JPH09125437A - Anticorrosive coating structure of steel material and anticorrosive execution method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent electrochemical corrosion of a steel material and facilitate connection of a corrosion resistant metallic plate at an anticorrosive execution site. SOLUTION: The surface of a steel pipe pile 1 is coated with a mortar layer 13 and a titanium plate 7 in sequence. The lower end of the titanium plate 7 is laid on the fixing seat 2 for a form provided on the steel pipe pile 1 through an electrically insulative packing 9. And an insulative seal material 6 arranged in the fixing seat for the form is put between the titanium plate 7 and the steel pipe pile 1 to seal them water-tightly. The side ends of the titanium plate 7 are connected to each other by screwing nuts fixed to the inside face of one end side and bolts 11 inserted from the outside at the other end side 7b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anticorrosion coating structure and an anticorrosion construction method for a steel material of a steel structure constructed in water or on water, and in particular, a steel pipe and a steel sheet pile constituting a jetty, a quay wall and other structures. The present invention relates to a coating structure and an anticorrosion construction method for anticorrosion of steel materials such as the so-called tidal zone and splash zone.

[0002]

2. Description of the Related Art Structures constructed in water, such as the sea, are severely corroded by seawater and have a short service life.
Electrochemical galvanic protection and external power supply corrosion protection are applied, and each contributes effectively to the improvement of corrosion resistance. However, for corrosion protection of steel structures, seawater and air are alternately in contact with each other, so that they are susceptible to corrosion, so-called tidal zones and splash zones, the above-mentioned electrochemical methods cannot be applied. Therefore, various other anticorrosion methods and anticorrosion structures have been conventionally proposed.

As one of them, there is an anticorrosion structure in which concrete is directly adhered to the outer circumference of the steel pipe over the entire circumference. In this structure, the concrete is poor in impact resistance, so that a ship or the like hits it. There was a problem that the concrete was cracked by coming into contact with the concrete, and the water that had penetrated into the concrete from the crack caused early corrosion of the steel pipe. Therefore, Japanese Utility Model Application Laid-Open No. 52-94004 discloses an anticorrosion structure in which a mortar is filled in an anticorrosion cover surrounding a steel pipe pile.
In the gazette, the lower part of the frame made of spun fiber cloth surrounding the steel pipe pile is fastened and fixed to the steel pipe pile with a fixing band, and secured between the steel pipe pile and the steel pipe pile. A corrosion prevention device having a space portion filled with mortar or the like is disclosed in Japanese Patent Laid-Open No. 55-14515.
Disclosed are anticorrosion coatings obtained by winding a steel pipe pile with a sheet coated with a rust preventive agent, and tightening the rust preventive agent-coated sheet with a resin sheet provided with flange portions for joining bolts and nuts at both ends. However, in these conventional technologies,
Since the anticorrosion cover exposed to the outside is made of resin, cloth, etc., there is a problem that its own weather resistance is low, and the anticorrosion cover itself may be cracked or torn due to collision with a ship, driftwood or the like. There was a problem that it easily occurred.

Further, Japanese Utility Model Laid-Open No. 52-50507 discloses an anticorrosion cover for a steel pipe pile in which a release sheet made of synthetic resin is spirally attached to at least the inner surface of a cylindrical member. Since the synthetic resin sheet has low strength, this anticorrosion cover cannot be an effective anticorrosion means.

Further, in Japanese Unexamined Patent Publication No. 51-6308, the upper part of a tubular body made of FRP surrounding the steel pipe pile is hung on the steel pipe pile, and the lower part thereof is pressed by the steel pipe pile and the tubular body. An anticorrosion structure in which a deformed annular elastic body is provided, and mortar is injected between the steel pipe pile and the tubular body, and in Japanese Patent Laid-Open No. 51-102302, the upper portion is a steel pipe pile. A spacer for maintaining the distance between the FRP tubular body and the steel pipe pile is provided on the FRP tubular body, and a conical annular sealing body is provided under the tubular body to seal the gap with the steel pipe pile. Corrosion-proof structures in which mortar is injected between the tubular body and the steel pipe pile are described, respectively.
However, in any of these, there is a disadvantage that the structure of the anticorrosion structure becomes complicated and the lower part is not sufficiently sealed, and in the latter case, in the mortar,
Since spacers having different coefficients of thermal expansion are embedded and cracks and the like are likely to occur in the mortar, infiltration of seawater into the mortar cannot be sufficiently prevented.

[0006]

As described above,
In the conventional technology in which the anticorrosion cover and the like that come into direct contact with water are made of a spun fiber cloth resin sheet or the like, in addition to low weather resistance of the anticorrosion cover and the like, cracks and tears are likely to occur, It is impossible to maintain the anticorrosion performance for a long period of time.
In the conventional technology constituted by the cylindrical body made of steel, in addition to having a complicated structure, there is an inconvenience that the sealing property against injection mortar is not sufficient, and further, the rigidity of the anticorrosion cover is low and the filling density of the mortar is low. However, it was not possible to prevent the gradual permeation of seawater into the mortar because it could not be sufficiently increased.

Therefore, in order to solve the above problems of the prior art, the applicant first used a titanium plate having an excellent corrosion resistance and a high resistance to collision and wear as an outer skin layer. A coated anticorrosion body having a high liquid-tightness at the lower part of the coated anticorrosion body, which is made by filling an alkaline cement mortar having an initial pH of 10 or more between the surface of the structure and excellent anticorrosion performance, is registered as new model No. 3003173. As proposed.

The applicant further developed the technical contents of the above invention as Japanese Patent Application No. 7-55798 to further improve the liquid tightness between a steel pipe pile and a titanium plate as a corrosion resistant metal plate. We have proposed a corrosion-resistant coating structure that enhances and more reliably prevents the intrusion of water during that time.

[0009]

By the way, when a steel material such as a steel pipe pile or a steel sheet pile is covered with a corrosion resistant metal plate such as a titanium plate, for example, an existing steel pipe pile is surrounded by a titanium plate in a cylindrical shape, and In the case of connecting both sides of the titanium plate to each other, when the steel pipe pile and the coated titanium plate come into contact with each other, an electrochemical reaction occurs and there is a high possibility that the steel pipe pile is corroded inside the coated titanium plate. In addition, when performing anticorrosion construction that is often performed on existing steel pipe piles, steel sheet piles, and other steel materials that exist on the waterfront such as the coast, joining titanium plates, for example, at the construction site It was extremely difficult because the welding process at the factory was impossible.

The present invention has been made as a result of investigations aimed at solving such problems, and an object of the present invention is to provide a sufficiently electrical connection between a steel material and a corrosion-resistant metal plate covering the steel material. An object of the present invention is to provide an anticorrosion coating structure for steel materials and an anticorrosion construction method that facilitates joining at the anticorrosion construction site even if a titanium plate or the like is used as the corrosion-resistant metal plate, which is insulated. .

[0011]

According to the present invention, there is provided an anticorrosion coating structure for a steel material, wherein the steel material surface of a steel structure constructed in water or on water is successively coated with a mortar layer and a corrosion resistant metal plate layer. A steel frame-type fixed seat, which is mostly made of metal, is used to seat the lower end of the corrosion-resistant metal plate under insulation through an electrically insulating packing, and to secure the corrosion-resistant metal plate and the steel member together. The space between them is liquid-tightly sealed under insulation by an insulating sealing material disposed at least between them, and the side portion of the corrosion-resistant metal plate is The nut is fixed to the inner surface of the side portion in advance and the bolt is inserted into the other side portion from the outside, and the nuts are interconnected.

Here, the insulative sealing material is an underwater curing type epoxy resin which is polymerized and cured in a frame type fixed seat,
Alternatively, it is preferable that the mortar is solidified in the frame type fixed seat in order to achieve both electric insulation and liquid tightness between the steel material and the corrosion resistant metal material. Also preferably, an electrically insulating packing is made of soft plastic,
Rubber or closed-cell sponge rubber is provided with a groove for fitting a corrosion-resistant metal plate, and more preferably,
The packing is attached to the upper and lower ends of the corrosion resistant metal plate.

In the anticorrosion construction method of the present invention, after the frame type fixed seat is annularly attached around the steel pipe pile by welding, bolting, etc., the underwater cured epoxy resin or mortar is placed in the frame type fixed seat. While injecting the slurry,
A corrosion-resistant metal plate with electrical insulating packing attached to the lower end, preferably the upper end, is formed in a cylindrical shape around the steel pipe pile via an electrically insulating spacer, and the inside of one side portion of it is formed. For the nut previously fixed to, tighten the bolts that penetrated to the other side part to interconnect the both side parts, then push down the corrosion-resistant metal plate,
In a state where it is seated on the formwork fixed seat via the packing, it causes polymerization hardening of an underwater curing type epoxy resin or solidification of the mortar slurry, and thereafter, between the steel pipe pile and the corrosion resistant metal plate, the mortar slurry. Is filled and solidified while substituting the water existing between them.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 and 2 are a perspective sectional view and a longitudinal sectional view, respectively, of a main part illustrating a corrosion-resistant coating structure for a steel pipe pile as an example of a steel material. In providing such a covering structure, for example, at a required height position of the steel pipe pile 1, the frame type fixing seat 2 is tightened and fixed around the steel pipe pile 1 by the bolts and nuts 3, and above the frame type fixing seat 2. A plurality of spacers 4 made of an electrically insulating material such as mortar or plastic in the required anticorrosion coating area of
Are arranged at required intervals in each of the vertical direction and the circumferential direction.

Here, the frame type fixed seat 2 of this example has a small diameter portion 2a tightly tightened on the outer peripheral surface of the steel pipe pile 1 and a radius from the small diameter portion 2a, as shown in a partial vertical sectional view in FIG. It comprises a seat portion 2b which horizontally projects outward in the direction to receive the corrosion-resistant metal plate, and a large diameter portion 2c which stands up from the seat portion 2b. In addition, here, the spacers 4 are arranged such that the hook-shaped portions at the upper and lower end portions of the support wire 5 to which the plurality of spacers 4 are attached at intervals are provided on the outer peripheral surface of the steel pipe pile 1 at required intervals. By welding the spacers, a plurality of spacers can be attached at the same intervals at the same time, and the number of work steps at the anticorrosion site can be greatly reduced.

Here, an underwater curing type epoxy resin or a mortar slurry forming the insulating seal material 6 is provided between the steel pipe pile 1 and the large diameter portion 2c inside the frame type fixed seat 2, for example, between the steel pipe pile 1 and the large diameter portion 2c. Inject to the upper edge position of the large diameter portion 2c. On the other hand, a titanium plate 7 as an example of a corrosion-resistant metal plate is fitted with spacers 4 around the steel pipe pile 1 with electric insulating packings 8 and 9 fitted to the upper and lower ends thereof. Through a cylindrical shape, and
As shown in FIG. 4, the nut 10 preliminarily fixed to the inner surface of one side portion of the titanium plate 7 by the overlapping posture of the both side portions of the titanium plate 7 with respect to the other, Bolts 11 inserted from the outside are screwed into bolt holes provided in the side portions and tightened via washers 12, so that both side portions thereof are preferably interconnected in a liquid-tight manner. In addition, each side part of the titanium plate 7
Since such a tightening connection of 7a and 7b can be easily and efficiently performed under the pre-fixed state of the nut 10, it is possible to greatly reduce both the man-hours and equipment costs at the anticorrosion construction site. it can.

After such a cylindrical connection of the titanium plates 7,
The titanium plate 7 is pushed down, and its lower end is seated on the seat portion 2b of the frame type fixed seat 2 via the packing 9. According to this seated state, as clearly shown in FIG. 3, electrical conduction between the titanium plate 7 and the frame-type fixed seat 2 and the steel pipe pile 1 which are mostly made of metal is effectively performed by the packing 9. Be blocked. Then, under such a state, the epoxy resin in the frame type fixed seat is polymerized and cured, or the mortar slurry is solidified, so that the conduction between the lower end portion of the titanium plate 7 and the peripheral surface of the steel pipe pile 1 is achieved. It is sufficiently blocked, and at the same time, high liquid tightness is secured between them. Here, the electrical insulation between the other portion of the titanium plate 7 and the peripheral surface of the steel pipe pile is sufficiently secured by the spacer 4.

After the insulating sealing material 6 is formed by hardening the epoxy resin or solidifying the mortar slurry, a gap defined by the insulating sealing material 6, the steel pipe pile 1 and the titanium plate 7 is formed. The mortar slurry is poured into the inside of the mortar to completely replace it with water existing in the gap, and at the same time, the mortar slurry is filled into the gap and solidified to form the anticorrosive mortar layer 13. In addition,
Mortar containing a polymer may be used. In addition, in FIG.
Reference numeral 14 denotes an upper structure constructed by driving concrete into the upper portion including the upper packing 8 which can be retrofitted.

Although one embodiment of the present invention has been described above with reference to the drawings, steel sheet piles, steel pipe sheet piles, sheet pile cells and the like can be used as steel materials, and corrosion resistant metal sheets can be used. In addition to steel plates, stainless steel plates and the like can be applied.

[0020]

[Example] On a steel pipe pile 1 with a diameter of 1400 mm installed on the coast,
Attach the steel frame type fixed seat 2 with the bolt and nut 3,
An underwater curing type epoxy resin was injected into the frame type fixed seat until it reached the upper end thereof. On the other hand, a titanium plate 7 having a thickness of 0.5 mm is formed into a cylindrical shape with its lower end fitted with an electrically insulating rubber packing 9 having a U-shaped groove in a cross-sectional view, and the two plates are overlaid with each other. Titanium nuts that have been fixed to the inner surface of one side part in advance,
They were connected to each other with a titanium bolt inserted through the other side portion and seated on the frame type fixed seat 2. After the epoxy resin is hardened, a mortar slurry is filled into the gap of about 50 mm width partitioned by the insulating sealing material 6 made of the epoxy resin, the steel pipe pile 1 and the titanium plate 7 while being replaced with seawater. Solidified. Here, the gap between the steel pipe pile 1 and the titanium plate 7 was secured by a spacer 4 made of mortar or plastic.

After constructing the anticorrosion coating structure as described above, when the electrical insulation state between the steel pipe pile 1 and the titanium plate 7 was inspected every 6 months, no insulation leakage occurred.
When two years had passed, the corrosion-resistant coating structure was dismantled and the corrosion state of the steel pipe pile 1 was examined, and no measurable corrosion was found. And these things
Instead of the place described above, an electrically insulating packing 9 is used.
When the closed-cell sponge rubber packing with U-shaped groove is used, the insulating seal material 6 is formed by mortar solidified in the frame-type fixed seat, and the spacer 4 is (mortar, plastic) Was also exactly the same.

[0022]

As described above, according to the present invention, by using the corrosion-resistant metal plate as the outermost layer, it does not cause any problems with respect to weather resistance, covering power, etc., of course, is extremely tough, and has an impact, It has a high resistance to deformation and peeling, and can provide a corrosion-resistant coating structure with excellent durability without deterioration by deterioration. In addition, here, a corrosion-resistant metal plate, for example, a titanium plate, an electrically insulating packing,
This is also possible, for example, via a packing made of rubber, soft plastic, highly airtight closed-cell sponge rubber, etc.
Most of them provide high insulation by being seated on a frame type fixed seat made of a metal material. Therefore, a steel material whose electrochemical potential is base to the titanium plate becomes an anode to the titanium plate. Therefore, the steel material is not melted or corroded. That is, the problem of corrosion due to the contact of dissimilar metals is sufficiently solved. Moreover, here, the insulating seal material hardened or solidified in the frame type fixed seat directly electrically insulates the lower end portion of the corrosion-resistant metal plate from the steel material, so that the corrosion of the steel material is prevented. It can be prevented more effectively, and at the same time, based on the adhesion of the insulating sealing material to both of them,
It is possible to more effectively eliminate the risk of seawater entering between them. Furthermore, by firmly fixing the nut to the inner surface of one side portion of the corrosion-resistant metal material by electric welding or the like which is factory-installed, the side portions of the corrosion-resistant metal plate in the anticorrosion construction site are mutually fixed. Since the connection can be performed easily, easily, and efficiently by tightening the bolts, the number of man-hours for anticorrosion construction can be reduced, and the facility cost can be greatly reduced. In addition, in the gap between the steel plate and the corrosion-resistant metal plate, the mortar layer formed by sufficiently substituting with water exerts an excellent electrical insulation function together with the spacer to effectively protect the steel plate from corrosion. , Make the anticorrosion coating structure extremely strong.

[Brief description of the drawings]

FIG. 1 is a cross-sectional perspective view of essential parts showing an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view of an essential part showing an embodiment of the present invention.

FIG. 3 is a partial vertical cross-sectional view showing a frame-shaped fixed seat and a seated state of a corrosion-resistant metal plate thereon.

FIG. 4 is a transverse cross-sectional view showing a connected state of respective side portions of a corrosion-resistant metal plate.

[Explanation of symbols]

 1 Steel pipe pile 2 Frame type fixed seat 2a Small diameter part 2b Seat part 2c Large diameter part 3 Bolt / nut 4 Spacer 5 Support wire 6 Insulating sealing material 7 Titanium plate 7a, 7b Side part 8, 9 Packing 10 Nut 11 Bolt 13 Mortar layer

Claims (5)

[Claims] 1. An anticorrosion coating structure in which a steel material surface of a steel structure constructed in water or on water is sequentially covered with a mortar layer and a corrosion-resistant metal plate layer, and a frame-type fixed seat provided on the steel material. The lower end of the corrosion-resistant metal plate is seated via an electrically insulating packing, and the space between the corrosion-resistant metal plate and the steel material is liquid-tightly sealed by an insulating seal material arranged in the frame type fixed seat. The side edges of the corrosion-resistant metal plate are interconnected by screwing a nut fixed to the inner surface of one side edge and a bolt inserted from the outside to the other side edge. Anticorrosion coating structure of steel. 2. The anticorrosion coating structure for a steel material according to claim 1, wherein the insulative sealing material is formed of an underwater curing type epoxy resin which is polymerized and cured in a frame type fixed seat. 3. The anticorrosion coating structure for steel according to claim 1, wherein the insulating sealing material is formed of mortar solidified in a frame type fixed seat. 4. An electrically insulating packing made of soft plastic, rubber or closed-cell sponge rubber and having a groove for fitting the corrosion resistant metal plate is attached to the lower end of the corrosion resistant metal plate. The anticorrosion coating structure for steel according to item 1. 5. A frame type fixed seat is annularly attached around a steel pipe pile, and an underwater curing type epoxy resin or mortar slurry is injected into the frame type fixed seat, and an electrically insulating packing is attached to the lower end. A corrosion-resistant metal plate is formed in a cylindrical shape around a steel pipe pile through an electrically insulating spacer, and a nut that is pre-fixed to the inner surface of one side part of the steel plate penetrates the other side part. Tighten the bolts to interconnect the both side parts, then push down the corrosion resistant metal plate, and while it is seated on the frame type fixed seat via the packing, polymerization of the underwater curing type epoxy resin is performed. It is characterized by hardening or causing solidification of the mortar slurry, and then filling and solidifying the mortar slurry between the steel pipe pile and the corrosion-resistant metal plate while replacing the water present therein. Anticorrosion construction method for steel materials.