JP2005181109A - Crack-monitoring material and crack-monitoring system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a crack-monitoring material and a crack monitoring system, for economizing the inspection cost, enhancing inspection reliability, facilitating site work execution, and maintaining the detection function over a long period of time. <P>SOLUTION: When a crack C<SB>1</SB>occurs in a steel structure 1, the crack-monitoring material 3 applied to and formed on a surface of the steel structure 1 is partly broken to cause a crack C<SB>1</SB>to occur. The electrical resistance of conductive layers 4a in respective monitored areas A<SB>1</SB>to A<SB>49</SB>is measured by an energized-state measurement part 7. The change in the electrical resistance is evaluated by an evaluation part 9 to specify the monitored area A<SB>1</SB>. When the crack C<SB>1</SB>occurs in the monitored area A<SB>1</SB>, the amount of change of resistance value between electrodes is increased, in a direction crossing the progressing direction of the crack C<SB>1</SB>, in comparison with a change in resistance value between electrodes in the same direction as the developing direction of the crack C<SB>1</SB>. Because of this, the progressing direction of the crack C<SB>1</SB>is specified, when measuring electric resistance between electrodes confronting longitudinally, laterally, and obliquely, in the monitored region A<SB>1</SB>of the conductive layers 41 by the measurement part 7 to evaluate a change in electric resistance by the evaluation part 9. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a crack monitoring material that is formed on the surface of a monitoring object that is predicted to generate cracks and that monitors the crack generated in the monitoring object, and a crack monitoring system that monitors the crack.

  In steel structures, fatigue cracks occur at sites where tensile loads are applied due to repeated loads, and serious conditions such as loosening or dropping of rivets and bolts at joints occur. If such a serious condition grows to a size that affects the proof stress of the structure, the structure will be destroyed. Construction is being done for. The seriousness of steel structures develops over multiple years under normal conditions, so there is no need to repair or reinforce immediately when deformation occurs. Moreover, since the progress may stop in the middle of the deformation, it is necessary to monitor the progress after the occurrence of the deformation in order to determine the necessity of repair or reinforcement.

  Table 1 is an example in the case where repair or reinforcement is required immediately as a serious problem occurring in a steel structure. For example, as shown in Table 1, when the cracks in the main girder flange, stringer, and cross beam tension side flange reach 20 mm, it is immediately determined that repair or reinforcement is necessary. Here, the group shown in Table 1 means the whole rivet or bolt used for one base material constituting the joint. The serious condition is roughly divided into a decrease in joining force due to loosening and breaking of rivets and bolts, a decrease in breaking strength due to fatigue cracking of members, and a decrease in running stability due to displacement of the entire structure due to ground subsidence. Fatigue cracks occur at sites where a tensile force is applied when a repeated load is applied, so the occurrence location can be assumed to some extent depending on the structure type. In addition, it is known that the influence of the generated crack on the structure differs depending on the part.

  For inspection of steel structures, periodic inspections that are conducted within two years, irregular inspections that are performed when a large load is received during an abnormality such as an earthquake, and abnormalities that are assumed by periodic inspections, etc. There are detailed inspections conducted. The periodic inspection and the irregular inspection mainly consist of visual inspection from the inspection passage by patrol, and in this visual inspection, the breakage portion of the anticorrosion coating film is visually observed in the vicinity of the portion where the occurrence of cracks is assumed. The coating film rupture accompanying the occurrence of cracks in the steel material grows linearly from the portion assumed to be the stress concentration portion, and can be easily distinguished from other coating film rupture causes. Moreover, it is known from past experience that the anticorrosion coating film breaks at the time of fatigue cracking of the steel material. Rupture of rivets and bolts can be easily detected using binoculars if the joint can be observed. Looseness of rivets and bolts can be detected by a hammering test in which the rupture state of the coating film around them is closely observed and a change in the hammering sound is confirmed with a hammer or the like. On the other hand, the detailed inspection may involve the construction of a scaffold for the inspection, although it varies depending on the inspection purpose. Deformation is discovered by visual inspection only at the site close to the inspection passage. In many cases, it is necessary to construct a scaffold and observe it closely, but it requires a lot of cost to construct the scaffold. Become. For this reason, except for highly urgent detailed inspections, inspection is carried out by using the coating scaffolding of the repainting work carried out every 10 to 15 years.

  Conventional crack detection methods include crack detection and length measurement methods using an ultrasonic method and a magnetic particle flaw detection method. Although this method can detect extremely small cracks and evaluate the length with high accuracy, it can measure closely after the cracks are detected by conventional visual inspection. And is not necessary for high-precision measurement beyond visual observation. Further, as a conventional crack detection method, there is a method for predicting a fatigue life by monitoring a cyclic stress applied to a steel structure by an element. In this method, it is possible to monitor a cyclic stress applied to an element installed at an appropriate location of a structure and predict a period using a minor rule based on the number of repetitions until the fracture of the steel material used is empirically known. However, this method does not provide information on the determination of crack initiation time and crack growth, and cannot determine whether the structure needs repair or reinforcement. I can't know. Furthermore, as a conventional crack detection method, there is a method of detecting the occurrence and progress of a crack from a change in characteristics such as electrical resistance of a steel structure. In this method, it is possible to monitor the change in the electrical characteristics of the steel structure itself and determine the occurrence of cracks from the change in the resistance value of the steel material. However, with this method, the resistance of the steel material itself is extremely low, so detection is possible with small test pieces and small structures where the path of the applied current is short, but large structures have large current paths, so cracks The amount of decrease in resistance due to this becomes extremely small, and it becomes difficult to effectively detect a change in resistance.

  In recent years, a method has been proposed in which a conductive thin film is arranged in a structure and the crack is detected by breaking the conductive thin film when a crack occurs in the structure. For example, the conventional crack detection material (Prior Art 1) has a base layer formed by applying a waterproof insulating paint to the wall surface of a tunnel, and a surface of the base layer so as to form a linear pattern electric circuit. And a protective layer formed by applying an insulating paint similar to the base layer to the conductive layer and the base layer to cover them (see Patent Document 1). ). In such a conventional crack detection material, if a crack occurs on the wall surface and an abnormality occurs, the periphery of this abnormal part is peeled off, the conductive layer is disconnected, and the conductive layer is in a non-energized state. An abnormal state of the wall surface can be detected by detecting a non-energized state.

Japanese Unexamined Patent Publication No. 2001-201477 (paragraph numbers 0010 to 0015 and FIG. 2)

  Further, the conventional crack detection material (Prior Art 2) includes a dielectric layer attached to a workpiece or a test piece, a resistance layer that is broken when a crack occurs in the dielectric layer, and the resistance layer. And two curved electrodes that are formed on the surface of the layer and allow current to flow through the resistance layer (see Patent Document 2). In such a conventional crack detection material, the electrode layer is formed in a curved shape so as to have a substantially uniform sensitivity with respect to the crack propagation direction. Therefore, the growth of the crack from the change in the resistance value between the two electrodes. Can be evaluated.

Japanese Patent Laid-Open No. 11-094787 (paragraph numbers 0021 to 0048 and FIG. 1)

  In recent years, two environmental changes have occurred in steel structures: extending the coating cycle (repainting cycle) and the appearance of unpainted structures. Due to the introduction of a highly durable coating system, the repainting cycle has been extended to about 30 years, so the inspection period for proximity inspection using a coating scaffold has become longer. In addition, the use of paint scaffolding can no longer be expected due to the absence of painting due to the use of weather-resistant steel. For this reason, there is a problem that due to such changes in the environment, it will be necessary to construct a scaffold only for inspection in the future, and the inspection cost will increase due to the construction of the scaffold.

  Moreover, in the prior art 1, since it is necessary to paint a base layer, a conductive layer, and a protective layer using a masking tape or the like, the work is difficult and troublesome, and the occurrence of a crack can be detected. There is a problem that the growth of can not be evaluated. Furthermore, in the prior art 2, it is necessary to arrange these electrodes so that a crack is generated at the center of the two curved electrodes, and when the crack occurrence location cannot be accurately predicted, before the crack occurs, There is a problem that electrodes cannot be arranged.

  An object of the present invention is to provide a crack monitoring material and a crack monitoring system capable of reducing inspection costs, improving the reliability of inspection, facilitating on-site construction, and maintaining a detection function for a long time.

The present invention solves the above-mentioned problems by the solving means described below.
In addition, although the code | symbol corresponding to embodiment of this invention is attached | subjected and demonstrated, it is not limited to this embodiment.
The invention of claim 1 is a crack monitoring material that is formed on the surface of the monitoring object (1; 15) where the occurrence of cracks (C ₁ ) is predicted, and monitors the cracks generated in the monitoring object, A crack monitoring material (3; 16) comprising a crack detection unit (4; 17) for detecting a position of a crack generated in the monitoring object.

  The invention according to claim 2 is the crack monitoring material according to claim 1, wherein the crack detection portion is formed by applying a paint.

  According to a third aspect of the present invention, in the crack monitoring material according to the first or second aspect, the crack detection unit includes a conductive layer (4a; 17a) whose electric resistance changes according to the progress of the crack, and the And an electrode layer (4c; 17b) for passing a current to the conductive layer, wherein the electrode layer is formed in a plurality of rows and a plurality of columns on the surface of the conductive layer.

  The invention according to claim 4 is the crack monitoring material according to claim 3, wherein a plurality of the electrode layers are formed in each row and / or each column.

According to a fifth aspect of the present invention, in the crack monitoring material according to the third or fourth aspect, the conductive layer is divided into a plurality of monitoring regions (A _{1 to} A ₄₉ ; A ₁ , A ₂ ) by the electrode layer. The crack monitoring material is characterized in that a region surrounded by the adjacent electrode layers forms one monitoring region.

The invention of claim 6 is a crack monitoring system for monitoring a crack (C ₁ ), wherein the crack monitoring material (3; 16) according to any one of claims 3 to 5, and the conductive An energization state measurement unit (7) for measuring the energization state of the layer (S110, S140, S150, S180, S190; S210, S240, S250) and generated on the monitoring object based on the measurement result of the energization state measurement unit It is a crack monitoring system (2) provided with the evaluation part (9) which evaluates the crack to perform (S130, S170, S200; S230).

According to a seventh aspect of the present invention, in the crack monitoring system according to the sixth aspect of the present invention, the energization state measuring unit includes a plurality of monitoring regions (A ₁ ) in which the conductive layer (4a; 17a) is formed by the electrode layer (4c; 17b). To A ₄₉ ; A ₁ , A ₂ ), the energization state is measured for each of the monitoring areas (S110; S210), and the evaluation unit obtains the measurement result of the energization state for each of the monitoring areas. The crack monitoring system is characterized in that the monitoring area (A ₁ ) where the crack has occurred is specified (S130; S230).

  According to an eighth aspect of the present invention, in the crack monitoring system according to the seventh aspect, the evaluation unit specifies the progress direction of the crack based on the measurement result of the energized state in the monitoring region where the crack has occurred (S200). It is the crack monitoring system characterized by doing.

  According to a ninth aspect of the present invention, in the crack monitoring system according to any one of the sixth to eighth aspects, the conductive layer includes a fixed member (13) and a fixing member for fixing the fixed member ( 14) covers the joint (14a) to be joined, and when the crack occurs in the conductive layer, the evaluation unit detects looseness of the fixing member based on the measurement result of the energized state of the conductive layer. (S230) It is a crack detection system characterized by carrying out.

  A tenth aspect of the present invention is the crack monitoring system according to the ninth aspect, wherein the evaluation unit is a measurement result of a conduction state of the conductive layer when the fixed member is fixed by a plurality of the fixing members. The crack monitoring system is characterized in that a loose number of these fixing members is detected based on the above (S270).

  An eleventh aspect of the invention is the crack monitoring system according to any one of the sixth to tenth aspects, wherein the correction unit (10) corrects the measurement result of the energization state measurement unit (S160, S190; S260). ), And the evaluation unit evaluates the crack based on the corrected measurement result (S170, S200; S270).

According to a twelfth aspect of the present invention, in the crack monitoring system according to the eleventh aspect, the energization state measuring unit is configured so that the conductive layer is divided into a plurality of monitoring regions by the electrode layer for each monitoring region. The energization state is measured (S110; S210), and the correction unit measures the energization state of the monitoring region (A _{2 to} A ₄₉ : A ₂ ) where no crack is generated when the conductive portion is cracked. On the basis of the result, the crack monitoring system is characterized in that the measurement result of the energization state of the monitoring region (A ₁ ) where the crack has occurred is corrected (S160; S260).

  According to the present invention, the inspection cost can be reduced, the reliability of the inspection can be improved, the on-site construction is easy, and the detection function can be maintained for a long time.

(First embodiment)
Hereinafter, a first embodiment of the present invention will be described in detail with reference to the drawings.
FIG. 1 is a configuration diagram of a crack monitoring system according to the first embodiment of the present invention.
The steel structure 1 is a fixed structure made of steel. The steel structure 1 is, for example, a bridge that secures a space below a track on which a railway vehicle travels and supports a train load. The crack monitoring system 2 is a system for monitoring a crack C ₁ generated in the steel structure 1. As shown in FIG. 1, the crack monitoring system 2 includes a crack monitoring material 3, a lead wire 5, a power supply unit 6, an energization state measurement unit 7, a control unit 8, an evaluation unit 9, and a correction unit 10. The communication part 11 and the accommodating part 12 are provided. The crack monitoring system 2 is installed at a site of the steel structure 1 where the occurrence of a crack C is predicted.

FIG. 2 is a perspective view showing a part of the crack monitoring material of the crack monitoring system according to the first embodiment of the present invention. FIG. 3 is a plan view of the conductive layer and the electrode layer of the crack monitoring material of the crack monitoring system according to the first embodiment of the present invention. FIG. 4 is a longitudinal sectional view of the crack monitoring material of the crack monitoring system according to the first embodiment of the present invention.
Crack monitoring member 3 is formed on the surface of steel structures 1 cracking C ₁ is predicted, a member for monitoring the crack C ₁ generated in the steel structure 1. As shown in FIGS. 2 to 4, the crack monitoring material 3 includes a crack detection unit 4. As shown in FIG. 1, the crack monitoring material 3 is formed by applying a brush, a roller, a spray, or the like to the surface of the steel structure 1 where the occurrence of a crack C ₁ is predicted.

The crack detection unit 4 is a part for detecting the position of the crack C ₁ generated in the steel structure 1, and as shown in FIGS. 2 and 4, a conductive layer 4a, a rust-proof insulating layer 4b, an electrode layer 4c, An environmental barrier layer 4d and a weather resistant layer 4e are provided. The crack detection unit 4 is made of a coating material that can be expected to have durability over a long period of time, and is formed on the surface of the steel structure 1.

The conductive layer 4a is a coating film whose electrical resistance changes as the crack C progresses. The conductive layer 4a is formed in a planar shape on the surface of the anticorrosive insulation layer 4b of steel structures 1 cracking C ₁ is predicted. As shown in FIG. 3, the conductive layer 4a is divided into a plurality of monitoring areas A ₁ ,..., A ₄₉ by the electrode layer 4c, and the area surrounded by the adjacent electrode layers 4c is one monitoring area A ₁ , A ₂ ,... Are formed. The conductive layer 4a is formed, for example, by applying a conductive paint containing a conductive pigment and an organic resin. The conductive pigment is preferably carbon black, graphite, nickel, copper, silver or the like, and the organic resin is epoxy. Resins, polyurethane resins, acrylic resins, phenol resins, alkyl silicate resins and the like are preferable.

  If the coating thickness of the conductive layer 4a is 10 μm or less, there is a possibility that a continuous coating film cannot be obtained by on-site construction, and if it is 100 μm or more, many coating film defects such as sagging occur when applied. If the viscosity is increased in order to prevent this, workability may be sacrificed. For this reason, the coating thickness of the conductive layer 4a is preferably 10 to 100 μm, and particularly preferably 30 to 60 μm. The physical properties of the coating film of the conductive layer 4a may be cracked by other factors such as expansion and contraction due to a temperature difference of the steel structure 1 when the elongation at break by a tensile test is 10% or less, and at 30% or more, the steel structure 1 The conductive layer 4a may not be destroyed at the same time when cracks occur or when the bolts are loosened. For this reason, as for the physical property of the coating film of the conductive layer 4a, it is preferable that the elongation at the time of the fracture | rupture by a tensile test is 10 to 30%. The conductive layer 4a has a volume resistivity of 1 to 10Ω · cm, and the resistance between the electrodes after coating is adjusted to 200 to 10,000Ω, preferably 200 to 2000Ω, by adjusting the blending amount of the conductive pigment and the organic resin. Is formed. It is preferable to adjust the paint viscosity of the conductive layer 4a to such an extent that it can be applied on site with a brush, roller, spray, or the like.

  The rust prevention insulating layer 4 b is a coating film that electrically insulates the steel structure 1 and the conductive layer 4 a and prevents corrosion of the steel structure 1. As shown in FIGS. 2 and 4, the rust-proof insulating layer 4 b is widely applied and formed on the surface (steel base) of the steel structure 1 so as to include the detection range of the crack C. The anticorrosive insulating layer 4b is an undercoat paint applied to an anticorrosion coating system for steel structures such as an epoxy resin containing an antirust pigment or an organic zinc rich paint. The coating thickness of the rust-proof insulating layer 4b is preferably 30 to 100 μm.

The electrode layer 4c is a coating film that allows current to flow through the conductive layer 4a. The electrode layer 4c is formed in a plurality of rows and a plurality of columns on the surface of the conductive layer 4a, and a plurality of electrode layers 4c are formed in each row and / or each column. A large number of electrode layers 4c are formed on the surface of the conductive layer 4a. For example, as shown in FIG. 3, eight electrode layers 4c are formed at equal intervals in the electrode positions P ₁₁ ,..., P ₁₈ in the first row, and the electrode positions P _{11 ,.} Eight electrode positions P ₁₁ ,..., P ₁₈ are formed at equal intervals, and a total of 64 electrode positions P _{11 ,.} Electrode layer 4c has, for example, defines a conductive layer 4a in the one monitoring the area A ₁ by the electrode position _{P 11, P 12, P 21} , 4 one electrode layer 4c adjacent arranged in P _22, a conductive layer It is divided into a total of 49 pieces of monitoring area a ₁ to a ₄₉ and 4a. The electrode layer 4c is formed by applying the same conductive paint as that of the conductive layer 4a, and the coating thickness, the physical properties of the coating, and the paint viscosity are the same as those of the conductive layer 4a. The electrode layer 4c is preferably formed by adjusting the blending amount of the conductive pigment and the organic resin so that the volume resistivity is 0.01 to 1 Ω · cm.

  The environmental barrier layer 4d is a coating film that protects the conductive layer 4a and the electrode layer 4c and improves the corrosion resistance of the steel structure 1. As shown in FIGS. 2 and 4, the environment blocking layer 4d is applied and formed on these surfaces so as to cover the conductive layer 4a and the electrode layer 4c. The environmental barrier layer 4d is, for example, an intermediate coating applied to an anticorrosion coating system for steel structures such as an epoxy resin coating excellent in environmental barrier properties. The coating thickness of the environmental barrier layer 4d is preferably 60 to 120 μm.

  The weather resistant layer 4e is a coating film that protects the environmental barrier layer 4d from the action of natural factors. The weather resistant layer 4e is formed by applying a weather resistant paint to the surface so as to cover the environmental barrier layer 4d. The weather resistant layer 4e is a top coating applied to an anticorrosion coating system for a steel structure such as a polyurethane resin or a fluorine resin excellent in ultraviolet resistance and chemical resistance.

The lead wire 5 is an electric wire that allows a current to flow through the conductive layer 4a. As shown in FIG. 1, one end of the lead wire 5 is attached and connected to the electrode layer 4c disposed at each electrode position P ₁₁ ,..., P ₈₁ , and the other end is energized. It is connected to the measurement unit 7.

The power supply unit 6 shown in FIG. 1 is a DC power supply or an AC power supply that supplies power to the electrode layer 4c. The power supply unit 6 supplies electric power to the electrode layers 4c arranged at the electrode positions P ₁₁ ,..., P ₈₈ shown in FIG. Power source unit 6 is, for example, supplies power in the monitoring region A ₁ in the row direction (lateral direction) electrode position P ₁₁ opposite to each other with, P ₁₂ and between the electrode positions P _21, arranged in P ₂₂ electrode layer 4c At the same time, power is supplied to the electrode positions P ₁₁ and P ₂₁ and the electrode layers 4 c arranged at the electrode positions P ₁₂ and P ₂₂ facing each other in the column direction (vertical direction) in the monitoring area A ₁ . The power supply unit 6 supplies power to, for example, the electrode positions P ₁₁ and P ₂₂ and the electrode layers 4 c disposed at the electrode positions P ₁₂ and P ₂₁ that are opposed to each other in the oblique direction in the monitoring region A ₁ .

FIG. 5 is a plan view for explaining the measurement operation of the energization state measurement unit of the crack monitoring system according to the first embodiment of the present invention.
The energization state measuring unit 7 is a resistance measuring instrument that measures the energization state of the conductive layer 4a. The energization state measurement unit 7 measures the energization state for each of the monitoring areas A _{1 to} A ₄₉ based on a command from the control unit 8. Energized state measurement unit 7 is connected to the power supply unit 6, the electrode position P ₁₁ of the power from the power supply unit 6, ..., supplied to the electrode layer 4c disposed P _81. For example, as shown in FIG. 5, when the crack C ₁ occurs in the monitoring area A ₁ , the energization state measurement unit 7 measures the electrical resistance of the conductive layer 4 a in the monitoring area A ₁ where the crack C ₁ has occurred. The electrical resistance of at least one of the monitoring areas A ₂ ,..., A _{49 where} the crack C ₁ is not generated is measured.

A control unit 8 shown in FIG. 1 is a central processing unit (CPU) that controls various operations of the crack monitoring system 2. The control unit 8 instructs the power supply unit 6 to supply power, instructs the energization state measurement unit 7 to measure the energization state, or transmits the measurement result of the energization state measurement unit 7 to the correction unit 10 to correct this. or to correct the measurement results in section 10, sends the correction result of the correction unit 10 and transmitted to the evaluation unit 9 or to evaluate the crack C ₁ to the evaluation unit 9, the evaluation results of the evaluation unit 9 from the communication unit 11 I will let you. The control unit 8 is connected to the power supply unit 6, the energization state measurement unit 7, the evaluation unit 9, the correction unit 10, and the communication unit 11.

The evaluation unit 9 is a part that evaluates the crack C ₁ generated in the steel structure 1 based on the measurement result of the energization state measurement unit 7. As shown in FIG. 3, the evaluation unit 9 specifies the monitoring region A ₁ where the crack C ₁ has occurred or determines the size of the crack C ₁ based on the measurement result of the energization state for each of the monitoring regions A _{1 to} A _49. Or evaluate. The evaluation unit 9, for example, to identify the extending direction of the cracks C ₁ based on the measurement result of the current state of the surveillance area A ₁ generated cracks C _1. When the correction unit 10 corrects the measurement result of the energization state measurement unit 7, the evaluation unit 9 evaluates the crack C ₁ based on the corrected measurement result.

The correction unit 10 is a part that corrects the measurement result of the energization state measurement unit 7. The correction unit 10 compensates the measurement result of the energization state measurement unit 7 when it is affected by a change due to the outside air temperature or a characteristic change due to aging. As shown in FIG. 5, when the crack C ₁ occurs in the conductive layer 4a in the monitoring area A ₁ , the correction unit 10 energizes the monitoring areas A ₂ ,..., A ₄₉ where the crack C ₁ does not occur. Based on the measurement result of the state, the measurement result of the energization state of the monitoring area A ₁ where the crack C ₁ has occurred is corrected.

  The communication unit 11 illustrated in FIG. 1 is a part that transmits the evaluation result of the evaluation unit 9. The communication unit 11 transmits the evaluation information output from the control unit 8 to a transceiver in the central monitoring room (not shown) by wire or wirelessly, or receives an evaluation information transmission command from the transceiver in the central monitoring room. Such as a transceiver.

  The accommodating portion 12 is a portion that accommodates the power source portion 6, the energization state measuring portion 7, the control portion 8, the evaluating portion 9, and the correcting portion 10. Lead wires 5 are drawn into the housing portion 12 and are connected to connection terminals (not shown). As shown in FIG. 1, the accommodating portion 12 accommodates the power source portion 6 and the energized state measuring portion 7 in a united state, and is attached and fixed to the surface of the steel structure 1.

Next, a crack monitoring material manufacturing method in the crack monitoring system according to the first embodiment of the present invention will be described.
While cracking C ₁ within a limited range in steel structure 1 is predicted may not be identified the origin of the crack C _1. For example, as shown in FIGS. 1 to 5, when the occurrence of a crack C ₁ is predicted within a limited range of the steel structure 1, the steel including this range when the steel structure 1 is repainted. A rust-proof insulating paint is applied to the surface of the structure 1 to form a rust-proof insulating layer 4b. Next, the conductive layer 4a is formed by coating the surface of the rust-proof insulating layer 4b with a conductive coating material. Thereafter, for example, a film having through holes formed in portions corresponding to the electrode positions P _{11 to} P ₈₈ is attached to the surface of the conductive layer 4a, and a conductive paint is applied from the surface of the film. Then, the film coated with a conductive paint to peel to the surface of the conductive layer 4a from the conductive layer 4a, thereby forming the electrode layer 4c in many point-like on the electrode position P ₁₁ to P _49. Next, the electrode position P ₁₁ to P respectively arranged electrode layer 4c to ₄₉ to connect the lead wire 5 is coated with a coating material having environmental barrier properties to the surface of the conductive layer 4a and the electrode layer 4c in a strip environment The blocking layer 4d is formed. Thereafter, a weather-resistant paint is applied in a planar manner on the surface of the environmental barrier layer 4 d to form the weather-resistant layer 4 e, and the crack monitoring material 3 is formed on the surface of the steel structure 1. Finally, the housing portion 12 is fixed to the surface of the steel structure 1, and the lead wire 5 is connected to the connection terminal of the housing portion 12.

Next, the operation of the crack monitoring system according to the first embodiment of the present invention will be described.
FIG. 6 is a flowchart for explaining the operation of the crack monitoring system according to the first embodiment of the present invention.
In step (hereinafter referred to as S) 100, the power is turned on. When the control unit 8 shown in FIG. 1 instructs the power supply unit 6 to supply power, the power supply unit 6 supplies power to the electrode layers 4c disposed at the electrode positions P _{11 to} P ₈₈ shown in FIG. A current flows through 4a.

In S110, the energized state is measured for each monitoring area A ₁ to A _49. When the control unit 8 shown in FIG. 1 instructs the energization state measurement unit 7 to start the energization state measurement, the energization state measurement unit 7 changes the energization state of the conductive layer 4a for each of the monitoring areas A _{1 to} A ₄₉ shown in FIG. Measure and transmit the measurement result to the control unit 8.

In S120, it is evaluated whether or not the energization state has changed. When the control unit 8 transmits the measurement result of the energization state measurement unit 7 to the evaluation unit 9, the evaluation unit 9 evaluates the change in electrical resistance for each of the monitoring regions A _{1 to} A ₄₉ . As shown in FIG. 5, when a crack C ₁ occurs in the monitoring region A ₁ , the crack monitoring material 3 partially breaks and a crack C ₁ occurs in the crack monitoring material 3, and the electric resistance of the monitoring region A ₁ is increased. The amount of change increases. When the energization state changes, the process proceeds to S130, and when the energization state does not change, the determination is repeated until the energization state changes.

In S130, the crack occurrence region is evaluated. As shown in FIG. 5, when the monitoring area A ₁ of the conductive layer 4a crack C ₁ occurs the crack C ₁ is further growing progress, monitoring the change of the electric resistance in the monitoring area A ₁ region A ₂ ,..., A ₄₉ larger than the amount of change in electrical resistance. Therefore, the electrical resistance of the conductive layer 4a in the surveillance area A ₁ to A ₃ measures current measurement unit 7, respectively, the evaluation unit 9 changes in electrical resistance in each monitoring area A ₁ to A ₄₉ evaluate. As a result, the evaluation unit 9 evaluates that the crack C ₁ has occurred in the monitoring region A ₁ where the change in electrical resistance is the largest, and specifies the generation position of the crack C ₁ .

In S140, the resistance value of the monitoring area A ₂ ,... Where the crack C ₁ is not generated is measured. When the conductive layer 4a and the electrode layer 4c are affected by changes in the outside air temperature or changes in characteristics due to aging, it is necessary to compensate the measurement result of the energization state measurement unit 7. Therefore, as shown in FIG. 5, when the cracks C ₁ occurs in the conductive layer 4a in the surveillance area A _1, the monitoring regions A ₂ other than the monitoring area A _1, ..., at least one electrical Of A ₄₉ The measured value of the resistance is measured by the energization state measurement unit 7 and the measurement result is transmitted to the control unit 8, and the control unit 8 transmits the measurement result to the correction unit 10.

In S150, the resistance value of the monitoring area A ₁ generated cracks C ₁ is measured. The energization state measurement unit 7 measures the resistance value in the monitoring area A ₁ and transmits the measurement result to the control unit 8, and the control unit 8 transmits the measurement result to the correction unit 10.

In S160, the resistance value of the monitoring area A ₁ generated cracks C ₁ is corrected. The correction unit 10 calculates the amount of change from the initial value of the measured value of at least one of the monitored areas A ₂ ,..., A ₄₉ (the change in the outside air temperature or the influence value due to aging). As a result, the correction unit 10 subtracts the amount of change from the measured value of the electrical resistance in the monitoring area A ₁ to compensate for changes in temperature and material. When the correction unit 10 transmits the corrected measurement result to the control unit 8, the control unit 8 transmits the corrected measurement result to the evaluation unit 9.

In S170, the crack length is evaluated. The evaluation unit 9 evaluates the actual length of the crack C ₁ that is not affected by changes in the outside air temperature or changes over time, based on the amount of change in the resistance value after correction corrected by the correction unit 10.

In S180, among the vertical, horizontal, and diagonal directions of the monitoring area A ₁ generated cracks C ₁ electrode resistance is measured. The energization state measuring unit 7 measures the electrical resistance between the electrode positions P ₁₁ and P ₁₂ and the electrode positions P ₂₁ and P ₂₂ facing each other in the horizontal direction (row direction) in the monitoring area A ₁ . Further, the energization state measuring unit 7 measures the electrical resistance between the electrode positions P ₁₁ and P ₂₁ and the electrode positions P ₁₂ and P ₂₂ facing each other in the vertical direction (column direction) in the monitoring area A ₁ . Further, the energization state measuring unit 7 measures the electrical resistance between the electrode positions P ₁₁ and P ₂₂ and the electrode positions P ₁₂ and P ₂₁ facing each other in the oblique direction in the monitoring region A ₁ . When the energization state measurement unit 7 measures these electrical resistances and transmits the measurement results to the control unit 8, the control unit 8 transmits the measurement results to the correction unit 10.

In S190, among the vertical, horizontal, and diagonal directions of the monitoring area A ₁ generated cracks C ₁ electrode resistance is corrected. The correction unit 10 subtracts the amount of change from the initial value of the measured value of at least one of the electric resistances in the monitoring area A ₂ ,..., A ₄₉ from the measured value of the inter-electrode resistance in the vertical and horizontal directions in the monitoring area A ₁ . To correct. When the correction unit 10 transmits the corrected measurement result to the control unit 8, the control unit 8 transmits the corrected measurement result to the evaluation unit 9.

In S200, the crack propagation direction is evaluated. In general, when a crack C ₁ occurs between the electrodes, a change in electrical properties in progress in the same direction as the direction of the crack C ₁ is small, the change in the electrical characteristics is large in the direction perpendicular to the extending direction of cracks C _1. For example, when the crack C ₁ occurs in the direction as shown in FIG. 5, the electrical resistance between the electrode positions P ₁₁ and P ₂₁ and the electrode positions P ₁₂ and P _{22 in the} same direction as the direction of propagation of the crack C _1. Change is small, and the change in electrical resistance between the electrode positions P ₁₁ and P _{12 and} between the electrode positions P ₂₁ and P ₂₂ in the direction intersecting with the propagation direction of the crack C ₁ is large. Therefore, based on the generated monitoring area A ₁ of the vertical, horizontal, and diagonal directions of the inter-electrode resistance measurement results of the crack C _1, the evaluation unit 9 to an extending direction of cracks C ₁ evaluates.

In S210, the evaluation result is transmitted. When the evaluation unit 9 transmits the generation position, the crack length, and the crack propagation direction of the crack C _{1 to} the control unit 8 as evaluation information, the control unit 8 transmits the evaluation information to the communication unit 11 and sends it to the central monitoring room (not shown). The communication unit 11 transmits this evaluation information.

In S220, whether the crack C ₁ has reached evaluates to acceptable crack length. For example, as shown in Table 1, when a crack C ₁ occurs in the lower flange, the steel structure 1 immediately needs to be reinforced when the crack C ₁ reaches an allowable crack length of 20 mm. . For this reason, the evaluation unit 9 evaluates whether or not the crack C ₁ has reached the allowable crack length based on the measurement result of the energization state measurement unit 7. Acceptable crack length proceeds to S230 when the cracks C ₁ has reached, repeating the measurement of the current state in each monitoring area A ₁ to A ₄₉ returns to S110 when the crack C ₁ to acceptable crack length is not reached.

  In S230, the evaluation result is transmitted. When the evaluation unit 9 transmits the evaluation result that the steel structure 1 needs to be immediately reinforced as evaluation information to the control unit 8, the control unit 8 transmits the evaluation information to the communication unit 11 and sends it to the central monitoring room (not shown). The communication unit 11 transmits this evaluation information.

The crack monitoring system and the crack monitoring material according to the first embodiment of the present invention have the following effects.
(1) In the first embodiment, the crack detection unit 4 detects the position of the crack C ₁ generated in the steel structure 1. As a result, when a serious deformation that affects the soundness of the steel structure 1 such as a fatigue crack of the steel structure 1 occurs, the occurrence region of this deformation can be detected, and therefore by visual inspection. Uncertainty can be eliminated.

(2) In the first embodiment, the crack detection unit 4 is formed by applying paint. Therefore, for example, the conductive layer 4a and the electrode layer 4c can be easily formed by applying a conductive paint in accordance with the repainting work of the steel structure 1. As a result, it can be easily constructed outdoors or on site, and it is not necessary to build a scaffold only for inspection, thereby reducing costs.

(3) In the first embodiment, a plurality of rows and columns of electrode layers 4c for passing a current through the conductive layer 4a are formed on the surface of the conductive layer 4a whose electrical resistance changes according to the progress of cracks. As a result, the deformation of the steel structure 1 such as the length of the crack C ₁ and the propagation direction can be detected as a change in electrical resistance from a remote location such as an inspection passage.

(4) In the first embodiment, the electrode layer 4c is formed with a plurality in each row and / or each column, so that the conductive layer 4a cracking C ₁ is predicted a number of fine monitoring area A to be divided into ₁ to a _49, it is possible to detect the occurrence region of the crack C ₁ with high precision, it is possible to detect the length and extending direction of the cracks C ₁ with high accuracy.

(5) In the first embodiment, the conductive layer 4a by the electrode layer 4c are divided into a plurality of monitoring areas A ₁ to A _49, one is a region surrounded by the adjacent electrode layers 4c monitoring area A ₁ Form. As a result, it is possible to easily detect in which monitoring area A _{1 to} A ₄₉ the crack C ₁ has occurred.

(6) In the first embodiment, since the evaluation unit 9 evaluates the crack C ₁ generated in the steel structure 1 based on the measurement result of the energization state measurement unit 7, the steel structure is based on the change in the energization state. It is possible to easily detect the length and direction of the crack C ₁ generated in ₁ .

(7) In the first embodiment, since the evaluation unit 9 identifies the monitoring region A ₁ in which the crack C ₁ has occurred based on the measurement result of the energization state measuring unit 7 for each of the monitoring regions A _{1 to} A ₄₉ , The generation position of C ₁ can be detected.

(8) In the first embodiment, since the evaluation unit 9 specifies the progress direction of the crack C ₁ based on the measurement result of the energization state in the monitoring region A ₁ where the crack C ₁ occurs, the crack C ₁ Growth can be monitored.

(9) In the first embodiment, since the measurement result of the energization state measurement section 7 corrector 10 corrects the evaluation unit 9 evaluates the crack C ₁ based on the corrected measurement results, changes in outside air temperature It is possible to compensate for effects such as changes in characteristics due to aging.

(10) In the first embodiment, when the crack C ₁ occurs in the conductive layer 4a, based on the measurement result of the energization state of the monitoring areas A ₂ ,..., A ₄₉ where the crack C ₁ does not occur, The correction unit 10 corrects the measurement result of the energization state of the monitoring region A _{1 where} the crack C ₁ has occurred. As a result, the measurement value in the monitoring area A ₁ can be corrected in consideration of the outside air temperature and the change in material characteristics included in the electrical characteristics in the monitoring area A ₁ where the crack C ₁ occurs.

(Second Embodiment)
FIG. 7 is a configuration diagram of a crack monitoring system according to the second embodiment of the present invention. FIG. 8 is a longitudinal sectional view of the crack monitoring material of the crack monitoring system according to the second embodiment of the present invention. In the following, the same parts as those shown in FIG.
7 and 8 is a steel plate for a joint that is joined to the side surface of the abutting portion when the steel members constituting the steel structure 1 are abutted and joined to each other. The bolt 14 is a fixing member that fixes the attachment plate 13 to the steel structure 1. For example, as shown in FIG. 7, a total of 21 bolts 14 are arranged over three columns (seven rows and three columns) with seven per column at equal intervals. The peripheral edge portion 14a shown in FIG. 8 is a joint portion where the bolt 14 and the attachment plate 13 are joined, and the edge portion of the seating surface of the bolt 14 and the attachment plate 13 are in contact with each other.

  The rust-proof insulating layer 15 is a layer that electrically insulates the steel structure 1 and the attachment plate 13 from the crack monitoring material 16 and prevents corrosion of the steel structure 1 and the attachment plate 13. The rust-proof insulating layer 15 is the same undercoat paint as the rust-proof insulating layer 4b shown in FIGS. 2 and 4 and has the same coating thickness as the rust-proof insulating layer 4b. The rust-proof insulating layer 15 is formed by being applied to the surfaces of the attachment plate 13 and the bolt 14 and covers the peripheral edge portion 14a.

Crack monitoring material 16 is formed on the surface of the anticorrosive insulation layer 15 which cracking C ₁ is predicted, a member for monitoring the crack C ₁ generated in the anticorrosive insulation layer 15. As shown in FIG. 8, the crack monitoring material 16 includes a crack detection unit 17, which is the same paint as the conductive layer 4a shown in FIGS. The same conductive layer 17a, electrode layer 17b, environmental barrier layer 17c, and weathering layer 17d are provided. The conductive layer 17a is applied and formed on the surface of the anticorrosive insulating layer 15, and covers the peripheral edge portion 14a. Electrode layer 17b, as shown in FIG. 7, which defines a conductive layer 17a to one monitoring area A ₁ by the adjacent six electrode layers 17b. One electrode layer 17b is formed at each of the first row electrode position P _H1 and the second row electrode position P _H1 , and the first column electrode positions P _V11 and P _V21 and the second column electrode position P _V12 , Two _PV22 are formed at equal intervals, and a total of six are formed in two rows and two columns.

Next, the operation of the crack monitoring system according to the second embodiment of the present invention will be described.
FIG. 9 is a flowchart for explaining the operation of the crack monitoring system according to the second embodiment of the present invention. In the following, detailed description of steps for executing the same processing as that shown in FIG. 6 is omitted.
In S200, the power supply unit 6 is turned on. As shown in FIG. 7, the power source 6 supplies power to the electrode layer 4c disposed between the electrode positions P _V11 and P _V12 and the electrode positions P _V21 and P _V22 facing each other in the row direction (lateral direction). The power supply unit 6 supplies power to the electrode layers 4c arranged at the electrode positions P _H1 and P _H2 facing each other in the column direction (vertical direction). The electrode position P _H1, P _V11 to the oblique direction to face each other, the electrode position P _H1, P _V21, electrode position P _H1, P _V12 and electrode position P _H1, the power supply unit to the electrodes disposed layer 4c in such P _V22 6 supplies power.

In S220, the energization state is measured for each of the monitoring areas A ₁ and A ₂ . For example, the energization state measuring unit 7 measures the electrical resistance between the electrode positions P _V11 and P _V12 in the row direction in the monitoring area A ₁ and between the electrode positions P _V21 and P _V22 , and the column direction in the monitoring area A ₁ The energization state measuring unit 7 measures the electrical resistance between the electrode positions P _H1 and P _H2 . Further, for example, between the oblique electrode positions P _H1 and P _V11 in the monitoring area A ₁ , between the electrode positions P _H1 and P _V21, between the electrode positions P _H1 and P _{V12, and} between the electrode positions P _H1 and P _V22 . The energization state measuring unit 7 measures the electrical resistance.

In S230, the loosened part of the bolt 14 is evaluated. As shown in FIGS. 7 and 8, when the bolts 14 are loosened, the coating film on the peripheral portion 14a of these bolts 14 is destroyed. As a result, since the amount of change in the electrical resistance of the monitoring area A ₁ is greater than the amount of change in the electrical resistance of the monitoring area A _2, based on the monitoring area A _1, the energized state of each A ₂ measurements, bolt The evaluation unit 9 identifies the monitoring area A _{1 in} which 14 is loosened and the crack C ₁ is generated.

In S240, the electrical resistance of the monitoring area A ₁ which is not cracking C ₁ is measured, the energized state measuring unit 7 the electrical resistance of the monitoring area A ₂ generated cracks C ₁ is determined in S250. Then, in S260, based on the measurement result of the current state of the surveillance area A ₂ that is not cracking C _1, corrects the correction unit 10 the measurement result of the generated current state of the surveillance area A ₁ of the crack C ₁ Therefore, the effects of changes due to outside air temperature and changes in characteristics over time are compensated.

In S270, the number of loose bolts 14 is evaluated. From monitoring area A ₁ within one bolt 14 measurements energized state when a loose, until the measurement result of the current state when that all bolts 14 in the surveillance area A ₁ is loose, evaluated as reference data The part 9 has memorized. Therefore, on the basis of the measurement result of the current state when the crack C ₁ occurs within the monitoring area A ₁ and the and the reference data, the number of bolts 14 loose in the surveillance area A ₁ evaluation unit 9 identifies .

  In S290, it is evaluated whether or not the allowable number has been reached. As shown in Table 1, when the looseness of the main girder attachment bolt reaches 30% of the group, the steel structure 1 is immediately in a state where reinforcement is required. For example, in the case of a group of bolts having a connecting portion constituted by a number exceeding 20 to 100, 6 to 30 bolts corresponding to 30% are allowed to be loosened. Therefore, whether or not the number of loose bolts 14 has reached the allowable number of 6 corresponding to 30% of the total of 21 bolts 14 shown in FIG. The evaluation unit 9 evaluates.

The second embodiment of the present invention has the following effects in addition to the effects of the first embodiment.
(1) In the second embodiment, the peripheral portion 14a and the conductive layer 4a is covered with the bonding and spliced plate 13 and bolts 14, of the conductive layer 4a when the cracks C ₁ occurs the conductive layer 4a Based on the measurement result of the energized state, the evaluation unit 9 detects looseness of the bolt 14. For this reason, the serious deformation | transformation which influences the soundness of the steel structure 1 like the loosening of the volt | bolt 14 is detectable.

(2) In the second embodiment, when the contact plate 13 is fixed by a plurality of bolts 14, the number of loosened bolts 14 is evaluated based on the measurement result of the energization state of the conductive layer 17a. 9 detects. As a result, it is possible to constantly monitor the deformation of the steel structure 1 and prevent the steel structure 1 from being seriously deformed.

Next, examples of the present invention will be described.
(Resistance measurement experiment)
FIG. 10 is a configuration diagram of a resistance measurement experiment of a crack detection coating film according to an embodiment of the present invention, FIG. 10 (A) is a plan view, and FIG. 10 (B) is a front view.
The crack detection coating film 18 shown in FIG. 10 is a coating film that is applied to a detection target that is predicted to generate cracks and detects a crack in the detection target. The crack detection coating film 18 is formed by coating a crack detection coating on the surface of a 3 mm thick substrate with a length L = 1800 mm and a width W = 900 mm in a thickness of t = 0.06 mm. The electrical resistance changes according to the occurrence of cracks. The crack detection coating film 18 is formed by applying a crack detection paint having a resin / pigment ratio of 500% containing carbon black as a conductive pigment and liquid epoxy as an organic material. The electrode 19 is a portion for passing an electric current through the crack detection coating film 18, and is spaced at a distance of L ₁ = 400 mm from the short side of the crack detection coating film 18 and a distance L ₂ = 225 mm from the long side. It is formed with D ₁ = 225 mm and a lateral distance D ₂ = 500 mm. A crack C was introduced into the center of the crack detection coating film 18 shown in FIG. 10 and the electrical resistance between the electrodes 19 was measured.

FIG. 11 is a graph showing the relationship between the crack length of the crack detection coating film according to the embodiment of the present invention and the amount of increase in the resistance value.
The horizontal axis shown in FIG. 11 is the ratio of the crack length (mm) to the short side length (mm) of the crack detection coating film 18, and the vertical axis is the resistance increase (Ω) between the electrodes. Here, α shown in FIG. 11 is an average value of the resistance increase amount between the electrode positions P _I and P _{i and} between the electrode positions P _III and P _{iii shown} in FIG. β is an average value of the resistance increase amount between the electrode positions P _II and P _i, between the electrode positions P _II and P _iii, between the electrode positions P _I and P _{ii, and} between the electrode positions P _III and P _ii . γ is the average value of the resistance increase between the electrode positions P _I and P _{iii and} between the electrode positions P _III and P _i . As shown in FIG. 11, there is no change in the amount of increase in the resistance value between the electrode positions P _A and P _B facing each other in the same direction as the progress direction of the crack C regardless of the size of the crack C. On the other hand, between the electrode positions P _II and P _ii facing each other in a direction crossing the direction of propagation of the crack C, the resistance change amount increases as the crack C increases. As a result, the generation of the crack C and the length of the crack C are detected by detecting a change in the resistance value between the electrode positions P _II and P _ii arranged in the direction intersecting the propagation direction of the crack C. It is possible to detect the progress direction of the crack C.

(Example 1)
FIG. 12 is a graph showing the relationship between the resin / pigment ratio and the volume resistivity of the crack detection coating material according to Example 1 of the present invention.
The horizontal axis shown in FIG. 12 is the resin / pigment ratio (wt%), and the vertical axis is the volume resistivity (specific resistivity) (Ω · cm). Here, the resin / pigment ratio indicates the ratio of the mass of the resin to the mass of the pigment, and the smaller the value, the smaller the amount of resin. Example 1 includes carbon black (manufactured by Denki Black Co., Ltd., trade name: Denka Black) as a conductive pigment, and a liquid epoxy resin (trade name: Epicron, produced by Dainippon Ink & Chemicals, Inc.) as an organic material. It is a crack detection coating material containing.

  Table 2 shows the measurement results of the volume resistivity of carbon black / liquid epoxy resin. In Example 1, as shown in FIG. 12 and Table 2, when the resin content decreases, the volume resistivity decreases and the conductivity is improved. When the crack detection paint of Example 1 is used as the conductive layer 4a shown in FIGS. 1 to 5 and the conductive layer 17a shown in FIGS. 7 and 8, the volume resistivity is about 1 to 10 Ω · cm. In addition, it is desirable to adjust the mass of the organic resin with respect to the mass of the conductive pigment to about 300 to 700 wt%.

(Example 2)
FIG. 13 is a graph showing the relationship between the resin / pigment ratio and the volume resistivity of the crack detection paint according to Example 2 of the present invention.
The horizontal axis shown in FIG. 13 is the resin / pigment ratio (wt%), and the vertical axis is the volume resistivity (mΩ · cm). Example 2 is for crack detection, which contains nickel powder (reagent manufactured by Kanto Chemical Co., Inc.) as a conductive pigment, and liquid epoxy resin (trade name: Epicron, manufactured by Dainippon Ink & Chemicals, Inc.) as an organic material. It is a paint.

  Table 3 shows the measurement results of the volume resistivity of nickel powder / liquid epoxy resin. In Example 2, as shown in FIG. 13 and Table 3, when the resin content decreases, the volume resistivity decreases and the conductivity improves as in Example 1. When the crack detection paint of Example 2 is used as the electrode layer 4c shown in FIGS. 1 to 5 and the electrode layer 17b shown in FIGS. 7 and 8, the volume resistivity is about 0.01 to 0.04 Ω · cm. Thus, it is desirable to adjust the mass of the organic resin to about 20 to 80 wt% with respect to the mass of the conductive pigment.

(Other embodiments)
The present invention is not limited to the embodiment described above, and various modifications or changes can be made as described below, and these are also within the scope of the present invention.
(1) In this embodiment, the steel structure 1 has been described as an example of the monitoring object, but the present invention can also be applied to other structures such as a concrete structure. Further, in this embodiment, it not has been explained by taking a case in which partition the conductive layer 4a by the electrode layer 4c of 8 rows and 8 columns to 49 of the monitoring area A ₁ to A ₄₉ as an example of limiting same, The conductive layer can be divided into any number of monitoring regions by any number of electrode layers. Furthermore, in this embodiment, the bolt 14 has been described as an example of the fixing member. However, the present invention is not limited to this, and a crack C ₁ is generated in the rust prevention insulating layer 15 due to breakage of other fixing members such as rivets. The present invention can be applied to cases.

(2) In this embodiment, the lead wires 5 are connected to the electrode layers 4c and 17b, but a film formed by patterning the lead wires and electrode layers in advance is pasted on the surfaces of the conductive layers 4a and 17a. In addition, an electrode layer can be formed. Also, in this embodiment, the case where the crack detection coating material is manufactured using a liquid epoxy resin whose resin itself is liquid has been described as an example. However, the solid epoxy which has a higher molecular weight than that of the liquid epoxy resin and is solid at room temperature. It is also possible to produce a crack detection coating material with a resin. Furthermore, in this embodiment, the case where the crack detection coating material is manufactured using nickel powder has been described as an example, but the present invention is not limited to this. For example, even if other metal pigments other than nickel powder whose surface is covered with an oxide can be formed into a conductive coating film by being pulverized in a resin, cracks are caused by such other metal pigments. A detection paint can also be produced.

1 is a configuration diagram of a crack monitoring system according to a first embodiment of the present invention. It is a perspective view which fractures | ruptures and shows a part of crack monitoring material of the crack monitoring system which concerns on 1st Embodiment of this invention. It is a top view of the conductive layer and electrode layer of the crack monitoring material of the crack monitoring system which concerns on 1st Embodiment of this invention. It is a longitudinal cross-sectional view of the crack monitoring material of the crack monitoring system which concerns on 1st Embodiment of this invention. It is a top view for demonstrating the measurement operation | movement of the electricity supply state measurement part of the crack monitoring system which concerns on 1st Embodiment of this invention. It is a flowchart for demonstrating operation | movement of the crack monitoring system which concerns on 1st Embodiment of this invention. It is a block diagram of the crack monitoring system which concerns on 2nd Embodiment of this invention. It is a longitudinal cross-sectional view of the crack monitoring material of the crack monitoring system which concerns on 2nd Embodiment of this invention. It is a flowchart for demonstrating operation | movement of the crack monitoring system which concerns on 2nd Embodiment of this invention. It is a block diagram of the resistance measurement experiment of the coating film for a crack detection which concerns on the Example of this invention, (A) is a top view, (B) is a front view. It is a graph which shows the relationship between the crack length of the coating film for a crack detection which concerns on the Example of this invention, and the increase amount of resistance value. It is a graph which shows the relationship between the resin / pigment ratio and volume resistivity of the crack detection coating material which concerns on Example 1 of this invention. It is a graph which shows the relationship between resin / pigment ratio of the coating material for crack detections based on Example 2 of this invention, and volume resistivity.

Explanation of symbols

1 Steel structure (monitoring object)
DESCRIPTION OF SYMBOLS 2 Crack monitoring system 3 Crack monitoring material 4 Crack detection part 4a Conductive layer 4b Rust prevention insulation layer 4c Electrode layer 4d Environmental barrier layer 4e Weathering layer 5 Lead wire 6 Power supply part 7 Current supply state measurement part 8 Control part 9 Evaluation part 10 Correction part 11 Communication part 12 Housing part 13 Connecting plate (fixed member)
14 Bolt (fixing member)
14a Peripheral part (joint part)
15 Rust prevention insulation layer (monitoring object)
16 Crack monitoring material 17 Crack detection portion 17a Conductive layer 17b Electrode layer 17c Environmental barrier layer 17d Weather resistant layer 18 Crack detection coating film 19 Electrode A _{1 to} A ₄₉ Monitoring area C ₁ crack P _{11 to} P ₈₈ Electrode position P _H1 , P _H2 Electrode position P _V11 , P _V12 , P _V21 , P _H22 Electrode position

Claims (12)

A crack monitoring material that is formed on the surface of a monitoring object that is predicted to generate cracks and that monitors the crack that occurs in the monitoring object,
A crack detection unit for detecting a position of a crack generated in the monitoring object;
Crack monitoring material characterized by In the crack monitoring material according to claim 1,
The crack detection part is formed by applying a paint;
Crack monitoring material characterized by In the crack monitoring material according to claim 1 or claim 2,
The crack detector is
A conductive layer whose electrical resistance changes according to the progress of the crack;
An electrode layer for passing current through the conductive layer;
The electrode layer is formed in a plurality of rows and a plurality of columns on the surface of the conductive layer,
Crack monitoring material characterized by In the crack monitoring material according to claim 3,
A plurality of the electrode layers are formed in each row and / or each column;
Crack monitoring material characterized by In the crack monitoring material according to claim 3 or claim 4,
The conductive layer is partitioned into a plurality of monitoring regions by the electrode layer, and a region surrounded by the adjacent electrode layers forms one monitoring region;
Crack monitoring material characterized by A crack monitoring system for monitoring cracks,
The crack monitoring material according to any one of claims 3 to 5,
An energization state measuring unit for measuring an energization state of the conductive layer;
An evaluation unit for evaluating a crack generated in the monitoring object based on a measurement result of the energization state measurement unit;
Crack monitoring system with. The crack monitoring system according to claim 6,
The energization state measuring unit measures the energization state for each monitoring region when the conductive layer is partitioned into a plurality of monitoring regions by the electrode layer,
The evaluation unit specifies a monitoring region where a crack has occurred based on a measurement result of an energization state for each monitoring region;
A crack monitoring system characterized by. The crack monitoring system according to claim 7, wherein
The evaluation unit specifies the progress direction of the crack based on the measurement result of the energization state in the monitoring region where the crack has occurred;
A crack monitoring system characterized by. In the crack monitoring system according to any one of claims 6 to 8,
The conductive layer covers a bonding portion where a fixed member and a fixing member that fixes the fixed member are bonded,
The evaluation unit detects looseness of the fixing member based on a measurement result of a conduction state of the conductive layer when a crack occurs in the conductive layer;
A crack monitoring system characterized by. The crack monitoring system according to claim 9, wherein
The evaluation unit detects a loose number of these fixing members based on a measurement result of a conduction state of the conductive layer when the fixed member is fixed by a plurality of the fixing members;
A crack detection system featuring. In the crack monitoring system according to any one of claims 6 to 10,
A correction unit for correcting the measurement result of the energization state measurement unit;
The evaluation unit evaluates the crack based on a corrected measurement result;
A crack monitoring system characterized by. The crack monitoring system according to claim 11, wherein
The energization state measuring unit measures the energization state for each monitoring region when the conductive layer is partitioned into a plurality of monitoring regions by the electrode layer,
The correction unit corrects the measurement result of the energization state of the monitoring region where the crack has occurred, based on the measurement result of the energization state of the monitoring region where the crack has not occurred when a crack occurs in the conductive unit. ,
A crack monitoring system characterized by.

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