JP2014102231A - Safety evaluation device in seismic isolation architectural structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safety evaluation device in a seismic isolation architectural structure that can obtain accelerations at two positions on a foundation and in an upper structure with one accelerometer and can accurately evaluate the safety of the seismic isolation architectural structure.SOLUTION: On one of a foundation 5 and an upper structure 6, an accelerometer 8 for detecting the acceleration on the installation side is installed. Non-installation-side behavior estimating means 10A estimates, by calculation, the other acceleration on the basis of the measured value by the accelerometer 8. Safety evaluating means 10B evaluates the safety of a seismic isolation architectural structure 1 on the basis of the acceleration on the installation side detected by the accelerometer 8 and the acceleration on the non-installation side estimated by the non-installation-side behavior estimating means 10A.

Description

  The present invention relates to a safety evaluation device for a base-isolated building that performs a safety evaluation of the base-isolated building after an earthquake.

  Conventionally, there are few monitoring systems for base-isolated buildings, and as a system for safety evaluation of buildings after an earthquake disaster, there are mainly systems that can only present acceleration reduction effects and the like. In addition, in an earthquake-resistant building, there exists a system which analyzes the residual earthquake resistance after an earthquake disaster and evaluates safety (for example, patent document 1). Seismic isolation structure refers to a structure in which seismic force is not transmitted directly to the building by providing a seismic isolation layer. Seismic structure is the structure of the building (columns, beams, etc.) A structure designed to withstand. As a method for calculating the response displacement in the seismic isolation device, a method based on an equivalent linear method has been proposed (for example, Patent Document 4).

JP 2011-95237 A JP 2008-298704 A Japanese Patent No. 4728730 JP 2011-214583 A

Kazu Sakai, Juno Sawada, Kenzo Toki, “Estimation of base-input seismic ground motion by backward calculation in time domain [searched on November 7, 2012]”, Internet <URL: http://library.jsce.or.jp/ jsce / open / 00578/1995 / 23-0177.pdf>

  In a building with a seismic isolation layer, it is necessary to know the acceleration at two locations on the foundation and the superstructure in order to perform an accurate safety assessment after the earthquake. Conventionally, separate accelerometers are installed on the foundation and the upper structure, respectively, and there is a problem that the cost is increased.

  The object of the present invention is to make it possible to know the acceleration at the two locations of the foundation and the superstructure with one accelerometer, and to perform accurate safety evaluation of the seismic isolation building while reducing costs. The object is to provide a safety evaluation device for goods.

The safety evaluation device (1) in the base-isolated building (2) of this invention is
It is a device that evaluates the safety of the base-isolated building (2) with the upper structure (6) installed on the foundation (5) via the base-isolated layer (3),
An accelerometer (8) installed on any one of the foundation (5) or the upper structure (6) and detecting the acceleration of the installation-side vibration body;
Non-installation side behavior estimation means (10A) for estimating the acceleration of the non-installation side vibration body of the accelerometer, which is the other vibration body, from the measurement value of the accelerometer (8),
From the acceleration of the installation-side vibration body detected by the accelerometer (8) and the acceleration of the non-installation-side vibration body estimated by the non-installation-side behavior estimation means (10A), the seismic isolation building ( Safety evaluation means (10B) for evaluating the safety of 2) in accordance with established rules,
With.

According to this configuration, the safety evaluation means (10B) uses the accelerations of both the upper structure (6) and the foundation (5) positioned above and below via the seismic isolation layer (3) for safety evaluation. Accurate safety assessment can be performed. Further, the acceleration detected by the accelerometer (8) installed on any one of the foundation (5) or the upper structure (6) by the non-installation side behavior estimation means (10A). From the above, the acceleration of the other vibration body is estimated, so that the acceleration at the two locations of the foundation (5) and the upper structure (6) can be known with one accelerometer (8). Therefore, the number of accelerometers (8) can be reduced, and the cost can be reduced.
In this way, with one accelerometer (8), it is possible to know the acceleration at the two locations of the foundation (5) and the upper structure (6). An accurate safety assessment can be performed.

In the present invention, the non-installation-side behavior estimation means (10A) is configured to perform the non-installation-side behavior analysis by time history response analysis using the mass of the upper structure (6), the rigidity of the seismic isolation layer (3) and the damping characteristics. It is also possible to estimate the acceleration of the seismic body. Time history response analysis is an analysis method in which the equation of motion is numerically integrated in the time domain.
The mass of the superstructure (6), the rigidity and damping characteristics of the base isolation layer (3) are known at the time of designing the base isolation building (2), etc., and the mass, the rigidity of the base isolation layer (3) and If the damping characteristics are known, the seismic body on the non-installation side of the accelerometer is detected from the detected value of the accelerometer (8) installed on either the foundation (5) or the superstructure (6) by time history response analysis. Can be estimated.
As an example of an estimation method using time history response analysis, a method of estimating foundation input seismic motion when an absolute response acceleration component at a certain point is measured has been proposed (non-patent document). If this estimation method is applied to the seismic isolation building (2), as described above, the seismic body on the non-installation side is determined from the acceleration of the foundation (5) or the upper structure (6) where the accelerometer (8) is installed. Can be estimated.

The estimation of the acceleration / displacement waveform on the foundation (5) side will be described. These are known by checking the characteristics (rigidity, damping) of the base isolation layer (3) and the weight of the superstructure (6) at the time of design. At this time, the input acceleration is estimated by time history response analysis from the properties (weight / rigidity / damping) of the upper structure (6) and the acceleration waveform obtained on the upper structure (6) side.
Specifically, the successive integration is performed in the negative direction of the time axis, and the n + 1 step is known and the n step is unknown. As a result, sequential calculation is performed.
Based on the acceleration waveform obtained above, the displacement waveform on the base (5) side is estimated. A method for estimating the displacement waveform from the acceleration waveform will be described in the section “Description of Embodiments”. The acceleration / displacement waveform difference between the upper structure (6) side and the foundation (5) side is the acceleration reduction effect / response displacement. Moreover, the value of the response displacement after the earthquake motion converges becomes the residual displacement.

  The case where the accelerometer (8) is installed on the foundation (5) side will be described. The displacement waveform of the foundation (5) is obtained by estimating the displacement of the acceleration waveform obtained on the foundation (5) as described above. Further, the acceleration / displacement on the upper structure (6) side is obtained by performing a time history response analysis based on the known acceleration on the base (5) side and the properties on the upper structure (6) side. The response acceleration, displacement, and residual displacement on the body (6) side are obtained.

When the accelerometer (8) is installed in the upper structure (6), more specifically, the non-installation-side behavior estimation means (10A) includes the mass of the upper structure (6), the seismic isolation The acceleration of the foundation (5) may be estimated by time history response analysis by the following equation using the rigidity and damping characteristics of the layer (3).

  The above equation (3) is reassigned to equations (1) and (2) to determine the response vector for the nth step. Thereafter, sequential calculation is performed in the same manner. The relative displacement x is a horizontal relative displacement between the foundation 5 and the upper structure 6. “・” Means time-related differentiation. The subscript of each vector is the number of calculation steps, and the product with Δt represents time. γ and β are arbitrary values as described above, and are appropriately determined according to the results of tests and simulations. By such calculation, the input acceleration to the foundation (5) is estimated from the response acceleration waveform obtained by the accelerometer (8) of the upper structure (6).

Further, when the accelerometer (8) is installed on the foundation (5), the non-installation side behavior estimation means (10A) includes the mass of the upper structure (6) and the rigidity of the seismic isolation layer (3). The acceleration of the upper structure (6) may be estimated by a time history response analysis according to the following equation using the damping characteristics.

In the safety evaluation device (1) for the base-isolated building (2) of the present invention, the safety evaluation means (10B) includes the acceleration detected by the accelerometer (8) and the non-installation side behavior estimation means (10A). ) The base isolation layer (3) calculating the energy absorption amount of the base isolation layer (3) from the acceleration estimated by the above), and the residual energy absorption of the base isolation layer (3) calculated by this means It may be determined whether or not the amount is sufficient for an assumed aftershock, and if it is not sufficient, it may have aftershock response capability determination means for determining that the amount is dangerous.
In this configuration, one of the important factors for accurate safety assessment is to determine the amount of residual energy absorbed by the seismic isolation layer (3) and determine whether it is sufficient for the assumed aftershock. The aftershock response capability can be determined.

In this invention, the safety evaluation means (10B) is configured to respond to the seismic isolation layer (3) from the acceleration detected by the accelerometer (8) or the acceleration estimated by the non-installation side behavior estimation means (10A). Seismic isolation layer response displacement calculating means (22) for determining displacement, and determining whether or not the response displacement calculated by this means (22) is within the design limit. If it is outside the design limit, response displacement safety judgment means (23) for judging that it is dangerous may be included.
In this configuration, the response displacement of the seismic isolation layer (3) is obtained, and it is determined whether the response displacement is within the design limit. It can be determined whether or not the seismic isolation layer (3) has responded beyond the design limit during an earthquake.

In the present invention, the safety evaluation means (10B) compares the natural period of the ground before and after the occurrence of the earthquake from the ground micro vibrations before and after the occurrence of the earthquake measured by the micro vibration measuring means for measuring the micro vibration of the ground, and the comparison result It is good also as having a ground natural period change judging means (18) which judges that it is dangerous when it exceeds this tolerance range compared with the defined ground period change tolerance range.
As a result, safety can be evaluated in consideration of changes in the natural period of the ground necessary for seismic isolation.

  The safety evaluation device for a base-isolated building according to the present invention is a device for evaluating the safety of a base-isolated building in which an upper structure is installed on a foundation via a base isolation layer, the base or the upper An accelerometer that is installed on one of the structural vibration bodies and detects the acceleration of the vibration body on the installation side, and an accelerometer that is the other vibration body from the measured value of this accelerometer Non-installation-side behavior estimation means that estimates the acceleration of the non-installation-side vibration body by calculation, and the acceleration of the installation-side vibration body detected by the accelerometer and the non-installation-side behavior estimation means Since there is a safety evaluation means for evaluating the safety of the base-isolated building from the acceleration of the vibration body on the non-installation side according to a predetermined rule, two locations on the foundation and the upper structure are provided with one accelerometer. Can know the acceleration of the low cost While achieving, perform accurate safety evaluation of seismic isolation buildings.

It is explanatory drawing of the seismic isolation building which applies the safety evaluation apparatus of the seismic isolation building which concerns on one Embodiment of this invention. It is a block diagram of schematic structure of the safety evaluation device. It is a block diagram of other schematic composition of the safety evaluation device. It is explanatory drawing which shows the concept of the estimation process which calculates | requires the other acceleration from one acceleration of the foundation and upper structure in the safety evaluation apparatus. It is a block diagram of the conceptual composition of the safety evaluation device. It is a flowchart which shows the flow of a process of the safety evaluation apparatus at the time of installing an accelerometer in an upper structure. It is a flowchart which shows the flow of a process of the safety evaluation apparatus at the time of installing on the basis of an accelerometer. It is a graph which shows the relationship between a displacement, force, and a seismic isolation force restoring force characteristic. It is explanatory drawing of the Fourier analysis result of the slight vibration of a ground or a building.

  An embodiment of the present invention will be described with reference to the drawings. The building to be evaluated by the safety evaluation device 1 is a base-isolated building 2, that is, a building having a base-isolated layer 3. In the base-isolated building 2, an upper structure 6, which is a main body of the building, is constructed on a foundation 5 on the ground 4 via a base-isolating layer 3. In the illustrated example, the seismic isolation layer 3 is a seismic isolation layer in which a steel ball is interposed between a pair of confronting seat members, such as conical surfaces and spherical surfaces, provided on the foundation 5 and the building 2, respectively. The apparatus 7 is installed at a plurality of locations (for example, 4 locations). In addition to this, the seismic isolation layer 3 can be of various types such as a sliding bearing, an elastic body such as rubber, a damper, and the like. The seismic isolation building 2 only needs to be a building having the seismic isolation layer 3 and has a scale and a structural form such as a general house, an apartment house, an office building, a steel structure, a reinforced concrete structure, a steel reinforced concrete structure, and a wooden structure. It can be applied regardless.

  The ground 4 is generally a layer type in which the surface layer ground 4b is present on the engineering base 4a. In this embodiment, the ground 4 of such a type is applied to the evaluation. The engineering base 4a generally means a ground layer having an N value of 50 or more and a shear wave speed of 400 m / s or more and sufficient rigidity and strength to support a building. The surface layer ground 4b is a layer on the engineering base 4a, and the ground motion transmitted to the engineering base 4a is amplified by the surface base 4b and transmitted to the seismic isolation building 2.

  This seismic isolation building safety evaluation device 1 is a device for evaluating the safety of the seismic isolation building 2 in which the upper structure 6 is installed on the foundation 5 via the seismic isolation layer 3 as described above. An accelerometer 8 installed on any one of the foundation 5 or the upper structure 6 and detecting the acceleration of the installation-side vibration body, and the safety evaluation apparatus shown in FIG. It is comprised with the main body 9. When the accelerometer 8 is installed on the foundation 5 side, the accelerometer 8 is installed on the top edge of the foundation 5 or the soil (not shown), but the accelerometer 8 may be installed on the ground where the foundation 4 is located. When installing the accelerometer 8 on the upper structure 6 side, for example, the accelerometer 8 is installed on the seismic isolation rack 6a (FIG. 1) which is the bottom of the upper structure 6.

  As shown in FIG. 2, the safety evaluation device body 9 includes an evaluation calculation unit 10 and a communication device 31. The accelerometer 8 may be incorporated in the safety evaluation apparatus main body 9, or may be connected to the safety evaluation apparatus main body 9 by wiring or wirelessly as shown in FIG. In any case, the evaluation calculation unit 10 and the communication device 31 are configured by, for example, a personal computer. The communication device 31 is a device that connects the evaluation calculation unit 10 to a server (not shown) in a building manufacturer's office or the like via a wide area computer communication network such as the Internet. The communication device 31 may connect the evaluation calculation unit 10 only to a home display device without using the Internet. Note that the evaluation safety device main body 9 in the figure is merely an example, and various other configurations can be employed.

The evaluation calculation unit 10 includes a memory 10a in a computer, a CPU (central processing unit) 10b, and an evaluation program 10c executed by the CPU 10b. This constitutes the safety evaluation means 10B.
The non-installation side behavior estimation means 10A estimates the acceleration of the vibration body on the non-installation side of the accelerometer which is the other vibration body of the foundation 5 and the upper structure 6 from the measurement value of the accelerometer 8 by calculation. Means.
The safety evaluation means 10B determines the seismic isolation building based on the acceleration of the installation-side vibration body detected by the accelerometer 8 and the acceleration of the non-installation-side vibration body estimated by the non-installation-side behavior estimation means 10A. It is a means for evaluating the safety of the object 1 according to a predetermined rule, and constitutes each function achievement means (11 to 23) which will be described later with reference to FIGS.

  As shown in the conceptual diagram of FIG. 4, the non-installation side behavior estimation means 10 </ b> A includes input acceleration input to the seismic isolation layer 3 due to seismic motion, characteristics (actions and effects) of the seismic isolation layer 3, and the upper structure 6. It is a means for estimating the acceleration of the vibration body on the non-installation side of the accelerometer 8 from the response acceleration or the input acceleration using the relationship between the mass and the response acceleration of the upper structure 6. The characteristics of the base isolation layer 3 are the rigidity and damping characteristics of the base isolation layer. The acceleration of the vibration body on the non-installation side can be estimated by, for example, time history response analysis.

  Time history response analysis is an analysis method in which the equation of motion is numerically integrated in the time domain. The mass of the upper structure 6 and the rigidity and damping characteristics of the seismic isolation layer 3 are known at the time of designing the seismic isolation building 1 and the time history response is obtained if the mass and the rigidity and damping characteristics of the seismic isolation layer are known. By the analysis, the acceleration of the vibration body on the non-installation side of the accelerometer 8 can be estimated from the detection value of the accelerometer installed on either the foundation 5 or the upper structure 6. For example, the input acceleration to the foundation 5 is estimated by time history response analysis from the acceleration waveform obtained by the accelerometer 8 in the upper structure 6. Specifically, the successive integration is performed in the negative direction of the time axis, and the (n + 1) th step is known and the nth step is unknown. As a result, sequential calculation is performed. Based on the acceleration waveform obtained above, the displacement waveform on the foundation 5 side is estimated as in the following equation. The difference in acceleration / displacement waveform between the upper structure 6 side and the foundation 5 side is the acceleration reduction effect / response displacement. Moreover, the value of the response displacement after the earthquake motion converges becomes the residual displacement.

The following expression is an arithmetic expression when the acceleration on the foundation 5 side is estimated by the time history response analysis by the non-installation side behavior estimation means 10A when the accelerometer 8 is installed on the upper structure 6. Equation (3) is reassigned to Equations (1) and (2) to determine the response vector for the nth step. Thereafter, sequential calculation is performed in the same manner.

  The relative displacement x is a horizontal relative displacement between the foundation 5 and the upper structure 6. “・” Means time-related differentiation. The subscript of each vector is the number of calculation steps, and the product with Δt represents time. γ and β are arbitrary values as described above, and are appropriately determined according to the results of tests and simulations. The mass matrix [M] is as follows when the absolute response acceleration is observed in a concentrated three-mass system (mass m1, m2, m3), for example.

  By such calculation, the input acceleration to the foundation 5 is estimated from the response acceleration waveform obtained by the accelerometer 8 of the upper structure 6. After estimating the acceleration, the non-installation side behavior estimation means 10A also calculates the displacement waveform of the non-installation-side seismic body from the estimated acceleration as described later.

  When the accelerometer 8 is installed on the foundation 5, the non-installation-side behavior estimation means 10A uses the mass of the upper structure 6, the rigidity of the seismic isolation layer 3 and the damping characteristics as described above to calculate the time The acceleration of the upper structure 6 is estimated by history response analysis.

  Next, the safety evaluation means 10B shown in FIGS. 2 and 3 will be described with reference to FIGS. For the safety evaluation means 10B shown in FIG. 5, the flow of processing when the accelerometer 8 is installed on the upper structure 6 side is shown in FIG. 6, and the flow of processing when the accelerometer 8 is installed on the foundation 5 side is shown. As shown in FIG. 6 and 7 are the same except that steps S4 and S5 in FIG. 6 are different from steps S4 ′ and S5 ′ in FIG. In these flowcharts, the description “building” means the upper structure 6.

  In FIG. 5, the safety evaluation means 10B includes a constant ground natural period calculation means 11, an earthquake detection means 12, an earthquake acceleration recording means 13, an acceleration waveform analysis calculation means 14, a base isolation layer energy absorption amount calculation means 15, a base isolation determination. Means 16, post-earthquake natural period calculating means 17, post-earthquake natural period change determining means 18, aftershock response capability determining means 19, seismic isolation restoration measurement setting means 20, post-earthquake surface layer amplification factor calculating means 21, seismic isolated layer Response displacement calculating means 22 and response displacement safety determining means 23 are provided.

The configuration and function of each of the means 11 to 23 will be described with reference to the flowcharts of FIGS.
Normal natural period calculating means 11: The seismic isolated building safety evaluation apparatus 1 first measures the slight vibration of the ground 4 during normal times (step S1). This measurement is performed, for example, using a portable accelerometer (not shown) temporarily installed on the foundation 5 or the ground 4 on which the foundation 5 is located. The accelerometer 8 is installed on the foundation 5. In that case, the accelerometer 8 may be used. From this measurement result, a normal soil natural period Tg and a building natural period T are calculated (S2). Each natural period calculation means 11 normally performs these steps S1 and S2. The processes of steps S1 and S2 may be performed only once at the time of designing or constructing the building 3, or may be repeated after the construction until the occurrence of the earthquake.
In addition, the frequency f which shows a peak can be confirmed as shown in FIG. 9 by measuring the fine vibration of a ground and performing a Fourier analysis. This reciprocal, 1 / f, is the ground natural period Tg. That is, Tg = 1 / f. Each natural period calculation means 11 in normal times calculates the ground natural period Tg from the normal ground vibration as described above. The post-earthquake natural period calculating means 17 described later also calculates each natural period by Fourier analysis in the same manner as described above.

  Earthquake detection means 12: Detects that an earthquake has occurred (S3). The detection of the occurrence of an earthquake may be performed using the detection value of the accelerometer 8, or may be performed using a seismometer different from this. The earthquake detection means 12 performs the process of step S3.

  Earthquake acceleration recording means 13: The acceleration measured by the accelerometer 8 at the time of an earthquake by detecting the occurrence of an earthquake by the earthquake detection means 12 is recorded in a predetermined storage area of the memory 10a (FIGS. 2 and 3) (S4). , S4 ′). When the accelerometer 8 is installed on the upper structure 6, the acceleration waveform of the upper structure 6 is recorded (S5). When the accelerometer 8 is installed on the foundation 5, the acceleration waveform of the foundation 5 is recorded. Record (S5 '). The earthquake acceleration recording means 13 performs the processes of steps S4 and S4 '.

Acceleration waveform analysis calculation means 14: When the accelerometer 8 is installed in the upper structure 6, the following items are analytically calculated from the acceleration waveform on the upper structure 6 side as shown in FIG. . That means
-Calculation of displacement waveform of upper structure 6 (building side) (S5a),
・ Calculation of acceleration and displacement waveform on the foundation 5 side (S5b),
・ Calculation of residual displacement of seismic isolation layer 3 (S5c),
I do.
The acceleration waveform analysis calculation means 14 includes an installation side displacement waveform calculation unit 14a, a non-installation side behavior estimation means use unit 14b, and a seismic isolation layer residual displacement calculation unit 14c. These units 14a, 14b, 14c Steps S5a, S5b, and S5c are performed. Specifically, the non-installation-side behavior estimation unit using unit 14b causes the non-installation-side acceleration estimation unit 10A to calculate the acceleration on the foundation 5 side and the displacement waveform.

When the accelerometer 8 is installed on the foundation 5, as shown in FIG. 7, the following items are calculated analytically from the acceleration waveform on the foundation 5 side. That means
・ Calculation of displacement waveform on the foundation 5 side (S5a ′),
・ Calculation of acceleration on the building (upper structure 6) side and displacement waveform (S5b '),
・ Calculation of residual displacement of seismic isolation layer 3 (S5c '),
I do.
When the accelerometer 8 is installed on the foundation 5, the installation-side displacement waveform calculation unit 14a, the non-installation-side behavior estimation unit use unit 14b, and the seismic isolation layer residual displacement calculation unit 14c of the acceleration waveform analysis calculation unit 14 are: Each of the steps S5a ', S5b' and S5c 'is performed. Specifically, the non-installation-side behavior estimation unit using unit 14b ′ causes the non-installation-side acceleration estimation means 10A to calculate the acceleration and displacement waveform on the upper structure 6 side.

To estimate the displacement waveform from the acceleration waveform, one of the following methods is employed. You may consider 0 axis correction and a frequency filter suitably.
Direct integration method (method of calculating displacement by second-order integration of acceleration changes at times t and t + 1)
・ 10-second pendulum method (estimation method in which an observed acceleration waveform is input to a vibration system with a natural period of 10 seconds and a damping constant of 1 / √2, and the response displacement becomes a displacement waveform)
-Trifunac method (0-axis correction, low-pass, high-pass filter combined frequency integration method)
The residual displacement δz of the seismic isolation layer 3 is a value obtained by subtracting the displacement of the foundation 5 from the displacement of the building (upper structure 6).

  Seismic isolation layer energy absorption amount calculation means 15: After steps S5 and S5 ', the residual energy absorption amount that can be absorbed by the base isolation layer 3 is calculated from the residual displacement δz calculated by the residual displacement calculation unit 14c (S6). ). The seismic isolation layer energy absorption amount calculation means 15 performs the process of step S6.

Seismic isolation determining means 16: After calculating the seismic isolation layer energy absorption (S6), it is determined whether or not the base has been normally isolated (S7). In this example, normal isolation means that the response acceleration is within the expected range (that is, within the specified allowable range), and the response acceleration history is not disturbed (that is, within the specified change in allowable history). And the response displacement is within the design limit (within the set allowable displacement). If any one of these conditions is not satisfied, it is determined as dangerous (S16).
Note that the determination in step S7 is a test based on the already observed acceleration data, and step S14 described later confirms whether the response displacement is within the design limit displacement during the next earthquake motion.

  Post-earthquake natural period calculation means 17: After the occurrence of the earthquake, the ground microtremor Tg 'is measured, and the natural period of the ground is calculated from the measurement result (S8). In this case, the ground micro-vibration Tg ′ is also measured temporarily by a portable accelerometer (not shown) installed on the foundation 5 or the ground 4 on which the foundation 5 is located. When 8 is installed, the accelerometer 8 may be used. The post-earthquake ground natural period calculating means 17 performs the vibration measurement and the calculation of the ground natural period.

  Ground natural period change judging means 18: After step S8, the natural period Tg ′ after the earthquake is not significantly larger than the normal natural period Tg of the ground, that is, exceeds the allowable period variation range. It is determined whether there is any (S9). If it is significantly larger, it is determined as dangerous (S18). The ground natural period change determining means 18 determines whether or not the above is significantly large.

  Aftershock response capability determination means 19: After step S9, it is determined whether the residual energy absorption amount of the seismic isolation layer 3 calculated in step S6 is sufficient for the assumed aftershock (S10). The assumed aftershock is, for example, the maximum aftershock of the ratio determined according to the main shock recorded by the earthquake acceleration recording means 13 (S4, S4 '), etc., and converted into the amount of energy borne by the seismic isolation layer 3 To do. Whether or not it is sufficient for the assumed aftershock is determined by the difference in energy amount or the ratio of the energy amount set as sufficient. If the above determination (S10) is not sufficient, the process proceeds to step S16, where it is determined to be dangerous (S16). If it is sufficient, the process proceeds to the next step (S11), and after determining from another viewpoint, it is determined whether or not it is safe. The aftershock response capability determination means 19 performs the process of step S10.

Seismic isolation layer restoring force characteristic setting means 20: Calculates the seismic isolation restoring force characteristic K ′ from the earthquake acceleration recorded by the earthquake acceleration recording means 13 and the residual displacement of the seismic isolation layer 3, and will be described later. It resets to the layer response displacement calculation means 22 (S11). The seismic isolation layer restoring force characteristic setting means 20 performs the process of step S3.
Explaining an example of how to obtain the seismic isolation force restoring force characteristic K ′, FIG. 8 is obtained from the data (acceleration, displacement, building weight (value calculated at the time of building design)) at the time of the earthquake. From the figure, seismic isolation force restoring force characteristics K1, K2 and Q are read. In the figure, the horizontal axis represents displacement, and the vertical axis represents force.
K1: Primary period of the seismic isolation layer
K2: Secondary period of seismic isolation layer
Q: Section of the base isolation layer (load when the base isolation layer starts moving)
In addition, the relationship between the seismic isolation force restoring force characteristic K ′ and K1, K2 is explained as follows:
K '= Q / θ + K2
It is. K1 and K2 are basically calculated using K2, and K1 is used instead of K2 in the above equation (K ′ = Q / θ + K2) only in the time history response analysis.

Post-earthquake surface ground gain calculation means 21: After step S11, the ground base amplification period Gg calculated by the post-earthquake ground natural period calculation means 17 is calculated from the engineering foundation (G '). S12). The post-earthquake surface layer amplification factor calculation means 21 performs the process of step S12.
A method for obtaining the amplification factor G ′ from the ground natural period Tg ′ is very simple and an example is as follows: G ′ = aTg ′ + b
a: Coefficient b: Calculated from the relationship of constants. The values of a and b are appropriately determined based on experience values.
However, the amplification factor G ′ can be obtained by the ground natural period Tg ′ by various methods without being limited to the above relational expression.

  Seismic isolation layer response displacement calculation means 22: surface displacement ground 4b from the residual displacement δ of the seismic isolation layer 3, the seismic isolation force restoring force characteristic K, and the engineering base 4a in the design of the base isolation building 2 or in normal times Based on the amplification factor G, the response displacement of the seismic isolation layer 3 is calculated by a predetermined calculation method. “Response” refers to a phenomenon in which a building vibrates in response to an external stimulus such as an earthquake or strong wind. After the earthquake, as the procedure of step S13, the residual displacement δ, the seismic isolation force restoring force characteristic K, and the amplification factor G of the ground layer are set as the residual displacement δ ′ after the earthquake, the seismic isolation restoring force characteristic K ′, and Recalculate by resetting to the surface layer amplification factor G ′. The seismic isolation layer response displacement calculation means 22 calculates the response displacement in the process of step S13 and in the design of the building 3 or in normal times. The equivalent linearization method or time history response analysis is used to calculate the seismic isolation layer response displacement. The residual displacement δ is calculated as zero during design and normal times.

  Response displacement safety determination means 23: It is determined whether or not the response displacement calculated in step S13 is within the design limit (S14). If it is within the design limit, the process proceeds to step S15 and is determined to be safe. If it is within the design limit, the process proceeds to step S16 and is determined to be dangerous. The response displacement safety determination means 22 performs the processes of steps S14, S15, and S16.

  The determination result of the safety determination by the evaluation calculation unit 10 is sent to the server via the communication device 31 (FIG. 2).

According to this configuration, since the safety evaluation means 10B uses the accelerations of both the upper structure 6 and the foundation 5 positioned above and below the base isolation layer 3 for safety evaluation, accurate safety evaluation can be performed. Further, from the acceleration detected by the non-installation side behavior estimation means 10A by the accelerometer 8 installed in one of the foundation 5 or the vibration body that is the upper structure 6, the acceleration of the other vibration body is detected. Therefore, it is possible to know the acceleration at two locations on the base 5 and the upper structure 6 with one accelerometer 8. Therefore, the number of accelerometers can be reduced and the cost can be reduced.
As described above, the acceleration of the two locations of the base 5 and the upper structure 6 can be known with one accelerometer 8, and accurate safety evaluation of the base-isolated building 1 can be performed while reducing the cost. .

  The non-installation-side behavior estimation means 10A estimates the acceleration of the non-installation-side vibration body by time history response analysis using the mass of the upper structure 6, the rigidity of the seismic isolation layer 3, and the damping characteristics. From the detection value of the accelerometer 8 installed on either the foundation 5 or the upper structure 6, the acceleration of the vibration body on the non-installation side of the accelerometer 8 can be accurately estimated.

The safety evaluation means 10B calculates an energy absorption amount of the seismic isolation layer 3 from the acceleration detected by the accelerometer 8 and the acceleration estimated by the non-installation side behavior estimation means 10A. Aftershock that determines whether the amount of residual energy absorption of the amount calculation means 15 and the seismic isolation layer 3 calculated by this means 15 is sufficient for the assumed aftershock, and if it is not enough Corresponding capability judging means 19.
In this way, the amount of residual energy absorbed by the seismic isolation layer 3 is obtained, and it is determined whether it is sufficient for the assumed aftershock, so that the aftershock is one of the important factors for accurate safety evaluation The response ability can be determined.

The safety evaluation unit 10B includes a base isolation layer response displacement calculation unit 22 that calculates a response displacement of the base isolation layer 3 from the acceleration detected by the accelerometer 8 or the acceleration estimated by the non-installation side behavior estimation unit 10A. Then, it is determined whether or not the response displacement calculated by the means 22 is within the design limit. If the response displacement is within the design limit, it is determined to be safe, and if it is within the design limit, the response displacement safety determination means 23 is determined to be dangerous. And have.
Thus, in order to obtain the response displacement of the seismic isolation layer 3 and determine whether or not the response displacement is within the design limit, the earthquake is another important factor for the accurate evaluation of safety. Sometimes it can be determined whether the seismic isolation layer has responded beyond design limits.

Furthermore, the safety evaluation means 10B compares the natural period of the ground before and after the occurrence of the earthquake, and the comparison result is determined from the fine vibration of the ground before and after the occurrence of the earthquake measured by the fine vibration measuring means for measuring the fine vibration of the ground. A ground natural period change determining means 18 is provided that determines that the ground period change allowable range is dangerous when the allowable range exceeds the allowable range.
Therefore, safety can be evaluated in consideration of changes in the natural period of the ground necessary for seismic isolation.

DESCRIPTION OF SYMBOLS 1 ... Safety evaluation apparatus 2 ... Seismic isolation building 3 ... Seismic isolation layer 4 ... Ground 4a ... Engineering base 4b ... Surface ground 5 ... Foundation (vibration body)
6 ... Superstructure (vibrating body)
DESCRIPTION OF SYMBOLS 8 ... Accelerometer 10 ... Evaluation operation part 10A ... Non-installation side acceleration estimation means 10B ... Safety evaluation means 11 ... Constant ground natural period calculation means 12 ... Earthquake detection means 13 ... Earthquake acceleration recording means 14 ... Acceleration waveform calculation means 15 ... Seismic isolation layer energy absorption amount calculation means 16 ... base isolation determination means 17 ... post-earthquake ground natural period calculation means 18 ... post-earthquake ground natural period change determination means 19 ... aftershock response capability determination means 20 ... base isolation layer restoring force characteristic setting means 21 ... Post-earthquake surface layer gain calculation means 22 ... Seismic isolation layer response displacement calculation means 23 ... Response displacement safety judgment means

Claims (7)

A device that evaluates the safety of a base-isolated building with an upper structure installed on the foundation via a base isolation layer,
An accelerometer that is installed on any one of the foundation or superstructure seismic bodies and detects the acceleration of the seismic body on the installation side;
From the measured value of this accelerometer, non-installation side behavior estimation means for estimating the acceleration of the non-installation side vibration body of the accelerometer that is the other vibration body,
The safety of the base-isolated building was determined from the acceleration of the installation-side vibration body detected by the accelerometer and the acceleration of the non-installation-side vibration body estimated by the non-installation side behavior estimation means. Safety assessment means to assess according to the rules,
The safety evaluation apparatus in a base-isolated building characterized by comprising.   The safety evaluation apparatus for a base-isolated building according to claim 1, wherein the non-installation-side behavior estimation means uses time history response analysis using a mass of the upper structure, rigidity of the base isolation layer, and damping characteristics. A safety evaluation apparatus for a base-isolated building that estimates the acceleration of a non-installed seismic body. 3. The safety evaluation apparatus for a seismic isolation building according to claim 2, wherein the accelerometer is installed in the upper structure, and the non-installation side behavior estimation means includes a mass of the upper structure, the seismic isolation layer A safety evaluation apparatus for a base-isolated building that estimates the acceleration of the foundation by a time history response analysis according to the following equation using rigidity and damping characteristics.

The safety evaluation apparatus for a seismic isolation building according to claim 2, wherein the accelerometer is installed on the foundation, and the non-installation side behavior estimation means includes the mass of the upper structure, the rigidity of the seismic isolation layer, and A safety evaluation apparatus for a base-isolated building that estimates the acceleration of the upper structure by a time history response analysis according to the following equation using damping characteristics.

  The safety evaluation apparatus for a base-isolated building according to any one of claims 1 to 4, wherein the safety evaluation means includes acceleration detected by the accelerometer and the non-installation side behavior estimation means. The seismic isolation layer energy absorption amount calculating means for calculating the residual energy absorption amount of the base isolation layer from the acceleration estimated by the above, and the residual energy absorption amount of the base isolation layer calculated by this means for the assumed aftershock A safety evaluation device for a base-isolated building, having aftershock response capability determining means for determining whether or not it is sufficient, and determining that it is dangerous if not sufficient.   The safety evaluation apparatus for a base-isolated building according to any one of claims 1 to 5, wherein the safety evaluation unit is an acceleration detected by the accelerometer or the non-installation side behavior estimation unit. The base-isolated layer response displacement calculating means for obtaining the response displacement of the base-isolated layer from the acceleration estimated by the above, and determining whether the response displacement calculated by this means is within the design limit. Is a safety evaluation device for a base-isolated building, which has a response displacement safety determination means for determining safety as being safe and determining that it is dangerous if it is outside the design limit.   The safety evaluation apparatus for a base-isolated building according to any one of claims 1 to 6, wherein the safety evaluation unit is an occurrence of an earthquake measured by a microvibration measuring unit that measures ground microvibration. The natural period of the ground before and after the earthquake is compared with the ground micro-vibration before and after the earthquake, and the comparison result is compared with the allowable ground period change allowable range. Safety evaluation device for base-isolated buildings having means.

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