JP6560609B2 - Seismic intensity measuring apparatus and method - Google Patents

Description

  The present invention relates to a technique for setting a sequence of natural periods of a structure model suitable for calculating an SI value that is a kind of estimated earthquake damage value.

  There is a control seismometer as a device for controlling various systems according to the intensity of an earthquake and preventing the occurrence of damage and the occurrence of a secondary disaster when an earthquake occurs. The seismometer for control is incorporated in various facilities such as transportation, city gas, electric power, water supply, etc., and is controlled so that the system is urgently stopped as required from the result of the estimation calculation of earthquake damage. In a seismometer for controlling city gas facilities, an SI (Spectrum Intensity) value, which is a kind of estimated earthquake damage value, is used as a measure of the intensity of ground motion (see Patent Document 1 and Patent Document 2).

  The control seismometers disclosed in Patent Document 1 and Patent Document 2 obtain the velocity response from time to time by inputting the acceleration of the ground motion to the arithmetic unit that satisfies the equation of motion of the structure model of one-degree-of-freedom one-mass point damping system. The estimated SI value is calculated from the maximum value Sv of the speed response. The velocity response has a correlation with the fracture energy to the structure.

JP-A-8-15442 JP-A-8-36062

  One important parameter for the SI value calculation is the number of natural periods of the structure model. This is the number of steps for dividing the interval from the natural period T = 0.1 sec to 2.5 sec. Increasing the number of steps of the natural period T (decreasing the step size) improves the accuracy of the SI value.

  However, if the number of steps of the natural period T is increased, the amount of calculation of the computer increases, so that it becomes difficult to calculate the SI value with a computer having a limited ability to provide an inexpensive product, and the consumption of the computer Increase in power and heat generation becomes a design problem. Therefore, it has been necessary to improve the determination method of the natural period T for balancing the number of steps (or step width) of the natural period T and the power consumption.

  Conventionally, the natural period T is determined by empirical steps (for example, an arithmetic progression), and simulations are performed in which accelerations of various well-known earthquakes and various seismic waves characterized by frequency characteristics are input to SI value arithmetic expressions. The evaluation of the SI value estimation accuracy from a statistical point of view evaluates whether the setting of the natural period T is appropriate.

  For this reason, when the estimation accuracy of the SI value cannot be satisfied, it takes time for trial and error to perform the simulation again by making the step of the natural period T finer or changing the step size in the middle. In addition, according to the evaluation method as described above, the estimation accuracy of the SI value can be guaranteed for the seismic wave used in the simulation, but there is a problem that the accuracy for other seismic waves cannot be guaranteed.

  The present invention has been made to solve the above-described problem, and is a method that does not rely on trial and error to calculate a sequence of natural periods that is suitable for calculating an SI value and that can suppress the amount of calculation required to calculate the SI value. An object of the present invention is to provide a seismic intensity measuring apparatus and method that can be set in a short time.

  The seismic motion strength measuring device of the present invention uses a structure model equation of motion, a maximum speed response calculating means for calculating a maximum speed response to the acceleration of the ground motion, and an adjustment for determining a natural period of the structure model. A natural period setting means for setting the two natural periods one by one to the maximum speed response calculating means one by one, and a sine wave acceleration value instead of the seismic acceleration at the time of adjustment. The natural period setting means sets the period width of the input sine wave acceleration that satisfies the target accuracy of the SI value, based on the acceleration input means that inputs to the maximum speed response calculated by the maximum speed response calculation means during adjustment. Period width deriving means obtained for each natural period, two natural periods set by the natural period setting means, and an input sine wave obtained by the period width deriving means for each natural period A period width calculation formula deriving unit that obtains a formula indicating the relationship between the period width of the input sine wave acceleration that satisfies the target accuracy of the SI value and the natural period from the cycle width of the speed, and the period width calculation formula deriving unit Using the mathematical formula, the natural period calculating means for calculating the number of natural periods until the natural period exceeds the specified lower limit value and the upper limit value, and the number of terms in the sequence of natural periods is the same as the number of natural periods, A geometric sequence having a natural period is determined so that the first term of the sequence matches the lower limit value and the last term of the sequence matches the upper limit value, and the geometric sequence is set in the maximum speed response calculating means. And natural period correcting means for determining the natural period of the structure model.

In addition, one configuration example of the seismic intensity measurement apparatus of the present invention further includes SI value calculation means for calculating an SI value based on the maximum speed response calculated by the maximum speed response calculation means, and the maximum speed response calculation means. Is characterized in that, at the time of measuring the seismic intensity, a maximum speed response corresponding to the acceleration of the seismic motion is calculated for each natural period set by the natural period correcting means.
Further, in one configuration example of the seismic intensity measuring device of the present invention, the acceleration input means changes the maximum speed while changing the period of the sinusoidal acceleration within a period range corresponding to the natural period set by the natural period setting means. The value of the sine wave acceleration is input to the response calculation means.
Further, in one configuration example of the seismic intensity measuring device of the present invention, the target accuracy of the SI value is the maximum speed obtained when the period of the input sine wave acceleration is equal to the natural period set by the natural period setting means. The period width deriving means defines the range of the period of the input sine wave acceleration in which the normalized value of the maximum speed response is equal to or higher than the target accuracy as SI It is characterized by having a period width that satisfies the target accuracy of the value.
Further, in one configuration example of the seismic intensity measurement device of the present invention, the natural period calculation means, the lower limit value as the first term of the natural period number sequence, until the last term of the natural period number sequence exceeds the upper limit value, The period width of the input sine wave acceleration that satisfies the target accuracy of the SI value is calculated from the current last term of the natural period sequence, and the natural period of the natural period is calculated based on this period width and the current final term of the natural period sequence. By repeating the calculation of a new last term in the sequence, the sequence of natural cycles is obtained, and the number of natural cycles is calculated.
Moreover, in one configuration example of the seismic intensity measurement device of the present invention, one of the two natural periods set by the natural period setting means is the lower limit value, and the other is the upper limit value.

  The seismic intensity measurement method of the present invention also includes a natural period setting step for setting two specified natural periods one by one to the maximum speed response calculating means one by one at the time of adjustment for determining the natural period of the structure model. And an acceleration input step for inputting a value of a sinusoidal acceleration to the maximum speed response calculating means during adjustment, and a first speed response in which the maximum speed response calculating means calculates a maximum speed response using an equation of motion of a structure model during adjustment. Based on the maximum speed response calculation step and the maximum speed response calculated in the first maximum speed response calculation step, the period width of the input sine wave acceleration that satisfies the target accuracy of the SI value is set in the natural period setting step. A period width deriving step determined for each natural period, two natural periods set in the natural period setting step, and the period width deriving step for each natural period A period width calculation formula deriving step for obtaining a mathematical expression indicating the relationship between the period width of the input sine wave acceleration that satisfies the target accuracy of the SI value and the natural period from the obtained cycle width of the input sine wave acceleration, and this period width calculation formula Using the mathematical formula obtained in the derivation step, the natural period calculation step for calculating the number of natural periods from the lower limit value to which the natural period exceeds the upper limit value, and the number of terms in the sequence of natural periods is the natural period The geometric sequence of the natural period is determined so that the first term of the sequence matches the lower limit value, and the last term of the sequence matches the upper limit value, and the geometric sequence is determined as the maximum speed response. And a natural period correcting step for setting the natural period of the structure model by setting in the calculation means.

  According to the present invention, the two specified natural periods are sequentially set to the maximum speed response calculation means one by one, the value of the sine wave acceleration is input to the maximum speed response calculation means, and the maximum speed response calculation means Based on the maximum speed response calculated using the equation of motion of the structure model, the period width of the input sine wave acceleration that satisfies the target accuracy of the SI value is obtained for each natural period set by the natural period setting means, and the natural period is set. From the two natural periods set by the means and the period width of the input sine wave acceleration determined by the period width deriving means for each natural period, the period width and natural period of the input sine wave acceleration satisfying the target accuracy of the SI value, Using this mathematical expression, the number of natural periods from the lower limit value to which the natural period exceeds the upper limit value is calculated, and the number of terms in the natural period sequence is the number of natural periods. Match, first in the sequence The natural period geometric sequence is calculated so that the final term of the sequence matches the upper limit value, and this geometric sequence is set as the maximum speed response calculation means so that the natural period of the structure model By determining the above, it is possible to set a sequence of natural periods that is suitable for the calculation of the SI value and that can suppress the amount of calculation required for the calculation of the SI value in a short time by a method that does not depend on trial and error.

It is a figure which shows one example of the relationship between the period of the sinusoidal acceleration input into a 1 degree-of-freedom 1 mass point attenuation | damping system, and a maximum speed response. It is the figure which described the curve which shows the relationship between the period of the sine wave acceleration input into a 1 degree-of-freedom 1 mass point damping system, and the maximum speed response for every natural period of a 1 degree-of-freedom 1 mass point damping system. It is a block diagram which shows the structure of the seismic-motion intensity | strength measuring apparatus which concerns on embodiment of this invention. It is a flowchart explaining the operation | movement at the time of natural period adjustment of the seismic-motion intensity | strength measuring apparatus which concerns on embodiment of this invention. It is a figure explaining the target accuracy of SI value and the period width of input sine wave acceleration in an embodiment of the invention. It is a flowchart explaining the operation | movement at the time of the seismic intensity measurement of the seismic intensity measuring apparatus which concerns on embodiment of this invention.

[Principle of the Invention]
In the present invention, a sequence of natural periods T for which an SI value that satisfies the target accuracy at the worst is obtained without trial and error can be determined by the following method.
As described above, when calculating the SI value, the structure is mathematically modeled with a one-degree-of-freedom one-mass point damping system, and the velocity response of the structure is obtained using the measured seismic motion as the input acceleration, and the SI value is calculated from this velocity response. Ask. The natural period of ordinary wooden houses and concrete buildings is 0.1 to 2.5 sec. Therefore, a natural period of 0.1 to 2.5 sec is set for the structure model.

  In the present invention, by using such speed response calculation means, sinusoidal accelerations of various periods are inputted to a structure model of a one-degree-of-freedom one-mass point attenuation system having a certain natural period T, and Sv values ( Find the maximum speed response. There is a correlation between the magnitude of the Sv value and the accuracy of the SI value. FIG. 1 is a diagram showing an example of the relationship between the input sine wave acceleration cycle Ts and the Sv value. In the example of FIG. 1, the natural period T = 2.5 sec, the period Ts of the input sine wave acceleration is taken on the horizontal axis, and the normalized value of the Sv value is taken on the vertical axis. The normalized value of the Sv value is 100% of the Sv value when Ts = T = 2.5 sec.

  As shown in FIG. 1, the Sv value is maximized when the input sine wave acceleration period Ts is equal to the natural period T, and decreases when the input sine wave acceleration period Ts departs from the natural period T. The smaller Sv value indicates that the accuracy of the SI value is worsened. Therefore, the period width w of the input sine wave acceleration that can ensure the accuracy of the SI value equal to or higher than the target accuracy is uniquely determined as shown in FIG.

FIG. 2 is a diagram in which a curve showing the relationship between the period Ts of the input sine wave acceleration and the Sv value is described for each natural period T of the one-degree-of-freedom one-mass point damping system. In FIG. 2, for each natural period T from T ₁ = 0.1 sec to T _n = 2.5 sec, curves C ₁ , C ₂ , C ₃ showing the relationship between the period Ts of the input sine wave acceleration and the Sv value. ,..., C _n-2 , C _n-1 , C _n are described. _{w 1, w 2, w 3} , ····, w n-2, w n-1, w n are each natural period _{T 1, T 2, T 3} , ····, T n-2, Regarding T _n-1 and T _n , the period width of the input sine wave acceleration that can ensure the target accuracy of the SI value is shown.

The features understood from FIG. 2 are summarized as follows.
(I) When the natural period T is short, the Sv value decreases in proportion to the natural period T, and when the natural period T is long, the Sv value increases.
(II) When the natural period T is short, the drop in the Sv value when the input sine wave acceleration period Ts deviates from the natural period T (the Sv value changes rapidly with respect to the period Ts), and the natural period T Is longer, the drop in the Sv value when the input sine wave acceleration period Ts deviates from the natural period T becomes smaller.

[Embodiment]
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 3 is a block diagram showing the configuration of the seismic intensity measuring apparatus according to the embodiment of the present invention. The seismic intensity measuring apparatus includes an accelerometer 1 that detects acceleration of seismic motion, an Sv value calculation unit 2 (maximum speed response calculation means) that calculates an Sv value for the acceleration of seismic motion using the motion equation of the structure model, When adjusting the natural period T, the natural period setting unit 3 that sets the two specified natural periods one by one to the Sv value calculation unit 2 in order, and instead of the acceleration of the seismic motion when adjusting the natural period T, Based on the acceleration input unit 4 that inputs the value of the sine wave acceleration to the Sv value calculation unit 2 and the Sv value calculated by the Sv value calculation unit 2, the period width of the input sine wave acceleration that satisfies the target accuracy of the SI value is A period width deriving unit 5 for each natural period set by the natural period setting unit 3, and a period width calculating expression for obtaining a formula indicating the relationship between the period width of the input sine wave acceleration that satisfies the target accuracy of the SI value and the natural period T Part 6 and period width calculation formula The natural period calculation unit 7 for calculating the number of natural periods T from the lower limit value to the upper limit value using the formula obtained by the output unit 6, and the natural period of the structure model by correcting the sequence of the natural periods T The natural period correction unit 8 for determining T, the SI value calculation unit 9 for calculating the SI value based on the Sv value calculated by the Sv value calculation unit 2, and the display unit 10 for displaying the calculation result of the SI value calculation unit 9 And.

Next, the operation | movement at the time of natural period adjustment of the seismic intensity measurement apparatus of this Embodiment is demonstrated using FIG. FIG. 4 is a flowchart for explaining the operation during natural period adjustment.
First, the natural period setting unit 3, defined two natural period T _a of the structure model, with respect to _{T b (T a <T b} ) Sv value calculating section 2 the natural period T _a of one of the Setting is made (step S1 in FIG. 4). In this embodiment, a known lower limit 0.1sec natural period T for obtaining the SI value is T _a.

The acceleration input unit 4 inputs a periodically changing sinusoidal acceleration value to the Sv value calculation unit 2 (step S2 in FIG. 4).
The Sv value calculation unit 2 calculates an Sv value corresponding to the sine wave acceleration input from the acceleration input unit 4 (step S3 in FIG. 4).

When the structure is simplified, the structure is represented by a one-degree-of-freedom one-mass point damping system composed of one weight, a spring, and a damper having a single direction of motion and a single natural period T. The equation of motion of this structure model can be expressed by Equation (1) and Equation (2).
a (t) + 2hωv (t) + ω ² d (t) = − y (t) (1)
ω = 2π / T (2)

y (t) is the input acceleration [cm / sec ² ], a (t) is the acceleration response [Gal], v (t) is the velocity response [cm / sec], d (t) is the displacement response [cm], h Is an attenuation constant. When equation (1) is solved, equation (3) for obtaining the velocity response v (t) with respect to the input of ground acceleration y (t) is obtained.

The Sv value calculation unit 2 calculates the speed response v (t) by substituting the sinusoidal acceleration input from the acceleration input unit 4 as y (t) into equation (3). The Sv value is the maximum absolute value of the speed response v (t) as shown in the following equation.
Sv [cm / sec] = | v (t) | _max (4)

  Thus, the Sv value calculation unit 2 can calculate the Sv value according to the input sine wave acceleration. For the structure model and equations (1) to (4), see the literatures “Hiroyuki Furukawa, Hikaru Takubo, Takashi Hamada, Shunji Ichida, Yoshihisa Shimizu, Kenichi Koganemaru, Wataru Nakayama,“ Intelligent Earthquakes ” Sensor Development, Azbil Corporation, Control Technology Research Report Savemation Review, August 1999 issue ".

After completing the calculation of the Sv value, whether the acceleration input unit 4 has finished inputting the sine wave acceleration in the predetermined period range E _a with respect to the natural period T = T _a = 0.1 sec set by the natural period setting unit 3 determines (Fig. 4 step S4), and if not finished with a sine wave input acceleration, for example, the period of the sine wave acceleration period of the current sine wave acceleration in the range of E _a by adding a predetermined width The value is changed (step S5 in FIG. 4), and the value of the changed sine wave acceleration is input to the Sv value calculation unit 2 (step S2). Thus, until you have calculated Sv values for each sine wave acceleration period range E _a while increasing the period of the sine wave acceleration for example by a predetermined width, the process of step S2~S5 are performed in each cycle of the sine wave acceleration.

After completing the calculation of the Sv value for each sine wave acceleration in the cycle range E _a (YES in step S4 in FIG. 6), the cycle width deriving unit 5 performs the cycle width w _{a of the} input sine wave acceleration that satisfies the target accuracy of the SI value. Is obtained (step S6 in FIG. 4). In the present embodiment, the target accuracy of the SI value is defined by the normalized value of the Sv value when the Sv value obtained when the period of the input sine wave acceleration is equal to the natural period T is 100%. . In the example of the present embodiment, the target accuracy is set to 95%, for example.

Accordingly, the cycle width w _a of the input sine wave acceleration that satisfies the target accuracy is a range of the cycle of the input sine wave acceleration in which the normalized value of the Sv value is equal to or greater than the target accuracy, as shown in FIG. Further, the above-mentioned period range E _a of the input sine wave acceleration is set with a period of 0.1 sec (= T _a ) as the center, includes _a period width w _a assumed in advance, and is sufficiently larger than the period width w _a. It is set to be wide.

After completing the derivation of the period width w _a , the natural period setting unit 3 determines whether or not the period width of the input sine wave acceleration has been derived for the two natural periods T _a and T _b defined in the structure model ( 4, when the period width of the input sine wave acceleration has not been derived, the other natural period T _b of the two natural periods T _a and T _b is set in the Sv value calculation unit 2. (Step S8 in FIG. 4), the process returns to Step S2. In this embodiment, the known upper limit 2.5sec natural period T for obtaining the SI value and T _b. In this way, for the case where the natural period T = T _b = 2.5 sec, the processes of steps S2 to S6 are executed.

However, when the natural period T = T _b = 2.5 sec, the acceleration input unit 4 calculates the Sv value of the sine wave acceleration value in the predetermined period range E _b with respect to the natural period T = T _b = 2.5 sec. Input to the unit 2 (step S2). At this time, the acceleration input unit 4 inputs the value of the sine wave acceleration in the cycle range _Eb to the Sv value calculation unit 2 while increasing the cycle of the sine wave acceleration by, for example, a predetermined width, as described above. Further, the period width deriving unit 5 obtains the period width w _b of the input sine wave acceleration that satisfies the target accuracy of the SI value (step S6).

The definition of the target accuracy of the SI value is as described above. Here, since the natural period T = T _b = 2.5 sec, the target accuracy is that the period of the input sine wave acceleration is the natural period T = T _b = 2.5 sec. Is defined by the normalized value of the Sv value when the Sv value obtained when it is equal to 100% (FIG. 5B). The input sinusoidal acceleration cycle width w _b that satisfies the target accuracy is the range of the input sinusoidal acceleration cycle in which the normalized value of the Sv value is equal to or greater than the target accuracy (95%), as shown in FIG. . The period range E _b of the input sine wave acceleration is set around a period of 2.5 sec (= T _b ), includes a period width w _b assumed in advance, and is sufficiently wider than the period width w _b. Is set.

After deriving the period widths w _a and w _b of the input sine wave acceleration for the two natural periods _Ta and T _b defined in the structure model (YES in step S7), the period width calculation formula deriving unit 6 , the natural period T _a, T _b and period width w _a of the input sine wave acceleration, and a w _b, a formula showing the relationship between the cycle width w and the natural period T of the input sine wave acceleration to meet the target accuracy of the SI value Obtained (step S9 in FIG. 4). For the natural period T, the period width w of the input sine wave acceleration that satisfies the target accuracy of the SI value can be expressed by the following linear expression.
w = αT + β (5)

The coefficients α and β in the equation (5) are obtained as follows by solving simultaneous equations using the natural periods T _a and T _b and the input sinusoidal acceleration period widths w _a and w _b as parameters. be able to.

Next, the natural period calculation unit 7 calculates the number of natural periods T from the natural period T = 0.1 sec to exceeding 2.5 sec using the mathematical formula obtained by the period width calculation formula deriving unit 6 (FIG. 4 step S10). By the processing in step S6, the natural period T = T ₁ = T _a = period width w ₁ = w _a of the input sine wave acceleration to meet the target accuracy of the SI value at 0.1sec are known. The next natural period T ₂ that can ensure the target accuracy of the SI value is based on the period width w ₁ , the natural period T _1, and the period T _m1 of the input sine wave acceleration that is the minimum target accuracy value of the natural period T _2. (8) and (9).

  Substituting equation (1) into equations (8) and (9) and solving, the following equation (10) is obtained.

Therefore, the natural period calculation unit 7 calculates the natural periods T = T ₂ , T ₃ , T ₄ ,... One by one according to the equation (10) until the natural period T to be calculated exceeds 2.5 sec. What is necessary is just to calculate. That is, the natural period calculation unit 7 sets the lower limit value 0.1 sec as the first term T ₁ of the sequence of the natural period T, and the sequence of the natural period T until the last term of the sequence of the natural period T exceeds the upper limit value 2.5 sec. from the current last term T _i, to calculate the period width w _i of the input sine wave acceleration to meet the target accuracy of the SI value, to the current last term T _i of the sequence of the cycle width w _i and the natural period T Based on this, by repeatedly calculating a new final term T _{i + 1} of the number sequence of the natural period T, the number sequence of the natural period T is determined by obtaining the number sequence of the natural period T.

However, at the stage to be calculated natural period T _2, a last term initial term T ₁ is at the same time, since the period width w ₁ = w _a is known, there is no need to re-calculate the period width w _1, cycle width A new final term T ₂ may be calculated using w ₁ and the final term T ₁ .

  In this way, the number n of natural periods T that can ensure the target accuracy of the SI value can be obtained. Table 1 shows an example of the natural period T and the period width w calculated by the natural period calculation unit 7 of the present embodiment. In the example of Table 1, the number of natural periods T is n = 24. Note that the sequence of natural periods T shown in Table 1 is a geometric sequence.

As is clear from Table 1, in the sequence of the natural period T obtained by the natural period calculation unit 7, the natural period T ₁ = 0.1 sec of the _first term matches the known lower limit value 0.1 sec of the natural period T. The natural period T ₂₄ = 2.669327 sec of the last term does not match the known upper limit value 2.5 sec of the natural period T.

  Therefore, the natural period correcting unit 8 matches the number of terms of the natural period T with the number n of the natural periods T, and the first term of the natural period T has a lower limit value 0 in the range in which the natural period T is defined. .1 sec and a geometric sequence with a modified natural period T is determined so that the last term of the sequence of the natural period T matches the upper limit value 2.5 sec of the specified range of the natural period T (see FIG. 4 step S11).

When the number of terms in the geometric sequence of the natural period T is n = 24, the initial term T ₁ is 0.1 sec, and the final term T _n is 2.5 sec, the common ratio r of the geometric sequence is expressed by the following formula ( 11).

Using this common ratio r, each term Ti (here, i = 2, 3, 4,...) Of the geometric sequence of the natural period T can be obtained as shown in Expression (12).
T _i = T ₁ r ^i-1 (12)

The natural period correction unit 8 may calculate the natural periods T = T ₂ , T ₃ , T ₄ ,..., T _n−1 using Expressions (11) and (12). The step size of the geometric sequence of the natural period T at this time is narrower than the step size of the sequence of the natural period T obtained in step S10. Therefore, the accuracy of the SI value that can be secured by the geometric sequence of the natural cycle T calculated by the natural cycle correction unit 8 is equal to or higher than the accuracy of the SI value that can be secured by the sequence of the natural cycle T obtained in step S10. Good results are obtained. Table 2 shows an example of the geometric sequence of the natural period T calculated by the natural period correction unit 8 of the present embodiment.

The natural period correction unit 8 sets the geometric sequence T ₁ , T ₂ , T ₃ ,..., T _n of the calculated natural period T in the Sv value calculation unit 2 as the natural period T of the structure model. (FIG. 4, step S12). Thus, the adjustment operation of the natural period T is completed.

  FIG. 6 is a flowchart for explaining the operation of the seismic intensity measuring device of the present embodiment when measuring seismic intensity. In actual seismic intensity measurement, the accelerometer 1 detects the acceleration of seismic motion (step S20 in FIG. 6).

The Sv value calculation unit 2 calculates an Sv value corresponding to the acceleration of the earthquake motion detected by the accelerometer 1 for each natural period T (step S21 in FIG. 6).
The SI value calculation unit 9 calculates the SI value by the following equation (13) (step S22 in FIG. 6).

That is, the SI value calculation unit 9 may integrate the value Sv (T) calculated by the Sv value calculation unit 2 for each natural period T and divide by 2.4.
The display unit 10 displays the SI value calculated by the SI value calculation unit 9 (step S23 in FIG. 6). In this example, the SI value is displayed as an example of the SI value processing. However, the SI value information calculated by the SI value calculation unit 9 may be transmitted to the outside of the apparatus. Needless to say.

  As described above, according to the present embodiment, a sequence of natural periods T that is suitable for SI value calculation and that can suppress the amount of calculation required for SI value calculation can be obtained in a short time by a method that does not depend on trial and error. Can be set. In order to achieve compactness and noise resistance, in the case of a seismic intensity measuring device that integrates a calculation unit and an accelerometer and is installed outdoors, the power consumption of the product should be as small as possible. However, in the SI calculation of the damage estimation value performed by the calculation unit, the number of calculations per time increases as the accuracy increases, so there is a trade-off relationship between reduction in power consumption and improvement in accuracy.

  Conventionally, as described above, statistical accuracy has been confirmed by simulation calculations using previously recorded seismic waves and some artificially created waveforms. Therefore, although the estimation accuracy of the SI value can be guaranteed in the seismic wave used for the simulation, there is a problem that the accuracy with respect to other seismic waves cannot be guaranteed.

  On the other hand, in this embodiment, it is easy to set a sequence of natural periods T that can suppress the amount of calculation required to calculate the SI value and can secure the target accuracy of the SI value for various seismic waves. Becomes feasible.

  In order to confirm the effect of the present embodiment, Table 3 shows the results of simulation for A, B, and two seismic waves.

  Here, the true value of the SI value calculated using the geometric sequence of the natural period T of n = 7, where the number n of natural periods T is 2401, that is, the SI value obtained in increments of 0.001 seconds is a true value. The relative error with respect to the true value of the SI value calculated using the differential sequence of the natural period T with n = 7 was obtained. As can be seen from Table 3, for both A and B seismic waves, it is better to use the geometric sequence as in the present embodiment than to use the arithmetic sequence of the natural period T as in the prior art. became.

  The seismic intensity measurement apparatus described in the present embodiment can be realized by a computer having a CPU (Central Processing Unit), a storage device, and an interface, and a program for controlling these hardware resources. The CPU executes the processing described in the present embodiment in accordance with a program stored in the storage device.

  The present invention can be applied to a technique for calculating an SI value, which is a kind of estimated earthquake damage value.

  DESCRIPTION OF SYMBOLS 1 ... Accelerometer, 2 ... Sv value calculating part, 3 ... Natural period setting part, 4 ... Acceleration input part, 5 ... Period width derivation part, 6 ... Period width calculation formula derivation part, 7 ... Natural period calculation part, 8 ... Natural period correction unit, 9... SI value calculation unit, 10... Display unit.

Claims (12)

Maximum velocity response calculation means for calculating the maximum velocity response to the acceleration of the ground motion using the equation of motion of the structure model,
A natural period setting means for setting two specified natural periods one by one to the maximum speed response calculating means one by one at the time of adjustment for determining the natural period of the structure model;
Acceleration input means for inputting a value of sinusoidal acceleration to the maximum speed response calculation means instead of the acceleration of seismic motion during adjustment,
Period width deriving means for obtaining the period width of the input sine wave acceleration satisfying the target accuracy of the SI value for each natural period set by the natural period setting means based on the maximum speed response calculated by the maximum speed response calculating means at the time of adjustment When,
The period of the input sine wave acceleration that satisfies the target accuracy of the SI value from the two natural periods set by the natural period setting means and the period width of the input sine wave acceleration determined by the period width deriving means for each natural period. A period width calculation formula deriving means for obtaining a mathematical formula indicating the relationship between the width and the natural period;
Using the mathematical formula obtained by this period width calculation formula deriving means, the natural period calculating means for calculating the number of natural periods until the natural period exceeds the upper limit value from the prescribed lower limit value;
The natural period geometric sequence so that the number of terms in the natural period sequence matches the number of natural periods, the first term in the sequence matches the lower limit value, and the last term in the sequence matches the upper limit value And a natural period correcting means for determining the natural period of the structure model by setting the geometric sequence in the maximum speed response calculating means. In the seismic intensity measuring apparatus according to claim 1,
Furthermore, it comprises SI value calculation means for calculating an SI value based on the maximum speed response calculated by the maximum speed response calculation means,
The maximum velocity response calculation means calculates a maximum velocity response according to the acceleration of the earthquake motion for each natural period set by the natural period correction means when measuring the earthquake intensity. In the seismic intensity measurement apparatus according to claim 1 or 2,
The acceleration input means inputs a sine wave acceleration value to the maximum speed response calculation means while changing a sine wave acceleration period within a period range corresponding to the natural period set by the natural period setting means. Seismic intensity measuring device. In the seismic intensity measurement apparatus according to any one of claims 1 to 3,
The target accuracy of the SI value is the normalized value of the maximum speed response when the maximum speed response obtained when the period of the input sine wave acceleration is equal to the natural period set by the natural period setting means is 100%. Stipulated in
The period width deriving means sets the range of the period of the input sine wave acceleration in which the normalized value of the maximum speed response is equal to or higher than the target accuracy as a cycle width that satisfies the target accuracy of the SI value. . In the seismic intensity measurement apparatus according to any one of claims 1 to 4,
The natural period calculation means uses the lower limit value as the first term of the natural period sequence, and from the current final term of the natural period sequence until the final term of the natural period sequence exceeds the upper limit value, the SI value target By calculating the period width of the input sine wave acceleration satisfying the accuracy, and repeating calculating the new final term of the natural period sequence based on this period width and the current final term of the natural period sequence, A seismic intensity measuring apparatus characterized by obtaining a sequence of natural periods and calculating the number of natural periods. In the seismic intensity measurement apparatus according to any one of claims 1 to 5,
One of the two natural periods set by the natural period setting means is the lower limit value, and the other is the upper limit value. A natural period setting step for setting two specified natural periods one by one to the maximum speed response calculating means one by one at the time of adjustment for determining the natural period of the structure model;
An acceleration input step of inputting a value of a sinusoidal acceleration to the maximum speed response calculating means during adjustment;
A first maximum speed response calculating step in which the maximum speed response calculating means calculates a maximum speed response using an equation of motion of a structure model during adjustment;
Based on the maximum speed response calculated in the first maximum speed response calculation step, the period width of the input sine wave acceleration satisfying the target accuracy of the SI value is obtained for each natural period set in the natural period setting step. Steps,
The period of the input sine wave acceleration that satisfies the target accuracy of the SI value from the two natural periods set in the natural period setting step and the period width of the input sine wave acceleration obtained in the period width deriving step for each natural period. A period width calculation formula deriving step for obtaining a mathematical formula indicating the relationship between the width and the natural period;
Using the mathematical formula obtained in this period width calculation formula derivation step, the natural period calculation step for calculating the number of natural periods until the natural period exceeds the upper limit value from the specified lower limit value,
The natural period geometric sequence so that the number of terms in the natural period sequence matches the number of natural periods, the first term in the sequence matches the lower limit value, and the last term in the sequence matches the upper limit value And a natural period correcting step for determining the natural period of the structure model by setting the geometric sequence in the maximum speed response calculating means. The method for measuring ground motion intensity according to claim 7,
Furthermore, a second maximum speed response calculation step in which the maximum speed response calculation means calculates a maximum speed response according to the acceleration of the earthquake motion for each natural period set in the natural period correction step when measuring the seismic intensity.
A method for measuring seismic intensity, comprising: an SI value calculating step for calculating an SI value based on the maximum speed response calculated in the second maximum speed response calculating step. In the seismic intensity measurement method according to claim 7 or 8,
In the acceleration input step, the value of the sine wave acceleration is input to the maximum speed response calculation means while changing the cycle of the sine wave acceleration within a period range corresponding to the natural period set in the natural period setting step. Seismic intensity measurement method. In the seismic intensity measurement method according to any one of claims 7 to 9,
The target accuracy of the SI value is the normalized value of the maximum speed response when the maximum speed response obtained when the period of the input sine wave acceleration is equal to the natural period set in the natural period setting step is 100%. Stipulated in
The period width deriving step includes setting the period range of the input sine wave acceleration in which the normalized value of the maximum speed response is equal to or higher than the target accuracy as a period width that satisfies the target accuracy of the SI value. . In the seismic intensity measurement method according to any one of claims 7 to 10,
The natural period calculation step uses the lower limit value as the first term of the natural period sequence, and from the current final term of the natural period sequence until the final term of the natural period sequence exceeds the upper limit value, the SI value target By calculating the period width of the input sine wave acceleration satisfying the accuracy, and repeating calculating the new final term of the natural period sequence based on this period width and the current final term of the natural period sequence, A seismic intensity measurement method characterized by calculating a number sequence of natural periods by obtaining a sequence of natural periods. In the seismic intensity measurement method according to any one of claims 7 to 11,
One of the two natural periods set in the natural period setting step is the lower limit value, and the other is the upper limit value.

Images