional view of the same embodiment.
[Explanation of symbols]
1: Falling bridge prevention device 2: Bridge pier 3: Bridge girder 4: Connection cable 5: Bracket 10: Vertical plate 12: Buffer rubber body 13: Bearing plate 14: Bolt 17: Insertion hole 18: Insertion hole 19: Insertion hole 20: Insertion hole 21: End 24: Washer 25: Nut 26: Coil spring 27: Cover

Claims (1)

One end is attached to the bridge axial direction end of the bridge girder, and the bridge girder is a pier by a connecting member to which the other end is attached to the bridge axial direction end or abutment of the bridge girder facing the bridge girder , A fallen bridge prevention device for preventing falling from a lower structure such as an abutment,
A bracket provided at an end of the bridge beam or the abutment and having an insertion hole through which the connecting member is inserted;
One surface is fixed to the bracket so as to compressively deform in the bridge axis direction, and a shock-absorbing rubber body having an insertion hole through which the connecting member is inserted,
A bearing plate fixed to the other surface of the buffer rubber body and having an insertion hole through which the connecting member is inserted;
A stopper fixed to an end of the connecting member that is inserted through each insertion hole of the buffer rubber body and the bearing plate and protrudes from the bearing plate;
A coil spring which is disposed on the outer periphery of a connecting member protruding from the bracket, and is inserted into each insertion hole of the buffer rubber body and the pressure bearing plate so that one end is locked to the bracket and the other end is locked to the stopper. When,
A falling bridge prevention device comprising: a cylindrical cover fixed to the bearing plate so as to cover the connecting member protruding from the bearing plate.

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