JP3855039B2 - Corrosion protection structure near saddle part of suspension bridge cable and its construction method. - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an anticorrosion structure in the vicinity of a saddle portion of a suspension bridge cable and its construction method, which require high corrosion resistance over a long period of time.
[0002]
[Prior art]
The cable anticorrosion method in the vicinity of the saddle portion of the suspension bridge cable is to wrap a steel plate formed into a cylindrical shape with an inner diameter larger than the outer diameter of the cable around the cable, and to engage the ends in the longitudinal direction and the circumferential direction with bolts or sealing materials. A cover system that stops and seals is common.
[0003]
[Problems to be solved by the invention]
In such a conventional steel plate cover cable anticorrosion method, in long-term exposure, it is easy to create a gap due to corrosion of the bolts that lock the end of the cover or deterioration of the sealant, from there water and moisture, Since corrosive factors such as corrosive gas penetrate, it is not a sufficient anticorrosion method for preventing cable corrosion.
[0004]
The present invention provides a saddle portion for a suspension bridge cable that can be reliably protected over a longer period of time than a corrosion prevention method using a steel plate cover by coating the surface of the cable near the saddle portion of the suspension bridge cable with an anticorrosion resin such as polyurethane resin. The object is to provide a nearby anticorrosion structure and anticorrosion method.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the saddle part vicinity anticorrosion structure of the suspension bridge cable according to the present invention and its construction method, as shown in FIGS. 1 to 5, the cable 2 has a hexagonal cross section on the saddle part 1 side. However, the cable band 3 side is substantially circular. In the present invention, the surface of the cable 2 in the vicinity of the saddle portion 1 of the suspension bridge cable is covered with the shielding sheet 12, and then the detachable tubular cover 14 that forms the gap 24 via the spacers 21 and 22 is formed thereon. After attaching and sealingly sealing the circumferential end of the tubular cover 14 and the longitudinal front and rear ends thereof, the anticorrosive resin 13 is injected into the gap 24 from the injection port 14 c provided in the tubular cover 14. After the curing, the tubular cover 14 is removed to form an anticorrosion layer. FIG. 2 shows a cross section during the anticorrosion construction immediately near the saddle portion, and FIG. 3 shows a cross section during the anticorrosion construction on the cable band side.
[0006]
As shown in FIG. 5, the tubular cover 14 is provided with a locking portion 14 a along the longitudinal direction at a side end in the circumferential direction so as to be openable along the longitudinal direction, and the locking portion 14 a is tightened with a jig. The opening is hermetically sealed by fastening at 14b. As a material of the tubular cover 14, it is preferable to use a fiber reinforced plastic having elastic deformation and excellent dimensional stability.
[0007]
The anticorrosion resin 13 is a polyurethane resin. Furthermore, the spacers 21 and 22 that hold the gap 24 between the blocking sheet 12 and the tubular cover 14 are preferably made of a material that has anticorrosive properties and can be bonded to the anticorrosive resin 13 and is embedded as an integral anticorrosive resin. .
[0008]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
In the present invention, the anticorrosion resin 13 to be coated on the cable surface is a liquid that can be injected into a narrow space before curing, and has a certain degree of flexibility after curing and also has corrosion resistance and weather resistance. There is a need. As a material satisfying these conditions, a polyurethane resin obtained by mixing a main agent and a curing agent is most preferable, but other than this, a polyethylene resin, an epoxy resin, or the like may be used.
[0009]
When covering the anticorrosive resin 13, after covering the surface of the cable with the blocking sheet 12, a removable tubular cover 14 that holds the gap 24 is attached via the spacers 21 and 22. After sealing and sealing the circumferential side end and the longitudinal front and rear ends, the anticorrosive resin 13 is injected into the gap 24 from the injection port 14c provided in the tubular cover 14 to prevent corrosion on the cable surface. Resin 13 is coated. At this time, the air in the gap 24 is discharged from the air vent 14d.
[0010]
After the anticorrosive resin 13 is cured, the cable cover 2 in the vicinity of the saddle portion 1 can be formed with a coating layer having a constant coating thickness by removing the tubular cover 14. An excellent coating can be realized easily and accurately.
[0011]
The blocking sheet 12 used in the present invention is intended to prevent the anticorrosive resin 13 from entering the inside of the cable, preferably has a blocking property, is not affected by the anticorrosive resin 13, and is easy to construct. Examples thereof include a polyethylene tape and a heat-shrinkable polyethylene sheet.
[0012]
When covering the shielding sheet 12, the cross-sectional shape of the cable on the saddle 1 side is hexagonal, so that a gap is generated between the shielding sheet 12 and the cable surface. By embedding a filler such as butyl rubber in the gap, it is possible to prevent condensation in the gap.
[0013]
As shown in FIG. 5, the structure of the tubular cover 14 used in the present invention is characterized in that it can be opened along the longitudinal direction and has a tongue-like locking portion 14 a at the circumferential end. It is.
[0014]
As a method for locking the tubular cover 14, there is a method in which a cushion material (not shown) is sandwiched in the locking portion 14 a at the circumferential side end and tightened with a tightening jig 14 b such as a U-shaped clamp. The material of the tubular cover 14 is elastically deformable, and is preferably fiber reinforced plastic in terms of dimensional stability, strength, workability, and lightness. Other than that, a steel plate, a galvanized steel plate, a stainless steel plate are used. An aluminum plate or the like can also be used. In this case, it is necessary to set the plate thickness and material so that elastic deformation can be performed beyond the outer diameter of the cable.
[0015]
The tubular cover 14 used in the present invention is required to be easily removable after the injected anticorrosive resin 13 is cured. Therefore, it is preferable to perform adhesion prevention treatment such as application of a release agent and Teflon processing so that the anticorrosive resin 13 does not adhere to the inner surface of the tubular cover 14.
[0016]
In addition, the spacers 21 and 22 that hold the gap 24 between the cable surface 23 covered with the shielding sheet 12 and the inner surface of the tubular cover 14 have a corrosion resistance and are made of a material that can be bonded to the corrosion resistance resin 13. It is desirable to embed it integrally with the anticorrosion resin 13. When a polyurethane resin is selected as the anticorrosive resin 13, a polyurethane resin piece prepared in advance is used for the spacers 21 and 22.
[0017]
In addition, when the anticorrosion construction range is long, the spacers 21 and 22 are not only at both ends but also at the intermediate portion so as to keep the gap 24 between the cable surface 23 covered with the shielding sheet 12 and the inner surface of the tubular cover 14 constant. It may be arranged appropriately.
[0018]
6 to 8 are examples in which the end portion of the anticorrosion layer coated according to the present invention is finished, FIG. 6 is an example of processing a joint portion with the cable band 3, and FIGS. 7 and 8 are joint portions with the saddle 1. Are two processing examples. For finishing, the sealing material was made of two non-adhesive layers, the inner layer 41 was made of a material that could be filled into a narrow gap, and a polyurethane water-stopping material that could be constructed with a caulking gun was used. The outer layer 42 has excellent weather resistance and is made of a material having excellent adhesion to the saddle, the end band, the steel collar 44 and the polyurethane coating layers 21 and 22, and a two-component modified silicon caulking material is used. The reason why the two sealing materials are not bonded is to prevent the triangular joint and the three-surface bonding that the caulking is easily peeled off. Therefore, a blocking layer 43 made of film-like polyethylene is provided.
[0019]
【Example】
Example 1
As a specific embodiment of the present invention, an example in which a cable near the saddle portion of a suspension bridge cable having a length of 2100 mm is coated with a two-component curing type polyurethane resin will be described.
[0020]
In the vicinity of the saddle portion of the cable, as shown in FIG. 1, the cross-sectional shape of the cable 2 on the saddle 1 side is a hexagonal shape with a step of 518 mm in the horizontal direction and 516 mm in the vertical direction, and the cross-sectional shape on the cable band 3 side is The diameter was 470 mm.
[0021]
After filling the step on the saddle side with butyl rubber, the cable surface was covered with a polyethylene sheet. Covering method: Heat-shrinkable polyethylene sheet with a width of 900 mm and a thickness of 1 mm is wrapped around the cable surface with a wrap of 100 mm or more, the end in the longitudinal direction is stopped with a polyethylene heat seal, and then heat-shrinked. Fit on the surface. The above operation was sequentially repeated, and the entire surface of the cable was covered with a heat-shrinkable polyethylene sheet. Also, the wrapped circumferential end was sealed with a butyl rubber material.
[0022]
Next, as shown in FIG. 9, polyurethane is formed in advance using a two-component curable polyurethane resin paint, and spacers are formed on both ends of the cable-side saddle side and cable band side of the cable coated with the polyethylene sheet. It fixed using the adhesive agent 33 which has resin as a main component.
[0023]
Next, a fiber reinforced plastic tubular cover 14 having a release agent coated on the inner surface and capable of opening in the longitudinal direction and having a locking portion at the side end in the longitudinal direction is attached. It was. A 10 mm diameter polyurethane resin paint inlet 14 c is provided at the lower part of the tubular cover 14, and an air vent 14 d is provided at the upper part of the tubular cover 14.
[0024]
The locking portion 14a at the circumferential side end of the tongue-like shape of the tubular cover 14 was clamped with a cushioning material 14b such as a U-shaped clamp. As shown in FIG. 9, the front and rear end portions of the tubular cover 14 were fixed with a steel fastening belt 32 after being wound with a tape 31.
[0025]
Before injection of the resin paint, it was confirmed whether there was any leakage by applying a pressure corresponding to the injection paint pressure from the paint injection port 14c with the air vent 14d closed.
[0026]
Thereafter, the air vent 14d was opened, and a two-component curable polyurethane resin paint was poured from the paint inlet 14c, and it was confirmed that the paint was filled from the air vent 14d above the cable.
[0027]
After curing and curing of the polyurethane resin paint, the tubular cover 14 was removed.
The outer appearance of the cable obtained by the above method was good, and no defects that impair the film properties were found. In addition, the spacers installed on the saddle side of the cable and both ends of the cable band were also embedded as a single piece in the coating resin and had good adhesion.
Moreover, about the coating layer, the film thickness distribution and the inspection evaluation by a pinhole test were also performed. As a result, the film thickness was distributed within 15% of the design value, and there was no problem. Further, no pinhole was detected even in a 10 kV pinhole test, and a coating layer having good quality performance was formed.
[0029]
【The invention's effect】
As described above, the anticorrosion structure in the vicinity of the saddle portion of the suspension bridge cable and the construction method thereof according to the present invention cover the surface of the cable 2 in the vicinity of the saddle portion of the suspension bridge cable with the blocking sheet 12, and then the spacer 21 from above. , 22 is attached to the tubular cover 14 to form a gap 24, and the circumferential end of the tubular cover and the front and rear ends in the longitudinal direction are hermetically sealed, and then the tubular cover 14 is provided. Since the anticorrosive resin 13 is injected into the gap 24 from the injection port 14c and cured, the tubular cover 14 is removed to form an anticorrosion layer, so that a conventional anticorrosion method using a steel cover is provided. It is possible to provide a coating that can reliably prevent corrosion over a longer period of time.
[Brief description of the drawings]
FIG. 1 is a conceptual diagram showing a structure in the vicinity of a saddle portion of a suspension bridge cable in a perspective view.
FIG. 2 is a cross-sectional view of the cable during the anti-corrosion construction right near the saddle portion of the present invention.
FIG. 3 is a cross-sectional view of the cable during the anticorrosion work on the cable band side of the present invention.
FIG. 4 is a partially cutaway side view illustrating a structural example of a coating apparatus used for carrying out the present invention.
FIG. 5 is a perspective view of a tubular cover that can be opened in the longitudinal direction and can be locked at an end in the longitudinal direction according to the present invention.
FIG. 6 is an enlarged partial cross-sectional view of an example of finishing treatment of the cable band side end of the anticorrosion layer coated according to the present invention.
FIG. 7 is an enlarged partial cross-sectional view of a first finishing treatment example of the saddle side end of the anticorrosion layer coated according to the present invention.
FIG. 8 is an enlarged partial cross-sectional view of a second finishing example of the saddle side end of the anticorrosion layer coated according to the present invention.
FIG. 9 is a conceptual diagram of a front and rear end structure of a tubular cover, illustrating a saddle side as an example.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Saddle of suspension bridge 2 Cable near saddle part 3 Cable band 4 Cable general part 12 Barrier sheet 13 Anticorrosive resin 14 Tubular cover 14a Side end latching part 14b of tubular cover Side end latching jig 14c of tubular cover Inlet 14d Air vent 21 Spacer (saddle side)
22 Spacer (cable band side)
23 Cable surface covered with shielding sheet 24 Clearance 31 inside tubular cover 31 Tape 32 Steel fastening belt 33 Adhesive 41 mainly composed of polyurethane resin Inner layer sealing material 42 Outer layer sealing material 43 Film-like shielding layer 44 Steel Color

Claims (7)

The surface of the cable 2 in the vicinity of the saddle portion of the suspension bridge cable is coated with a corrosion prevention layer via the shielding sheet 12, and this corrosion prevention layer is attached to the cable 2 via the spacers 21 and 22 from above the shielding sheet 12. A saddle portion of a suspension bridge cable, which is formed by an anticorrosive resin 13 filled and cured through the inlet in a sealed gap inside the tubular cover 14 which is arranged and has an inlet and an outlet. Neighborhood anticorrosion structure. After the surface of the cable 2 in the vicinity of the saddle portion of the suspension bridge cable is covered with the shielding sheet 12, a detachable tubular cover 14 that forms the gap 24 is attached via the spacer sheet 21 and 22 from above. The front and rear end portions and the side end portions of the tubular cover 14 are hermetically sealed, the anticorrosive resin 13 is filled and cured in the gap 24 through the inlet and outlet provided in the tubular cover 14, and then the tubular cover 14 is removed. An anticorrosion construction method in the vicinity of a saddle portion of a suspension bridge cable characterized by forming an anticorrosion layer. The tubular cover (14) is provided with a locking portion (14a) along a longitudinal direction at a side end in a circumferential direction so that the tubular cover (14) can be opened, and the opening is hermetically sealed by a tightening jig (14b). Corrosion prevention construction method near the saddle part of the suspension bridge cable described. The locking portion 14a along the longitudinal direction of the circumferential side end of the tubular cover 14 is made of fiber reinforced plastic that can be elastically deformed and opened beyond the outer diameter of the cable. Or the saddle part vicinity anticorrosion construction method of the suspension bridge cable of 3 description. The saddle part vicinity anticorrosion construction method of the suspension bridge cable according to any one of claims 2 to 4, wherein an adhesion preventing process is performed on an inner surface of the tubular cover 14. 6. The method for preventing corrosion near a saddle portion of a suspension bridge cable according to claim 2, wherein the anticorrosive resin 13 filled in the gap 24 between the tubular cover 14 and the shielding sheet 12 is a polyurethane resin. The spacers 21 and 22 that hold the gap 24 between the tubular cover 14 and the shielding sheet 12 are made of a material that is anti-corrosive and can be bonded to the anti-corrosive resin 13. After the anti-corrosive resin 13 is cured, the anti-corrosion The saddle part vicinity anticorrosion construction method of the suspension bridge cable in any one of Claims 2-6 characterized by being embedded as integral with the functional resin 13. As shown in FIG.

Images