JP2013170955A - Safety evaluation system for base isolated building - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a safety evaluation system for a base isolated building, capable of performing suitable safety evaluation considering changes in a building and ground property characteristics after a seismic disaster in the base isolated building.SOLUTION: Acceleration sensors are attached to ground 4 and a building 2. Usual microvibration values of the ground 4 and the building 2 before and after an earthquake and acceleration values during the earthquake are measured, and a base isolation strength restoration characteristic K' and residual displacement δ' of a base isolation layer are found out. Further, an amplification rate G' of surface ground is found out. These values K', δ', G' are reset and base isolation layer response displacement after the earthquake is calculated. Whether the base isolation response displacement is included within a design limit or not is determined to perform safety determination. A residual energy absorption amount of the base isolation layer is calculated from the residual displacement δ' and whether residual energy absorption capacity for an aftershock exists or not is determined.

Description

  The present invention relates to a safety evaluation system for a base-isolated building that takes into account changes in building / ground properties 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

  In the case of a base-isolated building, when only the acceleration reduction effect is presented as in the past, the safety cannot be clearly evaluated. In the case of the proposed system for earthquake-resistant buildings, changes in the ground are not taken into account, so long periods of ground motion and residual distortion due to ground loosening, which are a concern in seismic isolation structures, are not taken into account. The sex cannot be confirmed.

  An object of the present invention is to provide a safety evaluation system for a base-isolated building that can perform an appropriate safety evaluation in consideration of changes in the characteristics of the building and the ground properties after the earthquake.

The seismic isolation building safety evaluation system (1) of the present invention is a seismic isolation building safety evaluation system that evaluates safety after an earthquake in a building (2) having a seismic isolation layer (3). , An accelerometer (8a, 8b) provided on the ground (4) where the building (2) is located and the building (2), respectively, and an evaluation calculation unit (10).
The evaluation calculation unit (10) includes normal natural period calculating means (11) (S1, S2), acceleration recording means during earthquake (13) (S4), post natural earthquake natural period calculating means (14) (S5, S5). S6), building natural period change judging means (15) (S7), earthquake displacement history / residual displacement calculating means (16) (S8), base isolation force restoring force characteristic setting means (19) (S11), post-earthquake surface layer Ground amplification factor calculation means (20) (S11), base isolation layer response displacement calculation means (21) (S13), and response displacement safety judgment means (22) (S14).

Each natural period calculating means (11) (S1, S2) at normal times measures the normal vibrations of the ground and buildings at normal times by the respective accelerometers, and calculates the normal natural period Tg and the natural period T of buildings at normal times. To do.
The earthquake acceleration recording means (13) (S4) records the acceleration measured by the respective accelerometers (8a, 8b) at the time of the earthquake due to the occurrence of the earthquake.
After the earthquake, each natural period calculating means (14) (S5, S6) measures the micro vibrations of the ground and the building by each of the accelerometers (8a, 8b) after the occurrence of the earthquake, and then the natural period Tg ′ after the earthquake. And the building natural period T ′ is calculated.

  The building natural period change determining means (15) (S7) determines whether the change of the building natural period T 'after the earthquake with respect to the normal building natural period T is within the allowable range. If not, it is judged as dangerous.

The earthquake displacement history / residual displacement calculating means (16) (S8) is adapted to obtain the earthquake displacement history and residual of the seismic isolation layer from the accelerations recorded during the earthquake recorded by the earthquake acceleration recording means (13) (S4). The displacement δ ′ is calculated.
The seismic isolation force restoring force characteristic setting means (19) (S11) includes the earthquake acceleration recorded by the earthquake acceleration recording means (13) (S4), and the earthquake displacement history / residual displacement calculation means (16). Based on the earthquake displacement history of the base isolation layer calculated in (S8), the base isolation force restoring force characteristic K ′ is calculated and set.

  The post-earthquake surface layer amplification factor calculation means (20) (S11) is supplied from the engineering foundation (4a) by the natural period Tg ′ calculated by the natural period calculation means (14) (S5, S6) after the earthquake. The amplification factor G ′ of the surface ground (4b) is calculated.

The seismic isolation layer response displacement calculating means (21) (S13) is based on the residual displacement δ ′ after the earthquake calculated by the above means, the seismic isolation force restoring force characteristic K ′, and the surface ground amplification factor G ′. The response displacement of the seismic isolation layer (3) after the earthquake is calculated by the prescribed calculation method. As the calculation method defined above, for example, a method of calculating a response displacement using an equivalent linearization method or a time history response analysis can be employed.
The response displacement safety determination means (22) (S14) determines whether or not the response displacement calculated by the seismic isolation layer response displacement calculation means (21) (S13) is within the design limit. Is judged safe, and if it is within the design limits, it is judged dangerous.

According to the safety evaluation system for base-isolated buildings of this configuration, the residual displacement δ ′ after the earthquake, the base-isolation force restoring force characteristic K ′, and the surface ground amplification factor G ′ are obtained, and based on these, the post-earthquake isolation The response displacement of the seismic layer (3) is calculated. The obtained response displacement is compared with the design limit to determine whether it is safe.
In this way, in the base-isolated building, considering the changes in the properties of the building (including the base-isolated layer) and the ground, the building and ground conditions are set, and the analysis is performed based on this. The safety can be determined accordingly. Therefore, appropriate safety evaluation can be performed.
The building natural period change determining means (15) (S7) determines whether the change of the building natural period T 'after the earthquake with respect to the normal building natural period T is within the allowable range. If not, it is judged as dangerous. Therefore, when it is clearly seen as dangerous by looking at the change in the natural period of the building, it can be determined as dangerous without performing various calculations for the ground.

In the present invention, the seismic isolation layer response displacement calculating means (21) (S13) is configured so that the residual displacement δ of the seismic isolation layer (3) in the design of the building (2) or during normal times, the seismic isolation Based on the seismic isolation force characteristic K of the layer (3) and the amplification factor G of the surface ground (4b) from the engineering base (4a), the response displacement of the seismic isolation layer is calculated by a predetermined calculation method. The residual displacement δ, the seismic isolation force restoring force characteristic K, and the surface ground amplification factor G, and the post-earthquake residual displacement δ ′, the seismic isolation force restoring force property K ′, and the surface layer ground amplification factor G. It may be reset to ′ and recalculated.
That is, as the seismic isolation layer response displacement calculation means (21) (S13), a means for calculating the response displacement at the time of design or the like is used, and this includes the surface layer ground amplification factor G ′, residual displacement δ ′, Safety judgment by response displacement can be performed by resetting the seismic force restoring force characteristic K ′. For this reason, safety determination based on response displacement can be performed without providing a dedicated seismic isolation layer response displacement calculation means for post-earthquake use. Since the same seismic isolation layer response displacement calculation means (21) calculates during normal times and after an earthquake, uniform and reliable safety judgment can be performed. The residual displacement δ ′ is calculated as zero at the time of design and normal times.

In this invention, when it is determined by the building natural period change determining means (15) (S7) that it is within an allowable range, it is calculated by the earthquake displacement history / residual displacement calculating means (16) (S8). Seismic isolation layer energy absorption amount calculating means (17) (S9) for calculating a residual energy absorption amount that can be absorbed by the base isolation layer (3) from the residual displacement δ ';
It is determined whether or not the residual energy absorption amount of the seismic isolation layer (3) calculated in this means (17) (S9) is sufficient for the assumed aftershock, and if it is not sufficient, it is determined to be dangerous. Aftershock response capability determination means (18) (S10) may be provided.
Thus, the safety | security with respect to an aftershock can be determined by calculating | requiring the residual energy absorption amount of a seismic isolation layer (3).

  The seismic isolation building safety evaluation system according to the present invention is a seismic isolation building safety evaluation system for evaluating the safety after an earthquake occurs in a building having a seismic isolation layer, and the ground or ground on which the building is located. An accelerometer provided in each of the corresponding parts and the building, and an evaluation calculation unit, and the evaluation calculation unit measures the normal vibration of the ground and the building with each accelerometer, Each natural period calculating means for calculating the natural period Tg and the natural period T of the building, the earthquake acceleration recording means for recording the acceleration measured by each accelerometer at the time of the earthquake, and the occurrence of the earthquake Each post-earthquake natural period calculating means for calculating the ground natural period Tg ′ and the building natural period T ′ after the earthquake by measuring the ground and building micro-vibration by the respective accelerometers, It is determined whether or not the change of the period T ′ with respect to the natural period T of the building is within an allowable range, and if it is not within the allowable range, the natural period change determining means for determining the danger, and the acceleration during the earthquake Earthquake displacement history / residual displacement calculating means for calculating the displacement history and residual displacement δ ′ of the seismic isolation layer from the accelerations recorded by the recording means and the earthquake recorded by the earthquake acceleration recording means Seismic isolation force restoring force characteristic setting that calculates and sets the seismic isolation force restoring force characteristic K ′ from the earthquake acceleration displacement and the earthquake displacement history of the seismic isolation layer calculated by the earthquake displacement history / residual displacement calculating means. A post-earthquake surface ground amplification factor calculating means for calculating an amplification factor G ′ of the surface ground from the engineering base based on the natural ground period Tg ′ calculated by each natural period calculating unit after the earthquake; Calculated residue after earthquake A base isolation layer response displacement calculating means for calculating a response displacement of the base isolation layer after the earthquake by a predetermined calculation method based on the displacement δ ′, the base isolation force restoring characteristic K ′, and the surface ground amplification factor G ′; Determining whether or not the response displacement calculated by this means is within the design limit; if the response displacement is within the design limit, determine that it is safe; Therefore, it is possible to perform an appropriate safety evaluation in a base-isolated building in consideration of changes in buildings and ground properties after an earthquake.

It is explanatory drawing of the seismic isolation building which applies the safety evaluation system of the seismic isolation building which concerns on one Embodiment of this invention. It is a block diagram of a schematic structure of the safety evaluation system. It is a flowchart which shows the flow of a process of the safety evaluation system. It is a block diagram which shows the conceptual structure of the safety evaluation system. 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 system 1 is a base-isolated building, that is, a building 2 having a base-isolated layer 3. In this building 2, a building body 6 is constructed on a foundation 5 on the ground 4 via a seismic isolation layer 3. In the illustrated example, the seismic isolation layer 3 includes a steel ball 7 between a pair of confronting seat members (not shown) such as conical surfaces and spherical surfaces provided on the foundation 5 and the building 2 respectively. The seismic isolation devices intervened in are installed at multiple 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 building 2 only needs to be a building having the seismic isolation layer 3, regardless of the scale or the structure type, such as ordinary houses, apartment houses, office buildings, steel structures, reinforced concrete structures, steel reinforced concrete structures, and wooden structures. Applicable to.

  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 earthquake motion transmitted to the engineering base 4a is amplified by the surface layer ground 4b and transmitted to the building 2.

  This seismic isolation building safety evaluation system 1 includes a ground 4 or a ground-equivalent portion where the building 2 is located, and accelerometers 8a and 8b provided in the building 2, respectively, and an evaluation calculation unit 10 (FIG. 2). Consists of. The accelerometer 8b on the building 2 side is installed on the base isolation frame 6a which is the bottom of the building body 6. The “ground equivalent part” is a part closer to the ground 4 than the seismic isolation layer 3, and the ground-side accelerometer 8 a is equivalent to the ground such as the top of the foundation 5 or the top of the soil (not shown). Installed in the part.

As shown in FIG. 2, the evaluation calculation unit 10 constitutes the evaluation safety system main body 9 together with the building-side accelerometer 8 b and the communication device 31. The evaluation calculation unit 10 and the communication device 8 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. In addition, the evaluation safety system main body 9 of the figure is an example, and can have various other configurations.
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, and constitutes each function achievement means (11-22) shown in FIG. .

  FIG. 3 shows steps (S1) to (S16) of each procedure of the evaluation program 10c. Each function achievement means (11-22) of the evaluation calculation part 10 is comprised by these each procedures and the hardware of a computer (an operation program is included). Steps S1 to S14 in FIG. 3 are denoted by the corresponding function achievement means in FIG.

  As shown in FIG. 3 and FIG. 4, the evaluation calculation unit 10 normally includes each natural period calculating means 11, earthquake detecting means 12, earthquake acceleration recording means 13, each natural period calculating means 14 after an earthquake, building natural period. Change determining means 15, earthquake displacement history / residual displacement calculating means 16, seismic isolation layer energy absorption calculating means 17, aftershock response capability determining means 18, seismic isolation restoring force characteristic setting means 19, post-earthquake surface layer ground gain calculation Means 20, seismic isolation layer response displacement calculation means 21, and response displacement safety judgment means 22 are provided.

The configuration and function of each of the means 11 to 22 will be described with reference to the flowchart of FIG.
Normal natural period calculation means 11: This seismic isolated building safety evaluation system first measures the micro vibrations of the ground 4 and the building 3 at normal times by the respective accelerometers 8a and 8b (step S1). 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. 6 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. The building natural period T is also obtained from the slight vibration as in the case of the ground. Each normal period natural period calculation means 11 calculates the natural period Tg and the natural period T of the building from each normal vibration as described above. Each post-earthquake natural period calculation means 14 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 detected values of the accelerometers 8a and 8b, 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 each of the accelerometers 8a and 8b 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 10b (FIG. 2) (S4). ). The earthquake acceleration recording means 13 performs the process of step S4.

  Each natural period calculation means 14 after the earthquake: After the occurrence of the earthquake, the fine vibrations of the ground 4 and the building 3 are measured by the respective accelerometers 8a and 8b (S5). From the measured values, the natural period Tg ′ after the earthquake and the natural period T ′ of the building are calculated (S6). Since the minute vibration increases in each natural period, the ground natural period Tg ′ and the building natural period T ′ can be obtained from the change in the magnitude and direction of the acceleration included in the fine vibration. Each post-earthquake natural period calculating means 14 performs the processes of steps S5 and S6.

  Building natural period change determining means 15: It is determined whether the change of the building natural period T ′ after the earthquake with respect to the normal building natural period T is within an allowable range (S7). The allowable range is set arbitrarily. If it is determined that the value is within the allowable range, the process proceeds to step S8, and safety determination is performed through the subsequent steps. The building natural period change determining means 15 performs the processes of steps S7, S15, and S16.

Seismic displacement history / residual displacement calculating means 16: If it is determined in step S7 that it is within the allowable range, the seismic isolation layer 3 earthquake is determined from the respective accelerations at the time of the earthquake recorded by the earthquake acceleration recording means 13 (S4). A displacement history and a residual displacement δ ′ are calculated (S8). The residual displacement δ ′ is a horizontal displacement remaining in the seismic isolation layer 3 after the earthquake is stopped. The earthquake displacement history / residual displacement calculation means 16 performs the process of step S8.
Specifically, the earthquake displacement history / residual displacement calculating means 16 calculates the seismic isolation layer displacement by integrating the difference between the acceleration of the ground and the building twice in time. The displacement value after the earthquake is the residual displacement δ ′. However, the calculation of the residual displacement δ ′ is based on the above, but various methods may be used to improve accuracy.

  Seismic isolation layer energy absorption amount calculation means 17: After step S8, the residual energy absorption amount that can be absorbed by the seismic isolation layer 3 is calculated from the residual displacement δ ′ calculated by the displacement history / residual displacement calculation means 16 during the earthquake. (S9). The seismic isolation layer energy absorption amount calculation means 17 performs the process of step S9.

  Aftershock response capability determining means 18: After step S9, it is determined whether the calculated residual energy absorption amount of the seismic isolation layer 3 is sufficient for the assumed aftershock (S10). The assumed aftershock is the maximum aftershock of the ratio determined according to the main shock recorded by the earthquake acceleration recording means 13 (S4) or the like, and is converted into the amount of energy borne by the seismic isolation layer 3. 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 18 performs the process of step S10.

  Seismic isolation layer response displacement calculation means 21: Residual displacement δ of base isolation layer 3, base isolation force restoring force characteristic K, and amplification of surface ground 4b from engineering base 4a in the design of building 3 or in normal times Based on the rate 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. This calculation is not shown in the flow diagram of FIG. 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 21 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.

The outline of the equivalent linearization method is a method for obtaining the response displacement simply by using the first natural period of the building. The equivalent linearization method can be used to model the building in an equivalent one-mass system and to design extremely rare earthquakes. This is a method for calculating a response displacement by calculating a maximum response acceleration (estimated value) using a response spectrum.
The equivalent linearization method can be explained with mathematical formulas very simply:
δ = A ・ G ・ √ (M / K)
It is.
Where A: coefficient,
M: building mass, G: ground gain,
K: Seismic isolation resilience characteristics,
It is.
The time history response analysis can be summarized as follows: the building is modeled by mass, spring, and damping, and the ground surface is given a ground acceleration that changes with time, and the response acceleration, speed, and displacement of each floor of the building are expressed. It is a calculation method.

Seismic isolation force restoring force characteristic setting means 19: Earthquake acceleration recorded by the earthquake acceleration recording means 13 and earthquake displacement history of the seismic isolation layer 3 calculated by the earthquake displacement history / residual displacement calculation means 16 From this, the base isolation force restoring force characteristic K ′ is calculated and reset in the base isolation layer response displacement calculating means 21 (S11). The seismic isolation force restoring force characteristic setting means 19 performs the process of step S3. Explaining an example of how to obtain the seismic isolation force restoring force characteristic K ′, FIG. 5 is obtained from 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 layer amplification factor calculation means 20: After step S11, the amplification factor G 'of the surface layer from the engineering base is calculated from the ground natural period Tg' calculated by each natural period calculation unit 14 after the earthquake ( S12). The post-earthquake surface ground gain calculation means 20 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.

  Response displacement safety determination means 22: 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 the seismic isolation building safety evaluation system 1 of this embodiment, the post-earthquake residual displacement δ ′, the seismic isolation force restoring force characteristic K ′, and the surface ground amplification factor G ′ are obtained, and based on these, after the earthquake The response displacement of the seismic isolation layer 3 is calculated. The response displacement thus obtained is compared with the design limit to determine whether or not it is safe.
In this way, in the base-isolated building 2, considering the property changes of the building 2 (including the base-isolated layer 3) and the ground 4, set the building and ground conditions and perform analysis based on this. Thus, the safety can be determined according to the actual situation. Therefore, appropriate safety evaluation can be performed.

The building natural period change determining means 15 determines whether the change of the building natural period T ′ after the earthquake with respect to the normal building natural period T is within the allowable range. Judged as dangerous. Therefore, when it is clearly seen as dangerous by looking at the change in the natural period of the building, it can be determined as dangerous without performing various calculations for the ground.
It should be noted that the building natural period T ′ becomes longer than usual when the building is damaged by an earthquake, for example, when the brace is stretched or when the column beam joint is damaged.

  The base isolation layer response displacement calculating means 21 is based on the residual displacement δ of the base isolation layer 3, the base isolation force restoring force characteristic K, and the amplification factor G of the surface layer ground 4b in the design of the building 2 or in normal times. , A means for calculating the response displacement of the seismic isolation layer 3, and using this seismic isolation layer response displacement calculation means 21, after the earthquake, the residual displacement δ ′, the seismic isolation force restoring force characteristic K ′, and the surface ground gain G Reset to ′ and recalculate. For this reason, safety determination based on response displacement can be performed without providing a dedicated seismic isolation layer response displacement calculation means for post-earthquake use. Since the same seismic isolation layer response displacement calculation means 21 performs calculation at normal time and after the earthquake at the time of design, uniform and reliable safety judgment can be performed.

  If it is determined by the building natural period change determining means 15 (S7) that it is within the allowable range, the residual energy absorption amount that can be absorbed by the seismic isolation layer 3 is calculated from the calculated residual displacement δ ', and the residual energy is calculated. It is determined whether or not the amount of absorption is sufficient for an assumed aftershock (S10), and it is determined whether or not it is safe. Therefore, safety against aftershocks can be determined.

DESCRIPTION OF SYMBOLS 1 ... Safety evaluation system 2 ... Building 3 ... Seismic isolation layer 4 ... Ground 4a ... Engineering base 4b ... Surface layer ground 5 ... Base 6 ... Building body 8a, 8b ... Accelerometer 10 ... Evaluation operation part 11 ... Each normal Natural period calculation means 12 ... Earthquake detection means 13 ... Earthquake acceleration recording means 14 ... Each natural period calculation means 15 after earthquake ... Building natural period change judgment means 16 ... Earthquake displacement history / residual displacement calculation means 17 ... Seismic isolation layer energy Absorption amount calculating means 18 ... aftershock response capability judging means 19 ... base isolation force restoring force characteristic setting means 20 ... post-earthquake surface layer amplification factor calculating means 21 ... base isolation layer response displacement calculating means 22 ... response displacement safety judging means

Claims (3)

A seismic isolation system safety evaluation system for evaluating safety after an earthquake in a building having a seismic isolation layer, the ground on which the building is located or a portion corresponding to the ground, and an acceleration provided for each of the buildings And an evaluation calculation unit,
The evaluation calculation unit includes:
A normal period natural period calculating means for measuring the normal vibration of the ground and the building by each accelerometer and calculating the normal period natural period Tg and the natural period T of the building;
An earthquake acceleration recording means for recording the acceleration measured by each of the accelerometers at the time of the earthquake due to the occurrence of the earthquake;
Each post-earthquake natural period calculating means for calculating the natural period Tg ′ and the natural period T ′ of the building after the earthquake by measuring the micro-vibration of the ground and the building with each accelerometer after the occurrence of the earthquake;
A building natural period change determining means for determining whether or not a change of the natural period T ′ of the building after the earthquake with respect to the normal natural period T of the building is within an allowable range; ,
An earthquake displacement history / residual displacement calculating means for calculating an earthquake displacement history and a residual displacement δ ′ of the seismic isolation layer from the respective accelerations during the earthquake recorded by the earthquake acceleration recording means;
Based on the earthquake acceleration recorded by the earthquake acceleration recording means and the earthquake displacement history of the base isolation layer calculated by the earthquake displacement history / residual displacement calculation means, the base isolation force restoring force characteristic K ′ is calculated. Seismic isolation restoring force characteristic setting means,
A post-earthquake ground surface amplification factor calculating means for calculating the amplification factor G ′ of the surface layer from the engineering base based on the natural ground period Tg ′ calculated by each natural period calculating unit after the earthquake;
Based on the residual displacement δ ′ after the earthquake calculated by the above means, the seismic isolation force restoring force characteristic K ′, and the surface ground amplification factor G ′, the response displacement of the base isolation layer after the earthquake by a predetermined calculation method Seismic isolation layer response displacement calculating means for calculating
It is determined whether or not the response displacement calculated by this means is within the design limit. If it is within the design limit, it is determined to be safe, and if it is within the design limit, response displacement safety determination means is determined to be dangerous.
A safety evaluation system for base-isolated buildings.   In Claim 1, the said seismic isolation layer response displacement calculation means is the design of the said building, or the normal displacement in the normal time, the residual displacement (delta) of the said seismic isolation layer, the seismic isolation force restoring force characteristic K of the said seismic isolation layer, A means for calculating the response displacement of the base isolation layer by a predetermined calculation method based on the amplification factor G of the surface layer from the engineering base, the residual displacement δ, the base isolation force restoring force characteristic K, and the surface layer A seismic isolation building safety evaluation system that recalculates the ground amplification factor G after resetting it to the residual displacement δ 'after the earthquake, seismic isolation force restoring force characteristics K', and surface ground amplification factor G '. 3. The seismic isolation system according to claim 1 or 2, wherein when the building natural period change determining means determines that it is within an allowable range, the residual displacement δ ′ calculated by the earthquake displacement history / residual displacement calculating means is used. Seismic isolation layer energy absorption amount calculating means for calculating the amount of residual energy absorption that can be absorbed by the layer,
Determining whether the residual energy absorption of the seismic isolation layer calculated by this means is sufficient for the assumed aftershock, and, if not sufficient, aftershock response capability determining means for determining as dangerous,
A safety evaluation system for base-isolated buildings.

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