JPH0650574Y2 - Unbonded PC cable rust prevention device for out cable - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] This invention is an unbonded PC cable used for a PC structure such as a bridge, and in particular, an unbonded cable used as an out cable.
The present invention relates to a rust preventive device in a fixing portion of a PC cable.

[Conventional technology]

PC structures designed with out cables to be placed on the outside of concrete are easy to repair in the future, do not require PC steel sheath placement and grout work, save labor and shorten construction time, reduce web thickness, etc. Have the advantage of.

By the way, as shown in Fig. 4, the PC cable of the PC bridge and the end of the fixing body designed with the OUT cable, which has a lot of experience in foreign countries, are placed inside the box girder 21 and are not directly exposed to wind and rain. Therefore, as shown in FIG. 5, the end of the unbonded PC cable or the out cable 20 using a plated steel stranded wire, etc. simply penetrates the concrete fixing projection 22 and is fixed by the fixing tool 23. Only. However, the fixing tool 23 may be covered with a rustproof cap 24 or the like. In addition,
In FIG. 4 (a), 26 is a deflecting portion of the cable, and 27 is a support for the bridge girder.

[Problems to be solved by the device]

Unbonded PC cables are generally equipped with grease and a plastic coating (plastic sheath) on the surface of PC steel. Therefore, when this unbonded PC cable is used as a tension steel material for applying stress to the structure, it is essential to peel off the plastic covering material in the vicinity of the fixing tool at least by an amount corresponding to the elongation of the steel material at the time of tension. This is because if the plastic covering material and the steel material are not allowed to move relative to each other in the longitudinal direction when the steel material is tensioned, the fixation of the steel material may fail.

However, if the plastic covering material is partially stripped off, the steel material in the part where the covering material is peeled off will corrode sooner, especially in the design of the out cable, unless some anticorrosive treatment is applied to the fixing tool and the steel material in its vicinity. However, depending on the case, it may be possible to disconnect.

The situation is the same for plated steel as the plated layer is damaged by the fixing tool.

Therefore, the cable behind the fixing tool in the fixing section is directly covered with concrete, or surrounded by an enclosure 25 such as a steel pipe or a sheath as shown in FIG. It is also practiced to fill the inner cavity with mortar. However, if such a method is adopted, it is impossible to replace the cable. Also, if a fluid material is used as the filling material of the cavity in the enclosure, the exchangeability of the cable is maintained, but in this case, it was difficult to seal the fluid filling material for a long period of time.

Therefore, the present invention intends to provide a rust preventive device in which a sealing structure of a fluid filler is devised in order to surely prevent corrosion of the out-cable fixing portion and maintain replaceability of the cable.

[Means for Solving the Problems]

The rust preventive device of this invention is one or more unbonded PCs.
In the fixing part of the unbonded PC cable for out cable composed of steel stranded wire, a cable insertion space defined by a non-water-permeable member is provided behind the fixing plate of the fixing tool sealed in the cap. The space between the cable inlets of the same number as the stranded wires installed at the end of the cable and the unbonded PC steel stranded wires passing through the individual inlets is sealed with an elastic sealing material that applies lateral pressure to seal the above space. In this closed space, the base end side of the portion of the unbonded PC steel wire from which the plastic covering material has been peeled off is arranged and a fluid anticorrosive agent is filled.

The elastic sealing material in this device is
Enclose the inlet side of the cable inlet with resin to block it from the outside air.

[Action]

As shown in Fig. 3 (a), the unbonded PC stranded wire is
It has a structure in which the PC strand 31 is covered and protected with a polyethylene sheath 32 and a grease 33 filling the polyethylene sheath 32, and a sufficient rust preventive function is exhibited in the sheath existing portion. However, B in FIG.
In the vicinity of the portion, the strand 31 is exposed as shown in FIGS. 3 (b) and 3 (c) by peeling off the sheath for fixing, so it is necessary to reliably isolate this exposed portion from the corrosive environment. In this device, since a rust preventive agent with a fluid is used instead of a solidifying material such as mortar for the isolation, the cable does not integrate with the concrete fixing protrusion,
A space is secured for pulling out and re-pulling the cable.

In addition, unbonded PC steel strands are passed through the individual inlets one by one, and at the inlets, the periphery of the sheath of the stranded wire is sealed with a pressurized elastic seal material. The rust preventive filling space that surrounds the base end side (peeling end of the coating material) is sealed with reliability, which prevents the flow of the fluid rust preventive agent as well as water from the outside. The inflow of corrosion factors is also reliably prevented.

Here, in the case of the device of the present invention, it becomes a problem how much the elastic seal material is optimally compressed and deformed. If this compression rate is too small, the possibility of outflow of the rust preventive agent due to injection pressure or static pressure during use increases, while if it is too large, compression set will occur within a short period of time, and the water blocking effect will be lost. Is. In an embodiment described later in which an O-ring is used as the elastic seal material, the compression rate is set to 30%. In this pressure resistance test at 30% compression, no water leaked from the O-ring portion even at a pressure of 6 kg / cm ² .

〔Example〕

An embodiment of this invention will be described with reference to FIGS. 1 and 2.

FIG. 1 shows a well-known fixing tool including a cylindrical main body 1a embedded in a concrete fixing protrusion 22, a fixing plate 1b which is applied to the outlet of the main body, and a taper cone 1c which is press-fitted into an eye hole of the fixing plate. Yes, the main body 1a and the grout cap 2 of this fixing device
Is joined to the abutting surface portion with a bolt through a rubber packing (not shown). 3 is a steel pipe connected to the main body of the fixing tool by screwing, 4 is a trumpet pipe connected to the steel pipe, and this pipe 4 and the embedding plate 5 placed at the inlet thereof, the trumpet pipe 4 and the steel pipe 3 are both The connecting portion is sealed with a sealing material such as tape.

Further, in front of the embedding plate 5, a cap 6 which is enlarged and shown in FIG. 2 is bolted by sealing the connection interface portion with a rubber packing 7. The cap 6 has a shape in which end wires are provided with the same number of twisted wire introducing ports 6a as the number of twisted wires 30 in which unbonded PC steel wires 30 are drawn one by one.

On the other hand, the rubber O-ring as the elastic seal member 8 is set in the ring groove 6b provided in the cap 6 on the inlet side of the twisted wire introducing port 6a, and the pressing plate 9 is attached to the outer surface of the end wall of the cap. It is elastically deformed at a compression rate of 30% by pressurizing with a bolt and is pressed against the sheath 32 of the unbonded PC steel wire 30 and the cap 6. This process is similarly performed for all of the unbonded PC steel strands constituting the cable.

Further, a resin box 10 is covered and covered with a rubber packing 11 in front of the cap 6, and the inner space of the box is filled with the resin 12 to cut off the contact of the O-ring 8 with the outside air. The arrangement of the resin 12 is effective in preventing the deterioration of the O-ring 8. 13 is a first spacer arranged at the entrance of the trumpet tube 4, and 14 is a second spacer arranged inside the tube.
Spacers have individual strands positioned through unbonded PC steel strands in the eyelets of these spacers.

Next, 15 is a closed space created behind the fixing plate 1b by the above device configuration, and a fluid rust preventive agent 16 such as grease is filled therein. Therefore unbonded PC steel strand
30 polyethylene sheath strips are made of this fluid rust inhibitor
Protected by 16, the grease flow in the polyethylene sheath 32 and the inflow of a corrosion factor into the polyethylene sheath 32 are surely prevented because the polyethylene sheath communicates with the closed space 15. The filling work of the fluid rust preventive material 16 may be performed by providing an openable inlet, an air outlet, etc., which are not shown, on the upper portion of the peripheral wall of the cap 6.

〔effect〕

As described above, the rust preventive device of the present invention creates a sealed cable insertion space behind the fixing plate in the fixing unit, fills it with a fluid rust preventive, and The cable inlet of this is a reliable seal between the sheath of the unbonded PC steel wire and the sheath of the stranded wire with an elastic sealant to prevent the outflow of the rust preventive agent. Rust prevention and corrosion prevention can be performed completely and stably for a long period of time without impairing cable exchangeability, which has many advantages in the design, construction and maintenance of PC structures. There is an effect that it can greatly contribute to

[Brief description of drawings]

FIG. 1 is an abstract sectional view showing an example of the rust preventive device of the present invention, FIG. 2 is an enlarged sectional view of the inlet side of the cable insertion space, and FIG. 3 (a) is an unbonded PC steel stranded wire. Figure 1A
3B is a sectional view taken along the line B of FIG. 1, and FIG. 3C is an enlarged view of the region B shown in FIG.
Fig. 4 (a) is a perspective view showing a part of a PC bridge designed with an out cable, and Fig. 4 (b) shows the rust preventive device of the present invention as shown in Fig. 4 (a). 5 is a cross-sectional view of a conventional fixing unit when added to FIG. 1 ... Fixing tool, 1a ... Main body, 1b ... Fixing plate, 1c ... Wedge, 2 ... Grout cap, 3 ... Steel tube, 4 ... Trumpet tube, 5 ... Embedding plate, 6 ... Cap, 6a: twisted wire inlet, 6b: ring groove, 7, 11 ... rubber packing, 8 ... elastic sealing material, 9 ... holding plate, 10 ... resin box, 12 ... resin, 13, 14 ... … Spacer, 15… Sealed space, 16… Fluid anticorrosive.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Creator Haruji Hirose 440-7 Higashitawara, Hadano City, Kanagawa Prefecture (7) (72) Creator Taiji Mikami 1-1-1 Kunyo Kita, Itami City, Hyogo Prefecture Sumitomo Electric Industries Itami Works Co., Ltd. (72) Inventor Shigeo Akasaki, Sumitomo Electric Industries, Ltd., 1-3-12 Moto-Akasaka, Minato-ku, Tokyo (56) Reference JP 62-125141 (JP, A) JP, U)

Claims (1)

[Scope of utility model registration request] 1. A member having no water permeation behind a fixing plate of a fixing tool sealed in a cap in a fixing portion of an unbonded PC cable for an out cable composed of one or a plurality of unbonded PC steel strands. The space for inserting the cable is drawn, and lateral pressure is applied to the gap between the cable inlets of the same number as the strands installed at the end of this space and the unbonded PC steel strands that pass through the individual inlets. Sealed with an elastic sealing material, further enclosing the inlet side of the cable introduction port with resin to shut off the elastic sealing material from the outside air to seal the space, and in the sealed space, the unbonded PC steel stranded wire plastic This is an unbonded PC cable rust preventive device for out cables, in which the base end side of the stripped coating is placed and a fluid rust preventive is filled.