JP4081479B2 - Structure inspection method using infrared camera, structure temperature environment monitoring system, structure imaging time notification system, structure specimen - Google Patents

Description

  The present invention relates to a method for investigating the internal damage state of a structure such as concrete or tile using an infrared camera, and also to monitoring the surface temperature of a test body imitating the structure or structure while monitoring the surface temperature of the structure. It is related with the system which alert | reports the imaging | photography time by.

  Concrete structures such as bridges and overpasses are affected by weather changes, ground changes and load loads over the years in addition to their own deterioration. When these are collected and the adverse conditions overlap, partial destruction or peeling of the concrete structure may occur, leading to damage to third parties or accidents.

  Therefore, in order to prevent the concrete structure from peeling off, it is necessary to continuously inspect and monitor the concrete structure.

  At present, the hammering sound survey method is widely implemented as an inspection method for concrete structures.

  However, the hammering sound investigation method is a method in which a human actually strikes a site to be investigated to investigate a damaged state, and it is necessary to approach a concrete structure. However, in reality, there are many places where it is difficult to approach easily due to crossing conditions such as underpass roads, railways, rivers, etc., and the survey area is also large.

  For this reason, the sound inspection method still has problems to be solved in terms of efficiency such as traffic regulation, processing capacity, and cost. In addition, it is difficult to conduct an accurate survey because the sound-taping survey method depends on experience and intuition.

  Therefore, in recent years, since it is not necessary to approach a concrete structure and a wide range of surveys can be performed with high efficiency, the infrared survey method has been studied as an auxiliary inspection method for extracting the places where the sound inspection is necessary.

  In the infrared survey method, the concrete surface temperature is measured by an infrared camera, and the healthy part and the damaged part without damage are discriminated by the temperature difference.

  The principle of the infrared survey method will be described with reference to FIGS.

  FIGS. 1A and 1B are schematic diagrams showing heat flow and temperature change in concrete accompanying environmental temperature change.

  As shown in FIG. 1 (a), since the damaged portion 2 such as a void near the surface layer portion of the concrete structure 1 serves as a heat insulation tank against heat flow, the outside air temperature is higher than the concrete and the heat flow from the concrete surface such as daytime. When going inside, the surface in the vicinity of the damaged portion 2 becomes a high temperature region, and the healthy portion 3 becomes a low temperature region. On the other hand, when the heat flow goes from the inside of the concrete to the surface, such as at night, the damaged part 2 becomes a low temperature region and the healthy part 3 becomes a high temperature region.

  FIG. 2 illustrates the daily temperature change of the outside air temperature, the sound part 3 and the damaged part 2 in the concrete viaduct.

  In FIG. 2, if the surface of the investigation target part of the concrete structure 1 is photographed with an infrared camera when the temperature difference between the healthy part 3 and the damaged part 2 exceeds a predetermined value, the surface of the concrete structure with a temperature difference Thus, it is possible to obtain an image of the temperature distribution and to determine that the investigation target site is damaged.

  However, the temperature difference between the healthy part 3 and the damaged part 2 depends on the environmental conditions of the site to be investigated, that is, location, season, time zone, and the like.

  For this reason, in order to conduct an infrared survey method, even if a person visits the site and takes an image with an infrared camera, the temperature difference between the healthy part 3 and the damaged part 2 is small at the time of taking the image. In spite of this, it may be misjudged that there is no abnormality. For this reason, not only was the cost associated with the survey wasted, but the reliability of the survey results was lacking.

  In addition, since the infrared inspection method is an auxiliary inspection method for extracting a portion where a sound hitting check is necessary, it should be possible to accurately determine whether or not the sound hitting check should be performed and the priority of the sound hit checking at each location.

  In other words, depending on the depth and shape of the damaged portion 2 inside the concrete structure, damage may progress by hitting the hammering sound survey method and the peeling time may be advanced. In other words, as a result of the infrared inspection method, if it was determined that there was an abnormality inside the structure, it would be sufficient if the concrete on the surface could be knocked down, but it would be damaged without being knocked down. May occur and may cause damage to third parties due to peeling. In addition, as a result of infrared survey method implementation, it was determined that there was an abnormality inside the structure, so if we decided to implement the sound impact survey method uniformly, depending on the survey area and position, a great deal of time and labor would be spent on the survey. Therefore, an efficient inspection cannot be performed.

  The present invention has been made in view of such a situation, and it is possible to determine the time when the survey by the infrared survey method can be accurately performed, to reduce unnecessary costs associated with the survey, and to improve the reliability of the survey results. To solve the problem.

  The following Non-Patent Document 1 is a document showing a general technical level related to the infrared survey method.

  In this Non-Patent Document 1, a test piece having a simulated defect (damaged part) is prepared, this test piece is attached to the surface of a concrete structure, and the temperature distribution and test on the surface of the concrete structure are measured by an infrared camera. An invention is described in which the temperature distribution of a piece is photographed and the time when the infrared survey method should be performed is determined from the comparison result.

  However, the technique disclosed in Non-Patent Document 1 has to approach the concrete structure and attach the test piece. In addition, when there are a plurality of investigation target parts, a test piece must be attached to each investigation target part. For this reason, as with the hammering sound investigation method, problems associated with the approach of the structure occur, and a test piece has to be installed at each investigation target site, so the labor required for the work is enormous and the work efficiency is reduced. To do.

That is, according to the technique disclosed in Non-Patent Document 1, the problem to be solved by the present invention cannot be achieved.
Pamphlet of Sumitomo Osaka Cement Co., Ltd. “Non-destructive inspection technology using infrared thermography”

The first invention is
In the structure investigation method using an infrared camera, the surface of the structure is photographed with an infrared camera, and the damage state inside the structure is investigated based on the temperature distribution of the photographed structure surface.
A test body having a damaged part including damage inside and a healthy part not including damage inside, a temperature sensor for a damaged part for detecting a surface temperature of the damaged part among the surfaces of the test body, and a surface of the test body A temperature sensor for a healthy part for detecting the surface temperature of the healthy part and a temperature sensor for a structure for detecting the surface temperature of a predetermined part of the structure,
The test body is disposed at a position where the detection temperature of the temperature sensor for the structure and the detection temperature of the temperature sensor for the healthy part are substantially the same,
When the difference between the temperature detected by the damaged part temperature sensor and the temperature detected by the healthy part temperature sensor is greater than or equal to a predetermined value, the site to be investigated of the structure is imaged by an infrared camera.

The first invention will be described with reference to FIGS.
According to the first invention, when searching for the installation location of the test specimens 60, 60 ', the test specimens 60, 60' are arranged at an appropriate location around the structure 20 to be investigated, and the temperature sensor for the healthy part 62 and the temperature data of the structure temperature sensor 63 are compared. If both temperature data at the location are substantially the same, the test specimens 60 and 60 'are installed at the location. Then, at the time when the temperature difference between the damaged portion temperature sensor 61 and the healthy portion temperature sensor 62 of the test bodies 60 and 60 ′ becomes equal to or greater than a predetermined value, the investigation target regions 21 and 23 are imaged by the infrared camera.

The second invention is
In the structure investigation method using an infrared camera, the surface of the structure is photographed with an infrared camera, and the damage state inside the structure is investigated based on the temperature distribution of the photographed structure surface.
A test body having a damaged part including damage inside and a healthy part not including damage inside, a temperature sensor for a damaged part for detecting a surface temperature of the damaged part among the surfaces of the test body, and a surface of the test body A healthy part temperature sensor for detecting the surface temperature of the healthy part and an outside air temperature sensor for detecting outside air,
The test body is installed around the structure,
Photograph the surface of the structure with an infrared camera,
The difference between the detected temperature of the damaged portion temperature sensor and the detected temperature of the healthy portion temperature sensor, the expected average temperature on the day of shooting, the detected temperature of the outside air temperature sensor, and the detection of the outside air temperature sensor a predetermined time ago The difference between the temperature and the surface temperature of the damaged part of the structure and the surface temperature of the healthy part are predicted every predetermined time ,
When the predicted temperature difference falls below a predetermined temperature difference at which the damaged part and the healthy part of the structure can be distinguished from each other by the infrared camera image, the imaging of the structure by the infrared camera is terminated.

The third invention is the second invention,
Prepare a temperature sensor for a structure that detects the surface temperature of a predetermined part of the structure,
The test body is installed at a position where the detected temperature of the temperature sensor for structures and the detected temperature of the temperature sensor for healthy parts are substantially the same.

A fourth invention is the second invention,
Before the structure is photographed by the infrared camera, the surface of the damaged part and the healthy part of the specimen are photographed by the infrared camera, and the temperature sensor for the damaged part is detected when the damaged part and the healthy part can be distinguished by the infrared camera. The difference between the temperature and the detected temperature of the healthy part temperature sensor is stored as the predetermined temperature difference .

The second, third, and fourth inventions will be described with reference to FIGS.
In the investigation by the infrared camera, the surface temperature of the damaged part is detected among the test bodies 60 and 60 'having a damaged part including damage inside and a healthy part not including damage inside, and the surfaces of the test bodies 60 and 60'. The temperature sensor 61 for a damaged part, the temperature sensor 62 for the healthy part which detects the surface temperature of the healthy part among the surfaces of the test body, and the outside air temperature sensor 71 which detects the temperature of the outside air are prepared. Also, a structure temperature sensor 63 for detecting the surface temperature of a predetermined portion of the structure 20 is prepared.

  When searching for the installation location of the test bodies 60, 60 ', the test bodies 60, 60' are arranged at appropriate locations around the investigation object 20, and the temperatures of the healthy part temperature sensor 62 and the structure temperature sensor 63 are measured. Compare the data. If both temperature data at the location are substantially the same, the test specimens 60 and 60 'are installed at the location.

  Before photographing with the infrared camera, the specimen 60, 60 'is photographed with the infrared camera, and the temperature difference between the temperature sensors 61, 62 at the time when the damaged part and the healthy part of the specimen 60, 60' can be distinguished with the infrared camera. Store td. This temperature difference td is a limit value of the temperature difference that can be distinguished by the image captured by the infrared camera.

  During imaging of the structure 20 by the infrared camera, the difference between the detected temperature of the damaged portion temperature sensor 61 and the detected temperature of the healthy portion temperature sensor 62, the detected temperature of the outside air temperature sensor 71, and the outside air temperature sensor a predetermined time ago. The temperature difference (t) between the surface temperature of the damaged portion of the structure and the surface temperature of the healthy portion is predicted using the difference between the detected temperature 71 and the detected temperature. If the predicted temperature difference (t) is less than the stored temperature difference td, there is a possibility that the images captured by the infrared camera cannot be distinguished from each other. Therefore, at this time, it is determined that the photographing time with the infrared camera has ended, and the investigation with the infrared camera is ended.

The fifth invention
In a structure photographing time notification system for photographing the structure end time when photographing the surface of the structure with an infrared camera and investigating the damage state inside the structure based on the temperature distribution of the photographed structure surface ,
A test body of a structure having a damaged part including damage inside and a healthy part including no damage inside;
A temperature sensor for a damaged portion that detects the surface temperature of the damaged portion of the surface of the test body; and
A temperature sensor for a healthy part that detects the surface temperature of the healthy part of the surface of the test body; and
An outside air temperature sensor for detecting the outside air temperature;
A temperature difference storage means for storing a predetermined temperature difference capable of distinguishing a damaged part and a healthy part of a structure from an image of an infrared camera ;
The difference between the detected temperature of the damaged portion temperature sensor and the detected temperature of the healthy portion temperature sensor, the expected average temperature on the day of shooting, the detected temperature of the outside air temperature sensor, and the detection of the outside air temperature sensor a predetermined time ago A temperature difference prediction means for predicting the difference between the surface temperature of the damaged part of the structure and the surface temperature of the healthy part at predetermined time intervals using the difference between the temperature and
An end signal output means for outputting a photographing end signal when the temperature difference predicted by the temperature difference prediction means falls below a predetermined temperature difference stored in the temperature difference storage means;
And an end time notifying means for notifying that the image capturing possible time of the infrared camera has ended at the time when the image capturing end signal is input.

A sixth invention is the fifth invention ,
The temperature sensor for damaged parts and the temperature sensor for healthy parts are provided with the communication means which transmits the temperature data based on detected temperature to the temperature difference prediction means via a communication line.

A seventh invention is the fifth invention ,
The end time notification means includes a portable electronic communication device,
Communication means for transmitting a photographing end signal from the temperature difference prediction means to the electronic communication device via a communication line is provided.

The fifth, sixth, and seventh inventions will be described with reference to FIGS. 15, 16, and 17. FIG.
The test bodies 60 and 60 'have a damaged part 12 including damage inside and a healthy part 13 including no damage inside. The damaged part temperature sensor 61 detects the surface temperature of the damaged part 12 among the surfaces of the test bodies 60 and 60 '. The healthy part temperature sensor 62 detects the surface temperature of the healthy part 13 among the surfaces of the test bodies 60 and 60 '. The outside air temperature sensor 71 detects the temperature of outside air.

  The temperature difference predicting means 80 includes a difference between the detected temperature of the damaged portion temperature sensor 61 and the detected temperature of the healthy portion temperature sensor 62, the detected temperature of the outside air temperature sensor 71, and the detected temperature of the outside air temperature sensor 71 before a predetermined time. Are used to predict the difference between the surface temperature of the damaged portion of the structure 20 and the surface temperature of the healthy portion.

  Prior to photographing by the infrared camera, the specimens 60 and 60 'are photographed by the infrared camera, and the temperature of the temperature sensors 61 and 62 when the damaged part and the healthy part of the specimens 60 and 60' can be distinguished by the infrared camera. The difference td is stored. This temperature difference td is a limit value of the temperature difference that can be distinguished by the image captured by the infrared camera.

  If the predicted temperature difference (t) is less than the stored temperature difference td, there is a possibility that the images captured by the infrared camera cannot be distinguished from each other. Therefore, the end signal output means 80 determines that the photographing time by the infrared camera has ended at this point, and outputs a photographing end signal. The end time notifying means 81 inputs a shooting end signal and notifies the end of the shooting possible time of the infrared camera with a warning sound, warning light, warning message or the like.

  Temperature data is transmitted from the test bodies 60, 60 ′ to the temperature difference predicting means 80 via the communication line 85, and an imaging end signal is transmitted from the end signal output means 80 to the end time notifying means 81 via the communication line 85.

The eighth invention
Whether the temperature distribution on the surface of the structure is in a state suitable for investigation, which is used when photographing the surface of the structure with an infrared camera and investigating the damage state inside the structure based on the temperature distribution on the photographed structure surface In order to determine whether or not, in the test body of the structure having a damaged portion including damage inside and a healthy portion not including damage inside, which is imitated to the structure,
A temperature sensor for a damaged portion for detecting a surface temperature of the damaged portion;
A healthy part temperature sensor for detecting the surface temperature of the healthy part;
A temperature sensor for a structure for detecting a surface temperature of a predetermined part of the structure;
A dew condensation sensor that detects dew condensation on the surface of the structure;
Data transmission for transmitting temperature data related to detection temperatures of the damaged part temperature sensor, the healthy part temperature sensor, and the structure temperature sensor, and a signal indicating that condensation has been detected by the condensation sensor via a communication line And
And a data recording unit for recording temperature data relating to a temperature detected by the temperature sensor for the damaged part, the temperature sensor for the healthy part, and the temperature sensor for the structure.

  According to the present invention, since the surface temperature difference between the damaged part and the healthy part of the specimen is detected, it is possible to take a picture at a time when the temperature difference of the structure to be investigated is a predetermined value or more. , You can get accurate survey results. In addition, the test body only needs to be installed at a location different from the site to be investigated, and it is not necessary to approach the structure to be investigated as in the hitting investigation method, so that the work can be performed efficiently.

  According to the present invention, since it is possible to determine the time when the survey by the infrared survey method can be accurately performed, it is possible to reduce useless costs associated with the survey and to improve the reliability of the survey results.

  In particular, according to the first and third inventions, the test body is installed in a temperature environment equal to the temperature environment of the structure. For this reason, the reliability of the temperature data obtained with a test body improves.

  Further, according to the second, sixth, and seventh inventions, the surface temperature difference between the damaged portion and the healthy portion of the structure is predicted. For this reason, the photographing time by the infrared camera becomes more appropriate.

  According to the fifth and eighth inventions, the temperature data of the specimen is transmitted via communication. That is, it becomes possible to confirm temperature data in a remote place. Based on this temperature data, the investigator should visit the site at an appropriate time and start the investigation. Therefore, the time for the investigator to wait at the work site is shortened, and the work efficiency is further improved.

  According to the seventh aspect of the invention, when the surface temperature difference between the damaged part and the healthy part of the structure is not present, the photographing end time by the infrared camera is notified. Then, the investigator can finish the photographing end time with the infrared camera at an appropriate timing. Therefore, useless investigation is eliminated, the cost is further reduced, and the reliability is further improved.

Embodiments according to the present invention will be described below with reference to the drawings.
In the present embodiment, a concrete test body including a cavity (damaged part) and a concrete filling part (healthy part) is made to simulate the structure to be investigated, and the surface temperature of the cavity of the test body is determined. The time of infrared survey of the structure is judged by referring to the difference in the surface temperature of the concrete filling part. If the surface temperature difference between the cavity of the test specimen and the concrete filling part is more than a certain level, the damaged part and the sound part of the actual structure should have the same surface temperature difference. If there is a surface temperature difference between the damaged part and the healthy part of the structure, the damaged part and the healthy part can be distinguished from each other by the temperature distribution photographed by the infrared camera. For this reason, in the present invention, the surface temperature difference between the cavity and the filling portion of the test body is measured.

  By the way, the present invention has been obtained by improving the embodiment of the “method for investigating a structure using an infrared camera (Japanese Patent Application No. 2003-376932)” previously filed by the present inventor. In describing the present invention, it is useful to describe the embodiment of Japanese Patent Application No. 2003-376932. Therefore, the embodiment of Japanese Patent Application No. 2003-376932 will be described as Example 1, and the present embodiment, which is an improvement of Example 1, will be described as Example 2. In the first embodiment, it is assumed that the damage included in the structure is a “cavity”. In Example 2, it is assumed that the damage included in the structure is “floating / peeling”.

[Structure of specimen]
FIG. 3 shows the appearance of the test body 10 used to determine the implementation time of the infrared survey method.

  The test body 10 includes a cube 11 made of concrete having a cavity 12 as a damaged portion 2 inside, a heat insulating material 14 provided so as to cover the concrete cube 11 leaving the surface 11a (photographing surface), and a concrete cube. Temperature sensors 15 and 16 embedded in locations corresponding to the cavity portion 12 (damaged portion 2) and the concrete filling portion 13 (healthy portion 3) other than the cavity portion 12, and the concrete cube 11 inside. The reinforcing bar 17 is made of.

  Phenomena such as “peeling” and “floating” in a concrete structure means that the reinforcing bar corrodes and expands, and the adhesion between the concrete and the reinforcing bar is broken, and the part that has reached such a state may peel off. Many.

  Therefore, the cavity 12 is provided in the vicinity of the reinforcing bar 17 and on the surface 11a side of the concrete cube 11.

  As the temperature sensors 15 and 16, for example, a thermistor type small digital thermometer was used. Of the surface 11a of the concrete cube 11, the part corresponding to the cavity 12 was scraped off, and the temperature detection part of the temperature sensor 15 was bonded with embedded concrete bond. Similarly, the portion corresponding to the concrete filling portion 13 of the surface 11a of the concrete cube 11 was scraped off, and the temperature detection portion of the temperature sensor 16 was bonded with an embedded concrete bond.

  Desirably, the test body 10 is set to a size and weight that can be moved by an investigator alone.

  However, when the test body 10 is downsized, the temperature change differs from that of the concrete structure 1 such as an actual bridge. Therefore, in order to bring the test body 10 closer to an actual bridge or the like, the surface other than the imaging surface 11a is covered with a heat insulating material 14 such as fiberglass, natural rubber, or wood. As the heat insulating material 14, for example, a fiber glass having a thermal conductivity of 0.05 W / m · K can be used.

[Location of specimen]
FIG. 4 shows the installation location of the test body 10.

  In the embodiment, it is assumed that the bridge 20 is an investigation target, and the wall height column portion 21 and the base portion 22 of the bridge 20 are investigated as respective investigation target portions.

  The test body 10 has the same environmental conditions as the survey target portions 21 and 22 of the bridge 20 and is installed at a location different from the survey target portions 21 and 22.

  Since the wall height column 21 of the bridge 20 has a relatively large amount of solar radiation and a well-ventilated environmental condition, the test body 10 for judging the investigation time of the wall height column 21 is near the bridge 20 and is similarly exposed to sunlight. It is installed on a lot of airy ground. In addition, since the base portion 22 of the bridge 20 has a relatively low solar radiation and poorly ventilated environmental conditions, the test body 10 ′ for determining the investigation period of the base portion 22 is near the bridge 20 and is similarly exposed to the solar radiation. It is installed on the ground where there are few and poor ventilation.

  When the equipment for judging the survey time is prepared as described above, the survey time is judged by the following procedure.

[Determining the season and time zone for infrared surveys]
As described with reference to FIGS. 1 and 2, when the temperature difference between the damaged portion 2 and the healthy portion 3 in the investigation target site is equal to or greater than a predetermined value, the investigation by the infrared investigation method can be accurately performed.

  However, throughout the year, the temperature difference between the damaged part 2 and the healthy part 3 changes, and there are seasons in which the temperature difference is relatively large, and there are seasons in which the temperature difference is relatively small. In addition, there are time periods in which the temperature difference is relatively large during one day, and there are time periods in which the temperature difference is relatively small.

  Therefore, temperature data detected by the temperature sensors 15 and 16 of the test specimens 10 and 10 'are collected throughout the year, and analyzed to obtain a concrete filling portion 13 (healthy portion 3) and a cavity portion 12 (damage portion 2). Data on the correspondence relationship between the temperature difference and the season and time zone is acquired in advance. If the temperature difference between the concrete filling portion 13 and the cavity portion 12 detected by the temperature sensors 15 and 16 of the test specimens 10 and 10 'is a predetermined value or more, the test specimens 10 and 10' Similarly, the healthy part 3 and the damaged part 2 of the investigation target parts 21 and 22 having the same environmental conditions are considered to have a temperature difference equal to or more than a predetermined value. For example, accurate survey results can be obtained.

  5 (a), (b), (c), and (d) show the daily temperature transition detected by the temperature sensors 15 and 16 of the test body 10 for each season.

  If the daily range of the day (the difference between the minimum temperature and the maximum temperature in the day) is large (over 10 ° C), the temperature difference between the damaged part 2 and the healthy part 3 becomes large. It is said.

  However, as shown in FIG. 5, the temperature difference between the concrete filling part 13 (healthy part 3) and the cavity part 12 (damaged part 2) appears depending on the season even if the daily temperature difference is 10 ° C or more from the detection result of the outside air temperature. You can see that there is a difference. In winter (December-February), the temperature difference during the day is around 0.5 ° C, while the temperature difference in spring (March-May) and autumn (September-November) is about It is moving around 1.0 ° C. This is because not only the daily difference but also environmental conditions such as ventilation and wind speed affect the temperature difference.

  By collecting such data, data on the correspondence relationship between the season and time zone that can be investigated is acquired as shown in the table of FIG. 6, for example.

  As shown in Fig. 6, during the daytime of winter (December-February), the survey can be conducted only for 3 hours, while during the daytime of spring (March-May), the survey is conducted for 6 hours. It is possible, and it can be determined that the spring daytime is more suitable for long-term surveys.

  From the data shown in FIG. 6, the investigator determines the season and time zone in which the temperature difference is greater than or equal to a predetermined value and is convenient for visiting the site.

  As a result, it is possible that the temperature difference is likely to be smaller than the predetermined value and it is possible to avoid going to the site during the season and time that are not suitable for the survey, so it is possible to control the expenditure of unnecessary survey costs. Can do.

[Confirmation of temperature difference at the site]
However, even if you actually visit the site, the temperature difference is small due to the effects of rainfall, etc., which may not be suitable for the survey. Therefore, when the user visits the site, the data of the detection values of the temperature sensors 15 and 16 of the specimen 10 are acquired before the investigation, and after confirming that the temperature difference has become a predetermined value or more, the image is taken by the infrared camera. It is desirable to implement.

  FIG. 7 shows the time variation of the cavity 12 (damaged part 2) and the concrete filling part 13 (healthy part 3) obtained from the outside air temperature on the survey day, the detection results of the temperature sensors 15 and 16 of the test body 10. . A time zone in which the temperature difference between the cavity portion 12 (damaged portion 2) and the concrete filling portion 13 (healthy portion 3) is a predetermined value or more is determined as a time zone suitable for the investigation.

  If a time zone suitable for such a survey does not appear, the survey is postponed.

[Shooting with an infrared camera]
The investigator uses the infrared camera to perform the same operation as that of the test body 10 in the time zone in which the temperature difference between the healthy part 3 and the damaged part 2 obtained from the detection results of the temperature sensors 15 and 16 of the test body 10 is equal to or greater than a predetermined value. The part 21 to be investigated for environmental conditions is photographed.

  Similarly, the investigator uses the infrared camera to detect the test object during the time zone when the temperature difference between the healthy part 3 and the damaged part 2 obtained from the detection results of the temperature sensors 15 and 16 of the test object 10 ′ exceeds a predetermined value. An investigation target region 22 having the same environmental condition as 10 'is photographed.

  As a result, it becomes possible to image the investigation target region under the condition that the temperature difference is surely equal to or greater than the predetermined value, and an accurate investigation result can be obtained. In addition, the test body only needs to be installed at a location different from the site to be investigated, and it is not necessary to approach the structure to be investigated as in the hitting investigation method, so that the work can be performed efficiently.

  As described above, according to the present embodiment, it is possible to determine the time when the survey by the infrared survey method can be accurately performed, so that it is possible to reduce the wasteful cost associated with the survey and improve the reliability of the survey result. Can be made.

  Next, a method for determining the depth and shape of the damaged portion 2 of the concrete structure 1 will be described.

[Damage pattern]
FIG. 8 shows five damage patterns (1), (2), (3), (4), and (5) with different depths and shapes of the damaged portion 2 of the concrete structure 1 and the priority of the sounding investigation. The correspondence with degrees is shown.

  The accidental fall of the concrete piece is that the rebar 17 expands and the concrete on the surface peels off, and the concrete block falls. The priority of the hit sound investigation differs depending on the depth and shape of the damaged portion 2.

  The damage pattern (1) is a pattern of a damage situation in which a sufficient covering is ensured but the damaged portion 2 is present 4 cm behind the surface. When the hitting investigation is performed, it is a case where only the abnormal sound does not come off. The priority of the sounding investigation is “observation”, and it is not particularly necessary to conduct the sounding investigation quickly.

  The damage pattern (2) is a pattern of a damage situation in which the damaged portion 2 exists about 2 cm from the surface. When the hammering sound investigation is performed, there is a case where a hole is made in the damaged portion 2 and then the concrete piece may fall. The priority of the sounding investigation is “caution”, and it is necessary to conduct the sounding investigation while monitoring.

  The damage pattern (3) has a cover depth of 4 cm, the same as the damage pattern (1), but damage proceeds from the damage pattern (1) and a part of the damaged part 2 is at an angle of 45 ° toward the concrete surface. It is the pattern of the damage situation which inclines and has reached 2 cm from the surface. When the hammering sound investigation is performed, there is a possibility that the concrete piece will fall due to a heavy hit. The priority of the sounding investigation is “caution”, and it is necessary to conduct the sounding investigation while monitoring.

  The damage pattern (4) has a covering depth of 2 cm, the same as the damage pattern (2), but damage proceeds from the damage pattern (2) so that a part of the damaged part 2 is at an angle of 45 ° toward the concrete surface. It is the pattern of the damage situation which inclines and has reached the surface vicinity. When the hammering survey is conducted, there is a high possibility that the concrete piece will fall due to a heavy hit. The priority of the sounding investigation is “Caution”, and it is necessary to conduct the sounding investigation and drop the concrete pieces in advance.

  The damage pattern (5) is a damage state pattern in which damage has progressed from the damage pattern (3) and a part of the damaged portion 2 has reached the vicinity of the surface. When the hammering survey is conducted, there is a high possibility that the concrete piece will fall due to a heavy hit. The priority of the sounding investigation is “Caution”, and it is necessary to conduct the sounding investigation and drop the concrete pieces in advance.

[Create FEM analysis model]
When five damage patterns are determined as described above, models 31 to 35 for FEM analysis are created for each damage pattern (1) to (5).

  FIG. 9 shows an FEM analysis model 31 as a representative.

  The FEM analysis model 31 is a three-dimensional model having each of an x axis (concrete surface horizontal direction), a y axis (concrete surface vertical direction), and a z axis (concrete surface depth direction). 4 can be modeled.

[Preparation and installation of test specimen]
The test specimens 10 and 10 'described with reference to FIG. 3 are prepared, and the test specimen 10 is located at the same environmental conditions as the investigation target portions 21 and 22 of the bridge 20 which is an actual concrete structure as described with reference to FIG. 10 'is installed.

[Shooting with an infrared camera]
Hereinafter, the test body 10 will be described as a representative.

  FIG. 7 shows the transition of each temperature of the cavity 12 (damaged part 2) and the concrete filling part 13 (healthy part 3) detected by the temperature sensors 15 and 16 of the test body 10. Here, the time when the temperature difference between the cavity portion 12 (damaged portion 2) and the concrete filling portion 13 (healthy portion 3) is equal was t0 (8:45 minutes). The temperature difference became 0.8 ° C. at time t1 when 3 hours passed from this time t0, and an image of the surface of the investigation target region 21 was taken by the infrared camera at time t1.

[Calculation of heat flow, FEM analysis]
Next, the investigator calculates the heat flow given to the investigation target region 21 from the detection result of the temperature sensors 15 and 16 of the test body 10 until the imaging time t1, and uses the heat flow to perform a plurality of FEM analyzes. FEM analysis is performed for each model 31-35.

  That is, the calculation was performed by unsteady three-dimensional heat conduction analysis while changing the heat flow rate. However, it is difficult to generally indicate the magnitude of the thermal conductivity between the air and the concrete because the thermal conductivity changes with the temperature of the air at the same time as the air convection occurs.

  Therefore, the heat flow transferred from the air to the object surface is changed and inputted within the time period from time t0 to time t1, and the cavity 12 (damaged part 2) and concrete filling part 13 (healthy part) of the FEM analysis model are input. The convergence calculation is repeated until each surface temperature corresponding to 3) reaches each temperature detected at time t1 in FIG.

  FIG. 10 shows the calculation results for each of the FEM analysis models 31 to 35. Each mesh on the concrete surface (xy plane) of the FEM analysis models 31 to 35 can be shown as a hue (or density) corresponding to the temperature.

[Judgment of actual structural damage]
As shown in FIG. 10, depending on the difference between the damage patterns (1) to (5), the hue (or concentration) on the concrete surface (xy plane) of the FEM analysis models 31 to 35 is manifested. I can see that they are different.

  Therefore, the temperature distribution, that is, the hue (or density) distribution on the concrete surface photographed by the infrared camera is the hue (or density) distribution on the concrete surface (xy plane) of any of the FEM analysis models 31-35. , It can be determined that the damage pattern corresponding to the matched FEM analysis model is the actual damaged state of the concrete structure 1.

  Therefore, the investigator calculates the surface temperature distribution (hue (or density) distribution) for each of the FEM analysis models 31 to 35 calculated and the surface temperature distribution (hue (or density) distribution) of the photographed investigation target region 21. Match. For example, as shown in FIG. 10, if a captured image 41 of the investigation target region 21 is obtained, the surface temperature distribution (hue (or density) distribution) of the surface temperature distribution (hue (or hue (or density) distribution)) of the FEM analysis model 31 is obtained. Therefore, it is determined that the damage pattern (1) corresponding to the matched FEM analysis model 31 is the actual damage state of the site 21 to be investigated. Similarly, if a captured image 42 of the investigation target region 21 is obtained, it is determined that the damage pattern (2) corresponding to the FEM analysis model 32 that matches the actual image is the damage state of the investigation target region 21. If the captured image 43 of the investigation target region 21 is obtained, it is determined that the damage pattern (3) corresponding to the FEM analysis model 33 corresponding to the captured image 43 is the actual damage state of the investigation target region 21, and the investigation target If the captured image 44 of the part 21 is obtained, it is determined that the damage pattern (4) corresponding to the FEM analysis model 34 corresponding to the captured image 44 is the actual damage state of the part 21 to be investigated. If the captured image 45 is obtained, it is determined that the damage pattern (5) corresponding to the FEM analysis model 35 corresponding to the captured image 45 is the actual damage state of the investigation target region 21.As a result, the investigator can know the actual depth and shape of the damaged portion 2 from the damage pattern determined to be the actual damage state of the investigation target region 21, and the damage pattern and the hitting sound shown in FIG. It is possible to accurately determine the priority of the hitting sound investigation from the correspondence relationship of the investigation priorities.

  Similarly, the investigator also photographs the other investigation target parts 22 in the same manner, similarly calculates the FEM analysis models 31 to 35, and calculates the surface temperature distribution for each of the FEM analysis models 31 to 35. By comparing the surface temperature distribution of the photographed investigation target region 22 with each other, it is possible to determine that the damage pattern corresponding to the matched FEM analysis model is the actual damage state of the investigation target region 22. The depth and shape of the damaged portion 2 can be known, and the priority of the hitting investigation can be accurately determined from the correspondence between the damage pattern and the priority of the hitting investigation shown in FIG.

  As described above, according to this embodiment, it is possible to accurately determine the depth and shape of the damaged portion 2 inside the concrete structure. It is possible to accurately determine the priority of the sounding investigation. In addition, unlike the prior art (Non-Patent Document 1), it is not necessary to perform photographing for a long time in order to determine the depth of the damaged portion, so that the work can be performed efficiently.

  Next, an embodiment in which the depth and shape of the damaged portion 2 can be determined without performing FEM analysis will be described.

[Determination of damage pattern]
Also in this embodiment, five damage patterns (1) to (5) are determined according to the damage state as in the above-described embodiment.

[Association between damage pattern and temperature transition pattern]
The temperature line graphs 51-55 of FIG. 10 have each shown the temperature transition of the y-axis direction in the concrete surface (xy plane) of each FEM analysis model 31-35. The temperature line graphs 51 to 55 show the transition of the temperature from the center of the damaged portion 2 toward the healthy portion 3. Looking at each temperature line graph 51-55, it can be seen that the shape and gradient of the temperature line graph are different for each FEM analysis model 31-35, that is, for each damage pattern (1)-(5). .

  That is, the temperature line graph has a gentle slope as it goes from the surface of the damaged portion 2 to the back. When the shape of the damaged portion 2 advances toward the surface, the temperature line graph shifts from a bell shape to a trapezoid shape. The damage pattern can be inferred from the characteristics of the shape of the temperature transition and the magnitude of the gradient.

  Therefore, as shown in FIG. 10, each temperature transition pattern, that is, the shape and gradient of each temperature line graph 51 to 55 is associated with each of the five damage patterns (1) to (5). Further, the damage pattern is not limited to the case where the damaged portion 2 is a hollow portion, and a damaged pattern such as a sand line or a crack may be prepared.

  For example, even in the case of a damage pattern in which the damaged portion 2 is sand streaks and cracks, the temperature line graph shows a triangular shape.

  Damage patterns (1) to (5) when the damaged portion 2 is a hollow portion, damage patterns (6) when the damaged portion 2 is sand streaks and cracks, the shape of the temperature line graph, temperature gradient (temperature transition) FIG. 11 shows the correspondence with the (pattern). For example, when a temperature transition pattern having a “bell shape” and a temperature gradient of “10 or more” is obtained, it can be determined that the damage pattern is (2).

[Shooting with an infrared camera]
When the above preparation is completed, the investigator determines that the temperature difference between the healthy part 3 and the damaged part 2 obtained from the detection results of the temperature sensors 15 and 16 of the specimen 10 is equal to or greater than a predetermined value, as in the above-described embodiment. During the time period in which the test object 10 becomes, an infrared camera is used to photograph the site to be investigated 21 under the same environmental conditions as the specimen 10.

[Judgment of temperature transition pattern from shooting results]
And the temperature transition of the y-axis direction (left-right direction) of the surface of the investigation object site | part 21 is calculated | required from an imaging result. Then, a temperature transition pattern that matches the obtained temperature transition is determined.

  FIG. 12 shows a line in the y-axis direction (left-right direction) of the surface of the investigation target region 21 photographed by the infrared camera as a temperature line graph, and illustrates the change with time. The temperature gradient of the temperature line graph is shown for each time in the figure. For example, at time 11:00, the temperature gradient of the temperature line graph is 11.42.

  For example, a thermal line graph can be created from an infrared image by using infrared image analysis software made by GORATEC of Germany and PE Professional.

  The shape of the temperature line graph shown in FIG. 12 is “bell-shaped” and the temperature gradient is “10 or more”, so that the shape of the temperature line in FIG. 10 is “bell-shaped” and the gradient is “10 or more”. It can be determined that the temperature transition pattern is the same as that of the graph 52 (see FIG. 11), and the damage pattern (2) corresponding to the temperature line graph 52 can be determined to be the actual damage state of the site to be investigated 21.

  Similarly, if it is determined that the temperature line graph created from the infrared image has the same temperature transition pattern as the temperature line graph 51 of FIG. 10, the damage pattern (1) corresponding to the temperature line graph 51 is actually If the temperature line graph created from the infrared image is determined to have the same temperature transition pattern as the temperature line graph 53 of FIG. 10, the temperature line is determined. It is determined that the damage pattern (3) corresponding to the graph 53 is the actual damage state of the site to be investigated 21, and the temperature line graph created from the infrared image has the same temperature transition as the temperature line graph 54 of FIG. If it is determined that the pattern is a pattern, the damage pattern (4) corresponding to the temperature line graph 54 is the actual damage of the site 21 to be investigated. If the temperature line graph created from the infrared image is determined to be the same temperature transition pattern as the temperature line graph 55 of FIG. 10, the damage pattern corresponding to the temperature line graph 55 is determined. (5) is determined to be the actual damaged state of the site to be investigated 21.

  If it is determined that the temperature line graph created from the infrared image has a triangular temperature transition pattern as shown in FIG. 11, the damage pattern (6) corresponding to the triangular temperature transition pattern, that is, sand It is determined that the crack is actually a damaged state of the investigation target site 21.

  As a result, the investigator determines the actual depth and shape of the damaged portion 2 or the type of the damaged portion (a hollow portion or sand line, It is possible to know whether it is a crack or not, and it is possible to accurately determine the priority of the sounding investigation from the correspondence between the damage pattern and the priority of the sounding investigation shown in FIG.

  In this embodiment, as in the above-described embodiment, it is assumed that the shooting date by the infrared camera is determined, the shooting date is taken to the site, and shooting is performed at a specific time zone and time. It is also possible to install an infrared camera on the site and continue shooting until a specific shape and gradient as shown in FIG. 12 are obtained.

Similarly, the investigator also captures images of other investigation target parts 22 in the same manner, similarly creates a temperature line graph from the infrared image, and uses the damage pattern corresponding to the temperature transition pattern that matches the temperature line graph to actually The damage state of the site 22 to be investigated can be determined, whereby the actual depth and shape of the damaged portion 2 or the type of the damaged portion can be known. From the correspondence of the priorities, the priority of the hit sound investigation can be accurately determined.

  As described above, according to this embodiment, it is possible to accurately determine the depth and shape of the damaged portion 2 inside the concrete structure. It is possible to accurately determine the priority of the sounding investigation. In addition, unlike the prior art (Non-Patent Document 1), it is not necessary to perform photographing for a long time in order to determine the depth of the damaged portion, so that the work can be performed efficiently.

  As described above, in Example 2, it is assumed that the damage included in the structure is “floating / peeling”.

[Experiment when damage is floating / peeling]
According to the inventor's experience, the following events were found with respect to Example 1. When the damaged part 2 of the investigation target part is a cavity, the time zone in which the surface temperature difference appears between the cavity part 12 and the concrete filling part 13 of the test body 10 is the damaged part 2 and the healthy part 3 of the investigation target part. It almost coincides with the time zone where the surface temperature difference appears. However, when the damaged part 2 of the site to be investigated is floating / peeling (hereinafter, simply referred to as “floating”), the time zone in which the surface temperature difference is present between the cavity 12 of the specimen 10 and the concrete filling part 13 is A little later than the time zone in which the surface temperature difference is present between the damaged part 2 and the healthy part 3 of the investigation target site. Therefore, the present inventor conducted the following experiment on floating.

  In conducting the experiment, imitations 95 and 96 of bridges having two types of floats as shown in FIGS. 13A and 13B were made. The imitations 95 and 96 are referred to as “specimens”. Three floats 95 a to 95 c (depths of 1 cm, 2 cm, and 3 cm) having different depths are formed on the specimen 95 shown in FIG. 13A, and the floats 95 a to 95 c exist inside the specimen 95. To do. These floats 95a to 95c are referred to as damage pattern 1. Three floats 96a to 96c (depths of 1 cm, 2 cm, and 3 cm) having different depths are formed on the specimen 96 shown in FIG. 13B, and the floats 96a to 96c are cracks that reach the surface of the specimen. Have These floats 96a to 96c are referred to as damage pattern 2.

  The specimen 10 and specimens 95 and 96 are installed in the laboratory, and the room temperature is changed in accordance with actual weather data. The surface temperature of the cavity 12 and the surface temperature of the healthy part 13 of the specimen 10 are provided. The surface temperature of the concrete filling portion of the specimen 95, the surface temperature of the floats 95a to 95c, the surface temperature of the concrete filling portion of the specimen 96, and the surface temperature of the floats 96a to 96c were measured. And the temperature difference of the surface temperature of a cavity part or a floating part and the surface temperature of a concrete filling part was calculated | required for every measurement time. As a result, FIG. 14 was obtained. FIG. 14A shows the experimental result of the damage pattern 1, and FIG. 14B shows the experimental result of the damage pattern 2. The temperature difference of the test body 10 is obtained by subtracting the surface temperature of the concrete filling portion from the surface temperature of the cavity portion, and the temperature difference of the specimens 95 and 96 is the surface temperature of the concrete filling portion from the floating surface temperature. Is required.

  In FIG. 14 (a), during the time zone when the surface temperature difference appears between the cavity 12 and the concrete filling portion 13 of the test body 10, the surface temperature difference appears between the floats 95a to 95c of the specimen 95 and the concrete filling portion. It can be seen that it is slightly behind the time zone. 14B, the surface temperature difference between the cavity portion 12 of the test body 10 and the concrete filling portion 13 is such that the surface temperature difference is between the floats 96a to 96c of the specimen 96 and the concrete filling portion. It can be seen that it is slightly behind the time zone.

  Therefore, the present embodiment predicts the surface temperature difference between the damaged portion and the healthy portion using the surface temperature difference between the cavity portion of the test specimen and the concrete filling portion, and performs an infrared survey based on the prediction result. One of the features. In addition, the present embodiment is characterized by transmitting various temperature data to a remote place by communication and notifying the investigator in the remote place of the photographing end time of the investigation target.

[System overall configuration]
FIG. 15 is a diagram showing an outline of a structure temperature environment monitoring system and an imaging time notification system.
Around the bridge 20, a test specimen 60 for the sun and a test specimen 60 'for the shade are installed. Each specimen 60, 60 ′ will be described later. There is a research office in a remote place away from the bridge 20, and a personal computer (hereinafter simply referred to as a personal computer) 80 provided with a monitor device 80a is provided in the research office. An investigator using an infrared camera carries a mobile electronic communication device 81. As the electronic communication device 81, a mobile phone, a simple mobile phone (PHS), a personal digital assistant (PDA), a laptop personal computer, or the like is applicable.

  Each test body 60, 60 'and the personal computer 80 can transmit and receive data to and from each other via communication means. The personal computer 80 and the electronic communication device 61 can transmit and receive data to and from each other via communication means. In the present embodiment, a publicly provided public communication line 85 is used as a communication means, and more specifically, an electronic mail service using the Internet is used. E-mail is transmitted / received between the test bodies 60, 60 ′ and the personal computer 80, and e-mail is transmitted / received between the personal computer 80 and the electronic communication device 81.

  The test bodies 60, 60 ', the personal computer 80, and the electronic communication device 81 may communicate with each other via a dedicated line instead of communicating with each other via the public communication line 85, or wirelessly. You may communicate with each other.

[Configuration of specimen]
Next, each test body 60, 60 'will be described.
FIG. 16A is a front view of the test specimen 60 for Hinata, and FIG. 16B is a side view of the test specimen 60 for Hyuga. The same components as those in FIG. 3 are denoted by the same reference numerals.

  The test body 60 has the cube 11 as shown in FIG. 3 and the heat insulating material 14 provided so as to cover the concrete cube 11 leaving the surface 11a (photographing surface). In addition, the test body 60 is a radiation thermometer 61 that detects the surface temperature of the cavity 12 as a variety of detection devices, directed to a portion of the surface 11a of the cube 11 corresponding to the cavity 12 (damaged part 2) inside the cube 11. A radiation thermometer 62 for detecting the surface temperature of the concrete filling portion 13 which is directed to a portion corresponding to the concrete filling portion 13 (healthy portion 3) inside the cube 11 in the surface 11a of the cube 11, and the wall of the bridge 20 It has a radiation thermometer 63 for a structure that is directed to the rail section 21 and detects the surface temperature of the wall rail section 21, and a condensation sensor 64 that detects condensation on the surface 11 a of the cube 11. Moreover, the test body 60 is a data recording device 65 that records the temperatures detected by the radiation thermometers 61 and 62, a communication device 66 that transmits / receives various data to / from an external communication device, and various communication management devices. And an antenna 67. Various electric devices use a lead storage battery 68 as a power source.

  The test specimen 60 for Hyuga may be provided on a paved road next to the bridge 20 in some cases. In such places, the pavement heat is strong, the temperature of the cube 11 rises due to the pavement heat, and the temperature environment of the cube 11 and the bridge 20 may change. In order to avoid the influence of pavement heat, the cube 11 is placed on a heat insulating plate 69 larger than the cube 11. Since the pavement heat rising from the pavement is blocked by the heat insulating plate 69, the cube 11 does not receive the pavement heat. The test body 60 is provided with a carriage so that it can easily move on the paved road.

  FIG. 17A is a front view of a shade specimen 60 ′, and FIG. 17B is a side view of the shade specimen 60 ′. Although the test body 60 ′ is different in appearance from the test body 60, many components are common, so only the different parts will be described.

  The structure radiation thermometer 63 is directed to the floor slab portion 23 of the bridge 20 to detect the surface temperature of the floor slab portion 23. Further, a temperature / humidity sensor 71 is provided instead of the dew condensation sensor 64. The test body 60 ′ is stored in the 100-leaf box 72 so as not to be exposed to the sun.

  Note that the cube 11 shown in FIGS. 16 and 17 may be provided with thermocouples 15 and 16 as shown in FIG. 3 instead of the radiation thermometers 61 and 62. However, the radiation thermometer 19 can be measured with higher accuracy than the thermocouple.

[Data processing in specimen]
FIG. 18 is a block diagram of the test body 60 for Hinata.
The radiation thermometers 61 and 62 perform temperature detection at regular intervals. The temperature data detected by the radiation thermometers 61 and 62 is output to the data recording device 65. The data recording device 65 records temperature data. The temperature data recorded by the data recording device 65, the condensation data detected by the condensation sensor 64, and the temperature data detected by the radiation thermometer 63 are output to the communication device 66. The communication device 66 includes a mail reporter board 66a, a communication module 66b, a DC / DC converter 66c, and a switch 66d. The mail reporter board 66a is a remote monitoring terminal board using a mobile communication service, and monitors temperature data and dew condensation data. The temperature data is transmitted as an e-mail to the public communication line 85 via the communication module 66b and the antenna 67. When the mail reporter substrate 66 a confirms that condensation has occurred on the surface of the cube 11, an email indicating the occurrence of condensation is transmitted to the public communication line 85 via the communication module 66 b and the antenna 67.

FIG. 19 is a block diagram of the shade 60 '.
The radiation thermometers 61 and 62 and the temperature / humidity sensor 71 detect temperature and humidity at regular intervals. The temperature data and humidity data detected by the radiation thermometers 61 and 62 and the temperature and humidity sensor 71 are output to the data recording device 65. The data recording device 65 records temperature data and humidity data. The temperature data and humidity data recorded by the data recording device 65 and the temperature data detected by the radiation thermometer 63 are output to the communication device 66. The communication device 66 includes a mail reporter board 66a, a communication module 66b, a DC / DC converter 66c, and a switch 66d. The mail reporter board 66a is a remote monitoring terminal board using a mobile communication service, and monitors temperature data and dew condensation data. The temperature data and humidity data are transmitted to the public communication line 85 through the communication module 66b and the antenna 67 as electronic mail.

  On the other hand, the test bodies 60 and 60 ′ receive an e-mail indicating a change command for the temperature / humidity detection time interval via the public communication line 85. When the mail reporter substrate 66b receives an e-mail via the antenna 67 and the communication module, it changes the time interval of temperature / humidity detection of the radiation thermometers 61 and 62 and the temperature / humidity sensor 71 in accordance with an e-mail change command. .

[Data processing on PC]
The personal computer 80 stores various data of the test bodies 60 and 60 'transmitted via the public communication line 85, and uses the following equation (1) to determine the surface temperature difference between the damaged part and the healthy part to be investigated. Predict calculations every hour.
Temperature difference (t) = B1 + B2 x specimen temperature difference (t) + B3 x daily average temperature + B4 x temperature difference (t-40)
... (1) (t: time (minutes))
In the above equation (1), the specimen temperature difference (t) is the surface temperature difference between the cavity 12 of the specimens 60 and 60 'and the concrete filling part 13 at time t. It is obtained by the detection value of the radiation thermometers 61 and 62 provided in the '. The daily average temperature is the expected average temperature of the day, and can be obtained from weather forecasts and weather data. The temperature difference (t-40) is the difference between the temperature at the time t and the temperature 40 minutes before the time t, and is obtained from the detection value of the temperature / humidity sensor 71 provided in the test body 60 '. . B1 to B4 are non-standardized coefficients, and are obtained corresponding to the floats 95a to 95c and 96a to 96c as shown in FIG.

  Each non-standardized coefficient is obtained as a result of time series analysis. Referring to the results of FIGS. 14 (a) and 14 (b), the time zone in which the surface temperature difference appears between the cavity portion 12 and the concrete filling portion 13 of the test body 10, the damaged portion 2 of the test bodies 95 and 96, and the soundness. There is a lag of about 40 minutes in the time zone in which the surface temperature difference appears in the part 3. The time difference “40 minutes” is based on this result. The significance probability of the above equation (1) is 0.05 or less. Therefore, the present inventor has determined that there is no problem even if a prediction formula for each damage distinction is created by using the non-standardized coefficient B.

  The personal computer 80 stores a temperature difference td that can be detected by an infrared camera in advance. Then, the calculated temperature difference (t) is compared with the stored temperature difference td, and when the temperature difference (t) falls below the temperature difference td, it is determined that the infrared camera can shoot, and the public communication line 85 is connected. An e-mail indicating the end of the shooting period is sent.

  The temperature difference td varies depending on the type of infrared camera. For this reason, in this embodiment, the temperature difference td is set for each investigation by the infrared camera. A method for setting the temperature difference td will be described later. If the infrared camera is a specific one, a specific temperature difference td may be set.

  On the monitor device 80a of the personal computer 80, various data of the specimens 60 and 60 'and the temperature difference (t) obtained by the above equation (1) are displayed.

[Installation of specimen]
Next, the installation method of the test bodies 60 and 60 'will be described.
The test body 60 is for judging the survey time of the wall height column 21 and is installed in a temperature environment equivalent to the wall height column 21 of the bridge 20. Since the wall height section 21 of the bridge 20 has a relatively large amount of sunlight and is well-ventilated, the test specimen 60 for the sun is installed near the bridge 20 on the ground where there is the same amount of sunlight and is well-ventilated. The

  By the way, the temperature environment of the wall height column 21 varies depending on the direction of the wall height column 21. For example, the wall height column 21 on the south surface rises greatly in the morning and gradually decreases in the afternoon. The wall height column 21 on the west surface gradually rises in the morning and rises greatly in the afternoon. In this way, the temperature environment varies depending on the direction even with the same sun. Therefore, the test body 60 is installed corresponding to the direction of the wall rail 21. In the present embodiment, two test bodies 60 and 60 are prepared corresponding to the wall height columns 21 on the south surface and the west surface.

  When searching for the installation location of the test body 60, the test body 60 is placed at appropriate locations on the west and south sides of the bridge 20, and the temperature data of the radiation thermometer 62 and the radiation thermometer 63 are compared. If the temperature data of the radiation thermometer 62 and the radiation thermometer 63 at the place are substantially the same, the test body 60 is installed at the place. If the temperature data of the radiation thermometer 62 and the radiation thermometer 63 do not match, the test body 60 is placed in another place, and the temperature data of the radiation thermometer 62 and the radiation thermometer 63 are compared again. In this way, the temperature environment of the test body 60 is made equal to the temperature environment of the wall height section 21 of the bridge 20.

  The test body 60 ′ is for judging the investigation time of the floor slab part 23, and is installed in a temperature environment equivalent to the floor slab part 23 of the bridge 20. Since the floor slab portion 23 of the bridge 20 is in an environmental condition where there is no solar radiation, the shade specimen 60 'is installed on the ground near the bridge 20 and with little solar radiation.

  When searching for the installation location of the test body 60 ′, the test body 60 ′ is placed at an appropriate location around the base of the bridge 20, and the temperature data of the radiation thermometer 62 and the radiation thermometer 63 are compared. If the temperature data of the radiation thermometer 62 and the radiation thermometer 63 at the place are substantially the same, the test body 60 'is installed at the place. If the temperature data of the radiation thermometer 62 and the radiation thermometer 63 do not match, the test body 60 'is placed in another place, and the temperature data of the radiation thermometer 62 and the radiation thermometer 63 are compared again. Thus, the temperature environment of the test body 60 ′ is made equal to the temperature environment of the floor slab portion 23 of the bridge 20.

[Infrared survey procedure]
Next, an infrared survey procedure will be described.
The researcher identifies the survey date from weather forecasts and past weather data. The investigator transmits an e-mail in the measurement mode ON by the electronic communication device 81 several hours before the investigation by the infrared camera. The measurement mode ON e-mail is transmitted to the specimens 60 and 60 ′ via the personal computer 80. Usually, when the investigation by the infrared camera is not performed, the time interval of temperature / humidity detection is made long to save power. On the other hand, when investigating with an infrared camera, the temperature / humidity detection time interval is shortened. By shortening the time interval of temperature / humidity detection, the survey timing can be judged more accurately. The test bodies 60, 60 'shorten the temperature / humidity detection time interval in response to the reception of the measurement mode ON e-mail. The temperature data of the radiation thermometers 61 and 62 of the test body 60 and the condensation data of the condensation sensor 64 are transmitted to the personal computer 80. The temperature data of the radiation thermometers 61 and 62 of the test body 60 ′ and the dew condensation data of the temperature / humidity sensor 71 are transmitted to the personal computer 80. Each data is displayed on the monitor device 80a of the personal computer 80.

  Usually, shooting with an infrared camera starts in the morning. From the results shown in FIGS. 14 (a) and 14 (b), the time zone in which the surface temperature of the cavity of the test specimen differs from the surface temperature of the concrete filling portion shows a difference in the surface temperature of the damaged portion and the healthy portion to be investigated. It is known that it is slightly behind the time zone. Therefore, the timing for starting the examination photographing is made after a difference between the surface temperature of the cavity 12 of the test specimens 60 and 60 ′ and the surface temperature of the concrete filling part 13 occurs. By doing so, it is possible to avoid a situation in which the investigation is performed in a state where there is no difference between the surface temperature of the damaged portion 2 to be investigated of the bridge 20 and the surface temperature of the healthy portion 3.

  At the start of the investigation, the investigator photographs the surface of the cube 11 of the specimen 60 (or specimen 60 ') with an infrared camera. When the hollow portion 12 and the concrete filling portion 13 of the test body 60 can be discriminated from the image of the infrared camera, an electronic mail indicating the start of photographing is transmitted to the personal computer 80 by the electronic communication device 81. Then, the bridge 20 is photographed with an infrared camera.

  An e-mail indicating the start of shooting is received by the personal computer 80. The personal computer 80 stores the surface temperature difference between the cavity portion 12 and the concrete filling portion 13 of the test body 60 at this time as a temperature difference td that can be detected by an infrared camera. Temperature data and humidity data are transmitted to the personal computer 80 from the test bodies 60 and 60 'every moment. The personal computer 80 predicts and calculates the temperature difference (t) between the surface temperature of the damaged portion 2 of the bridge 20 and the surface temperature of the healthy portion 3 using the above equation (1). The temperature difference (t) is calculated for each of the floats 95a to 95c and 96a to 96c shown in FIG.

  If any of the predicted temperature differences (t) falls below the stored temperature difference td, the difference between the surface temperature of the damaged portion 2 of the bridge 20 and the surface temperature of the healthy portion 3 is becoming smaller, and the infrared camera There is a possibility that the captured image cannot be distinguished from each other. Accordingly, the personal computer 80 determines that the photographing end time has come when any temperature difference (t) falls below the stored temperature difference td. Then, an e-mail indicating the end of the photographing time is transmitted to the investigator's electronic communication device 81.

  An electronic mail indicating the end of the shooting time is received by the electronic communication device 81. In response to the reception of the e-mail, the electronic communication device 81 informs that the damaged portion 2 and the healthy portion 3 cannot be identified by the infrared camera by using a warning sound, a warning light, or a warning message. The investigator ends the investigation with the infrared camera when confirming this warning. The investigator transmits an e-mail in the measurement mode OFF using the electronic communication device 81. The measurement mode OFF e-mail is transmitted to the specimens 60 and 60 ′ via the personal computer 80. The test bodies 60 and 60 'extend the temperature / humidity detection time interval in response to reception of the measurement mode OFF e-mail.

  By the way, dew condensation may occur on the surface of the sunny wall height column 21. When condensation occurs, it becomes difficult to produce a difference between the surface temperature of the damaged part 2 and the surface temperature of the healthy part 3. At this time, condensation also occurs on the surface of the cube 11 of the test body 60. When dew condensation is detected by the dew condensation sensor 64, an e-mail indicating the occurrence of dew condensation is transmitted from the test body 60 to the personal computer 80. The personal computer 80 transmits an e-mail indicating the occurrence of condensation to the electronic communication device 81 of the investigator. An electronic mail indicating the occurrence of condensation is received by the electronic communication device 81. In response to the reception of the e-mail, the electronic communication device 81 informs that the damaged portion 2 and the healthy portion 3 cannot be identified by the infrared camera by using a warning sound, a warning light, or a warning message. The investigator stops or terminates the investigation by the infrared camera when confirming this warning.

  As shown in FIG. 14, the time when the temperature difference disappears when the damage is a cavity is later than the time when the temperature difference disappears when the damage is floating. Therefore, if the photographing by the infrared camera is terminated when the temperature difference of the float is no longer generated, the float / peeling and the cavity can be reliably detected by the infrared shark. Therefore, the reliability of the survey results is improved.

[Other forms]
For example, the personal computer 80 may be a laptop personal computer, and an investigator may carry the personal computer 80. In this case, the electronic communication device 81 is not necessary, and communication means and communication operation between the personal computer 80 and the electronic communication device 81 are not necessary. That is, an e-mail indicating the start of shooting is not necessary, and the investigator only needs to perform an input operation for starting shooting on the personal computer 80. Furthermore, there is no need for an e-mail indicating the end of the shooting period, and the personal computer 80 may notify the investigator directly of a warning.

  The calculation using the above equation (1) and the comparison between the temperature difference (t) and the temperature difference t may be performed on the side of the specimens 60 and 60 ′. In this case, communication should be performed between the test bodies 60 and 60 'and the electronic communication device 81 of the investigator.

[Addition of damage pattern and temperature transition pattern]
In Example 1, the damage pattern and temperature transition pattern of the cavity are shown in FIG. In this embodiment, it is assumed that the damage is floating. FIG. 21 shows the correspondence between the damage pattern including floating and the temperature transition pattern. Like Example 1, based on the table | surface of FIG. 21, the damage state of a site | part to be investigated can be judged.

  In the above description, the description has been made assuming a concrete structure such as a bridge. However, the present invention is not limited to a concrete structure, and there is a possibility that damage may occur inside. Any structure that can be captured as a difference can be applied to any structure such as a tile or a brick. The present invention has been described on the assumption that a concrete structure is a bridge, an elevated structure, or the like, but the present invention can naturally be applied to a case where buildings, general houses, and the like are to be investigated.

FIGS. 1A and 1B are diagrams showing a difference in temperature between a damaged part and a healthy part inside a concrete structure in the daytime and at night. FIG. 2 is a graph showing temperature changes of the outside air temperature, the damaged part, and the healthy part. FIG. 3 is a perspective view showing the structure of the test body 60. FIG. 4 is a diagram showing the installation location of the test specimen. FIGS. 5A, 5B, 5C, and 5D are graphs showing the outside air temperature and the temperature change of the damaged part and the healthy part for each season. FIG. 6 is a table showing the correspondence between the season and time zone and the time available for photographing by the infrared camera. FIG. 7 is a graph illustrating a time zone suitable for photographing in one day. FIG. 8 is a table showing a correspondence relationship between the damage pattern and the actual damage situation, the necessity of the hit sound investigation, and the priority. FIGS. 9A and 9B are diagrams used for explaining the FEM analysis model. FIG. 10 is a table showing the correspondence between the damage pattern, the FEM analysis model, the temperature distribution image of the concrete surface photographed by the infrared camera, and the temperature line graph. FIG. 11 is a table showing the correspondence between the damage pattern and the temperature transition pattern. FIG. 12 is a diagram used to explain how a temperature line graph is created from an infrared image. FIGS. 13A and 13B are views for explaining a specimen having a float. FIG. 14A is a graph showing the experimental result of the damage pattern 1, and FIG. 14B is a graph showing the experimental result of the damage pattern 2. FIG. 15 is a diagram showing an outline of a structure temperature environment monitoring system and an imaging time notification system. FIG. 16A is a front view of the test specimen 60 for Hinata, and FIG. 16B is a side view of the test specimen 60 for Hyuga. FIG. 17A is a front view of a shade specimen 60 ′, and FIG. 17B is a side view of the shade specimen 60 ′. FIG. 18 is a block diagram of the test body 60 for Hinata. FIG. 19 is a block diagram of the shade 60 '. FIG. 20 is a table showing each non-standardized coefficient for each damage pattern. FIG. 21 is a table showing the correspondence between the damage pattern and the temperature transition pattern.

Explanation of symbols

DESCRIPTION OF SYMBOLS 20 ... Bridge 21 ... Wall height column part 23 ... Floor slab part 60, 60 '... Test body 61, 62, 63 ... Radiation thermometer 64 ... Condensation sensor 65 ... Data recording device 66 ... Communication apparatus 67 ... Antenna 71 ... Temperature / humidity sensor 80 ... PC 80 ... Monitor device 81 ... Electronic communication device 85 ... Public communication line

Claims (8)

In the structure investigation method using an infrared camera, the surface of the structure is photographed with an infrared camera, and the damage state inside the structure is investigated based on the temperature distribution of the photographed structure surface.
A test body having a damaged part including damage inside and a healthy part not including damage inside, a temperature sensor for a damaged part for detecting a surface temperature of the damaged part among the surfaces of the test body, and a surface of the test body A temperature sensor for a healthy part for detecting the surface temperature of the healthy part and a temperature sensor for a structure for detecting the surface temperature of a predetermined part of the structure,
The test body is disposed at a position where the detection temperature of the temperature sensor for the structure and the detection temperature of the temperature sensor for the healthy part are substantially the same,
When the difference between the detected temperature of the damaged part temperature sensor and the detected temperature of the healthy part temperature sensor is equal to or greater than a predetermined value, the part to be investigated of the structure is imaged by the infrared camera. Structure survey method. In the structure investigation method using an infrared camera, the surface of the structure is photographed with an infrared camera, and the damage state inside the structure is investigated based on the temperature distribution of the photographed structure surface.
A test body having a damaged part including damage inside and a healthy part not including damage inside, a temperature sensor for a damaged part for detecting a surface temperature of the damaged part among the surfaces of the test body, and a surface of the test body A healthy part temperature sensor for detecting the surface temperature of the healthy part and an outside air temperature sensor for detecting outside air,
The test body is installed around the structure,
Photograph the surface of the structure with an infrared camera,
The difference between the detected temperature of the damaged portion temperature sensor and the detected temperature of the healthy portion temperature sensor, the expected average temperature on the day of shooting, the detected temperature of the outside air temperature sensor, and the detection of the outside air temperature sensor a predetermined time ago The difference between the temperature and the surface temperature of the damaged part of the structure and the surface temperature of the healthy part are predicted every predetermined time ,
When the predicted temperature difference falls below a predetermined temperature difference that can distinguish between a damaged part and a sound part of a structure by an infrared camera image, the infrared camera is used to end the imaging of the structure. Structure survey method. Prepare a temperature sensor for a structure that detects the surface temperature of a predetermined part of the structure,
The structure inspection by the infrared camera according to claim 2, wherein the test body is installed at a position where the detection temperature of the temperature sensor for the structure and the detection temperature of the temperature sensor for the healthy part are substantially the same. Method. Before the structure is photographed by the infrared camera, the surface of the damaged part and the healthy part of the specimen are photographed by the infrared camera, and the temperature sensor for the damaged part is detected when the damaged part and the healthy part can be distinguished by the infrared camera. The method for investigating a structure using an infrared camera according to claim 2, wherein a difference between a temperature and a temperature detected by the temperature sensor for the healthy part is stored as the predetermined temperature difference . In a structure photographing time notification system for photographing the structure end time when photographing the surface of the structure with an infrared camera and investigating the damage state inside the structure based on the temperature distribution of the photographed structure surface ,
A test body of a structure having a damaged part including damage inside and a healthy part including no damage inside;
A temperature sensor for a damaged portion that detects the surface temperature of the damaged portion of the surface of the test body; and
A temperature sensor for a healthy part that detects the surface temperature of the healthy part of the surface of the test body; and
An outside air temperature sensor for detecting the outside air temperature;
A temperature difference storage means for storing a predetermined temperature difference capable of distinguishing a damaged part and a healthy part of a structure from an image of an infrared camera ;
The difference between the detected temperature of the damaged portion temperature sensor and the detected temperature of the healthy portion temperature sensor, the expected average temperature on the day of shooting, the detected temperature of the outside air temperature sensor, and the detection of the outside air temperature sensor a predetermined time ago A temperature difference prediction means for predicting the difference between the surface temperature of the damaged part of the structure and the surface temperature of the healthy part at predetermined time intervals using the difference between the temperature and
An end signal output means for outputting a photographing end signal when the temperature difference predicted by the temperature difference prediction means falls below a predetermined temperature difference stored in the temperature difference storage means;
An imaging timing notification system for a structure, comprising: an end timing notifying means for notifying that the imaging possible time of the infrared camera has ended when the imaging end signal is input. 6. The structure according to claim 5, further comprising communication means for transmitting temperature data relating to a detected temperature from the damaged part temperature sensor and the healthy part temperature sensor to the temperature difference prediction means via a communication line. An object shooting time information system. The end time notification means includes a portable electronic communication device,
6. The structure photographing time notification system according to claim 5, further comprising communication means for transmitting a photographing end signal from the temperature difference predicting means to the electronic communication device via a communication line. Whether the temperature distribution on the surface of the structure is in a state suitable for investigation, which is used when photographing the surface of the structure with an infrared camera and investigating the damage state inside the structure based on the temperature distribution on the photographed structure surface In order to determine whether or not, in the test body of the structure having a damaged portion including damage inside and a healthy portion not including damage inside, which is imitated to the structure,
A temperature sensor for a damaged portion for detecting a surface temperature of the damaged portion;
A healthy part temperature sensor for detecting the surface temperature of the healthy part;
A temperature sensor for a structure for detecting a surface temperature of a predetermined part of the structure;
A dew condensation sensor that detects dew condensation on the surface of the structure;
Data transmission for transmitting temperature data related to detection temperatures of the damaged part temperature sensor, the healthy part temperature sensor, and the structure temperature sensor, and a signal indicating that condensation has been detected by the condensation sensor via a communication line And
A test body for a structure, comprising: a temperature sensor for the damaged part, a temperature sensor for the healthy part, and a data recording part for recording temperature data relating to a temperature detected by the temperature sensor for the structure.

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