Reinforcement method and reinforcement structure of structure

Abstract

To provide a reinforcement method and reinforcement structure that can tightly reinforce a structure made of welded steel and concrete or the like, and easily constructs the structure at a site.SOLUTION: A reinforcement method of a structure includes a first step of winding a woven fabric on the outside of the structure while applying tension thereto in a winding direction, and a second step of coating at least one of a polyurethane resin and a polyurea resin onto a surface of the woven fabric wound to the outside of the structure. Warp and weft of the woven fabric are constituted of roving or yarn. The porosity of the woven fabric has a range of 5% or more and 55% or less.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method and structure for reinforcing a structure, and more particularly to a method and structure for reinforcing a structure such as the tower section of a wind turbine tower or the pier section of a viaduct, which are made of concrete, various steel materials, etc. [Background technology]

[0002] Columnar structures such as the towers of wind turbines and the piers of viaducts are deteriorating due to rusting of the steel and reinforcing bars in welded parts and neutralization of the concrete. There have been cases of wind turbine towers collapsing before their expected service life, and there is a risk that similar incidents will occur in the future.

[0003] Various methods of reinforcing the tower section of a wind turbine tower are currently being studied. Various methods of reinforcing structures having a concrete skeleton have also been proposed. For example, Patent Document 1 proposes a method of reinforcing a concrete structure in which a fiber sheet containing reinforcing fibers is wrapped around the outer periphery of a concrete skeleton such as a bridge pier of an elevated bridge, and the outer surface of the wrapped fiber sheet is covered with a curing resin. Patent Document 2 proposes a method of reinforcing a structure in which a high-strength fiber mesh fabric is attached to a structure made of concrete blocks, and then the high-strength fiber mesh fabric is covered with a polyurea resin. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2015-34434 A [Patent Document 2] Utility Model Registration No. 3232092 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the reinforcement method proposed in Patent Document 1, the fiber sheet is not impregnated with resin, and the fiber sheet is wrapped around the outer periphery of the concrete body without being bonded to it. Therefore, there is a risk that the fiber sheet and the resin may not be sufficiently reinforced together. In addition, in the reinforcement method proposed in Patent Document 2, the void ratio of the mesh fabric is preferably 70% or more. If the void ratio of the mesh fabric is large, it is thought that the adhesion between the polyurethane resin and the structure sandwiched between the mesh fabric will improve, but the strength of the mesh fabric will decrease, and there is a risk that the structure will not be sufficiently reinforced.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a reinforcement method and structure that can more firmly reinforce structures such as the tower section of a wind turbine tower or the pier section of a viaduct, and that can be easily constructed on-site. [Means for solving the problem]

[0007] The reinforcement method of the present invention, which achieves the above-mentioned object, comprises a first step of wrapping a woven fabric around the outside of a structure while applying tension in the wrapping direction, and a second step of applying at least one of a polyurethane resin and a polyurethane resin to the surface of the woven fabric wrapped around the outside of the structure, wherein the warp and weft threads of the woven fabric are composed of roving or yarn, and the void ratio of the woven fabric is in the range of 5% to 55%.

[0008] In this specification, "roving" refers to a material made by not twisting strands of gathered fibers, and "yarn" refers to a material made by twisting strands. In the case of biaxial woven fabric, the "void ratio (%)" is calculated from the formula shown in Figure 5. In addition, the void ratio of multiaxial woven fabrics such as triaxial woven fabrics and quadriaxial woven fabrics can be determined using an image analyzer. Simply, it can be calculated by taking a black and white copy with an electrophotographic (Xerox) copier and using the copied image, (area of ​​black part / area of ​​entire effective part) x 100.

[0009] In the reinforcing method having the above configuration, in the first step, the woven fabric may be wound around the outside of the structure while applying a tension of 100 N or more to the woven fabric.

[0010] The reinforcing method as described above may further include a pretreatment step of applying an anticorrosive agent to a surface of the structure before the first step.

[0011] In the reinforcing method having the above-mentioned configuration, the first step and the second step may be configured as one set, and the set may be repeatedly performed a plurality of sets.

[0012] In the reinforcing method of the above configuration, it is preferable that the fiber constituting the roving or yarn is at least one type selected from the group consisting of carbon fiber, basalt fiber, glass fiber, aramid fiber, boron fiber, and polyparaphenylene benzobis oxazole (PBO) fiber.

[0013] The present invention also provides a reinforcement structure for a structure, characterized in that a first layer having a woven fabric in which the warp and weft threads are composed of roving or yarn and the void ratio is in the range of 5% to 55%, and a second layer having at least one of a polyurethane resin and a polyurea resin are laminated on the outside of the structure.

[0014] In the reinforcement structure having the above configuration, a rust inhibitor layer may be provided between the surface of the structure and the first layer.

[0015] In the reinforcing structure having the above configuration, it is preferable that a plurality of pairs of the first layer and the second layer are laminated.

[0016] In addition, in the reinforcing structure of the above configuration, it is preferable that the fiber constituting the roving or yarn is at least one type selected from the group consisting of carbon fiber, basalt fiber, glass fiber, aramid fiber, boron fiber, and polyparaphenylene benzobis oxazole (PBO) fiber. Effect of the Invention

[0017] According to the reinforcement method and the reinforcement structure of the present invention, construction on site can be easily carried out and a structure can be firmly reinforced. [Brief description of the drawings]

[0018] [Figure 1] 1A to 1C are process diagrams showing an example of a method for reinforcing a structure according to the present invention. [Diagram 2] FIG. 1 is a schematic diagram illustrating a method for reinforcing a structure. [Diagram 3] FIG. 1 is a schematic diagram showing an example of a device for winding a woven fabric around the outer periphery of a wind turbine tower. [Figure 4] FIG. 1 is a schematic diagram illustrating an example of a spray coating device. [Diagram 5] FIG. 2 is an explanatory diagram of the void ratio of a woven fabric. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0019] Hereinafter, the structure reinforcing method and the reinforcing structure according to the present invention will be described in detail, but the present invention is not limited to these embodiments.

[0020] FIG. 1 shows a process chart illustrating an example of a method for reinforcing a structure according to the present invention, and FIG. 2 shows a schematic diagram of the reinforcing method.

[0021] (Surface preparation) First, rust, oil, dust, and paint film are removed from the surface of the reinforcement part of the structure ST (scraping process). The scraping process is preferably type 3 or higher (type 1 scraping, type 2 scraping). In addition, if there are any weld bead protrusions on the surface of the structure ST, they are preferably removed to smooth the surface.

[0022] (Application of anti-rust agent) As shown in Fig. 2(a), a rust inhibitor is applied to the surface of a structure ST made of various steel materials, concrete, etc., with an application member such as a brush or roller to form a rust inhibitor layer 3. By providing such a rust inhibitor layer 3, the rust prevention of the structure ST is improved and the strength is also improved. In particular, when a rust inhibitor containing nanoparticles is used, if there are minute cracks in the surface layer of the structure ST, especially in the weld bead portion, the nanoparticle rust inhibitor penetrates into the cracks and hardens firmly, thereby improving the strength of the structure.

[0023] The rust inhibitor used in the present invention may be any known substance, but the "Power Rust Inhibitor NKRN-66" manufactured by SomeQ Technology Co., Ltd. is preferably used since the nanoparticles penetrate into gaps such as cracks in the structure to provide the desired strength.

[0024] There is no particular limitation on the thickness of the rust inhibitor layer 3, but in general, the thickness after drying is preferably in the range of 0.3 mm to 1.0 mm, and more preferably in the range of 0.4 mm to 0.7 mm.

[0025] (Wrapping the woven fabric (first process)) Next, as shown in FIG. 2(b), the woven fabric 4 is wrapped around the surface of the rust inhibitor layer 3. When the reinforcement portion has a welded portion, the woven fabric is wrapped around the welded portion so that the center of the entire woven fabric is aligned with the welded portion. This becomes the first layer 1. The thickness of the first layer 1 is approximately the same as the thickness of the woven fabric 4. In order for the resin applied to the woven fabric 4 to penetrate the warp threads 41 and weft threads 42 (shown in FIG. 5) of the woven fabric 4 and to penetrate the openings 43 (shown in FIG. 5) of the woven fabric 4 and to be closely attached to and integrated with the surface of the rust inhibitor layer 3, the thickness of the woven fabric 4 is preferably in the range of 0.1 mm to 1.0 mm. The thickness of the woven fabric 4 is more preferably in the range of 0.2 mm to 0.4 mm. The thickness of the woven fabric 4 can be adjusted by the thickness of the roving or yarn constituting the woven fabric 4 and the weaving structure.

[0026] The woven fabric 4 is preferably wrapped with a tension of 100 N or more in the wrapping direction. However, depending on the material of the roving or yarn constituting the woven fabric 4, applying a large tension may cause deformation of the mesh structure, so the upper limit is preferably about 200 N.

[0027] The warp threads 41 and weft threads 42 (shown in FIG. 5) of the woven fabric 4 used in the present invention are composed of roving or yarn, and the void ratio of the woven fabric 4 is preferably 5% or more and 55% or less. If the void ratio of the woven fabric 4 is less than 5%, the strength of the woven fabric 4 is obtained, but the openings 43 (shown in FIG. 5) of the woven fabric 4 are small, and the polyurethane resin or polyurea resin does not penetrate into the woven fabric 4 sufficiently, so that the woven fabric 4 and the rust inhibitor layer 3 cannot be integrated, and the desired reinforcement effect may not be obtained. On the other hand, if the void ratio of the woven fabric 4 is more than 55%, the polyurethane resin or polyurea resin penetrates into the woven fabric 4, so that the woven fabric 4 and the rust inhibitor layer 3 can be integrated, but the strength of the woven fabric 4 is insufficient and the desired reinforcement effect may not be obtained. The preferable lower limit of the void ratio of the woven fabric 4 is 6%, and the more preferable upper limit is 53%.

[0028] The gaps between the warp threads 41 and the weft threads 42 are preferably 0.4 mm or more, more preferably 0.6 mm or more. On the other hand, the upper limit of the gaps between the warp threads 41 and the weft threads 42 is preferably 1.0 mm. The area of ​​the openings 43 of the woven fabric 4 is preferably 0.16 mm or more. 2 More preferably, it is equal to or greater than this.

[0029] The fibers constituting the roving or yarn are not particularly limited, but are preferably single yarn or twisted yarn. If the fibers are untwisted yarn, the fibers are likely to become disordered or spread when the resin is sprayed onto the fibers, which may result in a decrease in the strength of the woven fabric or a change in the opening of the woven fabric. The fiber thickness is preferably 0.1 mm or less.

[0030] The fiber is preferably at least one selected from the group consisting of carbon fiber, basalt fiber, glass fiber, aramid fiber, boron fiber, and polyparaphenylene benzobis oxazole (PBO) fiber, and among these, carbon fiber and basalt fiber are more preferably used. The structure of the woven fabric is not particularly limited, but plain weave, twill weave, herringbone weave, etc. are preferred.

[0031] Fig. 3 is a schematic diagram showing an example of a device for winding the woven fabric 4 around the outer periphery of a structure (wind turbine tower) ST. The winding device 7 shown in Fig. 3 is a device that is preferably used for repairing the wind turbine tower ST. A ring-shaped work platform 52 is disposed at a predetermined height position on scaffolding 51 that has been assembled to a predetermined value so as to surround the outer periphery of the columnar wind turbine tower ST. The winding device 7 is provided on the work platform 52.

[0032] The winding device 7 has a movable guide member 71, a first clamp 72, a second clamp 73, and a spray applicator 74. The movable guide member 71 has annular upper rail member 711 and a lower rail member 712 arranged to face each other at a predetermined distance in the vertical direction. The first clamp 72, the second clamp 73, and the spray applicator 74 are provided between the upper rail member 711 and the lower rail member 712 and are guided by the upper rail member 711 and the lower rail member 712 so as to be movable in the circumferential direction of the wind turbine tower ST.

[0033] A portion of the first clamp 72 and the second clamp 73 is movable in the radial direction of the wind turbine tower ST and can come into contact with and be separated from the outer periphery of the wind turbine tower ST. Further, a portion of the first clamp 72 and the second clamp 73 can be fixed to the outer periphery of the wind turbine tower ST by a conventionally known fixing means such as a magnet.

[0034] The spray applicator 74 is disposed downstream in the movement direction from the second clamp 73. The spray applicator 74 sprays a raw material of polyurethane resin or polyurea resin onto the woven fabric 4 wrapped around the outer periphery of the wind turbine tower ST. The basic configuration of the spray applicator 74 is similar to that of the spray applicator SP shown in Fig. 4 described later, and the spray applicator 74 mixes an isocyanate compound and a polyol compound or a polyamine compound and sprays the mixture onto the wind turbine tower ST.

[0035] The woven fabric 4 is long and has a predetermined width (for example, 1 m) in the vertical direction, and is wound up in a roll and stored in the storage section of the second clamp 73 so as to be able to be unwound.

[0036] In the winding device 7 configured as above, first, the leading end of the woven fabric 4 is fixed at a predetermined position on the outer periphery of the wind turbine tower ST by the first clamp 72. Next, the second clamp 73 is guided by the upper rail member 711 and the lower rail member 712 and moves in the circumferential direction of the wind turbine tower ST, whereby the woven fabric 4 is unwound from the storage section of the second clamp 73 and wound around the outer periphery of the wind turbine tower ST. There is no particular limit to the length of the woven fabric 4 unwound per time, but it is usually about 2 m to 4 m. A predetermined tension is applied to the woven fabric 4 wound around the outer periphery of the wind turbine tower ST by applying a rotational force in the winding direction to a winding shaft (not shown) for the woven fabric built into the storage section of the second clamp 73. As described above, the tension is preferably about 100 N to 200 N.

[0037] (Application of polyurethane resin and / or polyurea resin (second step)) Next, as shown in Fig. 2(c), at least one of polyurethane resin and polyurea resin is applied to the surface of the woven fabric 4 wrapped around the structure ST. A part of the resin applied to the surface of the woven fabric 4 passes through the openings 43 of the woven fabric 4 to reach the surface of the rust inhibitor layer 3 and fill the openings 43 of the woven fabric 4. Then, a second layer 2 made of at least one of polyurethane resin and polyurea resin is formed on the surface of the woven fabric 4, resulting in a laminated structure in which the second layer 2 is formed on the outside of the first layer 1. As a result, the first layer 1 having the woven fabric 4 and the second layer 2 made of the resin are integrated together, increasing their strength.

[0038] There is no particular limitation on the thickness of the second layer 2, but it is usually preferable that the thickness is in the range of 0.5 mm to 2.0 mm. If the thickness of the second layer 2 is thinner than 0.5 mm, there is a risk that a sufficient reinforcing effect cannot be obtained. On the other hand, if the thickness of the second layer 2 is thicker than 2.0 mm, there is a risk that a sufficient effect cannot be obtained for the amount of resin used.

[0039] The polyurethane resin can be obtained by reacting a polyisocyanate compound having two or more isocyanate groups in one molecule with a polyol compound having two or more alcoholic hydroxyl groups in one molecule, while the polyurea resin can be obtained by reacting a polyisocyanate compound having two or more isocyanate groups in one molecule with a polyamine compound having an amino group.

[0040] The polyurethane resin and / or polyurea resin can be applied by a conventionally known application method such as spray application with a spray gun or roller application, but spray application with a spray gun is preferred because it reduces the labor and shortens the work time. The adhesion between the woven fabric 4 and the structure ST is improved, the strength of the reinforcing structure is increased, and workability at high places is improved.

[0041] In the case of spraying the raw material of polyurethane resin or polyurea resin, for example, a spray coating device SP shown in FIG. 4 can be used. In the spray coating device SP shown in FIG. 4, an isocyanate compound is supplied from a drum can 61, and a polyol compound or a polyamine compound is supplied from a drum can 62 to an apparatus main body 60, and the isocyanate compound and the polyol compound or the polyamine compound adjusted to a predetermined pressure in the apparatus main body 60 are supplied to a spray gun G via a heated hose 63. Then, the isocyanate compound and the polyol compound or the polyamine compound are mixed in the spray gun G and sprayed onto the structure ST. For example, the discharge pressure from the apparatus main body 60 of the spray coating device SP when spraying is about 14 MPa to 24 MPa, and the maximum liquid pressure temperature is about 90°C. For example, the "H-XP3 Reactor" manufactured by GRACO is preferably used as such a spray coating device SP.

[0042] Examples of polyisocyanate compounds include low molecular weight isocyanate compounds such as diphenylmethane-4,4'-diisocyanate (MDI), carbodiimide-modified diphenylmethane diisocyanate (liquid MDI), polymethylene polyphenylisocyanate (crude MDI), 2,4-tolylene diisocyanate (2,4-TDI), 2,6-tolylene diisocyanate (2,6-TDI), xylylene diisocyanate (XDI), hexamethylene diisocyanate, and 3-isocyanatomethyl-3,5,5-trimethylcyclohexyl isocyanate (IPDI).

[0043] Examples of the polyol compound include polyether polyol, polyester polyol, and polytetramethylene glycol.

[0044] Examples of the polyamine compound include aliphatic polyamines such as triethylenetetramine, aromatic polyamines such as metaphenylenediamine, and alicyclic polyamines such as isophoronediamine.

[0045] (resin curing) Next, as shown in FIG. 2(d), the applied resin is left to stand for several minutes to several tens of minutes after spray application to harden it.

[0046] As shown in Fig. 1, in order to increase the reinforcement of the structure, the first layer and the second layer may be alternately laminated in a plurality of layers. The first layer and the second layer can be formed by repeating the above-mentioned first and second steps. Even when the first layer and the second layer are alternately laminated in a plurality of layers, it is preferable that the outermost layer is the second layer.

[0047] In the winding device 7 of FIG. 3 described above, after the resin is sprayed from the spray applicator 74, the applied resin is left for several minutes to several tens of minutes to harden. Then, the first clamp 72 is removed from the woven fabric 4, and the resin is sprayed from the spray applicator to the attachment portion of the woven fabric 4 to which the first clamp 72 is attached, and the resin is hardened. When the sprayed resin hardens, the second clamp 73 is guided by the upper rail member 711 and the lower rail member 712 and moves again in the circumferential direction of the wind turbine tower ST, and the woven fabric 4 is unwound from the storage portion of the second clamp 73 and wound around the outer periphery of the wind turbine tower ST. Then, the spray applicator 74 sprays a raw material of polyurethane resin or polyurea resin onto the woven fabric 4 wound around the outer periphery of the wind turbine tower ST, and the resin is hardened. By repeating this operation, the first layer 1 having the woven fabric 4 and the second layer 2 made of resin are laminated and formed around the outer periphery of the wind turbine tower ST.

[0048] (Surface protective layer) 2(e), a surface protection layer 9 may be provided as the outermost layer. For such a surface protection layer 9, a fluororesin, an acrylic silicone resin, an acrylic urethane resin, an acrylic resin, or a modified resin thereof may be used. There is no particular limitation on the thickness of the surface protection layer 9, but a thickness of, for example, about 0.02 mm or more and 1.0 mm or less is preferable. EXAMPLES

[0049] Each of the woven fabrics (hereinafter referred to as "glass cloth") with different void ratios, using yarns composed of glass fibers as the warp and weft, as shown in Table 1 below, was attached to approximately half of the surface of a polyvinyl chloride pipe with a diameter of 165 mm with double-sided tape, and polyurea resin was sprayed onto the surface of the glass cloth from a position approximately 60 cm away with a spray gun. The glass cloths used were "WL230", "KQ190", "KS2750", "KS5380", and "KC0505" manufactured by Nitto Boseki Co., Ltd. 20 minutes after spray application, the glass cloth was removed from the polyvinyl chloride pipe and the back side of the glass cloth was observed using a magnifying glass to check whether the polyurea resin had penetrated the openings in the glass cloth and reached the back side.

[0050] [Table 1]

[0051] As shown in Table 1, the polyurea resin penetrated into the openings and reached the back surface of all the glass cloths examined. The larger the void ratio of the glass cloth, the greater the amount of polyurea that reached the back surface.

[0052] (others) In the above-described embodiment, the rust inhibitor layer 3 is provided, but the first layer 1 may be formed by wrapping the woven fabric 4 around the surface of the structure ST without providing the rust inhibitor layer 3, and then at least one of a polyurethane resin and a polyurea resin may be applied to form the second layer 2. Alternatively, a primer layer may be formed between the structure ST and the first layer 1 in order to increase the adhesive strength between the structure ST and the first layer 1. Alternatively, the rust inhibitor layer 3 and the primer layer may be formed. [Industrial Applicability]

[0053] According to the reinforcement method and the reinforcement structure of the present invention, construction on site can be easily carried out and a structure can be firmly reinforced. [Explanation of symbols]

[0054] 1 1st layer 2 2nd layer 3 Rust inhibitor layer 4 Woven fabric 41 Warp threads 42 Weft 43 Opening 9 Surface protective layer G Spray Gun ST structure

Claims

1. A first step of winding a woven fabric around an outer side of a structure while applying tension in a winding direction; A second step of applying at least one of a polyurethane resin and a polyurea resin to the surface of the woven fabric wrapped around the outside of the structure; having The warp and weft of the woven fabric are composed of roving or yarn, and the void ratio of the woven fabric is in the range of 5% to 55%. A method for reinforcing a structure.

2. 2. The method for reinforcing a structure according to claim 1, wherein in the first step, the woven fabric is wound around the outside of the structure by applying a tension of 100 N or more to the woven fabric.

3. 3. The method for reinforcing a structure according to claim 1, further comprising a pretreatment step of applying an anticorrosive agent to a surface of the structure prior to the first step.

4. 3. The method for reinforcing a structure according to claim 1, wherein a plurality of sets of the first step and the second step are repeatedly carried out.

5. 3. The method for reinforcing a structure according to claim 1 or 2, wherein the fiber constituting the roving or yarn is at least one type selected from the group consisting of carbon fiber, basalt fiber, glass fiber, aramid fiber, boron fiber, and polyparaphenylene benzobis oxazole (PBO) fiber.

6. A reinforcing structure for a structure, A reinforcement structure for a structure, characterized in that a first layer having a woven fabric whose warp and weft threads are composed of roving or yarn and whose void ratio is in the range of 5% to 55%, and a second layer having at least one of a polyurethane resin and a polyurea resin are laminated on the outside of the structure.

7. 7. The reinforced structure of claim 6, further comprising a rust inhibitor layer between the surface of the structure and the first layer.

8. 8. The reinforcement structure for a structure according to claim 6 or 7, wherein a plurality of pairs of the first layer and the second layer are laminated.

9. The reinforcing structure for a structure according to claim 6 or 7, wherein the fiber constituting the roving or yarn is at least one selected from the group consisting of carbon fiber, basalt fiber, glass fiber, aramid fiber, boron fiber, and polyparaphenylene benzobis oxazole (PBO) fiber.

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