JP2017078618A - Strain management system and strain management method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a strain management system and the like that can suitably perform strain management.SOLUTION: A strain management system 1 is used for strain management when pre-stress is introduced to a girder material 60. The strain management system 1 comprises: an optical fiber cable 12 attached in a longitudinal direction of a PC steel material 10 with optical fiber integrated thereinto; a measuring instrument 20 for measuring strain distribution of the optical fiber cable 12 in the longitudinal direction of the optical fiber; and a PC 30 for calculating friction information on friction which the PC steel material 10 with optical fiber integrated thereinto receives from surroundings from the strain distribution when the PC steel material 10 with optical fiber integrated thereinto is strained.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a tension management system and a tension management method for managing tension of a tension material.

  As examples of reinforcement by tension of a tension material, there are a case where prestress is introduced into the structure by the tension material and a case where compressive force is introduced into the ground by a ground anchor cable which is a tension material.

  In these cases, it is necessary to appropriately perform tension management. As an example of the management, one that measures tension of a tension material by a magnetostrictive sensor is known (for example, see Patent Document 1). This utilizes the fact that the magnetic properties of tendons such as PC steel materials depend on the strain of the tendons, and measures the magnetic properties of the tendons to determine the strain (tension) of the tendons.

JP 2012-127053

  When the tension material is tensioned, loss of tension occurs due to friction between the tension material and the surroundings. For this reason, tension is managed in consideration of the loss due to friction by setting the range of friction coefficient variation at the time of tension. However, when the cable length and bending angle are large, the variation may become larger than expected. .

  The method of Patent Document 1 can use the measurement value obtained by the magnetostrictive sensor for management, but has a problem that only the local stress at the location where the magnetostrictive sensor is installed can be grasped. If the stress distribution along the entire length of the tendon can be grasped, the friction coefficient according to the cable length and the bending angle can be evaluated, so high-precision management is possible. The stress distribution cannot be grasped, and the installation cost is high, so that there is a disadvantage that the measurement points have to be narrowed down.

  The present invention has been made in view of the above problems, and an object thereof is to provide a tension management system and the like that can suitably perform tension management.

  1st invention for solving the subject mentioned above is the optical fiber cable attached along the longitudinal direction of a tension material, the strain distribution measuring device which measures strain distribution along the longitudinal direction of the optical fiber of an optical fiber cable, And a friction information calculating device that calculates friction information related to friction received by the tendon from the strain distribution when the tendon is tensioned.

The tension material applies prestress to the structure by, for example, tension.
Moreover, the tension management system of 1st invention calculates the temperature information regarding the temperature around the said tension material from the said strain distribution in at least any one before the filling of the filler around the said tension material, and at the time of filling. It is desirable to further include an information calculation device.

  The second invention measures the strain distribution along the longitudinal direction of the optical fiber of the optical fiber cable by the strain distribution measuring device when the tension material attached with the optical fiber cable along the longitudinal direction is strained, and the friction information calculating device Friction information on friction received by the tendon from the strain distribution during tension of the tendon is calculated.

It is desirable to tension another tension material with a tension force determined based on the friction information.
The tension material applies prestress to the structure by, for example, tension.
Moreover, after measuring the strain distribution, it is preferable that an end portion of the optical fiber cable is detached from the strain distribution measuring device and placed in a switch box provided in the structure.

In the tension management method according to the second aspect of the present invention, the strain distribution along the longitudinal direction of the optical fiber of the optical fiber cable is measured by the strain distribution measuring device at least one of before and during the filling of the filler around the tension material. It is desirable to measure and calculate temperature information related to the temperature around the tendon from the strain distribution at least before or during the filling of the filler with a temperature information calculation device.
In addition, when the grout cap is attached to the end of the tendon after the tension of the tendon, it is desirable that an optical fiber cable is passed through the hole of the grout cap.

  In the present invention, when tensioning a tension member attached with an optical fiber cable along the longitudinal direction, the friction that the tension material receives from the surroundings affects the strain of the tension material and hence the strain of the optical fiber of the optical fiber cable. Friction information on the friction received by tendons by measuring the strain distribution along the extension of BOTDR (Brillouin Optical Time Domain Reflectometer), BOCDA (Brillouin Optical Correlation Domain Analysis), FBG (Fiber Bragg Grating) method, etc. Can be obtained.

  In the present invention, since the strain distribution over the entire length of the optical fiber cable can be measured, more useful friction information in consideration of the friction over the entire length of the tendon can be obtained, which is useful for high-precision management of the tendon. For example, based on this friction information, more accurate tension management can be performed by setting the tension of another tension member in consideration of friction loss.

  Moreover, a high quality structure can be constructed by applying the management method of the present invention when prestress is introduced into the structure due to the tension of the tension material. After measurement of the strain distribution, the end of the optical fiber cable can be placed in a switch box provided in the structure, and can be used for management of the structure by measuring the strain distribution or the like.

  In addition, by utilizing the fact that the temperature around the tendon affects the strain of the tendon and hence the strain of the optical fiber of the optical fiber cable, temperature information related to the ambient temperature can be obtained from the strain distribution of the optical fiber as well. Since the temperature state over the entire length can be evaluated, it is also useful for high-precision temperature management and filling management when filling around the tension material. Also, when attaching the grout cap to the end of the tendon material, the end of the optical fiber cable is passed through the hole of the grout cap, so that the optical fiber cable can be suitably pulled out from the grout cap and connected to a strain distribution measuring device or the like. .

  According to the present invention, it is possible to provide a tension management system and the like that can suitably perform tension management.

The figure which shows the tension management system 1 Figure showing optical fiber built-in PC steel 10 The figure which shows the hardware constitutions of PC30 Flow chart showing tension management method Diagram showing tension T, friction F, and strain distribution of optical fiber built-in PC steel 10 The figure which shows the filling procedure of the grout material 63 Diagram explaining calculation of temperature distribution The figure which shows tension management system 1a The figure which shows tension management system 1 ' Flow chart showing tension management method The figure which shows switch box 66

  Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings.

[First embodiment]
(1. Tension management system 1)
Fig.1 (a) is a figure which shows the tension | tensile_strength management system 1 which concerns on the 1st Embodiment of this invention. As shown to Fig.1 (a), the tension | tensile_strength management system 1 has the optical fiber built-in type | mold PC steel material 10 (tensile material), the tension | tensile_strength management part 2, etc. FIG.

  The tension management system 1 performs tension management when prestress is introduced into a beam member 60 (structure) such as a main girder of a bridge as shown in FIG. FIG. 1 (b) shows a box girder as an example of the girder 60, and FIG. 1 (a) shows a part of the box girder.

  The optical fiber built-in PC steel material 10 is a PC steel material in which an optical fiber cable is attached along the longitudinal direction. The optical fiber built-in PC steel 10 is passed through the inside of the girder 60 and used as an inner cable, and the girder 60 is reinforced by introducing prestress.

  FIG. 2 is a view showing an optical fiber built-in PC steel material 10. FIG. 2A is a view of the end of the optical fiber built-in PC steel 10 viewed from the side, and FIG. 2B is a cross-sectional view in a direction perpendicular to the longitudinal direction of the optical fiber built-in PC steel 10. It is a figure.

  In this embodiment, a PC steel stranded wire in which six PC steel wires 11 are spirally twisted around a central PC steel wire 11 is used as the optical fiber built-in PC steel material 10.

  An optical fiber cable 12 (hereinafter also referred to as a cable) is spirally arranged on the outer surface of the optical fiber built-in PC steel 10 along the adjacent PC steel wires 11, and the length of the optical fiber built-in PC steel 10 is long. It is attached and integrated continuously over substantially the entire length along the direction. The cable 12 is obtained by coating an optical fiber with a coating material or the like, and is used for measuring a strain distribution along the longitudinal direction of the optical fiber by a known method such as BOTDR, BOCDA, or FBG.

  The cross section in the direction orthogonal to the longitudinal direction of each PC steel wire 11 is substantially circular, and the cross section in the direction orthogonal to the longitudinal direction of the cable 12 is substantially triangular. The cable 12 can be placed in a gap between the adjacent PC steel wires 11 by directing the apex of the substantially triangular cross section toward the central PC steel wire 11, and the optical fiber built-in shown by the dotted line in FIG. It can fit well in the circumscribed hexagon of the type PC steel 10. In addition, as long as it fits in the clearance gap between the adjacent PC steel wires 11, the cross section of the cable 12 may have other shapes, such as a round shape.

  In the spar 60, a longitudinal through hole is formed by a sheath tube. By inserting the optical fiber built-in PC steel material 10 into the through hole, both ends are tensioned and fixed to both ends of the spar 60, respectively. Prestress is introduced into the girder 60.

  The tension management unit 2 measures the strain distribution along the longitudinal direction of the optical fiber, the friction information about the friction received by the optical fiber built-in PC steel 10 from the strain distribution data, and the temperature around the optical fiber built-in PC steel 10 Calculate temperature information about.

  As shown in FIG. 1A, the tension management unit 2 includes a measuring device 20 (strain distribution measuring device), a PC 30 (friction information calculating device, temperature information calculating device), and the like.

  The measuring device 20 is connected to the cable 12, and enters the inspection light into the optical fiber, detects the reflected light from the optical fiber, and analyzes the reflected light to measure the strain distribution by a technique such as BOTDR, BOCDA, FBG, etc. . The measured strain distribution data is input to the PC 30.

  Techniques such as BOTDR, BOCDA, and FBG are known (see, for example, Japanese Patent Application Laid-Open No. 2008-224338, Japanese Patent Application Laid-Open No. 2009-236813, and Japanese Patent Application Laid-Open No. 2012-132927). The measuring device 20 injects inspection light into the optical fiber, detects Brillouin scattered light as reflected light, and analyzes its spectrum. Although details are omitted, the generation position of the reflected light is specified by the time delay from the incident of the inspection light to the detection of the reflected light, and the value of distortion at the position is obtained from the frequency shift amount in the reflected light.

  In the case of the BOCDA method, both ends of the cable 12 that is folded back are connected to the measuring device 20, and inspection light is incident from both ends of the optical fiber by the measuring device 20. Although details are omitted, in the BOCDA method, the position where the Brillouin scattered light is generated is controlled by controlling both inspection lights, and the distortion can be measured by obtaining the frequency shift amount from the Brillouin gain spectrum at that position. In both BOTDR and BOCDA systems, continuous strain distribution measurement along the longitudinal direction of the optical fiber can be performed.

  In the case of the FBG method, diffraction gratings having a changed refractive index are provided at a plurality of positions in the longitudinal direction of the optical fiber, and inspection light is incident on the optical fiber by the measuring device 20 to detect reflected light. Although details are omitted, the FBG method can measure the strain in each diffraction grating from the amount of frequency shift in the reflected light, and measures the strain distribution along the longitudinal direction of the optical fiber from the strain value at the position of each diffraction grating. be able to.

  The PC 30 displays the strain distribution data input from the measuring device 20, the friction information on the friction received by the optical fiber built-in PC steel 10 from the strain distribution data, and the temperature around the optical fiber built-in PC steel 10. Calculate temperature information.

  FIG. 3 is a diagram illustrating a hardware configuration of the PC 30. As shown in FIG. 3, the PC 30 can be realized by a computer configured by connecting a control unit 31, a storage unit 32, an input unit 33, a display unit 34, a communication unit 35, and the like through a bus 36. However, the present invention is not limited to this, and various configurations can be taken as appropriate.

  The control unit 31 includes a CPU, a ROM, a RAM, and the like. The CPU calls and executes a program related to the processing of the PC 30 stored in a storage medium such as the storage unit 32 and the ROM into a work memory area on the RAM. The ROM is a non-volatile memory, and permanently stores programs such as a computer boot program and BIOS, and data. The RAM is a volatile memory, and temporarily stores programs and data loaded from the storage unit 32, the ROM, and the like, and includes a work area used by the control unit 31 for performing various processes.

  The storage unit 32 is, for example, a hard disk drive, and stores a program executed by the control unit 31, data necessary for program execution, an OS, and the like. These programs and data are read by the control unit 31 as necessary, transferred to the RAM, and executed.

The input unit 33 inputs data and includes an input device such as a keyboard, a pointing device such as a mouse, and a numeric keypad.
The display unit 34 includes a display device such as a liquid crystal panel.
The communication unit 35 is a communication interface that mediates communication via a network, and performs communication with other devices.
The bus 36 is a path that mediates transmission / reception of control signals, data signals, and the like between the respective units.

(2. Tension management method)
Next, the tension management method according to the present embodiment will be described with reference to FIG. FIG. 4 is a flowchart showing a tension management method.

  In this embodiment, the optical fiber built-in PC steel material 10 is inserted into the through hole of the beam member 60 and arranged, and both ends thereof are passed through a tensioning jack. Further, after the optical fiber cable 12 at one end of the optical fiber built-in PC steel material 10 is peeled off and terminal processing is performed, the optical fiber cable is connected to the measuring device 20 (S11).

  Then, both ends of the optical fiber built-in PC steel material 10 are tensioned with a jack, and the measurement of the strain distribution along the longitudinal direction of the optical fiber is started by the measuring device 20 (S12). The PC 30 acquires data on the strain distribution of the optical fiber from the measuring device 20, and calculates the friction information of the optical fiber built-in PC steel material 10 from the strain distribution (S13).

  As shown in FIG. 5 (a), when the optical fiber built-in PC steel material 10 is in tension, the tension T at both ends of the optical fiber built-in PC steel material 10 and the optical fiber built-in PC steel material 10 are surrounded (girder material 60). The optical fiber built-in PC steel material 10 is distorted according to the frictional force F received from the inner surface of the through-hole of the optical fiber, and the optical fiber of the optical fiber cable 12 (see FIG. 2) is similarly distorted.

  FIG. 5B schematically shows the relationship (strain distribution) between the position and strain along the longitudinal direction of the optical fiber built-in PC steel material 10 having a length L. Since the tension force T and the friction force F are in opposite directions, the friction force F causes a loss of the tension force T (friction loss), and as shown in FIG. ) Is affected by the friction at each position of the optical fiber built-in PC steel 10 and decreases toward the center.

  In the present embodiment, the frictional force F along the longitudinal direction of the optical fiber built-in PC steel 10 is obtained as friction information from the tension T at both ends of the optical fiber built-in PC steel 10 and the strain distribution along the longitudinal direction of the optical fiber. , And by inputting necessary physical property values into the PC 30 in advance, the apparent friction coefficient can be calculated from the distribution of the frictional force F and the physical property values.

  The apparent friction coefficient is, for example, the distribution of the friction coefficient between the optical fiber built-in PC steel 10 and the through hole along the longitudinal direction of the optical fiber built-in PC steel 10 or the deflection location of the optical fiber built-in PC steel 10. It is calculated based on the value at. Based on this friction coefficient, the tension force when prestress is introduced to the girder 60 by the tension of another tension material (not shown) can be determined in consideration of the friction loss. The another tension material may be a normal PC steel stranded wire without the optical fiber cable 12.

  After the tension of the optical fiber built-in type PC steel material 10, both ends of the optical fiber built-in type PC steel material 10 are fixed to the bearing plates at both ends of the beam member 60 by the fixing body. Then, the strain distribution along the longitudinal direction of the optical fiber is measured (S14).

  In S14, for example, the cable 12 is once removed from the measuring device 20, and the cable 12 is peeled off from the optical fiber built-in PC steel material 10 to the position of the fixing body 62 as shown in FIG. Then, as shown in FIG. 6B, the excess length of the optical fiber built-in PC steel material 10 is cut.

  After that, as shown in FIG. 6C, a grout cap 50 for preventing grout leakage is attached so as to cover the end of the optical fiber built-in PC steel material 10 and the fixing member 62. The grout cap 50 is provided with a hole 52 for inserting a cable, and the cable 12 of the optical fiber built-in PC steel material 10 is drawn out through the hole 52 and connected to the measuring device 20 to measure the strain distribution of the optical fiber. To start.

  The PC 30 acquires data on the strain distribution of the optical fiber from the measuring device 20, and calculates temperature information around the optical fiber built-in PC steel 10 from the strain distribution (S15).

  That is, the optical fiber built-in PC steel 10 is distorted according to the ambient temperature, and the optical fiber of the optical fiber cable 12 is similarly distorted. Therefore, the temperature information in the surrounding through-hole 601 is calculated from the strain distribution along the longitudinal direction of the optical fiber. it can.

  In the present embodiment, for example, as shown in FIG. 7A, a relationship R () between an external temperature change Δt and a strain change Δs of the optical fiber of the optical fiber built-in PC steel material 10 in a tension state is obtained by a prior measurement. For example, R = Δt / Δs) is calculated and stored in the storage unit 32 of the PC 30.

In S15, the temporal change in ambient temperature (Δt, see FIG. 7C) using the above relationship R from the temporal change in the strain S of the optical fiber measured by the measuring device 20 (Δs, see FIG. 7B). ) And the ambient temperature t can be obtained as a time change (t ₀ + Δt) from the initial value t ₀ . The initial value t ₀ may be the outside temperature, for example.

  In this embodiment, the strain distribution along the longitudinal direction of the optical fiber is measured continuously, and the temperature distribution in the through-hole 601 along the longitudinal direction of the optical fiber built-in PC steel 10 is obtained as temperature information by the above method. Is calculated over time. Thereby, it can be confirmed whether the temperature distribution in the through-hole 601 satisfies a predetermined management value. FIG. 7D schematically shows the temperature distribution in the through-hole 601 along the longitudinal direction of the optical fiber built-in PC steel material 10 having a length L at a certain point in time.

  Conventionally, it is difficult to continuously and continuously measure and manage the ambient temperature distribution along the longitudinal direction of the optical fiber-embedded PC steel material 10, and the grout material 63 can be frozen during cold weather such as winter. In view of this, the filling operation is avoided in the process, or when it is unavoidable, a heating wire is provided around the sheath tube (through hole 601) to ensure the temperature and the filling is performed.

  In this embodiment, as described above, the temperature distribution along the entire length of the optical fiber built-in PC steel material 10 can be continuously and continuously measured, and the temperature in the through hole 601 can be confirmed and managed. This is also advantageous in terms of quality assurance during grout filling. A heating wire may be provided around the sheath tube to heat the entire length of the optical fiber built-in PC steel material 10. In this case, the heating temperature is controlled based on the measured value of the strain distribution of the optical fiber. The temperature in the sheath tube can be adjusted so as not to be lower than a control value (for example, 5 ° C. or the like).

  In this way, the temperature in the through hole 601 is controlled, and the grout material 63 is introduced into the through hole 601 from a grout injection hole (not shown) provided in the bearing plate 61 and the like as shown in FIG. Fill (S16).

  Also at this time, the PC 30 obtains the data of the strain distribution of the optical fiber from the measuring device 20, and calculates the temperature information around the optical fiber built-in PC steel material 10 from the strain distribution as in S15 (S17). By measuring the temperature change accompanying the filling and hardening of the grout material 63 using an optical fiber installed on the surface of the optical fiber built-in PC steel material 10, the presence or absence of filling failure of the grout material 63, the filling failure location, etc. It can detect and grasp the filling situation. Conventionally, there has been a technology for measuring the temperature change by wrapping an optical fiber for temperature measurement around the surface of the sheath tube, but in this embodiment, it is possible to measure the temperature change on the surface of the PC steel material. More precise detection is possible.

  After that, the end of the cable 12 is removed from the measuring device 20 and protected by being placed in a switch box (not shown) attached to the beam member 60 or the like, and used for managing the beam member 60 by measuring strain distribution or the like. Can do.

  As described above, in the present embodiment, when the optical fiber built-in PC steel material 10 to which the optical fiber cable 12 is attached is tensioned along the longitudinal direction, the friction that the optical fiber built-in PC steel material 10 receives from the surroundings is the optical fiber assembly. Incorporating optical fiber by measuring the strain distribution along the extension of the optical fiber using the BOTDR, BOCDA, FBG method, etc. Friction information about the friction received by the type PC steel 10 can be obtained.

  In this embodiment, since the strain distribution over the entire length of the optical fiber cable 12 can be measured, more useful friction information considering the friction over the entire length of the optical fiber built-in PC steel material 10 can be obtained, and the tension material can be managed with high accuracy. To help. For example, the friction loss at the time of tension, which has been determined empirically in the past, can be grasped quantitatively from the strain distribution, and it can be made higher by setting the tension of another tension material to allow for the friction loss based on the friction information. Accurate tension management is possible.

  Further, the temperature around the optical fiber built-in PC steel 10 affects the distortion of the optical fiber built-in PC steel 10 and hence the distortion of the optical fiber of the optical fiber cable 12. Information can be obtained in the same way, and the temperature state over the entire length of the optical fiber built-in PC steel 10 can be evaluated, which is also useful for high-precision temperature management and filling management during grout filling. It is also possible to omit the calculation of friction information during tension and perform only the calculation of the temperature information. The measurement of the strain distribution of the optical fiber and the calculation of the temperature information by this may be performed only before or during filling of the grout material 63.

  Further, by passing the end of the cable 12 through the hole 52 of the grout cap 50, the cable 12 can be suitably pulled out from the grout cap 50 and connected to the measuring device 20 or the like. After the strain distribution is measured, the end of the cable 12 can be placed and protected in a switch box provided on the beam member 60, and used for managing the beam member 60 by measuring the strain distribution or the like.

  However, the present invention is not limited to this. For example, in the present embodiment, the strain distribution of the optical fiber was measured when the optical fiber built-in PC steel 10 that is the tension material of the present installation was tensioned, but the test tension using the optical fiber built-in PC steel 10 was performed, Alternatively, the above processing may be performed to obtain friction information, which may be used for setting the tension of another tension member of the main installation. At the time of test tension, only the tension of the optical fiber built-in PC steel 10 needs to be performed, and fixing or the like is not necessary.

  In this embodiment, the strain distribution is measured when one optical fiber built-in PC steel 10 is in tension, but the same measurement is performed on a plurality of optical fiber built-in PC steel 10 and each optical fiber built-in PC steel 10 is measured. You may obtain | require the average value etc. of the friction information calculated about the steel materials 10, and may use it for management.

  Further, in this embodiment, prestress is introduced into the girder 60, but the method of the present invention can also be applied at the time of introducing prestress to other structures, such as friction information at the time of tension and before / after grout filling. Obtaining temperature information is useful for building high-quality structures through tension management, temperature management, and filling management.

  In addition, the tension management system of the present invention can also be applied to the case where ground reinforcement by a ground anchor is performed as shown in the tension management system 1a of FIG.

  In the example of FIG. 8, an optical fiber built-in PC steel material 10 is placed on the ground 4 in the same manner as a conventional ground anchor, and the ground 4 is reinforced by introducing a compressive force. The optical fiber built-in PC steel 10 is inserted into the hole 41 formed in the ground 4 and fixed at one end to the ground 4 by the fixing portion 13, and the other end is tensioned to fix the ground at the fixing portion 14. After fixing, the inside of the hole 41 is filled with a grout material 42 (filler) and integrated with the ground 4.

  Thus, even when the optical fiber built-in PC steel 10 is used as a ground anchor, calculation of friction information at the time of tension and temperature information at the time of filling before / after filling is calculated from the strain distribution of the optical fiber by the same tension management method as described above. It can be performed and the same effect can be obtained.

[Second Embodiment]
FIG. 9A shows a tension management system 1 ′ according to the second embodiment. The second embodiment is an example in which an optical fiber built-in PC steel material 10 ′ is used as an outer cable of the beam member 60 ′. In this embodiment, a protruding portion 65 is provided on the beam member 60 ′, and prestress is introduced into the protruding portion 65 through the optical fiber built-in PC steel material 10 ′. About the structure of the tension | tensile_strength management part 2, it is as substantially the same as 1st Embodiment.

  FIG. 9B shows a cross section in a direction perpendicular to the longitudinal direction of the optical fiber built-in PC steel material 10 '. In this example, the PC steel wire 11 and the cable 12 are accommodated in an outer tube 15 such as a PE (polyethylene) tube except for both ends of the optical fiber built-in PC steel material 10 '. The outer tube 15 is filled with an anticorrosive material 16 such as grease. In some cases, anti-corrosion coating is applied to the PC steel wire 11 or the like. With these configurations, when the optical fiber built-in PC steel material 10 'is used as an outer cable, the corrosion of the PC steel wire 11 is prevented.

  Next, a tension management method according to the present embodiment will be described with reference to FIG. FIG. 10 is a flowchart showing a tension management method.

  In this embodiment, the calculation section of the friction information in the optical fiber built-in PC steel material 10 ′ is determined in advance, and the end of the optical fiber cable 12 outside the calculation section is first peeled to the end of the calculation section, and terminal processing is performed. (S21). In the section where the cable 12 is peeled off, the outer tube 15 or the like may be omitted in advance, or the cable 12 may be peeled after the outer tube 15 or the like is removed. Where the cable 12 is peeled off, the outer tube 15 or the like is recoated as necessary, or the grout or the like is filled around after tension to ensure durability.

  Next, this optical fiber built-in PC steel material 10 'is placed through the hole of the overhanging portion 65 of the beam member 60', and the end of the cable 12 is connected to the measuring device 20 (S22).

  Then, both ends of the optical fiber built-in PC steel material 10 'are tensioned with a tensioning jack and measurement of the strain distribution along the longitudinal direction of the optical fiber is started by the measuring device 20 (S23). The PC 30 acquires data on the strain distribution of the optical fiber from the measuring device 20, and calculates friction information from the strain distribution in the same manner as described above (S24).

  After tension of the optical fiber built-in PC steel material 10 ′, both ends thereof are fixed by the overhang portions 65. On the other hand, the cable 12 is temporarily removed from the measuring device 20, and its end is placed and protected in a switch box 66 provided in the beam member 60 'as shown in FIG. Can be used to manage the girders 60 '. Also in this embodiment, the same effect as that of the first embodiment can be obtained by calculating the friction information at the time of tension of the optical fiber built-in PC steel material 10 ′ from the strain distribution of the optical fiber.

  The preferred embodiments of the present invention have been described above with reference to the accompanying drawings, but the present invention is not limited to such examples. It will be apparent to those skilled in the art that various changes or modifications can be conceived within the scope of the technical idea disclosed in the present application, and these are naturally within the technical scope of the present invention. Understood.

1, 1 ', 1a; tension management system 2; tension management unit 4; ground 10, 10'; optical fiber built-in PC steel 11; PC steel wire 12; optical fiber cable 13; fixing unit 14; fixing unit 15; 16; Anticorrosion material 20; Measuring device 30; PC
41; holes 42, 63; grout material 50; grout cap 52; holes 60, 60 '; girders 61; bearing plate 62; fixing member 65; overhanging portion 66; switch box 601;

Claims (9)

An optical fiber cable attached along the longitudinal direction of the tendon,
A strain distribution measuring device for measuring strain distribution along the longitudinal direction of the optical fiber of the optical fiber cable;
A friction information calculation device that calculates friction information related to friction received by the tendon from the strain distribution during tension of the tendon;
A tension management system characterized by including:   The tension management system according to claim 2, wherein the tension material prestresses the structure by tension.   The apparatus further includes a temperature information calculation device that calculates temperature information related to a temperature around the tendon from at least one of the strain distribution before and at the time of filling the filler around the tendon. The tension management system according to claim 1 or claim 2. At the time of tension of the tension material attached along the longitudinal direction of the optical fiber cable, the strain distribution along the longitudinal direction of the optical fiber of the optical fiber cable is measured by the strain distribution measuring device,
A tension management method comprising: calculating friction information on friction received by the tendon from the strain distribution when the tendon is tensioned by a friction information calculating device.   The tension management method according to claim 4, wherein the tension of another tension material is performed with a tension force determined based on the friction information.   The tension management method according to claim 4, wherein the tension material applies prestress to the structure by tension.   The tension management according to claim 6, wherein after measuring the strain distribution, an end of the optical fiber cable is detached from the strain distribution measuring device and placed in a switch box provided in the structure. Method. Before or at the time of filling the filler around the tendon, measure the strain distribution along the longitudinal direction of the optical fiber of the optical fiber cable by the strain distribution measuring device,
The temperature information related to the temperature around the tendon is calculated from the strain distribution at least one of before and during the filling with the temperature information calculating device. The tension management method according to any one of the above.   The fiber optic cable is passed through a hole in the grout cap when the grout cap is attached to the end of the tendon after the tension member is tensioned. Tension management method.

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