JPH05292641A - Laying method of power cable at end part of bridge - Google Patents

Abstract

PURPOSE:To provide a laying method of a power cable at an end part of bridge through which a power cable can be deformed stably in a limited space. CONSTITUTION:In the method for laying a power cable 2, secured at an end part of a bridge, in curved shape between the end part of bridge and a ground side fixed point 6, the power cable 2 is gripped at two points in the intermediate curved part by means of cleats 3 linked with a three hinge arch constituted of main pins 5a-5c and two linking arms 4 thus supporting the curved power cable 2.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for laying a power cable installed on a bridge at the bridge end.

[0002]

2. Description of the Related Art Recently, power cables are often installed on bridges, but at the end of the bridge, as shown in FIG.
Axial expansion and contraction M due to thermal expansion and contraction of the bridge girder 1, vertical angle θ of the bridge girder 1 and angle change in the horizontal direction (not shown), called angular breakage, occur, but these occur between the bridge girder 1 and the pier 11. The support sliding device 12 interposed between them corresponds. For this reason, it is necessary to lay the power cable and the cable sill frame laid on the bridge so that the bridge girder can be stretched and bent at the bridge end.

FIG. 5 is an explanatory view of an example of a conventional method of laying a power cable at the bridge end. As shown in the drawing, the cable offset portion C for absorbing expansion and contraction formed on the bridge girder 1 and the corner bending absorbing portion D formed between the bridge girder 1 and the above-ground side fixed point 18 correspond to each other. Offset section C
Is a portion that absorbs expansion and contraction due to a change in the slack shape of the power cable 2. Normally, only the power cable 2 may be installed, but when the expansion or contraction amount is about 1 m or more, a link mechanism 13 called a panda graph is installed side by side, The deformation of the electric power cable 1 is restricted by the deformation of.

The corner bending absorbing portion D extends from the frame of the link mechanism 13 of the offset portion C, and has one end fixed to the fixing point 18 on the ground portion at the middle portion of the attachment frame 14 through the pins 16a and 16b. 15 is installed, and the corners of the frame can be freely bent by the pins 16a and 16b. At this time, a slight length change is added to the power cable 2 due to a change in the angle of the frame due to the bending of the corner, so that a slight slack 2a is provided as shown in the figure. In the figure, 17 is a fixed point of the link mechanism 13 and the power cable 2, and 19 is a sliding portion between the bridge girder 1 and the cable frame 14.

[0005]

As described above, in the conventional method of laying the power cable at the bridge end, since the offset portion for expansion and contraction absorption and the corner bending absorption portion are formed separately, a large area is formed on the bridge. There was a problem that it required space.

[0006]

SUMMARY OF THE INVENTION The present invention solves the above problems and provides a method of laying a power cable at the end of a bridge to obtain a stable deformation in a small space. Fix it at the bridge end and lay a power cable in a bent shape between it and the fixed point on the ground side, hold the middle part of the bent shape of the power cable at two cleats, and attach the cleat to the three main pins. This is to support and deform a bent power cable by connecting it to a three-hinge arch composed of two arms that connect it.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of a method for laying a power cable at a bridge end portion of the present invention. As shown in the drawing, the electric power cable 2 laid on the bridge is fixed at the bridge girder end A with the cleat 3 and laid in a curved shape B between the fixed point 6 on the ground side. Then, the cleat 3 holds two intermediate portions of the power cable 2 laid in the bent shape B at two positions. Attach the cleat 3 of the fixed part to the three main pins 5a, 5b, 5c.
And a three-hinge arch composed of two arms 4 connecting them with each other.

[0008]

FIG. 2 is an explanatory view of the situation of occurrence of displacement at the fixed point A at the end of the bridge girder in FIG. As shown in the figure, displacement occurs in the bridge axis direction X, the bridge axis perpendicular direction Y, and the vertical direction Z.
The displacement in the X direction is the maximum that occurs due to changes in the temperature of the bridge, and is about 1000 mm, for example. See you Y
The direction is caused by the change in the horizontal angle of the bridge, and the displacement in the Z direction is caused by the change in the vertical angle.
It is smaller than the direction, for example, about several mm to several tens of mm.
Therefore, the bend-shaped power cable has these X, Y,
It is necessary to absorb the displacement in the Z direction.

FIG. 3 is an explanatory view of a concept of a connection point between a three-pin hinge arch composed of three main pins and two arms connecting the main pins and a bent power cable. When the bridge girder end point A when the displacement in the X direction = 0 absorbs the displacement M in the X direction,
Move to point A ', and the power cable and arch will be in the position shown by the broken line in the figure. What is important here is that the points where the power cable and the arch intersect after deformation are points B'and C '. That is, if the cable and the arch are integrated at the points B and C before the deformation, even after moving by M,
Since B'and C'are integrated, the arm can control the power cable without difficulty. This makes it possible to absorb the displacement in the X direction.

Further, the change in the Z direction, for example, upwards means that
Since it is equivalent to moving the fixed point D on the ground portion side in the figure downward by N, it can be absorbed similarly to the displacement at the point A. Furthermore, for the Y-direction displacement perpendicular to the paper surface, the normal number
Since it is as small as mm, it can be absorbed by the elastic deformation of the arch and cable. For example, if R = 5000mm, arc length = 78
Since it is 50 mm, it is possible to fix one end of 7850 mm and bend the other end by several mm by elastic deformation. Alternatively,
It is also possible to provide play so that the main pins at points A, E, and D can slightly move in the vertical direction on the paper surface, and this play can be absorbed by displacement in the Y direction.

The positions of the cross points B'and C'of the power cable after the deformation and the arches can be easily obtained geometrically or by drawing because the arc length is invariable. Further, although the arm of the restricting arch has the same arcuate shape (AE) as the power cable in FIG. 3, it may be a straight line connecting between A and E for facilitating the manufacture. However, in that case, since a distance is generated between the arm and the points B and C, it is necessary to install the pedestal 7 for filling the distance.

[0012]

As described above, according to the method for laying the power cable at the bridge end of the present invention, the offset portion and the corner bending absorbing portion are not separately provided unlike the conventional case, so The mounting space becomes smaller,
The weight of the socks is also reduced. Further, since the bend forming portion of the power cable is connected to and supported by the three-hinge arch, the power cable repeats stable deformation, and there is no fear of deformation due to its own weight.

[Brief description of drawings]

FIG. 1 is an explanatory view of a specific example of a method of laying a power cable at a bridge end portion of the present invention.

FIG. 2 is an explanatory diagram of a displacement occurrence state at a fixed point A at an end of the bridge girder in FIG.

FIG. 3 is an explanatory diagram of a concept of a connection point between a hinge arch and a curved power cable.

FIG. 4 is an explanatory view of expansion / contraction and angle change of a bridge girder at a bridge end.

FIG. 5 is an explanatory diagram of an example of a conventional method of laying a power cable at a bridge end.

[Explanation of symbols]

 1 bridge girder 2 power cable 3 cleat 4 arm 5a, 5b, 5c main pin 6 ground side fixed point 7 pedestal A fixed point at bridge girder end B bend forming part of power cable

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Takashi Matsui, 1-3 1-3 Shimaya, Konohana-ku, Osaka City, Sumitomo Electric Industries, Ltd. (72) Inventor, Naohide Urakawa 3-chome, Nakanoshima, Kita-ku, Osaka No. 22 In Kansai Electric Power Co., Inc. (72) Inventor, Tadashi Kawamata, 1-20-19 Shimanouchi, Chuo-ku, Osaka City, Newgeec Co., Ltd. (72) Innovator: Sadao Mizutani, 5-1-1, Hidaka-cho, Hitachi No. Hitachi Power Systems Co., Ltd. Power System Laboratory

Claims (1)

[Claims] 1. A curved linear shape of an electric power cable for expansion / contraction in the axial direction of the bridge at the end of the bridge where the electric power cable is laid and installed, vertical expansion / contraction caused by corner bending of the bridge, and horizontal expansion / contraction perpendicular to the bridge axis. In the method of laying a power cable to be absorbed by, the power cable is fixed at the bridge end, and the power cable is laid in a curved shape between the fixed point on the ground side and the middle portion of the curved shape of the power cable is cleats 2. In a bridge end, which is characterized in that the cleat is gripped at several points and is connected to a three-hinge arch consisting of three main pins and two arms connecting the cleat to support and deform a curved power cable. How to lay power cables.