JP7121544B2 - Fall prevention device and fall prevention structure for bearing members in bridge bearings - Google Patents

Description

TECHNICAL FIELD The present invention relates to a fall prevention device and a fall prevention structure for a support member in a bridge support.

Bearings are installed between the upper and lower structures of a bridge to support the load of the upper structure, allow rotation due to deflection, and follow expansion and contraction due to temperature changes.

In such bridge bearings, it has been confirmed that many of the members constituting the bearings, including the bolts, have come off as a result of damage to the bearings due to breakage of bolts and the like in recent earthquakes. If the dropped support member falls under the elevated structure, there is a risk of injuring a passerby or a passing vehicle. Moreover, even if the fallen bearing member remains in the lower structure, there is a risk of it falling due to aftershocks, which may hinder emergency inspections and emergency restoration work after an earthquake.

Conventionally, there has been proposed a device for preventing the bolts and washers from scattering and falling from the lower structure when the bolts that fix the side blocks, which are one of the supporting members, are broken (see Patent Document 1). Also, as a countermeasure against falling of the side block itself, there is known a method of attaching a chain to the side block and fixing the end of the chain to the lower structure (see, for example, paragraph 0006 of Document 1).

However, the above-described conventional countermeasures are all methods of preventing the falling of the support members individually, and cannot be applied to all support members. In addition, the above-mentioned conventional countermeasure for preventing the fall of only the side block uses a metal chain, which not only easily rusts, but also easily scratches the bearing when the metal chain contacts the bearing. Since chains are heavy, they are difficult to transport and install. In addition, a pair of side blocks are installed on both sides of the bearing in the direction of the bridge axis, and the chain is attached to each side block, and the ends of the chains are fixed to the substructure, so it takes time to install. There is also a problem.

JP 2007-64413 A

The present invention was made based on the above technical background, and achieves the following objects.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a fall prevention device and a fall prevention structure for a support member in a bridge support which can prevent all of the support members from falling, uses lightweight members, is easy to transport, and is easy to install. to do.

In order to achieve the above object, the present invention employs the following means.
That is, the present invention provides a bridge bearing portion in which a bearing is installed between an upper structure and a lower structure,
a resin flexible net arranged to surround the entire outer circumference of the bearing;
upper holding means for holding the upper end of the flexible net on the outer periphery of the upper end of the support;
lower holding means for holding the lower end of the flexible net on the outer periphery of the lower end of the support ;
The upper holding means and the lower holding means are upper flexible strips made of resin, which are formed and arranged in a loop shape by sewing the upper end portion and the lower end portion of the flexible net, respectively, in the circumferential direction. and a lower flexible strip,
retaining means for retaining the upper flexible strip and the lower flexible strip on the outer periphery of the upper end portion and the outer periphery of the lower end portion of the support, respectively;
A bridge bearing characterized in that said holding means for said upper flexible strip and said lower flexible strip comprises a plurality of fasteners provided on the outer periphery of the upper end and the outer periphery of the lower end of said support, respectively. In the fall prevention device for the support member in the part.

In the fall prevention device, the flexible strip may be made of a hollow braided rope .

In addition, the flexible net may employ a double-layered net structure comprising an inner net with a small mesh size and an outer net with a large mesh size .

In addition, the present invention provides a bridge support section in which a bearing is installed between an upper structure and a lower structure, and the bearing has a pair of side blocks installed on both sides in the bridge axis direction,
a resin flexible net arranged to surround the entire outer circumference of the bearing;
upper holding means for holding the upper end of the flexible net on the outer periphery of the upper end of the support;
lower holding means for holding the lower end of the flexible net on the outer periphery of the lower end of the support;
The upper holding means and the lower holding means are upper flexible strips made of resin, which are formed and arranged in a loop shape by sewing the upper end portion and the lower end portion of the flexible net, respectively, in the circumferential direction. and a lower flexible strip,
retaining means for retaining the upper flexible strip and the lower flexible strip on the outer periphery of the upper end portion and the outer periphery of the lower end portion of the support, respectively;
the means for retaining the upper flexible strip is to fit the upper flexible strip into a gap between the side block and the upper structure and wind it around the outer periphery of the upper end of the support;
In the fall prevention structure for a support member in a bridge support portion, the retention means for the lower flexible strip comprises a plurality of fasteners provided on the outer circumference of the lower end portion of the support. .

In the fall prevention structure as well , the flexible strip may be made of a hollow braided rope.

Further, the flexible net may be constructed of a double net consisting of an inner net with a small mesh and an outer net with a large mesh.

According to the fall prevention device and fall prevention structure for a bearing member of the present invention, all of the bearing members can be prevented from falling, the members used are lightweight and easy to transport, and the mounting work can be easily performed. can.

It is a perspective view of a bearing, showing an embodiment of the present invention. It is the front view which looked at the bridge axis direction of the bridge support part. It is a top view which shows some resin-made flexible nets. FIG. 4 is a plan view showing a braid rope used as a flexible resin strip. FIG. 4 is a plan view showing connecting portions at both ends of a flexible strip; It is the front view which showed another embodiment and looked at the bridge axis direction of the bridge support part.

Embodiments of the present invention will be described below with reference to the drawings. The illustrated embodiment is an example in which the present invention is applied to a bridge bearing portion in which multiple roller bearings are installed as bearings 10 between an upper structure (bridge girder) 14 and a lower structure (pier or abutment) 15. FIG. 1 is a perspective view of a multi-roller bearing, and FIG. 2 is a front view of the bearing as viewed in the direction of the bridge axis.

The multi-roller bearing 10 is known as one of the steel bearings, and its construction is briefly described below. The multi-roller bearing 10 comprises an upper shoe 11 , a lower shoe 12 and a bottom plate 13 . The upper shoe 11 is fixed to the upper structure 14 via the sole plate 16 , and the bottom plate 13 is fixed to the lower structure 15 by anchor bolts 17 . A shear key 18 for transmitting the horizontal load of the upper structure 14 to the bearing 10 is provided at the center of the upper surface of the upper shoe 11 .

Semi-cylindrical rotating parts 19, 19 are provided at the lower part of the upper shoe 11 and the upper part of the lower shoe 12, respectively. It is possible to rotate in the vertical direction. This allows rotation due to deflection of the upper structure 14 . Caps 21 are attached to both end portions of the pin 20 protruding from the rotating portions 19 , 19 .

A plurality of rollers 23 covered by a roller cover 22 are arranged between the lower shoe 12 and the bottom plate 13 so that the lower shoe 12 can move in the bridge axis direction with respect to the bottom plate 13 . As a result, expansion and contraction of the upper structure 14 due to temperature changes can be followed. A pair of side blocks 24, 24 are provided on both sides of the bottom plate 13 in the bridge axis direction. It can handle upward lift.

In the case of the multi-roller bearing 10 outlined above, in recent earthquakes, the central constricted portion of the pin 20 is broken, the cap 21 falls off, the side blocks 24 and their mounting bolts 25, the rollers 23, and the roller covers 22 . It is also confirmed that the support member has fallen off, such as the mounting bolt 26 thereof has fallen off. The present invention is a device that prevents these dropped bearing members from falling out of the undercarriage 15 .

The fall prevention device consists of a flexible net 30 (partial mesh is shown in FIG. 1) arranged so as to surround the entire outer circumference of the bearing 10, and the upper end of the flexible net 30 is attached and lower holding means 32 for holding the lower end of the flexible net 30 on the outer periphery of the lower end of the support 10 .

As shown in FIG. 3, the flexible net 30 is made by weaving resin fibers such as polyester into a net by raschel knitting. can do. This Nature Net has a high impact resistance due to its looped structure, and has a raschel structure, so even if a cut occurs at one point, the structure will not unravel any more. This net and the braided rope, which will be described later, have energy absorption performance, and it has been confirmed by an accelerated durability test that there was no clear decrease in yield strength even after exposure for 35 years.

The mesh shape of the flexible net 30 may be square mesh or diamond mesh, but any shape may be used. The mesh size is appropriately set according to the type of support, and can be selected from the range of 10 mm to 50 mm, for example. Smaller meshes are less energy absorbing than larger meshes, but can catch small bearing members such as bolts to prevent them from falling. A double net may be used, using a net with a small mesh size on the inside and a net with a large mesh size on the outside. By using such a double net, it is possible not only to catch both large and small bearing members, but also to increase the strength.

The flexible net 30 is wound around the outer periphery of the bearing 10 with a margin so as not to hinder the movement of the lower shoe 12 in the bridge axial direction, and both ends are wrapped with each other. Upper holding means 31 and lower holding means 32 for holding the upper and lower ends of the flexible net 30 on the upper and lower outer peripheries of the bearing 10, respectively, are made of resin. and a lower flexible strip 34 and a plurality of fasteners 35, 36 which are means for fastening these flexible strips 33, 34 to the upper and lower end perimeters of the bearing 10. As shown in FIG.

In this embodiment, as the upper and lower flexible strips 33, 34, hollow braid ropes made by weaving resin fibers such as polyester are used as shown in FIG. For this braided rope, one manufactured by Maeda Kosen Co., Ltd., for example, can be used, and has the characteristics described above. The upper and lower flexible strips 33 and 34 are attached to the upper and lower ends of the flexible net 30 in the circumferential direction through meshes. Further, the upper and lower flexible strips 33 and 34 are loop-shaped by connecting and fixing their ends.

The fasteners 35 and 36 are provided on the upper shoe 11 and the bottom plate 13, which are the upper and lower ends of the multi-roller bearing 10, respectively. The fasteners 35 and 36 are provided on the peripheral surfaces of the upper shoe 11 and the bottom plate 13, respectively, in this embodiment. Opening and closing type open eyebolts are used as the fasteners 35 and 36, and the upper and lower flexible strips 33 and 34 are attached by passing through these fasteners 35 and 36. As shown in FIG. Hook eye bolts, Marukan bolts, eye nuts, swivels, and the like can also be used as the fasteners 35 and 36 .

Both ends of the upper and lower flexible strips 33, 34 can be fixed as shown in FIG. The hollow braided cord ropes 33 and 34, which are flexible strips, have the property of increasing in diameter when contracted in the axial direction. Utilizing this property, one ends (appropriate length range) 33a, 34a of the braid ropes 33, 34 are shortened to increase the diameter. Then, the other end portions 33b and 34b are inserted into the one end portions 33a and 34a having the larger diameter, the meshes of the one end portions 33a and 34a are opened, and the other end portions 33b and 34b are pulled out. The other end portions 33b and 34b pulled out through the mesh are tied with, for example, a stop knot to form a bump portion 37 having a large diameter for preventing slippage. This braided rope can be easily cut to the required length with scissors on site and used.

Both ends of the braided cord ropes 33 and 34 fixed in this way become smaller in diameter when a tensile force acts on them, causing friction with the other ends 33b and 34b. Since the force is increased, the other ends 33b and 34b do not come off and the fixed state of both ends is maintained.

Assume that, in the above-described bearing portion, a load exceeding a predetermined level acts on the superstructure 14 due to earthquake motion, and the bearing 10 is damaged due to breakage of bolts or the like. However, according to the present invention, since the entire outer periphery of the bearing 10 is surrounded by the net 30, any bearing members that have fallen off as a result of damage, such as the pin 19 and its cap 21, the side block 24 and its mounting bolt 25, and the roller 23, can be removed. , the roller cover 22 and its mounting bolts 26 , etc. are caught by the flexible net 30 and are prevented from falling off the undercarriage 15 .

Also, according to the present invention, the flexible net 30 and the flexible strips 33, 34 used to cover the bearing 10 are both made of resin, unlike steel materials. , not only is it lightweight and easy to transport, but it does not rust, so it has excellent durability, and it does not adversely affect the coating of the bearing. Furthermore, since the net 30 is used to catch the fallen bearing member, it is excellent in visibility from a distance and easy to inspect during maintenance. Furthermore, when the need arises for repairing the bearing, it can be easily removed and attached.

When attaching the flexible net 30, upper and lower flexible strips 33 and 34 are attached through the mesh of the net 30 to form a loop, and fasteners 35 and 36 are attached to the upper and lower ends of the support 10 to Since the side flexible strips 33, 34 are simply supported by the fasteners 35, 36, the mounting work can be easily performed.

If a steel wire rope is used instead of a resin flexible strip such as the above-mentioned braided rope, the required length is measured on site for each size of the bearing, and cut to this length at the factory. After that, terminal processing must be done. There are wire clip processing, eye splice processing, sleeve compression processing, etc. for this terminal processing method, but wire clip processing changes the fastening force depending on the tightening force of the bolt, making it difficult to manage. On-site construction is generally difficult. Also, when connecting this as a single small rope, it will be connected with a U-shaped bolt or the like. Since a margin is required, it cannot be applied to small bearings.

FIG. 6 shows another embodiment, and is a front view of the support as seen in the bridge axis direction. This embodiment is an example in which the present invention is applied to a bridge bearing portion in which sealed rubber bearing plate bearings are installed as bearings 50 between an upper structure (bridge girder) 14 and a lower structure (pier or abutment) 15.

The sealed rubber bearing plate bearing 50 is known as one of the steel bearings and generally comprises an upper shoe 51 fixed to the upper structure 14 and a lower shoe 52 fixed to the lower structure 15 . The upper shoe 51 is provided with a shear key 56 for transmitting the horizontal load of the upper structure 14 to the bearing 50 .

A pot portion 53 is provided on the lower shoe 52, and a rubber plate and an intermediate plate (not shown) are accommodated in the pot portion 53, so that the upper shoe 51 can rotate in the vertical direction with respect to the lower shoe 52. . Further, the upper surface of the intermediate plate and the lower surface of the lower shoe 51 are in contact with each other through a sliding surface, and the upper shoe 51 is movable in the direction of the bridge axis. A pair of side blocks 54, 54 are provided on both sides of the pot portion 53 in the bridge axis direction. It can handle upward lift.

In the closed rubber bearing plate bearing 50, the upper end of the side block 54 reaches near the lower surface of the upper structure 14, and a gap 55 is formed between the upper surface of the side block 54 and the upper structure 14. In this embodiment, this gap 55 is used as a means for retaining the upper flexible strip 33 around the upper end of the bearing 50 .

That is, the upper flexible strip 33 attached to the flexible net 30 is fitted into the gap 55 , and the looped upper flexible strip 33 is wound around the outer circumference of the upper shoe 51 . Since the upper flexible strip 33 attached in this way covers the upper surface of the side block 54 with the upper part of the net 30, the upper flexible strip 33 does not drop off from the upper shoe 51. .

Fasteners 36 are provided on the peripheral surface of the lower shoe 52 in the same manner as in the above embodiment, and the lower flexible strip 34 is attached to these fasteners 36 . This embodiment also uses the same net 30 and upper and lower flexible strips as in the above embodiment.

The means for retaining the upper flexible strip 33 is not limited to the above two embodiments, and a fastener may be provided on the lower surface of the upper structure 14 . Similarly, the means for retaining the lower flexible strips 34 may be provided on the upper surface of the substructure 15 by means of fasteners. Alternatively, the means for retaining the lower flexible strip 34 may simply be wound around the outer circumference of the lower end of the support and tightened without using a fastener.

In the above two embodiments, examples were shown in which the present invention was applied to a bearing portion having a multiple roller bearing and a sealed rubber bearing plate bearing, respectively. can be applied.

Further, the present invention can be applied not only to the existing support of the support portion but also to the newly installed one.

10: Bearing (multiple roller bearing)
11: upper shoe 12: lower shoe 13: bottom plate 14: upper structure 15: lower structure 30: flexible net 31: upper holding means 32: lower holding means 33: upper flexible strip (braid rope)
34: Lower flexible strip (braid rope)
35, 36: Fastener 37: Tub (stop knot)
50: Bearing (closed rubber bearing plate bearing)
51: upper shoe 52: lower shoe 54: side block 55: gap

Claims (6)

In bridge bearings where bearings are installed between the superstructure and substructure,
a resin flexible net arranged to surround the entire outer circumference of the bearing;
upper holding means for holding the upper end of the flexible net on the outer periphery of the upper end of the support;
lower holding means for holding the lower end of the flexible net on the outer periphery of the lower end of the support ;
The upper holding means and the lower holding means are upper flexible strips made of resin, which are formed and arranged in a loop shape by sewing the upper end portion and the lower end portion of the flexible net, respectively, in the circumferential direction. and a lower flexible strip,
retaining means for retaining the upper flexible strip and the lower flexible strip on the outer periphery of the upper end portion and the outer periphery of the lower end portion of the support, respectively;
A bridge bearing characterized in that said holding means for said upper flexible strip and said lower flexible strip comprises a plurality of fasteners provided on the outer periphery of the upper end and the outer periphery of the lower end of said support, respectively. fall prevention device for the support member in the part. 2. A fall prevention device for a support member in a bridge support according to claim 1 , wherein said flexible strip comprises a hollow braided rope . 3. A fall prevention device for a support member in a bridge support according to claim 1 , wherein said flexible net comprises a double net consisting of an inner net with a small mesh size and an outer net with a large mesh size . A bridge bearing having a bearing installed between the superstructure and the substructure, the bearing having a pair of side blocks installed on both sides in the longitudinal direction of the bridge,
a resin flexible net arranged to surround the entire outer circumference of the bearing;
upper holding means for holding the upper end of the flexible net on the outer periphery of the upper end of the support;
lower holding means for holding the lower end of the flexible net on the outer periphery of the lower end of the support;
The upper holding means and the lower holding means are upper flexible strips made of resin, which are formed and arranged in a loop shape by sewing the meshes of the upper end portion and the lower end portion of the flexible net, respectively, in the circumferential direction. and a lower flexible strip,
retaining means for retaining the upper flexible strip and the lower flexible strip on the outer periphery of the upper end portion and the outer periphery of the lower end portion of the support, respectively;
the retaining means for the upper flexible strip is to fit the upper flexible strip into a gap between the side block and the upper structure and wind it around the outer periphery of the upper end of the support;
A fall prevention structure for a support member in a bridge support portion, wherein the holding means for the lower flexible strip comprises a plurality of fasteners provided on the outer periphery of the lower end portion of the support. 5. A fall prevention structure for a support member in a bridge support according to claim 4, wherein said flexible strip comprises a hollow braided rope. 6. A fall prevention structure for a bearing member in a bridge bearing according to claim 4 or 5, wherein said flexible net comprises a double net consisting of an inner net with a small mesh size and an outer net with a large mesh size.

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