JP4014299B2 - Anti-corrosion zone on the wall of marine steel structures - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
For example, the foundation of an offshore structure is formed on a vertical wall surface by connecting steel piles such as steel sheet piles and steel pipe sheet piles to each other and driving them into the seabed. The present invention relates to an anticorrosion belt formed on the tidal droplet splash on the wall surface.
[0002]
[Prior art]
The tidal splash zone of steel piles in offshore structures is highly corroded by seawater. In order to prevent and reduce this corrosion, the steel pile is covered with concrete, for example. Conventionally, the following a. And b. The concrete coating of was known. That is, a) A method in which concrete is placed between a steel pile and a mold using a mold, and then the mold is removed. B) A method in which concrete is placed between a steel pile and a formwork using a formwork made of FRP or the like, and thereafter, the formwork made of FRP or the like is used as a padding without being removed.
[0003]
However, a) has a problem in that since concrete is in direct contact with seawater, there is an outflow of cement due to seawater, and seawater directly flows into the cracks in the concrete and corrodes the steel pile. In addition, since the FRP form of (b) becomes brittle by ultraviolet rays, there is a problem that the form is destroyed by collision of floating substances, etc. when used for a long time.
[0004]
Although it is not the anticorrosion zone of the wall surface which connected the steel pipe pile, in Japanese Utility Model Publication No. 56-9702 and Unexamined-Japanese-Patent No. 7-166568, the anticorrosion zone applied to a single steel pipe is described. FIG. 4 is an example. That is, the anticorrosive material impregnated tape 21 or the like is wound around the outer periphery of the single steel pipe 20, the anticorrosive metal cover 22 is applied to the outer periphery of the anticorrosive material impregnated tape 21, and the anticorrosive metal cover 22 is used while being buried. At this time, if the corrosion-resistant metal cover 22 is densely arranged and disposed on the outer surface of the corrosion-resistant material-impregnated tape 21, a preferable corrosion-resistant zone of the steel pipe is obtained.
[0005]
In this single steel pipe anticorrosion zone, the anticorrosive metal cover 22 is disposed on the outer surface of the anticorrosive material impregnated tape 21 by fastening the anticorrosive metal plate around the outer periphery of the anticorrosive material impregnated tape 21 and fastening both ends. I can do it. However, when the surface to which the anticorrosion belt is applied is a wall surface, the wall surface is formed by a number of steel piles connected to each other by claw portions as will be described in detail later. That is, in this case, since the claws are connected to each other, the corrosion-resistant metal plate cannot make the outer periphery of each steel pile as shown in FIG.
[0006]
[Problems to be solved by the invention]
Titanium has excellent corrosion resistance in the tidal splash zone. Moreover, it does not become brittle by ultraviolet rays. Therefore, if titanium can be disposed on the outer surface of concrete as a formwork, the concrete can be protected over a long period of time, and as a result, the steel pile inside can be protected from corrosion. However, because titanium is expensive, a thick titanium formwork is not economical.
An object of the present invention is to provide an anticorrosion zone on the wall surface of an offshore structure, in which a titanium thin plate is embedded as a formwork and arranged in close contact with the outer surface of the concrete.
[0007]
[Means for Solving the Problems]
1A and 1B are explanatory views of the anticorrosion belt of the present invention. FIG. 1A is a cross-sectional explanatory view, FIG. 1B is a perspective explanatory view of the structure, and FIG. The present invention is an anticorrosion zone formed in a tidal droplet zone on a vertical wall surface of an offshore structure in which steel piles are interconnected. The steel piles 1-1 and 1-2 are connected by combining male claws 2 and female claws 3, and each lower end is driven into the seabed to form a vertical wall surface. Steel piles are easily corroded in the tidal zone. The present invention is an anticorrosion zone for preventing and reducing the corrosion of the tidal droplet splash zone.
[0008]
The anticorrosion belt of the present invention is formed by an underwater inseparable concrete layer 4 having a predetermined thickness arranged on the vertical wall surface, and a protective plate 5 made of a titanium thin plate covering the outer surface of the underwater inseparable concrete layer 4. ing. Moreover, the protective plate 5 made of a thin titanium plate alternately includes an outer peripheral plate 6 arranged facing a portion other than the connecting portion of the steel pile and a connecting plate 7 arranged facing the connecting portion of the steel pile. Connected and formed.
[0009]
The outer peripheral plate 6 has a plate shape in which folded portions 8 having a width of 5 to 50 mm opposite to the steel side are formed on the left and right ends. Further, the connecting plate 7 has a groove shape having flanges 10 and 10 'having an internal angle θ with the web 9 of 90 ° or more on the left and right of the web 9, and steel pipe piles 1-1 and 1 at the side ends of both flanges 10 and 10'. Folds 11 and 11 ′ having a width of 5 to 50 mm opposite to the 1-2 side are formed, and the web 9 is made of a thin titanium plate in which a plurality of bolt fittings 12 are formed.
[0010]
The protective plate 5 made of a thin titanium plate is formed by connecting the outer peripheral plate 6 and the connecting plate 7, and this connection is made by matching the outer peripheral plate folding 8 and the connecting plate folding 11, with a separately created cross section. By using the C-shaped titanium sheath tube 13, the folded portion 8 of the outer peripheral plate 6 and the folded portion 11 of the connecting plate 7 are fitted together inside the C-shaped sheath tube 13. Connecting.
[0011]
Note that the entire protective plate 5 has one end joined to a steel pile, for example, a claw 3 of 1-2, and the other end of a bolt 14 protruding from the underwater non-separable concrete layer 4 to the bolt insertion hole of the joining plate 7. And the nut 15 is tightened and held in the steel pile.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
The anticorrosion belt of the present invention is a wall surface of a tidal splash zone of a marine structure formed by a number of steel piles 1 (1-1, 1-2,...) Interconnected by male claws 2 and female claws 3. In addition, a protective plate 5 made of a thin titanium plate in which the outer peripheral plate 6 and the connecting plate 7 are connected by a sheath tube 13 is fixed by bolts 14 and nuts 15 at an interval corresponding to the thickness of the underwater inseparable concrete. Then, underwater non-separable concrete is placed between the protective plate 5 and the steel pile 1 (1-1, 1-2,...). After placing the underwater non-separable concrete, if necessary, the nut 15 is tightened so that the titanium protective plate 5 is further adhered to the concrete. Thereafter, the titanium thin protective plate 5 is buried and formed into a formwork. .
[0013]
Although the protective plate 5 made of a titanium thin plate of the present invention is a thin plate having a thickness of 1 mm or less, the protective plate 5 has excellent corrosion resistance in a titanium tidal droplet zone, and therefore does not wear out over a long period of time. Further, since the protective plate 5 made of a titanium thin plate is disposed in close contact with the concrete, the concrete is protected for a long period of time, and the steel pile inside is protected from corrosion.
[0014]
Since the steel piles are connected to each other by the claws 2 and 3, the corrosion of the wall surface of the offshore structure can interfere with the claws, causing the titanium thin plate to make a round along the outer surface of each steel pile. However, according to the present invention, a concrete layer having a desired uniform thickness can be formed on the outer surface of a steel pile, and a protective plate made of a thin titanium plate can be disposed on the outer surface of the concrete layer.
[0015]
In the present invention, the outer peripheral plate 6 and the connecting plate 7 are connected using the sheath tube 13, but this connection is simple at the site construction. Therefore, the anticorrosion belt of the present invention can be easily formed on the wall surface of the offshore structure. In the case where the bolts 14 and the nuts 15 are made of steel, for example, by covering a portion protruding from the connecting plate 7 with a cap filled with a known quick-drying cement or organic polymer compound, the corrosion is prevented.
[0016]
In the present invention, in order to prevent corrosion of the steel pile 1 (1-1, 1-2,...), A large gap is not generated between the underwater inseparable concrete layer 4 and the titanium protective plate 5. Therefore, it is preferable to keep them in close contact. 2A and 2B are explanatory views of the anticorrosion belt of the present invention in which the adhesion is further excellent, in which FIG. 2A is a perspective view illustrating the structure, FIG. 2B is a schematic cross-sectional view, and FIGS. 2) FIG. 2 is a cross-sectional view taken along the line II in FIG. That is, in FIG. 2, the outer peripheral plate 6 is characterized in that a titanium anchor fitting 16 having a protruding length equal to the thickness of the concrete layer 4 is joined to the surface of the steel pipe pile 1 side. It is a protection zone.
[0017]
As shown in FIG. 2B, the titanium anchor fitting 16 is joined to the outer peripheral plate 6 in advance by welding 18, for example. When the anchor metal fitting 16 is used, the flange 19 of the anchor metal fitting 16 is fixed to the concrete. For this reason, the anchor metal fitting 16 holds the outer peripheral plate so that the outer peripheral plate 6 is not separated from the concrete. 2 has the same protruding length as the thickness of the concrete layer 4, so that the distance between the steel pile 1 (1-1, 1-2,. It also has a function as a spacer for making the thickness of the layer 4 uniform.
[0018]
The anchor fitting 16 is preferably provided with apertures 17-1, 17-2, 17-3 as shown in FIG. 2C-1. Alternatively, as shown in FIG. 2C-2, it is preferable to dispose intermittently, such as 16-1, 16-2, 16-3, without being arranged over the entire length. When placing concrete, the concrete flows in the P direction or the Q direction in FIG. At this time, if the apertures 17-1, 17-2, 17-3 are arranged in the anchor bracket 16, or the anchor bracket 16 is intermittently arranged like 16-1, 16-2, 16-3. In this case, the flow of the concrete is not hindered when the concrete is placed, and it flows freely in the P direction or the Q direction through the opening or the missing portion and is uniformly filled.
[0019]
FIG. 3 is an explanatory view of another example of the present invention in which the underwater inseparable concrete layer 4 and the titanium protective plate 5 are brought into close contact with each other. That is, the outer peripheral plate 6 is an anticorrosion belt in which a titanium anchor fitting 16 ′ having a protruding length shorter than the thickness of the concrete layer 4 is joined to the surface facing the steel pile. At this time, the anchor fitting 16 'is also joined to the outer peripheral plate 6 in advance by welding or the like, as in the case of FIG. In this anchor metal fitting 16 ', the flange 19' of the anchor metal fitting 16 'is embedded and fixed in the concrete 4, and therefore the anchor metal fitting 16' is provided with the outer peripheral plate 6 so that the outer peripheral plate 6 is not separated from the concrete layer 4. Holding.
[0020]
【The invention's effect】
The anticorrosion belt of the present invention protects concrete for a long period of time, and can protect the steel pile inside the concrete from corrosion. Titanium is used in the present invention, but since it is a thin plate, the amount used is small and the cost is not increased. The anticorrosion belt of the present invention is easy to construct on site, and therefore can be formed on a wide wall surface of an offshore structure.
[Brief description of the drawings]
BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory diagram of an anticorrosion belt of the present invention.
FIG. 2 is an explanatory diagram of an example of the anticorrosion belt of the present invention in which the adhesion between the concrete layer and the titanium protective plate is excellent.
FIG. 3 is an explanatory view of another example of the anticorrosion belt of the present invention in which the adhesion between the concrete layer and the titanium protective plate is excellent.
FIG. 4 is an explanatory view of an example of a conventional anticorrosion belt applied to a single steel pipe.
[Explanation of symbols]
1 (1-1, 1-2): steel pile, 2: male nail, 3: female nail, 4: underwater non-separable concrete layer, 5: protective plate made of titanium thin plate, 6: outer peripheral plate, 7: Connecting plate, 8: Folding of outer peripheral plate, 9: Web of connecting plate, 10: Flange of connecting plate, 11: Folding of connecting plate, 12: Bolt fitting hole, 13: Saya tube, 14: Bolt, 15: Nut , 16 (16-1, 16-2, 16-3): Titanium anchor fitting, 16 ': Titanium anchor fitting, 17 (17-1, 17-2, 17-3): Opening part, 18: welding, 19: flange of titanium anchor fitting, 19 ': flange of titanium anchor fitting, 20: single steel pipe, 21: anticorrosive impregnated tape, 22: corrosion resistant metal cover.

Claims (3)

An anticorrosion zone formed in a vertical wall tidal splash zone where steel piles are connected to each other, the anticorrosion zone comprising an underwater non-separable concrete layer formed on the vertical wall surface and the underwater non-separable concrete layer. It consists of a protective plate made of titanium thin plate that covers the outer surface of the separable concrete layer, and the protective plate made of titanium thin plate faces the outer peripheral plate and the connecting portion that are arranged facing the portion other than the connecting portion of the steel pile. It is formed by connecting the connected plates alternately, and each outer peripheral plate is a plate shape in which the left and right ends are formed with a 5 to 50 mm wide turn in the opposite direction to the steel pile side, each connecting plate is It has a groove shape with flanges with an inner angle of 90 ° or more on the left and right sides of the web, the side ends of both flanges are formed with a 5-50 mm width fold in the direction opposite to the steel pipe pile side, and a plurality of bolts It is made of a thin plate with a fitting hole, and the connection between the outer peripheral plate and the connecting plate is The folds of the outer plate and the connecting plate are fitted together inside the C-shaped section by using a T-sheet made of a thin titanium plate with a C-shaped cross section. The entire protective plate is connected to the claws of the steel pile, and the other end is inserted into the other end of the bolt protruding from the underwater non-separable concrete layer. An anticorrosion zone on the wall of a marine steel structure, characterized by being held by steel piles. The marine steel structure according to claim 1, wherein the outer peripheral plate is joined to a steel pile side surface with a titanium anchor fitting having a projection length equal to the thickness of the concrete layer. Anti-corrosion belt on the wall. The outer peripheral plate is characterized in that a titanium anchor fitting having a protruding length shorter than the thickness of the concrete layer is joined to the surface facing the steel pile, Anti-corrosion zone on the wall of marine steel structures.

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