JP2019203332A - Pre-grout pc steel, and monitoring device and monitoring method using pre-grout pc steel - Google Patents

Abstract

To exactly detect curing state of a pre-grout resin in constructing a pre-grout PC steel.SOLUTION: A pre-grout PC steel applied to a pre-stressed concrete structure comprises: a PC steel wire (a PC steel wire strand 110 or a PC steel wire 310) to which tensioning force is applied; a coating material (a coating material 130 with rib or a coating material 230 without a rib) coating the PC steel wire; an ordinary temperature curing pre-grout resin 120 filled into a gap between the PC steel wire and the coating material in an uncured state and being cured after the PC steel wire is tensioned; and an optical fiber 150 which is parallel to a longer direction of the PC steel wire, is not twisted, is not in contact with the PC steel wire, is not accompanied with an adhesive, and is buried in the pre-grout resin 120.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a pre-grown PC steel material used for a prestressed concrete (PC) structure, and in particular, a PC steel wire, a covering material covering the PC steel wire, and a gap between the PC steel wire and the covering material. The present invention relates to a pre-grout PC steel material including a room temperature-curing pre-grout resin that is hardened after a PC steel wire is tensioned and filled. Moreover, this invention relates to the monitoring apparatus and monitoring method which monitor the various states of a pre-grouting PC steel material using this pre-grouting PC steel material. In the present invention, the PC steel wire includes a PC steel strand, a PC steel wire, and a PC steel rod.

  In bridges and the like, prestressed concrete girders (prestressed concrete structures) using a post-tension method are often used. In a prestressed concrete structure using such a post-tension method, a polyethylene (resin) or metal sheath is placed before placing the concrete, and the concrete cable is placed in the sheath after placing the concrete. (PC steel wire) is inserted, and after the concrete strength reaches the specified strength, the assembly cable is tensioned and fixed. Finally, the assembly cable is rust-proofed and the assembly cable and concrete are bonded and integrated. For this purpose, cement milk or the like (a resin compound sometimes called grout) is injected between the assembly cable and the sheath. In this case, the arrangement of the sheath, the insertion of the assembly cable into the sheath, and the grout injection operation are very complicated operations and require a lot of labor and time.

  Japanese Patent No. 2559802 (Patent Document 1) discloses a tensioning cable that solves such a problem. This tensioning cable is a tensioning cable used as a tensioning material in which a cable using a plurality of steel wires, steel strands, steel bars, etc. is inserted into or covered with a sheath formed of resin, metal, etc. However, until this tension material is tensioned, it does not cure and is fluid, and a curing agent is added at a blending ratio according to the required curing time so as to cure at room temperature after tension, and curing is started. It is characterized in that a gap between the cable and the sheath is filled with a resin compound having a rust prevention ability for the steel material.

  When the tension cable disclosed in Patent Document 1 is applied to a prestressed concrete structure, sheath reinforcement, cable insertion, and grout injection work performed by the post-tension method are not required. Labor saving and construction period can be shortened. In addition, the resin compound used in the cable is fluid before it hardens and has the property of hardening over time. After being obtained, the PC steel wire can be tensioned, and then the resin hardens, so that adhesion is obtained between the PC steel wire and the concrete, so the same properties as the concrete structure by the conventional post-tension method Can be expressed. In particular, since no heating or artificial means are used to cure the resin, there is no danger of equipment and labor for curing.

Japanese Patent No. 2559802

As described above, according to the tension cable disclosed in Patent Document 1, since heating and artificial means are not used to cure the resin, there is no need for a device for curing, no trouble, and no danger. Has advantages.
By the way, regarding the resin compound of the tension cable disclosed in Patent Document 1, in Patent Document 1, the required number of days until the resin is cured can be freely set by adjusting the amount of the curing accelerator. However, it does not describe actually detecting the cured state in the process of curing the resin.

  Even though the curing state of the resin can theoretically be analyzed, in order to actually determine the curing state of the resin during actual construction, a part of the prestressed concrete structure is destroyed and the tension cable is It is necessary to remove the sheath to expose the resin. If this work is carried out, (1) even if it is a part, it is impossible to return the prestressing force at the broken part, and (2) it is necessary to perform a reliable rust prevention treatment at the time of restoration of the covering removal part. Due to the fact that it is not practical, it is virtually impossible to detect the cured state of the resin. On the other hand, since the cured state of the resin affects the strength of the prestressed concrete structure, it is significant to detect the cured state of the resin.

  The present invention has been developed in view of such significance, and the object of the present invention is to provide a PC steel wire and a covering material for covering it when a prestressed concrete structure is constructed by a post-tension method. Accurately detecting the curing state of the pre-grout resin in the pre-grout PC steel material including the room temperature-curing pre-grout resin that is filled in the gap between the PC steel wire and the coating material in an uncured state and is cured after the PC steel wire is tensioned It is to provide a pre-grout PC steel that can be manufactured at low cost. Furthermore, the objective of this invention is providing the monitoring apparatus and monitoring method which monitor the various states of a pre-grouting PC steel material using this pre-grouting PC steel material.

In order to achieve the above object, a pre-grout PC steel material according to an aspect of the present invention takes the following technical means.
That is, the pre-grouting PC steel according to the present invention is a pre-grouting PC steel applied to a prestressed concrete structure, and includes a PC steel wire to which tension is applied, a covering material that covers the PC steel wire, and the PC The gap between the steel wire and the coating material is filled in an uncured state, and is preheated at room temperature and is cured after the PC steel wire is tensioned, and twisted parallel to the longitudinal direction of the PC steel wire And an optical fiber embedded in the pre-grout resin without contacting the PC steel wire.

Preferably, the covering material includes a rib that forms a space protruding from the outer surface of the covering material in a direction from the center of the PC steel wire to the covering material side when viewed from a cross section perpendicular to the longitudinal direction. The optical fiber can be configured to be embedded in the pre-grout resin filled in the rib.
More preferably, the optical fiber can be configured to be embedded in the pregrout resin without an adhesive.

A monitoring device according to another aspect of the present invention employs the following technical means.
That is, the monitoring device according to the present invention is a monitoring device that monitors various states of the pre-grout PC steel using any of the pre-grout PC steel described above, and transmits an optical signal to the optical fiber. An optical signal receiving unit that receives an optical signal from the optical fiber, and an acquisition unit that acquires the cured state of the pre-grout resin by analyzing the optical signal received by the optical signal receiving unit. .

Preferably, the monitoring device may be configured to further include a determination unit that determines completion of curing of the pregrout resin.
More preferably, the monitoring device further includes a detection unit that detects an abnormality that has occurred in the pre-grouting PC steel material or an abnormality that has occurred in a prestressed concrete structure to which the pre-grouting PC steel material has been applied after the pre-grout resin has been cured. It can be constituted as follows.

A monitoring method according to still another aspect of the present invention employs the following technical means.
That is, the monitoring method according to the present invention uses any of the above-described pre-grout PC steel materials, a cured state of the pre-grouting resin, an abnormal state generated in the pre-grouting PC steel material, or a pre-stressed concrete structure to which the pre-grouting PC steel material is applied. A monitoring method for detecting an abnormal state occurring in an object, wherein the optical signal is transmitted to the optical fiber and received from the optical fiber after the PC steel wire is tensioned and after the pregrout resin is cured. An acquisition step of acquiring a cured state of the pregrout resin by analyzing an optical signal, and a determination step of determining the completion of the curing of the pregrout resin based on the cured state of the pregrout resin acquired in the acquisition step; Curing is completed by the determination step. After being determined, an optical signal is transmitted to the optical fiber and an optical signal received from the optical fiber is analyzed, whereby an abnormal state generated in the pregrout PC steel material or a prestressed concrete structure to which the pregrout PC steel material is applied And a detecting step for detecting an abnormal state occurring in the object.

  According to the pre-grout PC steel material according to the present invention, when a prestressed concrete structure is constructed by the post-tension method, the space between the PC steel wire and the covering material covering the PC steel wire and the PC steel wire and the covering material is filled in an uncured state. It is possible to provide a pre-grout PC steel that can be manufactured at low cost and can accurately detect the curing state of the pre-grout resin in the pre-grout PC steel including the room temperature-curable pre-grout resin that hardens after the PC steel wire is strained. it can. Furthermore, it is possible to provide a monitoring device and a monitoring method for monitoring various states of the pre-grout PC steel material using the pre-grout PC steel material.

It is sectional drawing for demonstrating the structure of the pre-grouting PC steel material which concerns on embodiment of this invention. It is a figure for demonstrating the monitoring state using the pre grout PC steel material shown in FIG.

DESCRIPTION OF EMBODIMENTS Hereinafter, a pre-grout PC steel material according to an embodiment of the present invention, a monitoring device and a monitoring method using the pre-grout PC steel material will be described with reference to the drawings.
[Structure of pre-grout PC steel]
The structure of the pre-grout PC steel material according to the present embodiment will be described with reference to FIG. 1 (A) to FIG. In addition, this pre-grout PC steel material is a PC steel wire. Various PC steel wires with different wire diameters, wire diameters, etc. This includes various types of PC steel bars with different rod diameters.

  1 (A) and 1 (B) are a pre-grout PC steel material 100 and a pre-grouting PC steel material 200 using a PC steel wire 110 as a PC steel wire, and FIGS. 1 (C) and 1 (D) are PCs. A pre-grouting PC steel material 300 and a pre-grouting PC steel material 400 adopting a PC steel wire or a PC steel rod (hereinafter, represented by a PC steel wire 310 as a representative) composed of one strand as a steel wire. 1 (A) and 1 (C) are a pre-grout PC steel material 100 and a pre-grouting PC steel material 300 employing a ribbed coating material 130 having ribs 140 as a coating material for coating a PC steel wire, and FIG. (B) and FIG. 1 (D) are a pre-grout PC steel material 200 and a pre-grout PC steel material 400 that employ a ribless coating material 230 having no ribs as a coating material for coating a PC steel wire. 1 (A) to 1 (D) are cross-sectional views perpendicular to the longitudinal direction of the PC steel wire (the same as the longitudinal direction of the pre-grout PC steel material), and when end treatment is performed. It is the same sectional view except for both ends. In addition, in FIGS. 1A to 1D, the same reference numerals are given to the same components, and redundant description will not be repeated.

  As shown in FIG. 1 (A) to FIG. 1 (D), the pre-grout PC steel material 100 (covered with ribs, PC steel strand), the pre-grout PC steel material 200 (cover without ribs, PC steel strand) according to the present embodiment ), Pre-grout PC steel 300 (coated with ribs, PC steel wire), pre-grout PC steel 400 (coated without ribs, PC steel wire) is a pre-grout PC steel applied to prestressed concrete and is given tension. PC steel wire (PC steel strand 110 or PC steel wire 310), a covering material covering the PC steel wire (a covering material 130 with ribs or a covering material 230 without ribs), and a gap between the PC steel wire and the covering material And a room temperature curable pregrout resin 120 that is filled in an uncured state and hardens after the PC steel wire is tensioned.

As a characteristic structure of these pre-grout PC steel materials, it is parallel to the longitudinal direction of this PC steel wire, and is not twisted and may be described as a pre-grout resin (post-cured resin or epoxy resin) without contacting with the PC steel wire. ) Including an optical fiber 150 embedded in 120.
Here, except for this characteristic structure, these pre-grout PC steel materials 100, 200, 300, and 400 are known pre-grout PC steel materials disclosed in Patent Document 1 described above, and are room temperature-curable pre-grouting resins. 120 is a PC steel wire that is applied to the surface of a PC steel wire in an uncured state and covered with a sheath tube that is a covering material. As an example, an afterbond (registered trademark) PC steel wire manufactured and sold by the applicant is Can be mentioned.

  The optical fiber 150 embedded in the uncured pre-grout resin 120 in such a known pre-grout PC steel material is (1) an optical fiber having a normal structure without a special structure, and (2) a PC steel wire. It is embedded without contacting with the PC steel wire without being twisted and parallel to the longitudinal direction (the same as the longitudinal direction of the pre-grout PC steel material). Thus, when embedding the optical fiber 150 in the pre-grout resin 120, it is not necessary to use an optical fiber having a special structure (to make contact with the PC steel wire), and it is more in line with the state (to make contact with the PC steel wire). Therefore, it is not necessary to embed the optical fiber in a special form such as twisting, and it is not necessary to embed the optical fiber in a special positional relationship in contact with the PC steel wire (as will be described later, the optical fiber 150). Is embedded in the pre-grout resin 120 filled in an uncured state without an adhesive), the pre-grout PC steel material according to the present embodiment can be manufactured at low cost. The number of embedded optical fibers 150 is not limited to the one illustrated.

  Here, the fact that the PC steel wire is parallel to the longitudinal direction of the PC steel wire and is not twisted means that, when the PC steel wire is a PC steel strand 110, the strain of the PC steel wire is detected by the optical fiber 150, etc. This means that the case where the optical fiber 150 is twisted so as to correspond to the twist (twist or twist) of the PC steel strand 110 to bring it into contact with the PC steel strand 110 is not included. For this reason, except for the case where it is not completely parallel, it does not mean only the case where it is completely parallel, but that it is parallel to the longitudinal direction of the PC steel wire and is buried without being twisted. It is embedded substantially without being twisted substantially "parallel" to the longitudinal direction of the line. That is, in the manufacturing process of the pre-grout PC steel material according to the present embodiment, a part of the PC steel wire and the optical fiber 150 may not be parallel to each other, and a part of the optical fiber 150 may be manufactured by being twisted. Absent.

  Furthermore, being buried without contacting with the PC steel wire means that the PC steel wire (PC steel strand, PC steel wire, PC steel rod) is used for the purpose of detecting the strain of the PC steel wire with an optical fiber. This means that the case where the optical fiber 150 is buried by contact is not included. For this reason, except for the case where it is not completely contacted, it does not mean only the case where it is not completely contacted. "I mean buried without contact." That is, in the manufacturing process of the pre-grout PC steel material according to the present embodiment, the PC steel wire and the optical fiber may be manufactured in contact with each other.

  In the pre-grout PC steel material 100 and the pre-grouting PC steel material 300 shown in FIGS. 1 (A) and 1 (C), the ribbed coating material 130 is seen from the cross section perpendicular to the longitudinal direction of the PC steel wire, The rib 140 which comprises the space which protruded from the outer surface of the coating | covering material in the direction to the coating | coated material side is provided. As described above, the optical fiber 150 that is parallel to the longitudinal direction of the PC steel wire and is not twisted and is not contacted with the PC steel wire is embedded in the pregrout resin 120 filled in the rib 140. Yes.

  On the other hand, in the pre-grout PC steel material 200 and the pre-grout PC steel material 400 shown in FIGS. 1 (B) and 1 (D), the ribless covering material 230 does not include such ribs 140. As described above, the optical fiber 150 that is parallel to the longitudinal direction of the PC steel wire and is not twisted and is not contacted with the PC steel wire is coated with the PC steel wire (not a rib because there is no rib). It is embedded in the pre-grout resin 120 filled in an uncured state in the gap with the material rib-less 230.

  In any of the pre-grout PC steel materials 100, 200, 300, and 400 shown in FIGS. 1A to 1D, the optical fiber 150 is filled in an uncured state without an adhesive. 120 is buried. Since this pre-grout resin 120 has a room temperature curing property that hardens after the PC steel wire is tensioned, the optical fiber 150 is hardened after the pre-grout resin 120 is cured even if the optical fiber 150 is embedded without an adhesive. PC steel wire (PC steel strand 110 or PC steel wire 310) including 150, pre-grout resin 120 and coating material (ribbed coating material 130 or non-ribbed coating material 230) are integrated (with prestressed concrete structure). . Therefore, after the pregrout resin 120 is cured without using an adhesive, the PC steel wire (PC steel strand 110 or PC steel wire 310) and the optical fiber 150 (with the prestressed concrete structure) are integrated. The

  The optical fiber 150 is used as a sensor for measuring a pressure change caused by shrinkage due to the curing of the pre-grouting resin until the curing of the pre-grouting resin 120 is completed, and measures a strain change of the PC steel wire after the curing of the pre-grouting resin 120 is completed. It is used as a sensor. The optical fiber 150 is not provided with a special structure for contacting with the PC steel wire, and a known general structure including, for example, a core and a clad can be preferably used.

The number of the optical fibers 150 to be embedded is not limited to the single (one) described above, and a plurality of optical fibers 150 may be used. After the pre-grouting resin 120 is cured and the pressure change until the pre-grouting resin 120 is completely cured. It can be appropriately selected according to the measurement method of strain change.
Until the curing of the pre-grout resin 120 is completed, the pre-grout resin 120 is cured as time elapses from the start of curing due to the room temperature curing property of the pre-grout resin 120, and the pre-grout resin 120 contracts according to this curing. When the pregrout resin 120 contracts, the pressure applied to the optical fiber 150 embedded in the pregrout resin 120 corresponding to the contraction of the pregrout resin 120 changes. Therefore, the pressure (or pressure change) received by the optical fiber 150 can be measured by analyzing the optical signal input to and output from the optical fiber, and the cured state of the pregrout resin 120 can be indirectly measured.

After the pre-grout resin 120 has been cured, it is distorted by an abnormality including expansion and contraction of PC steel wire, PC steel material, or prestressed concrete structure (sometimes collectively referred to as PC steel wire or PC steel material). When this occurs, the optical fiber 150 integrated with the PC steel wire or the like is also distorted corresponding to the deformation of the PC steel wire or the like. Therefore, the strain (or strain change) of the optical fiber 150 can be measured by analyzing the optical signal input to and output from the optical fiber, and the strain (or strain change) of the PC steel wire or the like can be indirectly measured.
[Monitoring device and monitoring method]
A monitoring apparatus and a monitoring method for monitoring various states of the pre-grout PC steel material using the pre-grout PC steel material having the above-described structure will be described in detail below.

  The monitoring device analyzes an optical signal received by the optical signal receiver, an optical signal receiver that transmits an optical signal from the optical fiber 150, an optical signal receiver that receives an optical signal from the optical fiber, and the optical signal receiver. And an acquisition unit that acquires the cured state of the pre-grout resin 120. Further, the monitoring device may include a determination unit that determines completion of curing of the pregrout resin 120. Furthermore, this monitoring apparatus can also include a detection unit that detects an abnormality that has occurred in the pregrouting PC steel material or an abnormality that has occurred in the prestressed concrete structure to which the pregrouting PC steel material has been applied after the curing of the pregrouting resin 120 is completed.

An example of the monitoring apparatus according to the embodiment of the present invention will be described in detail below.
This monitoring device is a type of measuring device that inputs and outputs laser light from both ends of the optical fiber 150. Note that a measuring device that inputs and outputs laser light from one end of the optical fiber 150 may be used. In any case, by analyzing the pressure distribution and strain distribution in the longitudinal direction of the optical fiber 150 based on the input and output optical signals, the pressure change generated at each position in the longitudinal direction of the pre-grout PC steel material and A change in strain can be detected.

  The monitoring device analyzes the optical signal received by the optical signal receiving unit, the optical signal receiving unit that receives the optical signal from the optical fiber 150, and the optical signal receiving unit that transmits the optical signal to the optical fiber 150. An acquisition unit that acquires a cured state of the pre-grouting resin 120, a determination unit that determines completion of curing of the pre-grouting resin 120, an abnormality that has occurred in the pre-grouting PC steel after the curing of the pre-grouting resin 120, or a pre-stressed to which the pre-grouting PC steel is applied. It includes a detector that detects abnormalities that occur in concrete structures. In addition to the acquisition unit, the determination unit, and the detection unit, the monitoring device includes a display unit that displays a hardened state of the pregrout resin 120 and a strain state of the PC steel material.

The optical signal transmitter and the optical signal receiver may be configured as an integrated measuring device, for example, and the acquisition unit, the determination unit, and the detection unit are realized by an arithmetic device such as a computer and a program executed by the arithmetic device, for example. The display unit may be realized by, for example, a display monitor that displays the calculation result of the calculation device on the screen.
When the acquisition unit, the determination unit, and the detection unit are realized by an arithmetic device and a program executed by the arithmetic device, the acquisition unit, the determination unit, and the detection unit are realized as follows.

The acquisition unit analyzes the optical signal received by the optical signal receiving unit from the start of curing of the pregrout resin 120, and acquires the cured state of the pregrout resin 120 based on a pressure change that changes in response to the shrinkage of the pregrout resin 120. To do.
Based on the cured state of the pre-grout resin 120 acquired by the acquisition unit, for example, the determination unit determines that the pressure change becomes very small when the pressure change per unit time is less than or equal to a threshold value (no further contraction is determined). ) It is determined that the curing of the pregrout resin 120 is completed.

  The detection unit functions in the same manner as the acquisition unit after completion of the curing of the pregrout resin 120, analyzes the optical signal received by the optical signal reception unit, and the optical fiber 150 (with the pregrout resin 120 and the covering material). The strain of the integrated PC steel wire and / or the strain of the prestressed concrete structure to which this pregrout PC steel material integrated with the optical fiber 150 (with the PC steel wire, the pregrout resin 120 and the coating material) is applied. To detect. In this case, the detection unit stores the analysis value of the optical signal when the curing of the pregrout resin 120 is completed as a reference value. For example, when the strain change from the reference value exceeds a threshold value, the pregrout PC steel material Or an abnormality occurring in a prestressed concrete structure to which the pre-grout PC steel material is applied.

  Next, a monitoring method using this monitoring apparatus will be described with reference to FIG. FIG. 2 is a graph showing the change over time of the state quantity at a certain position (one specific position) in the longitudinal direction of the pre-grout PC steel material, with the horizontal axis representing the time axis and the vertical axis representing the curing of the pre-grout resin 120. An analysis value (or a numerical value based on the analysis value) of the optical signal (at a certain position in the longitudinal direction of the pre-grout PC steel material) received by the optical signal receiving unit as a degree (pressure change) or a strain change is shown. The graph shown in FIG. 2 is displayed on, for example, a display monitor that is a display unit. It is also possible to detect the degree of cure (pressure change) of the pre-grouting resin 120 at a plurality of positions in the longitudinal direction of the pre-grout PC steel material or the strain change at the plurality of positions based on the optical signal received by the optical signal receiving unit. It is. In this case, in addition to the presence or absence of hardening abnormality and distortion abnormality, these abnormality occurrence locations can be specified.

  In this monitoring method, after tension of the PC steel wire and after the start of curing of the pre-grouting resin 120 (pre-grouting resin monitoring period after the start of curing t = 0 in FIG. 2), an optical signal is transmitted to the optical fiber 150 to transmit light. By analyzing the optical signal received from the fiber, the acquisition unit acquires the cured state of the pregrout resin 120, and the curing of the pregrout resin 120 is completed based on the cured state of the pregrout resin 120 acquired in the acquisition step. After the determination step determined by the determination unit and the determination step determines that the curing is complete (PC steel wire strain monitoring period after the completion of the curing in FIG. 2), an optical signal is transmitted to the optical fiber and received from the optical fiber. By analyzing the optical signal, the difference generated in the pre-grout PC steel Detector abnormal conditions encountered state or Puregurauto prestressed concrete structure PC steel is applied and a detection step of detecting.

  The configuration and operation of the acquisition unit in the acquisition step until the curing of the pregrout resin 120 is completed and the configuration and operation of the detection unit in the detection step after the curing of the pregrout resin 120 are completed are basically the same. It is possible to monitor the hardened state of the pre-grout resin 120 and the abnormal state generated in the pre-grout PC steel material or the abnormal state generated in the pre-stressed concrete structure to which the pre-grout PC steel material is applied depending on the configuration and operation. This is greatly different from the conventional technique for detecting the light using an optical fiber.

  As described above, according to the pre-grout PC steel material according to the present embodiment, it can be manufactured at a low cost, and when the prestressed concrete structure is constructed by the post-tension method, the PC steel wire, the covering material for covering the PC steel wire, and the PC It is possible to accurately detect the curing state of the pre-grout resin in the pre-grout PC steel material including the room temperature-curing pre-grout resin which is filled in the gap between the steel wire and the coating material in an uncured state and is cured after the PC steel wire is tensioned. it can. Further, according to the monitoring apparatus and monitoring method using the pre-grout PC steel, the pre-grout resin is cured, the abnormal state generated in the pre-grout PC steel, or the abnormal state generated in the pre-stressed concrete structure to which the pre-grout PC steel is applied. Can be detected.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. The scope of the present invention is defined by the terms of the claims, rather than the description above, and is intended to include any modifications within the scope and meaning equivalent to the terms of the claims.

  The present invention is preferable for pre-grout PC steel applied to a prestressed concrete structure and its monitoring technology, and is generated in a pre-stressed concrete structure to which a pre-grout PC steel material is applied, a hardened state of a pre-grout resin, an abnormal state generated in the pre-grouting PC steel. This is particularly preferable in that the abnormal state can be accurately detected.

100 pre-grout PC steel (ribbed coating, PC steel strand)
110 PC steel stranded wire (PC steel wire)
120 Pre-grout resin 150 Optical fiber 200 Pre-grout PC steel (coating without ribs, PC steel strand)
310 PC steel wire, PC steel bar (PC steel wire)
300 Pre-grout PC steel (coated with ribs, PC steel wire)
400 Pre-grout PC steel (Ribless coating, PC steel wire)

Claims (7)

Pre-grout PC steel applied to prestressed concrete structures,
PC steel wire to which tension is applied,
A covering material for covering the PC steel wire;
Room temperature curable pregrout resin that is filled in an uncured state in the gap between the PC steel wire and the coating material and is cured after the PC steel wire is tensioned,
A pre-grout PC steel material including an optical fiber embedded in the pre-grout resin without being in contact with the PC steel wire without being twisted and parallel to the longitudinal direction of the PC steel wire. The covering material includes a rib that configures a space protruding from the outer surface of the covering material in a direction from the PC steel wire center to the covering material side as seen from a cross section perpendicular to the longitudinal direction,
The pre-grouting PC steel material according to claim 1, wherein the optical fiber is embedded in the pre-grouting resin filled in the rib.   The pre-grouting PC steel material according to claim 1 or 2, wherein the optical fiber is embedded in the pre-grouting resin without an adhesive. A pre-grout PC steel material according to any one of claims 1 to 3, wherein the pre-grout PC steel material is a monitoring device that monitors various states of the pre-grouting PC steel material,
An optical signal transmitter for transmitting an optical signal to the optical fiber;
An optical signal receiver for receiving an optical signal from the optical fiber;
A monitoring device comprising: an acquisition unit that acquires the cured state of the pre-grout resin by analyzing the optical signal received by the optical signal reception unit.   The monitoring apparatus according to claim 4, further comprising a determination unit that determines completion of curing of the pregrout resin.   The monitoring device further includes a detection unit that detects an abnormality that has occurred in the pre-grout PC steel material or an abnormality that has occurred in a prestressed concrete structure to which the pre-grouting PC steel material is applied after the completion of the curing of the pre-grouting resin. The monitoring device described in 1. Using the pre-grout PC steel material according to any one of claims 1 to 3, a cured state of the pre-grouting resin, an abnormal state generated in the pre-grouting PC steel material, or a pre-stressed concrete structure to which the pre-grouting PC steel material is applied. A monitoring method for detecting an abnormal state that has occurred,
After the tension of the PC steel wire and after the hardening of the pregrout resin is started, an optical signal is transmitted to the optical fiber and an optical signal received from the optical fiber is analyzed to determine a hardening state of the pregrouting resin. An acquisition step to acquire;
A determination step of determining completion of curing of the pregrout resin based on a cured state of the pregrout resin acquired in the acquisition step;
After determining that the curing is completed by the determination step, an abnormal state generated in the pre-grout PC steel or the pre-grout PC steel by transmitting an optical signal to the optical fiber and analyzing the optical signal received from the optical fiber And a detecting step for detecting an abnormal state occurring in the prestressed concrete structure to which the is applied.

Images