JP2004353405A - Steel sheet pile anti-corrosive structure excellent in long-term durability - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a steel sheet pile anti-corrosive structure which prevents deterioration in a resin portion and degradation in adhesiveness in spite of long-term application, and formation of penetrating flaws etc. due to application of an impact, and exhibits excellent long-term durability. <P>SOLUTION: According to the steel sheet pile anti-corrosive structure, a high corrosion-resistant metallic plate is laminated on a surface of a steel sheet pile, that is to be corrosion-controlled, via an organic resin except for a claw portion, and after driving the steel sheet pile, the high corrosion-resistant metallic plate in the form that covers the claw portion is fixed to the claw portion to cover the same by a bolt structure while ensuring electrical insulation thereof from the steel sheet pile. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an anticorrosion structure made of steel sheet piles used for landfills on beaches, waste treatment facilities and seawalls of rivers and harbors, and more particularly, to a long-term anticorrosion structure when exposed to a severely corrosive environment. The present invention relates to an anticorrosion structure made of a steel sheet pile that ensures the above.
[0002]
[Prior art]
Marine steel structures such as steel pipe piles, steel pipe sheet piles, steel sheet piles, and the like used in severely corrosive environments are subjected to anticorrosion coating. Above all, heavy anticorrosion coating with a thickness of several mm is effective. When long-term durability for several decades is required, a heavy-duty anti-corrosion coating using a resin such as polyolefin or polyurethane, which is an inexpensive resin with excellent anti-corrosion properties such as electrical insulation and chemical resistance, is used. Steel materials are used.
Patent Documents 1, 2, and 3 disclose a method of attaching a titanium plate having a thickness of 0.01 to 0.1 mm on the above-mentioned polyolefin coating or polyurethane coating to improve the corrosion resistance and the adhesion durability. Is disclosed. Patent Literature 4 discloses a structure in which various corrosion-resistant metal plates are attached on a corrosion-resistant sheet and a method for preventing corrosion.
[0003]
[Patent Document 1]
JP 2001-47550 A [Patent Document 2]
JP 2001-113630 A [Patent Document 3]
JP 2001-260271 A [Patent Document 4]
Japanese Patent Application Laid-Open No. 2001-81583
[Problems to be solved by the invention]
Among the above anticorrosion techniques, those using a resin as a coating material have a life of about forty to fifty years due to the durability of the organic resin itself, and the adhesive force between iron and the resin also decreases with time. When the adhesive strength is reduced, the peeling proceeds from the end portion or the scratched portion of the coating, so that the corrosion gradually occurs in the portion where the iron base is exposed.
On the other hand, when the anticorrosion method of coating a high corrosion-resistant metal plate is applied to steel sheet piles used in coastal environments, if the high corrosion-resistant metal plate is covered up to the fitting portion of the claws, the high corrosion-resistant metal plate may be broken during casting. There is a possibility that the iron base and the highly corrosion-resistant metal plate will contact each other at that time, and the corrosion of the dissimilar metal, which is an electrochemical reaction, will occur, and the exposed iron base will be severely corroded, causing structural defects. There is.
[0005]
Therefore, the present invention solves the above-mentioned problems of the prior art of coating a high corrosion-resistant metal plate as an anticorrosion material, does not cause dissimilar metal contact corrosion, and ensures long-term corrosion resistance even when exposed to a severe corrosive environment. An object of the present invention is to provide an anticorrosion structure.
[0006]
[Means for Solving the Problems]
In order to solve the above problems, a steel sheet pile anticorrosion structure of the present invention having excellent long-term durability has the following structure.
(1) A steel sheet pile obtained by fitting a plurality of steel sheet piles in which a corrosion-resistant organic resin layer, an organic resin adhesive layer, and a highly corrosion-resistant metal sheet are sequentially laminated on a steel material surface by claws of the steel sheet pile. The structure is excellent in long-term durability, in which the entire corrosion-protected surface of the fitting portion is covered with a high corrosion-resistant metal plate in a state insulated from the steel sheet pile via an insulator. Steel sheet pile anticorrosion structure.
(2) Instead of the high corrosion-resistant metal plate covering the fitting portion, a fiber-reinforced plastic (FRP) having a high corrosion-resistant metal plate adhered to the surface or having a high corrosion-resistant metal film formed thereon is used. Steel sheet pile anticorrosion structure with excellent long-term durability.
[0007]
That is, the present invention provides a steel sheet pile formed by stacking a plurality of steel sheet piles formed by laminating a highly corrosion-resistant metal plate (A) on an anticorrosion surface excluding a claw portion via an organic resin adhesive layer with the claw portion. The steel sheet pile is provided with corrosion protection on the entire surface of the fitting section of the fitting section to prevent electrical conduction between the steel sheet pile to be subjected to corrosion protection and the highly corrosion-resistant metal member (B), thereby preventing dissimilar metal contact corrosion. In order to prevent this, a highly corrosion-resistant metal plate (B) is fixed with a bolt or the like via a resin insulator. An adhesive layer, a rubber seal layer, or a welded seam is provided to prevent corrosion factors such as water, oxygen, and chlorine from entering through a gap between the highly corrosion-resistant metal sheet (A) and the highly corrosion-resistant metal member (B) on the steel sheet pile. It is characterized by the following.
[0008]
BEST MODE FOR CARRYING OUT THE INVENTION
The steel sheet pile used in the present invention is provided with an anti-corrosion organic resin layer by applying an adhesive as necessary to the corrosion-protected surface excluding the claws of the steel sheet pile, and furthermore, a highly corrosion-resistant metal sheet (A ). FIG. 1 shows an example of the cross-sectional configuration. In the figure, 1 is a steel sheet pile, 2 is an anticorrosion organic resin layer, 3 is an adhesive layer, and 4 is a high corrosion resistant metal plate. FIG. 2 is a diagram showing an example of a structure for attaching a highly corrosion-resistant metal plate to a claw portion of a steel sheet pile. As shown in FIG. 2, a nut structure 5 is previously formed on the entire surface of the steel sheet pile claw to be protected. The inside of the nut structure is preferably filled with a soft filler 6 or the like in order to prevent corrosion during transportation or after casting. Here, when a steel sheet pile is used as a retaining wall for revetment, the surface to be protected refers to one surface facing seawater, not the soil side.
[0009]
Further, in the present invention, a high corrosion-resistant metal plate (B) having a shape covering a claw portion having a height centered on a wavy edge after the steel sheet pile is driven is sandwiched with a filling adhesive or a sealing agent made of an organic resin. Then, it is fixed with bolts via an electrical insulator. Such a long-term durable anticorrosion structure and a structure for forming such a structure are defined. FIG. 3 shows an example of a cross-sectional configuration of the structure. Reference numeral 7 denotes a highly corrosion-resistant metal plate (B), and reference numeral 8 denotes an organic resin adhesive filler or a rubber seal. Reference numeral 9 denotes a bolt to be connected to the nut structure 5. The bolt 9 is for fixing the highly corrosion-resistant metal plate 7, but is fixed via an insulating and anticorrosive resin 10 so as not to make electrical contact with each other. In the structural example of FIG. 3, since the high corrosion-resistant metal plate of 7 also requires strength, the thickness of the metal plate needs to be about 0.5 mm or more. Alternatively, if there is a problem in cost and rigidity of the highly corrosion-resistant metal plate, the method shown in FIG. 4 may be used. That is, 11 FRP (fiber reinforced plastic) is used as an insulating structure and a strength member, and a high corrosion resistant metal plate is pasted on the surface thereof or a metal thin film is formed. Since FRP functions as an insulating material, the insulating structure of 9 bolts can be omitted. Further, twelve anti-corrosion covers are provided to prevent corrosion of the bolts 9.
[0010]
In the present invention, a method for driving steel sheet piles is not specified, but care must be taken not to damage the highly corrosion-resistant metal sheet (A) previously coated. Furthermore, the high corrosion-resistant metal sheets (A) and (B) in the present invention are not particularly limited, but have a practically low corrosion rate in seawater, that is, 10 μm / year or less, and have crevice corrosion. It is preferable to use a stainless steel, a Ni-based corrosion-resistant alloy, or titanium having high corrosion resistance even in a seawater environment containing 2% or more of molybdenum. Further, it is desirable that the high corrosion-resistant metal plates (A) and (B) are the same type of metal. Further, the thickness of the highly corrosion-resistant metal plate is not particularly specified, but is preferably 0.1 mm or more and less than 1.5 mm. If the thickness is less than 0.1 mm, the metal plate often peels off during casting or the like, which is not practical. On the other hand, when the thickness exceeds 1.5 mm, workability is poor, and buckling or poor adhesion is likely to occur at a bent portion or the like. The thickness of the organic resin for bonding the high corrosion-resistant metal plate is not particularly specified, but it is essential that the high corrosion-resistant metal plate and the steel sheet pile base be electrically insulated. A thickness of 0.3 mm or more is desirable in order not to cause dielectric breakdown due to mechanical impact at the time of casting. In the case of a thicker member, it is desirable that the thickness be 5 mm or less because there is a balance between cost and durability. For the adhesive layer with the organic resin, for example, an adhesive such as a modified polyolefin, urethane, or epoxy resin is used. Further, in order to increase the thickness of the adhesive layer at low cost, it is possible to interpose a urethane elastomer or a foamable urethane resin layer.
[0011]
The present invention is not particularly limited as a method of attaching the high corrosion resistant metal cover after fitting to the claw portion. Therefore, instead of welding and fixing the nut to the steel sheet pile as shown in FIG. 2, a stud bolt may be welded to the steel sheet pile and fixed with the nut. However, in the method using stud bolts, care must be taken because the bolts are liable to be damaged during transportation. The high corrosion-resistant metal plates (A) and (B) have a structure sealed by an adhesive made of epoxy putty or a seal structure made of rubber, silicon, or the like. Welding may be performed. At this time, when the corrosion-resistant metal is titanium or seawater-resistant stainless steel, seam welding by electric heating, TIG welding, or the like can be applied. Further, it is desirable to inject an organic resin filler into the inside of the cover. When a filler is used, the penetration of water or oxygen from the upper and lower ends of the cover can be suppressed, so that the durability life is greatly increased.
[0012]
【Example】
Hereinafter, the present invention will be described in detail with reference to Examples.
U-type steel sheet pile of JIS standard SY295, 10m long, 3m part corresponding to the tidal zone is grid blasted, scale is removed, etc. Then, two-part mixture-curable urethane resin with polyol and isocyanate curing agent as primer The paint was spray-coated to a thickness of 15 to 60 μm and cured. Next, a two-component curable urethane elastomer containing fine kaolin clay powder was mixed with a mixer on the surface thereof, spray-coated, and a 3 mm-thick polyurethane heavy anticorrosion coating was performed. Thereafter, a thermosetting isocyanate-curable urethane resin was applied to the surface, and in a semi-cured state, a 0.3 mm-thick titanium plate was adhered to the surface while being pressed with a roll. The attached surfaces are three convex surfaces of steel sheet pile and two concave surfaces. One of the concave steel sheet piles was previously provided with a nut structure shown in a cross section in FIG. 2 at a pitch of 20 cm on the claws, and the other was not provided with a nut structure as a comparative example. These were cast at a test location on the beach with a bible hammer, and one side of the nail to which the nut was welded was coated with a highly corrosion-resistant metal by the bolt fixing structure of the present invention in the structure of FIG. 3 on one side. The other side was covered with a fixing structure using the FRP shown in FIG. The upper and lower ends of the highly corrosion-resistant metal plate (B) were completely sealed with an epoxy filler to prevent water from entering. For comparison, the claw portions where the nuts were not welded were the cases where a high corrosion resistant metal plate was bonded and fixed with an adhesive filler without providing a bolt fixing structure and where the corrosion resistant metal was not coated.
[0013]
Six months after the construction, changes in the appearance were observed. In the untreated nail portion of the comparative example, rust was generated in a portion where the coating did not reach. In the case where the corrosion-resistant metal is fixed only with the adhesive without using the bolt, the end of the corrosion-resistant metal cover at the fitting portion has a floating. Further, when the corrosion-resistant metal plate (B) was removed by inserting a chisel at the end, it could be easily peeled off. However, no corrosion was observed in the claws under the corrosion-resistant metal coating. In the other examples of the present invention, no lifting occurred, the appearance was extremely good, and at the same time, the bolt could not be peeled off without removing the bolt even if a chisel was inserted into the end. In addition, even when the observation was performed in a state where the highly corrosion-resistant metal plate was removed by removing the bolts, no corrosion was observed including the nut portion, and the state was sound, thus demonstrating the effect of the present invention.
[0014]
【The invention's effect】
According to the present invention, it is possible to manufacture a steel sheet pile revetment having beautiful and long-term durability performance. In addition, since the fitting portion, which has not been coated in the conventional heavy-duty corrosion protection, is excellent in long-term durability, it is possible to reduce the maintenance cost.
[Brief description of the drawings]
FIG. 1 is a cross-sectional example of anticorrosion of a steel sheet pile convex surface before casting according to the present invention.
FIG. 2 shows an example of a corrosion prevention cross-section and a fixing structure of a steel arrow concave surface before casting according to the present invention.
FIG. 3 is a cross-sectional example of a fitting portion of an anticorrosion structure using a highly corrosion-resistant metal plate (B) of the present invention.
FIG. 4 is a cross-sectional example of a fitting portion of an anticorrosion structure using a composite of a highly corrosion-resistant metal plate (B) of the present invention and FRP.
[Explanation of symbols]
1: Steel sheet pile 2: Organic resin anticorrosion layer 3: Organic resin adhesive layer 4: High corrosion resistant metal plate (A)
5: Nut structure 6: Organic resin filler 7: High corrosion resistant metal plate (B)
8: Filling adhesive or rubber seal 9: Bolt 10: Electrical insulation structure 11: FRP
12: Anticorrosion cap

Claims (2)

A steel sheet pile structure in which a plurality of steel sheet piles formed by sequentially laminating a corrosion-resistant organic resin layer, an organic resin adhesive layer, and a high-corrosion-resistant metal sheet on a steel material surface are fitted with claws of the steel sheet pile. A corrosion-resistant steel sheet pile with excellent long-term durability, wherein a high corrosion-resistant metal sheet is coated on the entire corrosion-protected surface side of the fitting portion while being insulated from the steel sheet pile via an insulator. Structure. In place of the high corrosion-resistant metal plate covering the fitting portion, a fiber-reinforced plastic (hereinafter, referred to as FRP) having a high corrosion-resistant metal plate adhered to the surface or having a high corrosion-resistant metal film formed thereon is used. The steel sheet pile anticorrosion structure having excellent long-term durability according to claim 1.

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