Earthquake risk assessment device, earthquake risk assessment method, and program

Abstract

Provided are a seismic risk assessment device, a seismic risk assessment method, and a program that can easily and accurately evaluate the seismic risks of buildings and the ground. 【Solution means】The seismic risk assessment device 1 calculates the natural frequencies in the first horizontal direction and the second horizontal direction orthogonal thereto from the ambient vibration information of the top and bottom floors of the building, calculates the Fourier spectrum amplitude ratio of the horizontal motion and the vertical motion of the ground from the ambient vibration information of the ground near the building, calculates the ground amplification factor based on the Fourier spectrum amplitude ratio, calculates the natural frequency of the ground from the ground amplification factor, and calculates a building resonance risk index based on the magnitude of the difference between the natural frequencies of the building and the ground. A building resonance risk calculation unit 113, a ground risk calculation unit 114 that calculates a ground risk index from the peak frequency and peak value of the ground amplification factor, and a comprehensive risk assessment unit 115 that calculates a comprehensive risk index representing the seismic risk of the building based on the building resonance risk index and the ground risk index.

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 for evaluating the earthquake risk, seismic resistance, etc. of buildings have been developed. 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 acquired, and the seismic resistance of the building is evaluated based on the difference between the acquired 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 the evaluation of the seismic risk, seismic resistance, etc. of a building, the damage risk of the building due to an earthquake varies depending on the type of ground on which the building is constructed. However, in the evaluation method of Patent Document 1, although the measured data of the ground is used in the evaluation of the vibration characteristics of the building, the natural frequency of the ground is not considered, and the susceptibility of the building to resonance is not evaluated. In addition, the risk assessment of the ground itself is not performed. Therefore, it is difficult to accurately evaluate the risk of a building considering the influence of the risk of the ground by the method of Patent Document 1. Further, the method of Patent Document 1 is a technology targeted at two-story houses and does not target mid- and high-rise buildings.

[0006] In the method of Patent Document 2, it is stated that the seismic resistance of a building may be evaluated considering the properties of the ground. Also, in Patent Document 2, the data specific to the ground is to be obtained from geographical maps, previous studies, etc. Therefore, when there is no pre-acquired data specific to the ground, it is difficult to reflect the characteristics of the ground in the seismic risk assessment. Also, it takes a lot of effort and cost to separately acquire the data related to the evaluation of the building and the data related to the evaluation of the ground, and it is difficult to easily and accurately evaluate the seismic risk of the building. In addition, the risk assessment of the ground itself is not performed, and it is difficult to accurately evaluate the risk of a building considering the influence of the risk of the ground by the method of Patent Document 2.

[0007] The present invention has been made in view of the above circumstances, and an object thereof is to provide a seismic risk assessment device, a seismic risk assessment method, and a program that can easily and accurately evaluate the seismic risks of a building and the ground.

Means for Solving the Problems

[0008] To achieve the above object, a seismic risk assessment device according to a first aspect of the present invention calculates a first natural frequency in the horizontal direction and a second natural frequency in a second horizontal direction orthogonal to the first horizontal direction from the ambient vibration information of the top floor and the bottom floor of the building to be evaluated, From the ambient vibration information of the ground near the building, calculate the Fourier spectrum amplitude ratio of the horizontal vibration and vertical vibration of the ground, and calculate the natural vibration frequency of the ground from the Fourier spectrum amplitude ratio. It is provided with a building resonance risk calculation unit that calculates a building resonance risk index representing the risk due to resonance of the building based on the magnitude of the difference between the natural vibration frequency of the building and the natural vibration frequency of the ground. The building resonance risk index is calculated using the following formula.

Equation

[0009] Also, the Fourier spectrum amplitude ratio is calculated using the following formula.

Equation

[0014] Also, in the earthquake risk assessment method according to the 2 viewpoint of the present invention, From the ambient vibration information of the top floor and the bottom floor of the building to be evaluated, calculate the natural vibration frequency in the first horizontal direction and the natural vibration frequency in the second horizontal direction orthogonal to the first horizontal direction. From the ambient vibration information of the ground near the building, calculate the Fourier spectrum amplitude ratio of the horizontal vibration and vertical vibration of the ground, and calculate the natural vibration frequency of the ground from the Fourier spectrum amplitude ratio. Based on the magnitude of the difference between the natural vibration frequency of the building and the natural vibration frequency of the ground, a building resonance risk index representing the risk due to resonance of the building , it is used by the following formula is calculated .

Equation

[0015] Also, the program according to the 3 viewpoint of the present invention is to cause a computer to From the constant minute vibration information of the top floor and the bottom floor of the building to be evaluated, calculate the first horizontal natural vibration frequency and the second horizontal natural vibration frequency orthogonal to the first horizontal direction. From the constant minute vibration information of the ground near the building, calculate the Fourier spectrum amplitude ratio of the horizontal motion and the vertical motion of the ground, and calculate the natural vibration frequency of the ground from the Fourier spectrum amplitude ratio. Based on the magnitude of the difference between the natural vibration frequency of the building and the natural vibration frequency of the ground, a building resonance risk index representing the risk due to the resonance of the building , it is used by the following formula A building resonance risk calculation unit that calculates [Number] Function as. [Advantages of the Invention]

[0016] 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 risks of the building and the ground during an earthquake for the object to be evaluated. [Brief Description of the Drawings]

[0017]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Figure 8

Figure 9

Figure 10

Figure 11

Figure 12

Figure 13

Embodiments for Carrying Out the Invention

[0018] Hereinafter, with reference to the drawings, the seismic risk assessment device 1 according to the embodiment of the present invention will be described. The seismic risk assessment device 1 is a device for assessing the seismic risk of a building and the ground. As shown in the functional block diagram of FIG. 1, the seismic risk assessment device 1 according to the present embodiment includes a control unit 11, a storage unit 12, a display unit 13, and an input unit 14.

[0019] The control unit 11 is composed of a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and controls the operation of the seismic risk assessment device 1. Further, the control unit 11 calculates the risk index of the building B during an earthquake based on the vibration information of the building B to be evaluated and the ground G near the building B, and performs a seismic risk assessment. The control unit 11 reads various operation programs and data stored in the ROM of the control unit 11, the storage unit 12, etc. into the RAM and operates the CPU, etc., thereby realizing each function of the control unit 11 shown in FIG. 1. 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 evaluation unit 115.

[0020] The building vibration data acquisition unit 111 acquires building vibration data, which is vibration information measured for the building B. The acquired building vibration data is the ambient vibration information consisting of time-series data related to the ambient vibration measured inside the building B, and is the information acquired for each of the first horizontal direction and the second horizontal direction orthogonal to each other in the horizontal plane. The azimuths of the first horizontal direction and the second horizontal direction are not particularly limited, but in order to facilitate comparison with the information of other buildings, it is preferable to set the first horizontal direction as the NS (north-south) direction and the second horizontal direction as the EW (east-west) direction. In the present embodiment, the first horizontal direction is the NS direction and the second horizontal direction is the EW direction.

[0021] Also, in order to consider the amplitude increase rate of the vibration in the height direction of the building B, the building vibration data is set to be the vibration information measured on the top floor and the bottom floor of the building B, respectively.

[0022] Also, the building vibration data acquisition unit 111 may immediately acquire the output of the vibration pickup 22 connected to the seismic risk assessment device 1, or may acquire the 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.

[0023] The ground vibration data acquisition unit 112 acquires ground vibration data, which is vibration information acquired for the ground G near the building B. The acquired ground vibration data is the ambient vibration information consisting of time-series data related to the ambient vibration measured at a location near the building B, for example, about 10 m away from the building B, and is the vibration information measured for each of the first horizontal direction and the second horizontal direction orthogonal to each other in the horizontal plane and the vertical (up and down) direction. The azimuths of the first horizontal direction and the second horizontal direction are the same as the vibration measurement azimuths of the building B, and in the present embodiment, the first horizontal direction is set as the NS direction and the second horizontal direction is set as the EW direction. Thereby, comparison with the vibration information of the building B and other ground can be easily performed.

[0024] Alternatively, 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 may acquire the 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, etc.

[0025] 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, the building resonance risk calculation unit 113 calculates a building resonance risk index R representing the resonance risk of the building B.

[0026] Specifically, the building resonance risk calculation unit 113 performs Fourier transform on the building vibration data, which is time-series waveform data for each direction, to perform frequency spectrum decomposition, and calculates the first natural frequency f 1x , f 1y of the building B. Further, 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 frequency f gMHVR of the ground from the calculated MHVR. Then, based on the difference between the first natural frequency f 1x , f 1y of the building B and the natural frequency f gMHVR of the ground, the building resonance risk index R is calculated. The detailed calculation method of the building resonance risk index R will be described later.

[0027] Based on the ground vibration data acquired by the ground vibration data acquisition unit 112, the ground risk calculation unit 114 calculates a disaster susceptibility index as the ground risk index K g . 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 disaster susceptibility index calculated from the peak frequency f g and the peak value A g of the ground amplification factor SAF is taken as the ground risk index K g . The detailed calculation method of the ground risk index K g will be described later.

[0028] The comprehensive risk assessment unit 115 uses the building resonance risk index R calculated by the building resonance risk calculation unit 113 and the ground risk index K calculated by the ground risk calculation unit 114 g to evaluate the comprehensive risk representing the risk of the building considering the risk of the ground.

[0029] The storage unit 12 is a non-volatile memory such as a hard disk or a flash memory, and stores programs for calculating the building resonance risk index R, the ground risk index K, etc. from the building vibration data and the ground vibration data, various vibration data, and information such as the calculated risk indices. g

[0030] The display unit 13 is a display device provided in the seismic risk assessment device 1, such as a liquid crystal panel. The display unit 13 displays various spectrum data, risk indices, etc. calculated by the control unit 11.

[0031] The input unit 14 is an input device for inputting setting values of parameters for calculating various risk indices. The input unit 14 is a keyboard, a touch panel, a mouse, etc. provided in the seismic risk assessment device 1.

[0032] Subsequently, with reference to the flowchart of FIG. 2, a seismic risk assessment method using the seismic risk assessment device 1 will be described.

[0033] (Vibration data acquisition step) In the vibration data acquisition step, the building vibration data acquisition unit 111 of the seismic risk assessment device 1 acquires building vibration data, which is vibration information measured for the building B to be evaluated (step S1). The acquired building vibration data is time-series data related to the ambient vibration measured using the vibration pick-up 22 at the top floor and the bottom floor of the building B. The building vibration data according to the present 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.

[0034] ​The building vibration data acquisition unit 111 according to the present embodiment acquires building vibration data by reading the building vibration data that has been measured in advance and stored in the server 21 connected to the seismic risk assessment device 1 via a network. In order to perform processing for reducing the influence of noise, the acquired building vibration data is preferably data having a length of 10 minutes or more.

[0035] Subsequently, the ground vibration data acquisition unit 112 of the seismic risk assessment device 1 acquires ground vibration data, which is vibration information measured for the ground G near the building B (step S2). The acquired ground vibration data is time-series data related to microtremors constantly measured using the vibration pickup 22 at a point about 10 m away from the building B. The ground vibration data according to the present embodiment is vibration data in the NS direction, which is the first horizontal direction orthogonal in the horizontal plane, the EW direction, which is the second horizontal direction, and the vertical direction.

[0036] The ground vibration data acquisition unit 112 according to the present embodiment acquires ground vibration data by reading the ground vibration data that has been measured in advance and stored in the server 21 connected to the seismic risk assessment device 1 via a network. In order to perform processing for reducing the influence of noise, the acquired ground vibration data is preferably data having a length of 10 minutes or more.

[0037] (Building resonance risk calculation step) Subsequently, as a building resonance risk calculation step, the building resonance risk calculation unit 113 calculates a building resonance risk index R (step S3).

[0038] Specifically, as shown in the flowchart of FIG. 3, the building resonance risk calculation unit 113 extracts a plurality of data within a predetermined section from the building vibration data in the NS direction and the EW direction on the top floor and the building vibration data in the NS direction and the EW direction on the bottom floor (step S11). The predetermined extraction section may be set within a range that can analyze a significant frequency range including the natural vibration frequency of the building by spectral decomposition. For example, in the present embodiment, since the peak frequency of the Fourier spectrum used for analysis is in the range of 1.0 to 20.0 Hz, the predetermined extraction section is set to 20.48 seconds.

[0039] The number of extraction sections is not particularly limited. For example, for the building vibration data in each direction, there are 3 to 10 sections respectively. The method for selecting the extraction section is not particularly limited, and methods such as extracting at a predetermined time interval, or the user selecting and extracting a section with less noise can be used. By extracting a plurality of extraction sections of a predetermined length from the building vibration data of sufficient length and performing the averaging process described below, the influence of noise can be reduced and a highly reliable earthquake risk assessment can be performed.

[0040] The building resonance risk calculation unit 113 performs Fourier transform on the building vibration data for each of the extracted sections to calculate the frequency spectrum (step S12). Further, the building resonance risk calculation unit 113 smoothes the calculated spectrum (step S13). In the present embodiment, smoothing is performed by applying a Parzen window of 0.3 Hz to the calculated spectrum. Further, the building resonance risk calculation unit 113 averages the smoothed spectra for the NS direction and the EW direction on the top floor and the NS direction and the EW direction on the bottom floor respectively (step S14). As a result, the average spectra in the NS direction and the EW direction on the top floor and the NS direction and the EW direction on the bottom floor are obtained.

[0041] The building resonance risk calculation unit 113 uses the average spectra in the NS direction and EW direction on the top floor and the NS direction and EW direction on the bottom floor calculated in step S14 to calculate, for each of the NS direction and EW direction, a spectrum obtained by dividing the spectrum on the top floor by the spectrum on the bottom floor (hereinafter referred to as the amplification spectrum) (step S15). Thereby, the degree of amplification of the vibration related to the building B can be quantified.

[0042] The building resonance risk calculation unit 113 sets the peak frequency of the amplification spectrum calculated in step S15 as the first natural vibration frequency f 1x in the NS direction of the building B and the first natural vibration frequency f 1y in the EW direction (step S16). Thereby, the natural vibration frequencies in the NS direction and EW direction of the building B to be analyzed can be accurately calculated while reducing the influence of noise. In this embodiment, the first natural vibration frequency is used as the natural vibration frequency. Thereby, it is possible to easily calculate the building resonance risk without using the second natural vibration frequency or the like whose degree of influence is difficult to evaluate.

[0043] FIG. 4 is a graph showing an example of the first natural vibration frequency f1 of the building calculated by the above-described procedure. As shown in FIG. 4, the relationship between the building floor number and the natural vibration frequency can be approximated according to the building structure, and it can be seen that the vibration characteristics of the building can be represented by the natural vibration frequency according to this embodiment.

[0044] In addition, the building resonance risk calculation unit 113 calculates the natural vibration frequency f g of the ground G. Specifically, the building resonance risk calculation unit 113 cuts out a plurality of pieces of data in a predetermined section from the ground vibration data in the NS direction, EW direction, and vertical direction of the ground G acquired in step S2 (step S17). The predetermined cut-out section may be set within a range that can analyze a significant frequency range including the natural vibration frequency of the ground by spectrum decomposition. For example, in this embodiment, since the peak frequency of the Fourier spectrum used in the analysis is in the range of 1.0 to 20.0 Hz, the predetermined cut-out section is set to 20.48 seconds.

[0045] The number of cut-out sections is not particularly limited, but may be, for example, 3 to 10 sections for each direction of ground vibration data. The method for selecting the cut-out sections is not particularly limited, and it may be possible to use a method of cutting out sections at predetermined time intervals, or a method in which the user selects and cuts out sections with little noise. As with the building vibration data, by cutting out multiple cut-out sections of a predetermined length from ground vibration data of a sufficient length and performing the averaging process described below, it is possible to reduce the influence of noise and perform a highly reliable earthquake risk assessment.

[0046] The building resonance risk calculation unit 113 performs a Fourier transform on each piece of ground vibration data in the extracted section to calculate a frequency spectrum (step S18). The building resonance risk calculation unit 113 also smooths the calculated spectrum (step S19). In this embodiment, smoothing is performed by applying a Parzen window of 0.3 Hz to the calculated spectrum. The building resonance risk calculation unit 113 also averages the smoothed spectra for each of the NS and EW directions and the up-down direction of the ground G (step S20). This allows the average spectra for the NS and EW directions and the up-down direction of the ground G to be obtained.

[0047] The building resonance risk calculation unit 113 calculates the horizontal motion / vertical motion Fourier spectrum amplitude ratio (MHVR) of the ground G using the average spectra of the NS direction (first horizontal direction), EW direction (second horizontal direction), and vertical direction of the ground G calculated in step S20 (step S21). The MHVR is calculated using the following equation (1).

number

[0048] The building resonance risk calculation unit 113 derives the peak frequency of the MHVR calculated in step S21 as the fundamental natural frequency f of the ground G (step S22). Thereby, the natural frequency of the ground G can be accurately calculated while reducing the influence of noise. gMHVR Subsequently, the building resonance risk calculation unit 113 calculates a building resonance risk index R (step S23). Specifically, for each of the NS direction and the EW direction, the building resonance risk calculation unit 113 calculates a resonance risk index R

[0049] representing the risk due to the resonance of the building B based on the magnitude of the difference between the natural frequency of the building B and the natural frequency of the ground G. x (NS direction), R y (EW direction).

[0050] FIG. 5 is a diagram showing an example of the relationship between the natural frequency f1 of the building and the natural frequency f of the ground. As shown in FIG. 5, when the natural frequency f1 of the building coincides with the natural frequency f of the ground, resonance is likely to occur, and the closer the natural frequency f1 of the building is to the natural frequency f of the ground, the higher the resonance risk. gMHVR As shown in FIG. 5, when the natural frequency f1 of the building coincides with the natural frequency f of the ground, resonance is likely to occur, and the closer the natural frequency f1 of the building is to the natural frequency f of the ground, the higher the resonance risk. gMHVR As shown in FIG. 5, when the natural frequency f1 of the building coincides with the natural frequency f of the ground, resonance is likely to occur, and the closer the natural frequency f1 of the building is to the natural frequency f of the ground, the higher the resonance risk. gMHVR As shown in FIG. 5, when the natural frequency f1 of the building coincides with the natural frequency f of the ground, resonance is likely to occur, and the closer the natural frequency f1 of the building is to the natural frequency f of the ground, the higher the resonance risk.

[0051] The building resonance risk calculation unit 113 calculates the resonance risk index R x , R y by the following equations (2) and (3).

Equation

[0052] Furthermore, the building resonance risk calculation unit 113 calculates a building resonance risk index R representing the risk due to the resonance of the building B from the resonance risk indices R x , R y for each direction by the following equation (4).

Equation

[0053] As shown in the above formulas (2) and (3), the closer the natural frequency of the building B is to the natural frequency of the ground G, the larger the value of the building resonance risk index R, and it can be evaluated that resonance is likely to occur. Also, like a high-rise building, the lower the natural frequency of the building B, the larger the value of the building resonance risk index R, and it can be evaluated that resonance is likely to occur. Since the earthquake risk assessment device 1 according to the present embodiment quantitatively evaluates the earthquake risk of a building by the building resonance risk index R in this way, the risk of the building during an earthquake can be easily and accurately evaluated.

[0054] (Ground risk calculation step) Subsequently, as the ground risk calculation step, the ground risk calculation unit 114 calculates the disaster susceptibility index as the ground risk index K g (step S4).

[0055] Specifically, as shown in the flowchart of FIG. 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.

[0056] 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 using a trained model that takes the MHVR as input and outputs the ground amplification factor SAF, which is machine-learned using known data of the MHVR and 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) can be used. Thereby, the pseudo ground amplification factor pSAF, which is an estimated value of the ground amplification factor SAF, can be derived from the MHVR calculated in step S31.

[0057] In the present embodiment, the pseudo ground amplification factor pSAF estimated using the trained model is used as the ground amplification factor SAF. Thereby, it becomes possible to easily calculate the ground amplification factor SAF from the MHVR, which is also used for calculating the building resonance risk index R, without separately acquiring data regarding the vibration characteristics of the ground.

[0058] The ground risk calculation unit 114 calculates the peak frequency f gSAF and the peak value A gSAF of the ground amplification factor SAF calculated in step S32 to calculate the disaster susceptibility index as the ground risk index K g (step S33). The ground risk index K g is calculated by the following formula (5).

Equation

[0059] Figure 7 shows the MHVR, the pseudo ground amplification factor pSAF, and the ground risk index K gIt is a diagram showing an example of the relationship. In this example, the peak frequency f of the pseudo ground amplification factor pSAF estimated based on MHVR gSAF = 4.2 Hz and the peak value A gSAF = 12.0, the ground risk index K g = 34.1 has been calculated.

[0060] (Comprehensive Risk Assessment Process) Subsequently, as the comprehensive risk assessment process, the comprehensive risk assessment unit 115 performs a comprehensive risk assessment based on the building resonance risk index R calculated in the building resonance risk calculation process and the ground risk index K g calculated in the ground risk calculation process (step S5).

[0061] The comprehensive risk index considering the resonance risk of building B and the risk of ground G is evaluated by a plurality of categories based on, for example, the combination of the magnitude of the building resonance risk index R and the magnitude of the ground risk index K g as shown in, for example, FIG. 8.

[0062] Specifically, the resonance risk of building B is divided into three categories based on the value of the building resonance risk index R. Also, the risk of the ground is divided into three categories based on the value of the ground risk index K g Based on these categories, the greater the value of the building resonance risk index R and the greater the value of the ground risk index K g the greater the comprehensive risk is evaluated. The number of categories of the comprehensive risk index is not limited to the nine levels shown in FIG. 8, and may be, for example, five levels as shown in FIG. 9.

[0063] The control unit 11 stores the comprehensive risk index evaluated in step S5 in the storage unit 12 and displays it on the display unit 13 (step S6), and ends the seismic risk assessment. The control unit 11 may store the building resonance risk index R and the ground risk index K g in the storage unit 12 together with the comprehensive risk index and display them on the display unit 13.

[0064] As described above, according to the seismic risk assessment device and the seismic risk assessment method according to the present embodiment, the resonance risk and the ground risk of the building are calculated from the vibration data of the building to be evaluated and the ground near the building, and based on these, the seismic risk of the building is evaluated. Therefore, without measuring and acquiring other vibration information, etc., the seismic risk of the building considering the characteristics of the ground can be easily and accurately evaluated.

[0065] (Evaluation Example) An example of the seismic risk assessment of a building using the seismic risk assessment method according to the above embodiment will be described. FIG. 10 is a graph showing the measurement results of the ambient vibration of a certain building B1. Building B1 is a building with a steel frame reinforced concrete structure (SRC structure) and 10 floors (from the 1st floor to the 10th floor above ground). As shown in FIG. 10, the first natural frequency f1 of building B1 is f 1x = 1.37 Hz, f 1y = 1.32 Hz. Also, the first natural frequency f gMHVR of the ground G1 near building B1 was f gMHVR = 3.76 Hz. From the first natural frequency f1 of building B1 and the first natural frequency f gMHVR of the ground G1, the building resonance risk index is R x = 1.07, R y = 1.04, and the building resonance risk index R for building B1 is calculated as R = 1.07.

[0066] Also, the MHVR of the ground G1 and the pseudo ground amplification factor pSAF estimated using the learned model from the MHVR are as shown in FIG. 11, the peak frequency f gSAF is 3.9 Hz, and the peak value A gSAF is 12.5. Also, the ground risk index K g calculated based on the estimated pseudo ground amplification factor pSAF is K g = 40.1.

[0067] FIG. 12 is a graph showing the measurement results of the ambient vibration of a building B2 different from building B1. Building B2 is a building with a steel frame reinforced concrete structure (SRC structure) and 6 floors (from the basement 1st floor to the 6th floor above ground). As shown in FIG. 12, the first natural frequency f1 of building B2 is f1x = 2.30 Hz, f 1y = 3.17 Hz. Also, the fundamental natural frequency f of the ground G2 near Building B2 gMHVR was f gMHVR = 1.71 Hz. From the fundamental natural frequency f1 of Building B2 and the fundamental natural frequency f of the ground G2 gMHVR in the first horizontal direction (NS direction) and the second horizontal direction (EW direction) respectively, the building resonance risk indices are R x = 3.29, R y = 1.49, and the building resonance risk index R for Building B2 is calculated as R = 3.29

[0068] Also, the pseudo-ground amplification factor pSAF estimated using the MHVR of the ground G2 and the learned model from the MHVR is as shown in Fig. 13, and the peak frequency f gSAF is 1.7 Hz, and the peak value A gSAF is 12.5. Also, the ground risk index K g calculated based on the estimated pseudo-ground amplification factor pSAF g was K

[0069] Based on the building resonance risk index R and the ground risk index K for the above-mentioned Buildings B1 and B2 g when the comprehensive risk indices of Buildings B1 and B2 are evaluated in nine levels based on the table in Fig. 8, the comprehensive risk index of Building B1 can be evaluated as B, and the comprehensive risk index of Building B2 can be evaluated as B. As described above, from the vibration data of the buildings B1 and B2 to be evaluated and the ground G1 and G2 near the buildings, the resonance risk of the buildings and the ground risk can be calculated, and the seismic risk of the buildings considering the characteristics of the ground can be easily and accurately evaluated by these combinations

[0070] In the above embodiment, the comprehensive risk index representing the seismic risk of the building considering the characteristics of the ground is calculated by combining the building resonance risk index R and the ground risk index K g However, it is not limited to this. The seismic risk assessment device 1 calculates the building resonance risk R representing the seismic risk of the building and the ground risk index K representing the seismic risk of the ground gIt may also be independently evaluated. Thereby, it is possible to easily and accurately perform a comparative evaluation of the seismic risks of a plurality of buildings or a comparative evaluation of the seismic risks of the ground at a plurality of locations.

[0071] In addition, the seismic risk evaluation according to the above embodiment can be realized using an ordinary computer system. For example, by distributing a computer program for executing the seismic risk evaluation according to the above embodiment via a network such as the Internet and installing the computer program in a computer, the computer device can function as the above seismic risk evaluation device.

Industrial Applicability

[0072] The present invention is suitable for evaluating the seismic risks of the ground and buildings.

Explanation of Signs

[0073] 1 Seismic risk evaluation 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 evaluation unit, 12 Storage unit, 13 Display unit, 14 Input unit, 21 Server, 22 Vibration pickup

Claims

1. Calculating a first horizontal natural frequency and a second horizontal natural frequency orthogonal to the first horizontal direction from the constant minute movement information of the top floor and the bottom floor of the building to be evaluated; Calculating a Fourier spectrum amplitude ratio of the horizontal movement and the vertical movement of the ground from the constant minute movement information of the ground near the building, and calculating the natural frequency of the ground from the Fourier spectrum amplitude ratio; Comprising a building resonance risk calculation unit that calculates a building resonance risk index representing the risk due to resonance of the building based on the magnitude of the difference between the natural frequency of the building and the natural frequency of the ground; The building resonance risk index is calculated using the following formula: 【Number 1】 An earthquake risk assessment device characterized by the above.

2. The Fourier spectrum amplitude ratio is calculated using the following formula: 【Number 2】 The earthquake risk assessment device according to claim 1, characterized by the above.

3. Calculating a first horizontal natural frequency and a second horizontal natural frequency orthogonal to the first horizontal direction from the constant minute movement information of the top floor and the bottom floor of the building to be evaluated; Calculating a Fourier spectrum amplitude ratio of the horizontal movement and the vertical movement of the ground from the constant minute movement information of the ground near the building, and calculating the natural frequency of the ground from the Fourier spectrum amplitude ratio; Calculating a building resonance risk index representing the risk due to resonance of the building based on the magnitude of the difference between the natural frequency of the building and the natural frequency of the ground using the following formula: 【Number 3】 An earthquake risk assessment method characterized by the above.

4. A computer, Calculating a first horizontal natural frequency and a second horizontal natural frequency orthogonal to the first horizontal direction from the constant minute movement information of the top floor and the bottom floor of the building to be evaluated; Calculating a Fourier spectrum amplitude ratio of the horizontal movement and the vertical movement of the ground from the constant minute movement information of the ground near the building, and calculating the natural frequency of the ground from the Fourier spectrum amplitude ratio; A building resonance risk calculation unit that calculates a building resonance risk index representing the risk due to resonance of the building based on the magnitude of the difference between the natural frequency of the building and the natural frequency of the ground using the following formula; [Number 4] A program that functions as.

Images