JP2015094733A - Determination method for structure state change, correction method for measurement data, and instrumentation system using methods - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a determination method for structure state change capable of determining the state change of a structure in real time in an instrumentation system comprising terminals and a server connected with instrumentation devices installed in the structure via a network.SOLUTION: The determination method for structure state change comprises steps of: setting a transfer function for correlating the physical quantities of each instrumentation device in an instrumentation system in which a first instrumentation device including a first sensor and a second instrumentation device including a second sensor are connected via a network and are installed in each structure to be measured; measuring the acceleration in each instrumentation device; calculating a displacement simulation value on the basis of the acceleration and transfer function in the first instrumentation device; calculating the number of bits with a different value by comparing bit by bit the displacement simulation value and the displacement in the second instrumentation device in binary representation; and determining the state change of the structure on the basis of the calculated number of bits with a different value.

Description

  The present invention relates to a measurement system in which a plurality of measurement devices installed in a structure such as a building, a bridge, or a dam, and a terminal or server that manages them are connected via a network in real time. The present invention relates to a state change determination method for a structure to be detected and detected, a measurement data correction method, and a measurement system using these methods.

  Multiple seismic intensity sensors such as accelerometers are installed in civil engineering structures such as bridges or building structures (hereinafter referred to as “structures”), and the vibration of each part of the structure is measured when an earthquake occurs. A residual seismic performance evaluation system that transmits the measurement data to a management server and evaluates the residual seismic performance of the building from the displacement amount of the building calculated from the measurement data and the design data of the structure is known (Patent Document 1). ).

JP 2011-95237 A

  In the conventional residual seismic performance evaluation system, after a certain amount of measurement data is accumulated on the server side, the residual seismic performance of the structure is evaluated from the measurement data. It was not known until after the ex-post evaluation of the residual seismic performance of the structure by analyzing the measured data. Therefore, there is a problem that a huge amount of measurement data is accumulated regardless of whether the structure has changed state.

  In addition, the present inventors have confirmed that a time lag occurs with the passage of time between the measurement data of each measurement base, and if the measurement data including the time lag is used as it is, the structure is naturally analyzed accurately. There was a problem that could not be done.

  The present invention has been made in view of the above, and in a measurement system in which a measurement device installed in a structure and a terminal or a server are connected via a network, a state change of the structure is determined in real time. It is a main technical problem to provide a state change determination method and a measurement data correction method that can suppress the influence of a time shift of measurement data.

  The structure state change determination method according to the present invention includes a CPU, a storage unit that stores a program and data, and a first sensor that includes a first sensor that measures a physical quantity related to an earthquake at an installed point; A second measuring device comprising a CPU, storage means for storing a program and data, and a second sensor for measuring a physical quantity relating to an earthquake at an installed point; a terminal or server for recording and processing measurement data; Is a state change determination method for a structure in a measurement system in which the first and second measurement devices are respectively arranged in the structure to be measured, the physical quantity in the first measurement device. And a step S1 for setting a transfer function relating the physical quantity in the second measuring device, and a first addition by the first sensor. A step S2 of measuring the second acceleration by the second sensor, calculating a displacement value based on the first acceleration and the transfer function, and calculating the second acceleration based on the second acceleration. In step S5 for calculating the displacement, a binary value of the simulated displacement value and a binary value of the displacement calculated based on the second acceleration are compared with each other, and different bit values are obtained. Step S6 for calculating the number and Step S7 for determining the state change of the structure based on the calculated number of different bits.

  Here, the first and second sensors refer to sensors that primarily detect physical quantities related to earthquake shaking, such as acceleration sensors, velocity sensors, or displacement sensors. The measurement data is measurement data (raw data) recorded by the first or second sensor. For example, when the first sensor is an acceleration sensor, the time and acceleration data recorded by the first measurement device may be used. In addition, the transfer function indicates the transfer characteristic between the measurement points of the structure at the time of shaking such as an earthquake. The transfer function does not change while the structure is linearly deformed. Therefore, by detecting that the transfer function has changed, it is possible to detect and detect that the structure has been destroyed and changed to non-linear deformation, that is, the state change of the structure. For example, the transfer function may be an expression indicating the relationship between the acceleration in the first measurement device and the acceleration in the second measurement device, and the acceleration measured by the first measurement device by using this transfer function. From the above, it is possible to calculate acceleration, velocity and displacement in the second measuring device. The target structure undergoes linear deformation within a certain range due to shaking such as an earthquake, and it is preferable that the change from the linear deformation to the non-linear deformation is relatively easy to find. Etc.

  According to such a configuration, each bit of the binary value of the displacement calculated using the first acceleration and the transfer function is compared with each bit of the binary value of the displacement calculated based on the second acceleration. In order to determine the state change of the structure based on the number of different bits, there is no need to accumulate a certain amount of measurement data from each measuring device, and the state change of the structure can be determined in real time during measurement. it can. This eliminates the need to store a large amount of measurement data after a state change occurs in the structure, and promotes effective use of storage and network resources for storing the measurement data.

  Depending on the structure of the structure, the magnitude of shaking such as an earthquake and the accuracy of the measurement data and transfer function, the displacement calculated based on the simulated value of the displacement and the second acceleration are all represented by signed 24 bits. While the structure is linearly deformed, the number of different bits is about 3 to 5, and the number of identical bits is about 80 to 90% of the whole. Therefore, for example, when the number of different bits is 4 or more, it may be determined that a state change has occurred in the structure.

  In the structure state change determination method, the transfer function is set for each speed condition, and the transfer function is calculated using a speed calculated based on the measured acceleration when calculating a simulated displacement value. A function may be selected. Specifically, the transfer function may be approximated by two quadratic curves when the speed is 0 or more and when the speed is less than 0. When a structure is linearly deformed due to shaking such as an earthquake, the transfer function can be expressed by approximating a closed curve (substantially elliptical) that is symmetric with respect to a certain straight line on a plane showing the relationship between acceleration and displacement. I know I can. If this transfer function is expressed by two kinds of quadratic curves when the speed is 0 or more and when the speed is less than 0, the transfer function is expressed more simply and the state change of the structure is more efficiently determined. be able to.

  A measurement data correction method according to the present invention includes a CPU, a storage unit that stores a program and data, a first measurement device that includes a first sensor that measures a physical quantity relating to an earthquake at an installed point, and a CPU. A second measuring device comprising a storage means for storing a program and data and a second sensor for measuring a physical quantity relating to an earthquake at an installed point, and a terminal and a server for recording and processing the measured data Are connected to each other, and the first and second measuring devices are arranged in the structure to be measured, respectively, in the measurement data correction method, and the physical quantity in the first measuring device and the second A step of setting a transfer function for relating a physical quantity in the measuring device, and the first measuring device using the transfer function Calculating the time lag of the second measurement data in the second measurement device with respect to the first measurement data; and linearly according to the time of the second measurement data based on the time lag And a time shift correction step of correcting the time of the second measurement data.

  According to such a configuration, the time shift of the second measurement data in the second measurement device with respect to the first measurement data in the first measurement device using the transfer function, specifically, the structure is In order to calculate the time lag that occurs between the measurement data during the state change, and to linearly correct the time of the second measurement data based on the time lag of the second measurement data based on the time lag, The time of the second measurement data can be synchronized with the time of the first measurement data so as to suppress the influence of the time lag of the measurement data. Thereby, a structure can be analyzed more correctly by using these measurement data.

A measurement system according to the present invention includes a first measurement device including a first sensor that measures a physical quantity related to an earthquake, a second measurement device including a second sensor that measures a physical quantity related to an earthquake, and measurement data. Including a terminal and a server for recording and processing, and a network connecting them, and causing the terminal or the server to execute the following steps.
a set a transfer function relating the physical quantity in the first measuring device and the physical quantity in the second measuring device b measured by the first acceleration measured by the first sensor and the second sensor C) receiving a second acceleration; c) calculating a displacement value based on the first acceleration and the transfer function and calculating a displacement value based on the second acceleration. The number of different bits is calculated by comparing each bit of the binary value of the displacement and the binary value of the displacement calculated based on the second acceleration. E Structure based on the calculated number of different bits Determining changes in the state of things

  According to such a configuration, the binary value of the displacement calculated using the transfer function and the binary value of the received displacement are compared with each other, and the structure is based on the number of different bits. Therefore, it is not necessary to accumulate a certain amount of measurement data received from each measuring device, and if the measurement data is received, the state change of the structure can be determined in real time during measurement.

  According to the state change determination method according to the present invention, each bit of the binary value of the displacement calculated using the first acceleration and the transfer function and the binary value of the displacement calculated based on the second acceleration. Since the state change of the structure is determined based on the number of different bits by comparing each other, the state change of the structure can be determined in real time at the time of measurement.

  According to the measurement data correction method of the present invention, the time difference of the second measurement data is calculated with respect to the first measurement data using the transfer function, and the time of the second measurement data is calculated based on the time difference. Since the time of the second measurement data is linearly corrected in accordance with the time, the time of the second measurement data is less affected by the time difference of the measurement data than the time of the first measurement data. Can be synchronized.

It is a figure which shows the measurement system of 1st Embodiment. It is a figure which shows the 1st measuring device, 2nd measuring device, and data processing terminal of 1st Embodiment. It is a flowchart of the state change determination method of the structure of 1st Embodiment. It is a graph which shows the concept of the transfer function of 1st Embodiment. It is a figure which shows the comparison between each bit of the displacement calculated from the simulated value of displacement and acceleration. It is a figure which shows the block configuration of the 1st measuring device of the measuring system of 1st Embodiment, and a 2nd measuring device, (a) is a figure which shows a 1st measuring device, (b) is a 2nd It is a figure which shows this measuring device. It is a figure which shows the block configuration of the data processing terminal and data processing server of the measurement system of 1st Embodiment, (a) is a figure which shows a data processing terminal, (b) is a figure which shows a data processing server. . It is a graph which shows the transfer function before the state change of a test body, (a) is a graph which shows the transfer function represented by the impulse response using LMS, (b) is a graph which shows the transfer function of Fig.8 (a) at high speed. It is a graph after Fourier-transforming. It is a graph which shows the waveform of the acceleration before the state change of a test body, (a) is a graph which shows an actual response waveform and a prediction waveform, (b) is a graph which expanded the area | region B1 of Fig.9 (a). is there. It is a figure which shows the waveform of the acceleration after the state change of a test body, (a) is a graph which shows an actual response waveform and a prediction waveform, (b) is a graph which expanded the area | region B2 of Fig.10 (a). is there. It is a graph which shows the compression efficiency of differential compression, and the relationship of time. The figure which shows the input waveform in each measuring device Diagram showing an example of the transfer function before and after the state change of the structure Figure showing an example of seismic intensity data before and after the state change of a structure

  Hereinafter, each embodiment of the present invention will be described with reference to the drawings. The same reference numerals are used for the same or similar members, or only the subscripts are displayed differently, and the duplicate description is omitted. However, the description of the present embodiment is for understanding the technical idea of the present invention. Should not be construed as limited to the description of the embodiments.

(First embodiment)
FIG. 1 is a diagram illustrating a measurement system according to the first embodiment. The measurement system 100 may include a plurality of measurement devices 10 and 20, a data processing terminal (hereinafter sometimes simply referred to as “processing terminal”) 30, and a data processing server (hereinafter simply referred to as “processing server”). 50) and a user terminal 70, which are connected via the network 60. The plurality of measuring apparatuses 10 and 20 (20a, 20b,...) And the processing terminal 30 are all connected to a local area network (hereinafter referred to as “LAN”) 40. The processing server 50 processes data relating to a huge earthquake sent from the processing terminal 30. Further, the processing server 50 includes a storage (not shown), in which various data collected by the processing server 50 is recorded and necessary authentication data is stored.

  FIG. 6 is a diagram illustrating a block configuration of the first measurement device 10 and the second measurement device 20 of the measurement system according to the first embodiment. FIG. 6A is a diagram showing the first measuring device 10, and FIG. 6B is a diagram showing the second measuring device 20 (20a, 20b,...). As shown in FIG. 6A, the first measuring apparatus 10 includes a CPU 11 that controls the entire apparatus, a storage device 12 such as a flash memory and a hard disk, a temporary storage means 13 such as a RAM, a network interface 14, and the like. The A / D converter 15 and the acceleration sensor 16 are provided in one housing. As shown in FIG. 6B, the second measuring apparatus 20 includes a CPU 21 that controls the entire apparatus, a storage device 22 such as a flash memory and a hard disk, a temporary storage means 23 such as a RAM, and a network interface. 24, an A / D converter 25, an acceleration sensor 26, and the like are provided in one housing. A plurality of second measuring devices 20 having the same configuration are provided for one measuring object (structure).

  The storage device 12 (22) records an OS and a program for measurement, and stores a calculation result by the CPU 11 (21) as data. The acceleration sensor 16 is connected to the CPU 11 via the A / D converter 15 and transmits the acceleration measurement value to the CPU 11 while sampling. Similarly, the acceleration sensor 26 samples the measured acceleration value and transmits it to the CPU 21.

  The first measuring device 10 includes three acceleration sensors 16 and can measure acceleration corresponding to three axes in the horizontal (XY direction) and vertical (Z direction) in real time. The second measuring device 20 includes three acceleration sensors 26, and can measure acceleration corresponding to three axes in the horizontal (XY direction) and vertical (Z direction) in real time. Since acceleration, speed, and displacement are in an integral or differential relationship, each of the sensors may theoretically be an acceleration sensor, a speed sensor, or a displacement sensor.

  FIG. 7 is a diagram illustrating a block configuration of the data processing terminal 30 and the data processing server 50 of the measurement system according to the first embodiment. FIG. 7A is a diagram showing a data processing terminal, and FIG. 7B is a diagram showing a data processing server. As shown in FIG. 7A, the data processing terminal 30 may be a general-purpose computer provided with a CPU 31, a storage device 32, a RAM 33, a network interface 34, etc., and a predetermined data processing terminal program installed therein. . The CPU 31 executes a program for compressing the acceleration data measured by the first measuring device 10 using the acceleration data measured by the second measuring device 20, and also the time between the measuring devices (10, 20). For example, a program for correcting measurement data, a program for correcting measurement data, and a program for recording only necessary data in the storage device 32 and transmitting the data to the data processing server 50. The storage device 32 records the OS and various programs, and stores seismic intensity data and acceleration data. Of course, the storage device 32 may be a file server or the like provided in the LAN 40 or the like.

  The data processing terminal 30 is installed outside the building 1 and connected to the LAN 40. The data processing terminal 30 mainly plays a role of managing the measuring devices 10 and 20, and it is sufficient that at least one data processing terminal 30 is provided for one structure in which the plurality of measuring devices 10 and 20 are installed. However, even if the processing terminal 30 is omitted by having at least one of the measuring devices 10 and 20 also have the function of the processing terminal 30 and using this as the “master unit” and other measuring devices as the “slave unit”. Good. Alternatively, all the measuring devices may have a processing terminal function.

  As shown in FIG. 7B, the data processing server 50 may be a general-purpose computer provided with a CPU 51, a storage device 52, a RAM 53, a network interface 54, etc., and a predetermined data processing server program installed therein.

  FIG. 2 is a diagram illustrating the first measurement device 10, the second measurement device 20, and the data processing terminal 30 according to the first embodiment. The first measuring device 10 is installed on the floor of the first floor (the ground floor) in the building 1 as a measurement reference point, and is connected to the LAN 40. The second measuring devices 20 (20a, 20b,...) Are respectively installed on the floors of the second floor and above in the building 1 and connected to the LAN 40, respectively. The data processing terminal 30 is installed outside the building 1 and connected to the LAN 40. The building 1 may be a structure that linearly deforms due to an earthquake or the like, and it is preferable that the change from linear deformation to non-linear deformation is easily identified. Specifically, the building 1 preferably has a reinforced concrete structure rather than a wooden structure. The building 1 may be a leg of a bridge.

  In this building 1, when the acceleration Pa is measured in the first measuring device 10 which is the reference point due to a shake such as an earthquake, the displacement Xma relative to the first measuring device 10 in the second measuring device 20a. Is measured, and the displacement Xmb relative to the first measurement device 10 is measured in the second measurement device 20b.

  Hereinafter, the structural state change determination method according to the first embodiment will be briefly described with reference to the building 1, the first measurement device 10, and the second measurement device 20 a in FIG. 2. The time of the first measuring device 10 and the time of the second measuring device 20a are synchronized, and unless otherwise specified, the acceleration of the first measuring device 10 and the acceleration of the second measuring device 20a are the same time. Refers to things. Further, in the state change determination method, the acceleration is determined for each state of the structure (building 1) in each direction after measurement with respect to the three axes of the horizontal (XY direction) and vertical (Z direction). However, in the following description, only the X direction is described, and the Y and Z directions are the same as the X direction, and the description is omitted.

FIG. 3 is a flowchart of the structure state change determination method according to the first embodiment.
First, a transfer function f that relates the acceleration Pa in the first measurement device 10 (first acceleration sensor system) and the displacement Xa in the second measurement device 20a (second acceleration sensor system) is set (step S1). ). This transfer function f is prepared in advance.

  FIG. 4 is a graph showing the concept of the transfer function f of the first embodiment. As shown in FIG. 4, the transfer function f is a closed curve (symmetrical with respect to a certain straight line L on a plane in which the vertical axis is the acceleration Pa and the horizontal axis is the displacement Xa in a state where the building 1 holds the linear deformation. (Approximate elliptical) can be approximated. If the transfer function f is expressed by a mathematical expression with the acceleration Pa as a variable, the displacement Xa can be calculated from the acceleration Pa using the transfer function f. In addition, when the building 1 is a hard structure, the transfer function f has a smaller distance to the straight line L as a whole, and approaches the straight line L.

For example, when the transfer function f is roughly divided into two in accordance with the sign of the speed Pv of the first measuring device 10 and expressed by a quadratic curve fp (Pv ≧ 0) and fn (Pv <0), the speed Pv When ≧ 0, the displacement Xa can be calculated by the following equation (1) using the acceleration Pa and the transfer function fp.
Xa = fp (Pa) (1)

  The transfer function f (fp and fn) is prepared in advance by an approximate expression based on the measured acceleration value by the first measuring device 10 and the measured acceleration value by the second measuring device 20a. For example, the transfer function f may be expressed by a mathematical expression by an algorithm such as LMS (Least Mean Square) using a finite impulse response (FIR). If the building 1 is sufficiently rigid, the transfer function can be approximately expressed using the LMS algorithm on the premise of linear deformation of the building 1, but the algorithm used depending on the structure (property) of the building 1 It is necessary to change the transfer function.

Specifically, the acceleration Pa may be expressed by the following equation (2) using a finite impulse response, and the coefficient hm (n) may be determined by an algorithm such as LMS.
Xa (n) = Σhm (n) · Pa (nm) (2)
Where Pa (n) is an input signal, Xa (n) is an output signal, hm (n) is a weighting factor of Pa (n), and m = 0, 1,..., N−1. Is an integer.

  Next, the first measuring device 10 measures the acceleration Pa, and the second measuring device 20a measures the acceleration Pma corresponding to the acceleration Pa (step S2). When processing is performed on the data processing terminal 30 or the data processing server 50 side, the data of the measured accelerations Pa and Pma are received. The accelerations Pa and Pma are 24 bit data. Although the acceleration Pa and the displacement Xma are measured in the three-axis (X, Y, Z) directions, respectively, only the two-axis (X, Y) directions may be used.

  Next, when the transfer function f is expressed in two ways, fp (Pv ≧ 0) or fn (Pv <0), the speed Pv is calculated based on the acceleration Pa of the first measuring device 10 (step S3), fp or fn is selected as the transfer function f based on the calculated speed Pv (step S4). When calculating the speed Pv, noise may be removed using a noise removal filter or the like. Note that steps S3 and S4 are not required when the transfer function f is expressed by one mathematical expression or when it is not expressed by a mathematical expression for each predetermined range of the speed Pv.

  Next, a displacement simulation value Xa in the second measuring apparatus 20a is calculated using the measured acceleration Pa and the transfer function f. Further, the displacement Xma in the second measuring device 20a is calculated based on the measured acceleration Pma (step S5).

  Next, each bit of the binary value of the simulated displacement value Xa and the binary value of the displacement Xma is compared (step S6). At this time, the number N of different bits is calculated by comparing each bit.

  FIG. 5 is a diagram illustrating a comparison between each bit of the simulated displacement Xa and the displacement Xma calculated from the acceleration. As shown in FIG. 5, the simulated displacement value Xa expressed in binary number and the displacement Xma value expressed in binary number are compared with each other, and the total number of Ds indicating different bits is expressed as N. And When comparing each bit, lower 4 bits having a large influence of noise may be excluded.

  The comparison between the bits may be performed when the same processing is performed, specifically, when the displacement Xma is differentially compressed using the simulated displacement value Xa. In this case, the value obtained by subtracting the number N of different bits from the total number of bits (24) can be considered as the compression efficiency of differential compression in terms of the overall ratio.

  Next, the state change of the building 1 is determined based on the number N of different bits (step S7). When the building 1 is linearly deformed due to shaking such as an earthquake, the number N of different bits is small, but when the building 1 is destroyed and deformed nonlinearly, this N becomes large. Therefore, for example, when the number N of different bits becomes a certain value or more, it is determined that a state change has occurred in the building 1.

  Further, the compression efficiency of the differential compression is maintained at about 80 to 90% while the building 1 is linearly deformed due to shaking such as an earthquake. However, when the building 1 is destroyed and begins to deform nonlinearly, the compression efficiency is increased. Decrease significantly. Therefore, in this case, it is determined that a state change has occurred in the building 1.

  Through steps S1 to S7, the acceleration Pa is measured by the first measuring device 10 and the acceleration Pma corresponding to the acceleration Pa is measured by the second measuring device 20a, and the number N of the different bits or the differential compression is calculated. By looking at the time-series change in compression efficiency, it is possible to determine the change in the state of the building 1 in real time during measurement.

  In addition to the number N of different bits and the compression efficiency of the differential compression, the ratio STA / LTA between the short time average STA and the long time average LTA of the second measuring device 20a is calculated using the transfer function f. It may be calculated and the time series change of the ratio STA / LTA may be seen, and the state change of the building 1 can be similarly determined.

  Note that steps S1 to S7 may be performed by either the data processing terminal 30 or the data processing server 50, or may be performed by the first measuring device 10 or the second measuring device 20a.

  Here, an experiment was performed in which a steel rack having a three-stage configuration was actually used as a test body to determine and detect a change in the state of the test body. First, the first measuring device 10 (input side) is installed in the first stage of the test body, and the second measuring device 20 (response side) is installed in the third stage, and a certain acceleration is applied to the test body. The transfer function before the state change of the specimen (hereinafter referred to as “before the state change”) was approximately expressed by an impulse response using an LMS algorithm. Then, the transfer function was subjected to Fast Fourier Transform (FFT), and the band (frequency) pass characteristic of the transfer function was examined.

  FIG. 8 is a graph showing a transfer function before the state change of the specimen. FIG. 8A is a graph showing a transfer function represented by an impulse response using LMS, and FIG. 8B is a graph after fast Fourier transform of the transfer function of FIG. 8A. In FIG. 8A, the horizontal axis represents the number of steps (1 step = 10 [ms]), and the vertical axis represents the gain (output signal / input signal) of the transfer function. In FIG. 8B, the horizontal axis represents frequency [Hz], and the vertical axis represents transfer function gain (output signal / input signal).

  As shown in FIG. 8B, it can be seen that the band pass characteristic of the transfer function is transmitted through the lower frequency region. In particular, it can be seen that the pass characteristic up to about 0 to 5 [Hz] is good. On the other hand, using this transfer function, it can be seen that noise in the high frequency region included in the input waveform of the first measurement device 10 and the response waveform of the second measurement device 20 is difficult to be transmitted.

  Thereafter, the actual response of the second measurement device 20 is applied to each of the specimen before the state change of the specimen and after the state change of the specimen (hereinafter referred to as “after the state change”). A waveform (hereinafter referred to as “response waveform”) and a predicted waveform (hereinafter referred to as “predicted waveform”) of the second measuring apparatus 20 were examined. In addition, the state after the state change of the test body was a state in which each fixing screw of the test body was loosened. The response waveform is an actual measured value of acceleration in the second measuring device 20, and the predicted waveform is calculated using the actual measured value of acceleration in the first measuring device 10 based on the transfer function of FIG.

FIG. 9 is a diagram showing a waveform of acceleration before the state change of the specimen. FIG. 9A is a graph showing an actual response waveform and a predicted waveform, and FIG. 9B is a graph in which the region B1 in FIG. 9A is enlarged. 9A and 9B, the horizontal axis represents the number of steps (1 step = 10 [ms]), and the vertical axis represents the acceleration gal [cm / s ² ] normalized to ± 1. Each is shown.

  As shown in FIGS. 9 (a) and 9 (b), it can be seen that the predicted waveform approximates the response waveform as a whole before the state change of the specimen.

FIG. 10 is a diagram showing a waveform of acceleration after the state change of the specimen. FIG. 10A is a graph showing an actual response waveform and a predicted waveform, and FIG. 10B is a graph in which the region B2 in FIG. 10A is enlarged. 10A and 10B, the horizontal axis represents the number of steps (1 step = 10 [ms]), and the vertical axis represents the acceleration gal [cm / s ² ] normalized to ± 1. Each is shown.

  As shown in FIGS. 10 (a) and 10 (b), it can be seen that the predicted waveform is greatly different from the response waveform as a whole after the state change of the specimen. This is because the transfer function has changed due to a change in the state of the specimen. Therefore, by examining the change of the transfer function, it is possible to determine and detect the trigger before and after the state change of the specimen. Specifically, using this transfer function, the number N of the different bits, the compression efficiency of the differential compression, and the like are examined in time series, and the state change of the specimen near the point where the large change has occurred. It can be considered as the time of occurrence.

  Note that, by smoothing the error between the actual response waveform and the predicted waveform before the state change of the test body, erroneous detection before and after the state change of the test body due to the error can be prevented.

  FIG. 11 is a graph showing the relationship between the compression efficiency of differential compression and time. The relationship between compression efficiency and time at the time of the differential compression is shown in a graph from the data before and after the state change of the specimen. As shown in FIG. 11, the compression efficiency was 80% or more before the state change of the specimen, but after the boundary P (time T [s]), the compression efficiency was greatly reduced to less than 10%. In the experiment, the case where the average of 100 [ms] cannot be maintained at 80% was set as “detection (with state change)”, but in actual operation, stepwise detection (for example, 100 [ms] It is considered better to generate a preliminary trigger when the ms] average cannot maintain 80% and to determine the trigger when the 500 [ms] average cannot maintain 80%. Thus, it was found that by examining the change in compression efficiency, it was possible to detect that a state change occurred in the specimen near the boundary P (time T [s]).

  In the state change determination method in the measurement system of the first embodiment, the binary value of the displacement Xa calculated by using the acceleration Pa and the transfer function f measured by the first measurement device 10, and the second measurement. In order to determine the state change of the building 1 based on the number N of different bits by comparing each bit of the binary value of the displacement Xma measured by the device 20a, the state change of the building 1 is measured in real time at the time of measurement. Can be determined.

(Second Embodiment)
In a residual seismic performance evaluation system that evaluates the residual seismic performance of a building, if a time lag occurs between measuring devices after a predetermined time has elapsed, it is impossible to accurately analyze the structure even if these measurement data are used as they are. In addition, when the time is simply synchronized between the measuring devices, the measurement data immediately after the time synchronization is effective as data for accurately analyzing the structure, but after the time synchronization until the next time synchronization. This measurement data is considered to include some time lag. From the above, in order to analyze the structure more accurately, a method for correcting measurement data in which a time lag has occurred between the measurement apparatuses will be described. This measurement data correction method can also be used in the measurement system of the first embodiment, and will be described below using the measurement system shown in FIGS. 1 and 2 as the measurement system of the second embodiment.

  In the measurement data correction method in the measurement system of the second embodiment, first, a transfer function that relates the physical quantity in the first measurement device 10 and the physical quantity in the second measurement device 20 is described in detail. Similarly to the embodiment, a transfer function f that relates the acceleration Pa in the first measurement device 10 (first acceleration sensor system) and the displacement Xa in the second measurement device 20a (second acceleration sensor system) is set. . This transfer function f is prepared in advance. In the following description, the measurement system of the second embodiment is based on the time of the first measurement device 10.

  Next, a time shift ΔT of the second measurement data in the second measurement device 20 is calculated with respect to the first measurement data in the first measurement device 10 using the transfer function f.

FIG. 12 is a diagram illustrating an input waveform in each measurement apparatus. A solid line waveform W1 indicates an input waveform of the first measurement apparatus, and a broken line waveform W2 indicates an input waveform of the second measurement apparatus. FIG. 13 is a diagram illustrating an example of the transfer function f before and after the state change of the structure. In addition to the solid line, the transfer function f draws a trajectory like a broken line. Here, the time T _D is the time when the structure is changed status.

As shown in FIG. 12, in the measurement system of the second embodiment, time and time of the second measurement device 20 of the first measuring device 10 at time T ₀ it is synchronized. Then, the time difference is calculated after a predetermined time has elapsed. Specifically, it corresponds to the measurement data w ₁ (time T ₁ ) of the first measurement device 10 after the time (T ₁ -T ₀ ) from time T ₀ to time T ₁ has elapsed using the transfer function f. A time shift ΔT of the measurement data w ₂ (time T ₂ ) of the second measuring device 20 is calculated.

As shown in FIG. 13, the transfer function f is found to vary greatly not stable before and after the time T _D which has a state change of the structure, for example, prior to the transfer function f is greatly changed the Based on the input waveform W1 of the first measuring device and the input waveform W2 of the second measuring device, the waveforms indicating the transfer characteristics between the first measuring device 10 and the second measuring device 20 are identified and identified. By comparing the characteristic portions of the respective waveforms, the time shift ΔT of the measurement data w ₂ (time T ₂ ) of the second measurement device 20 corresponding to the measurement data w ₁ (time T ₁ ) of the first measurement device 10 is obtained. calculate. As one of the methods for identifying a waveform, there is a method for identifying a waveform by representing a waveform using a finite impulse response as described above and determining a coefficient by an LMS algorithm.

  In a vibration environment with pulse input, the first measurement device calculates a ratio STA1 / LTA1 between the short-time average STA1 and the long-time average LTA1, and similarly, the second measurement device has a short time average STA2 and a long length. The ratio STA2 / LTA2 with the time average LTA2 is calculated. Then, the time shift ΔT may be calculated from a comparison between the ratio STA1 / LTA1 and the ratio STA2 / LTA2. This ratio between short-time average and long-term average indicates the self-similarity of the waveform, and it is easy to extract and compare the time of the moment when the self-similarity is lost by inputting the pulse waveform. Can do. In addition, the vibration environment with this pulse input refers to an environment in which vibration occurs on time, such as mechanical vibration or an iron bridge through which a train passes.

  Next, the time of the second measurement data is linearly corrected according to the time of the second measurement data based on the time difference ΔT of the second measurement data. At this time, seismic intensity data is used to identify a time zone in which the state change of the structure continues.

FIG. 14 is a diagram illustrating an example of seismic intensity data before and after a state change of a structure. As shown in FIG. 14, first extracts a time T _D in which the state change of the structure as a temporary trigger. Incidentally, the time T _D can be used to time it is determined that there is a state change of the structure in the measurement system of the first embodiment. Then extracted end time T ₃ free earthquake state (seismic intensity 0) before a state change of the structure relative to the time T _D of the state change of the structure as a trigger time, the structure as Detoriga time of releasing the trigger the start time T ₄ free Shin state (seismic intensity 0) is extracted after the change of state. Here, the trigger time means a time at which extraction of measurement data is started. Then, when the time t of the measurement system (first measurement device 10) of the second embodiment is between the times (T _{3 to} T ₄ ), the time difference ΔT is set to the time T ₂ (t) of the _second measurement data. Add linearly. For example, when the time t is between the times (T _{0 to} T ₁ ), the correction is performed as in the following formula (3).

T ₂ ′ (t) = T ₂ (t) −ΔT · (t−T ₀ ) / (T ₁ −T ₀ ) (3)
However, T ₂ (t) is the time of the second measurement data before correction of time t, T ₀ = T ₂ (T ₀ ), T ₂ = T ₂ (T ₁ ), and T ₂ '(T) is the time of the second measurement data after correction of time t.

  By correcting the time of the second measurement data as in Expression (3), the time of the second measurement data can be synchronized with the time of the first measurement data. In the measurement system according to the second embodiment, the data processing terminal 30 acquires the first measurement data and the second measurement data after the correction described above, and transmits them to the data processing server 50, thereby performing data processing. The server 50 can analyze the structure more accurately.

  The measurement data correction method in the measurement system of the second embodiment is based on the time lag between the first measurement device and the second measurement device, and the second linearly according to the time of the second measurement data. In order to correct the time of the measurement data, the time of the second measurement data can be synchronized with the time of the first measurement data so as to suppress the influence of the time lag of the measurement data.

10 first measurement device 20 second measurement device 30 data processing terminal 40 LAN
50 data processing server 60 network

Claims (11)

A first measuring device comprising a CPU, a storage means for storing programs and data, and a first sensor for measuring a physical quantity relating to an earthquake at the installed location; a storage means for storing the CPU, programs and data; A second measuring device comprising a second sensor for measuring a physical quantity related to an earthquake at a certain point, and a terminal or server for recording and processing measurement data are connected via a network, and the first and first A method for determining a state change of a structure in a measurement system in which the two measurement devices are arranged in the structure to be measured,
Setting a transfer function for associating a physical quantity in the first measurement device with a physical quantity in the second measurement device;
Step S2 of measuring a first acceleration by the first sensor and measuring a second acceleration by the second sensor;
Calculating a displacement value based on the first acceleration and the transfer function, and calculating a displacement value based on the second acceleration;
A step of calculating the number of different bits by comparing each bit of the binary value of the displacement simulated value and the binary value of the displacement calculated based on the second acceleration;
And a step S7 for determining a state change of the structure based on the calculated number of different bits.   The transfer function is set for each speed condition, and the transfer function is selected by using a speed calculated based on the first acceleration when calculating a simulated value of the displacement. The state change determination method for a structure according to claim 1.   3. The structure state change determination method according to claim 2, wherein the transfer function is approximated by two quadratic curves when the speed is 0 or more and when the speed is less than 0. Both the simulated displacement value and the displacement value calculated based on the second acceleration are 24 bit data,
4. The structure state change determination method according to claim 1, wherein lower 4 bits are excluded when calculating the number of different bits. 5.   5. The number of different bits is calculated when differentially compressing a displacement value calculated based on the second acceleration with a simulated value of the displacement. The structure state change determination method according to any one of the preceding claims. Calculating the compression efficiency of differential compression based on the number of different bits;
6. The structure state change determination method according to claim 5, further comprising a step of determining a state change of the structure based on the calculated compression efficiency. A first measuring device comprising a CPU, a storage means for storing programs and data, and a first sensor for measuring a physical quantity relating to an earthquake at the installed location; a storage means for storing the CPU, programs and data; A second measuring device comprising a second sensor for measuring a physical quantity related to an earthquake at a certain point, and a terminal or server for recording and processing measurement data are connected via a network, and the first and first A measurement data correction method in a measurement system in which two measurement devices are respectively arranged on a structure to be measured,
Setting a transfer function relating the physical quantity in the first measuring device and the physical quantity in the second measuring device;
Calculating a time lag of the second measurement data in the second measurement device with respect to the first measurement data in the first measurement device using the transfer function;
And a time shift correction step of correcting the time of the second measurement data linearly according to the time of the second measurement data based on the time shift. The time lag correction step includes:
Extracting the end time of the earthquake-free state before the state change of the structure and the start time of the earthquake-free state after the state change of the structure based on the time of the state change of the structure,
8. The method of correcting measurement data according to claim 7, wherein the time lag is linearly added to the time of the second measurement data between these times. A first measuring device having a first sensor for measuring a physical quantity relating to an earthquake, a second measuring device having a second sensor for measuring a physical quantity relating to an earthquake, and a terminal for recording and processing measurement data And a server and a network connecting them,
A measurement system that causes the terminal or the server to execute the following steps.
a set a transfer function relating the physical quantity in the first measuring device and the physical quantity in the second measuring device b measured by the first acceleration measured by the first sensor and the second sensor C) receiving a second acceleration; c) calculating a displacement value based on the first acceleration and the transfer function and calculating a displacement value based on the second acceleration. The number of different bits is calculated by comparing each bit of the binary value of the displacement and the binary value of the displacement calculated based on the second acceleration. E Structure based on the calculated number of different bits Determining changes in the state of things The measurement system according to claim 9, further causing the terminal or the server to execute the following steps.
f Calculate a time lag of the second measurement data in the second measurement device with respect to the first measurement data in the first measurement device using the transfer function. g After the step f, the time lag. Based on the above, the time of the second measurement data is linearly corrected according to the time of the second measurement data The measurement system according to claim 10, wherein the terminal or the server executes the following steps.
In the step g, the end time of the earthquake-free state before the state change of the structure and the start time of the earthquake-free state after the state change of the structure are extracted based on the time of the state change of the structure,
The time shift between these times is linearly added to the time of the second measurement data.

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