JP2006337232A - Non-destructive inspection device of concrete structure, and non-destructive inspection method of concrete structure - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a non-destructive inspection device of a concrete structure, capable of continuously inspecting release position or the corrosion state of a metal body, such as a reinforcing rod or a steel frame, even in the case that requires inspection over a long distance and capable of shortening an inspection time. <P>SOLUTION: The non-destructive inspection device of the concrete structure is equipped with an induction heating coil 16 for heating the metal body, such as the reinforcing rod or steel frame in the concrete structure by an eddy current, a heater having an inverter device 17, a thermography for detecting the state of the concrete structure by imaging the surface temperature distribution measured by a measuring instrument 22, such as an infrared camera or the like for measuring the surface temperature distribution of the concrete structure, a coil moving truck 18 for moving the induction heating coil along the concrete structure and a moving truck 23 for a measuring instrument for moving the measuring instrument 22 along the concrete structure. The measuring instrument moving truck 23 is controlled so as to always track the coil moving truck 18, while being delayed by a definite time. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention mainly relates to a non-destructive inspection apparatus for a concrete structure and a non-destructive inspection method for a concrete structure for inspecting a concrete structure having a reinforced structure inside an RC reinforced concrete structure or the like.

  If metal objects such as reinforcing bars or steel frames in a concrete structure are corroded due to the penetration of flying salt, use of sea sand, or the progress of neutralization, the load resistance and durability performance of the structure will be reduced. Corrosion of the reinforcing bars causes the cross-sectional area of the reinforcing bars to expand, which may cause the cover concrete part to float or peel off. It is required to do.

  However, since the state of such a concrete structure cannot be detected from the appearance, for example, as a method for inspecting a concrete structure, for example, there is a nondestructive inspection method for a concrete structure using an infrared thermography device. It's being used.

  The inspection method using this infrared thermography device utilizes the fact that the thermal conductivity changes in the places where cavities and floats occur, thereby causing a temperature difference between that part and other parts, By measuring the surface temperature distribution on the surface of the concrete structure and performing image processing on the surface temperature distribution, it is possible to visually detect the presence or absence of cavities, floats, separation, and the like generated in the concrete structure.

  In addition, in the inspection method using this infrared thermography apparatus, it is common to use solar heat, but in places where it is difficult to be affected by solar heat such as near tunnel tunnels and abutments, a heater or a halogen lamp is used. The concrete structure is artificially heated.

  However, the inspection method using this infrared thermography device can detect the presence and position of cavities, floats, delamination, etc. in the concrete structure, but the position of the reinforcing bar in the concrete structure and its corrosion. The state etc. could not be detected.

  In addition, when a concrete structure is artificially heated, there is a problem that it is difficult to heat the entire concrete structure over a wide range by heating with a heater or a halogen lamp.

  On the other hand, as a method for inspecting corrosion of a metal body such as a reinforcing bar, a natural potential method is known in which an electrode is installed on a reinforcing bar and the natural potential of the reinforcing bar is measured. In this method, a reinforcing bar or a steel frame is known. There is a problem that it is necessary to scrape a part of the concrete structure because it is necessary to install an electrode on a metal body such as, and the measurement accuracy is easily affected by the salt content and temperature of the cover concrete There was a problem.

  Therefore, a new inspection method has been developed to solve the above-described problems (see, for example, Patent Document 1).

In this inspection method, the entire concrete structure is heated by heating a metal body such as a plurality of reinforcing bars arranged vertically and horizontally in the concrete structure, and the surface temperature distribution of the concrete structure is measured by a thermography device, By processing the image, the position of a metal body such as a reinforcing bar and the state of corrosion can be detected.
JP 2003-139731 A

  However, in the prior art as described above, since a measuring instrument such as an infrared camera is fixedly used, it is possible to inspect only within a certain limited range, that is, within the measurement range of the infrared camera. In the case where it is necessary to perform inspection over a long distance as in the above, there is a problem that continuous inspection cannot be performed and much time is spent on the inspection.

  Therefore, in view of the above-mentioned problems of the prior art, the present invention provides a position of peeling or a metal body such as a reinforcing bar or steel frame even when inspection is required over a long distance such as a concrete inner wall surface of a tunnel. An object of the present invention is to provide a non-destructive inspection apparatus for concrete structures and a non-destructive inspection method for concrete structures capable of continuously inspecting the corrosion state of the steel and reducing the inspection time.

  In order to solve the conventional problems as described above and achieve the intended object, an invention according to claim 1 includes an induction heating coil for heating a metal body such as a reinforcing bar or a steel frame in a concrete structure by an eddy current; Imaging a surface temperature distribution measured by a heater having an inverter device for supplying a high-frequency alternating current to the induction heating coil and a measuring instrument such as an infrared camera for measuring the surface temperature distribution of the concrete structure A thermography device that can detect the state of the concrete structure, a moving carriage for the coil that moves the induction heating coil along the concrete structure, and a movement for the measuring instrument that moves the measuring instrument along the concrete structure The measuring instrument carriage is controlled so as to always track the coil movement carriage with a certain delay. Characterized in that it is a non-destructive inspection apparatus of the cleat structure.

  The invention of claim 2 is characterized in that, in addition to the configuration of claim 1, a marking means capable of marking an arbitrary position on the surface of the concrete structure is provided at a rear end portion of the movable carriage for measuring instrument. To do.

  In addition to the configuration of claim 1 or 2, the invention described in claim 3 uses the moving carriage for the coil and the moving carriage for the measuring instrument as a single moving carriage, and supports the induction heating coil at the front end of the moving carriage. The measuring instrument is installed at the rear end.

  The invention according to claim 4 is an induction heating coil for heating a metal body such as a reinforcing bar or steel frame in a concrete structure by eddy current, an inverter device for supplying a high frequency alternating current to the induction heating coil, and the concrete structure A measuring instrument such as an infrared camera for measuring the surface temperature distribution of the object, a thermography device capable of detecting the state of the concrete structure by imaging the surface temperature distribution measured by the measuring instrument, and the induction heating coil. The apparatus includes a moving carriage for a coil that moves along the concrete structure and a moving carriage for a measuring instrument that moves the measuring instrument along the concrete structure, and the induction is performed while heating the metal body. The heating coil is moved from one end side to the other end side of the concrete structure, and the induction heating coil is moved accordingly. The measuring instrument is tracked with a delay of a certain time, and the surface temperature distribution after the elapse of a certain time at the position heated by the induction heating coil is measured, and the work of imaging it is performed from one end side to the other end side of the concrete structure. This is a non-destructive inspection method for a concrete structure in which the state of the concrete structure is detected based on the surface temperature distribution image at each position.

  According to a fifth aspect of the present invention, in addition to the configuration of the fourth aspect, an interval time when the measuring device tracks the induction heating coil is determined based on the cover concrete thickness and the heating temperature.

  The invention according to claim 6, in addition to the configuration of claim 4, divides the temperature distribution image of the surface portion of the concrete structure measured by the measuring device for each moving time of the moving carriage into a plurality of divided images, It forms a temperature distribution image of the surface of the concrete structure for each time after heating by combining the divided images corresponding to the movement times, and detects the state of the concrete structure based on the temperature distribution image To do.

  The invention according to claim 7 is characterized in that, in addition to the configuration of claim 4 or 5, marking is performed on the recognized defective portion of the concrete structure.

  A non-destructive inspection apparatus for a concrete structure according to the present invention includes an induction heating coil that heats a metal body such as a reinforcing bar or steel frame in a concrete structure by an eddy current, and an inverter apparatus that supplies a high-frequency alternating current to the induction heating coil. A thermography device capable of detecting the state of the concrete structure by imaging the surface temperature distribution measured by a measuring instrument such as an infrared camera that measures the surface temperature distribution of the concrete structure; A coil moving carriage for moving the induction heating coil along the concrete structure; and a measuring instrument moving carriage for moving the measuring instrument along the concrete structure, the measuring instrument carriage for the coil It is controlled so that the moving carriage is always tracked with a certain delay, so that the inner wall of the tunnel can be Long test object continuous can be continuously examined.

  By providing a marking means capable of marking an arbitrary position on the surface of the concrete structure at the rear end of the measuring instrument moving carriage, the defective portion can be suitably visualized.

  Control is simplified by combining the moving carriage for coil and the moving carriage for measuring instrument with one moving carriage, supporting the induction heating coil at the front end of the moving carriage, and installing the measuring instrument at the rear end. .

  A nondestructive inspection method for a concrete structure according to the present invention includes an induction heating coil that heats a metal body such as a reinforcing bar or a steel frame in a concrete structure by an eddy current, and an inverter device that supplies a high-frequency alternating current to the induction heating coil. A measuring instrument such as an infrared camera that measures the surface temperature distribution of the concrete structure, and a thermography device that can detect the state of the concrete structure by imaging the surface temperature distribution measured by the measuring instrument, A device including a coil moving carriage for moving the induction heating coil along the concrete structure and a measuring instrument moving carriage for moving the measuring instrument along the concrete structure, and While moving the induction heating coil from one end side to the other end side of the concrete structure, The concrete heating is performed by causing the measuring device to track the induction heating coil with a delay of a predetermined time, measuring a surface temperature distribution after a predetermined time at a position heated by the induction heating coil, and imaging the surface temperature distribution. By repeating the process from one end side to the other end side and detecting the state of the concrete structure based on the surface temperature distribution image at each position, it is possible to suitably inspect a long continuous inspection object such as an inner wall of a tunnel. .

  By determining the interval time when the measuring device tracks the induction heating coil based on the cover concrete thickness and the heating temperature, it is possible to clearly determine whether or not it is sound.

  The temperature distribution image of the concrete structure surface portion measured by the measuring device for each moving time of the moving carriage is divided into a plurality of divided images, and the divided images corresponding to the respective moving times are arranged side by side and synthesized every time after heating. By forming a temperature distribution image of the surface portion of the concrete structure and detecting the state of the concrete structure based on the temperature distribution image, a wide range can be continuously inspected.

  By marking the recognized defective part of the concrete structure, the defective part of the concrete structure can be visualized.

  Next, a nondestructive inspection apparatus for a concrete structure according to the present invention will be described.

  FIG. 1 shows an example of a nondestructive inspection apparatus according to the present invention, and reference numeral 10 in the drawing denotes a concrete structure.

  The concrete structure 10 has a structure such as an RC structure or an SRC structure, and a plurality of metal bodies 12, 12... Such as rebars and steel frames are arranged at intervals in the vertical and horizontal directions, and are continuously inspected like a tunnel inner wall. Has a target part.

  This non-destructive inspection apparatus includes an induction heater for heating the metal bodies 12, 12... Inside the concrete and a thermography apparatus, and heats the concrete structure 10 by heating the metal body 12. By measuring the temperature distribution of the surface portion of the concrete structure 10 and imaging it, the state of the concrete structure 10, that is, the corrosion state of the metal body 12, the state of floating / peeling of the cover concrete, etc. It can be detected.

  The non-destructive inspection apparatus includes a control calculation unit 13 formed of a computer, and the control calculation unit 13 controls the entire apparatus.

  The heater has an induction heating coil 16 and an inverter device 17, and an eddy current is generated in the metal body 12 such as a reinforcing bar by supplying high-frequency alternating current from the inverter device 17 and energizing the induction heating coil 16. This causes the metal body 12 to generate heat.

  The heater, that is, the induction heating coil 16 and the inverter device 17 are mounted on a coil carriage 18 so that the induction heating coil 16 can move along the surface portion of the concrete structure 10.

  The induction heating coil 16 is formed by winding a conductive member in a rectangular shape so that the conductive member such as a copper tube has a portion (parallel portion) arranged in parallel with each other, and the longitudinal direction is oriented vertically. Thus, the coil moving carriage 18 is supported by the fixing means 19 so as to face the surface portion of the concrete structure 10.

  Thus, when the induction heating coil 16 has a parallel portion, when the induction heating coil 16 is disposed sideways with respect to the metal bodies 12, 12... And heated over the plurality of metal bodies 12, 12,. Unlike coils having different coil widths at each position such as an elliptical shape, the coil width, the number of turns, etc. are the same at any position in the parallel portion, so that the metal bodies 12 and 12 can be heated evenly. Unevenness can be eliminated.

  In addition, even when the induction heating coil 16 is arranged vertically with respect to the metal body 12, the portion related to the parallel portion can be heated evenly.

  The inverter device 17 converts a commercial power source and outputs a high-frequency alternating current to the induction heating coil 16.

  The inverter device 17 is controlled by wire or wirelessly with respect to the control calculation unit 13, and the control calculation unit 13 controls the frequency and current value of the alternating current and controls the frequency and current value. Feedback is made to the calculation unit 13.

  An RLC resonance circuit is formed by the capacitor and resistor included in the circuit constituting the inverter device 17 and the induction heating coil 16.

  The thermography apparatus includes a measuring instrument 22 such as an infrared camera, and the control calculation unit 13 functions as an image processing unit to display an image of the temperature distribution on the surface of the concrete structure 10.

  The control calculation unit 13 performs various signal processing on the electrical signal output from the measuring instrument 22, displays the surface temperature of the concrete structure 10 in a color corresponding to the signal, and displays the temperature distribution on the surface of the concrete structure 10 as an image. It is made to display with.

  The measuring instrument 22 and the control calculation unit 13 are mounted on a measuring instrument moving carriage 23 so that the measuring instrument 22 such as an infrared camera can move along the surface of the concrete structure 10.

  In addition, a marking means 24 is mounted on the rear end of the measuring instrument moving carriage 23 so that the defective portion of the concrete structure 10 detected by the thermography device can be marked and the defective portion can be visualized.

  Furthermore, the measuring instrument moving carriage 23 is controlled by the control calculation unit 13 so as to track the coil moving carriage 18 with a delay of a predetermined time, and the coil moving carriage 18 and the measuring instrument moving carriage 23 are always at regular time intervals. It is designed to move around.

  This tracking interval time is determined based on the maximum temperature time in the concrete structure to be inspected by the control calculation unit 13 from the existing data. That is, the tracking interval time is determined so that the position heated by the heater is measured by the measuring device 22 a few minutes before the maximum temperature time.

  The maximum temperature time of the concrete structure is determined based on known data indicating the relationship between the thickness of the cover concrete and the load power applied to the coil and the time until the maximum temperature time of the concrete structure.

  Further, the coil moving carriage 18 and the measuring instrument moving carriage 23 are provided with a thermometer 24 and a wheel encoder 25, and the outside temperature is measured from the thermometer 24, and the moving distance of the moving carriages 18 and 23 is determined by the wheel encoder 25. It comes to measure.

  The nondestructive inspection apparatus configured as described above uniformly moves the metal bodies 12, 12, etc. in the concrete structure 10 by the dielectric heating coil 16 while moving the induction heating coil 16 by the coil moving carriage 18. In addition to heating, the measuring instrument moving carriage 23 is controlled so as to always track the coil moving carriage 18 with a certain time delay from the coil moving carriage 18, and the surface of the concrete structure under the same conditions at any position. The temperature distribution can be measured.

  Therefore, even in a long continuous range such as a concrete inner wall of a tunnel or the like, the state of the concrete structure can be integrally displayed by connecting each temperature distribution image measured separately. By analyzing, it is possible to detect the state of the entire concrete structure 10, that is, the position and corrosion state of the metal body 12 such as a reinforcing bar, the presence or absence of floating / peeling of the cover concrete part, and the position thereof.

  Next, a nondestructive inspection method for a concrete structure using the above-described nondestructive inspection apparatus will be described.

  This nondestructive inspection method measures the concrete surface temperature distribution at the position heated by the induction heating coil after a predetermined time by moving the induction heating coil 16 and the measuring instrument 22 at a predetermined time interval. Defects such as floating and peeling of the concrete structure are determined based on the concrete surface temperature distribution image, and the following procedure is used.

  First, a coil moving carriage 18 is installed in the front part of the surface of the concrete structure 10 to be inspected, and a high frequency alternating current is supplied to the induction heating coil 16 from an inverter device 17 mounted on the moving carriage 18. , 12... Starts heating.

  The heating of the metal bodies 12, 12,... By the induction heating coil 16 supplies a constant power instantaneously while moving the coil moving carriage 18 at a constant speed (about 4 km / h), and the thickness of the cover concrete at that position. And the operation of supplying a high-frequency alternating current to the induction heating coil 16 for a certain period of time based on the thickness of the cover concrete. FIG. 2 shows the state of the coil output at that time.

  That is, the high frequency alternating current AC1 is applied for a moment with the output of the inverter device 17 fixed to a predetermined value, and the frequency is tuned to the most suitable frequency for heating, that is, the resonance frequency, and the resonance frequency is measured. Feedback is sent to the control calculation unit 13.

  At the same time, the distance between the induction heating coil 16 and the concrete surface is measured using a laser distance measurement method, and the data is fed back to the control calculation unit 13.

  The control calculation unit 13 calculates the cover concrete thickness at the measurement position based on the fed back resonance frequency and coil-concrete distance data using the proportional relationship between the change in coil-metal distance and the resonance frequency. To do.

  Then, the control calculation unit 13 controls the inverter device 17 according to the cover concrete thickness, fixes the frequency to the above-described resonance frequency, and outputs a predetermined high-frequency alternating current AC2 corresponding to the cover concrete thickness for a certain period of time. Then, the induction heating coil 16 is energized, and the metal body 12 is heated so as to be raised by 20 ° C. to 30 ° C. from the initial state.

  The high-frequency alternating current AC2 to be output is determined based on the relationship between the cover thickness and the amount of electric power required for the predetermined metal body 12 to reach a certain temperature, obtained in advance by experiments or the like.

  By doing in this way, when the cover concrete thickness is large, the output of the inverter device 17 is large, and when the cover concrete thickness is small, the output of the inverter device 17 is controlled to be small.

  Therefore, by repeating such work every time it moves from one end of the concrete structure 10 to the other end, the metal body 12 can be heated to the same temperature at any position, and the entire metal body 12 can be evenly distributed. Can be heated.

  On the other hand, after a certain period of time (5 to 10 minutes) has passed since the moving cart 18 for coiling starts, the moving cart 23 for the measuring instrument is started and measurement of the surface temperature distribution at each position of the concrete structure is started. .

  Then, the measuring instrument moving carriage 23 always tracks the coil moving carriage 18 with a certain delay, and the measuring instrument 22 measures the surface temperature distribution of each position after a certain period of time after heating.

  The tracking interval time is determined based on the maximum temperature time in the concrete structure to be inspected in advance. That is, the tracking interval time is determined so that the position heated by the heater is measured by the measuring device 22 several minutes before the maximum temperature time.

  The surface temperature distribution at each position is imaged (FIG. 3), and image processing is performed to detect a state of the concrete structure at each position, that is, a defective portion such as floating, peeling, or metal body corrosion.

  Then, the marking unit 24 marks the portion determined as the defect position.

  Such a series of operations are sequentially repeated from one end to the other end of the concrete structure, so that even a long continuous inspection target such as an inner wall surface of a tunnel can be continuously inspected.

  This completes the inspection.

  Next, another embodiment of the nondestructive inspection apparatus according to the present invention will be described. In addition, the same code | symbol is attached | subjected to the part same as the above-mentioned Example, and description is abbreviate | omitted.

  FIG. 4 shows an outline of a second embodiment of the nondestructive inspection apparatus according to the present invention, and reference numeral 10 in the drawing denotes a concrete structure.

  The concrete structure 10 has a structure such as an RC structure and an SRC structure as in the above-described embodiment, and a plurality of metal bodies 12 and 12 such as reinforcing bars are arranged at intervals in the vertical and horizontal directions.

  This nondestructive inspection apparatus has a moving carriage 31 that serves as both a moving carriage for coils and a moving carriage for measuring instruments, and an induction heater, a thermography device, and a control calculation unit 13 (computer) are mounted on the moving carriage 31.

  Moreover, the marking means 33 is also mounted on this nondestructive inspection apparatus.

  In addition, the moving carriage 31 includes a thermometer 35 and a wheel encoder 36, and the outside temperature is measured from the thermometer 35, and the moving distance of the moving carriage 31 is measured by the wheel encoder 36.

  The induction heater includes an induction heating coil 16 and an inverter device 17 that supplies a high-frequency alternating current to the induction heating coil 16, and the inverter device 17 is controlled by the control calculation unit 13, that is, frequency and current output. It is like that.

  The induction heating coil 16 is formed in a shape having portions in which conductive members such as copper pipes are arranged in parallel to each other as in the above-described embodiment, and is vertically directed to the front portion of the movable carriage 31 via the support 37. It is supported by.

  On the other hand, the inverter device 17 is mounted on the loading platform 31 a of the movable carriage 31 together with the computer constituting the control calculation unit 13.

  In addition, an infrared camera 22 of a thermography device is installed at a substantially central portion of the loading platform 31a of the movable carriage 31, and this infrared camera 22 can capture an image within a range (horizontal width of about 4 m) f indicated by a one-dot chain line in the figure. It has become. In addition, the distance between the induction heating coil 16 and the above-mentioned range is about 6 m.

  The marking means 33 includes a marking spray supported on the support column 39 so as to be movable up and down. The marking means 33 controls the vertical movement and the spray liquid discharge amount by the control calculation unit 13, and performs marking 40, 40... By spraying on the defective portion detected by the inspection apparatus.

  The nondestructive inspection apparatus configured in this manner uniformly heats the metal body 12 such as a reinforcing bar in the concrete structure 10 by controlling the inverter output and frequency while moving the induction heating coil 16 at a constant speed. can do.

  Further, the surface temperature distribution of the concrete structure 10 can be visually displayed by image processing, and by analyzing the heat conduction of the image, the state of the concrete structure 10, that is, the position of the metal body 12 such as a reinforcing bar, and the like. Corrosion state, presence or absence of floating / peeling of cover concrete part and its position can be detected.

  Furthermore, the marking means 33 can display a defective portion on the surface of the concrete structure 10.

  Next, a nondestructive inspection method using this nondestructive inspection apparatus will be described.

  In this non-destructive inspection method, the concrete surface temperature distribution at the position heated by the induction heating coil 16 is heated by moving the moving carriage 31 on which the induction heating coil 16 and the measuring instrument 22 are mounted at a predetermined interval. The measurement is performed after a predetermined time, and a defective portion such as a float or peeling of the concrete structure is determined based on the concrete surface temperature distribution image.

  First, the movable carriage 31 is arranged on one end side (initial position) of the concrete structure 10.

  Next, a high-frequency alternating current is supplied to the induction heating coil 16 from the inverter device 17 to heat the metal body 12 such as a reinforcing bar by induction heating, and the mobile carriage 31 is made into a concrete structure at a constant speed, for example, 0.6 m / min. Move along the surface of the object 10.

  At this time, the moving distance is measured by the wheel encoder 36 installed on the wheel portion of the moving carriage 31 and output to the control calculation unit 13 (computer).

  Moreover, the control calculation part 13 performs the operation | work which calculates the cover concrete thickness instantaneously, and controls the inverter apparatus output and frequency based on it, and heats the metal bodies 12, such as a reinforcing bar, and this series during a movement. By repeating this operation, the entire metal body 12 is heated uniformly. The coil output at that time is output similarly to the case shown in FIG.

  In other words, the high-frequency alternating current AC1 is instantaneously output while the output of the inverter device 17 is fixed to a predetermined value, the frequency is tuned to the most suitable frequency for heating, that is, the resonance frequency, the resonance frequency is measured, and the control calculation is performed. Feedback to the unit 13.

  At the same time, the distance between the induction heating coil 16 and the concrete surface is measured using a laser distance measurement method, and the data is fed back to the control calculation unit 13.

  The control calculation unit 13 uses the fact that the coil-metal body distance and the resonance frequency are in a proportional relationship, and calculates the cover concrete thickness at the measurement position based on the fed back resonance frequency and coil-concrete distance data. .

  Then, the control calculation unit 13 controls the inverter device 17 according to the cover concrete thickness, fixes the frequency to the above-described resonance frequency, and outputs a predetermined high-frequency alternating current AC2 corresponding to the cover concrete thickness for a certain period of time. Then, the induction heating coil 16 is energized, and the metal body 12 is heated so as to be raised by 20 ° C. to 30 ° C. from the initial state.

  The high-frequency alternating current to be output is determined based on the relationship between the cover thickness and the amount of electric power required for the predetermined metal body 12 to reach a certain temperature, which is obtained in advance by experiments or the like.

  By doing so, the output of the inverter device 17 is controlled to be small when the cover concrete thickness is large, and the output of the inverter device 17 is controlled to be large when the cover concrete thickness is small.

  Such work is repeated every time the concrete structure 10 is moved from one end to the other end.

  On the other hand, about 10 minutes after the start of the movement, the position of the infrared camera 22 reaches the heating position, and the infrared camera 22 starts to measure the infrared rays emitted from the surface of the concrete structure 10, and every time the moving carriage 31 moves 1 m. Measurement (imaging) by the infrared camera 22 is performed.

  Further, the surface temperature change of the concrete structure 10 is measured in parallel with the photographing by the infrared camera 22, and the temperature peak time is calculated.

  As shown in FIG. 5, the measured surface temperature distribution image data f1, f2,... Are divided into four at predetermined intervals (every 1 m), and are divided into divided images a to d, respectively, and processed as follows. .

  First, when the surface of the concrete structure 10 at each position at each time after 10 minutes from the start of moving the carriage is photographed by the infrared camera 22, images f1, f2,. On the other hand, since the distance between the induction heating coil 16 and the infrared camera 22 is constant, the portion of the divided image a is always in the temperature state after 10 minutes of heating, and similarly, the portion of the divided image b is the temperature after 11 minutes of heating. The temperature state after 12 minutes of heating is photographed in the state, the divided image c portion, and the temperature state after 13 minutes of heating is photographed in the portion of the divided image d.

  Therefore, when the divided images a1 to a3 at the positions after 10 minutes to 13 minutes after passing through the induction heating coil are synthesized, a temperature distribution image ga1 of the surface portion of the concrete structure after 10 minutes of heating at the position x is created.

  Similarly, by combining the divided images b2 to b4, the divided images c3 to c5, and the divided images d4 to d6, the surface temperature distribution images gb1 and gc1 at the position x after 11 minutes, 12 minutes, and 13 minutes after heating, respectively. , Gd1 is created.

  And the state of the concrete structure 10 is test | inspected by image-processing the temperature distribution image 10 minutes after a heating, and the temperature distribution image 13 minutes after a heating (at the time of a temperature peak).

  Based on this image processing, a defective part of the concrete structure 10 at the position x, that is, a corroded portion of the metal body 12, a position of floating / peeling of the concrete, etc. is detected, and the position is marked at the rear end of the movable carriage 31. Marking 40 is made by means 33.

  Thereby, the inspection at the position x is completed.

  Next, the surface of the concrete structure at each position at each time is photographed by the infrared camera 22 while moving the movable carriage 31, and the same operation as described above is repeated, so that the heating after 10 minutes at the position y to the heating 13 is repeated. Minute-minute temperature distribution images ga2 to gd2 are obtained. At this time, since the divided image a4 of the temperature distribution image at the position y is continuous with the divided image a3 of the temperature distribution image at the position x, the temperature distribution image at the position x and the temperature distribution image at the position y are seamlessly connected.

  At this position y, the state of the concrete structure 10 is inspected as in the above-described embodiment.

  By repeating the above operations, the concrete structure 10 having a wide inspection range can be continuously inspected.

  In the above-described embodiment, the example in which the distance from the induction heating coil 16 to the imaging range f of the infrared camera 22 is 6 m and the horizontal width of the imaging range f is 4 m has been described, but this value is 6 m or 4 m, respectively. The value may be any value without being limited to.

  Further, in the above-described embodiment, the method of adjusting the current output and frequency of the inverter device or the current frequency and the coil moving speed at the time of heating the metal body has been described. However, only the coil moving speed is adjusted by making the frequency and current output constant. Alternatively, the current output and the coil moving speed may be constant and only the frequency may be adjusted.

It is the schematic which shows the nondestructive inspection apparatus which concerns on this invention. It is a graph which shows the relationship between an inverter apparatus output and time. It is a surface temperature distribution image several minutes before the temperature peak time. It is a block diagram which shows the outline of other embodiment of the nondestructive inspection apparatus of the concrete structure which concerns on this invention. It is explanatory drawing for demonstrating the image processing method.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Concrete structure 11 Nondestructive inspection apparatus 12 Metal body 13 Control operation part 16 Induction heating coil 17 Inverter apparatus 18 Moving carriage for coils 19 Fixing means 22 Measuring instrument 23 Moving carriage for measuring instruments 24 Marking means 31 Moving carriage 31a Loading bed part 33 Marking Means 35 Thermometer 36 Wheel encoder 37 Support body 38 Inductive inspection coil 39 Support column 40 Marking

Claims (7)

A heating machine having an induction heating coil for heating a metal body such as a reinforcing bar or steel frame in a concrete structure by an eddy current, and an inverter device for supplying a high-frequency alternating current to the induction heating coil;
A thermography device capable of detecting the state of the concrete structure by imaging the surface temperature distribution measured by a measuring instrument such as an infrared camera that measures the surface temperature distribution of the concrete structure;
A coil moving carriage for moving the induction heating coil along the concrete structure, and a measuring instrument moving carriage for moving the measuring instrument along the concrete structure,
The non-destructive inspection apparatus for a concrete structure, wherein the measuring instrument carriage is controlled so as to always track the coil moving carriage with a certain delay.   The nondestructive inspection device for a concrete structure according to claim 1, further comprising a marking unit capable of marking an arbitrary position on the surface of the concrete structure at a rear end portion of the measuring instrument moving carriage.   The moving carriage for coils and the moving carriage for measuring instruments are combined with one moving carriage, the induction heating coil is supported at the front end of the moving carriage, and the measuring instrument is installed at the rear end. Nondestructive inspection equipment for concrete structures. An induction heating coil that heats a metal body such as a reinforcing bar or steel frame in a concrete structure by eddy current, an inverter device that supplies high-frequency alternating current to the induction heating coil, and an infrared that measures the surface temperature distribution of the concrete structure A measuring instrument such as a camera, a thermography device capable of detecting the state of the concrete structure by imaging the surface temperature distribution measured by the measuring instrument, and the induction heating coil is moved along the concrete structure. Using an apparatus comprising a coil moving carriage and a measuring instrument moving carriage for moving the measuring instrument along the concrete structure,
The induction heating coil is moved from one end side to the other end side of the concrete structure while heating the metal body, and the induction heating coil is tracked by the measuring device with a delay of a certain time from the induction heating coil. The surface temperature distribution at a position heated by the heating coil is measured after a predetermined time has elapsed, and the operation of imaging it is repeated from one end side to the other end side of the concrete structure, and based on the surface temperature distribution image at each position. A non-destructive inspection method for a concrete structure characterized by detecting the state of the concrete structure.   The nondestructive inspection method of the concrete structure of Claim 4 which determines the time interval when the said measuring device tracks an induction heating coil based on the covering concrete thickness and coil load electric power.   The temperature distribution image of the concrete structure surface portion measured by the measuring device for each moving time of the moving carriage is divided into a plurality of divided images, and the divided images corresponding to the respective moving times are arranged side by side and synthesized every time after heating. A nondestructive inspection method for a concrete structure according to claim 4, wherein a temperature distribution image of the surface portion of the concrete structure is formed and the state of the concrete structure is detected based on the temperature distribution image.   The nondestructive inspection method for a concrete structure according to claim 4 or 5, wherein marking is performed on a recognized defective portion of the concrete structure.

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