Repaired structure

Abstract

To provide a repair structure capable of quickly repairing a structure.SOLUTION: A repair structure 100 includes: a base material 1 having a crack 50 and a repair hole extending so as to intersect with the crack 50; and a repair member 2 inserted into the repair hole, the repair member 2 being a laminate of a plurality of sheet pieces each having a thickness smaller than a thickness of the base material 1 and stacked on each other in a thickness direction.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to repair structures. [Background technology]

[0002] Cracks can occur in metals (e.g., steel) used in structures such as bridges and cranes due to fatigue caused by repeated loads. Various techniques have been proposed to repair such cracks. For example, Patent Document 1 discloses a structure for suppressing crack growth. In this structure, a hole is formed in a plate material having a crack so that it intersects with the crack. A member for suppressing crack growth is inserted into this hole. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-199846 Summary of the Invention [Problem to be solved by the invention]

[0004] In Patent Document 1, the components to be inserted into the plate material may be prepared in advance by predicting the shape, dimensions, and thickness of the holes to be formed in the plate material at the repair site. However, there is a possibility that the components prepared in advance and the holes to be formed at the repair site may not match each other. In this case, additional time is required to correct the components (or holes) to be inserted into the plate material, making it impossible to repair the structure quickly.

[0005] In consideration of the above-mentioned problems, the present disclosure aims to provide a repair structure that can quickly repair a structure. [Means for solving the problem]

[0006] In order to solve the above problem, a repair structure according to one aspect of the present disclosure includes a base material having a crack and a repair hole extending so as to intersect with the crack, and repair members inserted into the repair hole, each of the repair members having a thickness smaller than that of the base material; Base material It is a laminate of multiple sheet pieces stacked on top of each other in the thickness direction. The plurality of sheet pieces are stacked on top of each other in the thickness direction of the sheet pieces. , and a repair member.

[0007] The sheet pieces may be made of carbon fiber reinforced plastic.

[0008] The repair component may include carbon fibers extending in multiple directions.

[0009] Another aspect of the present disclosure is a repair method, comprising the steps of: forming a repair hole in a base material having a crack, the repair hole extending to intersect with the crack; forming a plurality of sheet pieces having a shape corresponding to the repair hole from a sheet having a thickness smaller than that of the base material; and joining the plurality of sheet pieces to the repair hole. , of the base material forming a repair member laminated in the thickness direction in the repair hole. The plurality of sheet pieces are stacked on top of each other in the thickness direction of the sheet pieces. .

[0010] The step of forming the repair member in the repair hole includes: Sheet piece This may include laminating in the thickness direction and then fitting into the repair hole. [Effects of the Invention]

[0011] According to the present disclosure, it is possible to provide a repair structure that can quickly repair a structure. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a plan view showing a repair structure according to a first embodiment. [Figure 2] FIG. 2 is a plan view showing the base material of FIG. 1 before the repair member is inserted. [Figure 3] FIG. 3 is a schematic perspective view showing a method for producing a repair member. [Figure 4] FIG. 4 is a schematic plan view showing a method for cutting sheet pieces from a sheet. [Figure 5] FIG. 5 is a plan view showing the repair structure according to the second embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. Specific dimensions, materials, numerical values, etc. shown in the embodiments are merely examples for ease of understanding and do not limit the present disclosure unless otherwise specified. In this specification and drawings, elements having substantially the same functions and configurations are designated by the same reference numerals to avoid redundant description. Elements not directly related to the present disclosure are not shown.

[0014] [First embodiment] 1 is a plan view showing a repair structure 100 according to a first embodiment. The repair structure 100 is applied to an existing structure (e.g., a bridge or a crane) having a crack 50. The repair structure 100 comprises a base material 1 and a plurality of (four in this embodiment) repair members 2. The number of repair members 2 can be determined depending on various factors such as the size of the crack 50, and may be, for example, three or less or five or more.

[0015] The base material 1 can be part of a structure and is made of metal (e.g., steel). The base material 1 is, for example, plate-shaped. The thickness of the base material 1 is, for example, about 6 mm or more and 8 mm or less. The thickness of the base material 1 is not limited to this and may be less than 6 mm or more than 8 mm. The base material 1 has a crack 50.

[0016] The crack 50 may occur, for example, due to fatigue caused by repeated loads applied to the structure. In this embodiment, the crack 50 has a linear shape. The shape of the crack 50 is not limited to this, and may have other shapes in other embodiments. Note that in FIG. 1, the thickness of the crack 50 (the length in the vertical direction in FIG. 1) is exaggerated for better understanding. In an actual structure, the crack 50 may be thinner.

[0017] The crack 50 has an end 51 on the surface 11 of the base material 1. In this embodiment, the entire crack 50 is located within the surface 11 of the base material 1. Therefore, in this embodiment, the crack 50 has two ends 51 within the surface 11 of the base material 1. In other embodiments, the crack 50 may reach the edge 12 of the base material 1. In this case, the end 51 of the crack 50 is located on the edge 12.

[0018] 2 is a plan view showing the base material 1 of FIG. 1 before the repair member 2 is inserted. The base material 1 has a plurality of repair holes 13 (four in this embodiment). The repair holes 13 are formed, for example, near the end portion 51 in order to suppress the growth of the crack 50. The repair holes 13 extend so as to intersect with the crack 50. For example, the repair holes 13 are formed in the base material 1 so as to be symmetrical with respect to the crack 50 (or the central axis of the crack 50).

[0019] The repair hole 13 has a central axis 13a that extends to intersect with the crack 50. In this embodiment, the central axis 13a has a linear shape. In this embodiment, the repair hole 13 is symmetrical about the central axis 13a. The central axis 13a is perpendicular (or approximately perpendicular) to the crack 50 (or the central axis of the crack 50). The width of the repair hole 13 (the length perpendicular to the central axis 13a) is greatest near both ends of the central axis 13a. For example, the repair hole 13 can be formed by a curve to reduce stress concentration. In other embodiments, the repair hole 13 may include a straight portion as long as a large stress concentration does not occur.

[0020] Referring to FIG. 1 , the repair member 2 has a shape that roughly corresponds to the repair hole 13 and is inserted into the repair hole 13. For example, the repair member 2 is slightly smaller than the repair hole 13 so that a worker can fit the repair member 2 into the repair hole 13 by hand or using a tool. For example, the gap between the repair member 2 and the repair hole 13 may be filled with an adhesive (not shown). Note that the shape of the repair member 2 does not have to completely correspond to the repair hole 13; for example, the outline of part of the repair member 2 may be different from the outline of the repair hole 13. As described below, the repair member 2 is formed, for example, from carbon fiber reinforced plastic. For example, the thickness of the repair member 2 is equal to or greater than the thickness of the base material 1.

[0021] For example, the shapes of the repair hole 13 and the repair member 2 may be determined by experiment or analysis using a test piece simulating the crack 50. For example, the stress intensity factor range ΔK is calculated based on the strain at the end 51 of the crack 50. The shapes, number, and spacing of the repair holes 13 and the repair member 2 may be calculated so that this stress intensity factor range ΔK is equal to or less than the threshold stress intensity factor range ΔKth. The threshold stress intensity factor range ΔKth is determined by factors such as the material of the base material 1 and the dimensions of the crack 50.

[0022] FIG. 3 is a schematic perspective view showing a method for producing the repair member 2. The repair member 2 is a laminate of multiple (six in FIG. 3) sheet pieces 21. The number of sheet pieces 21 is not limited to this and may be, for example, five or less or seven or more depending on the thickness of the base material 1. The sheet pieces 21 have a thickness smaller than that of the base material 1 (for example, 1 mm or less). The thickness of the sheet pieces 21 is not limited to this and may be more than 1 mm. The multiple sheet pieces 21 are stacked on top of each other in the thickness direction. The multiple sheet pieces 21 may be attached to each other, for example, by an adhesive.

[0023] In this embodiment, the sheet pieces 21 are made of carbon fiber reinforced plastic. The repair member 2 includes carbon fibers (not shown) extending in multiple directions. For example, the repair member 2 may include carbon fibers extending at least in the extension direction of the repair member 2 (left-right direction in FIG. 3) (i.e., a direction perpendicular to the crack 50). For example, each of the multiple sheet pieces 21 may include carbon fibers extending in a single direction, or the extension directions of the carbon fibers of the multiple sheet pieces 21 may be different from one another. Alternatively, each of the multiple sheet pieces 21 may include carbon fibers extending in multiple directions.

[0024] Next, a method for applying the repair structure 100 to a structure will be described.

[0025] 2, a repair hole 13 is formed in a base material 1 of a structure in which a crack 50 is found. For example, first, an incision is formed in the base material 1 with a cutter, and then the repair hole 13 may be formed by electrical discharge machining. For example, the repair hole 13 may be formed in a predetermined shape.

[0026] FIG. 4 is a schematic plan view showing a method for cutting sheet pieces 21 from a sheet 90. Next, multiple sheet pieces 21 are prepared according to the shape of the repair hole 13. For example, multiple sheet pieces 21 may be cut from a single sheet 90. If one sheet 90 is not enough, sheet pieces 21 may be cut from multiple sheets 90. The sheet pieces 21 may be cut from the sheet 90 by a worker at the repair site using a cutting tool such as scissors or a cutter. For example, if the sheet 90 is a carbon fiber reinforced plastic containing carbon fibers extending in multiple directions (e.g., a sheet in which multiple sheets of carbon fiber reinforced plastic containing carbon fibers extending in a single direction are already stacked), multiple sheet pieces 21 may be cut from the sheet 90 in the same direction as shown in FIG. 4. Alternatively, for example, if the sheet 90 is a carbon fiber reinforced plastic containing only carbon fibers extending in a single direction, multiple sheet pieces 21 may be cut from the sheet 90 in different directions (not shown).

[0027] Referring to FIG. 3, next, a plurality of sheet pieces 21 are stacked in the thickness direction to prepare the repair member 2.

[0028] 1, next, a repair member 2 is fitted into the repair hole 13, and the gap between the repair hole 13 and the repair member 2 is filled with adhesive. Note that a plurality of sheet pieces 21 may be stacked and then fitted into the repair hole 13, or a plurality of sheet pieces 21 may be sequentially fitted into the repair hole 13. In other words, any method may be used as long as a repair member 2 in which a plurality of sheet pieces 21 are stacked is formed inside the repair hole 13.

[0029] When a load is applied to the above-described repair structure 100, the repair member 2 receives the load. Therefore, the crack 50 can be prevented from opening, and the crack 50 can be prevented from propagating from the end 51.

[0030] The repair structure 100 described above includes a base material 1 having a crack 50 and a repair hole 13 extending to intersect with the crack 50, and a repair member 2 inserted into the repair hole 13. The repair member 2 is a laminate of multiple sheet pieces 21, each having a thickness smaller than that of the base material 1, stacked on top of each other in the thickness direction. A repair method for applying such repair structure 100 to a structure includes the steps of: forming a repair hole 13 in the base material 1 having the crack 50, the repair hole 13 extending to intersect with the crack 50; forming multiple sheet pieces 21 in a shape corresponding to the repair hole 13 from a sheet 90 having a thickness smaller than that of the base material 1; and fitting the multiple sheet pieces 21 to the repair hole 13 to form a repair member 2 in the repair hole 13, in which the multiple sheet pieces 21 are stacked in the thickness direction. As described above, the sheet pieces 21 of the repair member 2 used in such repair structure 100 and repair method can be easily cut out from the sheet 90 by workers at the repair site using a cutting tool such as scissors or a cutter. Therefore, the repair member 2 can be quickly prepared at the repair site. Therefore, the structure can be quickly repaired.

[0031] Furthermore, in the repair structure 100, the sheet piece 21 is formed of carbon fiber reinforced plastic. Therefore, the repair member 2 formed from the sheet piece 21 is lightweight and has high strength.

[0032] Furthermore, in the repair structure 100, the repair member 2 includes carbon fibers that extend in multiple directions, and therefore the repair member 2 has resistance to loads from various directions.

[0033] The process of forming the repair member 2 in the repair hole 13 may also include stacking a plurality of sheet pieces 21 in the thickness direction and then fitting them into the repair hole 13. In this case, for example, the thickness of the repair member 2 can be confirmed before fitting the repair member 2 into the repair hole 13.

[0034] [Second embodiment] 5 is a plan view showing a repair structure 200 according to a second embodiment. The repair structure 200 according to the second embodiment differs from the repair structure 100 according to the first embodiment in that the repair structure 200 includes a repair plate 7 and a bolt 8. Other points may be the same as those of the repair structure 100 described above. Therefore, a description of other points will be omitted.

[0035] The repair plate 7 is plate-shaped. The repair plate 7 has a size that can cover the entire crack 50, for example. In this embodiment, the repair plate 7 is rectangular. However, the shape of the repair plate 7 is not limited thereto and can be modified, for example, depending on the shape of the crack 50. The thickness of the repair plate 7 is, for example, the same as the thickness of the base material 1. Alternatively, the thickness of the repair plate 7 may be smaller or larger than the thickness of the base material 1. The repair plate 7 may be formed, for example, from the same material as the base material 1, the same material as the repair member 2, or a different material from the base material 1 and the repair member 2. The repair plate 7 may be attached to the base material 1, for example, by an adhesive.

[0036] The repair plate 7 has a through hole that corresponds to the shape of the repair member 2. Therefore, in this embodiment, the repair member 2 is fitted into both the base material 1 and the repair plate 7. Gaps between the repair member 2 and the base material 1 and between the repair member 2 and the repair plate 7 may be filled with adhesive.

[0037] In this embodiment, a through hole (a so-called stop hole) is formed in the base material 1 at the end 51 of the crack 50. A bolt 8 is passed through this through hole. Similarly, the repair plate 7 has a through hole at a position corresponding to the through hole in the base material 1. The bolt head of the bolt 8 is located in this through hole. The bolt 8 fastens the base material 1. In other embodiments, the bolt head of the bolt 8 may be located on the repair plate 7, and the bolt 8 may fasten the base material 1 and the repair plate 7 together. The bolt 8 may be, for example, a high-strength bolt or a one-sight bolt.

[0038] The repair structure 200 as described above has the same effects as the repair structure 100 according to the first embodiment.

[0039] In particular, the repair structure 200 further includes a repair plate 7. Therefore, the repair plate 7 can further suppress the propagation of the crack 50.

[0040] Moreover, the repair structure 200 further includes a bolt 8 that is passed through the stop hole. Therefore, the stop hole and the bolt 8 can further suppress the propagation of the crack 50 from the end 51.

[0041] Although the embodiments have been described above with reference to the accompanying drawings, the present disclosure is not limited to the above-described embodiments. It is clear that a person skilled in the art can conceive of various modifications or alterations within the scope of the claims, and it is understood that such modifications also fall within the technical scope of the present disclosure.

[0042] For example, in the above embodiment, the sheet piece 21 is made of carbon fiber reinforced plastic. However, in other embodiments, the sheet piece 21 may be made of another material (for example, metal (for example, steel)) as long as the sheet piece 21 can be cut out by a worker at the repair site using a cutting tool such as scissors or a cutter.

[0043] In the above-described embodiments, the repair structures 100, 200 are applied to a crack 50 that has occurred in the plate-shaped base material 1. However, in other embodiments, the repair structures 100, 200 may be applied to a crack that has occurred in a joint between multiple plate-shaped base materials that are joined at a right angle or a predetermined angle. In this case, for example, the repair member 2 may be configured to be fitted across the multiple base materials.

[0044] This disclosure can promote the rapid repair of structures, thereby contributing to Goal 9 of the United Nations-led Sustainable Development Goals (SDGs), which is to "Build resilient infrastructure, promote sustainable industrialization and foster innovation," and Goal 11, which is to "Make cities inclusive, safe, resilient and sustainable." [Explanation of symbols]

[0045] 1 Base material 2 Repair materials 13 Repair hole 21 Sheet pieces 50 Crack 100 Repaired Structure 200 Repaired Structure

Claims

1. A base material having a crack and a repair hole extending to intersect with the crack; a repair member to be inserted into the repair hole, the repair member being a laminate of a plurality of sheet pieces each having a thickness smaller than the thickness of the base material and stacked on top of each other in the thickness direction of the base material, the plurality of sheet pieces being stacked on top of each other in the thickness direction of the sheet pieces; Equipped with Repair structure.

2. The repair structure according to claim 1 , wherein the sheet piece is formed of carbon fiber reinforced plastic.

3. The repair structure according to claim 2 , wherein the repair member includes carbon fibers extending in multiple directions.

4. forming a repair hole in a base material having a crack, the repair hole extending across the crack; forming a plurality of sheet pieces having shapes corresponding to the repair holes from a sheet having a thickness smaller than that of the base material; a step of fitting the plurality of sheet pieces into the repair hole to form a repair member in the repair hole in which the plurality of sheet pieces are stacked in a thickness direction of the base material; Including, The plurality of sheet pieces are stacked on top of each other in the thickness direction of the sheet pieces. Repair method.

5. The repair method according to claim 4, wherein the step of forming the repair member in the repair hole includes stacking the plurality of sheet pieces in a thickness direction of the sheet pieces and then fitting the sheet pieces into the repair hole.

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