JPH08333718A - Bridge fall preventing device - Google Patents

Abstract

PURPOSE: To prevent a cable from being broken in the case where a bridge girder has fallen from a pier by such external force as an earthquake and suchlike by installing the cable in a gap between two anchoring means installed in respective ends to which adjacent bridge girders are opposed, and covering the cable with a protective cover. CONSTITUTION: A protective cover 23 consisting in a cylindrical elastic body made of polyethylene, carbon or steel is integrally formed up. Then a cable 10 installed in space between two anchor means 15 and 16 is covered with this protective cover 23 after being inserted thereinto. With this constitution, even if the cable 10 is strongly rubbed and hit by an angular part of a pier 1 by the falling of two bridge girders 2 and 3, this cable 10 will in no case be broken at all.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bridge fall prevention device for preventing a bridge girder from falling from a pier of a bridge when an external force such as an earthquake is applied to the bridge.

[0002]

2. Description of the Related Art Conventionally, bridges made of steel, reinforced concrete, or prestressed concrete adjacent to a pier are connected and mounted. For example, bridges for rivers and highways are mainly used as countermeasures against earthquakes. As shown in FIG. 6, a steel plate fall prevention device 4 is fixed between the side walls of the adjacent bridge girders 2 and 3 on the pier 1 with bolts and nuts.

[0003] The fall prevention device 4 prevents the bridge girder from falling off the pier due to shaking in the longitudinal direction of the bridge girder during an earthquake.

[0004]

However, depending on the magnitude of the seismic force, the fall prevention device 4 is broken,
The bridge girder could fall from the pier 1 and cause fatal damage to people, cars, objects, etc. on the ground. Therefore, recently, as shown in FIGS. 7 to 8, a bridge fall prevention device 5 in which a cable in which PC steel wires are bundled is installed between bridge girders 2 and 3 is attached.

As shown in FIG. 8, the structure of the bridge prevention device 5 is such that mounting brackets 6, 7 are rotatably mounted on the side wall surfaces of the bridge girders 2, 3 at appropriate intervals by bolts 6a, 7a. Have been.

A cable 10 is erected between brackets 8 and 9 erected at right angles to the side walls of the bridge girders of the mounting brackets 6 and 7, and cushioning materials 11 are interposed at both ends thereof.
It is fixed by the fixing nut 12.

As shown in FIG. 9, the end portion of the cable 10 is a sleeve (hereinafter referred to as a condominium) having a thread groove formed on the outer periphery, and a metal condominium 13 made of, for example, steel is fixed to the sleeve. The connection portion is covered with the cap 14.

[0008] With such a fall prevention device 5, for example, as shown in FIG.
3. If the bridge 3 is displaced and one of them falls, the bridge prevention device 5
The cable 10 holds the bridge girder 3 in the middle of falling, and protects the bridge girder 3 from reaching the ground.

In this way, the bridge girder is prevented from being damaged by the fall of the bridge girder. In the fall prevention device 5, as shown in FIG. 10, the bridge girder 3 falls from the pier 1 due to an external force such as a large earthquake. Occasionally, the cable 10 for preventing the bridge girder 3 from falling to the ground hits the corner 1a of the pier 1, and was sometimes damaged and broken by being rubbed at the corner.

That is, the surface of the cable 10 has a polyethylene coating layer for protecting the PC stranded wire, and the polyethylene coating layer is strongly rubbed or bent at the corner 1 a of the pier 1, and this portion is bent. Becomes weak and breaks here.

As described above, the conventional drop bridge apparatus has a problem to be solved in protecting the cable.

[0012]

The gist of the present invention for solving the above-mentioned problems is to provide a fixing means provided at each of opposite ends of an adjacent bridge girder, and a fixing means provided between the two fixing means. A fall prevention device consisting of an installed cable,
The cable in the fixing means is covered with a protective cover.

The protective cover is composed of two-part protective member; and the protective cover is colored in the same color as that of the bridge girder in order to blend the presence of the cable into the surroundings. Further, the protective cover is colored in a color that is not the same as the color of the bridge girder so that the presence of the cable becomes noticeable.

[0014]

According to the drop bridge device of the present invention, even if the cable is strongly rubbed against the corner of the pier due to the fall of the bridge girder, the cable is covered with the protective cover. Is prevented from being torn or broken at this portion.

Further, by dividing the protective cover into two parts, the protective cover can be attached even after the cable is installed on the fixing means and the bridge device is attached to the bridge girder. Further, by coloring the cable in a desired color, it is possible to meet the demand for the cable.

[0016]

Embodiments of the present invention will now be described in detail with reference to the drawings. For ease of understanding, portions corresponding to the conventional example will be described with the same reference numerals as in the conventional example.

As shown in FIG. 1, the bridge dropping device according to the first embodiment of the present invention is formed of metal (for example, metal) on the side walls of the bridge girders 2 and 3 placed adjacent to each other on the pier 1. ,Made of steel)
Are fixed to each other with the bolts 6a and 7a. However, when a large rotational force is applied around the axes of the bolts 6a, 7a, the fixing devices 15, 16 become rotatable.

A through hole through which the cable 10 is inserted is provided substantially at the center of the fixing members 15a, 16a of the flat plate members opposed to the fixing tools 15, 16.

Further, a cylindrical protective cylinder 22 made of metal or synthetic resin is fitted into the through-hole with both ends protruding. The protective cylinder 22 and the fastening member 15
The through holes a and 16a are loosely fitted.

A bundle of PC steel strands (for example, φ12.7 m
As shown in FIG. 2, there is a condominium 13 which is a metal sleeve fixed by caulking, as shown in FIG. A thread groove is engraved on the outer periphery of.

Next, a cylindrical protective cover 23 made of polyethylene, carbon or steel is integrally formed, and the protective cover 23 is inserted into the cable 10 to cover it. The length of the protective cover 23 is determined by the fixing tools 15, 1
6 so as to cover them with a slight gap.

After the cable 10 is covered with the protective cover 23, the half nut 20 as the movement preventing means 19 and the elastic material 21 are moved to the end of the cap 14 and screwed into the condominium 13 in advance. Fit or insert.

The material of the elastic member 21 is rubber elastic packing or a coil spring 21a (FIG. 4).
See) etc.

Then, the fixing devices 15 and 16 arranged to face each other.
The protective tube 22 of the fastening members 15a and 16a of the
The condominiums 13 at the end of 0 are inserted.

Further, as shown in FIG. 3, an elastic sponge 11c made of synthetic resin and a rubber made of rubber are used as the cushioning material 11 from the end of the outer periphery of the condominium 13 projecting from the fastening members 15a, 16a. The hard packing 11b and the metal pressure plate 11a are fitted in order. This cushioning material 11
As an elastic body of the elastic sponge 11c and the hard packing 11b, a coil spring 11d may be used as shown in FIG.

After that, the fixing nut 12 is screwed from the end of the outer peripheral portion of the apartment 13 to the screw portion, and the elastic sponge 11c is 3/4 to 2/2 of its unloaded thickness.
Then, the fixing nut 12 is tightened and fastened until the fixing nut 12 is pressed into a state where the fixing nut 12 is compressed to a degree of 3. As a result, the cable 10 is installed without being loosened by the elastic force of the elastic sponge 11c.

In this way, after the cable 10 is installed on the fixing members 15 and 16, the brackets 15 of the fixing members 15 and 16 which are arranged to face each other along the cable 10 are arranged.
Between the b, 15c, 16b, and 16c, split deflectors (deviator) 17, 17 are inserted so as to surround the outer periphery of the cable 10 and fixed by bolts 18 to be provided.

As described above, since the bridge cover device is provided with the protective cover 23 for protecting the cable 10 between the fixing tools 15 and 16, as shown in FIG. When it is dropped from 1, the cable 10 prevents the bridge girder 3 from dropping to the ground, and
The protective cover 23 abuts on the corner 1a of the pier 1.

Therefore, the surface of the cable 10 does not come into direct contact with the corner 1a of the pier 1 to be rubbed, scratches are prevented, and the cable 10 is prevented from breaking at this corner.

The second embodiment of the present invention differs from the first embodiment in that the protective cover 23 is divided into two parts.

By dividing the protective cover 23 into two parts,
After the cable 10 is laid between the fixing tools 15 and 16, for example, one of the protective covers is placed from above and below and fixed with bolts and nuts, so that the cable 10 after being laid is covered with the protective cover 23. I can do it.

Therefore, the work of attaching the protective cover 23 to the cable 10 is facilitated and the construction period is shortened.

The third embodiment of the present invention is to apply various colors to the protective cover 23. That is, for example, by coloring the surface of the protective cover 23 so as to have the same color as the color of the side surfaces of the bridge girders 2 and 3, it is not immediately recognized that the dropping device exists, and the dropping device is attached to the bridge girder. It is in a state of being melted, and it is possible to have unity.

On the contrary, if the surface of the protective cover 23 is colored with a color that is clearly different from the color of the side faces of the bridge girders 2 and 3, the presence of the bridge device can be immediately recognized visually.
The protection cover 23 can be emphasized.

[0035]

As described above, the bridge-falling device according to the present invention comprises a fixing means provided at each end of an adjacent bridge girder and a cable provided between the fixing means. In the device, since the cable in the fixing unit is covered with a protective cover, when the bridge girder falls from the pier due to an earthquake or the like, the protective cover prevents the cable from being scratched, etc. It has an excellent effect of preventing breakage at a portion.

Since the protective cover is a split protective member, the work of attaching the protective cover to the cable can be performed before and after erection of the cable, which facilitates construction. It has the effect.

Since the protective cover is colored in the same color or in the same color as the color of the bridge girder, there is an excellent effect that the drop bridge device can be made inconspicuous or noticeable.

[Brief description of drawings]

FIG. 1 is a front view of a bridge dropping device according to a first embodiment of the present invention.

FIG. 2 is a front view of the end of the cable of the first embodiment.

FIG. 3 is an enlarged side view of a fixing portion of the falling bridge prevention apparatus according to the first embodiment.

FIG. 4 is a front view (a) of the embodiment in which the shock-absorbing material and the elastic material are coil springs, which is the fall bridge prevention device according to the first embodiment, and the shock-absorbing material or the elastic material and the coil spring. It is a front view (b) when using together.

FIG. 5 is an explanatory diagram of a use state of the first embodiment.

FIG. 6 is a side view of a bridge prevention device according to a conventional example.

FIG. 7 is a perspective view of a bridge prevention device according to the conventional example.

FIG. 8 is a side view of a bridge fall prevention device according to the conventional example.

FIG. 9 is a longitudinal sectional view of an end of the cable.

FIG. 10 is an explanatory view of a working state at the time of an earthquake by the bridge prevention device according to the conventional example.

[Explanation of symbols]

 1 bridge pier, 2, 3 bridge girder, 10 cable, 11 cushioning material, 12 fixing nut, 13 sleeve (mansion), 14 cap, 15, 16 fixing tool, 15a, 16a fastening member, 17 deflecting tool, 19 movement prevention means, 21 elastic material, 22 protective cylinder, 23 protective cover.

Claims (4)

[Claims] 1. A fall-bridge prevention device comprising fixing means provided at opposite ends of adjacent bridge girders, and a cable installed between the fixing means, wherein a protective cover is provided on the cable of the fixing means. A fall prevention device characterized by being covered. 2. The fall prevention device according to claim 1, wherein the protection cover comprises a split protection member. 3. The bridge dropping device according to claim 1, wherein the protective cover is colored in the same color as the color of the bridge girder. 4. The fall prevention device according to claim 1, wherein the protective cover is colored in a color that is not the same as the color of the bridge girder.