Bridge pier soundness evaluation system and bridge pier soundness evaluation device

Abstract

To provide a bridge pier soundness evaluation system and a bridge pier soundness evaluation device allowing an operator to intuitively evaluate the soundness of a bridge pier.SOLUTION: The pier soundness evaluation system 1 includes a server 20 and a display terminal 30 that communicates with the server 20, the server 20 includes a communication unit 23 that receives continuous micro-vibration data transmitted from an acceleration sensor 10 provided on a pier, a spectrum analysis unit 211 that performs spectrum analysis on the continuous micro-vibration data received by the communication unit 23 to generate a spectrum waveform in which a peak appears in a natural frequency of the pier, and a soundness evaluation data generation unit 212 that generates soundness evaluation data obtained by comparing the natural frequency of the pier measured by an impact vibration test of applying a blow to the pier with the spectrum waveform. A communication unit 23 that transmits the soundness evaluation data generated by the soundness evaluation data generation unit 212, and the display terminal 30 displays the soundness evaluation data transmitted from the communication unit 23.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a bridge pier soundness evaluation system and a bridge pier soundness evaluation device. [Background technology]

[0002] In recent years, heavy rain disasters such as torrential rains and typhoons have become more frequent. Due to the risk of riverbed subsidence and localized scouring at river bridge piers (also called "river piers") caused by the strong currents flowing through rivers, there is a growing demand for bridge pier soundness assessment. Impact vibration testing has been widely used as a method for assessing the soundness of substructures such as railway bridge piers (see, for example, Patent Document 1). This method involves striking a pier with a 30 kg weight, determining its natural frequency from the response, and evaluating the soundness of the pier from the natural frequency. The natural frequency obtained from an impact vibration test conducted before riverbed subsidence or localized scouring around the pier occurs is saved as reference data. The soundness of the pier can then be assessed by comparing the natural frequency of the pier obtained by conducting another impact vibration test with the saved reference data. However, soundness assessment using the natural frequency obtained by impact vibration testing has problems such as the difficulty of frequently conducting impact vibration tests and the danger of approaching the pier to conduct the test when the water level is high. Therefore, attempts have been made to install acceleration sensors on the piers and determine the natural frequency of the piers from the measurements of the acceleration sensors (see, for example, Patent Document 2). Patent Document 2 discloses technology for steadily and safely monitoring changes in the bearing capacity of piers due to scouring and other factors. Specifically, an acceleration sensor installed on the pier detects the acceleration of the pier during microtremors, and a fast Fourier transform is performed to obtain a Fourier spectrum of the acceleration information.The Fourier spectrum is then averaged over time and frequency, and the averaged Fourier spectrum is weighted by the weighted spectrum of the pier when it is in good condition (the weighted spectrum is set in advance based on the transfer function of the pier when it is in good condition).The area of ​​the weighted spectrum is then calculated and normalized by the area of ​​the weighted spectrum when it is in good condition.The normalized area is then compared and evaluated with a preset threshold value, thereby quantitatively monitoring and evaluating the bearing capacity of the pier based on the microtremors. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2021-139237 [Patent Document 2] Japanese Patent Application Laid-Open No. 2000-186984 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the conventional technology described in Patent Document 2, the normalized area of ​​the Fourier spectrum of acceleration information is compared with a preset threshold value to evaluate the soundness of the pier, so the operator can only obtain information on whether the soundness of the pier exceeds the threshold value, making it difficult for the operator to intuitively evaluate the soundness of the pier from the current state of the natural frequency.

[0005] The present invention has been made based on the above-mentioned awareness of the problem, and aims to provide a pier soundness evaluation system and a pier soundness evaluation device that allow an operator to intuitively evaluate the soundness of a pier. [Means for solving the problem]

[0006] The pier soundness evaluation system of this embodiment is a pier soundness evaluation system comprising a server and a display terminal that communicates with the server, wherein the server comprises: a receiving unit that receives microtremor data transmitted from an acceleration sensor installed on the pier; an analysis unit that performs spectral analysis of the microtremor data received by the receiving unit to generate a spectral waveform in which a peak appears at the natural frequency of the pier; a soundness evaluation data generation unit that generates soundness evaluation data that compares the natural frequency of the pier measured by an impact vibration test in which an impact is applied to the pier with the spectral waveform; and a transmission unit that transmits the soundness evaluation data generated by the soundness evaluation data generation unit, and the display terminal displays the soundness evaluation data transmitted from the transmission unit.

[0007] Furthermore, the pier soundness evaluation device of this embodiment is characterized by comprising a receiving unit that receives microtremor data transmitted from an acceleration sensor installed on the pier, an analysis unit that performs spectral analysis of the microtremor data received by the receiving unit to generate a spectral waveform in which a peak appears at the natural frequency of the pier, and a soundness evaluation data generation unit that generates soundness evaluation data that compares the spectral waveform with the natural frequency of the pier measured by an impact vibration test in which an impact is applied to the pier. [Effects of the Invention]

[0008] According to the present invention, soundness evaluation data that compares the natural frequency of the pier measured by impact vibration testing with the spectral waveform in which a peak appears at the natural frequency of the pier obtained from constant microtremor data is displayed on a display terminal, so that the operator can intuitively evaluate the soundness of the pier simply by visually checking the soundness evaluation data. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a conceptual diagram showing an example of the technical concept of a pier soundness evaluation system and a pier soundness evaluation device according to an embodiment of the present invention. [Figure 2] FIG. 2 is a diagram showing an example of functional blocks of a pier soundness evaluation system. [Figure 3] FIG. 10 is a diagram showing a spectral waveform including the natural frequency of an arbitrary bridge pier measured by an impact vibration test. [Figure 4] FIG. 10 is a diagram showing an example of time-series changes in microtremor data stored in a microtremor data storage unit. [Figure 5] FIG. 10 is a diagram illustrating an example of an event. [Figure 6] FIG. 10 is a diagram showing an example of a first spectral waveform generated from microtremor data corresponding to a first evaluation interval. [Figure 7] 10 is a diagram showing an example of a display based on soundness evaluation data generated by a soundness evaluation data generating unit. FIG. [Figure 8]FIG. 10 is a diagram showing an example of time-series changes in the natural frequency, which is the peak of the spectrum waveform displayed on the display unit of the display terminal. [Figure 9] FIG. 10 is a diagram showing another example of time-series changes in microtremor data stored in the microtremor data storage unit. [Figure 10] 10 is a diagram showing an example of a display based on soundness evaluation data generated by a soundness evaluation data generating unit. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0010] FIG. 1 is a conceptual diagram showing an example of the technical concept of the pier soundness evaluation system and pier soundness evaluation device according to this embodiment.

[0011] The pier soundness evaluation system 1 is a system that evaluates the soundness of a pier 51 based on soundness evaluation data. The pier soundness evaluation system 1 includes n acceleration sensors 10-1, 10-2 to 10-n (n is a natural number equal to or greater than 1), a server (pier soundness evaluation device) 20, and a display terminal 30. The pier soundness evaluation system 1 may include components other than those shown in FIG. 1. When the n acceleration sensors 10-1, 10-2 to 10-n are not particularly distinguished from one another, they will be simply referred to as "acceleration sensors 10."

[0012] The acceleration sensor 10 is provided on a pier 51 that constitutes a bridge 50, and outputs continuous microtremor data. The acceleration sensor 10 outputs the acceleration detected at the pier 51 as continuous microtremor data. The bridge 50 is a structure that allows railways, vehicles, and people to cross rivers or roads, and the pier 51 is a part of the bridge 50, constituting a column or leg that is installed on a riverbed or other land to support the bridge 50. In this embodiment, the acceleration sensor 10 is particularly applied to the pier 51 of the bridge 50 that is installed so that railways can cross rivers, but is not limited to this. The acceleration sensor 10 may also be applied to bridge girders among the structures that constitute the bridge 50, or for other purposes.

[0013] The acceleration sensor 10 constantly detects micro-vibrations generated from the pier 51 and outputs them as micro-tremor data. Micro-tremor data refers to acceleration data detected by the acceleration sensor 10 of minute vibrations constantly generated by the pier 51. The micro-tremor data detected by the acceleration sensor 10 includes not only micro-tremor data constantly generated from the pier 51, but also vibrations caused by the bridge girders and accessories to the bridge girders (such as utility poles). In this embodiment, the acceleration sensor 10 is mounted on the top surface of the pier 51, but this is not limitative and the acceleration sensor 10 may be mounted at any location on the pier 51 or on the bridge girders.

[0014] The acceleration sensor 10 is communicatively connected to the server 20 via a communication line, such as wireless or wired communication. Wireless communication can be achieved using a mobile communication line, wireless LAN, Bluetooth (registered trademark), or the like. Wired communication can be achieved using Ethernet (registered trademark), optical fiber, coaxial cable, or USB (Universal Serial Bus). The acceleration sensor 10 transmits the continuous tremor data detected from the bridge pier 51 to the server 20 as an electrical signal. Transmission from the acceleration sensor 10 to the server 20 uses LTE-M via the network N as a mobile communication line. LTE-M is a cellular LPWA (Low Power Wide Area) standard designed for power saving. Therefore, using LTE-M as the communication line can reduce the power consumption of the acceleration sensor 10 and the frequency of battery replacement, thereby reducing maintenance costs. The communication line is not limited to LTE-M. Mobile communication lines such as 4th generation mobile communication systems (4G) and 5th generation mobile communication systems (5G), such as LTE (Long Term Evolution) lines, may also be used.

[0015] The acceleration sensor 10 can be a battery-powered accelerometer equipped with a low-power wireless device made using MEMS (Micro-Electro-Mechanical Systems) technology, known as a MEMS accelerometer. The microtremor data is transmitted from the acceleration sensor 10 to the server 20 in multiple batches, each containing several tens of minutes of data per day. The frequency with which the microtremor data is transmitted from the acceleration sensor 10 to the server 20 can be changed as desired.

[0016] For example, during normal times when it is not raining and there is little chance of a river flooding event occurring, the server 20 transmits an instruction signal to the acceleration sensor 10 to decrease the transmission frequency. The transmission of the instruction signal may be executed based on an instruction input by an operator to the server 20 or the display terminal 30, or may be executed based on whether the amount of precipitation, probability of precipitation, etc. in the weather forecast data periodically received via the network N is above a predetermined threshold. Upon receiving the instruction signal to decrease the transmission frequency, the acceleration sensor 10 decreases the frequency of transmitting microtremor data from the acceleration sensor 10 to the server 20 based on the instruction signal transmitted from the server 20. This reduces the power consumption of the acceleration sensor 10, and by reducing the frequency of battery replacement, maintenance costs can be reduced.

[0017] On the other hand, in an abnormal situation where heavy rain is likely to cause a river flood, the server 20 transmits an instruction signal to the acceleration sensor 10 to increase the transmission frequency. The instruction signal may be transmitted based on an instruction input by an operator to the server 20 or the display terminal 30, or based on whether the precipitation amount, precipitation probability, etc. in the weather forecast data periodically received via the network N are above a predetermined threshold. Upon receiving the instruction signal to increase the transmission frequency, the acceleration sensor 10 increases the frequency of transmitting microtremor data to the server 20 based on the instruction signal transmitted from the server 20. This allows the server 20 to quickly evaluate the soundness of the bridge pier 51. In this way, the monitoring frequency of the acceleration sensor 10 can be arbitrarily changed based on instructions from the server 20, allowing the soundness of the bridge pier 51 to be evaluated at an appropriate timing depending on the situation.

[0018] As shown in FIG. 1, the bridge pier soundness evaluation system 1 may further include a gateway 11. When the bridge pier soundness evaluation system 1 includes the gateway 11, the acceleration sensor 10 may transmit microtremor data to the server 20 through the gateway 11. In this case, communication between the acceleration sensor 10 and the gateway 11 is performed using LPWA. The microtremor data transmitted from the acceleration sensor 10 to the gateway 11 is then transmitted to the server 20 via a mobile communication line such as LTE-M, 4G, or 5G. This reduces the power consumption of the acceleration sensor 10 and reduces the frequency of battery replacement, thereby reducing maintenance costs. Meanwhile, because the acceleration sensor 10 is connected to the server 20 through the gateway 11, the microtremor data output by the acceleration sensor 10 can be rapidly transmitted to the server 20 via a high-speed mobile communication line, allowing the server 20 to immediately generate soundness evaluation data.

[0019] FIG. 2 is a diagram showing an example of functional blocks of the pier soundness evaluation system 1. As shown in FIG.

[0020] The server 20 includes a control unit 21, a storage unit 22, and a communication unit (a receiving unit and a transmitting unit) 23. The server 20 is configured by an information processing device such as a PC (Personal Computer).

[0021] The control unit 21 comprehensively controls the entire server 20 and has a CPU (Central Processing Unit) that reads programs and executes control processes. The control unit 21 controls the operation of the entire server 20 by expanding programs stored in a RAM (Random Access Memory), ROM (Read Only Memory), HDD (Hard Disk Drive), SSD (Solid State Drive), etc. of the storage unit 22 into the RAM of the storage unit 22 and sequentially executing the programs. The control unit 21 controls the operation of the entire server 20 by executing various programs such as OS programs and application programs.

[0022] The control unit 21 includes a spectrum analysis unit (analysis unit) 211, a soundness evaluation data generation unit 212, and an evaluation section extraction unit 213. The storage unit 22 includes an impact vibration test data storage unit 221 and a microtremor data storage unit 222.

[0023] The memory unit 22 is a RAM, ROM, HDD, SSD, etc., and stores the program executed by the control unit 21, the constant microtremor data transmitted from the acceleration sensor 10, information on the natural frequency of the pier 51 measured by impact vibration testing, etc.

[0024] The communication unit 23 communicates with other terminals via a network N such as the Internet under the control of the control unit 21. The communication with other terminals is performed by wired communication or wireless communication. For example, the communication unit 23 communicates with the acceleration sensor 10 and the display terminal 30 via the network N under the control of the control unit 21. The communication unit 23 is, for example, a network adapter.

[0025] The communication unit 23 receives the microtremor data transmitted from the acceleration sensor 10. The microtremor data storage unit 222 stores the microtremor data received by the communication unit 23. The microtremor data storage unit 222 can associate the microtremor data received by the communication unit 23 with each acceleration sensor 10-1, 10-2 to 10-n and store the microtremor data separately for each pier 51. This makes it possible to uniquely identify which of the multiple piers 51 the microtremor data belongs to. The microtremor data storage unit 222 may store the microtremor data in chronological order, or may store it in association with time.

[0026] The display terminal 30 includes a control unit 31, a storage unit 32, an input unit 33, a display unit 34, and a communication unit 35. The display terminal 30 is configured by a mobile terminal device such as a smartphone, a tablet terminal, or a notebook PC.

[0027] The control unit 31 comprehensively controls the entire display terminal 30, and has a CPU that reads programs and executes control processing. The control unit 31 controls the operation of the entire display terminal 30 by expanding programs stored in the RAM, ROM, HDD, SSD, etc. of the storage unit 32 into the RAM of the storage unit 32 and sequentially executing the programs. The control unit 31 controls the operation of the entire display terminal 30 by executing various programs such as OS programs and application programs.

[0028] The storage unit 32 is a RAM, a ROM, an HDD, an SSD, or the like, and stores the program executed by the control unit 31, the health evaluation data D transmitted from the server 20, and the like.

[0029] The display unit 34 is, for example, a liquid crystal display (LCD) or an organic electroluminescence (EL) display, and displays an operation screen or the like to an operator who operates the display terminal 30 under the control of the control unit 31. The display unit 34 also displays a selection screen for accepting the selection of an evaluation section, which will be described later. The display unit 34 also displays soundness evaluation data, which will be described later, transmitted from the server 20.

[0030] The input unit 33 accepts data input based on operation by the operator of the display terminal 30. The input unit 33 is composed of a keyboard, a mouse, a touch panel, etc. The input unit 33 accepts the selection of an arbitrary evaluation section arbitrarily specified by the operator. Information on the arbitrary evaluation section specified by the operator is transmitted to the server 20 via the communication unit 35. The arbitrary evaluation section also includes information on the first evaluation section, second evaluation section, etc., which will be described later. This allows the operator to specify an arbitrary evaluation section by operating the input unit 33.

[0031] The communication unit 35 communicates with other terminals via a network N such as the Internet under the control of the control unit 31. The communication with other terminals is performed by wired communication or wireless communication. For example, the communication unit 35 communicates with the server 20 via the network N under the control of the control unit 31. The communication unit 35 is, for example, a network adapter.

[0032] The communication unit 35 receives the health evaluation data transmitted from the server 20. The storage unit 32 may store the health evaluation data received by the communication unit 35. In addition, the communication unit 35 transmits to the server 20 any evaluation section arbitrarily designated by the operator of the display terminal 30.

[0033] Before evaluating the soundness using the pier soundness evaluation system 1, it is necessary to obtain the natural frequency of the pier 51 measured by conducting an impact vibration test (hereinafter simply referred to as "impact vibration test") in which an impact is applied to the pier 51 to be evaluated. The natural frequency of the pier 51 measured by the impact vibration test becomes a standard index for evaluating the soundness of the pier 51.

[0034] In the impact vibration test, for example, a 30 to 100 kg weight is applied to the pier 51, and the vibration in response to the impact is acquired, thereby measuring the natural frequency. The impact vibration test can be performed using an existing test. The spectral waveform S0 (or natural frequency) in which the natural frequency of the pier 51 measured by the impact vibration test appears is stored in the impact vibration test data storage unit 221 of the server 20. If the impact vibration test is performed on multiple piers 51, there will be multiple spectral waveforms S0 (or natural frequencies) of the piers 51 measured by the impact vibration test. In this case, the impact vibration test data storage unit 221 stores spectral waveforms S0 (or natural frequencies) associated with each of the multiple piers 51. This allows the server 20 to uniquely identify the natural frequency measured at each pier 51 for each pier 51.

[0035] FIG. 3 is a diagram showing a spectral waveform S0 including the natural frequency of an arbitrary pier 51 measured by an impact vibration test. FIG. 3 is a graph showing the amplitude of the impact vibration test (hereinafter also referred to as "impact vibration test amplitude") on the vertical axis and the frequency on the horizontal axis. The frequency may also be shown as a frequency. The spectral waveform S0 shown in FIG. 3 is an example of a test result performed to explain the present invention. In the example shown in FIG. 3, the spectral waveform S0 of the arbitrary pier 51 measured by the impact vibration test has a peak at a frequency of "10.74 Hz." Therefore, the natural frequency of the arbitrary pier 51 measured by the impact vibration test is "10.74 Hz." The impact vibration test data storage unit 221 stores the spectral waveform S0 including the natural frequency "10.74 Hz" of the arbitrary pier 51 measured by the impact vibration test in the impact vibration test data storage unit 221 as a reference index for evaluating the soundness of the pier 51.

[0036] The spectrum analysis unit 211 performs spectrum analysis on the microtremor data received by the communication unit 23 to generate a spectrum waveform in which a peak appears at the natural frequency of the pier 51. For example, the spectrum analysis unit 211 performs spectrum analysis on the microtremor data stored in the microtremor data storage unit 222 by using a Fourier transform or the like. The spectrum analysis unit 211 may perform spectrum analysis on the microtremor data received by the communication unit 23 after performing numerical processing using parameters determined for each pier 51. The spectrum waveform generated by the spectrum analysis unit 211 is generated based on the microtremor data transmitted from the acceleration sensor 10 provided on any pier 51, and therefore represents the soundness of the any pier 51.

[0037] 4 is a diagram showing an example of time-series changes in the microtremor data C stored in the microtremor data storage unit 222. The microtremor data C is represented by a graph in which the vertical axis indicates the acceleration of the acceleration sensor 10 and the horizontal axis indicates time.

[0038] The evaluation section extraction unit 213 extracts microtremor data of any evaluation section from the microtremor data C stored in the microtremor data storage unit 222. An evaluation section refers to a period during which the soundness of the pier 51 is evaluated within a predetermined time stored in the microtremor data storage unit 222. The evaluation section extraction unit 213 extracts microtremor data of at least one evaluation section from the microtremor data C.

[0039] In this embodiment, the evaluation interval extraction unit 213 extracts microtremor data C1 corresponding to a first evaluation interval F1 from the microtremor data C. The first evaluation interval F1 illustrated in FIG. 4 is an interval indicated by the interval from time t1 to time t2. The microtremor data C1 is an acceleration measurement value output from the acceleration sensor 10 between time t1 and time t2. The first evaluation interval F1 is an example of a specific evaluation interval arbitrarily designated by the operator.

[0040] Among the arbitrary evaluation sections, any section arbitrarily designated by the operator of the display terminal 30 becomes the first evaluation section F1. For example, if the operator wants to see how the natural frequency of the pier has changed before and after an event, the first evaluation section F1 is designated as either the section before or after the event occurrence section related to the pier 51, or either of these sections.

[0041] An event occurrence section refers to a section where an event occurs or where an event has occurred, which may have a significant impact on the soundness of the bridge pier 51, including natural disasters such as heavy rain, river flooding, drought, earthquake, landslide, tsunami, land subsidence, fire, lightning strike, typhoon, etc. The soundness of the bridge pier 51 is an index for evaluating the condition and performance of the bridge pier 51 and determining whether it is maintaining appropriate function.

[0042] FIG. 5 is a diagram showing an example of an event. FIG. 5(1) explains an example of an event in which the water level of a river changes. In FIG. 5(1), the water level 60 in the river increases due to heavy rain or the like, causing the river to change from water level 61A to water level 61B. When the water level increases from 61A to 61B, the flow of water 60 hitting the pier 51 increases, which may increase the burden on the pier 51. In this way, even if the occurrence of an event causes the water level 60 in the river to increase (flood) from water level 61A to water level 61B, there will be no significant change in the natural frequency of the pier 51 if there is no change in the condition (soundness) of the base of the pier 51.

[0043] Figure 5(2) illustrates an example of an event in which the riverbed changes. In Figure 5(2), soil 62 supporting the bridge pier 51 is scoured (eroded) by water flow due to rising water levels, etc., causing the riverbed to change from height 63A to height 63B. When the riverbed drops from height 63A to height 63B, the soil 62 supporting the pier 51 decreases, which may cause the stability of the pier 51 to be compromised. As a result, the soundness of the pier 51 may be reduced.

[0044] In this embodiment, to allow the operator to easily grasp the soundness of the pier 51, which changes due to the occurrence of the above-mentioned events and the passage of time, the natural frequency (reference value) obtained by the impact vibration test is displayed in comparison with a spectral waveform in which a peak appears at the natural frequency obtained from the microtremor data (FIG. 7). For this purpose, soundness evaluation data is generated by comparing the natural frequency of the pier 51 measured by the impact vibration test with a spectral waveform generated by spectrally analyzing the microtremor data transmitted from the acceleration sensor 10. The generated soundness evaluation data is displayed on the screen of a display terminal monitored by the operator. By having the operator visually confirm the soundness evaluation data that compares the natural frequency (reference value) obtained by the impact vibration test with the spectral waveform in which a peak appears at the natural frequency obtained from the microtremor data, the operator can intuitively evaluate the soundness of the pier 51. The soundness evaluation data will be described later.

[0045] The spectrum analysis unit 211 performs a spectrum analysis on the extracted microtremor data for any evaluation interval to generate a spectrum waveform in which a peak appears at the natural frequency. There are no particular limitations on the method for generating a spectrum waveform in which a peak appears at the natural frequency. For example, the spectrum analysis unit 211 may perform a spectrum analysis on the microtremor data for the evaluation interval using a fast Fourier transform (FFT) or the like to generate a spectrum waveform.

[0046] The display terminal 30 receives input of information about, for example, the first evaluation section F1 through an operator's operation, and transmits the received information about the first evaluation section F1 to the server 20. The spectrum analysis unit 211 extracts microtremor data C1 corresponding to the first evaluation section F1 based on the information about the first evaluation section F1 transmitted from the display terminal 30. The spectrum analysis unit 211 performs spectral analysis of the extracted microtremor data for the first evaluation section F1 using a fast Fourier transform (FFT) or the like to generate a first spectral waveform. The spectrum analysis unit 211 transmits the generated first spectral waveform to the soundness evaluation data generation unit 212.

[0047] FIG. 6 is a diagram showing an example of a first spectral waveform S1 generated from microtremor data corresponding to the first evaluation section F1. FIG. 6 is a graph showing the amplitude of the spectral waveform (hereinafter also referred to as "spectral waveform amplitude") on the vertical axis and the frequency on the horizontal axis. The frequency may be represented by frequency. The first spectral waveform S1 shown in FIG. 6 is an example of the results of a test conducted to explain the present invention. As shown in FIG. 6, the first spectral waveform S1 corresponding to an arbitrary pier 51 generated by the spectrum analysis unit 211 is a waveform in which a peak appears at the natural frequency of "10.82 Hz." The spectrum analysis unit 211 sends the first spectral waveform S1, which has been generated based on the microtremor data and in which a peak appears at the natural frequency of "10.82 Hz" of the arbitrary pier 51, to the soundness evaluation data generation unit 212 as comparison data for evaluating the soundness of the arbitrary pier 51.

[0048] The soundness evaluation data generation unit 212 generates soundness evaluation data D by comparing a spectral waveform S0 (or the natural frequency of the pier 51) including the natural frequency of any pier 51 measured by the impact vibration test with a first spectral waveform S1 generated by the spectrum analysis unit 211. The soundness evaluation data generation unit 212 generates information by comparing, on one screen, the spectral waveform S0 in which the natural frequency of the pier 51 measured by the impact vibration test appears with the first spectral waveform S1 generated by the spectrum analysis unit 211, as soundness evaluation data D (see FIG. 7 ). The spectral waveform S0 (or the natural frequency of the pier 51) of the pier 51 measured by the impact vibration test is stored in the impact vibration test data storage unit 221. Therefore, the soundness evaluation data generation unit 212 refers to the impact vibration test data storage unit 221 to extract the spectral waveform S0 (or the natural frequency of the pier 51) of the pier 51 to be subjected to soundness evaluation. Then, the soundness evaluation data generation unit 212 generates soundness evaluation data D that displays a comparison between the spectral waveform S0 including the extracted natural frequency of the pier 51 and the first spectral waveform S1 generated by the spectral analysis unit 211. The generated soundness evaluation data D is transmitted to the display terminal 30 via the communication unit 23.

[0049] Fig. 7 is a diagram showing an example of display based on the soundness evaluation data D generated by the soundness evaluation data generation unit 212. Fig. 7 is shown as a graph in which the left vertical axis indicates the impact vibration test amplitude, the right vertical axis indicates the spectrum waveform amplitude, and the horizontal axis indicates the vibration frequency. The vibration frequency may also be indicated by frequency. The soundness evaluation data D shown in Fig. 7 is an example of the test results carried out to explain the present invention.

[0050] As shown in Figure 7, the soundness evaluation data generation unit 212 generates soundness evaluation data D by overlaying a spectral waveform S0 including the natural frequency of an arbitrary pier 51 measured by the impact vibration test shown in Figure 3 and a first spectral waveform S1 corresponding to an arbitrary pier 51 generated by the spectral analysis unit 211 shown in Figure 6 on the same frequency axis to enable comparison.

[0051] In this embodiment, to enable comparison between the spectral waveform S0 and the first spectral waveform S1, the soundness evaluation data generation unit 212 adjusts the frequency scale on the horizontal axis of the spectral waveform S0 so that it is the same as the frequency scale on the horizontal axis of the first spectral waveform S1. The soundness evaluation data generation unit 212 then adjusts the frequency scale on the horizontal axis of the spectral waveform S0 so that it is the same as the peak of the impact vibration test amplitude on the vertical axis of the first spectral waveform S1. The soundness evaluation data generation unit 212 then overlays the scale-adjusted spectral waveform S0 on the first spectral waveform S1, thereby enabling comparison on a single screen between the spectral waveform S0 containing the natural frequency of an arbitrary pier 51 measured by the impact vibration test and the first spectral waveform S1 corresponding to the arbitrary pier 51 generated by the spectrum analysis unit 211. This allows the operator to easily evaluate the soundness of the pier 51 by visually comparing the spectral waveform S0 (which may be only the natural frequency) of the pier 51 obtained by the impact vibration test with the first spectral waveform S1 corresponding to any pier 51 generated by the spectral analysis unit 211.

[0052] In the soundness evaluation data D shown in FIG. 7, the natural frequency of the spectrum waveform S0 corresponding to the pier 51 measured by the impact vibration test is "10.74 Hz," and the natural frequency of the first spectrum waveform S1 corresponding to an arbitrary pier 51 determined by the spectrum analysis unit 211 is "10.82 Hz." Therefore, it can be visually confirmed that the natural frequency of the first spectrum waveform S1 corresponding to an arbitrary pier 51 determined by the spectrum analysis unit 211 is almost the same as the natural frequency of the spectrum waveform S0 corresponding to the pier 51 measured by the impact vibration test. This allows the operator to easily evaluate the soundness of the pier 51 by comparing the spectrum waveform S0 (or only the natural frequency) obtained by the impact vibration test with the first spectrum waveform S1 obtained from the results of the spectrum analysis of the microtremor data.

[0053] FIG. 8 is a diagram showing an example of a time-series change in the natural frequency, which is the peak of the spectral waveform displayed on the display unit 34 of the display terminal 30. The operator can instruct the display terminal 30 to display the time-series change in the natural frequency shown in FIG. 8. FIG. 8 is a graph showing the frequency (Hz) of the natural frequency on the vertical axis and the time on the horizontal axis. As shown in FIG. 8, the frequency of the natural frequency changes from F1 to F2 from time t3 to time t4. From this, the operator can determine that the soundness of the pier 51 has changed based on the change in the natural frequency of the pier 51. For example, in the embodiment of FIG. 8, the soundness is determined based on how the frequency of the natural frequency changes. In the example shown in FIG. 8, the natural frequency drops from F1 to F2 from time t3 to time t4. In this case, if an event such as flooding due to heavy rain occurs between time t3 and time t4, it can be determined that the flooding has had some effect on the soundness of the pier 51. In this way, without going to the site where the bridge pier 51 to be evaluated for soundness is installed and conducting a new impact vibration test, the soundness of the bridge pier 51 can be constantly monitored remotely by remotely capturing the continuous microtremor data output from the acceleration sensor 10 and displaying the display image showing the time-series change in the natural frequency shown in Figure 8 on the display terminal 30.

[0054] In addition, in this embodiment, the evaluation section extraction unit 213 extracts multiple evaluation sections from the microtremor data C, and generates and displays soundness evaluation data D that compares multiple spectral waveforms Sn corresponding to the multiple evaluation sections with the spectral waveform S0 obtained from the impact vibration test.

[0055] 9 is a diagram showing another example of time-series changes in the microtremor data C stored in the microtremor data storage unit 222. The microtremor data C is represented by a graph in which the vertical axis represents the acceleration of the acceleration sensor 10 and the horizontal axis represents time.

[0056] The evaluation interval extraction unit 213 extracts microtremor data C1 corresponding to the first evaluation interval F1 and microtremor data C2 corresponding to the second evaluation interval F2 from the microtremor data C. The first evaluation interval F1 illustrated in FIG. 9 is an interval indicated by the interval from time t1 to time t2. Therefore, the microtremor data C1 is the acceleration output from the acceleration sensor 10 from time t1 to time t2. The second evaluation interval F2 illustrated in FIG. 9 is an interval indicated by the interval from time t5 to time t6. Therefore, the microtremor data C1 is the acceleration output from the acceleration sensor 10 from time t1 to time t2, and the microtremor data C2 is the acceleration output from the acceleration sensor 10 from time t5 to time t6.

[0057] The first evaluation section F1 and the second evaluation section F2 are arbitrary sections (arbitrary sections) specified by the operator on the display terminal 30. For example, the first evaluation section F1 and the second evaluation section F2 are sections before and after an event occurrence section related to the pier 51.

[0058] For example, if a first evaluation section F1 and a second evaluation section F2 are specified by an operator's operation on the display terminal 30, the display terminal 30 accepts input of information about the first evaluation section F1 and the second evaluation section F2 and transmits the accepted information about the first evaluation section F1 and the second evaluation section F2 to the server 20. The spectrum analysis unit 211 extracts microtremor data C1 corresponding to the first evaluation section F1 and microtremor data C2 corresponding to the second evaluation section F2. The spectrum analysis unit 211 performs spectral analysis of the extracted microtremor data for the first evaluation section F1 using a fast Fourier transform (FFT) or the like to generate a first spectral waveform S1, and also performs spectral analysis of the extracted microtremor data for the second evaluation section F2 to generate a second spectral waveform S2. The spectrum analysis unit 211 sends the generated first spectral waveform S1 and second spectral waveform S2 to the soundness evaluation data generation unit 212.

[0059] The second spectral waveform S2 generated from the microtremor data corresponding to the second evaluation section F2 is generated in the same manner as the first spectral waveform S1 generated from the microtremor data corresponding to the first evaluation section F1 shown in Fig. 6. Therefore, a detailed explanation of the generation of the second spectral waveform S2 generated from the microtremor data corresponding to the second evaluation section F2 will be omitted.

[0060] The soundness evaluation data generation unit 212 generates soundness evaluation data D for an arbitrary section by comparing a spectral waveform S0 (natural frequency) of the pier 51 measured in advance by an impact vibration test in which an impact is applied to the pier 51 with a first spectral waveform S1 and a second spectral waveform S2 generated by the spectrum analysis unit 211. The soundness evaluation data generation unit 212 generates display data as soundness evaluation data D for displaying a comparison between the spectral waveform S0 including the natural frequency of the pier 51 measured by the impact vibration test and the first spectral waveform S1 corresponding to the first evaluation section F1 and the second spectral waveform S2 corresponding to the second evaluation section F2 generated by the spectrum analysis unit 211. The generated soundness evaluation data D is transmitted to the display terminal 30 via the communication unit 23.

[0061] Fig. 10 is a diagram showing an example of display based on the soundness evaluation data D generated by the soundness evaluation data generation unit 212. Fig. 10 is shown as a graph in which the left vertical axis indicates the impact vibration test amplitude, the right vertical axis indicates the spectrum waveform amplitude, and the horizontal axis indicates the vibration frequency. The vibration frequency may also be indicated by frequency. The soundness evaluation data D shown in Fig. 10 is an example of the test results conducted to explain the present invention.

[0062] As shown in Figure 10, the soundness evaluation data generation unit 212 generates soundness evaluation data D, which is an evaluation image that compares a spectral waveform S0 containing the natural frequency of the pier 51 obtained by the impact vibration test shown in Figure 3, a first spectral waveform S1 corresponding to the first evaluation section F1, and a second spectral waveform S2 corresponding to the second evaluation section F2.

[0063] To enable comparison between the spectral waveform S0, the first spectral waveform S1, and the second spectral waveform S2, the health evaluation data generation unit 212 adjusts the frequency scale on the horizontal axis of the spectral waveform S0 to match the frequency scale on the horizontal axis of the first spectral waveform S1 and the second spectral waveform S2 by enlarging or reducing them.The health evaluation data generation unit 212 also adjusts the peak of the impact vibration test amplitude on the vertical axis of the spectral waveform S0 to match the peak of the spectral waveform amplitude on the vertical axis of the first spectral waveform S1 and the peak of the spectral waveform amplitude on the vertical axis of the second spectral waveform S2 by enlarging or reducing them. The soundness evaluation data generation unit 212 then generates display image data in which the scale-adjusted spectral waveform S0, the first spectral waveform S1, and the second spectral waveform S2 are superimposed, thereby generating soundness evaluation data D that compares the spectral waveform S0, including the natural frequency of the pier 51 obtained by the impact vibration test, with the first spectral waveform S1 and the second spectral waveform S2 of the pier 51 corresponding to the first evaluation section F1 and the second evaluation section F2. This allows the operator to easily visually compare the spectral waveform S0, indicating the natural frequency of the pier 51 obtained by the impact vibration test, with the first spectral waveform S1 and the second spectral waveform S2, indicating the natural frequency of the pier 51, generated by the spectrum analysis unit 211. As a result, the operator can intuitively evaluate the soundness of the pier 51 before and after the event occurrence section.

[0064] In the soundness evaluation data D shown in FIG. 10, the natural frequency of the spectrum waveform S0 corresponding to the pier 51 measured by the impact vibration test is 10.74 Hz. The spectrum analyzer 211 determines that the natural frequency of the first spectrum waveform S1 in the first evaluation section F1 corresponding to an arbitrary pier 51 is 10.82 Hz, and the natural frequency of the second spectrum waveform S2 in the second evaluation section F2 is 9.58 Hz. Therefore, it can be visually confirmed that the natural frequency of the first spectrum waveform S1 in the first evaluation section F1 before the event occurs for the arbitrary pier 51 is almost the same as the natural frequency of the spectrum waveform S0 corresponding to the pier 51 measured by the impact vibration test. On the other hand, it can be visually confirmed that the natural frequency of the second spectrum waveform S2 in the second evaluation section F2 after the event occurs is different from the natural frequency of the spectrum waveform S0 corresponding to the pier 51 measured by the impact vibration test. In the embodiment of FIG. 10 , the natural frequency of the second spectral waveform S2, 9.58 Hz, is lower than the natural frequency of the first spectral waveform S1, 10.82 Hz. Furthermore, the operator can visually recognize that the shape of the second spectral waveform S2 in the second evaluation section F2 after the event occurrence is different from the shape of the first spectral waveform S1 in the first evaluation section F1 before the event occurrence. Therefore, the operator can intuitively grasp that the soundness of the pier 51 is deteriorating in accordance with the change in the peak (natural frequency) of the spectral waveform and the change in the shape of the spectral waveform. By visually displaying the generated soundness evaluation data D, the operator can visually compare the results obtained by the impact vibration test with the first spectral waveform S1 and the second spectral waveform S2 corresponding to a given pier 51, calculated by the spectrum analysis unit 211, and intuitively evaluate the soundness of the pier 51 before and after the event occurrence section.

[0065] Therefore, by spectrally analyzing the microtremor data transmitted from the acceleration sensor 10 to obtain first and second spectral waveforms S1 and S2, in which peaks appear at the natural frequency of the pier 51, and comparing these spectral waveforms with the natural frequency of the pier 51 measured by an impact vibration test, it is possible to generate soundness evaluation data D that can be used to evaluate the soundness of the pier 51. The soundness evaluation data D is generated based on the results obtained by the impact vibration test and on the first and second spectral waveforms S1 and S2, in which peaks appear at the natural frequency of the pier 51, obtained by spectrally analyzing the microtremor data. Therefore, by having an operator visually evaluate the soundness evaluation data D, it can be easily compared with the results obtained by the impact vibration test, and as a result, the operator can intuitively evaluate the soundness of the pier 51.

[0066] As shown in the above-described embodiment, the communication unit 23 of the server 20 receives microtremor data transmitted from the acceleration sensor 10 provided on the pier 51, and the spectrum analysis unit 211 performs spectrum analysis on the microtremor data received by the communication unit 23 to generate a spectral waveform in which a peak appears at the natural frequency of the pier 51. The soundness evaluation data generation unit 212 generates soundness evaluation data D by comparing the natural frequency of the pier 51 measured by an impact vibration test in which impacts are applied to the pier 51 with the spectral waveform generated by the spectrum analysis unit 211. The communication unit 23 transmits the soundness evaluation data D generated by the soundness evaluation data generation unit 212. The display terminal 30 then displays the soundness evaluation data D transmitted from the communication unit 23. This allows the operator to easily compare and visually check the results obtained by the impact vibration test. As a result, the operator can intuitively evaluate the soundness of the pier 51.

[0067] The present invention is not limited to the above-described embodiments, and the components can be modified and embodied in practice without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining the multiple components disclosed in the above-described embodiments. For example, all of the components shown in the above-described embodiments can be appropriately combined. Naturally, various modifications and applications are possible without departing from the spirit of the invention. [Explanation of symbols]

[0068] 1: Pier soundness evaluation system 10: Acceleration sensor 11: Gateway 20: Server 21: Control unit 22: Storage section 23: Communications Department 30: Display terminal 31: Control unit 32: Storage section 33: Input section 34: Display section 35: Communications Department 50: Bridge 51: Bridge pier 211: Spectral analysis unit 212: Soundness evaluation data generation unit 213: Evaluation section extraction unit 221: Impact vibration test data storage unit 222: Microtremor data storage unit N: Network

Claims

1. A bridge pier soundness evaluation system comprising a server and a display terminal that communicates with the server, The server a receiving unit that receives microtremor data transmitted from an acceleration sensor installed on the bridge pier; an analysis unit that performs spectral analysis on the microtremor data received by the receiving unit to generate a spectral waveform in which a peak appears at the natural frequency of the bridge pier; a soundness evaluation data generation unit that generates soundness evaluation data by comparing the natural frequency of the pier measured by an impact vibration test that applies impact to the pier with the spectral waveform; a transmission unit that transmits the soundness evaluation data generated by the soundness evaluation data generation unit, The display terminal Displaying the health evaluation data transmitted from the transmission unit A bridge pier soundness evaluation system characterized by the above.

2. The display terminal transmitting a first evaluation interval and a second evaluation interval arbitrarily designated by an operator to the server; The server Generate the soundness evaluation data for an arbitrary section by comparing a first spectral waveform generated from the microtremor data corresponding to the first evaluation section, a second spectral waveform generated from the microtremor data corresponding to the second evaluation section, and the natural frequency of the pier measured by the impact vibration test, and transmit the generated soundness evaluation data to the display terminal.

2. The bridge pier soundness evaluation system according to claim 1.

3. The first evaluation section and the second evaluation section are sections before and after the event occurrence section related to the pier.

3. The bridge pier soundness evaluation system according to claim 2.

4. a receiving unit that receives microtremor data transmitted from an acceleration sensor installed on the bridge pier; an analysis unit that performs spectral analysis on the microtremor data received by the receiving unit to generate a spectral waveform in which a peak appears at the natural frequency of the bridge pier; a soundness evaluation data generating unit that generates soundness evaluation data by comparing the natural frequency of the pier measured by an impact vibration test that applies impact to the pier with the spectral waveform. A bridge pier soundness evaluation device characterized by the above.

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