Damage grade estimation system, acceleration estimation method and acceleration estimation program

Abstract

To provide technology that highly accurately and efficiently conducts evaluation on a state of a building.SOLUTION: In a damage grade estimation system 1, four acceleration meters are basically installed in a building, firstly records by the acceleration meters are synchronized when earthquake breaks out (S10); an absolute acceleration in a floor where the acceleration meters are not installed is estimated on the basis of a result of two kinds of cubic spline interpolations using the record of the acceleration meter, and information on a height of the building and a floor height thereof (S20); a maximum absolute acceleration and maximum inter-layer deformation angle in each floor of the building are calculated on the basis of an actual measurement value and estimation value of the absolute acceleration (S30); determination on a state of the building by comparison of these values with a predetermined threshold is made (S40); and a determination result is reported by screen display, voice output and the like (S50). According to the damage grade estimation system 1, the estimation of the absolute acceleration or the evaluation of the state of the building in the floor where the acceleration meters are not installed can be highly accurately and efficiently conducted from limited information, not performing advance analysis on the building.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to a system for estimating the degree of earthquake damage to a building based on records of the time period during which an earthquake occurred taken by a plurality of accelerometers installed in the building. [Background technology]

[0002] In recent years, as part of structural health monitoring, various systems have been developed that install multiple accelerometers in buildings and evaluate the soundness of buildings from the results of analyzing their records. These systems have in common that they determine the damage status of buildings based on the records of multiple accelerometers when an earthquake occurs and display the results on a screen, but they differ in how they respond to the time discrepancy between the multiple accelerometers, how they handle floors where accelerometers are not installed, and how they determine the damage status.

[0003] Regarding the handling of floors on which accelerometers are not installed, for example, Patent Document 1 discloses that the inter-story deformation angle on each floor of a building is calculated from the results of a static incremental analysis, the floors on which accelerometers are installed are determined so that the variation in the magnitude of the inter-story deformation angle within a section is reduced, and when performing an evaluation, the section deformation angle is calculated based on the detection results of accelerometers installed on floors (e.g., the first and fourth floors) that sandwich a certain section (e.g., the section from the first to third floors), and the value is applied as the inter-story deformation angle of each floor (e.g., the first, second, and third floors) in that section. Another possible method is to prepare an analysis model dedicated to the target building in advance, and use the analysis model to calculate values ​​on floors on which accelerometers are not installed when performing an evaluation. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent Publication No. 2022-65321 Summary of the Invention [Problem to be solved by the invention]

[0005] In the former prior art, a static incremental analysis must be performed before installing accelerometers, and the same value is applied as the inter-story drift angle for multiple floors in the same section, which may affect the accuracy of the evaluation. In the latter method, a dedicated analysis model is used, so it is assumed that values ​​for floors where accelerometers are not installed can be calculated with a certain degree of accuracy, but it requires a great deal of effort because an analysis model must be prepared for each building. Therefore, a method that can achieve both accuracy and efficiency in the evaluation of the condition of a building is required.

[0006] Therefore, an object of the present invention is to provide a technique for evaluating the condition of a building accurately and efficiently. [Means for solving the problem]

[0007] In order to solve the above problems, the present invention employs the following damage estimation system. The present invention also employs, as an acceleration estimation method and an acceleration estimation program, a configuration equivalent to the acceleration estimation means in the damage estimation system. Note that the following words in parentheses are merely examples, and the present invention is not limited thereto.

[0008] In other words, the damage extent estimation system of the present invention comprises a recording synchronization means for synchronizing absolute acceleration records from a plurality of accelerometers, one of which is installed at the top end, one of which is installed at the bottom end, and one of which is installed at at least two other locations in accordance with a predetermined rule on the above-ground portion of the building; an acceleration estimation means for performing cubic spline interpolation on the absolute acceleration at each time during the time zone of the earthquake occurrence based on the absolute acceleration records from the plurality of accelerometers after synchronization and the height of the building, and estimating the absolute acceleration during the time zone of the earthquake occurrence for each floor on which an accelerometer is not installed from the result; a condition determination means for determining the maximum absolute acceleration and maximum inter-storey deformation angle during the time zone of the earthquake occurrence for each ground floor of the building based on the absolute acceleration recorded on each floor on which an accelerometer is installed and the absolute acceleration estimated for each floor on which an accelerometer is not installed, and for making a determination regarding the condition of each upper floor by comparing the maximum absolute acceleration and maximum inter-storey deformation angle with predetermined threshold values ​​for each of the maximum absolute acceleration and maximum inter-storey deformation angle; and a result notification means for notifying the condition of each upper floor at least by displaying on a screen.

[0009] According to this aspect of the damage estimation system, absolute accelerations on floors where accelerometers are not installed are estimated by cubic spline interpolation using records from multiple accelerometers installed in the building and information on the building's height, so there is no need to perform a prior analysis of the building and absolute accelerations can be estimated efficiently. Furthermore, the maximum absolute accelerations and maximum inter-story drift angles during the time of earthquake occurrence on each ground floor of the building are calculated using the estimated values ​​obtained in this way and the actual values ​​measured by the accelerometers, and these values ​​are used to determine the condition of each upper floor, so that the determination can be made accurately and efficiently.

[0010] Preferably, in the damage degree estimation system of the above aspect, when the rigidity of the building is 0.6 or more, the remaining accelerometers are installed on floors that divide the height between the upper end and the lower end in approximately equal positions, while when the rigidity of the building is less than 0.6, the accelerometers are first installed at the upper end and the lower end and above and below the floors where the rigidity is less than 0.6, and the remaining accelerometers are installed on floors that divide the height between the upper end or the lower end and the nearest floor where the accelerometer is installed in approximately equal positions. Also, when the eccentricity of the building exceeds 0.15, the accelerometers are installed near the exterior wall on the side farther away from the rigidity center.

[0011] Generally, in buildings with a rigidity coefficient of 0.6 or more, there is not much difference in the rigidity coefficient of each floor, and it is unlikely that a specific floor will collapse even if an earthquake occurs. In contrast, in buildings with a rigidity coefficient of less than 0.6, floors with low rigidity coefficients tend to be particularly susceptible to collapse.

[0012] According to this aspect of the damage estimation system, when the rigidity of the building is 0.6 or more, the multiple accelerometers are installed at positions with approximately equal intervals (heights) between them, so that when estimating the absolute acceleration on floors where no accelerometers are installed based on the results of cubic spline interpolation, it is possible to prevent bias in the estimated value. Also, when the rigidity of the building is less than 0.6, the accelerometers are installed on the upper and lower sides of floors where the rigidity is less than 0.6, and when the eccentricity exceeds 0.15, the accelerometers are installed near the outer wall on the side farther away from the rigidity center, so that it is possible to focus on observing floors that are easily damaged and to make an accurate evaluation.

[0013] More preferably, in the damage degree estimation system of any of the above-mentioned aspects, the acceleration estimation means sets, as boundary conditions for the cubic spline interpolation, a first condition under which the first derivative is zero at the upper end point corresponding to the recorded value at the upper end and at the lower end point corresponding to the recorded value at the lower end, and a second condition under which the third derivative at the upper end point and the lower end point is the same as that at adjacent points, and estimates the absolute acceleration during the time zone of the earthquake on each floor where an accelerometer is not installed from the result of adding together the results of the two types of cubic spline interpolation calculated under the first condition and the second condition in a predetermined ratio.

[0014] According to this embodiment of the damage estimation system, two boundary conditions are set and two types of cubic spline interpolation are performed, and the results of each interpolation are added together at a predetermined ratio determined in advance based on verification, thereby enabling an accurate estimation of the absolute acceleration during the time of the earthquake on each floor where an accelerometer is not installed.

[0015] More preferably, in the damage extent estimation system of any of the above-mentioned aspects, the recording synchronization means calculates a correlation function for the absolute displacement at the position where each accelerometer is installed, calculated by second-order integration of the absolute acceleration recorded by two of the multiple accelerometers during the time when the earthquake occurred, and calculates a correlation function with a step number corresponding to the difference in time at which the absolute acceleration was recorded by the two accelerometers as a variable, and identifies the step number at which the correlation function reaches its peak value closest to step number 0 and multiplies the step number by the recording time interval, thereby identifying the time difference between the two accelerometers.

[0016] The accelerometer records the acceleration it observes along with the time indicated by its built-in clock (hereinafter referred to as the "internal time"). However, as the internal times of multiple accelerometers become misaligned over time, some method is required to synchronize the internal times or recorded data.

[0017] In this aspect of the damage estimation system, absolute displacement is obtained from the absolute acceleration recorded by the two accelerometers to calculate the correlation function of absolute displacement, but in the correlation function of absolute displacement, there is only one point where correlation is high near the step number 0. Therefore, according to this aspect of the damage estimation system, the step number corresponding to the internal time shift can be uniquely identified from the correlation function of absolute displacement, and based on this, the amount of internal time shift can be accurately identified and the absolute acceleration records by the two accelerometers can be appropriately synchronized, and by successively changing the combination of the two accelerometers, it becomes possible to appropriately synchronize the absolute acceleration records by all of the accelerometers. Effect of the Invention

[0018] As described above, according to the present invention, evaluation of the condition of a building can be performed accurately and efficiently. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a diagram showing an operating environment of a damage extent estimation system 1. [Diagram 2] FIG. 2 is a diagram illustrating an arrangement of a plurality of accelerometers. [Diagram 3] FIG. 1 is a block diagram of a damage extent estimation system 1. [Figure 4] 4 is a flowchart showing the flow of processing executed in the damage degree estimation system 1 when an earthquake occurs. [Diagram 5] 10 is a flowchart illustrating an example of a procedure for acceleration record synchronization processing. [Figure 6] FIG. 13 shows the correlation function of absolute displacement and the correlation function of absolute acceleration calculated based on recordings by two accelerometers. [Figure 7] FIG. 1 shows an example of synchronizing recordings from two accelerometers. [Figure 8] 10 is a flowchart illustrating an example of a procedure for acceleration estimation processing. [Figure 9] FIG. 1 is a diagram illustrating cubic spline interpolation. [Figure 10]FIG. 13 is a diagram showing an example of a time history waveform of estimated acceleration obtained by performing cubic spline interpolation on records for all times during the time period in which an earthquake occurred. [Figure 11] FIG. 13 is a diagram illustrating a determination regarding the state of a building. [Figure 12] 10 is a flowchart illustrating an example of a procedure for a state determination process. [Figure 13] FIG. 11 is a diagram showing an example of a manner in which a determination result is notified. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the following embodiment is a preferred example of a damage degree estimation system, and the embodiment of the present invention is not limited to this example.

[0021] [Operating environment for the damage estimation system] FIG. 1 is a diagram showing an operating environment of a damage extent estimation system 1 according to an embodiment. The damage extent estimation system 1 is a system in which multiple accelerometers are installed in a building, and when an earthquake occurs, the damage extent of each floor of the building is estimated based on the records of these accelerometers, and the results are notified in various ways.

[0022] In the illustrated example, accelerometers 10A, 10B, 10C, and 10D are installed at four locations on the first, third, sixth floor, and rooftop of a seven-story building BL. In this manner, in the damage degree estimation system 1, basically, four accelerometers 10 are installed on the ground portion of the building BL in accordance with a predetermined rule described later.

[0023] The damage degree estimation system 1 operates in an environment where a plurality of accelerometers 10 installed in a building BL are connected to a computer 30 installed on-site (for example, inside the building BL) that receives data from each accelerometer via a receiver 20 and executes processing to estimate the damage degree of the building BL. The accelerometers 10 and the receiver 20 are capable of wireless communication, and the on-site computer 30 receives data from each of the accelerometers 10 via the receiver 20. The computer 30 is also connected to a network 40, and is capable of communication with a management server (not shown) and the like.

[0024] The on-site computer 30 is installed with a program required for the processing of the damage degree estimation system 1. The on-site computer 30 may be a general-purpose computer equipped with a CPU, RAM, HDD, various I / Fs, a display, a speaker, etc., or may be a device designed specifically for the damage degree estimation system 1. In the illustrated example, the receiver 20 is connected to the on-site computer 30, but instead, the functions of the receiver 20 may be built into the on-site computer 30.

[0025] [Arrangement of multiple accelerometers] FIG. 2 is a diagram illustrating an arrangement of a plurality of accelerometers 10. As shown in FIG. To improve the accuracy of evaluation of the building condition, it is desirable to install accelerometers on every floor. However, due to issues of introduction and operation costs, structural constraints such as lack of installation space, and psychological factors such as feeling that accelerometers are in the way, it is difficult to install accelerometers on every floor in reality.

[0026] In this embodiment, the number of accelerometers to be installed is basically four, and two patterns are broadly defined for the placement of the accelerometers. When introducing the system, one of the patterns is applied depending on the rigidity of the building to which the system is to be introduced. In either pattern, the accelerometers are always installed at the upper end (e.g., rooftop) and lower end (e.g., first floor) of the above-ground portion of the building.

[0027] 2(A): When the rigidity of the building is 0.6 or more, one accelerometer is installed on the first floor and one on the roof, and the other accelerometers are installed on floors that divide the distance (height) between these two accelerometers into approximately equal parts. For example, as shown in the example, in a seven-story building BL with a rigidity of 0.6 or more, one accelerometer 10 is installed on each of the first floor, third floor, sixth floor, and roof.

[0028] In Figure 2 (B): If the rigidity modulus of building BL is less than 0.6, one accelerometer is installed on the first floor and on the roof, and an accelerometer is also installed on either side of the floor with a rigidity modulus of less than 0.6. In areas where the spacing between the multiple accelerometers is large, other accelerometers are installed on floors that divide the spacing (height) approximately equally.

[0029] For example, as in the example shown in the figure, in a seven-story building BL with a rigidity modulus of less than 0.6, if the rigidity modulus of the seventh floor is 0.4 and the rigidity moduli of the other floors are 0.6 or greater, accelerometers 10 are first installed on the first floor and roof, and then installed at positions on either side of the seventh floor, i.e., above and below the seventh floor. However, since there is an accelerometer 10 on the roof above, an accelerometer 10 is installed below on the seventh floor, and the remaining accelerometer 10 is installed on the fourth floor, which is at a height that divides the space between the first and seventh floors approximately equally.

[0030] Although the seven-story building BL is used as an example, the number of floors of the building in which the damage estimation system 1 is installed is not limited to this. If an accelerometer cannot be installed on the rooftop of the building for some reason, it may be installed on the ceiling of the top floor instead of the rooftop. The same applies to the accelerometers on each floor. If it is difficult to install an accelerometer on the floor of the target floor, it may be installed on the ceiling of the floor below instead of the floor of the target floor.

[0031] Also, although not shown in the figure, when the eccentricity of the building BL exceeds 0.15, an accelerometer is installed near the exterior wall on the side opposite the center of rigidity, in other words, on the side farther away from the center of rigidity (the side farther from the center of rigidity).

[0032] Furthermore, in the damage extent estimation system 1, basically, four accelerometers are sufficient, but depending on the number and locations of floors with a rigidity rate of less than 0.6, more than four accelerometers 10 may be installed. Regardless of the rigidity rate of the building, more than four accelerometers 10 may be installed if costs and other circumstances permit.

[0033] For ease of explanation, the following description will be given of an example in which four accelerometers are arranged in the manner shown in FIG. 1, i.e., accelerometers 10A, 10B, 10C, and 10D are installed on the first, third, sixth floor, and rooftop, respectively, of a seven-story building BL.

[0034] [Configuration of the damage estimation system] 3 is a block diagram of the damage degree estimation system 1. The configuration of the damage degree estimation system 1 will be described below along with the flow of information in the damage degree estimation system 1.

[0035] As described above, multiple (basically four) accelerometers 10A, 10B, 10C, and 10D are installed on the ground floor of building BL, and each accelerometer is set to start recording when a certain level of acceleration or more is applied to it. When an earthquake occurs, each accelerometer 10A, 10B, 10C, and 10D starts recording absolute acceleration and transmits the data to the on-site computer 30 via the receiver 20. The records from each accelerometer can be stored in its own built-in memory or a recording medium such as an SD card. If the computer 30 cannot receive data due to some kind of failure, each accelerometer can resend the data to the computer 30 after the failure is restored.

[0036] The on-site computer 30 has, for example, a memory unit 31, a synchronization unit 32, an acceleration estimation unit 33, a state determination unit 34, a notification processing unit 35, a display 36, a speaker 37, a data transmission unit 38, etc. Among these, the synchronization unit 32, the acceleration estimation unit 33, the state determination unit 34, the notification processing unit 35, and the data transmission unit 38 correspond to programs for the damage extent estimation system 1, and a processor 39 of the on-site computer 30 is the main operating unit for these units. The memory unit 31 is a storage area such as an HDD or RAM, and stores data received from each accelerometer, values ​​obtained in the process of processing, a history of past determination results, etc.

[0037] The synchronizing unit 32 synchronizes the absolute acceleration records by the multiple accelerometers based on the data stored in the memory unit 31. The acceleration estimating unit 33 estimates the absolute acceleration during the time of earthquake occurrence on each floor where no accelerometer is installed, using the records synchronized by the synchronizing unit 32. The state determining unit 34 determines the state of each upper floor based on the actual measured value of absolute acceleration on each floor where an accelerometer is installed and the estimated value of absolute acceleration for each floor where no accelerometer is installed.

[0038] The notification processing unit 35 generates a screen showing the determination result by the status determination unit 34 in characters and figures, displays it on the display 36, and notifies the user by voice from the speaker 37. The notification processing unit 35 also creates a message notifying the user of the determination result and transmits it to a preset destination list. The notification processing unit 35 can also display a history of past determination results in response to a request from the user of the local computer 30. The data transmission unit 38 transmits the determination result by the status determination unit 34 to the management server 50 together with basic information such as the identification information of the building BL and the time of the earthquake occurrence.

[0039] The management server 50 has, for example, a database 51, a data receiving unit 52, and a notification screen generating unit 53. The database 51 is a database for managing the history of result data processed in various buildings. The data receiving unit 52 receives data transmitted from the local computer 30 and stores the data in the database 51. The notification screen generating unit 53 is a web application, and generates a screen showing the determination result related to the building BL in characters and figures in response to a request from the information terminal 60. The screen generated by the notification screen generating unit 53 is generally similar to the screen generated by the notification processing unit 35 of the local computer 30.

[0040] The information terminal 60 is a smartphone, tablet terminal, mobile PC, or the like used by a user of the damage degree estimation system 1, and is equipped with a general mailer 61 and browser 62. The user can receive a message of the determination result sent by the notification processing unit 35 via the mailer 61. Even if the user does not receive a message, the user can access a predetermined URL via the browser 62 to refer to the latest determination result and the history of past determination results regarding the building BL.

[0041] In the illustrated example, the computer 30 is connected to the network 40, and the configuration assumes that the management server 50 and information terminal 60 exist on the network 40, but even if the computer 30 is not connected to the network 40 or the network 40 is unusable due to a failure or the like, the damage extent estimation system 1 can operate as a standalone and provide a full range of functions. In this case, the target of notification of the determination result is limited to the on-site computer 30 only.

[0042] Also, in the above example, the management server 50 serves as both a database server and an application server, and all functions are implemented on the same server, but each function may be implemented on a different server.

[0043] [Processing flow when an earthquake occurs] 4 is a flowchart showing the flow of processes executed when an earthquake occurs in the damage degree estimation system 1. Each process will be described below in accordance with the flow.

[0044] Step S10: Acceleration record synchronization processing is executed. In this processing, the synchronization unit 32 synchronizes the recording of absolute acceleration by the multiple accelerometers. Note that the specific contents of the acceleration record synchronization processing will be described further below with reference to another drawing.

[0045] Step S20: Acceleration estimation processing is executed for floors where no accelerometers are installed. In this processing, the acceleration estimation unit 33 uses the records synchronized in step S10 to perform cubic spline interpolation between discrete points corresponding to the actual measured values ​​for each recording time using the actual measured values ​​(recorded values) by the multiple accelerometers and the building height information, and estimates the absolute acceleration at that time for each floor where no accelerometer is installed based on the results. The specific contents of the acceleration estimation processing will be described in detail later with reference to another drawing.

[0046] Step S30: Based on the absolute acceleration recorded by the multiple accelerometers synchronized in step S10 and the absolute acceleration estimated in step S20 on each floor where an accelerometer is not installed, the maximum absolute acceleration and maximum story deformation angle during the time of earthquake occurrence on each upper floor of the building are calculated.

[0047] Step S40: A state determination process is executed. In this process, the state determination unit 34 compares the maximum absolute acceleration and maximum inter-story drift angle calculated in step S30 with preset thresholds for each of the maximum absolute acceleration and maximum inter-story drift angles to determine the state of each upper floor of the building. The specific contents of the state determination process will be described later with reference to another drawing.

[0048] Step S50: A determination result notification process is executed. In this process, the notification processor 35 notifies the result of the determination obtained in step S40 by using various means such as a screen display or audio output, and also transmits a message notifying the determination result to a preset destination list, transmits result data to a management server, etc.

[0049] [Acceleration record synchronization processing] FIG. 5 is a flowchart showing an example of the procedure of the acceleration record synchronization process (step S10 in FIG. 4).

[0050] In multiple accelerometers, deviations occur in the internal times over time. In the case of wired accelerometers, it is easy to synchronize the internal times of each accelerometer from a computer connected to each accelerometer by wire, but in the case of wireless accelerometers, it is preferable to achieve synchronization by a different method in consideration of circumstances specific to wireless communication. Therefore, in this embodiment, instead of synchronizing the internal times of the multiple accelerometers, records made by the multiple accelerometers are synchronized according to the following example procedure.

[0051] Step S11: The synchronization unit 32 first selects two accelerometers installed in close proximity to each other from among the multiple accelerometers installed in the building BL. When step S12 is executed for the first time, for example, the accelerometer 10A installed on the first floor and the accelerometer 10B installed on the third floor, which is the closest to the accelerometer 10A, are selected. Since seismic waves arrive at adjacent accelerometers almost simultaneously, by selecting such two accelerometers, it becomes possible to efficiently perform subsequent processing (calculation of correlation functions and therefore synchronization of records) without worrying about the time difference in the arrival timing of seismic waves.

[0052] Step S12: The synchronization unit 32 performs a second-order integration of the absolute accelerations recorded at each time during the earthquake occurrence time zone by the two accelerometers selected in step S11, and calculates the absolute displacement of each accelerometer (the absolute displacement at the position where the accelerometer is located).

[0053] Step S13: The synchronization unit 32 then calculates a correlation function for the absolute displacements of the two accelerometers calculated in step S12, with the number of steps corresponding to the difference in time at which the absolute accelerations are recorded by the two accelerometers as a variable. In other words, this correlation function indicates how the correlation between the absolute displacement of one accelerometer and the absolute displacement of the other accelerometer changes when the recording time of one accelerometer is shifted forward or backward. By calculating the correlation function, it is possible to specify the number of steps at which the correlation between the absolute displacements of the two accelerometers becomes high.

[0054] Steps S14 and S15: The synchronization unit 32 identifies the number of steps at which the correlation function calculated in step S13 reaches a peak value near step 0 as the "deviation step" corresponding to the deviation in the internal time of the two accelerometers (step S14), and multiplies the deviation step by the recording interval of the absolute acceleration to identify the deviation width of the internal time of one accelerometer relative to the other accelerometer (step S15).

[0055] For example, in each accelerometer installed in building BL, observation values ​​are recorded every 5 ms (=0.005 seconds). In this case, if the deviation step is "15", the internal time deviation is specified as "0.075 seconds (=15 x 0.005)", and if the deviation step is "-40", the internal time deviation is specified as "-0.2 seconds (=-40 x 0.005)".

[0056] The reason for specifying the deviation step near step 0 is that it is operationally known that the internal times of the multiple accelerometers do not deviate significantly, and even if there is a deviation, it will be small (a deviation width roughly corresponding to the number of steps near 0). Therefore, it is sufficient to specify the number of steps at which the correlation function reaches its peak value near 0.

[0057] Step S16: Next, the synchronization unit 32 corrects the time recorded by one of the accelerometers in accordance with the time offset determined in step S15 (sliding the entire waveform forward (to the left, toward the past) or backward (to the right, toward the future) relative to the time axis of the recording), thereby synchronizing the absolute acceleration recorded by one accelerometer with the absolute acceleration recorded by the other accelerometer.

[0058] For example, if the internal time deviation in one accelerometer is identified as "0.075 seconds" in step S15, the recording time of the absolute acceleration by that accelerometer is corrected to be advanced by 0.075 seconds (the entire waveform is slid backward by 0.075 seconds), and if the internal time deviation in one accelerometer is identified as "-0.2 seconds", the recording time of the absolute acceleration by that accelerometer is corrected to be reversed by 0.2 seconds (the entire waveform is slid forward by 0.2 seconds).

[0059] Step S17: The synchronization unit 32 checks whether or not the records from all accelerometers installed in the building BL have been synchronized, and if the records from all accelerometers have not been synchronized, that is, if there are any accelerometers whose records are not synchronized (not targeted for execution of steps S11 to S15) (step S17: No), the synchronization unit 32 returns to step S11, selects an unsynchronized accelerometer as one of two adjacent accelerometers and a synchronized accelerometer as the other, and then executes the procedure of steps S12 to S16. On the other hand, if the records from all accelerometers have been synchronized (step S17: Yes), the synchronization unit 32 proceeds to step S18.

[0060] Step S18: The synchronization unit 32 detects whether the height of the building BL is a predetermined threshold H Th Check whether it is greater than or equal to a certain threshold H Th is a predetermined criterion for determining whether a building is a medium- to high-rise building, and may be, for example, 20 m or 30 m. ThIf the height of the building BL is equal to or greater than the predetermined threshold H Th If it is less than this, that is, if the building BL is not a medium- to high-rise building (step S18: No), the synchronization unit 32 ends the acceleration record synchronization process.

[0061] Step S19: The synchronizer 32 executes a transmission time adjustment process. In mid- to high-rise buildings, it takes time for an earthquake to reach the upper floors, so the time when the absolute displacement reaches its maximum varies depending on the floor on which the accelerometer is installed (more precisely, the height at which the accelerometer is installed). Therefore, simply synchronizing the records using the above-mentioned procedure does not take into account the time it takes for the earthquake to reach the upper floors, and this may affect the accuracy of the state determination process that will be executed later.

[0062] Therefore, in this embodiment, when the building BL is a medium- to high-rise building, an adjustment is made for the earthquake propagation time. First, the synchronization unit 32 calculates the earthquake propagation time for all the accelerometers by the following formula.

[0063]

number

[0064] In the above formula, "t" is the earthquake propagation time (unit: s), "H" is the height at which the accelerometer is installed (unit: m), and "V h " is the predetermined earthquake propagation speed in the vertical direction (unit: m / s). Then, the synchronization unit 32 performs a correction to delay the time recorded by each accelerometer by t seconds, that is, to add t seconds to the recorded time (slide the entire waveform backward (to the right, toward the future) by t seconds). Note that if the calculated time t is smaller than the recording interval of the accelerometer, the synchronization unit 32 does not perform the correction.

[0065] The above procedure is merely an example and can be modified as appropriate. For example, in the above procedure, the earthquake transmission times for all accelerometers are adjusted collectively in the final transmission time adjustment process, but instead, the transmission time adjustment process for one accelerometer may be performed in the process of synchronizing the records of each accelerometer, specifically, immediately after the execution of step S16.

[0066] Figure 6 shows a specific example of the correlation function of absolute displacement calculated based on records from two accelerometers during the time of an earthquake, and the correlation function of absolute acceleration calculated for comparison. Of these, (A) is when an earthquake under a first condition was observed by two accelerometers placed on a test structure simulating a building, and (B) is when an earthquake under a second condition was observed by two accelerometers placed on the same test structure. In each graph, the solid line indicates the correlation function of absolute displacement, and the dashed line indicates the correlation function of absolute acceleration.

[0067] As is clear from these graphs, in the correlation function of absolute acceleration, there are multiple points where the correlation is high near the step number of 0 (points circled in each graph), so it is not clear which peak step number should be identified as the deviation step. Also, depending on the range of records targeted when calculating the correlation function, it may be difficult to identify the deviation step.

[0068] In contrast, in the correlation function of absolute displacement, there is only one point where the correlation is high near step number 0, and the same result is obtained even if records at all times during the time period when the earthquake occurred are considered when calculating the correlation function. Therefore, by using the correlation function of absolute displacement, it is possible to uniquely identify the shift step from the peak immediately adjacent to step number 0, and based on this, it is possible to accurately calculate the internal time shift width.

[0069] Specifically, in the case of (A), since the correlation function of absolute displacement reaches its peak value at step number "-43", the deviation step is identified as "-43", and the deviation width of the internal time of one accelerometer relative to the other accelerometer is identified as "-0.215 seconds (=-43 x 0.005)".

[0070] Fig. 7 shows an example of synchronizing absolute acceleration records by two accelerometers (first floor accelerometer and third floor accelerometer) that are the basis for calculating the correlation function shown in Fig. 6(A), as a specific example of synchronizing absolute acceleration records by two accelerometers. To facilitate understanding of the invention, Fig. 7 shows the first five seconds of records made by each accelerometer during the time when the earthquake occurred.

[0071] In Figure 7 (A), the upper graph shows the absolute acceleration recorded by the 1st floor accelerometer, and the lower graph shows the absolute acceleration recorded by the 3rd floor accelerometer. These records are before synchronization, that is, they are in the state collected from each accelerometer. In the record by the 1st floor accelerometer, the absolute acceleration starts to fluctuate from the latter half of the 1s range, while in the record by the 3rd floor accelerometer, the absolute acceleration starts to fluctuate just before the 2s range, so it is clear that there is a time difference between the records by the two accelerometers.

[0072] For these two accelerometers, the correlation function of absolute displacement (Figure 6 (A)) specifies that the offset step is "-43" and the offset width of the internal time of the 3rd floor accelerometer (one of the accelerometers) relative to the 1st floor accelerometer (the other accelerometer) is "-0.215 seconds." Therefore, a correction is made to move the time recorded by the 3rd floor accelerometer back by 0.215 seconds (the entire waveform is slid forward by 0.215 seconds relative to the time axis of the recording).

[0073] Figure 7 (B) shows the results of correcting the time of the record from the third floor accelerometer by moving it back by 0.215 seconds, overlaid on the record from the first floor accelerometer. Before correction, the timing at which fluctuations in absolute acceleration began to occur in the record from the third floor accelerometer was clearly different from the record from the first floor accelerometer, but after correction, it roughly matches the record from the first floor accelerometer. This shows that by performing the correction described above, it is possible to properly synchronize the absolute acceleration records from the two accelerometers.

[0074] In this way, by following the procedure shown in steps S12 to S16 of the acceleration recording synchronization process (Figure 5), the correlation function of the absolute displacements of the two accelerometers is calculated, and this correlation function is used to identify the difference in the internal times of the two accelerometers.The time of recording by one of the accelerometers is corrected according to the difference, so that the recordings by the two accelerometers can be properly synchronized.By switching between the two target accelerometers and repeatedly executing steps S12 to S16, and in the case of a mid- to high-rise building, further executing step S19 (transmission time adjustment process), it is possible to ultimately properly synchronize the absolute acceleration recordings by all of the accelerometers installed in building BL.

[0075] [Acceleration Estimation Processing] 8 is a flowchart showing an example of the procedure of the acceleration estimation process (step S20 in FIG. 4). The example of the procedure will be described below.

[0076] Steps S21 and S22: First, the acceleration estimation unit 33 sets a time t to be subjected to subsequent processing among the times recorded by the accelerometers during the time zone in which the earthquake occurred (step S21), and obtains the recorded value of the absolute acceleration at time t by each accelerometer (step S22).

[0077] Steps S23 and S24: Next, the acceleration estimation unit 33 performs two types of cubic spline interpolation to interpolate between the discrete points corresponding to each recorded value at time t, taking into account the building height information. Specifically, as boundary conditions for the cubic spline interpolation, a first condition is set in which the first derivative is 0 at the upper end point corresponding to the recorded value by the accelerometer 10D installed on the rooftop and at the lower end point corresponding to the recorded value by the accelerometer 10A installed on the first floor, and a second condition is set in which the third derivative at the upper end point and the lower end point is the same as that at adjacent points (the third derivative is continuous at adjacent points of the upper end point and the lower end point), and the acceleration estimation unit 33 performs interpolation between the discrete points corresponding to each recorded value at time t using the first condition (step S23), and performs interpolation between the discrete points corresponding to each recorded value at time t using the second condition (step S24).

[0078] Step S25: Next, the acceleration estimation unit 33 adds the result of the cubic spline interpolation under the first condition and the result of the cubic spline interpolation under the second condition at a predetermined ratio (for example, 50% each). The ratio is not limited to 50% each, and for example, the result under the second condition can be adjusted to 50-60% and the ratio of the result under the first condition can be adjusted so that the sum of the two is 100% (for example, the result under the second condition is 55% and the result under the first condition is 45%). It has been confirmed by the inventors' verification that good estimation is possible by adding the results of two types of cubic spline interpolation at such a ratio.

[0079] Step S26: The acceleration estimation unit 33 estimates the absolute acceleration at time t on each floor on which an accelerometer is not installed from the curve obtained in step S25, and stores the estimated value in the storage unit 31.

[0080] Step S27: The acceleration estimation unit 33 checks whether all the times recorded by the accelerometer during the earthquake occurrence time period have been processed, and if all the times have not been processed, i.e., if there are times for which the absolute acceleration has not been estimated (step S27: No), the process returns to step S21 and repeats the subsequent steps. On the other hand, if all the times have been processed (step S27: Yes), the acceleration estimation unit 33 ends the acceleration estimation process.

[0081] Fig. 9 shows the result of adding together 50% of the results of two types of cubic spline interpolation performed based on the recorded values ​​at a certain time t during the time zone when the earthquake occurred, in order to explain the cubic spline interpolation performed during the acceleration estimation process (Fig. 8). Note that the vertical axis of the graph indicates height, and although processing is also based on height during the cubic spline interpolation, as it is necessary to ultimately determine the state of each floor and show the results, a scale indicating the height of each floor is added to the vertical axis as an auxiliary measure.

[0082] In the acceleration estimation process, first, actual measurement values ​​at time t are obtained by accelerometer 10A on the first floor, accelerometer 10B on the third floor, accelerometer 10C on the sixth floor, and accelerometer 10D on the rooftop. The points corresponding to these actual measurement values ​​(black circles in the figure) are discrete, but by performing two types of cubic spline interpolation and adding the results at a predetermined ratio, the intervals between these discrete points are interpolated to obtain a curve as shown in the graph. The absolute acceleration of the points (white circles in the figure) on this curve that correspond to the height of each floor where no accelerometer is installed is estimated as the absolute acceleration of that floor at time t.

[0083] The illustrated example is the result of cubic spline interpolation performed for one time t in the earthquake occurrence time zone, but similar processing is performed for all times in the earthquake occurrence time zone.

[0084] FIG. 10 is a diagram showing an example of a time history waveform of estimated acceleration obtained as a result of performing cubic spline interpolation on records for all times during the time period during which an earthquake occurred.

[0085] (A) in Fig. 10 shows the time history waveform of absolute acceleration observed by accelerometer 10B installed on the third floor, (B) in Fig. 10 shows the time history waveform of absolute acceleration estimated for the fourth floor where no accelerometer is installed, (C) in Fig. 10 shows the time history waveform of absolute acceleration estimated for the fifth floor where no accelerometer is installed, and (D) in Fig. 10 shows the time history waveform of absolute acceleration observed by accelerometer 10C installed on the sixth floor. Although not shown in the figure, for other floors (second floor, seventh floor) where no accelerometer is installed, time history of estimated values ​​of absolute acceleration can be obtained in the same way as for the fourth and fifth floors shown in the figure.

[0086] In this manner, in this embodiment, the acceleration estimation process (FIG. 8; step S20 in FIG. 4) provides a time history of estimated absolute acceleration values ​​during the time period when an earthquake occurred for each floor on which an accelerometer is not installed, and the subsequent processes (step S30 and thereafter in FIG. 4) can be executed using actual measured values ​​for floors on which an accelerometer is installed, while using estimated values ​​for floors on which an accelerometer is not installed.

[0087] Specifically, for each ground floor of building BL, first, the maximum absolute acceleration during the time of earthquake occurrence is calculated from the measured or estimated absolute acceleration. The calculated maximum absolute acceleration is integrated over two floors to obtain the absolute displacement, from which the inter-story displacement is calculated, and the maximum inter-story deformation angle during the time of earthquake occurrence is calculated from the inter-story displacement and the floor height. These values ​​are then used to determine the condition of the building.

[0088] [State Determination Processing] FIG. 11 is a diagram for explaining the determination regarding the state of a building.

[0089] The condition of a building is judged for each part of the building. In the judgment for each part, at least one of the maximum absolute acceleration and the maximum inter-story drift angle during the time of the earthquake is used as the judgment value. Specifically, as shown in FIG. 11(A), the maximum inter-story drift angle is used to judge the condition of the building structure, the maximum absolute acceleration and the maximum inter-story drift angle are used to judge the condition of the piping equipment, the maximum absolute acceleration is used to judge the condition of the ceiling, and the maximum inter-story drift angle is used to judge the condition of the exterior wall material. Note that the ceiling also includes lighting fixtures.

[0090] In addition, in the judgment for each part, as shown in Fig. 11(B), first, the judgment target value is compared with a predetermined first threshold value. If the judgment target value is less than the first threshold value, it is judged as "safe", while if the judgment target value is equal to or greater than the first threshold value, it is next compared with a predetermined second threshold value. Then, if the judgment target value is less than the second threshold value, it is judged as "inspection required (caution required)", while if the judgment target value is equal to or greater than the second threshold value, it is judged as "dangerous".

[0091] 12 is a flowchart showing an example of the procedure of the state determination process (step S40 in FIG. 4). The example of the procedure will be described below.

[0092] Step S41: First, the state determination unit 34 sets a floor to be determined (hereinafter, referred to as a "target floor").

[0093] Step S42: The state determination unit 34 executes a structural frame determination process for the target floor. In this process, the state determination unit 34 compares the maximum inter-storey deformation angle of the target floor with a first threshold value TF1 and a second threshold value TF2, which are predefined for determining the structural frame with respect to the maximum inter-storey deformation angle, along the flow shown in FIG. 11 (B), and determines whether the floor is "safe," "requires inspection (caution)," or "dangerous."

[0094] Step S43: The state determination unit 34 executes a plumbing equipment determination process for the target floor. In this process, the state determination unit 34 compares the absolute acceleration of the target floor with a first threshold value TP1k and a second threshold value TP2k, which are predefined for the determination of plumbing equipment for the maximum absolute acceleration, along the flow shown in FIG. 11B, and compares the maximum inter-storey deformation angle of the target floor with a first threshold value TP1s and a second threshold value TP2s, which are predefined for the determination of plumbing equipment for the maximum inter-storey deformation angle. If the absolute acceleration of the target floor is less than the first threshold value TP1k and the maximum inter-storey deformation angle of the target floor is less than the first threshold value TP1s, it is judged as "safe," if the absolute acceleration of the target floor is less than the second threshold value TP2k and the maximum inter-storey deformation angle of the target floor is less than the second threshold value TP2k, it is judged as "requires inspection (caution)," and in other cases, i.e., if the absolute acceleration of the target floor is equal to or greater than the second threshold value TP2k or the maximum inter-storey deformation angle of the target floor is equal to or greater than the second threshold value TP2s, it is judged as "dangerous."

[0095] Step S44: The state determination unit 34 executes a ceiling determination process for the target floor. In this process, the state determination unit 34 compares the absolute acceleration of the target floor with a first threshold value TC1 and a second threshold value TC2, which are predefined for determining the ceiling with respect to the maximum absolute acceleration, along the flow shown in (B) of Fig. 11, and determines whether the floor is "safe", "inspection required (caution required)", or "dangerous".

[0096] Step S45: The state determination unit 34 executes exterior wall material determination processing for the target floor. In this processing, the state determination unit 34 compares the maximum inter-storey deformation angle of the target floor with a first threshold value TW1 and a second threshold value TW2, which are predefined for determining the exterior wall material for the maximum inter-storey deformation angle, along the flow shown in FIG. 11 (B), and determines whether the floor is "safe," "requires inspection (caution)," or "dangerous."

[0097] Step S46: The state determination unit 34 checks whether all floors have been determined, and if all floors have not been determined, that is, if there are floors that have not been determined (Step S46: No), the state determination unit 34 returns to Step S41 and repeats the subsequent steps. On the other hand, if all floors have been determined (Step S46: Yes), the state determination unit 34 ends the state determination process.

[0098] [Notification of Determination Result] FIG. 13 is a diagram showing a determination result screen generated by the notification processor 35 and displayed on the display 36 in the determination result notification process (step S50 in FIG. 4), as an example of a notification mode of the determination result.

[0099] The judgment result screen is roughly divided into three areas: the left side, the right side, and the bottom side. On the left side of the screen, the floors where accelerometers are installed in building BL (1st floor, 3rd floor, 6th floor, rooftop) are indicated with black circles, and the seismic intensity on those floors is shown, along with the distribution of maximum absolute acceleration and maximum absolute displacement during the time of the earthquake on each floor, which are displayed in graphs. The black dots plotted on each graph indicate actual measured values, and the white dots indicate estimated values.

[0100] In addition, the right part of the screen visually displays the degree of damage to each floor, estimated based on the maximum absolute acceleration and maximum story drift angle during the time of the earthquake on each floor. Specifically, for example, the boundaries of each floor are represented by shapes (circles, squares, triangles), and the boundaries are represented by lines, and these shapes and lines are represented in different ways depending on the state of each building part. A filled circle and a solid line indicate a safe state, a filled square and a shaded line indicate a state requiring caution (inspection), and a filled triangle and a dashed line indicate a dangerous state. In the actual screen, the filled circle and solid line indicating safety are displayed in green, the filled square and shaded line indicating caution are displayed in yellow, and the filled triangle and dashed line indicating danger are displayed in red.

[0101] In the example shown, there are no signs indicating danger, but the section of the structure from the 1st to 5th floors and the section of the exterior wall material from the 2nd to 4th floors are both indicated by a hatched line (yellow), which indicates that the areas corresponding to these sections, i.e., the structure on the 1st, 2nd, 3rd, and 4th floors and the exterior wall material on the 2nd and 3rd floors, require inspection.

[0102] The bottom of the screen shows an overall assessment of the condition of the building. As mentioned above, in the illustrated example, the building frames (columns) on the 1st, 2nd, 3rd, and 4th floors and the exterior wall materials on the 2nd and 3rd floors require inspection, so in the overall assessment, the [Building] column states "Inspection required. Please be careful" as the assessment of the entire building, and the [Caution required] column states "Building frames (columns) on the 1st, 2nd, 3rd, and 4th floors, exterior wall materials on the 2nd and 3rd floors." Note that there are no signs indicating danger, so there are no entries in the [Danger] column.

[0103] By displaying the assessment results in this manner, the user can intuitively grasp the condition of each floor at a glance, and can also confirm the condition of each floor from the text information. Also, because both the figures and line types are different depending on the condition, the user can reliably identify the damage level of each part from the differences in the figures and line types, even if the assessment result screen is printed out in black and white.

[0104] According to the damage extent estimation system 1 of the above-described embodiment, the following effects can be obtained. (1) In the acceleration recording synchronization process (Fig. 5), the correlation function of the absolute displacements of the two accelerometers is calculated, and the step number at which the correlation function reaches its peak value near step number 0 is identified as the deviation step. However, since the correlation function of the absolute displacement has only one point at which it reaches its peak value (maximum correlation) near step number 0, the deviation step can be uniquely identified. As a result, it is possible to accurately identify the deviation in the internal times of the two accelerometers and properly synchronize the absolute acceleration records recorded by both.

[0105] (2) In the acceleration record synchronization process (Fig. 5), in the case of a mid- to high-rise building, in addition to the first correction performed for each accelerometer using the correlation function of absolute displacement, a second correction is performed to adjust the transmission time of the earthquake in the vertical direction. This makes it possible to bring the time of recordings by each accelerometer obtained by the first correction closer to the accurate time when those records were actually made.

[0106] (3) In the acceleration estimation process (Fig. 8), cubic spline interpolation is performed using records from multiple accelerometers installed in the building and building height information to estimate the time history of absolute acceleration on floors where accelerometers are not installed. This eliminates the need to analyze the target building in advance, and enables efficient estimation of absolute acceleration.

[0107] (4) In the acceleration estimation process (Fig. 8), two boundary conditions are set and two types of cubic spline interpolation are performed, and the results are added together in a predetermined ratio determined in advance based on verification. This makes it possible to accurately estimate the absolute acceleration during the time of earthquake occurrence on each floor where an accelerometer is not installed.

[0108] (5) For each floor on which an accelerometer is installed, actual measured values ​​are used, while for floors on which an accelerometer is not installed, the maximum absolute acceleration and maximum story deformation angle during the time of the earthquake are calculated using estimated values ​​obtained by adding together the results of two types of cubic spline interpolation in a specified ratio. These values ​​are used to determine the condition of the building for each part of the building, allowing for accurate and efficient determinations.

[0109] (6) Since there is no need to conduct a prior analysis of the target building, the installation of accelerometers and the introduction of the damage estimation system can be carried out easily.

[0110] The present invention is not limited to the above-described embodiment, and can be practiced in various modified forms.

[0111] In the above embodiment, a wireless accelerometer 10 is installed, but if the environment permits, a wired accelerometer can also be installed. In that case, if the internal time of each accelerometer is routinely synchronized with the on-site computer 30, there is no need to execute the acceleration record synchronization process (step S10 in FIG. 4; FIG. 5).

[0112] In the above-described embodiment, the building is divided into four parts, namely, the structure, the plumbing equipment, the ceiling, and the exterior wall materials, and the condition of each part is judged, but the building may be divided into more parts and the judgment may be made.

[0113] In the above-described embodiment, all the functions of the damage extent estimation system 1 are implemented in the on-site computer 30. However, if the network bandwidth is wide and a certain level of communication speed is ensured, it is also possible to implement the functions of the damage extent estimation system 1 in the management server 50 or other computers connected to the network 40 instead of the on-site computer 30.

[0114] In addition, all of the embodiments shown in the drawings are merely preferred examples, and it goes without saying that suitable modifications are possible when implementing the present invention. [Explanation of symbols]

[0115] 1. Damage Estimation System 10 Accelerometer 20 Receiver 30 Local Computer 40 Network BL Building

Claims

1. a record synchronizing means for synchronizing the recording of absolute acceleration by a plurality of accelerometers installed at the top end, the bottom end, and at least two other locations according to a predetermined rule on the ground portion of the building; an acceleration estimation means for performing cubic spline interpolation on the absolute acceleration at each time during the time zone during which an earthquake occurs based on the absolute acceleration records from the plurality of accelerometers after synchronization and the height of the building, and estimating the absolute acceleration during the time zone during which an earthquake occurs on each floor on which an accelerometer is not installed from the result of the cubic spline interpolation; a condition determination means for determining a maximum absolute acceleration and a maximum inter-story drift angle during an earthquake occurrence time period on each ground floor of the building based on the absolute acceleration recorded on each floor on which an accelerometer is installed and the absolute acceleration estimated on each floor on which an accelerometer is not installed, and for determining a condition of each upper floor by comparing the maximum absolute acceleration and the maximum inter-story drift angle with respective preset threshold values; a result notification means for notifying the status of each upper floor at least by displaying the screen; A damage estimation system equipped with

2. 2. The damage extent estimation system according to claim 1, The plurality of accelerometers include A damage extent estimation system characterized in that, when the rigidity modulus of the building is 0.6 or greater, the remaining accelerometers are installed on floors located at positions that divide the height between the upper end and the lower end approximately equally, while, when the rigidity modulus of the building is less than 0.6, accelerometers are first installed at the upper end and the lower end, and above and below floors where the rigidity modulus is less than 0.6, and the remaining accelerometers are installed on floors located at positions that divide the height between the upper end or the lower end and the nearest floor on which an accelerometer is installed approximately equally.

3. In the damage extent estimation system according to claim 2, The plurality of accelerometers include A damage extent estimation system characterized in that, if the eccentricity ratio of the building exceeds 0.15, an accelerometer is installed near the exterior wall on the side farther away from the center of rigidity.

4. 2. The damage extent estimation system according to claim 1, The acceleration estimation means A damage estimation system characterized in that, as boundary conditions for cubic spline interpolation, a first condition is set under which the first derivative is zero at the upper end point corresponding to the recorded value at the upper end and at the lower end point corresponding to the recorded value at the lower end, and a second condition is set under which the third derivative at the upper end point and the lower end point are the same as those at adjacent points, and the absolute acceleration during the time of earthquake occurrence on each floor where an accelerometer is not installed is estimated from the result of adding together the results of two types of cubic spline interpolation calculated under the first condition and the second condition in a predetermined ratio.

5. 2. The damage extent estimation system according to claim 1, The recording synchronization means includes: A damage extent estimation system characterized by calculating a correlation function with a step number corresponding to the difference in time at which the absolute acceleration was recorded by the two accelerometers as a variable for the absolute displacement at the location where each accelerometer is installed, which is calculated by second-order integration of the absolute acceleration recorded by two of the multiple accelerometers during the time when the earthquake occurred, and identifying the step number at which the correlation function reaches its peak value immediately adjacent to step number 0 and multiplying this step number by the recording time interval, thereby identifying the time difference between the two accelerometers.

6. An installation step of installing one accelerometer each at an upper end, a lower end, and at least two other locations in accordance with a predetermined rule on a ground portion of the building; an interpolation process in which, as boundary conditions for cubic spline interpolation of absolute acceleration at each time of an earthquake occurrence time zone based on the height of the building and the records of absolute acceleration by the multiple accelerometers, a first condition is set under which a first derivative is zero at an upper end point corresponding to a recorded value at the upper end and at a lower end point corresponding to a recorded value at the lower end, and a second condition is set under which a third derivative at the upper end point and the lower end point is the same as that at adjacent points, and an interpolation process in which two types of cubic spline interpolation are performed based on the first condition and the second condition; an estimation means for estimating the absolute acceleration during the time period when the earthquake occurs on each floor on which an accelerometer is not installed, based on a result of adding up the results of the two types of cubic spline interpolation at a predetermined ratio; The acceleration estimation method includes:

7. 7. The acceleration estimation method according to claim 6, In the installation step, An acceleration estimation method characterized in that, when the rigidity modulus of the building is 0.6 or greater, the remaining accelerometers are installed on floors located at positions that divide the height between the upper end and the lower end approximately equally, while, when the rigidity modulus of the building is less than 0.6, accelerometers are first installed at the upper end and the lower end, and above and below floors where the rigidity modulus is less than 0.6, and the remaining accelerometers are installed on floors located at positions that divide the height between the upper end or the lower end and the nearest floor on which an accelerometer is installed approximately equally.

8. 8. The acceleration estimation method according to claim 7, In the installation step, The acceleration estimation method is characterized in that, when the eccentricity ratio of the building exceeds 0.15, an accelerometer is installed near the outer wall on the side farther away from the center of rigidity.

9. On the computer, an interpolation procedure in which, as boundary conditions for cubic spline interpolation of absolute acceleration at each time of an earthquake occurrence time zone, which is performed based on absolute acceleration records from a plurality of accelerometers installed, one at each of the top end and bottom end of the above-ground portion of a building, and at least two other locations in accordance with a predetermined rule, and the height of the building, a first condition is set under which a first derivative is zero at an upper end point corresponding to a recorded value at the top end and a lower end point corresponding to a recorded value at the bottom end, and a second condition is set under which a third derivative at the upper end point and the lower end point is the same as that at adjacent points, and two types of cubic spline interpolation are performed based on the first and second conditions; and estimating the absolute acceleration during the time of earthquake occurrence on each floor where an accelerometer is not installed from the result of adding up the results of the two types of cubic spline interpolation at a predetermined ratio. An acceleration estimation program that executes the above.

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