JPH0154487B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a corrosion protection method for steel pipe piles for supporting marine facilities, etc., and it is an object of the present invention to provide a method by which a coating with excellent corrosion resistance can be applied on-site to the outer surface of a steel pipe pile efficiently and at low cost. be. Marine facilities such as bridges, sea berths, and port facilities are generally supported by steel pipe piles driven into the seabed. The tidal zone (hereinafter referred to as the tidal zone) and the area that is exposed to wave spray (hereinafter referred to as the splash zone) are susceptible to corrosion due to the influence of seawater, and for this reason, a countermeasure is taken to apply an anti-corrosion coating to this area.
Conventionally, methods for providing such anti-corrosion coatings include pouring concrete on site around the piles, pouring mortar using synthetic resin formwork containing reinforcing material (FRP formwork), and placing concrete around the piles on-site. The method of painting the surrounding area with paint is mainly used. Among these methods, method (2) involves placing a formwork around the pile, pouring concrete into it, and removing the formwork after the concrete has hardened, but the concrete covering obtained by this method is similar to the material itself. Not only does it have a problem with anti-corrosion performance, but it also has the drawback of being prone to cracking, which requires a fairly large thickness, and also has the disadvantage that poor construction can have a large effect on anti-corrosion performance. In addition, in the method described above, a synthetic resin formwork containing reinforcing material is attached to the outer periphery of the steel pipe pile, mortar is poured into this, and the formwork itself and the mortar inside the formwork form an anti-corrosion coating. It is designed to simplify and standardize the on-site placement of mortar, and to reduce the mortar thickness due to the corrosion resistance and water resistance of the formwork. However, since the formwork that forms part of the anti-corrosion coating is made of synthetic resin, it cannot be said to have sufficient impact resistance, and the formwork itself is not cheap, resulting in high costs. be. Furthermore, in the method described above, paint is generally applied to the pile surface using a brush, roller, spray, etc., but with this method, it is difficult to form a coating film with a thickness of 1 mm or more even after applying several coats. The disadvantage is that it is easily susceptible to damage that reaches the pile surface. In addition, it is necessary to apply anti-corrosion coating to parts submerged in water, but it is not easy to apply the coating underwater with the above method, and even if it is possible to apply it underwater using an underwater curing type paint, it is difficult to apply it underwater. The paint is easily washed away by water due to the effects of waves, etc., making it difficult to ensure proper coverage. The present invention was devised in view of the drawbacks of the conventional methods as described above, and its basic features are as follows. That is, a release film is provided in advance on the inner surface of a split formwork, and a predetermined gap is created between the formwork and the outer circumferential surface of the steel pipe pile using spacers to form the steel pipe to be anti-corrosion treated. Attach to the outer surface of the pile. In this case, the lower part of the formwork and the outer peripheral surface of the steel pipe pile are such that the upper sealing material is thick and the lower sealing material is thin, and the annular step between both sealing materials is supported by the formwork constituent members. The seal should be sealed with a compression type elastic sealing member such as After installing such a formwork, a specific gravity of 1.5~1.5 is added to the void from the bottom of the formwork.
The formwork is removed from the steel pipe pile by injecting and filling a liquid curable anticorrosive paint of 2.0. By doing so, it is possible to efficiently and efficiently apply a strong anti-corrosion coating to the outer peripheral surface of the steel pipe pile. The outline of the basic structure of the present invention will be explained below based on FIGS. a indicates the water surface. To carry out the present invention, first, if the structure is an existing structure, scrape off shells, rust, etc. adhering to the surface of the pile, finish it with a power tool such as a jet chisel or sander, and then cover the pile. A split mold frame 2 with a release film provided on the inner surface around the outer periphery of the part to be applied.
Attach 2. The formwork 2, 2 is made of light metal such as steel, aluminum, plastic or FRP, etc., and is divided into two or three parts, each of which is attached to the outer periphery of the pile using bolts, etc. They are connected to form an integral cylindrical body. At this time, the formworks 2, 2 are mounted so as to have a gap S of a predetermined width between them and the outer peripheral surface of the steel pipe pile 1 using spacers (not shown). This is to maintain the width of the gap constant even if the steel pipe pile 1 is flat or bent due to poor roundness, and to make the thickness of the coating film uniform. be. The coating thickness targeted by the method of the present invention is approximately 10 mm, but steel pipe piles generally have an outer diameter of 1000 mm or more (outer diameter tolerance: ±10 mm); 3000～
Since it is necessary to cover a length of about 5000 mm with anti-corrosion coating,
Even if the shape of the steel pipe pile is defective within the tolerance, the void S
This is because the width of the field is extremely affected. In addition, when the formworks 2, 2 are installed, the lower part thereof and the outer circumferential surface of the steel pipe pile 1 are connected to the compression type elastic seal member 3.
It is in a sealed state. Note that this seal portion has a specific configuration as described later.
This elastic sealing member 3 is provided in advance on the outer peripheral surface of the steel pipe pile 1 or on the formworks 2, 2 themselves, and is compressed when the formworks 2, 2 are attached to form a reliable seal for preventing paint leakage. The forms 2, 2 mounted on the steel pipe pile 1 in this manner are held in the longitudinal direction of the pile by the spacer and seal member 3. In this state, the void S is filled with a curable anticorrosive paint. That is, an injection port 4 for the anticorrosion paint is provided at the bottom of the formwork 2, and the anticorrosion paint 8 is poured into the injection port 4.
injected from. This can be solved by injecting anti-corrosion paint from the top or middle of the formworks 2, 2 using this construction method.
This is because air gets mixed in and forms air bubbles in the coating film, and for this reason, the anticorrosive coating 8 is injected by pushing it up from the bottom. As the above-mentioned anticorrosive paint, one having a specific gravity of about 1.5 to 2.0 is used. Since the formwork is usually installed with its lower part submerged in water, water will remain in the formworks 2, 2. Therefore, in the present invention, an anti-corrosive paint with a large specific gravity is used, and by injecting this anti-corrosive paint 8, the water in the formworks 2, 2 is pushed up and overflowed from the upper ends of the formworks 2, 2. The coating layer can be formed by completely eliminating the water in 2. The anticorrosive paint is preferably a paint that hardens at room temperature, such as liquid bisphenol A type epoxy resin, bisphenol F type epoxy resin with a molecular weight of 350 to 420, as shown in Japanese Patent Application No. 56-17523,
An epoxy resin made of one or more aliphatic epoxy resins, a filler made of one or more of talc, barite, and calcium carbonate, to which a coloring pigment is added if necessary, and the epoxy resin cured. A water-curing curing agent is mixed with the water-curable curing agent to give a total specific gravity of 1.3 or more, and an anti-diluent consisting of an aliphatic diglycidyl ether and/or an aromatic diglycidyl ether is further mixed therewith to give a total specific gravity of 1.3 or more. Those with a specific gravity of 1.3 or higher are used. In FIG. 1B, 5 is a paint hose connected to the injection port 4, 6 is a paint container, and 7 is a pump.
The anticorrosive paint 8 is pumped from the paint container 6 into the air gap S by the pump 7.
The filling operation is completed when the liquid level of the anticorrosive paint 8 reaches the upper end of the molds 2, 2. Next, after the anticorrosive coating 8 has hardened, the molds 2, 2 are removed, thereby forming a coating film 8' having a thickness corresponding to the width of the gap S, as shown in FIG. 1C. . The coating film 8' made of the anticorrosive paint 8 thus obtained can be configured to have an arbitrary thickness by adjusting the width of the gap S. Figures 2 to 7 show examples of the method of the present invention, in which the formworks 2 and 2 used are divided into two parts, and are made of thin steel plates or synthetic resins such as FRP, vinyl chloride, and polyethylene. configured. The formworks 2, 2 need to have appropriate strength to withstand reuse. For example, in the case of FRP formwork, it has a thickness of about 5 mm and reinforcing ribs 9
A type with a circumferential direction is used. Further, the formworks 2, 2 have flanges 10, 10 at their respective joints, and can be fastened together with bolts and nuts via the flanges 10, 10. Further, an elastic sealing member 3 is wrapped in advance around the peripheral surface of the pile where the lower portions of the forms 2, 2 are located. The elastic sealing member 3 has a two-stage sealing structure consisting of an upper member 31 and a lower member 32, both of which are made of compressible soft foam rubber, soft plastic, or the like. However, the upper member 31 is constructed with a thick wall (for example, 15 to 30 mm when the width of the gap is 10 mm), so that it can sufficiently conform to the unevenness of the pile surface caused by corrosion etc. when subjected to compression. In contrast, member 32 is thin (3 to 5 mm)
This two-stage seal structure ensures reliable sealing. However,
The above-described split formworks 2, 2 are attached to the outer periphery of the pile with their lower portions located at the position of the elastic seal member 3, as shown in FIG. 2, and between the opposing flanges 10, 10. Elastic seal members 11, 11 made of rubber or plastic are interposed, and the bolt 1
2 and a nut 13. Further, in this state, the elastic seal member 3 is compressed by the molds 2, 2, and a reliable seal is formed. In other words, the viscosity of paints such as epoxy resins that must be injected into the voids of the formwork is low, so they tend to leak from the seals, and in addition, the length of the anticorrosion-treated part of steel pipe piles is usually about 3000 to 5000 mm. The load of the paint filled into the gap of this length is applied to the lower seal part, and the paint needs to be press-fitted into the gap under high pressure, so the seal at the bottom of the formwork cannot be reliably sealed. needs to be done. In this regard, in the present invention, a reliable seal can be obtained by the upper and lower two-stage seal structure consisting of the thick member 31 and the thin member 32. That is, in this seal structure, the elastic seal member 3, especially the upper thick member 31, is subjected to large compression to form a strong seal, and as shown in FIG. The portion 23 (annular) supports the member 31 via the annular stepped portion 30 between the members 31 and 32. As a result, the member 31 is supported by the protrusion 23 against the load of the paint, and not only can its sealing function be maintained, but also the load of the injected paint and the pressure at the time of injection can cause the member 31 to
is compressed in the vertical direction, the surface pressure between the member 31 and the outer surface of the pile and the inner surface of the formwork increases, thereby ensuring a very high degree of sealing performance. Note that the upper parts of the molds 2, 2 are not sealed, so that air or water can be removed when injecting the anticorrosion paint. In addition, with the formworks 2, 2 installed in this manner, a gap S is formed between the inner peripheral surfaces of the formworks 2, 2 and the outer peripheral surface of the steel pipe pile 1. Spacers 14 are used to maintain constant direction and length. That is, female screw holes 15 are provided at appropriate intervals in the circumferential direction and also in the longitudinal direction of the formworks 2, 2.
and fixing nuts 16 are provided, and bolts 17 are attached to these.
Screw in and insert the tip into the formwork 2, 2 for the desired gap.
These are made to protrude inward and come into contact with the pile surface, and these constitute the spacer 14. Note that a nut 18 is attached to the bolt 17 to ensure a seal between the fixing nut 16 and the bolt 17. Maintaining the clearance by this spacer 14 can, for example, hold a steel pipe pile with an outer diameter of 600 mm
When covering a pile with formworks 2, 2 over a length of mm, it is sufficient to cover the piles at about 4 locations in the circumferential direction at the center of formworks 2, 2, but for piles with an outer diameter of 1000mm or more, more In addition, the longer the formwork is, the more clearance must be maintained at multiple locations in the longitudinal direction. Note that this spacer 14 does not necessarily have to be made of the bolt 17, etc., but if it is made of a bolt, the bolt tip 172 is made of hard synthetic resin or the like as shown in FIG. The bolt body 1 is made into a bayonet structure.
71, and only the bolt body 171 may be removed after the work is completed. Alternatively, spacers made of the same material or similar to the anticorrosive paint may be adhered in advance to some places on the surface of the pile, and then the formwork may be attached to form the voids. Furthermore, a release film 19 is provided in advance on the inner peripheral surfaces of the molds 2, 2, as shown in FIG. Generally, the anticorrosive paint used in this method has an adhesive strength of 50 kg/cm2 or ^more , and the formwork area is large (2
3 ^m2 or more), therefore, if the anticorrosive paint is injected directly inside the formworks 2, 2, it will be extremely difficult to remove the formworks 2, 2 after the paint has hardened. Therefore, in the present invention,
A release film 19 is provided in advance on the inner surface of the mold,
This mold release film 19 is adhered to the coating film, and the mold is released by peeling the mold frame from this mold release film 19. As the release film 19, for example, a synthetic resin film such as polyethylene or polyester is used. In such a case, the film needs to have enough rigidity to prevent wrinkles, and for this reason, a film having a certain thickness (for example, 0.2~ for polyester
0.3mm) is used. Such a release film 19 is, for example, a double-sided adhesive tape 2 attached at appropriate intervals in the inner circumferential direction of the molds 2, 2.
It is pasted in advance to the inner circumferential surfaces of the formworks 2, 2 via 0 or the like. Then, with the formworks 2, 2 installed as described above, the air gap S is opened from the injection port 4 at the bottom of the formworks 2, 2.
The anticorrosion paint 8 is injected into the mold, and the liquid level reaches the formwork 2,
Stop the injection when it reaches the top of 2. Then, the anticorrosion paint 8 is cured, and after curing, the formworks 2, 2
is removed, and an anti-corrosion coating is formed on the outer surface of the steel pipe pile 1. During this mold release, since the mold release film 19 is firmly attached to the coating film 8', the molds 2, 2 can be easily removed by simply peeling them off from the mold release film 19. In order to make this mold release easier, bolt holes 21 are provided only in one of the opposing flanges 10 as shown in FIG. Press both formworks 2,
It is possible to apply a force that separates the two. Note that by using the release film 19 as described above, the surface of the resulting coating film can be made extremely smooth. Further, when the spacer 14 is as shown in FIG. 8, the bolt body 171 is rotated when removing the formworks 2,
72, so that the bolt tip 172 remains embedded in the coating. In addition, if the spacer 14 is as shown in FIG.
However, in this case, a hole will remain in the coating film 8' after the bolt 17 is pulled out, and this hole will be filled with putty after the formwork 2, 2 is removed. Filled with paint. The table below shows the results of a 5-year exposure test of anti-corrosion coatings applied on-site using the method of the present invention in comparison with those using conventional methods. In the method of the present invention, a paint as shown in the above-mentioned Japanese Patent Application No. 17523/1984 was used as an anticorrosive paint.

【table】

[Table] As is clear from the above table, the method of the present invention makes it possible to obtain a tough and durable anti-corrosion coating. According to the present invention described above, it is possible to efficiently coat the outer surface of a steel pipe pile for supporting marine structures and the like with excellent corrosion resistance at a relatively low cost.
In particular, in the present invention, the coating film is formed by using a split mold, and a relatively thick coating film can be efficiently formed in one step. Since a release film is used for the formwork, the formwork can be easily removed after construction, resulting in good workability. A strong seal is formed at the bottom of the formwork, which prevents paint from flowing out and provides a good quality paint film. A paint with a specified specific gravity is used, and it is injected into the void from the bottom of the formwork.
This prevents air from getting into the paint film and water from entering the film, resulting in a paint film of excellent quality. Due to these advantages, it is possible to apply an anticorrosion coating film that is relatively thick and of excellent quality efficiently and at low cost compared to conventional methods such as brush coating or roller coating.

[Brief explanation of drawings]

FIGS. 1A to 1C are explanatory diagrams showing step by step the basic structure of the method of the present invention. Figures 2 to 7 show more specific embodiments of the method of the present invention, in which Figure 2 is a partially cutaway side view showing the formwork installed, Figure 3 is a plan view, and Figure 4 is a plan view. The figure is a vertical cross-sectional view of the spacer part, Figure 5 is a vertical cross-sectional view of the lower seal structure, Figure 6 is an explanatory diagram showing various structures for mold release, and Figure 7 is an explanation specifically showing the mold release method. It is a diagram. FIG. 8 is a longitudinal sectional view showing another embodiment of the spacer portion. In the figure, 1 is a steel pipe pile, 2 and 2 are formworks, 3 is an elastic sealing member, 4 is an injection port, 8 is a paint, 8' is a coating film, 14 is a spacer, 19 is a release film, 3
0 indicates an annular step, and 31 and 32 indicate members.

Claims (1)

[Claims] 1. In a method for anti-corrosion treatment of the outer surface of a steel pipe pile for supporting marine structures, a release film is provided in advance on the inner surface of a split formwork, and the formwork is separated from the outer circumferential surface of the steel pipe pile using a spacer. to have a predetermined gap,
In addition, the lower part and the outer circumferential surface of the steel pipe pile are connected by a compression type elastic seal in which the upper sealing material is thick, the lower sealing material is thin, and the annular step between both sealing materials is supported by the formwork component. It is attached to the outer periphery of the steel pipe pile while being sealed with a material, and a specific gravity of 1.5 is applied from the bottom of the formwork to the above gap.
~2.0 liquid hardening anticorrosive paint is injected and filled, and after the anticorrosive paint has hardened, the formwork is removed from the steel pipe pile by peeling off the formwork body from the release film adhered to the anticorrosion paint film, and the formwork is removed from the steel pipe pile on the outside surface of the steel pipe pile. A corrosion-proofing method for marine structures characterized by forming a coating film.