JP6823510B2 - Anti-corrosion structure of steel pipe sheet pile - Google Patents

Description

The present invention relates to an anticorrosion structure for steel pipe sheet piles.

Steel pipe sheet piles used as at least a part of existing structures such as marine structures and river structures are easily corroded, and the degree is remarkable especially in a splash zone and a tidal zone.
Therefore, conventionally, a method of installing an anticorrosion structure on the surface of a steel pipe sheet pile to prevent corrosion has been applied. As one of such anticorrosion methods, a method of installing an anticorrosion structure by forming an anticorrosion layer made of an organic resin or the like on the surface of a steel pipe sheet pile and further adhering and fixing a corrosion-resistant metal thin plate on the surface. Are known.
By applying such an anticorrosion treatment, it is possible to impart long-term anticorrosion properties to the existing structure as described above. Further, if the anticorrosion layer is formed by using a fiber reinforced resin or a foamed resin, it is possible to impart environmental blocking property and impact resistance.
Such anticorrosion methods are described in, for example, Patent Documents 1 to 3.

A conventional anticorrosion structure will be described with reference to FIG.
FIG. 3 is an outline showing a state in which a steel pipe sheet pile 1 which is a part of an offshore structure is installed on a revetment G, and a conventional anticorrosion structure 2 is attached to the sea S side (outside) of the steel pipe sheet pile 1. It is a sectional view.
The side where water such as seawater exists with respect to the steel pipe sheet pile 1 is also referred to as "outside", and the opposite side is also referred to as "inside". Therefore, in the case of the aspect shown in FIG. 3, the sea S side is "outside" and the opposite side is "inside" with respect to the revetment G.

In FIG. 3, the steel pipe sheet pile 1 has a main body portion 11 having a semicircular cross section formed of a long tubular steel material, and a connecting portion 12 arranged so as to be sandwiched between the two main body portions 11. A wall-like structure (existing structure) is formed by connecting the main body portion 11 with the connecting portion 12.
Further, the connecting portion 12 is formed by connecting a female connecting portion 122 made of angle steel having an L-shaped cross section and a male connecting portion 121 made of two T-shaped steels having a T-shaped cross section. Such a connecting portion is generally called an LT type. In the aspect shown in FIG. 3, it is LT type, but as another connecting portion, it is composed of two pipes, a part of one pipe in the circumferential direction is cut, and the other pipe is charged into this cut portion. There are known PT type and PT type in which a pipe and T-shaped steel are connected.

The anticorrosion structure 2 shown in FIG. 3 includes an anticorrosion layer 25 formed on the surface of the steel pipe sheet pile 1, a cushion layer 27 on the outside thereof, and a corrosion resistant metal plate 3 on the outside thereof. The corrosion-resistant metal plate 3 is divided into two parts and joined to each other at the central flange portion 31 by using bolts 33 and nuts 35. In order to cope with the dimensional error of the joint portion that may occur at the time of casting, it is necessary that the corrosion-resistant metal plate 3 is divided into two and joined by the flange portion 31.
Then, the anticorrosion layer 25, the cushion layer 27, and the corrosion-resistant metal plate 3 are fixed by the fixing means 4 so as to be in close contact with the surface of the steel pipe sheet pile 1. The fixing means 4 includes a fixing plate 41, a bolt 44, a washer 45, and a nut 47. The fixing plate 41 is welded and fixed to the surface of the connecting portion 12 (female connecting portion 122). Further, the bolt 44 is fixed to the fixing plate 41 and projects toward the sea S side. Then, the bolt 44 is inserted into the insertion hole provided at the end (flat portion 37) of the corrosion-proof layer 25, the cushion layer 27, and the corrosion-resistant metal plate 3, and the bolt 44 is further inserted into the insertion hole of the washer 45 from the sea S side. Then screw the nut 47.
By adjusting the degree of tightening between the bolt 33 and the nut 35 at the time of driving, the degree of adhesion of the corrosion-resistant metal plate 3 to the surface of the steel pipe sheet metal plate 1 is adjusted.

Japanese Unexamined Patent Publication No. 2013-289949 JP 2015-194215 Jikkenhei 6-1991

In the conventional anticorrosion structure as described above, the amount of tightening at the flange portion 31 becomes inappropriate depending on the skill level of the builder at the time of placing the structure, and the surface of the steel pipe sheet pile 1 of the anticorrosion structure In some cases, the degree of adhesion was insufficient. In addition, the degree of adhesion of the anticorrosion structure to the steel pipe sheet pile is insufficient due to the dimensional error caused by the expansion and contraction of the joint part that occurs during casting and the effect of the steel pipe sheet pile thinning with the passage of time after driving. There was a case that it ended up. Furthermore, the flange may be damaged due to collision of drifting objects such as driftwood and drift ice with the flange, or the influence of waves, and the degree of adhesion of the anticorrosion structure to the surface of the steel pipe sheet pile may be insufficient. It was.

INDUSTRIAL APPLICABILITY According to the present invention, the anticorrosion structure can be brought into close contact with the steel pipe sheet pile even if the degree of skill of the builder is low at the time of casting and even if the wall thickness is reduced due to corrosion after casting. It is an object of the present invention to provide an anticorrosion structure that is not easily damaged by an external force such as collision of drifting objects such as driftwood and drift ice and waves because there is no flange portion.

The present inventor studied diligently, found a method for solving the above problems, and completed the present invention.
The present invention is the following (1) to (4).
(1) An anticorrosion structure including at least an anticorrosion layer and a corrosion-resistant metal plate formed on the surface of a steel pipe sheet pile that is a part of an existing structure, and fixing means for fixing these to the steel pipe sheet pile.
The corrosion-resistant metal plate includes a main body portion having a bellows structure portion at least partially covering the main body portion having a semicircular cross section of the steel pipe sheet pile, and a flat portion formed on the edge of the main body portion.
An anticorrosion structure configured to be in close contact with the surface of the steel pipe sheet pile by contracting the bellows structure portion at the time of driving and after driving.
(2) The fixing means includes a fixing plate fixed to the steel pipe sheet pile, a bolt fixed to the fixing plate, and a nut screwed with the bolt.
The anticorrosion layer is arranged between the fixing plate and the flat portion, and after the bolt is passed through the anticorrosion layer and the flat portion, the nut is screwed onto the surface of the steel pipe sheet pile. The anticorrosion structure according to (1) above, which is fixed.
(3) The anticorrosion structure according to (1) or (2) above, further comprising a cushion layer between the anticorrosion metal and the anticorrosion layer.
(4) The anticorrosion structure according to (3) above, further having a water-impervious sheet between the anticorrosion layer and the cushion layer.

According to the present invention, the anticorrosion structure can be brought into close contact with the steel pipe sheet pile even if the degree of skill of the builder is low at the time of casting and even if the wall thickness is reduced due to corrosion after casting. Further, since there is no flange portion, it is possible to provide an anticorrosion structure that is not easily damaged by an external force such as collision of drifting objects such as driftwood and drift ice and waves.

It is schematic cross-sectional view which shows the state which attached the anticorrosion structure of this invention to the sea side of the steel pipe sheet pile installed in the revetment G. It is the schematic sectional drawing of the bellows structure part. It is a schematic cross-sectional view which shows the state which the conventional anticorrosion structure is attached to the sea side of the steel pipe sheet pile installed in the revetment G.

The anticorrosion structure of the present invention will be described.
The anticorrosion structure of the present invention is formed on the surface of a steel pipe sheet pile that is a part of an existing structure. Further, the anticorrosion structure of the present invention includes at least an anticorrosion layer, a corrosion resistant metal plate, and fixing means for fixing these to the steel pipe sheet pile.

In the anticorrosion structure of the present invention, the existing structure is, for example, an offshore structure, a river structure, a harbor structure, or the like, and is an existing structure having a portion mainly in contact with water (seawater or the like). Such an existing structure may have a steel pipe sheet pile in a portion of contact with water such as seawater, for example, a splash zone or a tidal zone.
The anticorrosion structure of the present invention is used for anticorrosion of such a steel pipe sheet pile.

The anticorrosion structure of the present invention will be described with reference to a diagram showing a specific embodiment.
FIG. 1 is a diagram showing a state in which a steel pipe sheet pile 1, which is an offshore structure, is installed on a revetment G, and the anticorrosion structure 2 of the present invention is attached to the sea S side (outside) of the steel pipe sheet pile 1. , FIG. 2 is an enlarged view (schematic view) of the bellows structure portion 361 in FIG.

In FIG. 1, the same parts as those in the conventional mode described with reference to FIG. 3 (hereinafter, also referred to as “the above-mentioned conventional mode”) are designated by the same reference numerals.
Hereinafter, a portion different from the above-mentioned conventional embodiment will be described in detail, and the description of the same portion will be simplified.
As in the case of the conventional aspect described above, in the anticorrosion structure of the present invention, the side where water such as seawater exists with respect to the existing structure is also referred to as "outside", and the opposite side is also referred to as "inside". Therefore, the sea S side is "outside" with respect to the revetment G, and the opposite side is "inside".

In FIG. 1, the steel pipe sheet pile 1 is a connecting portion arranged so as to be sandwiched between a main body portion 11 having a semicircular cross section formed of a long tubular steel material and two main body portions 11 as in the above-described conventional embodiment. A wall-shaped structure (existing structure) is formed by connecting the main body portion 11 with the connecting portion 12. Although the cross section of the steel pipe sheet pile 1 is substantially circular in FIG. 1, about half (semi-circular portion) of this is used as the main body portion of the steel pipe sheet pile 1.
Further, the connecting portion 12 is also the same as the above-mentioned conventional embodiment, and the female connecting portion 122 made of angle steel having an L-shaped cross section and the male connecting portion 121 made of T-shaped steel having a T-shaped cross section are connected. .. In addition to the LT type shown in FIG. 1, the connecting portion may be a PP type, a PT type, or the like.

The anticorrosion structure 2 of the present invention shown in FIG. 1 includes an anticorrosion layer 25 formed on the surface of a steel pipe sheet pile 1, a cushion layer 27 on the outside thereof, and a corrosion resistant metal plate 3 on the outside thereof. Then, the anticorrosion layer 25, the cushion layer 27, and the corrosion-resistant metal plate 3 are fixed by the fixing means 4 so as to be in close contact with the surface of the steel pipe sheet pile 1.

<Corrosion resistant metal plate>
The corrosion-resistant metal plate 3 included in the anticorrosion structure 1 of the present invention will be described.
The corrosion-resistant metal plate 3 has a main body portion 36 having a semicircular cross section along the main body portion 11 of the steel pipe sheet pile 1, and flat portions 37 for tightening and fixing formed at both ends (edges) thereof.
The bellows structure portion 361 is provided at least in a part of the main body portion 36.

The bellows structure portion 361 will be described with reference to FIG. FIG. 2 is an enlarged cross-sectional view (schematic view) of the bellows structure portion 361.
The bellows structure portion of the anticorrosion structure 2 of the present invention has a mode in which peaks and valleys are repeated as its cross section is shown in FIG. The distance between the peak and the valley, that is, the length indicated by H in FIG. 2, is preferably 1 to 5 mm, more preferably 2 to 3 mm.
The bellows shrinks by applying a force in the direction of the arrow shown in FIG. When placing the corrosion-resistant metal plate 3, it is preferable to shrink the bellows once, pull it in the opposite direction, and fix it to the surface side of the steel pipe sheet pile 1 by the fixing means 4 while maintaining the state. By doing so, the corrosion-resistant metal plate 3 is subjected to a force in the direction toward the surface of the steel pipe sheet pile 1, so that the anticorrosion structure 2 of the present invention can be brought into close contact with the surface of the steel pipe sheet pile 1. In this case, the anticorrosion structure can be brought into close contact with the steel pipe sheet pile even if the builder's skill level is insufficient at the time of casting. Further, even if the steel pipe sheet pile is thinned with the passage of time after the placement or the dimensional error due to the expansion and contraction of the joint portion generated at the time of driving, the anticorrosion structure can be brought into close contact with the steel pipe sheet pile.

The material of the corrosion-resistant metal plate is not particularly limited. For example, examples of the corrosion resistant metal include titanium, titanium alloy, and stainless steel (for example, SUS316, SUS316L, SUS317, and SUS317 with Cu, N, etc. added to improve pitting corrosion resistance, etc.), and the metal is titanium or a titanium alloy. Is preferable.
The thickness of the corrosion-resistant metal plate is also not particularly limited, but is preferably 0.3 to 5.0 mm, more preferably 1.0 to 3.0 mm. This is because it is lightweight and easy to handle during construction.
Further, the corrosion resistant metal plate may be formed by joining two or more plates.

<Anti-corrosion layer>
The anticorrosion layer 25 is provided so as to be in close contact with the outer surface of the steel pipe sheet pile 1.
The anticorrosive layer can be formed by using a conventionally known anticorrosive agent. For example, a commercially available anticorrosive agent such as petrolatum (petrolatum paste, petrolatum sheet), epoxy resin, oxidative polymerization resin, or the like can be used to form an anticorrosive layer. For example, a petrolatum sheet can be attached to the inside of a corrosion-resistant metal or the surface of a steel pipe sheet pile, and the petrolatum paste can be applied to the outside or the surface of the sheet pile to form an anticorrosion layer.
The amount of the anticorrosion layer provided so as to be in close contact with the outer surface of the steel pipe sheet pile is preferably 2.0 to 4.0 kg / m ² as the mass of the anticorrosion layer per unit area of the steel pipe sheet pile, preferably 2.0. more preferably ~3.0kg / m ^2, more preferably from 2.0~2.5kg / m ^2, further preferably 2.0~2.2kg / m ^2.
The thickness of the anticorrosion layer is not particularly limited, but is preferably 2 to 5 mm, more preferably 2 to 4 mm, and even more preferably 2 to 3 mm.

<Cushion layer>
The anticorrosion structure of the present invention may include a cushion layer 27 made of a cushioning material between the anticorrosion layer 25 and the corrosion resistant metal plate 3.
Examples of the cushioning material include foamed polyethylene.
The thickness of the cushion layer 27 is not particularly limited, but is preferably 5 to 20 mm, more preferably 10 to 15 mm.

<Water shield sheet>
The anticorrosion structure of the present invention may further have an impermeable sheet between the anticorrosion layer 25 and the cushion layer 27.
As the impermeable sheet, for example, a conventionally known sheet made of polyethylene can be used.

<Fixing means>
The fixing means 4 includes a fixing plate 41, a bolt 44, a washer 45, and a nut 47. The fixing plate 41 is welded and fixed to the surface of the connecting portion 12 (female connecting portion 122). Further, the bolt 44 is fixed to the fixing plate 41 and projects toward the sea S side. Then, the bolt 44 is inserted into the insertion hole provided at the end of the corrosion-proof layer 25, the cushion layer 27, and the corrosion-resistant metal plate 3, and the bolt 44 is inserted into the insertion hole of the washer 45 from the sea S side, and then the nut 47 is inserted. Screw and fix.
It is preferable to properly insulate the bolt 44 and the corrosion-resistant metal plate 3 so that they do not come into electrical contact with each other.

The anticorrosion structure of the present invention as shown in FIG. 1 can adhere the anticorrosion structure to the steel pipe sheet pile even if the degree of skill of the builder is low at the time of casting. In addition, the anticorrosion structure can be brought into close contact with the steel pipe sheet pile even if there is a dimensional error due to expansion and contraction of the joint portion that occurs during casting and the steel pipe sheet pile is thinned with the passage of time after the placement. Furthermore, since there is no flange, it is not easily damaged by external forces such as collision of drifting objects such as driftwood and drift ice and waves.

1 Steel pipe sheet pile 11 Main body 12 Connecting part 2 Corrosion-proof structure of the present invention 25 Corrosion-proof layer 27 Cushion layer 3 Corrosion-resistant metal plate 31 Flange part 33 Bolt 35 Nut 36 Main body part 37 Flat part 4 Fixing means 41 Fixing plate 44 Bolt 45 Washer 47 Nut G Seawall S Sea 121,122 Joint 361 Bellows structure

Claims (4)

An anticorrosion structure including at least an anticorrosion layer and a corrosion-resistant metal plate formed on the surface of a steel pipe sheet pile that is a part of an existing structure, and a fixing means for fixing these to the steel pipe sheet pile.
The corrosion-resistant metal plate includes a main body portion having a bellows structure portion at least partially covering the main body portion having a semicircular cross section of the steel pipe sheet pile, and a flat portion formed on the edge of the main body portion.
An anticorrosion structure configured to be in close contact with the surface of the steel pipe sheet pile by contracting the bellows structure portion at the time of driving and after driving. The fixing means includes a fixing plate fixed to the steel pipe sheet pile, a bolt fixed to the fixing plate, and a nut screwed with the bolt.
The anticorrosion layer is arranged between the fixing plate and the flat portion, and after the bolt is passed through the anticorrosion layer and the flat portion, the nut is screwed onto the surface of the steel pipe sheet pile. The anticorrosion structure according to claim 1, which is fixed. The anticorrosion structure according to claim 1 or 2, further comprising a cushion layer between the anticorrosion metal plate and the anticorrosion layer. The anticorrosion structure according to claim 3, further comprising a water-impervious sheet between the anticorrosion layer and the cushion layer.

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