Optical fiber embedded ribbon

Abstract

To highly efficiently detect positions of cracks even when an interval between the cracks is small.SOLUTION: An optical fiber embedded tape 1A comprises an optical fiber 10, and a belt-like tape part 20 extending along an axial direction of the optical fiber 10 while being integrated with the optical fiber 10 and stuck to a surface of concrete to support the optical fiber 10. The tape part 20 includes fixing portions 21 for fixing the optical fiber 10 to a surface and non-fixing parts 22 not fixing the optical fiber 10 to the surface alternately along the axial direction of the optical fiber 10. When the tape part 20 is stuck to the surface and positions of cracks generated on the surface are detected based on strain generated in the optical fiber 10 at each of the non-fixing portions 22, a detection result of the strain of the non-fixing portions 22 is not affected by the strain at the other non-fixing portions 22 due to the fixing portions 21, so that even when an interval of cracks is small, this configuration can highly efficiently detect the positions of cracks.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an optical fiber embedded ribbon. [Background technology]

[0002] Techniques have been proposed for detecting the positions of cracks on the surface of concrete. For example, Patent Document 1 discloses a technique in which a strip-shaped sheet that is integrated with an optical fiber and adhered to the surface of the concrete to support the optical fiber is adhered to the surface of the concrete, and the position of a crack that has occurred on the surface of the concrete is detected based on the strain generated in the optical fiber. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-48516 A Summary of the Invention [Problem to be solved by the invention]

[0004] In the above-mentioned technology, the optical fiber measures the average strain in a set measurement section in the length direction of the optical fiber. When the cracks on the surface of the concrete are spaced widely apart, the optical fiber follows the sudden increase in strain at the crack position, increasing the strain of the optical fiber in a certain section around the crack, and the position of the crack can be detected based on the strain of the optical fiber.

[0005] However, when the cracks on the concrete surface are spaced apart, the effects of increased strain due to multiple cracks are mixed within one measurement section of the optical fiber, making it difficult to identify the location of the crack. In other words, because optical fiber adapts to the surrounding strain, even a local crack is detected as its strain is adapted over a large range. Therefore, one measurement section of the optical fiber measures the strain of the surrounding measurement sections mixed in. Therefore, when the cracks on the concrete surface are spaced apart, it makes it difficult to identify the location of the crack.

[0006] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide an optical fiber embedded ribbon that can detect the position of a crack with high accuracy even if the cracks occurring in the object to be measured are spaced apart closely. [Means for solving the problem]

[0007] The present invention is an optical fiber embedded tape comprising an optical fiber and a band-shaped tape portion that is integrated with the optical fiber, extends along the axial direction of the optical fiber, and is adhered to a measurement object to support the optical fiber, and the tape portion has alternating fixed portions that fix the optical fiber to the measurement object and non-fixed portions that do not fix the optical fiber to the measurement object along the axial direction of the optical fiber.

[0008] According to this configuration, the optical fiber embedded tape includes an optical fiber, and a band-shaped tape portion that is integrated with the optical fiber and extends along the axial direction of the optical fiber, and is attached to the measurement object to support the optical fiber, and the tape portion has, along the axial direction of the optical fiber, fixed portions that fix the optical fiber to the measurement object and non-fixed portions that do not fix the optical fiber to the measurement object, alternatingly arranged along the axial direction of the optical fiber. Therefore, when the tape portion is attached to the measurement object and the position of a crack that has occurred in the measurement object is detected based on the strain caused in the optical fiber in each of the non-fixed portions, the detection result of the strain caused in the optical fiber in each of the non-fixed portions is not affected by the strain caused in the optical fiber in other non-fixed portions by the fixed portions adjacent to them, so that the position of the crack can be detected more accurately even if the intervals between the cracks that have occurred in the measurement object are small.

[0009] In this case, the optical fiber includes a plurality of optical fibers having parallel axial directions, the tape portion extends along the axial direction of each of the optical fibers while being integrated with each of the optical fibers, and is adhered to the measurement object to support each of the optical fibers so that each of the optical fibers is arranged in parallel along the measurement object, and each of the optical fibers has fixed portions and non-fixed portions alternately along the axial direction of each of the optical fibers, and in adjacent optical fibers, the fixed portion for one optical fiber and the non-fixed portion for the other optical fiber may be adjacent to each other.

[0010] For cracks occurring in the fixing parts of the optical fibers, it can be difficult to detect the position of the crack, but with this configuration, there are provided a plurality of optical fibers whose axial directions are parallel, the tape part extends along the axial direction of each of the optical fibers while being integrated with each of the optical fibers, and is adhered to the measurement object to support each of the optical fibers such that each of the optical fibers is arranged in parallel along the measurement object, and for each of the optical fibers, fixed parts and non-fixed parts are alternately provided along the axial direction of each of the optical fibers, and in adjacent optical fibers, the fixed part of one optical fiber and the non-fixed part of the other optical fiber are adjacent to each other, and the non-fixed part of one optical fiber and the fixed part of the other optical fiber are adjacent to each other. Therefore, for a crack occurring in the fixing part of one optical fiber in adjacent optical fibers, the position of the crack can be detected as a crack occurring in the non-fixed part of the other optical fiber.

[0011] In addition, the fixed portion and non-fixed portion of the tape portion include an adhesive layer that is adhered to the measurement object via a primer that is applied to the measurement object to which the tape portion is adhered, and the adhesive layer of the non-fixed portion of the tape portion may be covered with a non-adhesive layer that does not chemically react with the primer.

[0012] According to this configuration, the fixed and non-fixed portions of the tape portion include an adhesive layer that is adhered to the measurement object via a primer that is applied to the measurement object to which the tape portion is adhered, and the adhesive layer of the non-fixed portion of the tape portion is covered with a non-adhesive layer that does not chemically react with the primer. Therefore, simply by attaching the tape portion to the measurement object to which the primer has been applied, it is possible to alternately form in the tape portion, along the axial direction of the optical fiber, fixed portions in which the optical fiber is adhered to the measurement object and non-fixed portions in which the optical fiber is not adhered to the measurement object.

[0013] In this case, when the tape portion is in a wound state, the adhesive layers of the fixed portion and non-fixed portion of the tape portion are covered with a non-adhesive layer which is a release sheet that assists in peeling the tape portion between adjacent wound layers, and the release sheet covering the fixed portion may be provided with a slit that assists in peeling the release sheet from the adhesive layer of the fixed portion.

[0014] According to this configuration, when the tape part is in a wound state, the adhesive layers of the fixed part and the non-fixed part of the tape part are covered with a non-adhesive layer that is a release sheet that assists in peeling the tape part between adjacent wound layers, so that the non-adhesive layer can serve as both a release sheet. The release sheet that covers the fixed part has a slit that assists in peeling the release sheet from the adhesive layer of the fixed part, so that the release sheet can be peeled from the adhesive layer of the fixed part by the slit, and the fixed part can be adhered to a measurement target to which a primer has been applied.

[0015] In addition, the fixed portion of the tape portion includes an adhesive layer that is adhered to the measurement object via a primer that is applied to the measurement object to which the tape portion is adhered, and the non-fixed portion of the tape portion does not need to include an adhesive layer.

[0016] According to this configuration, the fixed portion of the tape portion includes an adhesive layer that is adhered to the measurement object via a primer applied to the measurement object to which the tape portion is adhered, and the non-fixed portion of the tape portion does not include an adhesive layer. Therefore, by simply attaching the tape portion to the measurement object to which the primer has been applied, it is possible to alternately form fixed portions in which the optical fiber is adhered to the measurement object and non-fixed portions in which the optical fiber is not adhered to the measurement object in the axial direction of the optical fiber on the tape portion.

[0017] The fixed portion of the tape portion may support the optical fiber while being integrated with the optical fiber so that the optical fiber cannot move freely, and the non-fixed portion of the tape portion may support the optical fiber so that the optical fiber can move freely.

[0018] According to this configuration, the fixed portion of the tape portion supports the optical fiber while being integrated with the optical fiber so that the optical fiber cannot move freely, and the non-fixed portion of the tape portion supports the optical fiber so that the optical fiber can move freely. Therefore, by simply adhering the tape portion to the object to be measured, it is possible to alternately form in the tape portion, along the axial direction of the optical fiber, fixed portions in which the optical fiber is fixed to the object to be measured and non-fixed portions in which the optical fiber is not fixed to the object to be measured. Effect of the Invention

[0019] According to the optical fiber embedded ribbon of the present invention, the positions of cracks can be detected with high accuracy even if the intervals between cracks occurring in the object to be measured are small. [Brief description of the drawings]

[0020] [Figure 1] FIG. 1A is a side view showing the concept of detecting the positions of cracks on the surface of concrete using the optical fiber embedded tape according to the first embodiment, and FIG. 1B is a bottom view of FIG. [Diagram 2] 1 is a diagram illustrating the concept of spatial resolution and measurement interval of an optical fiber. [Diagram 3] FIG. 1A is a front view of the optical fiber embedded ribbon according to the first embodiment, and FIG. [Figure 4] FIG. 11 is a bottom view of the optical fiber embedded tape according to the second embodiment. [Diagram 5] (A) is a front view of the optical fiber embedded tape of the third embodiment, (B) is a side view of (A) and a side view showing the surface of concrete to which a primer has been applied, and (C) is a side view showing the tape portion of the optical fiber embedded tape of the third embodiment adhered to the concrete surface of (B). [Figure 6] FIG. 13(A) is a side view of the optical fiber embedded ribbon according to the fourth embodiment, and (B) is a bottom view of (A). [Figure 7] (A) is a plan view showing the surface of concrete on which an edge cutting sheet according to the fifth embodiment is installed, (B) is a longitudinal cross-sectional view of (A) using alpha rays, (C) is a front view of the optical fiber embedded tape according to the fifth embodiment, (D) is a longitudinal cross-sectional view of (C) using beta rays and (B) showing the surface of concrete to which a primer has been applied, and (E) is a longitudinal cross-sectional view showing the state in which the tape portion of the optical fiber embedded tape according to the fifth embodiment has been adhered to the surface of the concrete in (D). [Figure 8] FIG. 13(A) is a front view of an optical fiber embedded ribbon according to a sixth embodiment, (B) is a side view of (A), and (C) is a bottom view of (B). [Figure 9] FIG. 13(A) is a front view of an optical fiber embedded ribbon according to a seventh embodiment, (B) is a side view of (A), and (C) is a plan view of (B). [Figure 10] FIG. 1A is a diagram showing the results of crack detection using an optical fiber when the cracks are spaced apart widely, and FIG. 1B is a diagram showing the results of crack detection when the cracks are spaced apart narrowly. [Figure 11] FIG. 1 is a longitudinal cross-sectional view showing the state in which the tape portion of the optical fiber embedded tape of the first embodiment is adhered near the boundary between an FRP sheet wrapped around the surface of concrete for reinforcement and a surface of concrete that is not wrapped with the FRP sheet. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0021] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. First, the concept of detecting the position of a crack in a measurement target using an optical fiber embedded tape according to a first embodiment of the present invention will be described. As shown in Fig. 1(A) and Fig. 1(B), in detecting the position of a crack in the surface of concrete, which is a measurement target, using the optical fiber embedded tape of this embodiment, for example, the position of a crack 102 occurring in the surface 101 of concrete 100 in which reinforcing bars 103 are embedded is detected. The crack 102 in the surface 101 of concrete 100, the position of which is detected in this embodiment, means, for example, a structural crack that is known to occur at regular intervals in the surface 101 of concrete 100.

[0022] 1(A) and 1(B), in this embodiment, the optical fiber 10 is placed on the surface 101 of the concrete 100 so that the optical fiber 10 has alternately fixed portions 21 that are fixed to the surface 101 of the concrete 100 and non-fixed portions 22 that are not fixed to the surface 101 of the concrete 100. In this embodiment, the position of a crack 102 that has occurred on the surface 101 of the concrete 100 is detected based on the strain generated in the optical fiber 10 at each of the fixed portions 21.

[0023] The length L of the non-fixed portion 22 is longer than the interval S of the spatial resolution of the optical fiber 10. The interval g1 between the measurement points 50 at which each position of the strain generated in the optical fiber 10 shown in Fig. 2 can be resolved and detected is determined by the measurement method of the strain generated in the optical fiber 10. The interval g1 at which each position of the strain generated in the optical fiber 10 can be resolved and detected means the interval at which data of the strain generated in the optical fiber 10 is acquired. The spatial resolution means, for example, that an average strain in the interval S of the spatial resolution is detected.

[0024] 1(A) and 1(B), the length L of the non-fixed portion 22 is shorter than the expected interval g2 of the cracks 102 on the surface 101 of the concrete 100. The expected interval g2 of the cracks 102 on the surface 101 of the concrete 100 is calculated by multiplying the cover c of the reinforcing bars 103 embedded in the concrete 100 and the center interval c of each of the reinforcing bars 103. s and the diameter φ of the reinforcing bar. For example, the expected spacing g2 of cracks 102 on the surface 101 of concrete 100 is spacing g2 = 4 × cover c + 0.7 (center spacing c s -Diameter φ) can be used to calculate the

[0025] Moreover, the optical fiber 10 is placed on the surface 101 of the concrete 100 so that the expected direction of cracks 102 on the surface 101 of the concrete 100 intersects with the axial direction of the optical fiber 10. It is preferable that the expected direction of cracks 102 on the surface 101 of the concrete 100 and the axial direction of the optical fiber 10 are perpendicular to each other.

[0026] For example, the frequency of the Brillouin scattered light changes in proportion to the magnitude of the strain in the optical fiber 10. In this embodiment, an optical pulse of a predetermined frequency is input into one end of the optical fiber 10, and the change in optical frequency in the Brillouin scattered light generated by the optical pulse is measured at one end of the optical fiber along with the time indicating the generation position, thereby measuring the axial strain of the optical fiber 10.

[0027] When a crack 102 occurs at a position on the surface 101 of the concrete 100 corresponding to the non-fixed portion 22 where the optical fiber 10 is not fixed to the surface 101 of the concrete 100, the elongation of the optical fiber 10 at the non-fixed portion 22, with the fixed portion 21 where the optical fiber 10 is fixed to the surface 101 of the concrete 100 as a reference point, is approximately equal to the width of the crack 102. The elongation of the optical fiber 10 at the non-fixed portion 22 can be found by integrating the strain of the optical fiber 10 between the fixed portions 21, which are the reference points, in the axial direction of the optical fiber 10. Therefore, a step of detecting the width of the crack 102 occurring in the non-fixed portion 22 by integrating the strain occurring in the non-fixed portion 22 may be performed.

[0028] That is, since the fixed portion 21 is firmly fixed to the surface 101 of the concrete 100, if strain is detected in the non-fixed portion 22, the elongation of the optical fiber 10 in the non-fixed portion 22 becomes the width of the crack 102. If no strain is detected in the non-fixed portion 22, this means that there is no crack 102 in that non-fixed portion 22 or in the fixed portion 21 adjacent to that non-fixed portion 22.

[0029] The elongation of the optical fiber 10 in the non-fixed portions 22 caused by the cracks 102 is limited between the non-fixed portions 22 where the optical fiber 10 is not fixed to the surface 101 of the concrete 100, so it is possible to identify the position where the cracks 102 have occurred. In other words, the strain generated in the optical fiber 10 is detected using each of the fixed portions 21 as an independent reference point, and there is no interference between the detection results of the strain in the non-fixed portions 22. In this embodiment, the position where the cracks 102 have occurred is limited to the non-fixed portions 22. From the strain of the optical fiber 10 in each of the non-fixed portions 22, the cracks 102 in the surface 101 of the concrete 100 at the locations corresponding to each of the non-fixed portions 22 are identified.

[0030] 3(A) and 3(B), the optical fiber embedded tape 1A of this embodiment, which is applied to detecting the positions of cracks on the surface of concrete as described above, comprises an optical fiber 10 and a strip-shaped tape portion 20 that is integrated with the optical fiber 10 while extending along the axial direction of the optical fiber 10 and is adhered to the surface 101 of the concrete 100 to support the optical fiber 10. As described above, the tape portion 20 has alternating fixed portions 21 that fix the optical fiber 10 to the surface 101 of the concrete 100 and non-fixed portions 22 that do not fix the optical fiber 10 to the surface 101 of the concrete 100 along the axial direction of the optical fiber 10.

[0031] 3(A), the tape portion 20 has a base material 23 laminated in the order approaching the surface 101 of the concrete 100, and a protective layer 24 that encases and protects the optical fiber 10. On the side of the protective layer 24 closer to the surface 101 of the concrete 100, the fixed portion 21 of the tape portion 20 includes an adhesive layer 25 that is adhered to the surface 101 of the concrete 100 via a primer that is applied to the surface 101 of the concrete 100 to which the tape portion 20 is adhered. On the other hand, the non-fixed portion 22 of the tape portion 20 does not include the adhesive layer 25.

[0032] In other words, in this embodiment, the optical fiber 10 includes an adhesive layer 25, and a fixed portion 21 is formed at a location where the optical fiber 10 is adhered to the surface 101 of the concrete 100, and the optical fiber 10 does not include an adhesive layer 25, and a non-fixed portion 22 is formed at a location where the optical fiber 10 is not adhered to the surface 101 of the concrete 100.

[0033] For comparison with the conventional technology, as shown in Fig. 10(A) and Fig. 10(B), the optical fiber 10 was installed over the entire length of the surface 101 of the concrete 100 as a test specimen, so that there was no unfixed portion, and cracks 102 that occurred on the surface 101 of the concrete 100 were detected. In the figures, the "crack width" is a value measured by a pie-shaped displacement meter installed on the surface 101 of the concrete 100 as a test specimen. As shown in Fig. 10(A), when the interval between the cracks 102 is large, the optical fiber 10 follows the sudden increase in strain at the crack position, and the strain of the optical fiber 10 in a certain section around the crack 102 increases, and it can be seen that the position of each crack 102 can be detected from the detection result by the optical fiber 10.

[0034] However, as shown in FIG. 10B, when the intervals between the cracks 102 are small, the influence of the increase in strain due to the multiple cracks 102 is mixed in the measurement section of one point of the optical fiber 10 where the average strain of the measurement section is obtained, so the position of each crack 102 cannot be identified from the detection result of the strain distribution by the optical fiber 10 attached by the conventional method. In other words, as described above, the optical fiber 10 adapts to the surrounding strain, so even if the crack 102 is localized, the strain is detected by adapting to a large range. Therefore, in one measurement section of the optical fiber 10, the strain of the surrounding measurement sections is also measured. Therefore, when the intervals between the cracks 102 generated on the surface 101 of the concrete 100 are small, it is difficult to identify the position of the crack 102.

[0035] On the other hand, in this embodiment, the optical fiber embedded tape 1A comprises an optical fiber 10 and a band-shaped tape portion 20 that is integrated with the optical fiber 10, extends along the axial direction of the optical fiber 10, and is adhered to the surface 101 of the concrete 100 to support the optical fiber 10, and the tape portion 20 has alternating fixed portions 21 that fix the optical fiber 10 to the surface 101 of the concrete 100 and non-fixed portions 22 that do not fix the optical fiber 10 to the surface 101 of the concrete 100 along the axial direction of the optical fiber 10.

[0036] Therefore, when the tape portion 20 is adhered to the surface 101 of the concrete 100 and the position of cracks 102 that have occurred on the surface 101 of the concrete 100 is detected based on the strain that has occurred in the optical fiber 10 in each of the non-fixed portions 22, the detection result of the strain that has occurred in the optical fiber 10 in each of the non-fixed portions 22 is not affected by the strain that has occurred in the optical fiber 10 in the other non-fixed portions 22 by the adjacent fixed portions 21, thereby improving the resolution for detecting the cracks 102 and allowing the position of each crack 102 to be detected more accurately even if the cracks 102 that have occurred on the surface 101 of the concrete 100 are spaced apart closely.

[0037] Furthermore, when the entire optical fiber 10 is fixed to the surface 101 of the concrete 100, if a crack 102 occurs on the surface 101 of the concrete 100, the strain of the optical fiber 10 increases rapidly in the vicinity of the position of the crack 102, limiting the elongation of the optical fiber 10, and there is a possibility that measurement will become impossible due to deviation from the measurement range and early breakage of the optical fiber 10. On the other hand, in this embodiment, the strain is averaged within the range of the length L of the non-fixed portion 22 where the optical fiber 10 is not fixed to the surface 101 of the concrete 100, so that it is possible to reduce the possibility of deviation from the measurement range and early breakage of the optical fiber 10, making measurement impossible.

[0038] In this embodiment, the fixed portion 21 of the tape portion 20 includes an adhesive layer 25 that is adhered to the surface 101 of the concrete 100 via a primer that is applied to the surface 101 of the concrete 100 to which the tape portion 20 is adhered, and the non-fixed portion 22 of the tape portion 20 does not include an adhesive layer 25. Therefore, by simply attaching the tape portion 20 to the surface 101 of the concrete 100 to which a primer is applied, the fixed portion 21 in which the optical fiber 10 is adhered to the surface 101 of the concrete 100 and the non-fixed portion 22 in which the optical fiber 10 is not adhered to the surface 101 of the concrete 100 can be alternately formed in the tape portion 20 along the axial direction of the optical fiber 10, and it becomes easy to alternately form the fixed portion 21 and the non-fixed portion 22 when the optical fiber embedded tape 1A is attached to the surface 101 of the concrete 100.

[0039] A second embodiment of the present invention will be described below. As shown in Fig. 4, the optical fiber embedded tape 1B of this embodiment includes a plurality of optical fibers 10 whose axial directions are parallel. In the example of Fig. 4, the optical fiber embedded tape 1B includes two optical fibers 10, but may include three or more optical fibers 10. The tape portion 20 extends along the axial direction of each of the optical fibers 10 while being integrated with each of the optical fibers 10, and is adhered to the surface 101 of the concrete 100 to be measured, and supports each of the optical fibers 10 so that each of the optical fibers 10 is arranged in parallel along the surface 101 of the concrete 100.

[0040] The tape section 20 has, for each of the optical fibers 10, fixed portions 21 and non-fixed portions 22 alternately along the axial direction of each of the optical fibers 10. In the tape section 20, for adjacent optical fibers 10, the fixed portion 21 for one optical fiber 10 and the non-fixed portion 22 for the other optical fiber 10 are adjacent to each other. In the tape section 20, for adjacent optical fibers 10, the non-fixed portion 22 for one optical fiber 10 and the fixed portion 21 for the other optical fiber 10 are adjacent to each other.

[0041] For a crack 102 that occurs in the fixed portion 21 of the optical fiber 10, it may be difficult to detect the position of the crack 102. However, according to this embodiment, a plurality of optical fibers 10 having parallel axial directions are provided. The tape portion 20 extends along the axial direction of each of the optical fibers 10 while being integrated with each of the optical fibers 10, and is adhered to the surface 101 of the concrete 100 to support each of the optical fibers 10 such that each of the optical fibers 10 is arranged in parallel along the surface 101 of the concrete 100, and each of the optical fibers 10 has fixed portions 21 and non-fixed portions 22 alternating along the axial direction of each of the optical fibers 10.

[0042] In the tape portion 20, in adjacent optical fibers 10, the fixed portion 21 of one optical fiber 10 and the non-fixed portion 22 of the other optical fiber 10 are adjacent to each other, and the non-fixed portion 22 of one optical fiber 10 and the fixed portion 21 of the other optical fiber 10 are adjacent to each other. Therefore, even if a crack occurs in the fixed portion 21 of one optical fiber 10 in adjacent optical fibers 10, the position of the crack can be detected as a crack occurring in the non-fixed portion 22 of the other optical fiber 10.

[0043] A third embodiment of the present invention will be described below. As shown in Fig. 5(A) and Fig. 5(B), in an optical fiber embedded tape 1C of this embodiment, the fixed part 21 and the non-fixed part 22 of the tape part 20 include an adhesive layer 25 that is adhered to the surface 101 of the concrete 100 via a primer 31 that is applied to the surface 101 of the concrete 100, which is the measurement target to which the tape part 20 is adhered. The adhesive layer 25 of the non-fixed part 22 of the tape part 20 is covered with a non-adhesive layer 26 that does not chemically react with the primer 31.

[0044] As shown in Fig. 5(B), a primer 31 is applied to the surface 101 of the concrete 100 over the entire length of the measurement range of the optical fiber 10. As shown in Fig. 5(C), the tape portion 20 of the optical fiber embedded tape 1C is attached to the surface 101 of the concrete 100 to which the primer 31 has been applied.

[0045] In the area where the adhesive layer 25 is not covered by the non-adhesive layer 26, the optical fiber 10 is fixed to the surface 101 of the concrete 100 by the adhesive layer 25. However, in the area where the adhesive layer 25 is covered by the non-adhesive layer 26, the adhesive layer 25 is cut off from the surface of the concrete 100, and the optical fiber 10 is not fixed to the surface 101 of the concrete 100 by the adhesive layer 25. That is, in this embodiment, the fixing portion 21 is formed in the area where the adhesive layer 25 is not covered by the non-adhesive layer 26, and the non-fixing portion 22 is formed in the area where the adhesive layer 25 is covered by the non-adhesive layer 26.

[0046] In this embodiment, the adhesive layer 25 of the non-fixed portion 22 of the tape portion 20 is coated with a non-adhesive layer 26 that does not chemically react with the primer 31. Therefore, simply by attaching the tape portion 20 to the surface 101 of the concrete 100 to which the primer 31 has been applied, fixed portions 21 in which the optical fiber 10 is adhered to the surface 101 of the concrete 100 and non-fixed portions 22 in which the optical fiber 10 is not adhered to the surface 101 of the concrete 100 can be formed alternately in the tape portion 20 along the axial direction of the optical fiber 10. This makes it easy to form the fixed portions 21 and the non-fixed portions 22 alternately when attaching the optical fiber embedded tape 1C to the surface 101 of the concrete 100.

[0047] The fourth embodiment of the present invention will be described below. As shown in Figures 6(A) and 6(B), in the optical fiber embedded tape 1D of this embodiment, as in the above-mentioned third embodiment, the fixed part 21 and the non-fixed part 22 of the tape part 20 include an adhesive layer 25 that is adhered to the surface 101 of the concrete 100 via a primer 31 that is applied to the surface 101 of the concrete 100, which is the measurement target to which the tape part 20 is adhered.

[0048] In the optical fiber embedded tape 1D of this embodiment, when the tape portion 20 is wound around the core, the adhesive layers 25 of the fixed portion 21 and the non-fixed portion 22 of the tape portion 20 are covered with a non-adhesive layer 26, which is a release sheet 27 that assists in peeling the tape portion 20 between adjacent wound layers. The release sheet 27 that covers the fixed portion 21 has a slit 28 that assists in peeling the release sheet 27 from the adhesive layer 25 of the fixed portion 21.

[0049] In this embodiment, when the tape part 20 is in a wound state, the adhesive layer 25 of the fixed part 21 and the non-fixed part 22 of the tape part 20 is covered with a non-adhesive layer 26 that is a release sheet 27 that assists in peeling the tape part 20 between adjacent wound layers, so that the non-adhesive layer 26 can be used as the release sheet 27. The release sheet 27 that covers the fixed part 21 has a slit 28 that assists in peeling the release sheet 27 from the adhesive layer 25 of the fixed part 21, so that the release sheet 27 can be peeled from the adhesive layer 25 of the fixed part 21 by the slit 28, and the fixed part 21 can be adhered to the surface 101 of the concrete 100 to which the primer 31 has been applied, as in the third embodiment.

[0050] A fifth embodiment of the present invention will be described below. As shown in Fig. 7(A) and Fig. 7(B), in this embodiment, an edge cutting sheet 32 ​​having holes 33 at regular intervals along the axial direction of the optical fiber 10 is placed in advance on the surface 101 of the concrete 100 to be measured. Instead of the edge cutting sheet 32, an edge cutting tape having holes at regular intervals along the axial direction of the optical fiber 10 may be attached to the surface 101 of the concrete 100 in advance.

[0051] As shown in Figures 7(C) and 7(D), in the optical fiber embedded tape 1E of this embodiment, the fixed portion 21 and the non-fixed portion 22 of the tape portion 20 include an adhesive layer 25 that is adhered to the surface 101 of the concrete 100 via a primer 31 that is applied to the surface 101 of the concrete 100 to which the tape portion 20 is adhered. The primer 31 is applied to the surface 101 of the concrete 100 via an edge-cutting sheet 32. The primer 31 is preferably applied not by the conventional method using a stick, but by a method of spraying the primer 31 onto the surface 101 of the concrete 100 by a spray method. The tape portion 20 is attached to the surface 101 of the concrete 100 via the edge-cutting sheet 32.

[0052] 7(E), in the area where the adhesive layer 25 contacts the primer 31 through the hole 33 of the edge cutting sheet 32, the optical fiber 10 is fixed to the surface 101 of the concrete 100 by the adhesive layer 25. However, in the area other than the hole 33 of the edge cutting sheet 32, the adhesive layer 25 does not contact the primer 31, the adhesive layer 25 is cut off from the surface 101 of the concrete 100, and the optical fiber 10 is not fixed to the surface 101 of the concrete 100 by the adhesive layer 25. That is, in this embodiment, the fixing portion 21 is formed in the area of ​​the hole 33 of the edge cutting sheet 32, and the non-fixing portion 22 is formed in the area other than the hole 33 of the edge cutting sheet 32.

[0053] According to this embodiment, the fixed portion 21 and the non-fixed portion 22 of the tape portion 20 include an adhesive layer 25 that is adhered to the surface 101 of the concrete 100 via a primer 31 that is applied to the surface 101 of the concrete 100 to which the tape portion 20 is adhered. In addition, an edge cutting sheet 32 ​​having holes 33 at regular intervals along the axial direction of the optical fiber 10 is placed on the surface 101 of the concrete 100 in advance, and then the primer 31 is applied to the surface 101 of the concrete 100 via the edge cutting sheet 32, and the tape portion 20 is attached to the surface 101 of the concrete 100 via the edge cutting sheet 32. In this way, the fixed portion 21 in which the optical fiber 10 is adhered to the surface 101 of the concrete 100 and the non-fixed portion 22 in which the optical fiber 10 is not adhered to the surface 101 of the concrete 100 can be alternately formed in the tape portion 20 along the axial direction of the optical fiber 10, and it becomes easy to alternately form the fixed portion 21 and the non-fixed portion 22 when the optical fiber embedded tape 1E is attached to the surface 101 of the concrete 100.

[0054] A sixth embodiment of the present invention will be described below. As shown in Fig. 8(A), Fig. 8(B) and Fig. 8(C), in the optical fiber embedded tape 1F of this embodiment, the fixed part 21 of the tape part 20 includes an adhesive layer 25 that is adhered to the surface 101 of the concrete 100 via a primer 31 that is applied to the surface 101 of the concrete 100 that is the measurement target to which the tape part 20 is adhered, and the non-fixed part 22 of the tape part 20 does not include the adhesive layer 25. The adhesive layer 25 has holes 29 at regular intervals along the axial direction of the optical fiber 10. In the holes 29, the optical fiber 10 is exposed. In order to protect the optical fiber 10, a protective layer or protective tape that covers the optical fiber 10 in the holes 29 may be provided.

[0055] The tape portion 20 of the optical fiber embedded tape 1F is attached to the surface 101 of the concrete 100 to which the primer 31 has been applied. In the areas where the adhesive layer 25 contacts the primer 31 other than the hole portions 29 of the adhesive layer 25, the optical fiber 10 is fixed to the surface 101 of the concrete 100 by the adhesive layer 25. However, in the areas of the hole portions 29 of the adhesive layer 25, the optical fiber 10 is cut off from the surface 101 of the concrete 100, and the optical fiber 10 is not fixed to the surface 101 of the concrete 100. That is, in this embodiment, the fixed portions 21 are formed in the areas of the adhesive layer 25 other than the hole portions 29, and the non-fixed portions 22 are formed in the areas of the hole portions 29 of the adhesive layer 25.

[0056] In this embodiment, the fixed portion 21 of the tape portion 20 includes an adhesive layer 25 that is adhered to the surface 101 of the concrete 100 via a primer 31 that is applied to the surface 101 of the concrete 100 to which the tape portion 20 is adhered, and the non-fixed portion 22 of the tape portion 20 does not include an adhesive layer 25. Therefore, by simply attaching the tape portion 20 to the surface 101 of the concrete 100 to which the primer 31 has been applied, the fixed portions 21 in which the optical fiber 10 is adhered to the surface 101 of the concrete 100 and the non-fixed portions 22 in which the optical fiber 10 is not adhered to the surface 101 of the concrete 100 can be alternately formed in the tape portion 20 along the axial direction of the optical fiber 10, making it easy to form the fixed portions 21 and the non-fixed portions 22 alternately when attaching the optical fiber embedded tape 1F to the surface 101 of the concrete 100.

[0057] The seventh embodiment of the present invention will be described below. As shown in Figures 9(A), 9(B) and 9(C), in an optical fiber embedded tape 1G of this embodiment, a fixed portion 21 of a tape portion 20 supports the optical fiber 10 while being integrated with the optical fiber 10 so that the optical fiber 10 cannot move freely. On the other hand, a non-fixed portion 22 of the tape portion 20 supports the optical fiber 10 so that the optical fiber 10 can move freely.

[0058] The tape unit 20 has an adhesive layer 25, a substrate 23, and a protective layer 24 that encloses and protects the optical fiber 10, which are layered in an order that increases from the surface 101 of the concrete 100 to be measured. Protective tubes 34 having an inner diameter larger than the outer diameter of the optical fiber 10 are arranged in the protective layer 24 of the tape unit 20 at regular intervals along the axial direction of the optical fiber 10. In the portion of the protective layer 24 where the protective tube 34 is not arranged, the optical fiber 10 is integrated with the protective layer 24 so that the optical fiber 10 cannot move freely. In the portion of the protective layer 24 where the protective tube 34 is arranged, the optical fiber 10 is surrounded by the protective tube 34 so that the optical fiber 10 can move freely.

[0059] The tape portion 20 of the optical fiber embedded tape 1G is attached to the surface 101 of the concrete 100 to which the primer 31 has been applied. In the portion of the protective layer 24 other than the portion where the protective tube 34 is disposed, the optical fiber 10 integrated with the protective layer 24 is fixed to the surface 101 of the concrete 100 by the adhesive layer 25. However, in the portion of the protective layer 24 where the protective tube 34 is disposed, the optical fiber 10 surrounded by the protective tube 34 is movable within the protective tube 34, is cut off from the surface 101 of the concrete 100, and is not fixed to the surface 101 of the concrete 100. That is, in this embodiment, the fixed portion 21 is formed in the portion other than the protective tube 34, and the non-fixed portion 22 is formed in the portion of the protective tube 34.

[0060] In this embodiment, the fixed portion 21 of the tape portion 20 supports the optical fiber 10 while being integrated with the optical fiber 10 so that the optical fiber 10 cannot move freely, and the non-fixed portion 22 of the tape portion 20 supports the optical fiber 10 so that the optical fiber 10 can move freely. Therefore, simply by adhering the tape portion 20 to the surface 101 of the concrete 100, the fixed portions 21 in which the optical fiber 10 is fixed to the surface 101 of the concrete 100 and the non-fixed portions 22 in which the optical fiber 10 is not fixed to the surface 101 of the concrete 100 can be alternately formed in the tape portion 20 along the axial direction of the optical fiber 10, making it easy to form the fixed portions 21 and the non-fixed portions 22 alternately when attaching the optical fiber embedded tape 1G to the surface 101 of the concrete 100.

[0061] Although the embodiments of the present invention have been described above, the present invention is not limited to the above embodiments and may be embodied in various forms. For example, the above embodiments have been described mainly with reference to the case where the measurement target is the surface 101 of the concrete 100, but the tape portion 20 of the optical fiber embedded tapes 1A, 1B, 1C, 1D, 1E, 1F, and 1G of the above embodiments may be bonded to a steel material and a FRP (Fiber Reinforced Plastics) sheet.

[0062] For example, as shown in Fig. 11, the optical fiber embedded ribbons 1A, 1B, 1C, 1D, 1E, 1F, and 1G of the present embodiment can be applied to a case where an FRP sheet 200 is wound around a surface 101 of a concrete 100 for reinforcement. A fixed portion 21 where the optical fiber 10 of the optical fiber embedded ribbon 1A is fixed is formed between the FRP sheet 200 wound around the surface 101 of the concrete 100 for reinforcement and the surface 101 of the concrete 100 where the FRP sheet 200 is not wound. A non-fixed portion 22 where the optical fiber 10 is not fixed is formed near the boundary between the FRP sheet 200 wound around the surface 101 of the concrete 100 and the surface 101 of the concrete 100 where the FRP sheet 200 is not wound so that the optical fiber embedded ribbon 1A can overcome the step at the boundary. This makes it possible to detect the displacement of the FRP sheet 200 indicated by the arrow in Fig. 11. [Explanation of symbols]

[0063] 1A, 1B, 1C, 1D, 1E, 1F, 1G...optical fiber embedded tape, 10...optical fiber, 20...tape portion, 21...fixed portion, 22...non-fixed portion, 23...base material, 24...protective layer, 25...adhesive layer, 26...non-adhesive layer, 27...peeling sheet, 28...cut, 29...hole, 31...primer, 32...edge cutting sheet, 33...hole, 34...protective tube, 50...measurement point, 100...concrete, 101...surface, 102...crack, 103...reinforcing bar, 200...FRP sheet, L...length, g1, g2...spacing, S...section, c...cover, c s ...Center spacing, φ...Diameter.

Claims

1. An optical fiber; a strip-shaped tape portion that is integrated with the optical fiber, extends along an axial direction of the optical fiber, and is adhered to a measurement target to support the optical fiber; Equipped with The tape portion is an optical fiber embedded tape having alternating fixed portions along the axial direction of the optical fiber, the fixed portions including an adhesive layer that can be adhered to the measurement object and fix the optical fiber to the measurement object, and non-fixed portions that do not include the adhesive layer and do not fix the optical fiber to the measurement object.

2. An optical fiber; a strip-shaped tape portion that is integrated with the optical fiber, extends along an axial direction of the optical fiber, and is adhered to a measurement target to support the optical fiber; Equipped with the tape portion has, alternately along the axial direction of the optical fiber, fixed portions that fix the optical fiber to the measurement object and non-fixed portions that do not fix the optical fiber to the measurement object, A plurality of the optical fibers are provided, the optical fibers being parallel in the axial direction, The tape portion is a measuring section for measuring the length of each of the optical fibers, the measuring section being bonded to the measurement object and extending along the axial direction of each of the optical fibers while being integral with each of the optical fibers; and the measuring section being bonded to the measurement object, the measuring section being bonded to the measurement object and supporting each of the optical fibers such that each of the optical fibers is arranged in parallel along the measurement object; For each of the optical fibers, the fixed portion and the non-fixed portion are alternately arranged along the axial direction of each of the optical fibers, In the adjacent optical fibers, the fixed portion of one of the optical fibers and the non-fixed portion of the other of the optical fibers are adjacent to each other, An optical fiber embedded tape, wherein the non-fixed portion of one of the optical fibers and the fixed portion of the other of the optical fibers are adjacent to each other.

3. An optical fiber; a strip-shaped tape portion that is integrated with the optical fiber, extends along an axial direction of the optical fiber, and is adhered to a measurement target to support the optical fiber; Equipped with the tape portion has, alternately along the axial direction of the optical fiber, fixed portions that fix the optical fiber to the measurement object and non-fixed portions that do not fix the optical fiber to the measurement object, the fixed portion and the non-fixed portion of the tape portion include an adhesive layer that is adhered to the measurement object via a primer that is applied to the measurement object to which the tape portion is adhered, An optical fiber embedded tape, wherein the adhesive layer of the non-fixed portion of the tape portion is covered with a non-adhesive layer that does not chemically react with the primer.

4. The optical fiber embedded tape of claim 3, wherein when the tape portion is in a wound state, the adhesive layers of the fixed portion and the non-fixed portion of the tape portion are covered by the non-adhesive layer which is a release sheet that assists in peeling the tape portion between adjacent winding layers, and the release sheet covering the fixed portion is provided with a slit that assists in peeling the release sheet from the adhesive layer of the fixed portion.

5. An optical fiber; a strip-shaped tape portion that is integrated with the optical fiber, extends along an axial direction of the optical fiber, and is adhered to a measurement target to support the optical fiber; Equipped with the tape portion has, alternately along the axial direction of the optical fiber, fixed portions that fix the optical fiber to the measurement object and non-fixed portions that do not fix the optical fiber to the measurement object, the fixing portion of the tape portion includes an adhesive layer that is adhered to the measurement object via a primer that is applied to the measurement object to which the tape portion is adhered, The optical fiber embedded tape, wherein the non-fixed portion of the tape portion does not include the adhesive layer.

6. the fixing portion of the tape portion supports the optical fiber while being integrated with the optical fiber so that the optical fiber cannot move freely; 3. The optical fiber embedded tape according to claim 1, wherein the non-fixed portion of the tape portion supports the optical fiber so that the optical fiber can move freely.

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