JP2006022592A - Loop type bridge fall preventing device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily secure the amount of expansion gap while reducing cost through a decrease in the number of parts and facilitation of construction by simplifying the structure of an anchoring part regarding a loop type bridge fall preventing device. <P>SOLUTION: In this loop type bridge fall preventing device 1 for preventing the fall of a bridge girder by laying a connecting member between both anchoring parts, both anchoring parts 3, 4 are provided on the support part 2 side on one side, and the connecting member 5 is wound in approximately U-shape on the bridge girder 6 side on the other side. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a falling bridge prevention device that prevents a bridge girder from falling from a lower structure such as a pier or an abutment of the bridge when an external force such as seismic force acts on the bridge.

Seismic motion that is not assumed in the design is applied to the bridge, or the surrounding ground is destroyed or complex vibrations that are not predicted by structural members are applied, resulting in earthquake forces, displacements, and deformations that exceed expectations. There is a case. Conventionally, in order to prevent the bridge girder from falling from the lower structure such as the pier or the abutment for such an unforeseen situation, a falling bridge prevention device has been provided, and various types have been developed and provided in recent years. Yes. For example, as shown in FIG. 5, a connecting member 5 having a predetermined length is installed on an abutment 2 or a pier as a lower structure and a bridge girder 6 as an upper structure, and stoppers (fixing portions of fixing portions) are provided at both ends of the connecting member 5. A fixing buffer 7, a fixing nut 8, and a cap 9) are provided and fixed as the fixing portions 3 and 4 to prevent the bridge girder 6 from being dropped (see Patent Document 1).
JP 2001-64914 A

  And, as a function required for the conventional falling bridge prevention device, there is securing of the design clearance, because the structural damage as a whole is less when the entire bridge system allows a certain amount of displacement. In the road bridge specifications, it is recommended that 75% of the carry length is maximized as much as possible (hereinafter referred to as design clearance). In the PC cable type falling bridge prevention device as described above, the design clearance is normally secured by the spring 15 as shown in FIG.

However, after the Great Hanshin Earthquake, there is a problem that the structure becomes increasingly complex and expensive in order to satisfy the functions required for the fallen bridge prevention device. In particular, in order to secure 75% of the length required for the design clearance, it is necessary not only to have a large structure with multiple layers of springs, but also in the soil behind the lower structure, which is difficult to maintain. There is also a problem that a spring must be installed.
The present invention has been made in view of such a conventional problem, and can simplify the entire structural system of the falling-bridge prevention device, facilitate securing a large design clearance, and reduce costs. The object is to provide a fall-bridge prevention device.

  The gist of the loop type falling bridge prevention device according to the present invention is that, in the falling bridge prevention device for preventing a bridge girder from falling by connecting a connecting member between the two fixing portions, both the fixing portions are provided on one side of the support portion. The connecting member is wound in a substantially U shape around the bridge girder side.

A gap amount is secured between the bridge member and the fixing member on the support portion side, and a gap amount securing member is not required in both fixing portions;
Providing a semi-circular loop fixing portion on the bridge girder side where the connecting member of the portion wound in a substantially U-shape may come into contact;
A receiving beam for supporting a connecting member is provided in the loop fixing portion;
A lubricant for a connecting member is provided on the upper surface of the receiving beam;
A cushioning material made of an elastic member is provided at a location where the loop fixing portion comes into contact with the connecting member;
In the connection structure with the connecting member in both the fixing portions, one of the connecting members is fixed to the fixing portion;
Is included.

In the loop type bridge prevention device of the present invention, the bridge girder is supported by the loop-shaped connecting member. Therefore, there is no fixing portion on the bridge girder side to be prevented from being dropped, and the fixing device is halved to reduce the cost. Even if there is an unexpected situation in the bridge girder, the connecting member smoothly moves on the receiving beam, and the connecting member and the loop fixing portion come into contact with each other, so that the bridge girder is prevented from being dropped.
Furthermore, since the amount of play between the bridge girder is secured by the connecting member that is wound in a substantially U-shape on the bridge girder side, the design play amount in the road bridge specifications is easily constructed and required for the falling bridge prevention device. Function is ensured.
By securing the play amount on the bridge girder side, the fixing portion on the support side does not require a play amount securing member by an elastic member (spring or the like), the structure is simple, and the construction is also simplified. In addition, on one side of the fixing portion, one end portion of the connecting member has a fixed structure, so that the number of parts can be further reduced.
The receiving member of the loop fixing portion maintains the connecting member substantially horizontally without hanging down. By providing the lubricant on the receiving beam, the contact member can be moved more smoothly.
By providing a cushioning material made of an elastic member at a position where the loop fixing unit comes into contact with the connecting member, it is possible to alleviate the impact at the time of contact and to prevent the connecting member from being damaged.

  The loop type bridge failure prevention device according to the present invention will be described. In order to facilitate understanding of the invention, the same reference numerals as those in the conventional example are attached to the same components as in the conventional example. As shown in FIG. 1, the first embodiment of the loop-type falling bridge prevention device 1 is provided with fixing portions 3 and 4 on the support portion 2 side such as an abutment. A connecting member 5, which is a PC cable in which a strand made of steel wire is covered with a synthetic resin, is installed in a substantially half loop shape to prevent the bridge girder 6 from being dropped.

  Both the fixing portions 3 and 4 are provided on the support portion 2 side on one side. And the said connection member 5 is wound in the substantially U shape at the bridge girder 6 side of the other side. In this embodiment, the diameter of the substantially U-shaped portion of the connecting member 5 is about 2000 mm.

  In the fixing portions 3 and 4, a steel stopper (hereinafter referred to as a condominium) 5 a with a thread groove provided at an end portion of the connecting member 5 is composed of a steel bearing plate and a rubber shock absorber. The fixing buffer 7 is inserted, and a fixing nut 8 is fixedly attached to the screw groove. A cap 9 is put on the fixing portions 3 and 4 for rust prevention.

  As shown in FIG. 1, the connecting member 5 has a substantially U-shaped portion on the side of the bridge beam 6 and is wound around the bridge beam 6 with a clearance a. Therefore, in the fixing portions 3 and 4 on the support portion 2 side, the conventional spring 15 as a clearance amount securing member is not necessary, and the structure is simple.

  On the bridge girder 6 side, a semicircular loop fixing portion 6a in which the connection member of the portion wound in the substantially U shape comes into contact is provided. The loop fixing portion 6a is made of, for example, concrete and may be provided integrally with the bridge girder 6 or may be added later for adding a falling bridge prevention device. Further, a cushioning material 10 made of an elastic member such as rubber is fixed to a portion of the surface of the loop fixing portion 6a that comes into contact with the connecting member 5 by a plurality of anchors 10a whose diameter is increased. Thereby, at the time of contact between the connecting member 5 and the loop fixing portion 6a, the impact is reduced and scratches are prevented.

  As shown in FIGS. 2 to 3, the loop fixing portion 6 a is provided with a steel receiving beam 11 that supports the connecting member 5 so as not to hang down. The receiving beam 11 is integrally formed by embedding a part thereof in the loop fixing portion 6a and projecting the other horizontally. In addition, it protrudes outside more than the position of the half loop-shaped part of the connection member 5 in normal arrangement | positioning.

  On the upper surface of the receiving beam 11, a sliding member 12 for a connecting member is fixed by, for example, a bolt 13. The sliding material 12 is made of, for example, nylon resin or other hard synthetic resin. The movement of the connecting member 5 becomes smoother. In addition, in order to protect the outer surface of the connecting member 5 from scratches, a trumpet-shaped steel sheath 14 that expands toward the outside is provided.

  As shown in FIG. 4, such a loop type falling bridge prevention device 1 has a connecting member 5 installed in a half-loop shape on a bridge girder 6 to secure a free space “a” and fix an apartment 5 a to fixing units 3 and 4. The nut 8 is screwed and fixed. As a result, the number of parts can be reduced with a simple structure, the design clearance amount a can be secured, and the function can be fully exhibited.

  As a second embodiment of the present invention, in the connection structure between the fixing portions 3 and 4 and the connecting member 5, one of the connecting members 5 is fixed to the fixing portion. By doing so, it is possible to reduce the number of parts by eliminating the fixing member in the fixing unit on one side, thereby reducing the cost.

It is a top view of the loop type fallen bridge prevention apparatus 1 which concerns on 1st Example of this invention. It is a front view which expands and shows the loop fixing | fixed part 6a and the receiving beam 11 in the loop type fallen bridge prevention apparatus 1 of the same invention. It is an enlarged side view of the receiving beam 11 and the lubricant 12. It is explanatory drawing which shows the use condition of 1st Example of the same invention. It is explanatory drawing which shows the usage example of the fallen bridge prevention apparatus which concerns on a prior art example.

Explanation of symbols

1 Loop-type falling bridge prevention device,
2 support part,
3 fixing section,
4 Fixing part,
5 connecting members,
6 Bridge girder, 6a Loop fixing part,
7 Fixing cushion,
8 fixing nut,
9 cap,
10 cushioning material,
11 Receiving beam,
12 Lubricant,
13 volts,
14 sheath,
15 Spring.

Claims (7)

In the fall prevention device that prevents the bridge girder from falling by installing a connecting member between the fixing parts,
The fixing parts are provided on one side of the support part, and the connecting member is wound in a substantially U shape on the bridge girder side of the other side;
Loop-type falling bridge prevention device characterized by The amount of play between the bridge girder is secured by the connecting member of the portion wound in a substantially U shape on the bridge girder side, and there is no need for a play amount securing member in both fixing parts on the support part side,
The loop-type falling bridge prevention device according to claim 1. Provided on the bridge beam side a semi-circular loop fixing portion in which the connecting member of the portion wound in a substantially U shape may come into contact,
The loop-type falling bridge prevention device according to claim 1. The loop fixing portion is provided with a receiving beam for supporting the connecting member,
The loop-type falling bridge prevention device according to any one of claims 1 to 3. The upper surface of the receiving beam is provided with a lubricant for the connecting member,
The loop type falling bridge prevention device according to claim 4. Provided a cushioning material by an elastic member at a location where the loop fixing unit contacts the connecting member,
The loop type falling bridge prevention device according to any one of claims 3 to 5. In the connection structure with the connecting member in both fixing portions, one of the connecting members is fixed to the fixing portion,
The loop-type falling bridge prevention device according to any one of claims 1 to 6.

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