Repair structure

Abstract

To provide a repair structure which has higher resistance against tensile forces.SOLUTION: A repair structure 100 includes a base material 1 which has a crack 50 and a repair hole extending to intersect the crack 50, and a repair member 2 which is inserted into the repair hole and has a first side 2d and a second side 2e extending to intersect the crack 50. The first side 2d is closer to the end 51 of the crack 50 than the second side 2e. The repair member 2 includes a central axis 2a. Regarding the central axis 2a, the intersection part 2b between the central axis 2a and the crack 50 curves away from the end 51 of the crack 50 in the extension direction of the crack 50 at the intersection 2b, compared to both ends 2c of the central axis 2a, and the first side 2d curves in the same direction as the center axis 2a.SELECTED DRAWING: Figure 1

Description

[Technical field]

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

[0002] Metals (e.g., steel) used in structures such as bridges or cranes can develop cracks 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 the growth of a crack. In this structure, a hole is formed in a plate material having a crack so as to intersect with the crack. A member for suppressing the growth of the crack is inserted into this hole. The longitudinal direction of this member is in a direction intersecting with the crack. Both longitudinal ends have a width greater than that of the center. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-199846 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned crack repair structure, various loads such as bending force and tensile force are applied to the crack. Therefore, it is desirable for such a repair structure to have higher resistance to the various loads.

[0005] In consideration of the above-mentioned problems, the present disclosure has an object to provide a repair structure that has higher resistance to loads applied to a crack, particularly tensile force. [Means for solving the problem]

[0006] In order to solve the above problems, a repair structure according to one embodiment of the present disclosure comprises: a base material having a crack and a repair hole extending to intersect with the crack; and a repair member inserted into the repair hole, the repair member having a first side and a second side extending to intersect with the crack and positioned opposite each other, wherein the first side is closer to an end of the crack than the second side, the repair member including a central axis formed by connecting the midpoints of two points on the first side and the second side, the central axis being located between the first side and the second side such that a vertical distance from the crack at a point on the first side is equal to a vertical distance from the crack at a point on the second side, the central axis being curved such that an intersection between the central axis and the crack is curved away from the end of the crack compared to both ends of the central axis in the extension direction of the crack at the intersection, and the first side is curved in the same direction as the central axis.

[0007] The second side may also be curved in the same direction as the central axis.

[0008] The second side may be curved away from the central axis with a curvature that is less than the curvature of the first side.

[0009] A repair structure according to another aspect of the present disclosure comprises a base material having a crack and a repair hole extending to intersect with the crack, and a repair member inserted into the repair hole and having a first side and a second side extending to intersect with the crack and located opposite each other, wherein a point projected onto the extension line of the crack of the first half of the repair member, which is the area center of gravity of the first half in a plane parallel to the surface of the base material in which the repair hole is formed, is closer to the end of the crack in the direction of extension of the crack than a midpoint between the intersection of the crack and the first side and the intersection of the crack and the second side, and a point projected onto the extension line of the second half of the repair member, which is the area center of gravity of the second half in a plane parallel to the surface of the base material in which the repair hole is formed, is closer to the end of the crack in the direction of extension of the crack than the midpoint. Effect of the Invention

[0010] According to the present disclosure, it is possible to provide a repair structure that is more resistant to tensile forces. [Brief description of the drawings]

[0011] [Figure 1] FIG. 1 is a plan view showing a repair structure according to a first embodiment. [Diagram 2] FIG. 2 is a plan view showing the base material of FIG. 1 before the repair member is inserted. [Diagram 3] FIG. 3 is a plan view showing the repair structure according to the second embodiment. [Figure 4] FIG. 4 is a plan view showing a repair structure according to a comparative example. [Diagram 5] FIG. 5 is a plan view showing a repair structure according to the third embodiment. [Figure 6] FIG. 6 is a plan view showing a repair structure according to the fourth embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Hereinafter, the embodiments of the present disclosure will be described in detail with reference to the accompanying drawings. The 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 given the same reference numerals to avoid repeated explanation. In addition, elements not directly related to the present disclosure are not illustrated.

[0013] [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 repair members 2 (four in this embodiment). 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.

[0014] The base material 1 can be a part of a structure and is made of metal (for example, steel). The base material 1 has, for example, a plate shape. The base material 1 has a crack 50.

[0015] The crack 50 may be generated, for example, by fatigue caused by repeated loads applied to the structure. In this embodiment, the crack 50 has a linear shape. However, the shape of the crack 50 is not limited thereto, and may be 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.

[0016] 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. Thus, in this embodiment, the crack 50 has two ends 51 within the surface 11 of the base material 1. However, 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.

[0017] 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 near the end 51 to suppress the growth of a crack 50 from the end 51. In the following description of the repair holes 13 and the repair member 2, the "end 51" may mean the one closest to the repair holes 13 and the repair member 2.

[0018] The repair hole 13 extends so as to intersect with the crack 50. For example, the repair hole 13 is formed in the base material 1 so as to be line-symmetric with respect to the crack 50 (or the central axis of the crack 50). In this embodiment, the repair hole 13 has a roughly boomerang shape.

[0019] The repair hole 13 has a first side 13d and a second side 13e. Each of the first side 13d and the second side 13e extends so as to intersect the crack 50. The first side 13d and the second side 13e are opposite to each other. The first side 13d is closer to the end 51 than the second side 13e. The repair hole 13 has a central axis 13a. The central axis 13a is between the first side 13d and the second side 13e, and is formed by connecting the midpoints of two points on each side, which are located such that the vertical distance from the crack 50 to a point on the first side 13d and the vertical distance from the crack 50 to a point on the second side 13e are both equal. The width of the repair hole 13 (the distance between the first side 13d and the second side 13e) is greatest near both ends 13c of the central axis 13a.

[0020] The central axis 13a is curved such that the intersection 13b between the central axis 13a and the crack 50 is farther away from the end 51 of the crack 50 than both ends 13c of the central axis 13a in the extension direction of the crack 50 at the intersection 13b (left and right direction in FIG. 2). From another perspective, the central axis 13a is curved such that the intersection 13b between the central axis 13a and the crack 50 is located on the opposite side of the end 51 with respect to the line connecting both ends 13c of the central axis 13a. From yet another perspective, the center of curvature of the central axis 13a at the intersection 13b of this embodiment is located on the end 51 side with respect to the line connecting both ends 13c of the central axis 13a. In this embodiment, both the first side 13d and the second side 13e are curved in the same direction as the central axis 13a.

[0021] For example, the repair hole 13 can be formed with a curved line to reduce stress concentrations, however, in other embodiments, the repair hole 13 may include straight lines as long as they do not cause significant stress concentrations.

[0022] 1, the repair member 2 has a shape that generally 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 by 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, and for example, the outline of a part of the repair member 2 may be different from the outline of the repair hole 13.

[0023] As described above, in this embodiment, the repair member 2 has a shape corresponding to the repair hole 13. Specifically, the repair member 2 extends so as to intersect with the crack 50. For example, the repair member 2 is line-symmetric with respect to the crack 50 (or the central axis of the crack 50). In this embodiment, the repair member 2 has a roughly boomerang shape.

[0024] The repair member 2 has a first side 2d and a second side 2e. Each of the first side 2d and the second side 2e extends so as to intersect the crack 50. The first side 2d and the second side 2e are opposite to each other. The first side 2d is closer to the end 51 than the second side 2e. The repair member 2 has a central axis 2a. The central axis 2a is between the first side 2d and the second side 2e, and is a line connecting the midpoints of two points on each side, which are taken so that the vertical distance from the crack 50 to a point on the first side 2d and the vertical distance from the crack 50 to a point on the second side 2e are both equal. The width of the repair member 2 (the distance between the first side 2d and the second side 2e) is largest near both ends 2c of the central axis 2a.

[0025] The central axis 2a is curved such that the intersection 2b between the central axis 2a and the crack 50 is farther away from the end 51 of the crack 50 than both ends 2c of the central axis 2a in the extension direction of the crack 50 at the intersection 2b (left and right direction in FIG. 1). From another perspective, the central axis 2a is curved such that the intersection 2b between the central axis 2a and the crack 50 is located on the opposite side of the end 51 with respect to the line connecting both ends 2c of the central axis 2a. From yet another perspective, the center of curvature of the central axis 2a at the intersection 2b of this embodiment is located on the end 51 side with respect to the line connecting both ends 2c of the central axis 2a. In this embodiment, both the first side 2d and the second side 2e are curved in the same direction as the central axis 2a. From another perspective, the first side 2d is curved so as to be recessed toward the outside of the repair member 2, while the second side 2e is curved so as to be protruded toward the outside of the repair member 2.

[0026] For example, the repair member 2 can be formed with curves to reduce stress concentrations, however, in other embodiments, the repair member 2 may include straight sections as long as no significant stress concentrations are generated.

[0027] The repair member 2 is formed of, for example, a metal (for example, high-strength steel (high-tensile steel)) having a higher strength than the base material 1. For example, the thickness of the repair member 2 is equal to or greater than the thickness of the base material 1.

[0028] 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, a stress intensity factor width ΔK is calculated based on the strain at the end 51 of the crack 50. The shapes of the repair hole 13 and the repair member 2, their number, and the spacing between them may be calculated so that this stress intensity factor width ΔK is equal to or smaller than the threshold stress intensity factor width ΔKth. The threshold stress intensity factor width ΔKth is determined by factors such as the material of the base material 1 and the dimensions of the crack 50.

[0029] Next, a method for applying the repair structure 100 to a structure will be described.

[0030] 2, a repair hole 13 is formed in a base material 1 of a structure in which a crack 50 is found. For example, a cutter may first be used to form a notch in the base material 1, and then the repair hole 13 may be formed by electric discharge machining. For example, the repair hole 13 may be formed according to the shape of a repair member 2 prepared in advance. Alternatively or additionally, the repair member 2 may be created or modified at the repair site according to the shape of the repair hole 13 formed in the base material 1.

[0031] Referring to FIG. 1, next, repair member 2 is fitted into repair hole 13, and the gap between repair hole 13 and repair member 2 is filled with adhesive.

[0032] Next, a case where a tensile force is applied to the repair structure 100 will be described.

[0033] FIG. 4 is a plan view showing a repair structure 500 according to a comparative example. The repair structure 500 includes a repair member 9 instead of the above-mentioned repair member 2. As shown in FIG. 4, in the repair member 9, the central axis 9a is a straight line, and the first side 9d and the second side 9e are symmetrical with respect to the central axis 9a. The repair member 9 has a larger width near both ends of the central axis 9a. As shown in FIG. 4, when a tensile force T0 perpendicular to the extension direction of the crack 50 is applied to the repair structure 500, a tensile stress T1 perpendicular to the extension direction of the crack 50 is applied to the end 51 of the crack 50. Such a tensile stress T1 is received by the portion of the repair member 9 that intersects with the direction of the tensile stress T1 (i.e., the wide portion near both ends of the central axis 9a).

[0034] Symmetrically, referring to FIG. 1, in the repair member 2 of the present disclosure, the central axis 2a is curved so that the intersection 2b between the central axis 2a and the crack 50 is farther from the end 51 of the crack 50 than both ends 2c of the central axis 2a in the extension direction of the crack 50 at the intersection 2b, and the first side 2d close to the end 51 is curved in the same direction as the central axis 2a. In such a repair member 2, more parts of the first side 2d (parts near both ends) intersect with the direction perpendicular to the extension direction of the crack 50 (i.e., the direction of the tensile stress T1). Therefore, more parts of the first side 2d can receive the tensile stress T1. In addition, the second side 2e receives a reaction force of the tensile stress T1. This second side 2e is also curved in the same direction as the central axis 2a. That is, the second side 2e is curved so as to protrude. Therefore, the second side 2e can suppress stress concentration. Therefore, the repair structure 100 of the present disclosure can improve resistance to the tensile force T0 compared to the repair structure 500 according to the comparative example.

[0035] As described above, the repair structure 100 of the present disclosure comprises 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 and having a first side 2d and a second side 2e that extend to intersect with the crack 50 and are located opposite each other. The first side 2d is closer to the end 51 of the crack 50 than the second side 2e, and the repair member 2 is between the first side 2d and the second side 2e, and includes a central axis 2a formed by connecting the midpoints of two points on the first side 2d and the second side 2e, which are taken so that the vertical distance from the crack 50 to the point on the first side 2d is equal to the vertical distance from the crack 50 to the point on the second side 2e, and the central axis 2a is curved so that the intersection 2b between the central axis 2a and the crack 50 is away from the end 51 of the crack 50 compared to both ends 2c of the central axis 2a in the extension direction of the crack 50 at the intersection 2b, and the first side 2d is curved in the same direction as the central axis 2a. With this configuration, as described above, a larger portion of the first side 2d intersects with the direction of the tensile stress T1. Therefore, the first side 2d can bear the tensile stress T1 securely. Therefore, the repair structure 100 has higher resistance to the tensile force T0 perpendicular to the extension direction of the crack 50.

[0036] In addition, in the repair structure 100, the second side 2e is also curved in the same direction as the central axis 2a. With this configuration, the second side 2e that receives the reaction force of the tensile stress T1 is curved so as to protrude. Therefore, the center part B of the second side 2e can suppress stress concentration.

[0037] [Second embodiment] 3 is a plan view showing a repair structure 200 according to the 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 shape of the repair member 3 (and the shape of the repair hole) is different from the shape of the repair member 2 according to the first embodiment. Other points may be the same as those of the above-mentioned repair structure 100. Therefore, a description of the other points will be omitted. Also, as described above, the shape of the repair hole corresponds to the shape of the repair member 3. Therefore, a description of the repair hole will also be omitted.

[0038] In the repair member 3 according to the second embodiment, the second side 3e is curved in the opposite direction to the central axis 3a. Specifically, the second side 3e is curved in the opposite direction to the central axis 3a with a curvature smaller than that of the first side 3d. From another perspective, the second side 3e is curved so as to be concave when viewed from the outside of the repair member 3.

[0039] The repair structure 200 as described above has the same effects as the repair structure 100 according to the first embodiment.

[0040] In particular, in the repair structure 200, the second side 3e of the repair member 3 is curved in the opposite direction to the central axis 3a with a curvature smaller than that of the first side 3d. Since the curvature of the second side 3e is smaller than that of the first side 3d, even in such a repair structure 200, the second side 3e can suppress stress concentration when it receives a reaction force of the tensile stress T1. Moreover, in such a repair member 3, the width of the repair member 3 is larger near both ends 3c of the central axis 3a than in the repair member 2 according to the first embodiment. Therefore, the strength of the repair member 3 near both ends 3c can be improved.

[0041] [Third embodiment] 5 is a plan view showing a repair structure 300 according to a third embodiment. The repair structure 300 according to the third embodiment differs from the repair structure 100 according to the first embodiment in that the repair structure 300 includes a repair plate 7 and a bolt 8. Other points may be the same as those of the above-mentioned repair structure 100. Therefore, a description of the other points will be omitted.

[0042] 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, according to 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, of the same material as the base material 1, the same material as the repair member 2, or a material different from the base material 1 and the repair member 2. The repair plate 7 may be attached to the base material 1 by, for example, an adhesive.

[0043] The repair plate 7 has a through hole corresponding 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 plate 7 and the repair member 2 may be filled with adhesive.

[0044] In this embodiment, a through hole is formed in the base material 1 at the end 51 of the crack 50 (a so-called stop hole). 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-site bolt.

[0045] The repair structure 300 as described above provides the same effects as the repair structure 100 according to the first embodiment.

[0046] In particular, the repair structure 300 further includes a repair plate 7. Therefore, the repair plate 7 can further suppress the growth of the crack 50.

[0047] Moreover, the repair structure 300 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 portion 51.

[0048] [Fourth embodiment] FIG. 6 is a plan view showing a repair structure 400 according to the fourth embodiment. The repair structure 400 according to the fourth embodiment differs from the repair structure 100 according to the first embodiment in that the shape of the repair member 4 (and the shape of the repair hole) is different from the shape of the repair member 2 according to the first embodiment. Other points may be the same as those of the repair structure 100 described above. Therefore, a description of other points will be omitted. Also, as described above, the shape of the repair hole corresponds to the shape of the repair member 4. Therefore, a description of the repair hole will also be omitted. In the repair member 4 according to the fourth embodiment, the first side 4d is curved so as to be more recessed toward the outside of the repair member 4.

[0049] The repair structure 400 as described above provides the same effects as the repair structure 100 according to the first embodiment.

[0050] Also, from another perspective, the repair member 4 according to the fourth embodiment includes an upper half (first half) 41 and a lower half (second half) 42. In this disclosure, the terms "upper" and "lower" refer to "upper" and "lower" in the drawings, respectively, and may not refer to a specific direction of a specific element. The upper half 41 and the lower half 42 are located opposite each other across the crack 50.

[0051] The upper half 41 includes a first area center of gravity (first half area center of gravity) 41a. The first area center of gravity 41a is the area center of gravity of the upper half 41 in a plane parallel to the surface 11 where the repair hole 13 of the base material 1 is formed. A point 41b (hereinafter, may also be referred to as a projection point) obtained by projecting the first area center of gravity 41a onto the extension line L of the crack 50 is closer to the end 51 of the crack 50 in the extension direction of the crack 50 than a midpoint 43 between the intersection point of the crack 50 and the first side 4d and the intersection point of the crack 50 and the second side 4e. The extension line L of the crack 50 is a straight line connecting the intersection point of the crack and the first side 4d of the repair hole 13 and the intersection point of the crack and the second side 4e of the repair hole 13.

[0052] The lower half 42 includes a second area center of gravity (second half area center of gravity) 42a. The second area center of gravity 42a is the area center of gravity of the lower half 42 in a plane parallel to the surface 11. A point 42b (which may hereinafter also be referred to as a projection point) obtained by projecting the second area center of gravity 42a onto the extension line L is located closer to the end 51 of the crack 50 in the extension direction of the crack 50 than the midpoint 43. Note that in this embodiment, the projection point 42b is located at the same point as the projection point 41b, but in other embodiments, they may be located at different points.

[0053] The repair structure 400 as 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 4 inserted into the repair hole 13 and having a first side 4d and a second side 4e extending to intersect with the crack 50 and positioned on opposite sides. The point 41b is closer to the end 51 of the crack 50 in the extension direction of the crack 50 than the midpoint 43 between the intersection of the crack 50 and the first side 4d and the intersection of the crack 50 and the second side 4e, and the projection point 42b of the second area center of gravity 42a of the lower half 42 of the repair member 4 across the extension line L of the crack 50 is closer to the end 51 of the crack 50 in the extension direction of the crack 50 than the midpoint 43. Even when viewed from this perspective, in the repair structure 400, a larger portion of the first side 4d intersects with the direction of the tensile stress T1. Therefore, the first side 4d can firmly receive the tensile stress T1. Therefore, the repair structure 400 has a higher resistance to the tensile force T0 perpendicular to the extension direction of the crack 50.

[0054] In the above description of the repair structure 100 according to the first embodiment, the repair structure 200 according to the second embodiment, and the repair structure 300 according to the third embodiment, the first area center of gravity of the upper half portion, the first area center of gravity of the lower half portion, the projection point, and the midpoint are not mentioned, but it should be noted that the above relationship between the first area center of gravity 41a of the upper half portion 41, the first area center of gravity 42a of the lower half portion 42, the projection points 41b, 42b, and the midpoint 43 is not limited to the repair structure 400 according to the fourth embodiment, but is similarly applicable to the repair structure 100, the repair structure 200, and the repair structure 300. In addition, the above relationship may also be applicable to other embodiments.

[0055] 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 think of various modified or altered examples within the scope of the claims, and it is understood that these also naturally belong to the technical scope of the present disclosure.

[0056] For example, in the second embodiment described above, the second side 3e of the repair member 3 is curved in the opposite direction to the central axis 3a. However, in other embodiments, the second side 3e may be straight instead of curved.

[0057] In the above embodiment, the repair structures 100, 200, 300, 400 are applied to the crack 50 that occurs in the plate-shaped base material 1. However, in other embodiments, the repair structures 100, 200, 300, 400 may be applied to, for example, a crack that occurs 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 members 2, 3 may be configured to be fitted across the multiple base materials.

[0058] This disclosure can promote better repairs of structures, thereby contributing to Goal 9 "Build resilient infrastructure, promote sustainable industrialization and foster innovation" and Goal 11 "Make cities inclusive, safe, resilient and sustainable" of the United Nations Sustainable Development Goals (SDGs). [Explanation of symbols]

[0059] 1 Base material 2 Repair materials 2a Center axis 2b Intersection 2d First edge 2e Second side 3 Repair materials 3a Center axis 3b intersection 4 Repair materials 4d First side 4e Second Edge 41 Upper half (first half) 41a First area centroid (first half area centroid) 41b Projection of the first area center of gravity onto the extension line of the crack 42 Lower half (second half) 42a Second area centroid (second half area centroid) 42b Projection of the second area center of gravity onto the extension of the crack 43 Midpoint 13 Repair hole 50 Crack 51 Crack End 100 Repair structure 200 Repaired Structure 300 Repair structure 400 Repair structure L Crack extension

Claims

1. A base material having a crack and a repair hole extending to intersect with the crack; a repair member that is inserted into the repair hole, and has a first side and a second side that extend so as to intersect with the crack and are located opposite each other, the first side being closer to an end of the crack than the second side, the repair member being between the first side and the second side, and including a central axis that is formed by connecting the midpoints of two points on the first side and the second side, the two points being taken so that a vertical distance from the crack to a point on the first side is equal to a vertical distance from the crack to a point on the second side, the central axis being curved at an intersection between the central axis and the crack so as to be away from the end of the crack compared to both ends of the central axis in the extension direction of the crack at the intersection, and the first side being curved in the same direction as the central axis; A repair structure comprising:

2. The repair structure according to claim 1 , wherein the second side is also curved in the same direction as the central axis.

3. The repair structure of claim 1 , wherein the second side is curved away from the central axis with a curvature that is smaller than a curvature of the first side.

4. A base material having a crack and a repair hole extending to intersect with the crack; a repair member that is inserted into the repair hole and extends to intersect with the crack and has a first side and a second side that are opposite to each other; a point obtained by projecting a first half area center of gravity, which is the area center of gravity of a first half of the repair member on a plane parallel to a plane in which the repair hole of the base material is formed, on the extension line of the crack, is located closer to an end of the crack in the extension direction of the crack than a midpoint between an intersection point of the crack and the first side and an intersection point of the crack and the second side; A point obtained by projecting a second half area center of gravity, which is the area center of gravity of a second half of the repair member on a plane parallel to a plane in which the repair hole of the base material is formed, on the extension line of the crack is closer to an end of the crack than the midpoint in the extension direction of the crack. Repair structure.

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