Earthquake risk assessment device, earthquake risk assessment method, and program
The earthquake risk assessment device and method address the challenge of inaccurate seismic risk evaluation by calculating ground risk indices using Fourier spectral ratios and pre-trained models, facilitating efficient and precise risk assessment for buildings of varying heights.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- HIROSHIMA UNIVERSITY
- Filing Date
- 2025-06-12
- Publication Date
- 2026-06-05
AI Technical Summary
Existing methods for evaluating seismic risk and resistance of buildings fail to consider the type of ground on which they are built, leading to inaccurate assessments, especially for mid- or high-rise structures, and are time-consuming and expensive due to separate data collection for buildings and grounds.
An earthquake risk assessment device and method that calculates the Fourier spectral amplitude ratio of ground motions, determines the ground amplification factor, and uses a pre-trained model to estimate the ground risk index, incorporating ground-specific data for accurate seismic risk evaluation.
Enables easy and accurate assessment of earthquake risk by quantifying building and ground susceptibility, reducing the need for separate data collection and improving assessment accuracy for various building types.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to an earthquake risk assessment device, an earthquake risk assessment method, and a program for quantitatively evaluating the earthquake risk of buildings and ground.
Background Art
[0002] Conventionally, various methods have been developed for evaluating the earthquake risk, seismic resistance, etc. of buildings. In the method of Patent Document 1, the constant micro-vibration between a building and the ground is measured, and the seismic performance of the building is evaluated based on the natural period, resonance degree, and amplification factor calculated from the Fourier spectrum of the measured constant micro-vibration.
[0003] Also, in the method of Patent Document 2, the natural vibration frequency of a building and the natural vibration frequency of the ground are obtained, and the seismic resistance of the building is evaluated based on the difference between the obtained natural vibration frequency of the building and the natural vibration frequency of the ground.
Prior Art Documents
Patent Documents
[0004]
Patent Document 1
Patent Document 2
Summary of the Invention
Problems to be Solved by the Invention
[0005] In evaluating the seismic risk and seismic resistance of buildings, the risk of damage to a building from an earthquake varies depending on the type of ground on which it is built. However, in the evaluation method described in Patent Document 1, although measurement data of the ground is used in evaluating the vibration characteristics of the building, the natural frequency of the ground is not considered, and the building's susceptibility to resonance is not evaluated. Furthermore, the risk assessment of the ground itself is not performed. Therefore, it is difficult to perform an accurate assessment of the building's risk that takes into account the risks inherent in the ground using the method described in Patent Document 1. In addition, the method described in Patent Document 1 is a technology that applies to two-story houses and does not apply to mid- or high-rise buildings.
[0006] The method described in Patent Document 2 allows for the evaluation of a building's seismic resistance by considering the properties of the ground. Furthermore, Patent Document 2 states that ground-specific data should be obtained from geographic maps, prior research, etc. Therefore, if ground-specific data has not been obtained in advance, it is difficult to reflect the characteristics of the ground in the seismic risk assessment. In addition, obtaining data related to the evaluation of the building and data related to the evaluation of the ground separately is time-consuming and expensive, making it difficult to easily and accurately assess the seismic risk of a building. Moreover, the risk assessment of the ground itself has not been performed, making it difficult to accurately assess the risk of a building that takes into account the influence of the risks inherent in the ground using the method described in Patent Document 2.
[0007] This invention has been made in view of the above circumstances, and aims to provide an earthquake risk assessment device, an earthquake risk assessment method, and a program that can easily and accurately assess the risk of ground during earthquakes. [Means for solving the problem]
[0008] To achieve the above objective, the earthquake risk assessment device according to the first aspect of this invention is: From the ambient microtremor information of the ground being evaluated, the Fourier spectral amplitude ratio of the horizontal and vertical motions of the ground is calculated, and the ground amplification factor is calculated based on the Fourier spectral amplitude ratio. The system includes a ground risk calculation unit that calculates a ground risk index representing the susceptibility of the ground to damage from the peak frequency and peak value of the ground amplification factor.
[0009] Furthermore, the Fourier spectral amplitude ratio is calculated using the following formula:
number
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[0010] Furthermore, the ground amplification factor is estimated using a pre-trained model that takes the Fourier spectral amplitude ratio as input and the ground amplification factor as output. It would be acceptable to do so.
[0011] Furthermore, in the earthquake risk assessment method according to the second aspect of the present invention, From the ambient microtremor information of the ground being evaluated, the Fourier spectral amplitude ratio of the horizontal and vertical motions of the ground is calculated, and the ground amplification factor is calculated based on the Fourier spectral amplitude ratio. A ground risk index representing the susceptibility of the ground to damage is calculated from the peak frequency and peak value of the ground amplification factor.
[0012] Furthermore, the program relating to the third aspect of the present invention is Computers, From the ambient microtremor information of the ground being evaluated, the Fourier spectral amplitude ratio of the horizontal and vertical motions of the ground is calculated, and the ground amplification factor is calculated based on the Fourier spectral amplitude ratio. A ground risk calculation unit calculates a ground risk index representing the susceptibility of the ground to damage from the peak frequency and peak value of the ground amplification factor. To make it function as such. [Effects of the Invention]
[0013] According to the earthquake risk assessment device, earthquake risk assessment method, and program of the present invention, it is possible to easily and accurately assess the earthquake risk of the ground being assessed. [Brief explanation of the drawing]
[0014] [Figure 1] This is a functional block diagram of an earthquake risk assessment device according to an embodiment of the present invention. [Figure 2] This flowchart shows the flow of earthquake risk assessment according to the embodiment. [Figure 3] This is a flowchart showing the calculation process for the building resonance risk index. [Figure 4] This graph shows an example of the relationship between a building's natural frequency and the number of floors in the building. [Figure 5] This graph shows an example of the relationship between the natural frequency of the ground and the natural frequency of a building. [Figure 6] This is a flowchart showing the calculation process for ground risk indicators. [Figure 7] This figure shows an example of the relationship between MHVR, pseudo-ground amplification factor, and ground risk indicators. [Figure 8] This diagram shows an example of a comprehensive risk indicator divided into nine categories. [Figure 9] This diagram shows an example of how the overall risk indicator can be divided into five categories. [Figure 10] This graph shows an example of a building's vibration spectrum. [Figure 11] This figure shows the relationship between the MHVR, pseudo-ground amplification factor, and ground risk index of the building shown in Figure 10. [Figure 12] This graph shows an example of a vibration spectrum for a different building from Figure 10. [Figure 13] This figure shows the relationship between the MHVR, pseudo-ground amplification factor, and ground risk index of the building shown in Figure 12. [Modes for carrying out the invention]
[0015] The following describes an embodiment of the earthquake risk assessment device 1 according to the present invention, with reference to the figures. The earthquake risk assessment device 1 is a device for evaluating the earthquake risk of buildings and ground. As shown in the functional block diagram of Figure 1, the earthquake risk assessment device 1 according to this embodiment comprises a control unit 11, a storage unit 12, a display unit 13, and an input unit 14.
[0016] The control unit 11 consists of a CPU (Central Processing Unit), ROM (Read Only Memory), RAM (Random Access Memory), etc., and controls the operation of the earthquake risk assessment device 1. The control unit 11 also calculates the earthquake risk index for building B based on vibration information of building B and the ground G near building B, and performs an earthquake risk assessment. The control unit 11 realizes the various functions of the control unit 11 shown in Figure 1 by reading various operation programs and data stored in the ROM, memory unit 12, etc. of the control unit 11 into the RAM and operating the CPU, etc. As a result, the control unit 11 operates as a building vibration data acquisition unit 111, a ground vibration data acquisition unit 112, a building resonance risk calculation unit 113, a ground risk calculation unit 114, and a comprehensive risk assessment unit 115.
[0017] The building vibration data acquisition unit 111 acquires building vibration data, which is vibration information measured for building B. The acquired building vibration data consists of ambient tremor information, which is time-series data related to ambient tremors measured inside building B, and is information acquired for a first horizontal direction and a second horizontal direction that are orthogonal in the horizontal plane. The orientations of the first horizontal direction and the second horizontal direction are not particularly limited, but it is preferable to set the first horizontal direction to the NS (north-south) direction and the second horizontal direction to the EW (east-west) direction so that it is easy to compare with information from other buildings. In this embodiment, the first horizontal direction is the NS direction and the second horizontal direction is the EW direction.
[0018] Furthermore, in order to consider the degree of vibration amplification in the vertical direction of building B, the building vibration data will consist of vibration information measured on both the top and bottom floors of building B.
[0019] Furthermore, the building vibration data acquisition unit 111 may immediately acquire the output of the vibration pickup 22 connected to the earthquake risk assessment device 1, or it may acquire building vibration data that has been acquired in advance and stored in the storage unit 12 or an external server 21 connected via a network.
[0020] The ground vibration data acquisition unit 112 acquires ground vibration data, which is vibration information acquired for the ground G in the vicinity of building B. The acquired ground vibration data consists of ambient vibration information, which is time-series data related to ambient vibrations measured in the vicinity of building B, for example, at a point about 10 m away from building B. It is vibration information measured in the first horizontal direction and the second horizontal direction which are orthogonal in the horizontal plane, and in the vertical direction. The orientations of the first horizontal direction and the second horizontal direction are the same as the vibration measurement orientation of building B. In this embodiment, the first horizontal direction is set to the NS direction and the second horizontal direction is set to the EW direction. This makes it easy to compare vibration information of building B with that of other ground.
[0021] Furthermore, the ground vibration data acquisition unit 112 may immediately acquire the output of the vibration pickup 22 connected to the earthquake risk assessment device 1, or it may acquire ground vibration data that has been measured in advance and stored in the storage unit 12 or an external server 21 connected via a network.
[0022] The building resonance risk calculation unit 113 calculates a building resonance risk index R, which represents the resonance risk of building B, based on the building vibration data acquired by the building vibration data acquisition unit 111 and the ground vibration data acquired by the ground vibration data acquisition unit 112.
[0023] Specifically, the building resonance risk calculation unit 113 performs a Fourier transform on the building vibration data, which is time-series waveform data for each direction, to decompose it into a frequency spectrum, and determines the first natural frequency f of building B. 1x ,f 1yCalculate it. Also, the building resonance risk calculation unit 113 calculates the spectral amplitude ratio of the horizontal motion and the vertical motion of the ground G (hereinafter, also referred to as the horizontal motion / vertical motion spectral amplitude ratio or MHVR), and calculates the natural vibration frequency f of the ground from the calculated MHVR gMHVR Calculate it. Then, the first natural vibration frequency f of the building B 1x , f 1y And, based on the difference between the natural vibration frequency f of the ground gMHVR , calculate the building resonance risk index R. The detailed calculation method of the building resonance risk index R will be described later
[0024] Based on the ground vibration data acquired by the ground vibration data acquisition unit 112, the ground risk calculation unit 114 calculates the ground risk index K g As the vulnerability index. Specifically, the ground risk calculation unit 114 calculates the MHVR of the ground G, and calculates the ground amplification factor SAF from the calculated MHVR. Then, the vulnerability index calculated from the peak frequency f g And the peak value A g Is used as the ground risk index K g . The detailed calculation method of the ground risk index K g Will be described later
[0025] Based on the building resonance risk index R calculated by the building resonance risk calculation unit 113 and the ground risk index K g Calculated by the ground risk calculation unit 114, the comprehensive risk evaluation unit 115 evaluates the comprehensive risk representing the risk of the building considering the risk of the ground
[0026] The storage unit 12 is a non-volatile memory such as a hard disk or a flash memory, and stores a program for calculating the building resonance risk index R, the ground risk index K g Etc. from the building vibration data and the ground vibration data, and information such as various vibration data and the calculated risk indices
[0027] The display unit 13 is a display device provided in the earthquake risk assessment device 1, and is, for example, a liquid crystal panel. The display unit 13 displays various spectral data, risk indicators, etc., calculated by the control unit 11.
[0028] The input unit 14 is an input device for inputting parameter settings and other information for calculating various risk indicators. The input unit 14 is a keyboard, touch panel, mouse, etc., provided in the earthquake risk assessment device 1.
[0029] Next, we will explain the earthquake risk assessment method using the earthquake risk assessment device 1, referring to the flowchart in Figure 2.
[0030] (Vibration data acquisition process) As part of the vibration data acquisition process, the building vibration data acquisition unit 111 of the earthquake risk assessment device 1 acquires building vibration data, which is vibration information measured for building B, the building to be evaluated (step S1). The acquired building vibration data is time-series data relating to ambient tremors measured using the vibration pickup 22 on the top and bottom floors of building B. The building vibration data according to this embodiment is vibration data in the NS direction, which is the first horizontal direction orthogonal in the horizontal plane, and the EW direction, which is the second horizontal direction.
[0031] The building vibration data acquisition unit 111 according to this embodiment acquires building vibration data by reading building vibration data that has been measured in advance and stored in a server 21 connected to the earthquake risk assessment device 1 via a network. In order to perform processing to reduce the effects of noise, it is preferable that the acquired building vibration data is 10 minutes or longer in length.
[0032] Next, the ground vibration data acquisition unit 112 of the earthquake risk assessment device 1 acquires ground vibration data, which is vibration information measured for the ground G near building B (step S2). The acquired ground vibration data is time-series data relating to ambient tremors measured using a vibration pickup 22 at a point approximately 10 m away from building B. The ground vibration data according to this embodiment is vibration data in the first horizontal direction, the NS direction, the second horizontal direction, the EW direction, and the vertical direction, all of which are orthogonal in the horizontal plane.
[0033] The ground vibration data acquisition unit 112 according to this embodiment acquires ground vibration data by reading ground vibration data that has been measured in advance and stored in a server 21 connected to the earthquake risk assessment device 1 via a network. In order to perform processing to reduce the effects of noise, it is preferable that the acquired ground vibration data is 10 minutes or longer in length.
[0034] (Building resonance risk calculation process) Next, as part of the building resonance risk calculation process, the building resonance risk calculation unit 113 calculates the building resonance risk index R (step S3).
[0035] In detail, as shown in the flowchart of Figure 3, the building resonance risk calculation unit 113 extracts multiple data points for predetermined intervals from the building vibration data for the NS and EW directions on the top floor and the NS and EW directions on the bottom floor (step S11). The predetermined extraction interval should be set within a range where a significant frequency range including the building's natural frequency can be analyzed by spectral decomposition. For example, in this embodiment, the peak frequency of the Fourier spectrum used for analysis is in the range of 1.0 to 20.0 Hz, so the predetermined extraction interval is set to 20.48 seconds.
[0036] The number of sections to be extracted is not particularly limited, but for example, there can be 3 to 10 sections for each direction of building vibration data. The method of selecting the sections to be extracted is not particularly limited; methods such as extracting at predetermined time intervals or allowing the user to select sections with less noise can be used. By extracting multiple sections of predetermined length from sufficiently long building vibration data and performing the averaging process described later, the influence of noise can be reduced, and a highly reliable seismic risk assessment can be performed.
[0037] The building resonance risk calculation unit 113 performs a Fourier transform on each of the extracted building vibration data sections and calculates the frequency spectrum (step S12). The building resonance risk calculation unit 113 also smooths the calculated spectrum (step S13). In this embodiment, the calculation spectrum is smoothed by applying a 0.3 Hz Parzen window. The building resonance risk calculation unit 113 then averages the smoothed spectra for the NS and EW directions on the top floor and the NS and EW directions on the bottom floor (step S14). This gives the average spectrum for the NS and EW directions on the top floor and the NS and EW directions on the bottom floor.
[0038] The building resonance risk calculation unit 113 uses the average spectra of the NS and EW directions at the top floor and the NS and EW directions at the bottom floor, calculated in step S14, to calculate a spectrum (hereinafter referred to as the amplified spectrum) for each of the NS and EW directions by dividing the spectrum of the top floor by the spectrum of the bottom floor (step S15). This makes it possible to quantify the degree of vibration amplification related to building B.
[0039] The building resonance risk calculation unit 113 calculates the peak frequency of the amplified spectrum calculated in step S15 as the primary natural frequency f in the NS direction of building B. 1x , the first natural frequency f in the EW direction 1yThis is derived as (step S16). This allows for the accurate calculation of the natural frequencies of building B in the NS and EW directions, respectively, while reducing the influence of noise. In this embodiment, the first natural frequency is used as the natural frequency. This makes it possible to easily calculate the building resonance risk without using second natural frequencies or other frequencies whose degree of influence is difficult to evaluate.
[0040] Figure 4 is a graph showing an example of the first natural frequency f1 of a building calculated by the procedure described above. As shown in Figure 4, the relationship between the number of floors in a building and the natural frequency can be approximated by the building structure, and it can be seen that the vibration characteristics of a building can be represented by the natural frequency according to this embodiment.
[0041] Furthermore, the building resonance risk calculation unit 113 calculates the natural frequency f of the ground G. g The calculation is performed. Specifically, the building resonance risk calculation unit 113 extracts multiple data points for predetermined intervals from the ground vibration data of the ground G acquired in step S2 in the NS direction, EW direction, and vertical direction (step S17). The predetermined extraction intervals should be set within a range where a significant frequency range including the natural frequency of the ground can be analyzed by spectral decomposition. For example, in this embodiment, the peak frequency of the Fourier spectrum used for analysis is in the range of 1.0 to 20.0 Hz, so the predetermined extraction interval is set to 20.48 seconds.
[0042] The number of sections to be extracted is not particularly limited, but for example, there can be 3 to 10 sections for each direction of ground vibration data. The method of selecting the sections to be extracted is not particularly limited; methods such as extracting at predetermined time intervals or the user selecting sections with less noise can be used. Similar to building vibration data, by extracting multiple sections of predetermined length from sufficiently long ground vibration data and performing the averaging process described later, the influence of noise can be reduced, and a highly reliable seismic risk assessment can be performed.
[0043] The building resonance risk calculation unit 113 performs a Fourier transform on each of the ground vibration data for the extracted section and calculates the frequency spectrum (step S18). The building resonance risk calculation unit 113 then smooths the calculated spectrum (step S19). In this embodiment, the calculated spectrum is smoothed by applying a 0.3 Hz Parzen window. The building resonance risk calculation unit 113 then averages the smoothed spectra for the NS direction, EW direction, and vertical direction of the ground G (step S20). This gives the average spectrum of the ground G in the NS direction, EW direction, and vertical direction.
[0044] The building resonance risk calculation unit 113 calculates the horizontal-to-vertical Fourier spectrum amplitude ratio (MHVR) of the ground G using the average spectra of the ground G in the NS direction (first horizontal direction), EW direction (second horizontal direction), and vertical direction calculated in step S20 (step S21). The MHVR is calculated by the following equation (1).
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[0045] The building resonance risk calculation unit 113 uses the peak frequency of MHVR calculated in step S21 as the primary natural frequency f of the ground G. gMHVR This is derived (step S22). This allows the natural frequency of the ground G to be calculated accurately while reducing the influence of noise.
[0046] Next, the building resonance risk calculation unit 113 calculates the building resonance risk index R (step S23). Specifically, for each of the NS and EW directions, the building resonance risk calculation unit 113 calculates the resonance risk index R, which represents the risk due to resonance of building B, based on the magnitude of the difference between the natural frequency of building B and the natural frequency of the ground G. x(NS direction),R y Calculate (EW direction).
[0047] Figure 5 shows the natural frequency f1 of the building and the natural frequency f of the ground. gMHVR This figure shows an example of the relationship between the natural frequency f1 of the building and the natural frequency f of the ground. As shown in Figure 5, the natural frequency f1 of the building and the natural frequency f of the ground gMHVR When these two conditions coincide, resonance is likely to occur, and the natural frequency f1 of the building and the natural frequency f of the ground are the same. gMHVR The closer the two points are, the higher the risk of resonance.
[0048] The building resonance risk calculation unit 113 calculates the resonance risk index R using the following equations (2) and (3). x ,R y Perform the calculation.
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[0049] Furthermore, the building resonance risk calculation unit 113 calculates the resonance risk index R for each direction using the following equation (4): x ,R y From this, we calculate the building resonance risk index R, which represents the risk due to resonance in building B.
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[0050] As shown in equations (2) and (3) above, the closer the natural frequency of building B is to the natural frequency of ground G, the larger the value of the building resonance risk index R, and the more likely it is to resonate. Also, the lower the natural frequency of building B, such as in a high-rise building, the larger the value of the building resonance risk index R, and the more likely it is to resonate. The earthquake risk assessment device 1 according to this embodiment quantitatively evaluates the earthquake risk of a building using the building resonance risk index R, so it is possible to easily and accurately evaluate the risk of a building during an earthquake.
[0051] (Ground risk calculation process) Next, as part of the ground risk calculation process, the ground risk calculation unit 114 calculates the ground risk index K g The susceptibility index to disaster is calculated (Step S4).
[0052] In detail, as shown in the flowchart of Figure 6, the ground risk calculation unit 114 calculates the MHVR of the ground G (step S31). The MHVR calculated in step S21 described above may be used.
[0053] The ground risk calculation unit 114 calculates the ground amplification factor SAF from the MHVR calculated in step S31 (step S32). As a method for calculating the ground amplification factor SAF, for example, a method can be used that uses a trained model, which is machine-learned using known MHVR and ground amplification factor SAF data, and takes MHVR as input and outputs the ground amplification factor SAF (D. Pan, H. Miura et al., “Deep‐Neural‐Network‐Based Estimation of Site Amplification Factor from Microtremor H / V Spectral Ratio”, Bulletin of the Seismological Society of America, Volume 112, Number 3, p.1630-1646, 2022). This makes it possible to derive a pseudo-ground amplification factor pSAF, which is an estimated value of the ground amplification factor SAF, from the MHVR calculated in step S31.
[0054] In this embodiment, the pseudo-ground amplification factor pSAF estimated using a trained model is used as the ground amplification factor SAF. This makes it possible to easily calculate the ground amplification factor SAF from MHVR, which is also used in the calculation of the building resonance risk index R, without having to separately acquire data on the vibration characteristics of the ground.
[0055] The ground risk calculation unit 114 calculates the peak frequency f of the ground amplification factor SAF calculated in step S32. gSAFand peak value A gSAF From ground risk index K g The susceptibility index to disaster is calculated (step S33). Ground risk index K g This is calculated by the following formula (5).
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[0056] Figure 7 shows MHVR, pseudo-ground amplification factor pSAF, and ground risk index K. g This figure shows an example of the relationship. In this example, the peak frequency f of the pseudo-ground amplification factor pSAF estimated based on MHVR. gSAF =4.2Hz and peak value A gSAF =12.0, the ground risk index K g =34.1 has been calculated.
[0057] (Comprehensive Risk Assessment Process) Next, in the comprehensive risk assessment process, the comprehensive risk assessment unit 115 uses the building resonance risk index R calculated in the building resonance risk calculation process and the ground risk index K calculated in the ground risk calculation process. g Based on this, a comprehensive risk assessment is conducted (Step S5).
[0058] The overall risk index, which takes into account the resonance risk of building B and the risk of ground G, is, for example, as shown in Figure 8, the magnitude of the building resonance risk index R and the ground risk index K. g It is evaluated by multiple categories based on the combination with its size.
[0059] Specifically, the resonance risk of building B is divided into three categories based on the value of the building resonance risk index R. Furthermore, the ground risk is assessed using the ground risk index K. g Based on the values, it is divided into three categories. Based on these categories, the larger the value of the building resonance risk index R, and the higher the ground risk index K g The higher the value, the greater the overall risk. The number of categories for the overall risk indicator is not limited to the nine levels shown in Figure 8; for example, there may be five levels as shown in Figure 9.
[0060] The control unit 11 stores the overall risk index evaluated in step S5 in the storage unit 12 and displays it on the display unit 13 (step S6), thus ending the earthquake risk assessment. Along with the overall risk index, the control unit 11 also stores the building resonance risk index R and the ground risk index K. g The data may be stored in the memory unit 12 and displayed on the display unit 13.
[0061] As described above, the earthquake risk assessment device and earthquake risk assessment method according to this embodiment calculate the resonance risk of the building and the ground risk from vibration data of the building to be assessed and the ground near the building, and assess the earthquake risk of the building based on these. Therefore, the earthquake risk of the building, taking into account the characteristics of the ground, can be easily and accurately assessed without measuring or acquiring other vibration information.
[0062] (Example of evaluation) An example of building seismic risk assessment using the seismic risk assessment method according to the above embodiment will be described. Figure 10 is a graph showing the measurement results of ambient microtremors for a building B1. Building B1 is a steel-reinforced concrete (SRC) building with 10 floors (1st to 10th floors above ground). As shown in Figure 10, the primary natural frequency f1 of building B1 is f 1x =1.37Hz, f 1y = 1.32 Hz. Also, the primary natural frequency f of the ground G1 near building B1. gMHVR is f gMHVR =3.76Hz. The primary natural frequency f1 of building B1 and the primary natural frequency f of ground G1 gMHVR Therefore, the building resonance risk index is R x =1.07, R y The calculation is performed as =1.04, and the building resonance risk index R for building B1 is calculated to be R=1.07.
[0063] Furthermore, the MHVR of ground G1 and the pseudo-ground amplification factor pSAF estimated using the trained model from the MHVR are as shown in Figure 11, with a peak frequency f gSAF The frequency is 3.9Hz, peak value A gSAFThe value was 12.5. Furthermore, the ground risk index K is calculated based on the estimated pseudo-ground amplification factor pSAF. g is, K g The result was 40.1.
[0064] Figure 12 is a graph showing the measurement results of ambient vibrations in building B2, which is different from building B1. Building B2 is a steel-reinforced concrete (SRC) building with 6 floors (1 basement floor to 6 above ground). As shown in Figure 12, the primary natural frequency f1 of building B2 is f 1x =2.30Hz, f 1y =3.17Hz. Also, the primary natural frequency f of the ground G2 near building B2. gMHVR is f gMHVR = 1.71 Hz. The primary natural frequency f1 of building B2 and the primary natural frequency f of ground G2 gMHVR Therefore, the building resonance risk indicators for the first horizontal direction (NS direction) and the second horizontal direction (EW direction) are R x =3.29, R y The calculation is 1.49, and the building resonance risk index R for building B2 is calculated to be R=3.29.
[0065] Furthermore, the MHVR of ground G2 and the pseudo-ground amplification factor pSAF estimated using the trained model from the MHVR are as shown in Figure 13, with a peak frequency f gSAF The frequency is 1.7Hz, peak value A gSAF The value was 12.5. Furthermore, the ground risk index K is calculated based on the estimated pseudo-ground amplification factor pSAF. g is, K g The result was 91.9.
[0066] Building resonance risk index R and ground risk index K for buildings B1 and B2 mentioned above. gBased on this, if we evaluate the overall risk index of buildings B1 and B2 on a 9-point scale according to the table in Figure 8, the overall risk index of building B1 can be evaluated as B, and the overall risk index of building B2 can be evaluated as B. As described above, by calculating the resonance risk of the buildings and the ground risk from the vibration data of the buildings B1 and B2 and the ground G1 and G2 near the buildings, the seismic risk of the buildings, taking into account the characteristics of the ground, can be easily and accurately evaluated by combining these.
[0067] In the above embodiment, the building resonance risk index R and the ground risk index K g The system is designed to calculate a comprehensive risk index representing the seismic risk of a building by combining these factors and considering the characteristics of the ground, but it is not limited to this. The seismic risk assessment device 1 uses building resonance risk R, which represents the seismic risk of the building, and ground risk index K, which represents the seismic risk of the ground. g It is also possible to evaluate these factors independently. This makes it easy and accurate to compare and evaluate the seismic risk of multiple buildings, or the seismic risk of the ground at multiple locations.
[0068] Furthermore, the earthquake risk assessment according to the above embodiment can be implemented using a standard computer system. For example, by distributing a computer program for performing the earthquake risk assessment according to the above embodiment via a network such as the Internet, and installing the computer program on a computer, the computer device can be made to function as the earthquake risk assessment device described above. [Industrial applicability]
[0069] This invention is suitable for evaluating the seismic risk of ground and buildings. [Explanation of Symbols]
[0070] 1 Earthquake risk assessment device, 11 Control unit, 111 Building vibration data acquisition unit, 112 Ground vibration data acquisition unit, 113 Building resonance risk calculation unit, 114 Ground risk calculation unit, 115 Comprehensive risk assessment unit, 12 Storage unit, 13 Display unit, 14 Input unit, 21 Server, 22 Vibration pickup
Claims
1. From the ambient microtremor information of the ground being evaluated, the Fourier spectral amplitude ratio of the horizontal and vertical motions of the ground is calculated, and the ground amplification factor is calculated based on the Fourier spectral amplitude ratio. The system includes a ground risk calculation unit that calculates a ground risk index representing the susceptibility of the ground to damage from the peak frequency and peak value of the ground amplification factor. An earthquake risk assessment device characterized by the following features.
2. The Fourier spectral amplitude ratio is calculated using the following formula: [Math 1] The aforementioned ground risk index is calculated using the following formula: [Math 2] The earthquake risk assessment device according to feature 1.
3. The aforementioned ground amplification factor is estimated using a pre-trained model that takes the Fourier spectral amplitude ratio as input and the ground amplification factor as output. The earthquake risk assessment device according to feature 2.
4. From the ambient microtremor information of the ground being evaluated, the Fourier spectral amplitude ratio of the horizontal and vertical motions of the ground is calculated, and the ground amplification factor is calculated based on the Fourier spectral amplitude ratio. A ground risk index representing the susceptibility of the ground to damage is calculated from the peak frequency and peak value of the ground amplification factor. A method for evaluating earthquake risk, characterized by the following features.
5. Computers, From the ambient microtremor information of the ground being evaluated, the Fourier spectral amplitude ratio of the horizontal and vertical motions of the ground is calculated, and the ground amplification factor is calculated based on the Fourier spectral amplitude ratio. A ground risk calculation unit calculates a ground risk index representing the susceptibility of the ground to damage from the peak frequency and peak value of the ground amplification factor. A program that makes it function as such.