JP7201464B2 - Steel structure repair method - Google Patents

Description

The present invention uses a sheet-like reinforcing fiber-containing material containing continuous reinforcing fibers (hereinafter referred to as "fiber sheet") to prevent corrosion of bridges, piers, chimneys, etc., ships, vehicles, aircraft, etc. The present invention relates to a method for repairing a steel structure, which is simply repaired to reinforce a steel structure whose thickness has been reduced.

In recent years, as a method for repairing and reinforcing existing or newly constructed steel structures, a carbon fiber sheet adhesion method or an aramid fiber sheet adhesion method, in which a continuous reinforcing fiber sheet such as a carbon fiber sheet or an aramid fiber sheet is pasted or wound on the surface, is used. There are continuous fiber sheet bonding methods such as There is also a construction method in which a fiber sheet in which a continuous fiber bundle is impregnated with an uncured matrix resin is adhered and then cured.

Furthermore, in order to omit resin impregnation on site, FRP plates are made by bonding factory-produced plate-shaped fiber reinforced plastic materials (FRP plates) with a thickness of 1 to 2 mm and a width of about 5 cm using a putty-like adhesive resin. Adhesion methods have also been developed.

Referring to FIGS. 11(a) to 11(f), the method of repairing and reinforcing a steel structure described in Patent Document 1 and currently being actually constructed will be described. According to this repair and reinforcement method, ,
(a) The fragile portion 201a of the surface to be reinforced (that is, the surface to be bonded) 201 of the steel structure 200 is removed by a grinding means 50 such as a disk sander, and the surface to be bonded 201 of the steel structure 200 is subjected to surface treatment. (FIGS. 11(a) and (b)).
(b) A primer 203 is applied to the ground surface 202 (FIG. 11(c)).
(c) A polyurea resin putty agent 204 is applied to the surface 201 to be adhered to which the primer 203 is applied and cured to form an elastic layer 204 (FIG. 11(d)).
(d) An adhesive 205 is applied on the elastic layer 204, and the fiber sheet 1 is pressed against this surface to adhere to the surface 202 of the concrete structure 200 to be reinforced through the elastic layer 204 (Fig. 11(e)). ).
have a process.

Here, in reinforcement work on steel structures built outdoors, there is concern that fiber sheets, resins, etc. that are adhered to the steel structure and form the surface layer of the steel structure may deteriorate due to ultraviolet rays, water, and oxygen. be done.

Therefore, a coating film 206 is formed by coating the surface area of the reinforced steel structure (FIG. 11(f)).

Japanese Patent No. 5380551

According to the method for repairing and reinforcing a steel structure described in Patent Document 1, peeling of the fiber sheet 1 can be prevented, and a sufficient reinforcing effect can be obtained even in a high-temperature environment such as sunlight. Further, the durability of the fiber sheet 1 used in such a repair and reinforcement method is said to be 20 to 30 years. Therefore, the fiber sheet is peeled off from the steel structure and replaced with a new one, for example, when the steel structure is repainted periodically every 20 to 30 years.

On the other hand, for example, steel structures are subject to close visual inspections every five years, and during these visual inspections, there are cases in which steel material defects due to partial corrosion thinning are found in the steel structures. In this case, although it has not yet reached the level of full repair and reinforcement of the steel structure, it may be considered preferable to carry out partial repair and reinforcement as soon as possible.

In such a case, in order to reinforce the entire area of the steel structure with a fiber sheet, as is done when repainting, preparation and transportation of the reinforcing material are large-scale, and considerable construction time is required. incurs construction costs. For example, it takes several days to perform the above steps (a) to (e), and in a steel structure built outdoors, as described above, fiber sheets, resins, etc. are exposed to ultraviolet rays, water, In order to prevent deterioration due to oxygen, painting (step (f) above) is essential. There is an intermediate coating and a top coating for painting, and there is a problem that the construction period is longer due to this.

Therefore, if a local defect is found during a close visual inspection every five years, it can be repaired in a short time, for example, without waiting for the entire fiber sheet to be replaced at the time of periodic repainting. There is a demand for a simple repair method that can complete construction in a short time of 10 minutes or less.

The present inventors conducted many research experiments to realize a simple reinforcement method for steel structures, and as a result, it was found that, in particular, the conventional repair and reinforcement method for steel structures using fiber sheets requires a long construction time. Repair work that guarantees sufficient weather resistance for a period of about 10 years, and therefore, reinforcement strength, by eliminating the painting process as described above and instead covering and protecting the repaired part with a weather-resistant protective film. In addition, it was found that the protective film could be easily replaced if necessary. Therefore, if the protective film is replaced as necessary at the time of close visual inspection every five years, the weather resistance of the fiber sheet using carbon fiber or the like is guaranteed within the permissible usage period of 20 to 30 years. It was found that a simple repair method can be provided that does not lower the reinforcement strength and can reduce the construction cost as much as possible.

The present invention is based on such novel findings of the present inventors.

The object of the present invention is to use a weather-resistant protective film instead of painting, so that construction can be completed in a short period of time, such as within 10 minutes. A simple steel structure that can achieve a sufficient reinforcing effect and, if necessary, can be replaced at the time of close visual inspection every five years, and can reduce construction costs as much as possible. is to provide a repair method for

Another object of the present invention is to provide a method for repairing a steel structure that facilitates transportation of repair materials to the site and simple construction work.

The above object is achieved by a method for repairing a steel structure according to the present invention. In summary, the first aspect of the present invention is a method for repairing a steel structure in which a fiber sheet containing reinforcing fibers is adhered onto the surface of a steel structure having a defective portion whose thickness has been reduced due to corrosion or the like to integrate the fiber sheet. hand,
(a) a step of surface conditioning a partial region including the defective portion on the surface of the steel structure to remove paint and rust;
(b) bonding the fiber sheet with an adhesive to a region of the conditioned steel structure that includes the defective portion but is smaller than the entire conditioned region;
(c) affixing a protective film covering the fiber sheet, the texture-conditioned area around the fiber sheet, and the non-texture-conditioned area of the structure surface;
A method for repairing a steel structure characterized by having

According to one embodiment of the first aspect of the present invention, the fiber sheet used in the step (b) and the protective film used in the step (c) are integrally bonded in advance, and the ( The bonding of the fiber sheet in the step b) to the surface-conditioned region and the bonding of the protective film to the peripheral region of the fiber sheet in the step (c) are performed at the same time.

According to another embodiment of the first invention, the adhesive used in the step (b) is a thermosetting resin or a thermoplastic resin. Preferably, the thermosetting resin is a room temperature or thermosetting epoxy resin, vinyl ester resin, MMA resin, acrylic resin, unsaturated polyester resin, or phenolic resin, and the thermoplastic resin is a thermosetting resin. plastic epoxy, nylon, or vinylon.

A second aspect of the present invention is a method for repairing a steel structure by bonding and integrating a fiber sheet containing reinforcing fibers onto the surface of the steel structure having a defective portion whose thickness has been reduced due to corrosion or the like, comprising:
(a) a step of surface conditioning a partial region including the defective portion on the surface of the steel structure to remove paint and rust;
(b) a weather resistant sheet of silicone overlying the conditioned areas of the steel structure and areas of the steel structure surface that are not conditioned around the conditioned areas; a step of adhering a resin sheet adhesive;
(c) arranging the fiber sheet so as to correspond to an area narrower than the entire area of the steel structure that has been subjected to surface conditioning, and bonding the silicone-based resin sheet; a step of pressing and bonding the fiber sheet onto the agent;
(d) covering the fiber sheet with a protective film;
A method for repairing a steel structure characterized by having

According to an embodiment of the second aspect of the present invention, the fiber sheet used in the step (c) and the protective film used in the step (d) are integrally bonded in advance, and the ( d) Skip the steps.

According to another aspect of the first and second aspects of the present invention, the fiber sheet is a fiber sheet in which continuous reinforcing fibers aligned in one direction are fixed to each other with a wire rod fixing member, or the fiber sheet The sheet is a fiber sheet obtained by impregnating a continuous reinforcing fiber sheet aligned in one direction with a resin and curing the resin.

According to another aspect of the first and second aspects of the present invention, the fiber sheet includes a plurality of continuous fiber-reinforced plastic wires in which the reinforcing fibers are impregnated with a matrix resin and hardened, and which are arranged in a cord shape in the longitudinal direction. In this case, the matrix resin is a thermosetting resin or a thermoplastic resin. In addition, the thermosetting resin is a room temperature or thermosetting epoxy resin, vinyl ester resin, MMA resin, acrylic resin, unsaturated polyester resin, or phenol resin, and the thermoplastic resin is a thermoplastic resin. epoxy resin, nylon, or vinylon.

According to another aspect of the first and second aspects of the present invention, the fiber sheets are laminated and bonded in a plurality of layers.

According to other embodiments of the first and second aspects of the present invention, the reinforcing fibers are carbon fibers, glass fibers, basalt fibers; metal fibers such as boron fibers, titanium fibers, steel fibers; Organic fibers such as PBO (polyparaphenylene benzobisoxazole), polyamide, polyarylate, and polyester;

According to another embodiment of the first and second aspects of the present invention, the protective film is a weather-resistant acrylic resin film, vinyl chloride resin film, polycarbonate resin film, or polyolefin resin film as a base film. It has a film or fluorine resin film. Also, according to another embodiment, the protective film has an adhesive layered on the base film.

According to the steel structure repair method of the present invention, by using a weather-resistant protective film instead of painting, construction can be completed in a short period of time, for example, within 10 minutes, and can be completed in 5 years. A sufficient reinforcing effect can be achieved until every close visual inspection, and furthermore, if necessary, it is possible to replace it at the close visual inspection every 5 years, and construction costs are reduced as much as possible. can do. In addition, the steel structure repair method of the present invention facilitates transportation of the repair material to the site, and also facilitates the construction work.

1(a) and 1(b) are diagrams for explaining the method of repairing a steel structure according to the present invention, FIG. 1(a) being a perspective view and FIG. 1(b) being a cross-sectional view. . FIG. 2 is a diagram showing an example of a fiber sheet that can be used in the steel structure repair method of the present invention. FIG. 3 is a diagram showing another embodiment of a fiber sheet that can be used in the steel structure repair method of the present invention. FIG. 4 is a perspective view showing an example of a fiber sheet that can be used in the steel structure repair method of the present invention. 5(a) and 5(b) are cross-sectional views showing examples of fiber-reinforced plastic wires forming a fiber sheet that can be used in the steel structure repair method of the present invention. FIGS. 6(a) and 6(b) are perspective views showing another embodiment of the fiber sheet that can be used in the steel structure repair method of the present invention. FIGS. 7(a) to (e) are process diagrams for explaining an embodiment of the steel structure repair method of the present invention. FIG. 8(a) is a cross-sectional view showing another example of the protective film used in the steel structure repair method of the present invention, and FIGS. FIG. 4 is a cross-sectional view showing an example of a fiber sheet to which a protective film is adhered, which is used in another example of the repair method; FIGS. 9(a) and 9(b) are diagrams for explaining the method for repairing a steel structure according to the present invention, FIG. 9(a) being a perspective view and FIG. 9(b) being a cross-sectional view. . FIGS. 10(a) to 10(f) are process diagrams for explaining another embodiment of the steel structure repair method of the present invention. FIGS. 11(a) to 11(f) are process diagrams illustrating an example of a conventional method for reinforcing and repairing a steel structure.

Hereinafter, the method for repairing a steel structure according to the present invention will be described in more detail with reference to examples.

Example 1
A first embodiment of a method for repairing a steel structure according to the present invention will be described with reference to FIGS. The present invention is a method of repairing a steel structure by bonding and integrating a fiber sheet containing reinforcing fibers onto the surface of the steel structure having a defective portion whose thickness has been reduced due to corrosion or the like. According to this embodiment, the steel structure repair method of the present invention includes:
(a) a step of surface conditioning a partial region including the defective portion 103 on the surface of the steel structure 100 to remove paint and rust;
(b) a step of bonding the fiber sheet 1 with an adhesive 105 to a region smaller than the entire conditioned region 104, including the defective portion of the conditioned steel structure;
(c) Affixing a protective film 106 covering the fiber sheet 1, the surface-conditioned area (ΔL104) around the fiber sheet 1, and the non-surface-conditioned area (ΔL106) on the surface of the structure. process and
characterized by having The fiber sheet used in the step (b) and the protective film 106 used in the step (c) are integrally bonded in advance, and the steps (b) and (c) are performed simultaneously. can also

Next, each material used in the present invention will be described.

(fiber sheet)
Various forms of the fiber sheet 1 can be used in the present invention. Examples of the fiber sheet 1 will be specifically described as specific examples 1 to 3, but the form of the fiber sheet 1 used in the present invention is not limited to those shown in these specific examples.

Example 1
FIG. 2 shows an example of a fiber sheet 1 that can be used in the present invention. The fiber sheet 1 is a non-resin-impregnated fiber sheet 1A formed by pulling continuous reinforcing fibers f in one direction to form a sheet.

That is, the fiber sheet 1A can have a configuration in which a reinforcing fiber sheet made of continuous reinforcing fibers f aligned in one direction is held by a wire fixing member 3 such as a mesh-like support sheet. For example, when carbon fibers are used as the reinforcing fibers f, a plurality of single fiber bundles not impregnated with a resin, in which 6000 to 24000 single fibers (carbon fiber monofilaments) f having an average diameter of 7 μm are converged, are arranged in parallel in one direction. used in line with The fiber basis weight of the carbon fiber sheet 1A is usually 30-1000 g/m ² .

The surface of the warp threads 4 and the weft threads 5 constituting the mesh-like support sheet as the wire fixing material 3 is pre-impregnated with a low-melting thermoplastic resin, and the mesh-like support sheet 3 is arranged in a sheet form. The fiber is laminated on one side or both sides and heated and pressurized to weld the warp yarn 4 and weft yarn 5 of the mesh-like support sheet 3 to the carbon fiber sheet.

The mesh-like support sheet 3 may be formed by orienting glass fibers triaxially in addition to the biaxial structure, or may be formed by arranging the glass fibers in one direction and using only the weft yarns 5 orthogonal to the carbon fibers. It can also be adhered to the arranged carbon fibers which are so-called uniaxially oriented and aligned in the sheet form.

As the thread of the wire rod fixing member 3, a double structure composite fiber having a glass fiber in the core and a heat-sealable polyester having a low melting point disposed around the core is also preferably used. .

Example 2
Further, as shown in FIG. 3, the fiber sheet 1 is obtained by impregnating a reinforcing fiber sheet in which a plurality of reinforcing fibers f are aligned in one direction, for example, a fiber sheet 1A as shown in FIG. can also be a plate-like fiber sheet (so-called FRP plate) 1B in which is cured.

In the fiber sheets 1A and 1B described in Specific Examples 1 and 2 above, the reinforcing fibers f are not limited to carbon fibers, but are glass fibers, basalt fibers, and metal fibers such as boron fibers, titanium fibers, and steel fibers. Furthermore, organic fibers such as aramid, PBO (polyparaphenylenebenzobisoxazole), polyamide, polyarylate, and polyester; can be used singly or in hybrid form by mixing multiple types.

Further, as the resin Re in the case of the fiber sheet 1B in Specific Example 2, a thermosetting resin or a thermoplastic resin can be used. , vinyl ester resins, MMA resins, acrylic resins, unsaturated polyester resins, phenolic resins, etc. are preferably used, and as thermoplastic resins, thermoplastic epoxy resins, nylon, vinylon, etc. can be preferably used. . The resin impregnation amount is 30 to 70% by weight, preferably 40 to 60% by weight.

Example 3
Further, as shown in FIGS. 4 and 5, as the fiber sheet 1, a plurality of fine-diameter continuous fiber-reinforced plastic wires 2 impregnated with a matrix resin Rf and hardened are aligned in the longitudinal direction in a blind shape. , a fiber sheet (strand sheet) 1C in which each wire rod 2 is fixed with a wire rod fixing member 3 can also be used.

The fiber-reinforced plastic wire 2 has a substantially circular cross-sectional shape (FIG. 5(a)) with a diameter (d) of 0.5 to 3 mm, or a width (w) of 1 to 10 mm and a thickness (t) of 0. It may have a substantially rectangular cross-sectional shape (FIG. 5(b)) of 1 to 2 mm. Of course, various other cross-sectional shapes can be used as desired.

As described above, in the fiber sheet 1 aligned in one direction and made into a blind shape, the wires 2 are closely spaced apart from each other by a gap (g) of 0.05 to 3.0 mm, and are fixed by the wire fixing member 3. Fixed.

Also in the case of the fiber sheet 1C, the reinforcing fibers f include carbon fiber, glass fiber, basalt fiber; metal fibers such as boron fiber, titanium fiber, steel fiber; , polyamide, polyarylate, polyester, etc.; Further, the matrix resin Rf impregnated in the fiber-reinforced plastic wire 2 can be a thermosetting resin or a thermoplastic resin. Vinyl ester resins, MMA resins, acrylic resins, unsaturated polyester resins, phenol resins, and the like are preferably used, and thermoplastic epoxy resins, nylon, vinylon, and the like can be preferably used as thermoplastic resins. The resin impregnation amount is 30 to 70% by weight, preferably 40 to 60% by weight.

As a method of fixing each wire 2 with a wire fixing member 3, for example, as shown in FIG. A wire made into a sheet form consisting of two pieces, ie, a continuous wire sheet, can be driven perpendicularly to the wire at regular intervals (P) and knitted. The pitch (P) of the weft threads 3 is not particularly limited, but is usually selected in the range of 10 to 100 mm, taking into account the handleability of the manufactured fiber sheet 1 .

At this time, the weft thread 3 is a thread obtained by bundling a plurality of glass fibers or organic fibers having a diameter of 2 to 50 μm, for example. As the organic fibers, nylon, vinylon and the like are preferably used.

As another method for fixing each wire 2 in a blind shape, a mesh support sheet can be used as the wire fixing member 3, as shown in FIG. 6(a).

That is, the above-described specific example in which a plurality of wire rods 2 arranged in a sheet form, that is, one side or both sides of the wire rod sheet are made of glass fiber or organic fiber having a diameter of 2 to 50 μm, for example. 1 may be supported by a mesh-like support sheet 3 having the same structure as described in 1 above.

Furthermore, as another method of fixing each wire 2 in a blind shape, as shown in FIG. can be used. The flexible strip 3 is arranged on one side or both sides of a plurality of fiber reinforced plastic wires 2 in a direction perpendicular to the longitudinal direction of each fiber reinforced plastic wire 2 arranged in a sheet shape. Paste and fix.

That is, as the flexible strip 3, an adhesive tape such as vinyl chloride tape, paper tape, cloth tape, or non-woven tape having a width (w1) of about 2 to 30 mm is used. These tapes 3 are usually applied perpendicularly to the longitudinal direction of each fiber-reinforced plastic wire 2 at intervals (P) of 10 to 100 mm.

Furthermore, as the flexible strip 3, a strip of thermoplastic resin such as nylon or EVA resin is heat-sealed to one side or both sides in a direction perpendicular to the longitudinal direction of the wire 2. be done.

As for the length (L) and width (W) of the fiber sheet 1 shown in Specific Examples 1 to 3 above, the overall width (W) is generally 100 to 1000 mm, and the length (L) is a strip shape of about 1 to 5 m. or 100 m or more, but in the present invention, in order to improve portability, the length (L) of the fiber sheet 1 is not limited to this size, but is not limited to this size. , Width (W) is used by cutting to a size in the range of 150 to 400 mm. .

(Reinforcement method)
Next, a first embodiment of the steel structure repair method of the present invention will be described with reference to FIGS. 1(a), (b) and FIGS. According to the present invention, the fiber sheet 1 manufactured as described above is cut into a size that is suitable for portability, and is used to repair a defective portion of a steel structure whose thickness has been reduced due to corrosion or the like. conduct.

(First step)
As shown in FIG. 7(a), a steel structure 100 may have a defective portion 103 with reduced thickness due to corrosion, etc., and this defective portion 103 is repaired by the method of the present invention. The defect repaired by the present invention is assumed to have a defect depth (t) of approximately 2 mm, a length of 5 to 100 mm, and a width of approximately 5 to 100 mm.

According to the present invention, first, as shown in FIG. 7(b), the surface 101 of the steel structure 100 is ground-treated in a region to be repaired (surface preparation region) 104 including the defective portion 103 . That is, the surface treatment is performed by removing the old coating film and rust on the coating 102 using an electric tool or a hand tool, that is, a surface treatment of about two types of cleaning, that is, surface adjustment. As a cleaning tool, a battery-type disk sander or the like is portable and can be suitably used for small-scale surface preparation work.

The fiber sheet 1 used in the present invention is easy to carry, and in consideration of the required work time required for repair work, etc., in this embodiment, the thickness (T) per sheet of the fiber sheet 1 is is 1 to 3 mm, and length (L)×width (W) is about 300 mm×200 mm. Therefore, the surface adjustment area 104 (L104a, L104b) where the surface adjustment is performed is an area that is wider than the size (L×W) of the fiber sheet 1 to be used by the marginal length (ΔL104). The keren extra length (ΔL104) is 5 to 50 mm, usually about 20 mm.

(Second step)
As shown in FIGS. 7(c) and 7(d), an adhesive 105 is applied to the surface-adjusted region 104 after surface preparation. The adhesive 105 is preferably applied only to a narrower area than the entire surface-conditioned area within the range of the surface-conditioned area 104 (L104a, L104b) including the defective portion 103. In some cases, the adhesive 105 is applied after masking. You can also However, there is no problem even if it protrudes from the range of the substrate adjustment area 104 and slightly protrudes into the active film portion of the coating 102 around the substrate adjustment area.

Next, the fiber sheet 1 is pressed against the surface to which the adhesive 105 is applied, and adheres to the surface 102 of the steel structure.

According to the steel structure repair method of the present invention, for example, as the fiber sheet 1, the fiber sheet 1A produced by aligning the reinforcing fibers f described in the above specific example 1 in one direction can be used, An adhesive 105 is used to bond and integrate the damaged portion of the surface of the prepared steel structure. At this time, the adhesive (matrix resin) impregnation of the fiber sheet 1A with the adhesive can be performed simultaneously with the adhesion of the fiber sheet 1A to the steel structure.

When repairing the steel structure 100, for the member (structure) that mainly receives the bending moment and the axial force, the orientation direction of the reinforcing fibers should be generally aligned with the principal stress direction of the tensile stress or compressive stress generated by the bending moment. By bonding, the fiber sheet 1 effectively bears the stress, and even though it is a simple repair method, it is possible to efficiently improve the load bearing capacity of the structure.

When bending moments act in two directions perpendicular to each other, two or more fiber sheets 1 are laminated and bonded so that the orientation direction of the reinforcing fibers f of the fiber sheet 1 substantially coincides with the principal stress generated by the bending moment. By doing so, the load-bearing capacity can be efficiently improved.

Moreover, when a large amount of reinforcement is required, it is possible to adhere a plurality of layers of the fiber sheet 1 to the surface of the structure. Usually, the fiber sheet 1 is produced by laminating two layers so as to correspond to steel of 1 mm.

A thermosetting resin or a thermoplastic resin can be used as the adhesive 105. Thermosetting resins include room-temperature-curing or thermosetting epoxy resins, vinyl ester resins, MMA resins, acrylic resins, Unsaturated polyester resins, phenolic resins, and the like are preferably used, and thermoplastic epoxy resins, nylon, vinylon, and the like can be preferably used as thermoplastic resins. The resin impregnation amount is 30 to 70% by weight, preferably 40 to 60% by weight.

Although the adhesive 105 has been described as being applied onto the surface adjustment area 104, it can of course be applied to the fiber sheet 1, and both the surface of the surface adjustment area 104 and the adhesive surface of the fiber sheet 1 can be applied. You can apply it on top.

As described above, in the present invention, the impregnation work for the fiber sheet 1 is carried out on site. As a result, it is possible to reduce the weight by making it a capacity that can be used only once or multiple times, and by eliminating the need for stirring a large amount of chemicals on site, which was done in conventional repair and reinforcement work. On-site work becomes easier and the construction period can be shortened.

In the above description, the fiber sheet 1 is the resin-unimpregnated fiber sheet 1A described in Specific Example 1, but the fiber sheet 1 is a plate-shaped fiber impregnated with the resin described in Specific Example 2 and cured. It can also be a sheet, that is, an FRP plate 1B. In the case of the FRP plate 1B as well, in consideration of portability and workability, the size of the FRP plate 1B can be 300 mm x 200 mm in length (L) x width (W) as described above. In order to prevent injury and relieve stress concentration, it is preferable that the portion is rounded with a radius of about 10 mm. Generally, in the case of the FRP plate 1B, one layer has a thickness of 1 to 2 mm, which corresponds to steel of 2 to 4 mm.

For example, according to research experiments by the present inventors, the FRP plate (CFRP plate) 1B using carbon fiber has a thickness of 0.8 mm, 1.2 mm, and 2 mm, and has a thickness of 400 MPa (yield of steel material SM570). 88% of the allowable value, 1.56 times the allowable value), and it was found that the strength was sufficient for practical use. Since the CFRP plate 1B has an elastic modulus of 350 GPa, the plate thickness corresponding to a defect of 2 mm is 1.2 mm.

Further, the impregnated resin of the FRP plate 1B is hardened, and it is difficult to fit and adhere to an internal corner. Therefore, when it is necessary to repair such curved portions such as internal corners, for example, by using a thermoplastic resin as the impregnating resin for the FRP plate 1B, that is, for example, at about 80 to 100 ° C. It is made installable by using deformable field processable thermoplastics.

Furthermore, as the fiber sheet 1, a fiber sheet formed by arranging a plurality of fiber-reinforced plastic wires 2 in a threaded manner in the longitudinal direction, that is, a strand sheet 1C, as described in Example 3, may be used. In this case, the adhesive 105 is also filled in the gaps (g) between the wires 2, 2 of the strand sheet 1C, and the strand sheet 1C is adhered to the base adjustment region 104. FIG.

(Third step)
Next, as shown in FIGS. 7(d) and (e), a protective film 106 is attached to the surface of the steel structure covering the fiber sheet 1 adhered to the steel structure. The protective film 106 covers the fibrous sheet 1 and also extends to the surface of the unconditioned steel structure around the fibrous sheet 1 to apply a predetermined amount of active film to the non-removed paint areas. They are overlapped, that is, adhered with an adhesive with a wrap length (ΔL106). That is, the fiber sheet 1, the surface-conditioned region 104 (the region with the excess keren length ΔL104) around the fiber sheet 1, and the region where the surface of the structure is not surface-conditioned (the region with the wrap length ΔL106), is covered with a protective film 106. The wrap length ΔL106 is about 20 to 100 mm, usually about 50 mm.

The protective film 106 protects the fiber sheet 1 from ultraviolet rays, and blocks the area between the fiber sheet 1 and the unremoved active film (that is, the keren surplus length ΔL104) from water and oxygen. It is for For example, as shown in FIG. 7D, the protective film 106 is a base film such as a weather-resistant acrylic resin film, vinyl chloride resin film, polycarbonate resin film, polyolefin resin film, or fluorine resin film. 106a and an adhesive 106b for adhering the base film 106 to the fiber sheet 1 or the like. As the protective film 106, for example, a protective film (trade name: "3M Scotchcal Film ETM series") manufactured by 3M Japan Ltd., in which an acrylic pressure-sensitive adhesive is integrally formed on a vinyl chloride resin film, can be suitably used. As shown in FIG. 8A, this protective film includes a vinyl chloride resin film 106a having weather resistance as a base film, an acrylic pressure-sensitive adhesive 106b as a pressure-sensitive adhesive, and a further weather-resistant film as a surface layer. and a surface protective layer (acrylic resin film) 106c, and a release paper 106d is attached to the adhesive surface. The thickness of the protective film 106 is 0.14 mm without the release paper 106c. At the time of use, the release paper 106d can be peeled off at the work site and attached to the fiber sheet 1 or the like, which is convenient. According to the results of research experiments by the present inventors, such a protective film is considered to have weather resistance for at least 10 years, usually about 10 years. Moreover, it can be easily peeled off from the fiber sheet 1 or the like, if necessary, after being attached.

The fiber sheet 1 used in the step (c) and the protective film 106 used in the step (d) can be integrally adhered in advance as shown in FIG. 8(b). . In this case, the step (c) and the step (d) are performed simultaneously, that is, the fiber sheet 1 is adhered to the surface adjustment region 104 with the adhesive 105, and the protective film 106 is adhered to the region of the keren surplus length ΔL104. and the active film portion (area of ΔL106) of the coating area around it. When the protective film 106 is adhered to the fiber sheet 1 in advance in this way, a release paper is adhered to the area protruding from the fiber sheet 1 before work at the site, and is removed at the time of work at the site. You can peel off the paper and use it.

Example 2
A second embodiment of the steel structure repair method according to the present invention will now be described with reference to FIGS. 9(a), (b) and FIGS. In this embodiment, as in the first embodiment, a fiber sheet 1 containing reinforcing fibers is bonded and integrated on the surface of a steel structure 100 having a defective portion due to corrosion or the like. It is a repair method for steel structures that According to this embodiment, the steel structure repair method of the present invention includes:
(a) a step of surface conditioning a partial region including the defective portion 103 on the surface of the steel structure 100 to remove paint and rust;
(b) a sheet of weather-resistant silicone system over the conditioned area 104 of the steel structure and the unconditioned steel structure surface area (ΔL106) surrounding the conditioned area; a step of adhering the resin sheet adhesive 105;
(c) The fiber sheet 1 is arranged so as to correspond to a region narrower than the entire region 104, which includes the damaged portion 103 of the steel structure that has been surface-conditioned, and the silicone-based resin sheet adhesive 105 is applied. a step of pressing and bonding the fiber sheet 1 thereon;
(d) a step of covering the fiber sheet 1 and attaching a protective film 106;
characterized by having The fiber sheet 1 used in the step (c) and the protective film 106 used in the step (d) are integrally adhered in advance, and the step (d) can be omitted.

Next, with reference to FIGS. 9(a), (b) and FIGS. 10(a) to (f), a second embodiment of the steel structure repair method of the present invention will be described in more detail. According to the present invention, the fibrous sheet 1 described above in Example 1 is used to repair for reinforcement the damaged portions of the steel structure whose thickness has been reduced due to corrosion or the like.

(First step)
As in the first embodiment, as shown in FIG. 10(a), in the present embodiment, a damaged portion 103 having a reduced thickness due to corrosion or the like, which is formed in a part of the steel structure 100, is repaired. It is assumed that the defect depth (t) of this defect portion is approximately 2 mm, the length is 5 to 100 mm, and the width is approximately 5 to 100 mm.

Also in this embodiment, first, as shown in FIG. 10(b), a surface treatment is performed on a region to be repaired (surface preparation region) 104 including the defective portion 103 on the surface 101 of the steel structure 100 . That is, the surface treatment is performed by removing the old coating film and rust in the coating 102 using an electric tool or a hand tool, that is, a surface treatment of about two types of cleaning, that is, surface adjustment. As a cleaning tool, a battery-type disk sander or the like is portable and can be suitably used for small-scale surface preparation work.

The fiber sheet 1 used in this embodiment is easy to carry, and the thickness (T) of each fiber sheet 1 is 1 to 3 mm in consideration of the work time required for repair work. , length (L)×width (W) is about 300 mm×200 mm. Therefore, the surface adjustment area 104 (L104a, L104b) where the surface adjustment is performed is an area that is wider than the size (L×W) of the fiber sheet 1 to be used by the marginal length (ΔL104). The excess length of the keren is usually 5 to 50 mm, usually about 20 mm.

(Second step)
In this embodiment, unlike the first embodiment, the adhesive is not applied to the surface 104 that has been prepared, but a resin sheet adhesive 105 formed into a sheet and having weather resistance is used (Fig. 10(c)). As the weather-resistant resin sheet adhesive, one using a silicone-based resin is preferably used. As the silicone-based resin sheet adhesive 105 that can be suitably used in this embodiment, Shin-Etsu Polymer Co., Ltd.'s product name "Polymer Ace" is preferable. This silicone-based resin sheet adhesive 105 is sealed and protected, and can be maintained in an uncured state by blocking moisture. Therefore, it is a sheet-like resin that begins to harden when the seal is broken for use. When used with a primer, it exhibits good adhesion performance with steel, fiber sheets. Therefore, it is preferable to apply, for example, an epoxy-based primer (not shown) in advance to the surface-conditioned region 104 before bonding the resin sheet adhesive 105 .

As shown in FIG. 10(c), the resin sheet adhesive 105 extends not only within the range of the surface adjustment areas 104 (L104a, L104b) but also outside the range of the surface adjustment areas 104 and is removed. The size is such that it slightly overlaps the active film in the non-coated area (wrap length ΔL106). The wrap length (ΔL106) is about 20 to 100 mm, usually about 50 mm.

That is, the resin sheet adhesive 105 is bonded over the surface-conditioned region 104 and the region of the steel structure surface that is not surface-conditioned around the surface-conditioned region 104 (the region of the lap length ΔL106). .

According to the method for repairing a steel structure of the present invention, in this embodiment, as in the above embodiment, for example, as the fiber sheet 1, the reinforcing fibers f described in the above specific example 1 are aligned in one direction. Fabricated fiber sheet 1A can be used.

As shown in FIGS. 10(d) and 10(e), the fiber sheet 1A includes the damaged portion 103 of the steel structure that has undergone surface preparation, but is made to correspond to an area narrower than the entire surface-adjusted area. , is placed on the resin sheet adhesive 105 and pressed against the resin sheet adhesive 105 for adhesion. As a result, the fiber sheet 1A is bonded and integrated with the surface of the prepared steel structure having the defective portion 103 via the resin sheet adhesive 105 . At this time, the fiber sheet 1A can be impregnated with an adhesive (matrix resin) by the resin sheet adhesive 105 at the same time as the fiber sheet 1A is adhered to the steel structure. The resin impregnation amount is 30 to 70% by weight, preferably 40 to 60% by weight.

Moreover, when a large amount of reinforcement is required, it is possible to adhere a plurality of layers of the fiber sheet 1 to the surface of the structure. Usually, the fiber sheet 1 is produced by laminating two layers so as to correspond to steel of 1 mm.

Furthermore, when repairing the steel structure 100, for members (structures) that mainly receive bending moment and axial force, the orientation direction of the reinforcing fibers is generally aligned with the principal stress direction of the tensile stress or compressive stress generated by the bending moment. The fiber sheet 1 effectively bears the stress by allowing and adhering, and it is possible to efficiently improve the load-bearing capacity of the structure even with a simple repair method.

When bending moments act in two directions perpendicular to each other, two or more fiber sheets 1 are laminated and bonded so that the orientation direction of the reinforcing fibers f of the fiber sheet 1 substantially coincides with the principal stress generated by the bending moment. By doing so, the load-bearing capacity can be efficiently improved.

In the above description, the fiber sheet 1 is the resin-unimpregnated fiber sheet 1A described in Specific Example 1, but the fiber sheet 1 is a plate-shaped fiber impregnated with the resin described in Specific Example 2 and cured. It can also be a sheet, that is, an FRP plate 1B. In the case of the FRP plate 1B as well, in consideration of portability and workability, the size of the FRP plate 1B can be 300 mm x 200 mm in length (L) x width (W) as described above. In order to prevent injury and relieve stress concentration, it is preferable that the portion is rounded with a radius of about 10 mm. Generally, in the case of the FRP plate 1B, one layer has a thickness of 1 to 2 mm, which corresponds to steel of 2 to 4 mm.

As described in Example 1, according to research experiments by the present inventors, the FRP plate (CFRP plate) 1B using carbon fiber has a thickness of 0.8 mm, 1.2 mm, and 2 mm. It was found that both plates had peeling at 400 MPa (88% of the yield of steel material SM570, 1.56 times the allowable limit), and had sufficient strength for practical use. Since the CFRP plate 1B has an elastic modulus of 350 GPa, the plate thickness corresponding to a defect of 2 mm is 1.2 mm.

Further, the impregnated resin of the FRP plate 1B is hardened, and it is difficult to fit and adhere to an internal corner. Therefore, when it is necessary to repair such curved portions such as internal corners, for example, by using a thermoplastic resin as the impregnating resin for the FRP plate 1B, that is, for example, at about 80 to 100 ° C. It is made installable by using deformable field processable thermoplastics.

Furthermore, as the fiber sheet 1, a fiber sheet formed by arranging a plurality of fiber-reinforced plastic wires 2 in a threaded manner in the longitudinal direction, that is, a strand sheet 1C, as described in Example 3, may be used. In this case, the adhesive 105 is also filled in the gaps (g) between the wires 2, 2 of the strand sheet 1C, and the strand sheet 1C is adhered to the base adjustment region 104. FIG.

(Third step)
Next, as shown in FIGS. 10(e) and 10(f), the protective film described in Example 1 is attached to the surface of the steel structure, covering the fiber sheet 1 adhered to the steel structure. The protective film has weather resistance and has the function of protecting the fiber sheet 1 as described in Example 1 above. However, in this embodiment, the cured resin sheet adhesive 105 also has weather resistance. UV protection in the active film portion of the surrounding painted area (area of wrap length ΔL106) can be fully achieved with this cured resin sheet adhesive 105 . Of course, there is no problem even if the protective film 106 sheet overlaps the resin sheet adhesive 105 . Therefore, the protective film 106 can have a size larger than that of the fiber sheet 1 by ΔE, for example, 20 to 100 mm.

Incidentally, in the same manner as described in Example 1, the fiber sheet 1 used in the step (d) and the protective film 106 used in the step (e) are, as shown in FIG. 8(c), It can be pre-glued together. In this case, the step (e) can be omitted. That is, the fiber sheet 1 to which the protective film 106 has been adhered in advance can be adhered to the substrate adjustment region via the resin sheet adhesive 105 in the step (d).

According to the experimental results of the present inventors, according to the steel structure reinforcement method according to the present invention as described above, the repair material can be easily transported to the site, and the repair material can be repaired in a short period of time, such as within 10 minutes. The construction could be completed and sufficient reinforcement effect could be achieved. In addition, it is possible to easily replace the protective film 106 at the time of close visual inspection, so that sufficient reinforcement can be achieved over a long period of time.

1 fiber sheet 2 fiber reinforced plastic wire 3 wire fixing material (weft, mesh support sheet, flexible strip)
100 steel structure 102 coating (coating film)
103 Defective portion 104 Base adjustment region 105 Adhesive (silicone-based resin sheet adhesive)
106 protective film

Claims (15)

A method for repairing a steel structure by bonding and integrating a fiber sheet containing reinforcing fibers on the surface of the steel structure having a defective portion whose thickness has been reduced due to corrosion, etc.
(a) a step of surface conditioning a partial region including the defective portion on the surface of the steel structure to remove paint and rust;
(b) bonding the fiber sheet with an adhesive to a region of the conditioned steel structure that includes the defective portion but is smaller than the entire conditioned region;
(c) affixing a protective film covering the fiber sheet, the texture-conditioned area around the fiber sheet, and the non-texture-conditioned area of the structure surface;
A method for repairing a steel structure, comprising: The fiber sheet used in the step (b) and the protective film used in the step (c) are integrally bonded in advance, and the fiber sheet in the step (b) is subjected to the base adjustment. 2. The method of repairing a steel structure according to claim 1, wherein the bonding to the area and the attaching of the protective film to the peripheral area of the fiber sheet in step (c) are performed simultaneously. 3. The method of repairing a steel structure according to claim 1, wherein the adhesive used in the step (b) is a thermosetting resin or a thermoplastic resin. The thermosetting resin is a room temperature or thermosetting epoxy resin, vinyl ester resin, MMA resin, acrylic resin, unsaturated polyester resin, or phenol resin, and the thermoplastic resin is a thermoplastic epoxy resin. 4. The method of repairing a steel structure according to claim 3, wherein the material is nylon, nylon, or vinylon. A method for repairing a steel structure by bonding and integrating a fiber sheet containing reinforcing fibers on the surface of the steel structure having a defective portion whose thickness has been reduced due to corrosion, etc.
(a) a step of surface conditioning a partial region including the defective portion on the surface of the steel structure to remove paint and rust;
(b) a weather resistant sheet of silicone overlying the conditioned areas of the steel structure and areas of the steel structure surface that are not conditioned around the conditioned areas; a step of adhering a resin sheet adhesive;
(c) arranging the fiber sheet so as to correspond to an area narrower than the entire area of the steel structure that has been subjected to surface conditioning, and bonding the silicone-based resin sheet; a step of pressing and bonding the fiber sheet onto the agent;
(d) covering the fiber sheet with a protective film;
A method for repairing a steel structure, comprising: The fiber sheet used in the step (c) and the protective film used in the step (d) are integrally bonded in advance, and the step (d) is omitted. 5. The method for repairing the steel structure according to 5. The steel structure according to any one of claims 1 to 6, wherein the fiber sheet is a fiber sheet in which continuous reinforcing fibers aligned in one direction are fixed to each other with a wire fixing member. Repair method. The fiber sheet according to any one of claims 1 to 6, wherein the fiber sheet is a fiber sheet obtained by impregnating a continuous reinforcing fiber sheet aligned in one direction with a resin and curing the resin. A method of repairing a steel structure. The fiber sheet is a fiber sheet obtained by arranging a plurality of continuous fiber-reinforced plastic wires in which the reinforcing fibers are impregnated with a matrix resin and hardened, arranged in a thread shape in the longitudinal direction, and fixing the wires to each other with a wire fixing member. The method for repairing a steel structure according to any one of claims 1 to 6, characterized in that: 10. The method of repairing a steel structure according to claim 9, wherein the matrix resin is a thermosetting resin or a thermoplastic resin. The thermosetting resin is a room temperature or thermosetting epoxy resin, vinyl ester resin, MMA resin, acrylic resin, unsaturated polyester resin, or phenol resin, and the thermoplastic resin is a thermoplastic epoxy resin. 11. The method of repairing a steel structure according to claim 10, wherein the steel is , nylon, or vinylon. The method for repairing a steel structure according to any one of claims 1 to 11, wherein the fiber sheets are laminated in a plurality of layers and adhered. The reinforcing fibers include carbon fibers, glass fibers, basalt fibers; metal fibers such as boron fibers, titanium fibers, and steel fibers; The method for repairing a steel structure according to any one of claims 1 to 12, characterized in that the organic fibers are used singly or in a hybrid form by mixing a plurality of types. Claims 1 to 13, wherein the protective film has a weather-resistant acrylic resin film, vinyl chloride resin film, polycarbonate resin film, polyolefin resin film, or fluorine resin film as a base film. The method for repairing a steel structure according to any one of the items. 15. The method of repairing a steel structure according to claim 14, wherein the protective film has an adhesive layered on the base film.

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