JPH0765293B2 - PC cable stayed bridge cable construction method - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] When constructing a PC cable-stayed bridge, the present invention develops a diagonal cable of PC steel wire or the like wound in a coil shape while developing a main tower and a bridge girder. It relates to the method of laying the diagonal cable of the PC cable-stayed bridge to be laid between.

[Conventional technology]

When constructing a PC cable-stayed bridge, PC steel wire is used for the diagonal cable that is erected between the main tower and the bridge girder, and this diagonal cable has a large diameter so that it can be easily handled for transportation. It is wound in a coil and transported.

In addition, by simply unfolding the coiled diagonal cable and pulling it out in a straight line, the twisting when wound into a coil remains, and work such as pulling in, inserting, and arranging in a narrow yard can be performed. Since it is difficult and dangerous, it is necessary to remove the twist of the diagonal cable when installing it between the main tower and the bridge girder.

Conventionally, the following two methods are generally performed as methods for removing the twist of the diagonal cable.

One of them is a method of anchoring one end of the diagonal cable on the main girder below the main tower after the main tower is pulled in, and mounting the other end of the uncoiler on the truck to deploy it.

The other is a method in which the uncoiler is set at a position where the entire diagonal cable can be pulled out, one end of the diagonal cable is drawn out horizontally by using a winch or the like, and then pulled up to the main tower by a tower crane.

[Problems to be solved by the invention]

However, in any of the methods 1 and 2 above, since the unloader and diagonal cable are installed outside the working range of the tower crane, it is necessary to install a mobile crane or truck on the bridge girder. It was necessary to secure a large space for the mobile crane and truck to move sufficiently.

Moreover, the uncoiler on which the diagonal cable is wound often protrudes from the bed of the truck, and there is a safety problem in traveling with the uncoiler.

The present invention has been made to solve the above problems, efficiently remove the twist of the diagonal cable in a very limited space while efficiently using the diagonal cable between the main tower and the bridge girder, and It is an object of the present invention to provide a method for laying a diagonal cable of a PC cable-stayed bridge that enables safe laying.

[Means for solving problems]

The method for constructing the diagonal cable of the PC cable-stayed bridge according to the present invention is
A tower crane that spans a diagonal cable wound in a coil shape according to the method of deploying this diagonal cable, and bridges the diagonal cable pulled out from this unleela between the main tower and the bridge girder. And rotating the uncoiler in the developing direction of the diagonal cable, pulling out one end of the diagonal cable by the tower crane, and gradually pulling up while rotating to remove the twist of the diagonal cable. Next, one end of the diagonal cable is drawn into a fixing steel pipe attached to the main tower and fixed, and then a portion of the diagonal cable near the uncoiler is hung by the tower crane and rotated. While gradually pulling up, the twist of the diagonal cable was removed, and the entire length of the diagonal cable was pulled out from the unloader. , Stretching the other end of the diagonal member cable fixing portion direction of the bridge girder with varying suspended by the tower crane, and to fix the fixing portion of the bridge girder.

〔Example〕

Hereinafter, a method for constructing a diagonal cable of a PC cable-stayed bridge according to the present invention will be described based on one embodiment illustrated in the drawings.

In the figure, reference numeral 1 is a main tower of a PC cable-stayed bridge, 2 is a bridge girder installed on the main tower, and 3 is a diagonal cable installed between the main tower 1 and the bridge girder 2.

Further, reference numeral 4 is a diagonal cable 3 between the main tower 1 and the bridge girder 2.
Is a tower crane for erection of the tower crane, 5 is a retractor for retracting one end 1a of the diagonal cable 3 erected between the main tower 1 and the bridge girder 2 into the main tower 1, and reference numeral 6 is a coil having a predetermined diameter. It is an uncoiler that linearly unfolds (rewinds) the diagonal cable 3 that is wound into a shape and carried into the site.

The uncoiler 6 is a device that horizontally mounts the diagonal cable 3 wound in a coil shape and rotates the diagonal cable 3 in the developing direction.

A circular plate-shaped rotary base 7 is attached to the unclealer 6, and a pin rack 8 continuous in the circumferential direction is attached to the outer periphery of the rotary base 7.

In addition, a drive motor 9 is attached near the rotary base 7,
The rotation shaft of this drive motor 9 meshes with the pin rack 8,
A sprocket 10 for rotating the rotary base 7 is attached.

An outer frame 11 formed in a circular shape and holding the coil-shaped diagonal cable 3 placed on the rotary pedestal 7 is attached to the outside of the rotary pedestal 7 separately from the rotary pedestal 7. There is.
Further, an inner frame 12 which is formed in a circular shape at the center of the rotary pedestal 7 and which rotates together with the rotary pedestal 7 to hold the coiled diagonal cable 3 is attached.

In such a configuration, in order to install the diagonal cable 3 between the main tower 1 and the bridge girder 1, first, the coiled diagonal cable 3 is placed on the rotating base 7 of the uncoiler 6, and the bundle thereof is bundled. Solve

Next, the drive motor 9 is driven to rotate the uncoiler 6 in the developing direction of the diagonal cable 3 to add one end 3a of the coiled diagonal cable 3 to the length of the fixing steel pipe 1a by about 2 m. It is pulled out and hooked on the hook 14 of the tower crane 4 via the hanging jig 13.

Next, the uncoiler 6 is again attached to the coiled diagonal cable 3
While gradually rotating in the unfolding direction, the hook 14 of the tower crane 4 is gradually pulled up to gradually pull up one end 3a of the coiled diagonal cable 3.

As a result, the diagonal cable 3 wound in the coil shape is drawn out in a straight line, and at the same time, the twist of the drawn out part is removed.

In this case, when the hook 14 of the tower crane 1 is rotatably attached, the twist of the diagonal cable 3 is naturally removed even when the diagonal cable 3 rotates together with the hook 14.

Also, the speed at which the diagonal cable 3 is pulled out from the uncoiler 6 and one end of the diagonal cable 3 by the crane 4
There is a difference in the speed at which 3a is pulled up, and even if one of them is too fast or too slow, it is possible to prevent the twisted cable 3 from remaining twisted or newly twisted.

Next, one end 3a of the coiled diagonal cable 3 is connected to the pulling wire 15, and the pulling wire 15 is pulled by the pulling device 5 to pull the one end 3a of the diagonal cable 3 into the fixing steel pipe 1a. Established in 1a.

Next, the hanging jig 13 of the crane 4 is temporarily removed from the diagonal cable 3, and the hanging jig 13 is reattached to the diagonal cable 3 near the unclealer 6.

Next, the diagonal cable 3 is gradually pulled up while rotating the uncoiler 6 again.

As a result, the diagonal cable 3 is pulled out from the unclealer 6 while removing the twist. In the same manner, the entire length of the coil-shaped diagonal cable 3 is pulled out from the unclealer 3.

When all the diagonal cables 3 are pulled out from the unclealer 6, the other end 3b of the diagonal cables 3 is taken by the tower crane 1.
And the other end 3b of the diagonal cable 3 is horizontally extended toward the fixing portion of the bridge girder 2 and fixed to the fixing portion of the bridge girder 2 to complete the erection work.

The rotation speed of the rotary pedestal 7 of the unreeler 6 can be freely controlled, and the tower crane 1 can be operated. The same applies to the case where a general cable, a continuous cable or the like is pulled out by a winch or the like, and it is possible to cope with a speed change of the winch or the like. Further, in this case, since the drive motor 9 is provided in the uncoiler 6, there is an advantage that the winch may be extremely small.

〔The invention's effect〕

The method for constructing the diagonal cable of the PC cable-stayed bridge according to the present invention is
With the above configuration, it has the following effects.

The diagonal cable wound in a coil is pulled out while rotating in the unwinding direction by a tower crane,
Moreover, since the cable is gradually pulled up while being rotated, the twist of the diagonal cable can be surely removed. In addition, the diagonal cable wound in a coil is not rotated by the force that pulls out the diagonal cable, but is placed on the pedestal of the unreeler and rotated by rotating this pedestal cable. Can be pulled out horizontally as well as upward. Therefore, a wide space is not required for the purpose of drawing out the diagonal cable, and the diagonal cable can be installed even in a narrow space.

Since the diagonal cable is pulled out only by the tower crane and the unloader, and no other heavy equipment such as a mobile crane or truck is used, it is easy to erect the diagonal cable even in a narrow space. Yes, it can be done safely.

[Brief description of drawings]

1 to 3 are partial side views of a PC cable-stayed bridge showing an embodiment of a method for constructing a diagonal cable of a PC cable-stayed bridge according to the present invention, and FIG. 4 is a PC cable-stayed bridge according to the present invention. It is a perspective view of an henler used for the method of constructing the diagonal cable of the tension bridge. 1 ... Main tower, 2 ... Bridge girder, 3 ... Cable cable, 4 ...
Tower crane, 5 ... Retractor, 6 ... Unreeler, 7 ... Rotating pedestal, 8 ... Pin rack, 9 ... Drive motor, 10 ... Sprocket, 11 ... Outer frame, 12 ... Inner frame,
13 …… Hanging jig, 14 …… Hook, 15 …… Pulling wire.

Claims (1)

[Claims] 1. A method for constructing a diagonal cable of a PC cable-stayed bridge, comprising a main tower, a bridge girder installed on the main tower, and a plurality of diagonal cables hanging the bridge girder on the main tower. A tower that bridges a diagonal cable wound in a coil shape in the direction of expansion of the diagonal cable and a bridge that spans the diagonal cable deployed from the uncoiler between the main tower and the bridge girder A crane is provided, and one end of the diagonal cable is pulled out by the tower crane while rotating the uncoiler in the developing direction of the diagonal cable, and is gradually pulled up while rotating to remove the twist of the diagonal cable. Next, one end of the diagonal cable is drawn into a fixing steel pipe attached to the main tower and fixed, and then a portion of the diagonal cable near the unloader is moved to the tower. The crane is hung up, and while being rotated, it is gradually pulled up to remove the twist of the diagonal cable, and after pulling out the entire length of the diagonal cable from the unreeler, the other end of the diagonal cable is removed by the tower crane. A method for constructing a diagonal cable of a PC cable-stayed bridge, characterized in that the cable is stretched and stretched in the direction of the fixing portion of the bridge girder and fixed to the fixing portion of the bridge girder.