JP3049454B2 - Tension fixing device and fixing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fixing device and a fixing method for tensioning a cable. Further, the present invention relates to a fixing device and a fixing method for fixing a bridge girder of a cable stayed bridge and a cable supporting a bridge girder of an external cable.

[0002]

2. Description of the Related Art A cable supporting a bridge girder of a cable-stayed bridge is fixed to the bridge girder by a fixing device. The fixing cylinder of the fixing device is tightly fixed to the sheath so as to prevent rainwater or the like from entering the fixing cylinder in order to protect the PC steel material from which the sheath has been peeled. When the PC steel material is pulled by the jack in the fixing operation, the cable has a structure in which the PC steel material and the sheath do not adhere to each other so as not to be drawn into the sheath.

[0003]

Problems to be Solved by the Invention There are the following problems in the above-mentioned conventional device. A cable in which a PC steel material and a sheath are in close contact cannot be used. If this closely attached cable is used, when the PC steel material is pulled by the jack, it is pulled to the sheath and attempts to approach the anchor head. However, since the fixed cylinder is fixed to the sheath, it prevents the sheath from approaching the anchor head. As a result, there is a problem that stress is applied to the fixed cylinder, the fixed cylinder is damaged, and the exposed PC steel rusts.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a fixing device and a fixing method which can be used even for a cable whose sheath is in close contact with a PC steel material.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a tension fixing device for fixing a cable covered with a sheath, an anchor head having a plurality of through holes through which a PC steel material of the cable penetrates, and an anchor head having a plurality of through holes. It has a fixed cylinder attached, and a slide cylinder that is concentric with, close to, and slidable from the fixed cylinder, a cable passes through the inside of the fixed cylinder and the slide cylinder, and the sheath and the slide cylinder are sealed. It is fixed, and is covered with a sheath using a tension fixing device characterized in that an internal space formed by the fixed cylinder and the slide cylinder is sealed, and a tension fixing device having an anchor head. In a fixing method for tensioning a cable, a step of penetrating a PC steel material of a cable into a plurality of through holes formed in the anchor head, and attaching the cable to the anchor head. A step of hermetically fixing a slidable slide cylinder to the sheath while closely contacting the fixed cylinder, and a step of jacking a PC steel material penetrating the anchor head with a jack to tension the cable, The fixing method is characterized in that the slide tube slides with respect to the fixed tube with the movement of the sheath due to the tension, approaches the anchor head, and unnecessary stress is not applied to the sheath.

[0006]

Embodiments of the present invention will be described below with reference to the drawings. The configuration of the tension fixing device will be described with reference to FIG. In order to support the bridge girder of the cable-stayed bridge and the bridge girder of the outer cable, a number of slanted cables are stretched from the main tower to the left and right. One end of the oblique cable is fixed to the bridge girder by a tension fixing device. FIG. 1 shows a detailed view of the tension fixing device.

<A> Anchor head The anchor head 1 is screwed by a ring nut 20 fixed to the support plate 7. The anchor head 1 fixes the PC steel 3 of the cable 2. For this purpose, the through holes 4 for penetrating the PC steel 3 are provided by the number of the PC steel 3. Each PC steel material 3 penetrates through the through hole 4 and is fixed to the anchor head 1 by a wedge 6.
A plate 13 is provided to prevent the wedge 6 from coming off. In addition, a protective cap 11 is attached to the anchor head 1 to protect the end of the PC steel 3. An oil injection and exhaust port 12 is provided to fill the protective cap with the rust-preventive oil 21.

<B> Fixed Tube and Slide Tube The fixed tube 8 and the slide tube 9 are for protecting the PC steel 3 whose cable 2 is exposed from the sheath 10 from rust and the like. The fixed cylinder 8 is fixed to the anchor head 1 and forms a double cylinder concentrically with the slide cylinder 9. Slide tube 9
Are slidable and close to the fixed cylinder 8, and are configured so that the rust-preventive oil 21 does not leak. Specifically, the fixed barrel 8 is provided at one end of the fixed barrel 8, whereby the fixed barrel 8 is brought into close contact with the slide barrel 9. A fastening ring 14 is provided at an end of the slide cylinder 9 so that when the PC steel 3 is attached to the anchor head 1, the PC steel 3 is not broken even if the PC steel 3 is expanded. It holds down the spread of 3 . Further, at the end of the slide cylinder 9, the exposed PC steel 3
And is fixed so as to be in close contact with the sheath 10 so that rainwater or the like does not enter the inside. The space covered by the anchor head 1, the fixed cylinder 8, the slide cylinder 9, and the protective cap 11 is filled with rust-preventive oil 21. As a result, the PC steel material 3 becomes the sheath 1
The part exposed from 0 is protected by the rust-preventive oil 21.

<C> Casing and Boot To protect the fixed cylinder 5 and the slide cylinder 9, a casing 24 and a boot 23 are provided so as to cover them. The casing 24 is attached to the anchor head 1 via the support plate 7, and the boot 23 is attached to the end of the casing 24 and the sheath 10.

A method of tensioning and fixing the cable 2 will be described with reference to FIG. <A> Fixing of the tip of PC steel material PC steel material 3 that has passed through through hole 4 of anchor head 1 is fixed to through hole 4 by wedge 6. Further, the PC steel material 3 penetrating the anchor head is fixed to the pulling head 16 via the center hole jack 15. The fixing method to the pulling head 16 is as follows: holes are provided in the pulling head 16 by the number of PC steel materials, and after the PC steel material is penetrated, the wedge 1 is formed.
7 is inserted into each hole and fixed. The center hole jack 15 is fixed to the support plate 7 by a jack chair 26.

<B> Tension of PC Steel by Jack The oil is injected into one of the oil injection and discharge ports 25 to apply hydraulic pressure to the jack 15, and the piston 18 is extended. As a result, the cylinder 19 pushes the bearing plate 7 while the piston pushes the pulling head 16. Accordingly, the PC steel 3 is tensioned, and together with it, the sheath 10 is pulled in the direction of the anchor head 1. The wedge 6 is inserted into the through hole 4 of the anchor head 1.
Are arranged in the loosening direction, so that the PC steel material 3 is easily tensioned. The slide cylinder 9 fixed to the sheath 10
The sheath 10 slides in the direction of the anchor head 1 as the sheath 10 moves. Therefore, the exposed PC steel material 3 is always in a sealed state, and stress is not applied to the sheath 10.

<C> Installation of the protective cap After the tension of the PC steel material 3 is finished, the center hole jack 15 is removed, and the PC steel material is cut leaving a predetermined length. A protection cap 11 is attached to the anchor head 1 so as to cover the PC steel 3. The rust prevention oil 21 is filled from the oil inlet / exhaust port 12 of the protection cap 11, and the fixed cylinder 8, the slide cylinder 9 and the protection cap 11 are filled with the oil 21.

[0013]

Since the present invention has been described above, the following special effects can be obtained. Cable P
Since the cylinder for shielding the C steel material from the outside is doubled and slidable, a cable in which the PC steel material and the sheath are in close contact can be used, and a special effect such as rust prevention of the PC steel material is produced.

[Brief description of the drawings]

FIG. 1 is a diagram of a tension fixing device.

FIG. 2 is a view of tensioning a cable.

Claims (2)

(57) [Claims] 1. A tension fixing device for fixing a cable covered with a sheath, an anchor head provided with a plurality of through holes through which a PC steel material of the cable passes, a fixed cylinder attached to the anchor head, and the fixing A sliding cylinder concentrically in contact with the cylinder and slidable, a cable penetrating through the fixed cylinder and the sliding cylinder, the sheath and the sliding cylinder are hermetically fixed, and the fixed cylinder and the sliding cylinder are fixed to each other. A tension fixing device, wherein an internal space formed by a cylinder is sealed. 2. A fixing method for tensioning a cable covered with a sheath using a tension fixing device having an anchor head, wherein a PC steel material of the cable is passed through a plurality of through holes formed in the anchor head. And a step of hermetically fixing a slide tube slidable in close contact with the fixed tube attached to the anchor head to the sheath, and tensioning the cable by pulling a PC steel material penetrating the anchor head with a jack. And a step of causing the slide tube to slide with respect to the fixed tube with the movement of the sheath due to the tension, approaching the anchor head, and applying unnecessary stress to the sheath.