Structure evaluation system, structure evaluation method, and structure evaluation device

Abstract

To provide a structure evaluation system, a structure evaluation method, and a structure evaluation device, which can evaluate the deterioration state of a structure without locating the position of an elastic wave source.SOLUTION: A structure evaluation system includes a plurality of sensors, a vehicle number estimation unit, and an evaluation unit. The plurality of sensors detect elastic waves generated inside a structure. The vehicle number estimation unit estimates the number of vehicles passing through the structure on the basis of a plurality of elastic waves detected by each of the plurality of sensors. The evaluation unit evaluates the deterioration state of the structure using vehicle information relating to the number of vehicles estimated by the vehicle number estimation unit.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] An embodiment of the present invention relates to a structure evaluation system, a structure evaluation method, and a structure evaluation device. [Background technology]

[0002] By installing a sensor on the surface of a structure such as a bridge, it is possible to detect elastic waves generated inside the structure. Furthermore, by installing multiple sensors on the surface of the structure, it is possible to locate the position of the source of the elastic waves (hereinafter referred to as the "elastic wave source") based on the difference in arrival time of the elastic waves detected by each sensor. Elastic waves are also generated inside the structure when an impact is applied to the surface of the structure from the outside. In such cases, too, it is possible to locate the position of the elastic wave source based on the difference in arrival time of the elastic waves detected by each sensor.

[0003] When there is damage to the propagation path of elastic waves inside a structure, the propagation of the elastic waves is impeded. When the propagation of elastic waves is impeded due to damage inside the structure, some sensors cannot detect the elastic waves. As a result, the accuracy of the location results of the elastic wave source is reduced. When a spatially uniform impact, such as the impact of raindrops on a road surface during rainfall, is applied to the surface of a structure and elastic waves are detected by sensors installed on opposite sides, a decrease in the density of elastic wave sources is observed in areas with internal damage. By utilizing such characteristics, the deterioration state of a structure (presence or absence of damage inside the structure) can be evaluated. In particular, damage inside the structure can be detected using elastic waves generated by vehicles traveling on the road surface.

[0004] However, when performing evaluation using the above method, it is necessary to locate the position of the elastic wave source. The processing load increases as the amount of measurement data increases due to the calculation of position location. In addition, since there is no unique calculation method for position location, the results may vary depending on the calculation conditions, etc. Therefore, there is a demand for an evaluation method that can evaluate the deterioration state of a structure without locating the position of the elastic wave source. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] International Publication No. 2017 / 217034 [Patent Document 2] International Publication No. 2020 / 194494 Summary of the Invention [Problem to be solved by the invention]

[0006] The problem to be solved by the present invention is to provide a structure evaluation system, a structure evaluation method, and a structure evaluation device that can evaluate the deterioration state of a structure without locating the position of an elastic wave source. [Means for solving the problem]

[0007] The structure evaluation system of the embodiment has a plurality of sensors, a vehicle number estimation unit, and an evaluation unit. The plurality of sensors detect elastic waves generated inside the structure. The vehicle number estimation unit estimates the number of vehicles that have passed through the structure based on the plurality of elastic waves detected by each of the plurality of sensors. The evaluation unit evaluates the deterioration state of the structure using vehicle information related to the number of vehicles estimated by the vehicle number estimation unit. [Brief description of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing a configuration of a structure evaluation system according to a first embodiment. [Diagram 2] FIG. 2 is a diagram showing an example of the configuration of a signal processing unit according to the first embodiment. [Diagram 3] FIG. 2 is a diagram showing an example of an arrangement of a plurality of sensors according to the first embodiment. [Figure 4] FIG. 4 is a diagram for explaining a process of estimating the number of passing vehicles in the first embodiment. [Figure 5A] FIG. 13 represents a histogram obtained based on a healthy structure. [Figure 5B]FIG. 13 shows a histogram obtained based on a structure that has undergone some degree of deterioration. [Figure 5C] FIG. 13 shows a histogram obtained based on a structure that has undergone some degree of deterioration. [Figure 6] FIG. 2 is a sequence diagram showing the flow of a deterioration state evaluation process performed by the structure evaluation system in the first embodiment. [Figure 7A] FIG. 13 illustrates a histogram of the cumulative number of vehicles obtained based on healthy structures. [Figure 7B] FIG. 13 is a histogram of the cumulative number of vehicles obtained based on structures that have deteriorated to a certain degree. [Figure 7C] FIG. 13 is a histogram of the cumulative number of vehicles obtained based on structures that have deteriorated to a certain degree. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] Hereinafter, a structure evaluation system, a structure evaluation method, and a structure evaluation device according to embodiments will be described with reference to the drawings. (First embodiment) 1 is a diagram showing the configuration of a structure evaluation system 100 in the first embodiment. The structure evaluation system 100 is used to evaluate the soundness of a structure 50. In the following description, evaluation means determining the degree of soundness of the structure 50, i.e., the deterioration state of the structure 50, based on a certain criterion.

[0010] In the following description, the structure 50 is a bridge, but the structure 50 does not have to be limited to a bridge. The structure 50 may be any structure in which elastic waves 11 are generated due to the occurrence or growth of a crack, or an external impact (e.g., rain, artificial rain, etc.). Note that bridges are not limited to structures erected over rivers, valleys, etc., but also include various structures (e.g., highway viaducts) that are installed above the ground.

[0011] Damage that affects the evaluation of the deterioration state of the structure 50 includes damage inside the structure that impedes the propagation of elastic waves 11, such as cracks, cavities, and sedimentation. Here, the cracks include vertical cracks, horizontal cracks, and diagonal cracks. A vertical crack is a crack that occurs in a direction perpendicular to the road surface. A horizontal crack is a crack that occurs in a direction horizontal to the road surface. A diagonal crack is a crack that occurs in a direction other than horizontal and vertical to the road surface. Sedimentation is a deterioration in which concrete turns into sediment, mainly at the boundary between the asphalt and the concrete deck.

[0012] The structure evaluation system 100 includes a plurality of sensors 20-1 to 20-n (n is an integer equal to or greater than 2), a signal processing unit 30, and a structure evaluation device 40. Each of the plurality of sensors 20-1 to 20-n and the signal processing unit 30 are connected to each other via wires so as to be able to communicate with each other. The signal processing unit 30 and the structure evaluation device 40 are connected to each other so as to be able to communicate with each other via wires or wirelessly. In the following description, when there is no need to distinguish between the sensors 20-1 to 20-n, they will be referred to as sensors 20.

[0013] As shown in Fig. 1, when a vehicle 10 passes over a structure 50, a load is applied to the road surface due to contact between the running parts (e.g., tires) of the vehicle 10 and the road surface. A large number of elastic waves 11 are generated inside the structure 50 due to deflection, strain, and interaction between the running parts and the pavement caused by the load. Each sensor 20 installed on the underside of the structure 50 can detect the elastic waves 11 generated inside the structure 50.

[0014] The sensor 20 has a piezoelectric element and detects the elastic wave 11 generated from inside the structure 50. The sensor 20 is installed at a position where it can detect the elastic wave 11 on the surface of the structure 50. For example, the sensors 20-1 to 20-n are installed on any one of the road surface, side surface, and bottom surface at equal or different intervals in the vehicle travel axis direction and the vehicle travel axis perpendicular direction. The vehicle travel axis direction refers to the direction in which the vehicle travels on the road surface. The vehicle travel axis perpendicular direction refers to the direction perpendicular to the vehicle travel axis direction. The sensor 20 converts the detected elastic wave 11 into an electric signal. In the following description, a case where the sensor 20 is installed on the bottom surface of the structure 50 will be described as an example.

[0015] For example, a piezoelectric element having sensitivity in the range of 10 kHz to 1 MHz is used for the sensor 20. There are various types of sensors 20, such as a resonance type having a resonance peak within a frequency range and a wideband type with suppressed resonance, but any type of sensor 20 may be used. The method of the sensor 20 detecting the elastic wave 11 includes a voltage output type, a resistance change type, and a capacitance type, but any detection method may be used.

[0016] An acceleration sensor may be used instead of the sensor 20. In this case, the acceleration sensor detects the elastic waves 11 generated inside the structure 50. Then, the acceleration sensor performs the same process as the sensor 20 to convert the detected elastic waves 11 into an electrical signal.

[0017] The signal processing unit 30 receives the electrical signal output from the sensor 20. The signal processing unit 30 performs signal processing on the input electrical signal. The signal processing performed by the signal processing unit 30 includes, for example, noise removal and extraction of elastic wave features. The signal processing unit 30 generates transmission data including a digital signal after signal processing. The signal processing unit 30 outputs the generated transmission data to the structure evaluation device 40.

[0018] The signal processing unit 30 is configured using an analog circuit or a digital circuit. When the signal processing unit 30 is configured using an analog circuit, an analog-digital converter does not need to be provided between the sensor 20 and the signal processing unit 30. In other words, when the signal processing unit 30 is configured using an analog circuit, an electric signal from which noise has been removed by a filter is input to the signal processing unit 30. The digital circuit is realized, for example, by an FPGA (Field Programmable Gate Array) or a microcomputer. The digital circuit may also be realized by a dedicated LSI (Large-Scale Integration). The signal processing unit 30 may also be equipped with a non-volatile memory such as a flash memory or a removable memory. In the following description, a case where the signal processing unit 30 is configured using a digital circuit will be described.

[0019] 2 is a diagram showing an example of the configuration of the signal processing unit 30 in the first embodiment. The signal processing unit 30 includes an amplifier 301, an A / D converter 302, a waveform shaping filter 303, a gate generation circuit 304, an arrival time determination unit 305, a feature extraction unit 306, a data recording unit 307, a memory 308, and a vehicle number estimation unit 309.

[0020] The amplifier 301 amplifies the electrical signal output from the sensor 20, and outputs the amplified electrical signal to the A / D converter 302. The amplifier 301 amplifies the electrical signal by a predetermined amount (for example, 10 to 100 times), for example.

[0021] The A / D converter 302 quantizes the amplified electrical signal and converts it into a digital signal. The A / D converter 302 outputs the digital signal to the waveform shaping filter 303.

[0022] The waveform shaping filter 303 removes noise components outside a predetermined band from the input digital signal. The waveform shaping filter 303 is, for example, a digital band pass filter (BPF). The waveform shaping filter 303 outputs the digital signal after the noise components have been removed (hereinafter referred to as the “noise-removed signal”) to the gate generation circuit 304 and the feature extraction unit 306.

[0023] The gate generation circuit 304 receives the noise removal signal output from the waveform shaping filter 303. The gate generation circuit 304 generates a gate signal based on the input noise removal signal. The gate signal is a signal that indicates whether the waveform of the noise removal signal is sustained or not.

[0024] The gate generation circuit 304 is realized by, for example, an envelope detector and a comparator. The envelope detector detects the envelope of the noise-removed signal. The envelope is extracted, for example, by squaring the noise-removed signal and performing a predetermined process (for example, a process using a low-pass filter or a Hilbert transform) on the squared output value. The comparator determines whether the envelope of the noise-removed signal is equal to or greater than a predetermined threshold.

[0025] When the envelope of the noise-removed signal is equal to or greater than a predetermined threshold, the gate generation circuit 304 outputs a first gate signal indicating that the waveform of the noise-removed signal is sustained to the arrival time determination unit 305 and the feature extraction unit 306. On the other hand, when the envelope of the noise-removed signal is less than a predetermined threshold, the gate generation circuit 304 outputs a second gate signal indicating that the waveform of the noise-removed signal is not sustained to the arrival time determination unit 305 and the feature extraction unit 306. Note that, although the gate generation circuit 304 has been configured to determine whether the waveform of the noise-removed signal is sustained based on the envelope, the gate generation circuit 304 may process the noise-removed signal itself or a signal to which an absolute value is applied. The threshold used for this gate generation is referred to as a measurement threshold.

[0026] The arrival time determination unit 305 receives as input a clock output from a clock source such as a crystal oscillator (not shown) and a gate signal output from the gate generation circuit 304. The arrival time determination unit 305 determines the elastic wave arrival time using the clock input while the first gate signal is being input. The arrival time determination unit 305 outputs the determined elastic wave arrival time to the data recording unit 307 as time information. The arrival time determination unit 305 does not perform processing while the second gate signal is being input. The arrival time determination unit 305 generates cumulative time information from the time of power-on based on the signal from the clock source. Specifically, the arrival time determination unit 305 may be a counter that counts edges of the clock, and the value of the register of the counter may be the time information. The register of the counter is determined to have a predetermined bit length.

[0027] The feature extraction unit 306 receives the noise-removed signal output from the waveform shaping filter 303 and the gate signal output from the gate generation circuit 304. The feature extraction unit 306 extracts the feature of the noise-removed signal by using the noise-removed signal input while the first gate signal is input. The feature extraction unit 306 does not perform processing while the second gate signal is input. The feature is information indicating the feature of the noise-removed signal. In other words, the feature of the noise-removed signal is the feature of the elastic wave detected by the sensor 20.

[0028] The feature amount is, for example, the amplitude [mV] of the waveform, the rise time [usec] of the waveform, the duration [usec] of the gate signal, the number of zero cross counts [times], the energy [arb.] of the waveform, the frequency [Hz], and the root mean square (RMS) value. The feature amount extraction unit 306 outputs the parameters related to the extracted feature amount to the data recording unit 307. When outputting the parameters related to the feature amount, the feature amount extraction unit 306 associates the parameters related to the feature amount with a sensor ID. The sensor ID represents identification information for identifying the sensor 20 installed in the area (hereinafter referred to as the "evaluation area") that is the target of the evaluation of the soundness of the structure 50. This makes it possible to distinguish which sensor 20 detected the parameters related to the feature amount.

[0029] The amplitude of the waveform is, for example, the maximum amplitude value in the noise elimination signal. The rise time of the waveform is, for example, the time T1 from when the gate signal starts to rise until the noise elimination signal reaches its maximum value. The duration of the gate signal is, for example, the time from when the gate signal starts to rise until the amplitude becomes smaller than a preset value. The zero cross count is, for example, the number of times the noise elimination signal crosses a reference line that passes through a zero value.

[0030] The energy of the waveform is, for example, a value obtained by integrating the squared amplitude of the noise-removing signal at each time point over time. The definition of the energy is not limited to the above example, and may be, for example, an approximation using the envelope of the waveform. The frequency is the frequency of the noise-removing signal. The RMS value is, for example, a value obtained by squaring the amplitude of the noise-removing signal at each time point and taking the square root.

[0031] The data recording unit 307 receives the sensor ID, time information, and parameters related to the feature amount as input. The data recording unit 307 records the elastic wave data including the input sensor ID, time information, and parameters related to the feature amount in the memory 308. For example, the data recording unit 307 may record the elastic wave data in the memory 308 in the order in which it was acquired, or may record the elastic wave data in the memory 308 in chronological order based on the time information.

[0032] The memory 308 stores one or more pieces of elastic wave data. The memory 308 is, for example, a dual-port RAM (Random Access Memory). One piece of elastic wave data is data obtained from one elastic wave.

[0033] The vehicle number estimation unit 309 estimates the number of passing vehicles using one or more elastic wave data stored in the memory 308. More specifically, the vehicle number estimation unit 309 extracts elastic wave features included in each of the one or more elastic wave data. The vehicle number estimation unit 309 calculates the time series transition of the feature of each extracted elastic wave. The time series transition of the feature represents the transition of the feature of each elastic wave during the period from when the first gate signal is input to when the second gate signal is input. The time series transition of the feature is a mountain shape in which the feature reaches a peak at the timing when the traveling part of the vehicle 10 passes close to the sensor 20. Depending on conditions such as the type of the vehicle 10 and the traveling position, two peaks, one for the front wheels and one for the rear wheels, may be observed. The vehicle number estimation unit 309 estimates the number of passing vehicles based on the time series transition of the calculated feature.

[0034] Furthermore, the vehicle number estimation unit 309 calculates the number of sensors 20 that detect elastic waves generated by the passage of the same vehicle (hereinafter referred to as the "number of simultaneous sensor hits"). When the structure 50 is sound, all of the sensors 20 can detect elastic waves generated by the passage of a vehicle. Therefore, the number of simultaneous sensor hits is expected to be the number of all of the sensors 20 installed in the structure 50. On the other hand, when some damage occurs inside the structure 50, the damage prevents the propagation of elastic waves. Therefore, the sensor 20 installed near the area where the damage occurs may not be able to detect the elastic waves. This means that the more severe the damage inside the structure 50, the more sensors 20 that cannot detect elastic waves. In this way, the number of simultaneous sensor hits is an index for evaluating the deterioration state of the structure 50.

[0035] The vehicle number estimation unit 309 transmits information on the estimated number of passing vehicles (hereinafter referred to as the "estimated vehicle number") and information on the number of simultaneous sensor hits obtained for each passing vehicle as vehicle information to the structure evaluation device 40. The vehicle number estimation unit 309 may transmit vehicle information for the period to be evaluated (hereinafter referred to as the "evaluation period") collectively to the structure evaluation device 40, or may transmit the vehicle information to the structure evaluation device 40 each time vehicle information is obtained or each time a predetermined number of vehicle information is obtained.

[0036] Continuing the explanation by returning to Fig. 1, the structure evaluation device 40 includes a communication unit 41, a control unit 42, a storage unit 43, and a display unit 44.

[0037] The communication unit 41 receives one or more pieces of vehicle information transmitted from the signal processing unit 30.

[0038] The control unit 42 controls the entire structure evaluation device 40. The control unit 42 is configured using a processor such as a CPU (Central Processing Unit) and a memory. The control unit 42 functions as an acquisition unit 421 and an evaluation unit 422 by executing a program.

[0039] Some or all of the functional units of the acquisition unit 421 and the evaluation unit 422 may be realized by hardware such as an ASIC (Application Specific Integrated Circuit), a PLD (Programmable Logic Device), or an FPGA, or may be realized by a combination of software and hardware. The program may be recorded on a computer-readable recording medium. The computer-readable recording medium is, for example, a non-transitory storage medium such as a portable medium such as a flexible disk, a magneto-optical disk, a ROM (Read Only Memory), or a CD-ROM, or a storage device such as a hard disk built into a computer system. The program may be transmitted via an electric communication line.

[0040] Some of the functions of the acquisition unit 421 and the evaluation unit 422 do not need to be pre-installed in the structure evaluation device 40, and may be realized by installing an additional application program in the structure evaluation device 40.

[0041] The acquisition unit 421 acquires various information. For example, the acquisition unit 421 acquires vehicle information received by the communication unit 41. The acquisition unit 421 acquires vehicle information for an evaluation target period. The acquisition unit 421 stores the acquired vehicle information in the storage unit 43.

[0042] The evaluation unit 422 evaluates the deterioration state of the structure 50 based on the vehicle information acquired by the acquisition unit 421. For example, the evaluation unit 422 evaluates the deterioration state of the structure 50 based on the shape of the distribution obtained based on the vehicle information or the peak position of the distribution. Here, the distribution obtained based on the vehicle information is a histogram with the horizontal axis representing the number of simultaneously hit sensors and the vertical axis representing the estimated number of vehicles. A specific evaluation method performed by the evaluation unit 422 will be described later.

[0043] The storage unit 43 stores the vehicle information for the evaluation period acquired by the acquisition unit 421 and the reference information. The reference information is information that the evaluation unit 422 refers to in order to perform the evaluation. For example, the reference information includes information on the shape of the distribution or the peak position of the distribution for determining whether the vehicle is healthy, and information on the shape of the distribution or the peak position of the distribution for determining whether deterioration has occurred. The storage unit 43 is configured using a storage device such as a magnetic hard disk device or a semiconductor storage device.

[0044] The display unit 44 displays the evaluation result under the control of the evaluation unit 422. For example, the display unit 44 may display whether or not deterioration has occurred inside the structure 50 as the evaluation result. The display unit 44 is an image display device such as a liquid crystal display or an organic EL (Electro Luminescence) display. The display unit 44 may be an interface for connecting an image display device to the structure evaluation device 40. In this case, the display unit 44 generates a video signal for displaying the evaluation result and outputs the video signal to the image display device connected to itself.

[0045] FIG. 3 is a diagram showing an example of the arrangement of a plurality of sensors 20 in the first embodiment. FIG. 3 shows an example in which 18 sensors 20-1 to 20-18 are arranged in a 3×6 grid. Here, the sensors 20 are numbered 1 to 18ch in order from the right side of FIG. 3. A vehicle 10 enters a structure from the right side of FIG. 3 and exits from the left side. Therefore, an elastic wave generated by the passage of the vehicle 10 is usually first detected by the sensors 20-1 to 20-3 arranged at the right end of FIG. 3, gradually detected by the sensors 20 on the left side, and finally detected by the sensors 20-16 to 20-18 arranged at the left end.

[0046] Fig. 4 is a diagram for explaining the process of estimating the number of passing vehicles in the first embodiment. In the example shown in Fig. 4, the time series transition of the feature amount based on the elastic waves detected by the 2ch sensor 20-2 located at the center of the right end and the 17ch sensor 20-17 located at the center of the left end is excerpted and shown among the 18 sensors 20 shown in Fig. 3. In Fig. 4, the horizontal axis indicates time t, and the vertical axis indicates the integrated value of the duration of the elastic waves detected per unit time. Note that the feature amount used here does not necessarily have to be the integrated duration, and other feature amounts such as energy and amplitude can be used in the same manner.

[0047] The line segment S1 shown in FIG. 4 represents the time series transition of the feature amount based on the elastic wave detected by the sensor 20-2, and the line segment S2 represents the time series transition of the feature amount based on the elastic wave detected by the sensor 20-17. Since the vehicle 10 passes over the structure 50 at a predetermined interval, the time series transition of a plurality of feature amounts appears according to the number of passing vehicles, as shown in FIG. 4. The mountain-shaped waveform representing the time series transition of the feature amount is observed first by the sensor 20-2 on the side where the vehicle 10 enters, as shown by the circle 55, and is observed a little later by the sensor 20-17 on the side where the vehicle 10 exits. Based on the arrangement interval of the sensors 20, the wheel base of the vehicle 10, and the traveling speed of the vehicle 10, the time difference when the same vehicle is observed by each sensor 20 can be calculated, and the same vehicle can be identified from the series of detected signals.

[0048] In the example shown in FIG. 4, the vehicle number estimation unit 309 estimates that four vehicles 10 have passed. Two line segments S1 are shown in the circle 55, which represent the time series transition of the feature amount based on the elastic wave detected by the sensor 20-2. As described above, this is due to the elastic waves generated by the front and rear wheels of the vehicle 10. In FIG. 4, only the sensor 20-2 and the sensor 20-17 are excerpted, but the time series transition of the feature amount should be shown for the number of sensors 20 that detected the elastic wave. Therefore, the vehicle number estimation unit 309 estimates the number of simultaneous hit sensors based on the time series transition of the feature amount. For example, the vehicle number estimation unit 309 counts the number of sensors 20 that detected the vehicle 10 in the time series transition of the feature amount within the circle 55. The vehicle number estimation unit 309 estimates the counted number as the number of simultaneous hit sensors. As shown in FIG. 3, when 18 sensors 20 are installed, the maximum number of simultaneous hit sensors is 18.

[0049] Next, a specific evaluation method performed by the evaluation unit 422 will be described with reference to Figures 5A, 5B, and 5C. The evaluation unit 422 generates a histogram (hereinafter referred to as a "simultaneous hit histogram") with the number of simultaneous hit sensors on the horizontal axis and the estimated number of vehicles on the vertical axis based on the vehicle information obtained from the signal processing unit 30. The simultaneous hit histogram is a compilation of the estimated number of vehicles for each number of simultaneous hit sensors. The number of simultaneous hit sensors also varies due to variations in vehicle types and vehicle passing positions, and the simultaneous hit histogram has a characteristic distribution.

[0050] FIG. 5A shows a histogram obtained based on a healthy structure 50, and FIG. 5B and FIG. 5C show histograms obtained based on a structure 50 that has deteriorated to some extent. In the healthy structure 50 shown in FIG. 5A, the number of simultaneous hit sensors has peaks at positions "1" and "18", showing a shape like a bathtub. In the healthy structure 50, elastic waves are easily propagated and easily reach the sensors 20. Therefore, it is considered that elastic waves caused by passing vehicles are often detected by almost all of the sensors 20. It is presumed that the peak on the side of the number of hit sensors "1" is due to the detection of the inclusion of elastic waves caused by a vehicle 10 that has passed a location far from the measurement target area, or other noise.

[0051] 5B and 5C, the propagation of elastic waves is hindered by damage or the like in the structure 50 that has deteriorated to some extent, and the number of sensors 20 that cannot adequately detect the vehicle 10 increases. As a result, the number of vehicles with a simultaneous hit sensor count of "18" is significantly reduced, and the peak of the histogram shifts to the side with fewer simultaneous hit sensors. Therefore, the evaluation unit 422 generates a histogram based on the vehicle information obtained from the signal processing unit 30, and can easily evaluate the deterioration state of the structure 50 based on the shape of the generated histogram or the position of the peak in the histogram.

[0052] 5A to 5C or information on peak positions in the histograms may be stored in the storage unit 43 in association with the evaluation results (healthy or deteriorated), and the evaluation unit 422 may compare the histogram shapes or peak positions in the histograms generated by the evaluation unit 422 with the reference information. In this case, the evaluation unit 422 may determine as the final evaluation result the evaluation result in which the generated histogram shapes are associated with the closest histograms, or the evaluation result in which the peak positions in the generated histograms are associated with the closest peak position information.

[0053] Fig. 6 is a sequence diagram showing the flow of the deterioration state evaluation process by the structure evaluation system 100 in the first embodiment. The process in Fig. 6 is executed, for example, in response to the vehicle 10 traveling through the structure 50 to be evaluated.

[0054] When the vehicle 10 travels over the structure 50 to be evaluated, the traveling part of the vehicle 10 comes into contact with the road surface. As a result, an elastic wave 11 is generated within the structure 50. Each of the multiple sensors 20 detects the elastic wave 11 generated within the structure 50 (step S101). Each of the multiple sensors 20 converts the detected elastic wave 11 into an electrical signal and outputs it to the signal processing unit 30 (step S102). The signal processing unit 30 receives the electrical signal output from each of the multiple sensors 20. The signal processing unit 30 performs signal processing such as amplification, conversion to a digital signal, and noise removal on each received electrical signal.

[0055] The arrival time determination unit 305 determines the arrival time of each digital signal after signal processing (step S103). Specifically, the arrival time determination unit 305 determines the elastic wave arrival time using the clock input while the first gate signal is being input. The arrival time determination unit 305 outputs the determined elastic wave arrival time to the data recording unit 307 as time information. The arrival time determination unit 305 performs this process for all input digital signals.

[0056] The feature extraction unit 306 of the signal processing unit 30 extracts a feature of the noise-removed signal, which is a digital signal input while the first gate signal is being input (step S104). The feature extraction unit 306 outputs parameters related to the extracted feature to the data recording unit 307. The data recording unit 307 stores the elastic wave data including the sensor ID, time information, and the parameters related to the feature in the memory 308 (step S105).

[0057] The vehicle number estimation unit 309 calculates the time series transition of the feature amount using one or more pieces of elastic wave data stored in the memory 308 (step S106). One piece of elastic wave data includes parameters related to the feature amount of the elastic wave 11 detected by one sensor 20 during the period when one vehicle 10 passed. Therefore, the vehicle number estimation unit 309 calculates the time series transition of the feature amount such as the line segments S1 and S2 shown in Fig. 4 for each piece of elastic wave data. The vehicle number estimation unit 309 executes the process of step S106 for the evaluation target period.

[0058] The vehicle number estimation unit 309 estimates the number of passing vehicles based on the calculated time series transition of the feature amount for the evaluation period (step S107). Furthermore, the vehicle number estimation unit 309 calculates the number of simultaneous hit sensors based on the calculated time series transition of the feature amount for the evaluation period (step S108). The vehicle number estimation unit 309 transmits information on the estimated number of vehicles and information on the number of simultaneous sensor hits as vehicle information to the structure evaluation device 40 (step S109).

[0059] The communication unit 41 of the structure evaluation device 40 receives the vehicle information output from the signal processing unit 30. The acquisition unit 421 acquires the vehicle information received by the communication unit 41. The acquisition unit 421 records the acquired vehicle information in the storage unit 43. The evaluation unit 422 generates a simultaneous hit histogram using the vehicle information for the evaluation target period stored in the storage unit 43 (step S110). The evaluation unit 422 evaluates the deterioration state of the structure using the generated simultaneous hit histogram (step S111). As a method for the evaluation unit 422 to evaluate the deterioration state of the structure, there is an evaluation method based on either the distribution shape or peak position of the simultaneous hit histogram as described above. Each evaluation method will be specifically described below as an example.

[0060] (Evaluated based on the distribution shape of the simultaneous hits histogram) For example, when the shape of the generated simultaneous hit histogram indicates a shape indicating soundness (for example, the bathtub shape shown in FIG. 5A), the evaluation unit 422 evaluates that the structure 50 is sound. Alternatively, the evaluation unit 422 compares the shape of the histogram included in the reference information with the generated simultaneous hit histogram, and evaluates that the structure 50 is sound when the shape of the generated histogram is closest to the histogram associated with the evaluation result of soundness. Here, the expression "the shape of the histogram is closest to the histogram associated with the evaluation result of soundness" means that the similarity between the shape of the generated histogram and the histogram associated with the evaluation result of soundness is the highest, or the similarity is equal to or greater than a threshold value.

[0061] On the other hand, for example, when the shape of the generated simultaneous hit histogram indicates deterioration (for example, the shape shown in FIG. 5B or 5C), the evaluation unit 422 evaluates that the structure 50 is deteriorated. Alternatively, the evaluation unit 422 compares the shape of the histogram included in the reference information with the generated simultaneous hit histogram, and evaluates that the structure 50 is deteriorated when the shape of the generated histogram is closest to the histogram associated with the deterioration evaluation result. Here, the fact that the shape of the histogram is closest to the histogram associated with the deterioration evaluation result means that the similarity between the shape of the generated histogram and the histogram associated with the deterioration evaluation result is the highest, or that the similarity is equal to or greater than a threshold value.

[0062] As described above, the reference information includes a plurality of histogram shapes associated with the evaluation results. For example, the reference information includes a plurality of histogram shapes associated with the evaluation results indicating soundness, a plurality of histogram shapes associated with the evaluation results indicating deterioration, and the like. Note that the shape of the histogram associated with the evaluation results indicating soundness and the shape of the histogram associated with the evaluation results indicating deterioration are not limited to one shape each, and a plurality of shapes may be included in the reference information. The evaluation unit 422 calculates the similarity between each histogram shape included in the reference information and the generated simultaneous hit histogram. Next, the evaluation unit 422 selects a histogram shape with the highest calculated similarity or a threshold value or more from among the histogram shapes included in the reference information. The evaluation unit 422 evaluates the structure 50 as sound when the evaluation result associated with the selected histogram shape is sound, and evaluates the structure 50 as deteriorated when the evaluation result associated with the selected histogram shape is deteriorated. When there are multiple selected histogram shapes, the evaluation unit 422 may select the one with the most evaluation results as the final evaluation result, or may present the results to the user to allow the user to make a final selection.

[0063] (Evaluated based on peak position of coincidence histogram) The evaluation unit 422 evaluates the structure 50 to be healthy, for example, when the peak position of the number of simultaneous hit sensors in the generated simultaneous hit histogram is close to the total number of the installed multiple sensors 20. Here, the position close to the total number may be the position of the value of the total number, or a position where the difference from the total number is less than a certain value (for example, the difference is "1" or "2"). For example, when the total number of the multiple sensors 20 is "18", the structure 50 is evaluated to be healthy when the peak position of the number of simultaneous hit sensors is at "18" or when the peak position of the number of simultaneous hit sensors is at "16" or "17". Note that the value for determining that the number is close to the total number is not limited to the above-mentioned value, and may be set appropriately.

[0064] Alternatively, the evaluation unit 422 compares the peak position information included in the reference information with the peak position of the number of simultaneous hit sensors in the simultaneous hit histogram, and evaluates the structure 50 to be healthy if the peak position of the number of simultaneous hit sensors is included in the value indicated by the peak position information associated with the evaluation result of health.

[0065] On the other hand, the evaluation unit 422 evaluates that the structure 50 is deteriorated, for example, when the peak position of the number of simultaneous hit sensors in the generated simultaneous hit histogram is not close to the total number of the installed multiple sensors 20 (i.e., when it is a position other than a position close to the total number of the installed multiple sensors 20 described above). Alternatively, the evaluation unit 422 compares the peak position information included in the reference information with the peak position of the number of simultaneous hit sensors in the simultaneous hit histogram, and evaluates that the structure 50 is deteriorated, if the peak position of the number of simultaneous hit sensors is included in the value indicated by the peak position information associated with the evaluation result of deterioration.

[0066] The evaluation unit 422 outputs the evaluation result to the display unit 44. The display unit 44 displays the evaluation result output from the evaluation unit 422 (step S112).

[0067] The structure evaluation system 100 configured as above has a plurality of sensors 20, a vehicle number estimation unit 309, and an evaluation unit 422. The plurality of sensors 20 detect elastic waves generated inside the structure 50. The vehicle number estimation unit 309 estimates the number of vehicles that have passed through the structure 50 based on the plurality of elastic waves detected by each of the plurality of sensors 20. The evaluation unit 422 evaluates the deterioration state of the structure 50 using vehicle information related to the number of vehicles estimated by the vehicle number estimation unit 309. This makes it possible to evaluate the deterioration state of the structure without locating the position of the elastic wave source.

[0068] Second embodiment In the second embodiment, a configuration is described in which the estimated number of passing vehicles is compared with a reference value, and the deterioration state of a structure is evaluated based on the closest threshold value. The system configuration and the configuration of each device in the second embodiment are the same as those in the first embodiment. The following description focuses on the differences from the first embodiment.

[0069] In the simultaneous hit histogram in the first embodiment, when the number of simultaneous hit sensors is small, it is highly likely that the elastic waves are not generated by the passage of the vehicle 10 but are noise. Therefore, by setting a threshold N for the number of simultaneous hit sensors, regarding estimated vehicles whose number of simultaneous hit sensors is less than the threshold N as noise, and accumulating the number of estimated vehicles whose number of simultaneous hit sensors is equal to or greater than the threshold N, the number of passing vehicles can be estimated with higher accuracy.

[0070] 7A to 7C are graphs plotting the number of estimated vehicles against the threshold N of the number of simultaneous hit sensors. FIG. 7A to FIG. 7C are histograms of the number of vehicles obtained by accumulating the number of estimated vehicles whose number of simultaneous hit sensors is equal to or greater than the threshold N in, for example, FIG. 5A to FIG. 5C, respectively. That is, FIG. 7A shows a histogram of the cumulative number of vehicles obtained based on a sound structure 50, and FIG. 7B and FIG. 7C show histograms of the cumulative number of vehicles obtained based on a structure 50 that has deteriorated to a certain degree. In the histogram of the cumulative number of vehicles, the horizontal axis shows the threshold N of the number of simultaneous hit sensors, and the vertical axis shows the number of estimated vehicles (in this embodiment, the number of vehicles obtained by accumulating the number of estimated vehicles). Therefore, when the threshold N=1, the number of all estimated vehicles including estimated vehicles and estimated noise is counted, and when the threshold N=18, the number of only estimated vehicles detected by all sensors 20 is counted. By appropriately setting the value of the threshold N of the number of simultaneous hit sensors, the number of vehicles that have passed through the measurement point can be accurately estimated.

[0071] When the structure 50 is healthy, the number of simultaneous hit sensors is large, so even if the threshold value N is set large, the cumulative number of vehicles is close to the actual number of passing vehicles (hereinafter referred to as the "measured number of vehicles"). In the example shown in FIG. 7A, the threshold value at which the cumulative number of vehicles (estimated number of vehicles on the vertical axis in FIG. 7A) and the actual number of vehicles are closest is 15. On the other hand, when the structure 50 is deteriorated, the number of simultaneous hit sensors is small even for a vehicle 10 that passes directly above the sensor 20, so in order to obtain an estimated number of vehicles close to the actual number of vehicles, it is necessary to set the threshold value N small. In the example shown in FIG. 7B, the threshold value at which the cumulative number of vehicles (estimated number of vehicles on the vertical axis in FIG. 7B) and the actual number of vehicles are closest is 11, and in the example shown in FIG. 7C, the threshold value at which the cumulative number of vehicles (estimated number of vehicles on the vertical axis in FIG. 7C) and the actual number of vehicles are closest is 2. If the threshold value N is set large, the estimated number of vehicles will be smaller than the actual number of vehicles. That is, the optimum threshold value N for estimating the accurate number of passing vehicles tends to be larger for a healthier structure 50 and tends to be smaller for more deteriorated structure 50. Therefore, by evaluating the optimum threshold value N, the deterioration state of the structure 50 can be easily evaluated.

[0072] Specifically, the evaluation unit 422 first generates a histogram of the cumulative vehicle count using the generated simultaneous hit histogram as described above. Next, the evaluation unit 422 determines the estimated vehicle count having a value closest to the reference value using the generated histogram of the cumulative vehicle count. Then, the evaluation unit 422 determines a threshold value N at which the determined estimated vehicle count is obtained. If the determined threshold value N is equal to or greater than a predetermined value, the evaluation unit 422 evaluates that the structure is healthy. On the other hand, if the determined threshold value N is less than a predetermined value, the evaluation unit 422 evaluates that the structure is deteriorated. Note that, at this time, the evaluation unit 422 may evaluate that the deterioration is more advanced as the determined threshold value N is lower (as the threshold value N falls below a predetermined value). That is, the evaluation unit 422 may evaluate the deterioration state in stages according to the value of the determined threshold value N.

[0073] In this way, the threshold N of the number of simultaneously hit sensors can be used as a simple index of the deterioration state of the structure 50. The reference value can be an actual measurement value of passing vehicles measured by other sensing methods that are not affected by the internal damage state of the structure, such as a magnetic sensor or a distortion sensor, an actual measurement value of passing vehicles measured based on Weigh-In-Motion (WIM), an average traffic volume under normal circumstances, or an actual measurement value (traffic counter) or a statistical value obtained by a road administrator or the like.

[0074] According to the structure evaluation system 100 in the second embodiment configured as described above, the reference value and the estimated number of vehicles are compared to determine the estimated number of vehicles closest to the reference value, and the threshold N of the number of simultaneous hit sensors at which the determined estimated number of vehicles is obtained is determined. Then, the evaluation unit 422 evaluates the deterioration state of the structure 50 according to the determined threshold N of the number of simultaneous hit sensors. This makes it possible to evaluate the deterioration state of the structure 50 in a simple manner without performing position location of the elastic wave source. Furthermore, as described above, it is considered that the lower the threshold N of the number of simultaneous hit sensors, the more advanced the deterioration is. Therefore, the evaluation unit 422 can evaluate the degree of deterioration in stages according to the determined threshold N of the number of simultaneous hit sensors.

[0075] (Third embodiment) In the third embodiment, a configuration is described in which the number of vehicles estimated by the vehicle number estimation unit is compared with a reference value, and the deterioration state of a structure is evaluated according to the degree of deviation. The system configuration and the configuration of each device in the third embodiment are the same as those in the first embodiment. The following description focuses on the differences from the first embodiment.

[0076] The more the structure 50 deteriorates, the lower the number of simultaneous hit sensors. Therefore, the number of vehicles simultaneously detected by a large number of sensors 20 decreases as the structure 50 deteriorates. As a result, the more the structure 50 deteriorates, the larger the value of the threshold N of the simultaneous hit sensor number is, the larger the deviation between the actual number of vehicles and the estimated number of vehicles estimated by the vehicle number estimation unit 309 becomes. Under such assumptions, when the threshold N of the simultaneous hit sensor number is fixed to a large value such as "15" for the total number of sensors 20 of "18" and the number of vehicles is estimated, the deterioration state of the structure 50 can be simply evaluated by comparing the estimated number of vehicles with the actual number of vehicles. Specifically, the evaluation unit 422 evaluates that the structure 50 is more deteriorated as the estimated number of vehicles is smaller than the actual number of vehicles. In other words, the evaluation unit 422 evaluates that the structure 50 is more deteriorated as the deviation between the actual number of vehicles and the estimated number of vehicles is larger. That is, the evaluation unit 422 may evaluate the deterioration state in stages according to the degree of deviation. Note that, when the difference between the actual number of vehicles and the estimated number of vehicles is smaller than a certain threshold, the evaluation unit 422 may evaluate that the deterioration of the structure 50 is not progressing or that the structure 50 is sound.

[0077] Here, the measured vehicle number is acquired as a reference value by the method shown in the second embodiment. The threshold N of the number of simultaneous hit sensors is appropriately set by the user. As described above, it is expected that the larger the value of the threshold N of the number of simultaneous hit sensors is, the larger the discrepancy between the measured vehicle number and the estimated number of vehicles estimated by the vehicle number estimation unit 309 will be. Therefore, it is better to have a larger value of the threshold N of the number of simultaneous hit sensors.

[0078] According to the structure evaluation system 100 in the third embodiment configured as described above, the deterioration state of the structure 50 is evaluated simply according to the degree of discrepancy between the measured number of vehicles and the estimated number of vehicles. This makes it possible to evaluate the deterioration state of the structure 50 in a simple manner without locating the position of the elastic wave source. Furthermore, as described above, it is considered that the greater the degree of discrepancy between the measured number of vehicles and the estimated number of vehicles, the more advanced the deterioration is. Therefore, the evaluation unit 422 can evaluate the degree of deterioration in stages according to the degree of discrepancy between the measured number of vehicles and the estimated number of vehicles.

[0079] (Modification 1 common to each embodiment) In each of the above embodiments, a configuration has been shown in which a plurality of sensors 20-1 to 20-n are connected to one signal processing unit 30. The structure evaluation system 100 may include a plurality of signal processing units 30, and each sensor 20 may be connected to a different signal processing unit 30.

[0080] (Modification 2 common to each embodiment) Some or all of the functional units included in the structure evaluation device 40 may be included in another device. For example, the display unit 44 included in the structure evaluation device 40 may be included in the other device. When configured in this manner, the structure evaluation device 40 transmits the evaluation results to the other device equipped with the display unit 44. The other device equipped with the display unit 44 displays the received evaluation results.

[0081] (Modification 3 common to each embodiment) In any of the above-mentioned methods, it is necessary to consider the vehicle travel position relative to the sensor position in order to improve the evaluation accuracy. For example, when the vehicle passage position and the measurement range of the sensor 20 are separated by a certain distance or more in the direction perpendicular to the vehicle travel axis, the evaluation unit 422 shifts the histogram of the number of simultaneous hit sensors or the graph of the estimated number of vehicles against the threshold N of the number of simultaneous hit sensors to a smaller number of simultaneous hit sensors overall according to the distance. As a result, the evaluation unit 422 changes the evaluation criterion based on the relative positional relationship between the sensor installation position and the vehicle passing position. Therefore, the greater the distance between the positional relationship between the vehicle passage position and the sensor installation position, the more correction is required to shift the soundness evaluation criterion toward the deterioration side.

[0082] (Modification 4 common to each embodiment) When the deterioration of the structure 50 to be evaluated is progressing and the number of simultaneous hit sensors tends to be small, it is possible that the undetected vehicles are concentrated in the sensors 20 arranged at a specific position. In this case, there is a high possibility that localized damage exists between the vehicle passing position and the installation position of the sensor 20 where the undetected vehicles are unevenly distributed. Therefore, when the sensors 20 that have not detected the vehicles are concentrated in a specific sensor 20, the evaluation unit 422 can estimate the damaged position inside the structure 50. For example, when the group of sensors is arranged one-dimensionally along the average vehicle passing position so as to be at a certain distance from the passing position, the evaluation unit 422 can identify the damaged position along the passing position based on the change or difference in the vehicle detection state of each sensor. In this way, when there is a sensor 20 that detects a relatively small number of passing vehicles among the multiple installed sensors 20, the evaluation unit 422 may determine that the area around the installation position of the sensor with the relatively small number of passing vehicles is an area where deterioration is occurring. Here, the sensor 20 with a relatively small number of passing vehicles is a sensor with a number of vehicles detected by other sensors 20 that is less than a threshold value or more.

[0083] According to at least one of the embodiments described above, the structure evaluation system 100 of the embodiment has a plurality of sensors 20, a vehicle number estimation unit 309, and an evaluation unit 422. The plurality of sensors 20 detect elastic waves generated inside the structure 50. The vehicle number estimation unit 309 estimates the number of vehicles that have passed through the structure 50 based on the plurality of elastic waves detected by each of the plurality of sensors 20. The evaluation unit 422 evaluates the deterioration state of the structure 50 using vehicle information related to the number of vehicles estimated by the vehicle number estimation unit 309, thereby making it possible to evaluate the deterioration state of the structure without locating the position of the elastic wave source.

[0084] A part of the processing performed by the signal processing unit 30 in the above-mentioned embodiment (for example, the processing performed by the vehicle number estimation unit 309) may be realized by a computer. In that case, a program for realizing this function may be recorded in a computer-readable recording medium, and the program recorded in the recording medium may be read into a computer system and executed to realize the function. Note that the term "computer system" here includes hardware such as an OS and peripheral devices. Furthermore, the term "computer-readable recording medium" refers to portable media such as flexible disks, optical magnetic disks, ROMs, and CD-ROMs, and storage devices such as hard disks built into a computer system. Furthermore, the term "computer-readable recording medium" may include a device that dynamically holds a program for a short period of time, such as a communication line when a program is transmitted via a network such as the Internet or a communication line such as a telephone line, and a device that holds a program for a certain period of time, such as a volatile memory inside a computer system that is a server or client in that case. Furthermore, the above-mentioned program may be a program for realizing a part of the above-mentioned function, or may be a program that can realize the above-mentioned function in combination with a program already recorded in the computer system, or may be a program that is realized using a programmable logic device such as an FPGA.

[0085] Although some embodiments of the present invention have been described, these embodiments are presented as examples and are not intended to limit the scope of the invention. These embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention. These embodiments and their modifications are included in the scope of the invention and its equivalents described in the claims, as well as in the scope and spirit of the invention. [Explanation of symbols]

[0086] 20-1 to 20-n... sensors, 30... signal processing unit, 40... structure evaluation device, 41... communication unit, 42... control unit, 43... storage unit, 44... display unit, 301... amplifier, 302... A / D converter, 303... waveform shaping filter, 304... gate generation circuit, 305... arrival time determination unit, 306... feature extraction unit, 307... data recording unit, 308... memory, 309... vehicle number estimation unit, 421... acquisition unit, 422... evaluation unit

Claims

1. A plurality of sensors for detecting elastic waves generated inside the structure; a vehicle number estimation unit that estimates the number of vehicles that have passed through the structure based on a plurality of elastic waves detected by each of the plurality of sensors; an evaluation unit that evaluates a deterioration state of the structure using vehicle information regarding the number of vehicles estimated by the vehicle number estimation unit; and A structure evaluation system comprising:

2. The vehicle number estimation unit calculates the number of sensors that detect the same vehicle as the number of simultaneous hit sensors, the evaluation unit evaluates the deterioration state of the structure based on a distribution shape or a peak position of a histogram of the estimated number of vehicles with respect to the number of simultaneous hit sensors. The structure evaluation system according to claim 1 .

3. the evaluation unit evaluates the structure to be sound when the distribution shape of the histogram is such that the estimated number of vehicles is greatest at a position where the number of simultaneously hit sensors is close to the total number of the plurality of sensors, or when the peak position of the histogram is a position where the number of simultaneously hit sensors is close to the total number of the plurality of sensors, and evaluates the structure to be deteriorated in other cases. The structure evaluation system according to claim 2 .

4. The vehicle number estimation unit calculates the number of sensors that detect the same vehicle as the number of simultaneous hit sensors, calculating a final estimated number of passing vehicles as an accumulation result of the estimated number of vehicles whose calculated simultaneous hit sensor count is equal to or greater than a threshold value; the evaluation unit compares the estimation result with a reference value and evaluates the deterioration state of the structure based on the closest threshold value. The structure evaluation system according to claim 1 .

5. The evaluation unit compares the number of vehicles estimated by the vehicle number estimation unit with a reference value, and evaluates a deterioration state of the structure according to a degree of deviation. The structure evaluation system according to claim 1 .

6. The reference value is any one of an estimated number of vehicles measured using a magnetic sensor, a statistical average traffic volume under normal circumstances, a value obtained by a traffic counter, and an actual measurement value of the number of passing vehicles. The structure evaluation system according to claim 5 .

7. The evaluation unit changes the evaluation criterion based on a relative positional relationship between a sensor installation position and a vehicle passing position. The structure evaluation system according to any one of claims 1 to 6.

8. When a sensor that detects a relatively small number of passing vehicles is present among the multiple installed sensors, the evaluation unit determines that an area around an installation position of the sensor that detects a relatively small number of passing vehicles is an area where deterioration is occurring. The structure evaluation system according to any one of claims 1 to 6.

9. estimating the number of vehicles that have passed through the structure based on a plurality of elastic waves detected by a plurality of sensors that detect elastic waves generated inside the structure; evaluating a deterioration state of the structure using vehicle information related to the estimated number of vehicles; Structural evaluation methods.

10. a vehicle number estimation unit that estimates the number of vehicles that have passed through the structure based on a plurality of elastic waves detected by a plurality of sensors that detect elastic waves generated inside the structure; an evaluation unit that evaluates a deterioration state of the structure using vehicle information related to the estimated number of vehicles; A structure evaluation device comprising:

Images