Earthquake vibration information generation device, earthquake vibration information output method, risk evaluation method, and program

Abstract

To improve accuracy of risk evaluation for buildings against earthquakes.SOLUTION: An earthquake vibration information generation device includes: an individual earthquake spectrum acquisition unit that acquires individual earthquake spectra indicating the relationship between a period and response acceleration of an individual earthquake which constitutes a uniform hazard spectrum being an acceleration response spectrum with an arbitrary excess probability in a predetermined period uniform across all period bands on an engineering base surface for a target site where a building is located; a selection unit that selects one or more individual earthquake spectra with high contribution in the period band that affects the earthquake response of the building; a scaling unit that scales the response acceleration axis of the individual earthquake spectrum to the response acceleration axis of the uniform hazard spectrum; and an earthquake vibration set generation unit that generates multiple earthquake vibrations corresponding to the target spectrum as the vibration set representing the occurrence probability of the earthquake vibration at the target site with the one or more individual scaled earthquake spectra as the target spectra.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a ground motion information generation device, a ground motion information output method, a risk assessment method, and a program.

Background Art

[0002] Conventionally, various methods for evaluating the seismic risk of buildings and the like have been proposed. For example, Patent Document 1 discloses a method for evaluating the seismic performance of a structure using a uniform hazard spectrum.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

[0004] In the prior art, there is a quantitative seismic performance evaluation program for a structure that functions as response value calculation means for inputting a plurality of ground motions with occurrence probabilities assumed during the service life at the installation position of the structure and calculating the maximum response values with occurrence probabilities of acceleration and deformation generated in the target structure according to the response characteristics, expectation value calculation means for calculating the seismic response expectation values of acceleration and deformation generated in the target structure during the service life from the maximum response values of acceleration and deformation and the occurrence probabilities, and performance evaluation means for evaluating the seismic performance of the target structure using the product or the reciprocal of the seismic response expectation values of acceleration and deformation as a seismic performance index. In order to calculate the maximum response values with occurrence probabilities of acceleration and deformation generated in the target structure, ground motions with occurrence probabilities are used, and a uniform hazard spectrum corresponding to a plurality of occurrence probabilities is For each seismic source calculated. It is also shown that the response value of the structure is calculated by inputting the time history waveform with occurrence probability for each earthquake source. Since it requires extremely large labor and time to obtain the response values for all earthquake sources that affect the structure in such a manner, there is a risk that the design cost and design period will become enormous.

Summary of the Invention

Problems to be Solved by the Invention

[0005] However, in the prior art as described above, the characteristics of ground motions that can actually occur at the location where the building stands are not fully taken into account, and there is a problem that the accuracy of the risk assessment of the building against earthquakes is not necessarily sufficient.

[0006] The present invention has been made to solve the above problems, and an object thereof is to provide a ground motion information generation device, a ground motion information output method, and a program capable of enhancing the accuracy of risk assessment of a building against earthquakes.

Means for Solving the Problems

[0007] One embodiment of the present invention includes an individual earthquake spectrum acquisition unit that acquires an individual earthquake spectrum showing the relationship between the period and the response acceleration of an individual earthquake that constitutes a uniform hazard spectrum, which is an acceleration response spectrum having an arbitrary exceedance probability in a predetermined period that is uniform in the entire period band on the engineering bedrock surface for the target location where the building stands; a selection unit that selects one or more of the individual earthquake spectra having a high contribution degree in the period band that affects the earthquake response of the building from among the individual earthquake spectra; a scaling unit that scales the response acceleration axis of the selected one or more individual earthquake spectra to the response acceleration axis of the uniform hazard spectrum; and a ground motion set generation unit that generates a plurality of ground motions corresponding to the target spectrum as a ground motion set indicating the occurrence probability of ground motions at the target location, with the scaled one or more individual earthquake spectra as the target spectrum. The ground motion information generation device is provided with these components.

[0008] One embodiment of the present invention is a uniform hazard spectrum acquisition unit that acquires a uniform hazard spectrum, which is an acceleration response spectrum having an arbitrary exceedance probability in a predetermined period that is uniform across all period bands on the engineering base surface for a target location where a building is to be constructed, a decomposition unit that decomposes the acquired uniform hazard spectrum into individual earthquake spectra showing the relationship between the period and the response acceleration of individual earthquakes at the target location, a selection unit that selects one or more of the individual earthquake spectra having a high contribution degree in the period band that affects the seismic response of the building from among the decomposed individual earthquake spectra, a scaling unit that scales the response acceleration axis of the selected one or more individual earthquake spectra to the response acceleration axis of the uniform hazard spectrum, and a ground motion set generation unit that generates a plurality of ground motions corresponding to the target spectrum as a ground motion set showing the occurrence probability of ground motions at the target location, using the scaled one or more individual earthquake spectra as the target spectrum. The ground motion information generation device is provided with these components.

[0009] One embodiment of the present invention is to obtain an individual earthquake spectrum showing the relationship between the period and the response acceleration of an individual earthquake that constitutes a uniform hazard spectrum, which is an acceleration response spectrum having a predetermined exceedance probability that is uniform across all period bands on the engineering base surface for a target location where a building is to be constructed, select one or more of the individual earthquake spectra having a relatively high contribution degree in the period band that affects the seismic response of the building from among the acquired individual earthquake spectra, scale the response acceleration axis of the selected one or more individual earthquake spectra to the response acceleration axis of the uniform hazard spectrum, and use the scaled one or more individual earthquake spectra as the target spectrum to generate a plurality of ground motions corresponding to the target spectrum as a ground motion set showing the occurrence probability of ground motions at the target location. This is a ground motion information output method using a computer having these operations.

[0010] One embodiment of the present invention is a risk assessment method using a computer, comprising: acquiring the set of ground motions generated using the above-described ground motion information output method; and evaluating the risk of a building at the target location based on the acquired set of ground motions.

[0011] One embodiment of the present invention is to cause a computer to: acquire individual earthquake spectra showing the relationship between the period and the response acceleration of individual earthquakes that constitute a uniform hazard spectrum, which is an acceleration response spectrum having a predetermined exceedance probability that is uniform in the entire period band on the engineering bedrock surface for the target location where the building is located; select one or more of the individual earthquake spectra having a relatively high contribution degree in the period band that affects the seismic response of the building from among the acquired individual earthquake spectra; scale the response acceleration axis of the selected one or more individual earthquake spectra to the response acceleration axis of the uniform hazard spectrum; A program for causing the scaled one or more individual earthquake spectra to be used as target spectra and generating a plurality of ground motions corresponding to the target spectra as a set of ground motions indicating the occurrence probability of ground motions at the target location.

Advantages of the Invention

[0012] According to this invention, it is possible to provide a ground motion information generation device, a ground motion information output method, a risk assessment method, and a program that can improve the accuracy of risk assessment of buildings against earthquakes.

Brief Description of the Drawings

[0013]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiment for Carrying Out the Invention

[0014] [Prior Art] In order to quantitatively evaluate future earthquake risks, it is very useful to estimate the exceedance probability within a predetermined period for the degree of damage caused by the earthquake response of real estate, facilities, etc. (hereinafter, these are collectively referred to as buildings) in order to appropriately evaluate the asset value when purchasing the asset. If the relationship between earthquake risk and construction cost is known at the time of building construction, it becomes possible to evaluate the appropriate effect on investment, and it becomes possible to select specifications regarding seismic resistance and for the owner to make appropriate decisions, etc. Also, as part of the securitization of real estate and corporate risk management, by quantifying the risk due to earthquakes, it becomes possible to create indicators for the implementation of seismic reinforcement work, the selection of construction methods, and specific preparations such as insurance (guarantee) and savings for future earthquakes. Taking the securitization of real estate as an example, when a high earthquake risk is evaluated, it may be necessary to consider implementing earthquake insurance or alternative seismic retrofits, etc. The invention according to this embodiment targets a method for generating ground motions having a predetermined exceedance probability considering source characteristics, which is necessary for quantitatively evaluating earthquake risks, and a set of ground motions obtained thereby.

[0015] Regarding the seismic design of buildings, the Building Standards Act requires that designs for safety against damage and collapse of buildings be carried out for infrequently occurring ground motions (medium earthquakes) and extremely infrequently occurring ground motions (large earthquakes), respectively. Generally, seismic forces are calculated using the horizontal seismic intensity in the hydrodynamic pressure calculation. However, in the time history route, the time history waveform of the ground motion is created by adding phase information using the respective spectra in the release engineering base defined in the Ministry of Construction Notification No. 1461 regarding the Building Standards Act (hereinafter referred to as the "Notification"), and the response of the building is calculated by performing a time history response analysis to check whether the design criteria are satisfied.

[0016] In addition, in the performance evaluation by time history response analysis, the Japan Building Center's "Business Method Manual for Building Performance Evaluation by Time History Response Analysis (2020)" stipulates that for observed waves, "three or more waves appropriately selected considering the characteristics of the construction site and the building among representative observed seismic waves in the past" should be used. In practice, the so-called standard three waves, namely "El Centro 1940 NS, EW, UD", "Taft 1952 NS, EW, UD", and "Hachinohe 1968 NS, EW, UD", are widely used.

[0017] Ground motions such as these standard three waves do not appropriately consider the earthquake occurrence frequency around the site, the scale of the earthquake, the distance from the fault and the earthquake source, the ground characteristics, and other effects on the ground motion and the building. Therefore, they do not contain probability information such as the occurrence probability or the exceedance probability within a specified period, the seismic risk of the building is unknown, and the asset value of the building over time cannot be evaluated. Note that the Notification states that "this does not apply when appropriately considering the earthquake occurrence frequency around the site, the scale of the earthquake, the distance from the fault and the earthquake source, the ground characteristics, and other effects on the ground motion and the building." However, no specific method has been clarified.

[0018] On the one hand, by means of probabilistic seismic hazard analysis using the characteristics of each seismic source, ground motion prediction methods, and the probability of earthquake occurrence, it is possible to probabilistically determine the occurrence probability (exceedance probability within a predetermined period) for ground motion. Utilizing this, a "Uniform Hazard Spectra" can be obtained.

[0019] Figure 1 is a diagram showing an example of a uniform hazard spectrum. The uniform hazard spectrum is obtained by connecting the values of the response spectra with the same exceedance probability, with the period on the horizontal axis, based on the hazard curve for the response spectra for each period. It represents ground motion with the same exceedance probability over all periods, and the effects of various earthquakes are integrated according to the degree of difference for each period. That is, the uniform hazard spectrum is an acceleration response spectrum with a uniform exceedance probability over the entire period band, obtained by adding up the occurrence probabilities (exceedance probabilities) of all seismic sources for a predetermined response acceleration at each period. In the following description, the uniform hazard spectrum is also referred to as the "uniform hazard spectrum U" with the symbol U attached.

[0020] In recent years, there have been many voices calling for continuous use even after a major earthquake, and the practical application of performance design that can meet various requirements of building owners is desired. There is a method of evaluating the uncertainty of the loads and load-bearing capacities that will act on a building in the future based on probability and statistics, and evaluating and designing the performance level of a building using the probability of the building being in an unfavorable state during the service period as a quantitative measure. Against the backdrop of such evaluation and design, there was a method of directly using the uniform hazard spectrum itself as the external force due to an earthquake in order to calculate the damage degree and exceedance probability of a building. However, since the uniform hazard spectrum is obtained for all seismic sources that affect the target location, it has the following characteristics.

[0021] A uniform hazard spectrum cannot be associated with any single ground motion. This is because, generally, the ground motions with the highest contribution (highest occurrence probability) at each period are caused by different earthquakes. This is because, at short periods, ground motions caused by small-scale and nearby earthquake sources contribute significantly, while at long periods, ground motions caused by large-scale and distant earthquake sources tend to contribute more. Information about the earthquake, such as the magnitude and distance from the earthquake source, cannot be obtained from the uniform hazard spectrum. Also, the fact that the correlation between each period does not follow a lognormal distribution like that of a single ground motion is another reason why it cannot be associated with a single ground motion, and damage estimation based on the uniform hazard spectrum does not correspond to the damage caused by an actual earthquake event. The response spectra of each earthquake with the same exceedance probability as the uniform hazard spectrum are smaller than the uniform hazard spectrum at all periods.

[0022] Using the uniform hazard spectrum with the above characteristics as the response spectrum of ground motion with a predetermined exceedance probability to calculate the response of a building and estimate the damage to evaluate the earthquake risk has the following problems. The uniform hazard spectrum is obtained for all earthquake sources affecting the target location and cannot be associated with a single ground motion (earthquake). Therefore, the shape of the response spectrum is significantly different from that of a single earthquake that may actually occur. For this reason, the earthquake damage estimated using the uniform hazard spectrum with a predetermined exceedance probability is likely to be different from the earthquake damage that may actually occur. In particular, when significant plasticization of the building and a long natural period are expected, the impact becomes greater.

[0023] [Overview of the Embodiment] The overview of this embodiment is as follows. The location where the building stands (building site), etc. is taken as the target location. Obtain a uniform hazard spectrum considering all the seismic sources that affect the target location. By using the uniform hazard spectrum considering all the seismic sources that affect the target location, the impact of an earthquake can be estimated without being limited to a specific seismic source. Perform a decomposition of the seismic source (hereinafter also simply referred to as "decomposition") on the obtained uniform hazard spectrum to obtain a plurality of average response spectra. Select one or more average response spectra that include ground motions with the highest contribution (highest probability) at a plurality of representative periods in the period band that affects the target building. Scale the selected average response spectrum to the amplitude of the uniform hazard spectrum. Use the scaled average response spectrum as the target spectrum. Note that, using the scaled average response spectrum as the geometric mean, a target spectrum (40 earthquakes × fault orthogonal and parallel directions) in which the variance of each period and the correlation between all periods follow a lognormal distribution may be randomly generated using Monte Carlo simulation or the like. Select ground motions that match one or more characteristics of the seismic source information such as the type of the selected high - contribution ground motion (inland active fault type, trench type), magnitude, distance from the seismic source, average shear wave velocity at a depth of 100 m (Vs30), and fault type (Dip / Normal Strike) from the observed wave and predicted wave databases and that conform to the above - mentioned target spectra. Scale the selected ground motion to be the geometric mean in the period band that affects the target building and to minimize the error with respect to the target spectrum. By the above - mentioned method, a set of ground motions with the characteristics of actual ground motions that can occur and having a predetermined occurrence probability can be obtained according to the structural characteristics of the building at the target construction site.

[0024] [Configuration and Operation of the Ground Motion Information Generation System] The configuration and operation of the ground motion information generation system 1 for implementing the above - described overview will be described.

[0025] FIG. 2 is a diagram showing an example of the functional configuration of the seismic motion information generation system 1 of the present embodiment. FIG. 3 is a diagram showing an example of the flow of the operation of the seismic motion information generation device 10 of the present embodiment. The seismic motion information generation system 1 includes a seismic motion information generation device 10, a uniform hazard spectrum database 20, a natural period information database 30, a seismic motion database 40, and an output device 50.

[0026] The seismic motion information generation device 10 includes an arithmetic unit 100 and a storage unit 200. The storage unit 200 includes, for example, a semiconductor memory, a hard disk device, etc., and stores programs and data used by the arithmetic unit 100. The arithmetic unit 100 includes, for example, a central processing unit (CPU), and provides various functions by operating based on the programs and data stored in the storage unit 200.

[0027] The arithmetic unit 100 includes, as its functional units, a uniform hazard spectrum acquisition unit 101, a decomposition unit 102, a selection unit 103, a scaling unit 104, a seismic motion information acquisition unit 105, and a seismic motion set generation unit 106. Further, the arithmetic unit 100 may include, as its functional units, a natural period information acquisition unit 111, a target spectrum generation unit 112, a magnification factor acquisition unit 113, and a ground surface individual earthquake spectrum calculation unit 114.

[0028] (Step S10) The uniform hazard spectrum acquisition unit 101 acquires a uniform hazard spectrum U from the uniform hazard spectrum database 20. The uniform hazard spectrum database 20 is, for example, a database operated by a public institution related to seismic research, and provides a uniform hazard spectrum U. As described above, the uniform hazard spectrum U is an acceleration response spectrum having a predetermined exceedance probability that is uniform over the entire period band on the engineering base surface. The uniform hazard spectrum acquisition unit 101 acquires a uniform hazard spectrum U for the target location where the building is located from the uniform hazard spectrum database 20.

[0029] That is, the uniform hazard spectrum acquisition unit 101 acquires a uniform hazard spectrum U, which is an acceleration response spectrum having a predetermined exceedance probability that is uniform over all periods on the engineering bedrock surface, for the target location where the building is located.

[0030] Since the uniform hazard spectrum U on the engineering bedrock surface is not affected by the amplification of ground motion by the surface ground, the difference due to location becomes smaller compared to the ground surface. Utilizing this characteristic, if the uniform hazard spectrum U on the engineering bedrock surface is calculated in advance at regular intervals (for example, 10 - 50 km grid), the creation of ground motion groups can be greatly simplified by using the uniform hazard spectrum U closest to the target location.

[0031] Note that in order to calculate the uniform hazard spectrum U of the target location, it is usually necessary to calculate the ground motion for all earthquake sources that have an impact of 1000 or more, respectively, which requires an extremely large amount of time and labor. The 50 - year exceedance probabilities (50%, 10%, 2%) are respectively 50%: Rare earthquake 10%: Extremely rare earthquake 2%: Great earthquake that exceeds the design target but should be considered and can be treated as such.

[0032] The uniform hazard spectrum acquisition unit 101 acquires the uniform hazard spectrum U calculated for each of the plurality of exceedance probabilities for each of the plurality of exceedance probabilities.

[0033] (Step S20) The decomposition unit 102 decomposes the acquired uniform hazard spectrum U into individual earthquake spectra W that show the relationship between the period and the response acceleration of individual earthquakes at the target location. As described above, the uniform hazard spectrum U is an acceleration response spectrum having a uniform exceedance probability in the entire period band, which is obtained by adding up the occurrence probabilities (exceedance probabilities) of all seismic sources for a given response acceleration in each period. That is, the uniform hazard spectrum U is information obtained by integrating the spectra of multiple earthquakes. Decomposing the uniform hazard spectrum U into individual earthquake spectra W is also referred to as deaggregation into the individual earthquake spectra W.

[0034] FIG. 4 is a diagram showing an example of the decomposition of the uniform hazard spectrum U of the present embodiment. In the same figure [A], it is the uniform hazard spectrum U shown in FIG. 1. The uniform hazard spectrum U is acquired from the uniform hazard spectrum database 20. That is, the uniform hazard spectrum U shown in the same figure [A] is the uniform hazard spectrum U acquired by the uniform hazard spectrum acquisition unit 101.

[0035] In the same figures [B] to [D], an example of the individual earthquake spectra W obtained by decomposing the uniform hazard spectrum U is shown. In the same figure [B], an example of the individual earthquake spectrum W1 obtained by decomposing the uniform hazard spectrum U is shown. In the same figure [C], an example of the individual earthquake spectrum W2 obtained by decomposing the uniform hazard spectrum U is shown. The decomposition unit 102 decomposes the uniform hazard spectrum U into a plurality of individual earthquake spectra W (for example, n individual earthquake spectra W. n is a natural number). In the same figure [D], an example of the individual earthquake spectrum Wn obtained by decomposing the uniform hazard spectrum U is shown.

[0036] As an example, for a three-story steel frame building, deaggregation of the seismic source is performed for the uniform hazard spectrum with respect to representative periods (for example, 0.2 seconds, 0.5 seconds, 1.5 seconds) representing the period bands that affect the seismic response.

[0037] By decomposing the uniform hazard spectrum U into individual earthquake spectra W by the decomposition unit 102, it becomes possible to compare the respective individual earthquake spectra W with each other for a plurality of earthquakes that make up the uniform hazard spectrum U. For example, it becomes possible to select an individual earthquake spectrum W having a peak in a period band that affects the seismic response of the building to be determined from among a plurality of individual earthquake spectra W.

[0038] Here, with reference to FIG. 5, the variation in the response acceleration in the spectrum of a single earthquake will be described.

[0039] FIG. 5 is a diagram showing the relationship between the distance from the epicenter of a single earthquake and the response acceleration. As shown in the figure, in the spectrum of a single earthquake, there is a variation in the response acceleration at the distance from the epicenter (for example, 10 km). By performing statistical processing (for example, averaging) on the response acceleration of the spectrum of a single earthquake, it becomes possible to handle the spectrum of a single earthquake as one spectrum. In the present embodiment, the average of the response accelerations of the spectra of single earthquakes is referred to as the average response spectrum of a single earthquake. The "individual earthquake spectrum W" in the present embodiment corresponds to the average response spectrum of a single earthquake.

[0040] Note that in the above example, it has been described that the uniform hazard spectrum acquisition unit 101 acquires the uniform hazard spectrum U, and the decomposition unit 102 decomposes the acquired uniform hazard spectrum U into individual earthquake spectra W showing the relationship between the period and the response acceleration of individual earthquakes at the target location, but it is not limited to this. For example, the calculation unit 100 may include an individual earthquake spectrum acquisition unit that acquires individual earthquake spectra W that have been previously decomposed or are before being synthesized into the uniform hazard spectrum. That is, the individual earthquake spectrum acquisition unit acquires individual earthquake spectra W showing the relationship between the period and the response acceleration of individual earthquakes that make up the uniform hazard spectrum U, which is an acceleration response spectrum having an arbitrary exceedance probability uniformly in all period bands in a predetermined period on the engineering base surface for the target location where the building is located.

[0041] (Step S30) Return to FIG. 3, and the selection unit 103 selects one or more individual earthquake spectra W with high contribution in the period band that affects the seismic response of the building from the decomposed individual earthquake spectra W. Here, "high contribution" may be relative when comparing individual earthquake spectra W with each other, or may be absolute based on a certain threshold. For example, the selection unit 103 may select an individual earthquake spectrum W having a relatively high response acceleration in the period band that affects the seismic response of the building from among the plurality of decomposed individual earthquake spectra W.

[0042] As an example, the selection unit 103 may select the average response spectrum of the ground motion with the highest contribution (having the highest occurrence probability, that is, the most likely to occur) at each of the above-mentioned representative periods (0.2 seconds, 0.5 seconds, 1.5 seconds). That is, the selection unit 103 may select one or more individual earthquake spectra W with high contribution in a predetermined representative period band representing the period band that affects the seismic response of the building.

[0043] Also, for example, the selection unit 103 may select an individual earthquake spectrum W having a response acceleration exceeding a certain predetermined threshold in the period band that affects the seismic response of the building from among the plurality of decomposed individual earthquake spectra W.

[0044] Also, the period band that affects the seismic response of the building may be the natural period of the building. In this case, the natural period information acquisition unit 111 may be configured to acquire natural period information indicating the natural period of the building. This natural period may be given to the ground motion information generation device 10 by a user operating the ground motion information generation device 10, or may be provided from the natural period information database 30. The selection unit 103 selects one or more individual earthquake spectra W with high contribution in the period band that affects the seismic response of the building indicated by the acquired natural period information.

[0045] In this example, the selection unit 103 selects the individual earthquake spectrum Wk (k is a natural number) with a high contribution degree from among the n individual earthquake spectra W.

[0046] (Step S40) The scaling unit 104 scales the response acceleration axis of the selected one or more individual earthquake spectra W to the response acceleration axis of the uniform hazard spectrum U.

[0047] FIG. 6 is a diagram showing an example of the scaling by the scaling unit 104 of the present embodiment. In FIG. [A] of this figure, an example of the individual earthquake spectrum Wk selected by the selection unit 103 is shown. In FIG. [B] of this figure, an example of the scaling result of the individual earthquake spectrum W by the scaling unit 104 is shown. In this example, the scaling unit 104 expands the individual earthquake spectrum Wk to the individual earthquake spectrum Wks.

[0048] That is, the scaling unit 104 scales the average response spectrum on the engineering base surface to the amplitude of the uniform hazard spectrum U. Scaling is performed so that the average response spectrum touches the uniform hazard spectrum U at any period.

[0049] More specifically, the scaling unit 104 expands the response acceleration axis of the individual earthquake spectrum Wk so that the response acceleration of the individual earthquake spectrum Wks and the response acceleration of the uniform hazard spectrum U coincide at the period sp of the peak of the response acceleration of the individual earthquake spectrum Wk.

[0050] As described above, the uniform hazard spectrum U is an acceleration response spectrum having a uniform exceedance probability in the entire period band, in which the occurrence probabilities (exceedance probabilities) of all the earthquake sources are added together for a predetermined response acceleration at each period. Therefore, the wave height (that is, the amplitude, or the magnitude of the response acceleration) in the response acceleration axis direction of the individual earthquake spectrum W is smaller than the wave height in the response acceleration axis direction of the uniform hazard spectrum U.

[0051] Here, when the selection unit 103 selects a plurality of individual earthquake spectra W, the scaling unit 104 scales each of the selected plurality of individual earthquake spectra W. By scaling the individual earthquake spectra W decomposed from the uniform hazard spectrum U to the amplitude of the uniform hazard spectrum U to calculate a plurality of response spectra, while maintaining the relationship between the predetermined exceedance probability and the amplitude (response acceleration) at each period that the uniform hazard spectrum has, it is also possible to incorporate the characteristics of actual earthquake motions that can occur.

[0052] As described above, the calculation unit 100 may include an amplification factor acquisition unit 113 (not shown) and a ground surface individual earthquake spectrum calculation unit 114 (not shown) as its functional units. The amplification factor acquisition unit 113 acquires the amplification factor of the individual earthquake spectrum W from the engineering bedrock surface to the ground surface based on the surface ground characteristics of the target location. The ground surface individual earthquake spectrum calculation unit 114 calculates the individual earthquake spectrum W at the ground surface by amplifying one or more scaled individual earthquake spectra W by the acquired amplification factor.

[0053] Specifically, the ground surface individual earthquake spectrum calculation unit 114 considers the surface ground characteristics of the target location, calculates the amplification factor from the engineering bedrock surface to the ground surface of the scaled average response spectrum on the engineering bedrock surface, and multiplies the scaled average response spectrum to calculate the average response spectrum at the ground surface. As the surface ground characteristics, the average shear wave velocity (Vs30) from the ground surface to a depth of 100 m can be used.

[0054] (Step S50) Returning to FIG. 3, the ground motion set generation unit 106 uses one or more scaled individual earthquake spectra W as target spectra, and generates a plurality of ground motions corresponding to the target spectra as a ground motion set indicating the occurrence probability of ground motions at the target location.

[0055] Note that, as described above, the arithmetic unit 100 may include the target spectrum generation unit 112 as one of its functional units. In this case, the ground motion set generation unit 106 generates a plurality of ground motions corresponding to the target spectrum generated by the target spectrum generation unit 112 as a ground motion set indicating the occurrence probability of ground motions at the target location.

[0056] The target spectrum generation unit 112 generates a target spectrum in which the variance for each period and the correlation over all periods follow a lognormal distribution, using the individual earthquake spectrum W as the geometric mean.

[0057] As an example, the target spectrum generation unit 112 generates 40 target spectra each in the fault-normal and fault-parallel directions, in which the variance for each period and the correlation over all periods follow a lognormal distribution, using the mean response spectrum as the geometric mean and performing Monte Carlo simulations.

[0058] For the target spectrum scaled by the scaling unit 104 (or the target spectrum generated by the target spectrum generation unit 112), the ground motion set generation unit 106 sets the range for selecting ground motions based on information such as the earthquake source and the measurement location as follows. Type of earthquake: Inland active fault type Magnitude: 5.5 - 6.5 Distance from the earthquake source: ~150 km Average shear wave velocity (Vs30) at a depth of 100 m: 170 - 400 m / s By considering the type of fault and the velocity pulse characteristics in the earthquake source information, the characteristics of the ground motion can be more specifically identified.

[0059] The ground motion set generation unit 106 uses the ground motion database 40 (also referred to as the observed wave and predicted wave database) to select seismic waves that match the target spectrum from among the ground motion data that match the characteristics of the ground motion described above. The ground motion set generation unit 106 scales the selected seismic wave as necessary, calculates the sum of the squares of the errors at the target spectrum and the periods of the seismic waves for all seismic waves according to Equation (1), and selects the seismic waves for which the sum of the squares of the errors is minimized. Here, the period band affecting the target building is set to 0.1 second to 2.0 seconds.

[0060]

Equation

[0061] Here, lnS a (T j ) is the response spectrum of the selected seismic wave (scaled as necessary), that is, S a (T j ) is the response acceleration at period T j , and lnS a (S) (T j ) is the target spectrum.

[0062] Note that the ground motion set generation unit 106 may select a ground motion set with less error from the generated ground motion sets based on the errors regarding the geometric mean and the logarithmic standard deviation with respect to the target spectrum. In this case, the ground motion set generation unit 106 calculates the errors regarding the geometric mean and the logarithmic standard deviation with respect to the target spectrum for the ground motion sets selected to conform to each of the above-described target spectra according to Equations (2) and (3), respectively.

[0063]

Equation

[0064]

Equation

[0065] m lnSa (T j) is the geometric mean of the response accelerations at the period T j of the generated ground motion group, and μ lnSa (T j ) is the geometric mean of the response accelerations at the period T j of the target spectrum group. s lnSa (T j ) is the logarithmic standard deviation of the response accelerations at the period T j of the generated ground motion group, and σ lnSa (T j ) is the logarithmic standard deviation of the response accelerations at the period T j of the target spectrum group.

[0066] The ground motion set generation unit 106 selects a ground motion set for which those errors fall within a predetermined value or are minimized. By the above method, in the construction site of interest, according to the structural characteristics of the building, a ground motion group having the characteristics of actual ground motions that can occur, and having a predetermined occurrence probability and the variation as a natural phenomenon of the ground motions is obtained.

[0067] (Step S60) The ground motion set generation unit 106 outputs the generated ground motion set to the output device 50. Here, the output device 50 is a display device such as a display, a printing device such as a printer, or another computer device or the like.

[0068] By the above procedure, in the construction site of interest, according to the structural characteristics of the building, a ground motion group having the characteristics of actual ground motions that can occur and having a predetermined occurrence probability is obtained. When directly calculating the uniform hazard spectrum U on the ground surface by a ground motion prediction formula or the like, it is not necessary to calculate the amplification factor from the engineering bedrock surface of the mean response spectrum to the ground surface. When directly calculating the uniform hazard spectrum U, which is an acceleration response spectrum having a uniform exceedance probability in the entire period band, on the ground surface by a ground motion prediction formula or the like, it is not necessary to calculate the amplification factor from the engineering bedrock surface of the mean response spectrum to the ground surface.

[0069] Note that, based on the set of ground motions output in step S60 and a known analysis method or evaluation method, the risk of the building at the target location may be evaluated.

[0070] The set of ground motions generated by the ground motion information generation device 10 described above solves the problems of the conventional method that uses the uniform hazard spectrum as the response spectrum of ground motions having a predetermined exceedance probability. That is, the ground motion information generation device 10 of the present embodiment scales the average response spectrum of a single earthquake including the earthquake with the highest contribution (the highest probability) at each of a plurality of representative periods in the period band affecting the target building to the amplitude of the uniform hazard spectrum by re-decomposing the earthquake source, and obtains a plurality of response spectra. The set of ground motions generated by the ground motion information generation device 10 configured as described above can also have the characteristics of ground motions that can actually occur while maintaining the relationship between the predetermined exceedance probability and the amplitude (response acceleration) at each period that the uniform hazard spectrum has.

[0071] Furthermore, by considering a plurality of earthquakes instead of a single earthquake, the uncertainty of earthquake occurrence can be compensated for. As a result, it is possible to appropriately evaluate and predict the damage caused by a single earthquake that can occur with the highest probability, which cannot be estimated by simply using the uniform hazard spectrum itself as the ground motion. Even when it is expected that the natural period will become longer as the plasticization of the building progresses due to the earthquake response, since the shape of the response spectrum has the same characteristics as the actual ground motion, it is possible to appropriately estimate the building response.

[0072] Since the earthquake motions are selected and scaled such that each average response spectrum in the representative period becomes a geometric mean in the period band that affects the target building, the variation in earthquake motions can be considered, but the characteristics of the variation cannot be appropriately reproduced. Empirically, it is known that the variation in earthquake motions follows a lognormal distribution, and the variation in actual earthquake motions can be quantitatively considered. As a result, it is possible to create a set of earthquake motions that has the characteristics of earthquake motions that can actually occur while having an amplitude equivalent to a uniform hazard spectrum with a predetermined probability of exceedance, and that also quantitatively considers the variation inherent in earthquake motions as a natural phenomenon. The set of earthquake motions created by this method can appropriately calculate the degree of damage and the probability of exceedance of a building in a method for evaluating and designing the performance level of a building using the probability that the building will be in an unfavorable state during its service life as a quantitative measure. In the construction site targeted above, according to the structural characteristics of the building, by accurately and quantitatively evaluating the seismic risk using a group of earthquake motions that have the characteristics of earthquake motions that can actually occur and that have a predetermined probability of occurrence and the variation inherent in earthquake motions as a natural phenomenon, it is possible to set an appropriate premium for earthquake insurance (guarantee).

[0073] The representative period can be arbitrarily set according to the building to be considered or the production facilities within the building, etc. As a result, the present invention is applicable to structures (for example, in buildings, from single-family houses to high-rise buildings, condominiums, factory buildings, and plants) and facilities having any natural period. The present invention is not limited to the architectural field, but can be widely applied to civil engineering fields, industrial production fields, etc. The group of earthquake motions is applicable not only to the risk assessment of existing buildings, but also to the design of new buildings based on the target seismic risk.

[0074] When calculating the seismic response of a target building or facilities using this earthquake motion group, in addition to the time history response analysis using the time history waveform, a method using the representative load-deformation relationship and response spectrum of the target object (equivalent linearization method) can also be applied. In calculating the seismic response, in addition to structural members, non-structural members and furniture and facilities inside the building are also included. The seismic risk can be calculated based on the occurrence probability of earthquake motion after considering the variations in the seismic response of buildings or facilities. For industrialized buildings where the members, joints, design methods, and construction methods that make up the building are standardized and used in multiple buildings, compared with general buildings where the design is carried out for each building and the construction methods are also diverse, it is possible to suppress the variations in the response of the target building. Also, in these industrialized buildings, since the responses of members, joints, and the entire building can be verified in advance through experiments or analysis, etc., by using them to calculate the response of the target building, a more accurate calculation of the seismic risk is possible.

[0075] Here, taking the collapse risk of a building as an example, the annual collapse risk λ can be calculated by the following equations (4) and (5). C can be calculated.

[0076]

Equation

[0077]

Equation

[0078] Here, P(C|EP) is the probability that the target building collapses for this earthquake motion group, EP is the probability of exceedance in 50 years for this earthquake motion, and λ EP is the annual occurrence probability of this earthquake motion group.

[0079] As described above, the embodiments of the present invention have been described in detail with reference to the drawings. However, the specific configuration is not limited to this embodiment, and appropriate changes can be made without departing from the gist of the present invention. The configurations described in the above-described embodiments may be combined.

[0080] Note that each part included in each of the above-described embodiments may be realized by dedicated hardware, or may be realized by a memory and a microprocessor.

[0081] Note that each part included in each device may be constituted by a memory and a CPU (Central Processing Unit), and the function thereof may be realized by loading a program for realizing the function of each part included in each device into the memory and executing it.

[0082] Further, a program for realizing the function of each part included in each device may be recorded on a computer-readable recording medium, and the program recorded on this recording medium may be read into a computer system and executed, so that processing by each part included in the control unit may be performed. Here, the “computer system” shall include hardware such as an OS and peripheral devices.

[0083] Also, the “computer system” shall include a homepage providing environment (or display environment) if the WWW system is being used. Also, the “computer-readable recording medium” refers to portable media such as flexible disks, magneto-optical disks, ROMs, CD-ROMs, and storage devices such as hard disks built into a computer system. Furthermore, the “computer-readable recording medium” refers to something that dynamically holds a program for a short time, like a communication line when transmitting a program via a network such as the Internet or a communication line such as a telephone line, and also includes something that holds a program for a certain time, like volatile memory inside a computer system that becomes a server or a client in that case. Also, the above program may be for realizing a part of the aforementioned functions, and may further be realizable in combination with a program already recorded in the computer system for realizing the aforementioned functions.

Explanation of Reference Numerals

[0084] 1…Ground motion information generation system, 10…Ground motion information generation device, 20…Uniform hazard spectrum database, 30…Natural period information database, 40…Ground motion database, 50…Output device, 100…Calculation unit, 101…Uniform hazard spectrum acquisition unit, 102…Decomposition unit, 103…Selection unit, 104…Scaling unit, 105…Ground motion information acquisition unit, 106…Ground motion set generation unit, 111…Natural period information acquisition unit, 112…Target spectrum generation unit, 113…Amplification factor acquisition unit

Claims

1. An individual earthquake spectrum acquisition unit that acquires an individual earthquake spectrum showing the relationship between the period and the response acceleration of an individual earthquake that constitutes a uniform hazard spectrum, which is an acceleration response spectrum having an arbitrary exceedance probability in a predetermined period that is uniform in all period bands on the engineering base surface for the target location where the building is to be constructed; A selection unit that selects one or more of the individual earthquake spectra having a high contribution degree in the period band that affects the seismic response of the building among the individual earthquake spectra; A scaling unit that scales the response acceleration axis of the selected one or more individual earthquake spectra to the response acceleration axis of the uniform hazard spectrum; An earthquake motion set generation unit that generates a plurality of earthquake motions corresponding to the target spectrum as an earthquake motion set showing the occurrence probability of earthquake motions at the target location, using the scaled one or more individual earthquake spectra as the target spectrum; An earthquake motion information generation device comprising the above.

2. A uniform hazard spectrum acquisition unit that acquires a uniform hazard spectrum, which is an acceleration response spectrum having an arbitrary exceedance probability in a predetermined period that is uniform in all period bands on the engineering base surface for the target location where the building is to be constructed; A decomposition unit that decomposes the acquired uniform hazard spectrum into individual earthquake spectra showing the relationship between the period and the response acceleration of individual earthquakes at the target location; A selection unit that selects one or more of the individual earthquake spectra having a high contribution degree in the period band that affects the seismic response of the building among the decomposed individual earthquake spectra; A scaling unit that scales the response acceleration axis of the selected one or more individual earthquake spectra to the response acceleration axis of the uniform hazard spectrum; An earthquake motion set generation unit that generates a plurality of earthquake motions corresponding to the target spectrum as an earthquake motion set showing the occurrence probability of earthquake motions at the target location, using the scaled one or more individual earthquake spectra as the target spectrum; An earthquake motion information generation device comprising the above.

3. An amplification factor acquisition unit that acquires the amplification factor of the individual earthquake spectrum from the engineering base surface to the ground surface based on the surface ground characteristics of the target location; A ground surface individual earthquake spectrum calculation unit that calculates an individual earthquake spectrum on the ground surface by amplifying one or more of the scaled individual earthquake spectra by the obtained amplification factor; further comprising The seismic motion information generation device according to claim 1 or claim 2.

4. A target spectrum generation unit that generates, as the target spectrum, a spectrum in which the correlation between the dispersion for each period and the entire period is a multinomial logarithmic normal distribution, with the individual earthquake spectrum as the geometric mean The seismic motion information generation device according to claim 1 or claim 2, further comprising.

5. The uniform hazard spectrum acquisition unit acquires the uniform hazard spectra calculated for each of the plurality of exceedance probabilities for each of the plurality of exceedance probabilities The seismic motion information generation device according to claim 2.

6. A natural period information acquisition unit that acquires natural period information indicating the natural period of the building further comprising The selection unit selects one or more of the individual earthquake spectra having a high contribution degree in the period band that affects the seismic response of the building indicated by the acquired natural period information The seismic motion information generation device according to claim 1 or claim 2.

7. The selection unit selects one or more of the individual earthquake spectra having a high contribution degree in a predetermined representative period band representing the period band that affects the seismic response of the building The seismic motion information generation device according to claim 1 or claim 2.

8. Obtaining an individual earthquake spectrum showing the relationship between the period and the response acceleration of an individual earthquake that constitutes a uniform hazard spectrum, which is an acceleration response spectrum having a predetermined exceedance probability that is uniform over the entire period band on the engineering bedrock surface for the target location where the building is located; selecting one or more of the individual earthquake spectra having a relatively high contribution degree in the period band that affects the seismic response of the building from among the obtained individual earthquake spectra; scaling the response acceleration axis of the selected one or more individual earthquake spectra to the response acceleration axis of the uniform hazard spectrum; using the scaled one or more individual earthquake spectra as target spectra, and generating a plurality of ground motions corresponding to the target spectra as a ground motion set indicating the occurrence probability of ground motions at the target location; A ground motion information output method using a computer having.

9. Obtaining the set of ground motions generated by using the ground motion information output method according to claim 8; Evaluating the risk of a building at the target location based on the obtained set of ground motions; A risk evaluation method using a computer having the above.

10. For a computer, Obtaining an individual earthquake spectrum showing the relationship between the period and the response acceleration of an individual earthquake that constitutes a uniform hazard spectrum, which is an acceleration response spectrum having a predetermined exceedance probability that is uniform in all period bands on the engineering bedrock surface for the target location where the building is located; Selecting one or more of the individual earthquake spectra having a relatively high contribution degree in the period band that affects the seismic response of the building among the obtained individual earthquake spectra; Scaling the response acceleration axis of the selected one or more individual earthquake spectra to the response acceleration axis of the uniform hazard spectrum; Using the scaled one or more individual earthquake spectra as target spectra, generating a plurality of ground motions corresponding to the target spectra as a set of ground motions indicating the occurrence probability of ground motions at the target location; A program for causing the above to be executed.

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