Earthquake response evaluating method and earthquake response evaluating system based on tremor measurement

Abstract

To estimate an earthquake response at an arbitrary position of a building.SOLUTION: An earthquake response evaluating method has steps of: obtaining tremor information D1 related to microtremor generated in a building 200, by using a plurality of vibration sensors 2 installed at respective measurement points in the building 200 S1; obtaining oscillation characteristic information D21 including a natural period, a damping ratio, an oscillation mode and a stimulus coefficient of the building 200, by using the tremor information D1 S21; obtaining a measurement point response D22 generated at the measurement points when the building 200 receives assumed earthquake motion, by using the oscillation characteristic information D21 S22; and obtaining an estimation point response D32 generated at an estimation point which does not overlap the measurement points in the building 200, from a plurality of measurement point responses D22 by using a spatial interpolation estimation method S4.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention relates to an earthquake response evaluation method and an earthquake response evaluation system based on microtremor measurement. [Background technology]

[0002] Non-Patent Document 1 describes an earthquake response evaluation method that can evaluate the earthquake response at measurement points by measuring microtremors inside a building. In this evaluation method, first, sensors are installed at multiple points inside a building and microtremor measurements are performed to obtain acceleration data at each measurement point. Next, the acquired acceleration data is used to identify the natural period, vibration mode shape, and damping constant, and further the stimulation coefficient is roughly calculated. Finally, the earthquake response at the measurement points where microtremor measurements were performed can be evaluated by modal analysis using the natural period, vibration mode shape, damping constant, and stimulation coefficient, assuming the earthquake motion input to the building. [Prior art documents] [Non-patent literature]

[0003] [Non-Patent Document 1] Xie, Jinzhe, Ikeda, Yoshiki, and Kurata, Masahiro, "Construction of a multi-degree-of-freedom linear building model for earthquake response analysis based on microtremor measurements," Journal of Structural Engineering, Japan, Architectural Institute of Japan, March 2021, vol.67B, pp.509-518. Summary of the Invention [Problem to be solved by the invention]

[0004] The technology of Non-Patent Document 1 predicts the response when a hypothetical earthquake motion is input to a building. More specifically, the technology of Non-Patent Document 1 predicts the earthquake response at the position where a sensor for measuring microtremors is installed. In other words, the technology of Non-Patent Document 1 cannot predict the earthquake response that occurs at any point in a building.

[0005] Therefore, the present invention provides an earthquake response evaluation method and an earthquake response evaluation system that can estimate the earthquake response at any location of a building. [Means for solving the problem]

[0006] One form of the present invention is [1] "a method for evaluating earthquake response comprising: a first step of obtaining microtremor information related to microtremors occurring in a building using a plurality of vibration sensors respectively installed at measurement points on the building; a second step of obtaining vibration characteristic information of the building using the microtremor information, the vibration characteristic information including the natural period, damping ratio, vibration mode, and stimulation coefficient of the building; a third step of obtaining measurement point responses occurring at the measurement points when the building is subjected to an assumed earthquake motion using the vibration characteristic information; and a fourth step of obtaining an estimated point response occurring at an estimated point in the building that does not overlap with the measurement points from the plurality of measurement point responses using a spatial interpolation estimation method."

[0007] In one embodiment of the earthquake response estimation method, vibration characteristic information is obtained by using microtremor information obtained by executing a step of obtaining microtremor information. This vibration characteristic information makes it possible to obtain earthquake responses at a plurality of measurement points when an assumed earthquake motion is input to a building. Then, this earthquake response estimation method sets estimation points that do not overlap with the measurement points, and obtains the estimation point responses at the estimation points using a spatial interpolation estimation method. In other words, this earthquake response estimation method can estimate the earthquake response at any point on the building.

[0008] One embodiment of the earthquake response evaluation method may be the earthquake response evaluation method described in [1] above, [2] "The fourth step includes a step of determining whether or not a virtual straight line connecting the estimation point and the measurement point overlaps with an opening formed in a floor of the building, and attaching identification information indicative of the determination result to the measurement point response, and a step of obtaining the estimation point response from a plurality of the measurement point responses attached with the identification information indicating that they do not overlap with the opening." In this case, as a result of performing the step of adding the identification information to the measurement point response, it is possible to distinguish between the measurement point response in which the virtual straight line overlaps with the opening for each estimation point and the measurement point response in which the virtual straight line does not overlap with the opening. In other words, in the step of obtaining the estimation point response, the estimation point response can be obtained using only the measurement point responses in which the virtual straight line does not overlap with the opening. As a result, it is possible to eliminate the measurement point response in which the virtual straight line overlaps with the opening for each estimation point, which may affect the accuracy of the estimation point response. Therefore, it is possible to obtain a more accurate estimation point response.

[0009] One embodiment of the earthquake response evaluation method may be the earthquake response evaluation method described in [1] or [2] above, [3] "wherein the first step includes a step of installing a plurality of the vibration sensors in the building and a step of obtaining the microtremor information using the plurality of the vibration sensors installed in the building, and in the step of installing the vibration sensors, the plurality of the vibration sensors are installed on at least one of the main beams and the minor beams that constitute the building." In this case, since the vibration sensor is installed on at least one of the main beam and the minor beam, micro-motion information that is less affected by walking vibrations that can become noise can be obtained compared to when the vibration sensor is installed in a location other than the main beam and the minor beam. By using this micro-motion information, more accurate vibration characteristic information can be obtained. As a result, more accurate estimated point responses can be obtained.

[0010] One embodiment of the earthquake response evaluation method may be the earthquake response evaluation method described in any one of [1] to [3] above, [4] "wherein the first step includes a step of installing a plurality of the vibration sensors in the building and a step of obtaining the microtremor information using the plurality of the vibration sensors installed in the building, and in the step of installing the vibration sensors, the vibration sensors are positioned around the periphery of an opening formed in a floor of the building." When the vibration sensor is installed on the periphery of the opening, the earthquake response occurring at the position of the vibration sensor installed on the periphery of the opening can be used to obtain the estimated point response occurring at the estimated point around the other opening, so that the estimated point response around the opening can be obtained with high accuracy.

[0011] Another form of the present invention is [5] "an earthquake response evaluation system comprising: a plurality of vibration sensors respectively installed at measurement points on a building to obtain microtremor information related to constant microtremors occurring in the building; and an information processing unit which uses the microtremor information to obtain an estimated point response occurring at an estimated point not overlapping with the measurement points in the building when the building is subjected to an assumed earthquake motion, wherein the information processing unit uses the microtremor information to obtain vibration characteristic information including the natural period, damping ratio, vibration mode, and stimulation coefficient of the building, and also includes a measurement point response acquisition unit which uses the vibration characteristic information to obtain the measurement point response occurring at the measurement point when the building is subjected to an assumed earthquake motion, and an estimation point response acquisition unit which uses a spatial interpolation estimation method to obtain the estimated point response occurring at the estimation point not overlapping with the measurement point in the building from the plurality of measurement point responses." Another type of earthquake response evaluation system also sets estimation points that do not overlap with the measurement points, and obtains the estimation point response at the estimation points using a spatial interpolation estimation method. In other words, this earthquake response evaluation system can estimate the earthquake response at any point on the building.

[0012] Another form of the earthquake response evaluation system may be [6] "the earthquake response evaluation system described in [5] above, wherein the estimation point response acquisition unit determines whether or not a virtual straight line connecting the estimation point and the measurement point overlaps with an opening formed in a floor of the building, and includes an identification information assignment unit that assigns identification information indicating the determination result to the measurement point response, and an interpolation calculation unit that obtains the estimation point response from a plurality of the measurement point responses to which the identification information indicating that they do not overlap with the opening has been assigned." According to the identification information assigning unit, as a result of performing the step of assigning identification information to the measurement point responses, it is possible to distinguish between measurement point responses in which the virtual straight line overlaps with the opening for each estimated point and measurement point responses in which the virtual straight line does not overlap with the opening. As a result, the interpolation calculation unit can obtain the estimated point response using only the measurement point responses in which the virtual straight line does not overlap with the opening. Therefore, it is possible to eliminate the measurement point responses in which the virtual straight line overlaps with the opening for each estimated point, which may affect the accuracy of the estimated point response. Therefore, it is possible to obtain a more accurate estimated point response. Effect of the Invention

[0013] According to the present invention, it is possible to provide an earthquake response evaluation method and an earthquake response evaluation system capable of estimating the earthquake response at any point of a building. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a functional block diagram of an earthquake response evaluation system according to an embodiment. [Diagram 2] FIG. 2 is a diagram for explaining the arrangement of the vibration sensors and the process of attaching the identification information. [Diagram 3] FIG. 3 is a diagram showing a physical configuration of the information processing device shown in FIG. [Figure 4] FIG. 4 is a flowchart showing main steps of earthquake response evaluation according to the embodiment. [Diagram 5] FIG. 5(a) is a schematic diagram explaining the process of obtaining microtremor information, FIG. 5(b) is a schematic diagram explaining the process of obtaining measurement point responses, and FIG. 5(c) is a schematic diagram explaining the process of obtaining estimated point responses. [Figure 6] FIG. 6 is a flow chart showing in detail the process of attaching the identification information shown in FIG. [Figure 7] FIG. 7 is a flow chart detailing the steps for obtaining the estimated point responses shown in FIG. [Figure 8] 8(a) and (b) are contour diagrams showing the earthquake response evaluation results of the example. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In the description of the drawings, the same elements are given the same reference numerals, and duplicated explanations will be omitted.

[0016] The earthquake response evaluation system 1 shown in Fig. 1 and the earthquake response evaluation method shown in Fig. 4 are applied to the evaluation of a building 200. The building 200 has multiple floors. For example, the building 200 has a foundation floor, a rooftop, and multiple intermediate floors. For example, an opening 201a is formed in a floor 201 of the building 200 to form an open-ceiling space. In addition, "evaluation" in the following description refers to obtaining the earthquake response that occurs in the building 200 when the building 200 is subjected to a hypothetical earthquake motion.

[0017] [Earthquake response evaluation system] As shown in FIG. 1, the earthquake response evaluation system 1 includes a plurality of vibration sensors 2, an information collecting device 3, and an information processing device 10 (information processing unit). The plurality of vibration sensors 2 are installed in a building 200. The plurality of vibration sensors 2 acquire microtremor information D1 related to constant microtremors occurring in the building 200. The microtremor information D1 includes at least one of a time history of acceleration, a time history of velocity, and a history of displacement. Furthermore, the microtremor information D1 may include information for identifying the position where the vibration sensor 2 is placed. The plurality of vibration sensors 2 output the acquired microtremor information D1 to the information collecting device 3. The information collecting device 3 temporarily stores the microtremor information D1. The information collecting device 3 outputs the microtremor information D1 to the information processing device 10. The information collecting device 3 may output the microtremor information D1 in response to a request from the information processing device 10. The information collecting device 3 may output the microtremor information D1 when a predetermined time has elapsed without responding to a request from the information processing device 10. The information collecting device 3 may be omitted as necessary. In this case, the information processing device 10 may substitute for the function of the information collecting device 3. The information processing device 10 acquires estimated point information D3 of a desired position in the building 200 by using the microtremor information D1. The information processing device 10 presents the acquired estimated point information D3 of the desired position to the user via the output device 4.

[0018] 2, the multiple vibration sensors 2 may be installed throughout the building 200. The multiple vibration sensors 2 may be installed on main beams 202 or on minor beams 203 that constitute the building 200. When the building 200 has an opening 201a in a floor 201 for forming an open-ceiling space, the multiple vibration sensors 2 may be disposed on the edge of the opening 201a in the floor 201.

[0019] [Information processing device 10] The hardware configuration of the information processing device 10 will be described with reference to Fig. 3. The information processing device 10 is configured by a computer 100. The computer 100 has a processor 101 which is a CPU (Central Processing Unit), a main memory unit 102, an auxiliary memory unit 103, an external communication unit 104, an operation unit 105, and an output unit 106. The information processing device 10 is configured by one or more computers 100 which are configured by these hardware units and software such as programs.

[0020] When the information processing device 10 is composed of a plurality of computers 100, these computers 100 may be connected locally or via a communication network such as the Internet or an intranet. This connection logically constructs one information processing device 10.

[0021] The processor 101 executes an operating system, application programs, etc. The main memory unit 102 is composed of a ROM (Read Only Memory) and a RAM (Random Access Memory). The auxiliary memory unit 103 is a storage medium composed of a hard disk, a flash memory, etc. The auxiliary memory unit 103 generally stores a larger amount of data than the main memory unit 102. At least a part of each unit constituting the information processing device 10 is realized by the auxiliary memory unit 103. At least a part of each unit constituting the information processing device 10 may be realized by an external communication unit 104. The operation unit 105 is composed of a keyboard, a mouse, a touch panel, a microphone for voice input, etc.

[0022] The auxiliary storage unit 103 stores in advance a program P for estimating an earthquake response and data necessary for processing. The processor 101 executes the program P for estimating an earthquake response to realize each functional element of the information processing device 10. The program P for estimating an earthquake response may be provided in a state recorded on a tangible recording medium such as a CD-ROM, a DVD-ROM, or a semiconductor memory. The program P for estimating an earthquake response may be provided as a data signal via a communication network.

[0023] Referring again to Fig. 1, the information processing device 10 has a recording unit 11, a measurement point response acquisition unit 12, and an estimation point response acquisition unit 13. The recording unit 11 is a physical component, such as an auxiliary storage unit 103. The measurement point response acquisition unit 12 and the estimation point response acquisition unit 13 are functional components, and are realized by the processor 101 executing a program P that estimates an earthquake response.

[0024] The recording unit 11 temporarily stores data output from the information collecting device 3, the measurement point response acquisition unit 12, and the estimation point response acquisition unit 13. The recording unit 11 outputs the stored data to the measurement point response acquisition unit 12 and the estimation point response acquisition unit 13 in response to requests from the measurement point response acquisition unit 12 and the estimation point response acquisition unit 13.

[0025] The measurement point response acquisition unit 12 obtains, by calculation, a response occurring at the position where the vibration sensor 2 is placed when a hypothetical earthquake motion is applied to the building 200. In the following description, the position where the vibration sensor 2 is placed is referred to as a "measurement point", and the response occurring at the measurement point is referred to as a "measurement point response D22". Furthermore, a data set including the measurement point response D22, the coordinates of the measurement point, and other incidental information as information related to the measurement point is referred to as "measurement point information D2". The measurement point response acquisition unit 12 has a vibration characteristic information calculation unit 121 and a measurement point response calculation unit 122, which are functional components.

[0026] <Vibration characteristic information calculation section> The vibration characteristic information calculation unit 121 obtains vibration characteristic information D21 for obtaining a measurement point response D22 by calculation. The vibration characteristic information D21 includes, for example, a natural period, a damping ratio, and a stimulation coefficient. In this embodiment, the vibration characteristic information D21 may also include vibration mode information. The vibration characteristic information calculation unit 121 receives micromotion information D1 from the recording unit 11. The vibration characteristic information calculation unit 121 obtains vibration characteristic information D21 using the micromotion information D1. The vibration characteristic information calculation unit 121 outputs the vibration characteristic information D21 to the recording unit 11.

[0027] A specific calculation method for obtaining the vibration characteristic information D21 using the multiple pieces of microtremor information D1 can be a combination of known methods. For example, a so-called FDD method (Frequency Domain Decomposition method) can be used as a specific calculation method for obtaining the vibration characteristic information D21.

[0028] The measurement point response calculation unit 122 obtains the measurement point response D22 by calculation. The measurement point response calculation unit 122 obtains the measurement point response D22 as a superposition of modal responses at each measurement point. The modal response can be obtained by solving an equation of motion including the vibration characteristic information D21 and ground acceleration (assumed earthquake motion).

[0029] The measurement point response calculation unit 122 receives the vibration characteristic information D21 and the calculation equation information D23 including an equation defining the superposition of modal responses and an equation of motion from the recording unit 11. The measurement point response calculation unit 122 obtains the measurement point response D22 using the vibration characteristic information D21 and the calculation equation information D23. The measurement point response calculation unit 122 outputs the measurement point response D22 to the recording unit 11.

[0030] The vibration characteristic information calculation unit 121 described above can also estimate the measurement point response D22 occurring in the building 200 when a hypothetical earthquake is applied to the building 200. However, the position at which the response can be estimated is the measurement point where the vibration sensor 2 is disposed. In other words, the vibration characteristic information calculation unit 121 cannot estimate a position that does not overlap with the measurement point, in other words, a response occurring at an arbitrary position in the building 200. Therefore, the earthquake response evaluation system 1 of this embodiment has an estimated point response acquisition unit 13 for estimating a response occurring at an arbitrary position.

[0031] <Estimated point response acquisition section> The estimation point response acquisition unit 13 acquires a response of a desired position in the building 200 by using the measurement point information D2. In the following description, the desired position in the building 200 is referred to as an "estimated point," and the response occurring at the estimated point is referred to as an "estimated point response D32." Furthermore, a data set including the estimated point response D32, the coordinates of the estimated point, and other incidental information as information related to the estimated point is referred to as "estimated point information D3."

[0032] The estimated point response acquisition unit 13 obtains predetermined estimated point information D3 from a plurality of measurement point information D2 using a spatial interpolation estimation method. The spatial interpolation estimation method obtains an estimated point response D32 by multiplying the measurement point response D22 by a predetermined weight and adding them together. The predetermined weight may be, for example, in accordance with the distance from a certain estimated point to one measurement point. The weight may be calculated using, for example, an inverse distance weighting method. For such calculation, the estimated point response acquisition unit 13 has an interpolation calculation unit 132.

[0033] Incidentally, an opening 201a may be provided in a floor 201 of a building 200 to form an atrium or the like. As shown in FIG. 2, the influence of vibrations generated at each measurement point on an estimated point is considered. For example, when a certain measurement point P1 is connected to an estimated point PS by a virtual line L1, the virtual line L1 always passes through the floor 201. Similarly, when another measurement point P2 is connected to an estimated point PS by a virtual line L2, the virtual line L2 always passes through the floor 201. In other words, it is considered that vibrations generated at certain measurement points P1 and P2 will have a significant influence on the estimated point PS by transmitting through the floor 201 along the virtual lines L1 and L2.

[0034] On the other hand, when the other measurement point P3 is connected to the estimated point PS by a virtual line L3, a part of the virtual line L3 passes through the opening 201a. The opening 201a does not transmit vibrations like the floor 201. Therefore, it can be considered that the vibrations generated at the other measurement point P3 affect the estimated point PS via the structural members surrounding the opening 201a, or do not have a significant effect on the estimated point PS in the first place. In other words, depending on the structure between the measurement point P3 and the estimated point PS, there is a possibility that the measurement point response D22 that is originally less affected or has no effect may be included in the calculation of the estimated point response D32. Therefore, by excluding the measurement point response D22 that is less affected or has no effect from the calculation of the estimated point response D32, it is possible to improve the accuracy of the estimated point response D32. It is also possible to reduce the calculation load. For such calculations, the estimated point response acquisition unit 13 has an identification information assignment unit 131. The identification information assigning unit 131 is a process for extracting information for obtaining the estimated point response D32 before the calculation of the estimated point response D32, and therefore the identification information assigning unit 131 can also be called a pre-processing unit.

[0035] The estimation point response acquisition unit 13 described below first assigns, to each of the measurement point information D2, identification information indicating whether or not each of the measurement point responses D22 is to be used in the calculation of the estimation point response D32 by the identification information assignment unit 131. Then, in the estimation point response acquisition unit 13, the interpolation calculation unit 132 acquires the estimation point response D32 by using a spatial interpolation method based on the identification information.

[0036] The operation of adding the identification information by the identification information adding unit 131 may be performed as necessary. For example, when high accuracy of estimation is not required, the operation of adding the identification information by the identification information adding unit 131 may be omitted.

[0037] The identification information adding unit 131 and the interpolation calculation unit 132 will be described in detail below.

[0038] <Identification information assignment section> The identification information assigning unit 131 receives a plurality of measurement point information D2, an estimated point information D3 indicating one estimated point, and information D4 indicating the structure of the building 200 from the recording unit 11. The information D4 indicating the structure of the building 200 includes at least information indicating the position of the opening 201a. Note that the information indicating the position of the estimated point included in the estimated point information D3 may be specified by the user via an input device each time a calculation is performed. The identification information assigning unit 131 evaluates whether or not the opening 201a exists between the estimated point corresponding to the specified position and the plurality of measurement points. Then, the identification information assigning unit 131 assigns identification information (tag) indicating the presence of the opening 201a or identification information indicating the absence of the opening 201a to each of the measurement point information D2. For example, "1" may be assigned as identification information indicating the presence of the opening 201a, and "0" may be assigned as identification information indicating the absence of the opening 201a. Then, the identification information assigning unit 131 outputs the plurality of measurement point information D2 to which the identification information has been assigned to the recording unit 11.

[0039] The procedure of assigning identification information to the measurement point information D2 performed by the identification information assigning unit 131 will be described. First, for example, a virtual line L1 is drawn between the measurement point P1 and the estimated point PS. Next, it is determined whether the virtual line L1 overlaps with the opening 201a. This determination may be performed using any algorithm. Since the virtual line L1 does not overlap with the opening 201a of the floor 201, the identification information assigning unit 131 assigns identification information (0) indicating that the opening 201a does not exist to the measurement point information D2. On the other hand, when the virtual line L1 overlaps with the opening 201a of the floor 201 as shown by the virtual line L3, the identification information assigning unit 131 assigns identification information (1) indicating that the opening 201a exists to the measurement point information D2.

[0040] <Interpolation calculation section> The interpolation calculation unit 132 first receives a plurality of pieces of measurement point information D2 and estimation point information D3 indicating one estimation point from the recording unit 11. Next, the interpolation calculation unit 132 uses the plurality of pieces of measurement point information D2 to which identification information (0) indicating that the opening 201a does not exist to obtain an estimation point response D32 at the estimation point using a spatial interpolation estimation method. The spatial interpolation estimation method obtains the estimation point response D32 by adding together the measurement point response D22 multiplied by a weight. Then, the interpolation calculation unit 132 outputs the estimation point information D3 including the estimation point response D32 to the recording unit 11.

[0041] As an example of the calculation, when the inverse distance weighting method is used, the interpolation calculation unit 132 obtains the estimated point response D32 in the following procedure. First, the interpolation calculation unit 132 obtains the square of the distance D from a certain measurement point to the estimated point. Next, using equations (1) and (2), it obtains a weight to be multiplied by the measurement point response D22. Then, using equation (3), it adds up the measurement point response D22 multiplied by the weight. Note that in the following equation, D i is explained as the square of the distance between the measurement point and the estimation point, but D i may simply be the distance.

number

number

number

[0042] [Earthquake response evaluation method] Next, an explanation will be given of the earthquake response evaluation method, which is the operation of the above-mentioned earthquake response evaluation system 1. Fig. 4 is a flowchart showing the main steps of the earthquake response evaluation method.

[0043] First, microtremor measurement is performed on the building 200 (step S1: first step). In step S1, microtremor information D1 related to microtremors occurring in the building is obtained. Step S1 is executed by multiple vibration sensors 2 and information collection device 3. First, in step S1, multiple vibration sensors 2 are installed in the building 200 in a state where no earthquake is occurring (step S11, see Figures 2 and 5(a) etc.). Microtremor information D1 caused by minute vibrations occurring constantly in the building 200 is obtained (step S12). The microtremor measurement is performed for about one to several days. It is preferable to perform the microtremor measurement at night when there is little walking vibration that can become measurement noise.

[0044] Next, the obtained microtremor information D1 is used to obtain vibration characteristic information D21 (step S2: second step). Step S2 may include a process of obtaining the natural period, the damping ratio, and the vibration mode (step S21), and a process of approximately evaluating the stimulation coefficient (S22). Step S2 is executed by the vibration characteristic information calculation unit 121. Next, the vibration characteristic information D21 is used to obtain a measurement point response D22 (step S3: third step, see FIG. 5(b)). Step S3 is executed by the measurement point response calculation unit 122.

[0045] Next, the estimated point response D32 is obtained using a spatial interpolation estimation method (step S4: fourth step, see FIG. 5(c)). Step S4 is executed by the estimated point response acquisition unit 13. Step S4 includes a process of adding identification information (step S41) and a process of obtaining the estimated point response D32 using the spatial interpolation estimation method (step S42).

[0046] <Process of adding identification information: Step S41> Step S41 is executed by the identification information assigning unit 131. As shown in Fig. 6, step S41 includes steps S411 to S418.

[0047] First, the identification information assigning unit 131 obtains the coordinates of the estimated point (n) from the recording unit 11 (step S411). Here, "n" is a counter for distinguishing between the respective estimated points when multiple estimated points are specified. Next, the identification information assigning unit 131 obtains the coordinates of the measurement point (i) from the recording unit 11 (step S412). Here, "i" is a counter for distinguishing between the multiple measurement points. The counter (i) for controlling the measurement point may be the number of vibration sensors 2 installed on the floor 201. Next, the identification information assigning unit 131 draws a virtual line connecting the estimated point (n) and the measurement point (i) on the plan view (step S413).

[0048] Next, the identification information assigning unit 131 judges whether the virtual line L overlaps the opening 201a of the floor 201 (step S414). If the result of the judgment in step S414 is that the virtual line L does not overlap the opening 201a of the floor 201 (step S414: NO), the identification information assigning unit 131 assigns identification information indicating that the virtual line L does not overlap the opening 201a to the measurement point response D22(i) (step S415). If the result of the judgment in step S414 is that the virtual line L overlaps the opening 201a of the floor 201 (step S414: YES), the identification information assigning unit 131 proceeds to the next step S416.

[0049] Then, the identification information assigning unit 131 counts up the counter (i) of the measurement point (step S416). Next, the identification information assigning unit 131 determines whether the counter (i) of the measurement point has reached a maximum value (step S417).

[0050] If the counter (i) that controls the measurement point has not reached the maximum value (step S417: NO), the identification process of the multiple measurement point responses D22 for the estimated position (n) is not complete. Therefore, the identification process (steps S412 to S417) of the next measurement point response D22(i+1) is executed.

[0051] When the counter (i) that controls the measurement point reaches the maximum value (step S417: YES), it can be said that the identification process of the multiple measurement point responses D22 for the estimated position (n) is completed. Therefore, the counter (n) that controls the estimated position is counted up. Then, the processes of steps S411 to S418 are executed for the next estimated position (n+1).

[0052] <Process for obtaining estimated point response: Step S42> Step S42 is executed by the interpolation calculation unit 132. As shown in FIG. 7, step S42 includes steps S421 to S426. First, the interpolation calculation unit 132 reads the coordinates of the estimation point (n) from the recording unit 11 (step S421). Next, the interpolation calculation unit 132 reads the first to Ith measurement point responses D22 from the recording unit 11 (step S422). The measurement point responses D22 read in step S422 include coordinate information of the measurement points (i to I) and identification information corresponding to the estimation point (n), in addition to information related to earthquake response in the narrow sense, such as the time history of acceleration, the time history of velocity, and the time history of displacement.

[0053] Next, the interpolation calculation unit 132 extracts, from the multiple measurement point responses D22(i to I) that have been read, those that have identification information indicating that no opening 201a exists between the estimation point (n) and the measurement point (i) (step S423).

[0054] Next, the interpolation calculation unit 132 obtains the square of the distance D from the estimation point for each of the extracted measurement point responses D22 (step S424). Next, a weighting coefficient is obtained for each measurement point using the square of the distance D corresponding to each of the measurement point responses D22 (step S425, see formula (2)). Then, the estimated point response D32 is obtained by obtaining the sum of values ​​obtained by multiplying the measurement point responses D22 by the weighting coefficients (step S426, see formula (3)).

[0055] [Effects] The earthquake response evaluation method includes step S1 of obtaining microtremor information D1 regarding constant microtremors occurring in the building 200 using a plurality of vibration sensors 2 respectively installed at measurement points in the building 200, step S21 of obtaining vibration characteristic information D21 including the natural period, damping ratio, vibration mode and stimulation coefficient of the building 200 using the microtremor information D1, step S22 of obtaining a measurement point response D22 occurring at the measurement point when the building 200 is subjected to an assumed earthquake motion using the vibration characteristic information D21, and step S4 of obtaining an estimated point response D32 occurring at an estimated point in the building 200 that does not overlap with the measurement point from the plurality of measurement point responses D22 using a spatial interpolation estimation method.

[0056] The earthquake response estimation method obtains vibration characteristic information D21 by using the microtremor information D1 obtained by executing step S1 for obtaining the microtremor information D1. This vibration characteristic information D21 makes it possible to obtain earthquake responses at a plurality of measurement points when an assumed earthquake motion is input to the building 200. Then, this earthquake response estimation method sets estimation points that do not overlap with the measurement points, and obtains estimation point responses D32 at the estimation points using a spatial interpolation estimation method. In other words, this earthquake response estimation method can estimate earthquake responses at any point of the building 200.

[0057] Step S4 of obtaining an estimated point response includes step S41 of determining whether a virtual straight line connecting the estimated point and the measurement point overlaps with an opening 201a formed in a floor 201 of the building 200, and assigning identification information indicating the determination result to the measurement point response D22, and step S42 of obtaining an estimated point response D32 from the multiple measurement point responses D22 assigned identification information indicating that they do not overlap with the opening 201a.

[0058] In this case, as a result of performing step S41 of adding identification information to the measurement point response D22, it is possible to distinguish between the measurement point response D22 in which the virtual straight line overlaps the opening 201a for each estimated point and the measurement point response D22 in which the virtual straight line does not overlap the opening 201a. That is, in step S4 of obtaining the estimated point response D32, the estimated point response D32 can be obtained using only the measurement point response D22 in which the virtual straight line does not overlap the opening. As a result, it is possible to eliminate the measurement point response D22 in which the virtual straight line overlaps the opening 201a for each estimated point that may affect the accuracy of the estimated point response D32. Therefore, it is possible to obtain a more accurate estimated point response D32.

[0059] The step of obtaining the micromotion information D1 includes a step S11 of installing a plurality of vibration sensors 2 in the building 200, and a step S12 of obtaining the micromotion information D1 using the plurality of vibration sensors 2 installed in the building 200. In the step S11 of installing the vibration sensors 2, the plurality of vibration sensors 2 are installed on at least one of the main beam 202 and the minor beam 203 that constitute the building 200.

[0060] In this case, since the vibration sensor 2 is installed on at least one of the main girder 202 and the minor beam 203, it is possible to obtain micro-motion information D1 that is less affected by walking vibrations, which can become noise, compared to a case in which the vibration sensor 2 is installed in a location other than the main girder 202 and the minor beam 203. By using this micro-motion information D1, it is possible to obtain more accurate vibration characteristic information D21. As a result, it is possible to obtain more accurate estimated point response D32.

[0061] The step of obtaining micro-motion information D1 includes a step S11 of installing multiple vibration sensors 2 in building 200, and a step S12 of obtaining micro-motion information D1 using the multiple vibration sensors 2 installed in building 200, and in the step of installing the vibration sensors 2, the vibration sensors 2 are positioned on the periphery of an opening 201a formed in a floor 201 of the building 200.

[0062] When the vibration sensor 2 is installed on the periphery of the opening 201a, the earthquake response occurring at the position of the vibration sensor 2 installed on the periphery of the opening 201a can be used to obtain the estimated point response D32 occurring at the estimated point of another opening 201a. Therefore, the estimated point response D32 in the periphery of the opening 201a can be obtained with high accuracy.

[0063] The earthquake response evaluation system 1 includes a plurality of vibration sensors 2 that are installed at measurement points in a building 200 and obtain microtremor information D1 related to microtremors occurring in the building 200, and an information processing device 10 that obtains, using the microtremor information D1, estimated point responses occurring at estimated points not overlapping with the measurement points in the building 200 when the building 200 is subjected to an assumed earthquake motion. The information processing device 10 includes a measurement point response acquisition unit 12 that obtains vibration characteristic information D21 including the natural period, damping ratio, vibration mode, and stimulation coefficient of the building 200 using the microtremor information D1, and obtains, using the vibration characteristic information D21, measurement point responses D22 occurring at the measurement points when the building 200 is subjected to an assumed earthquake motion, and an estimated point response acquisition unit 13 that obtains, from the plurality of measurement point responses D22, an estimated point response D32 occurring at estimated points not overlapping with the measurement points in the building 200 using a spatial interpolation estimation method.

[0064] The earthquake response evaluation system 1 also sets an estimation point that does not overlap with the measurement point, and obtains an estimation point response D32 at the estimation point by using a spatial interpolation estimation method. In other words, the earthquake response evaluation system 1 can estimate the earthquake response at any point of the building 200.

[0065] The estimated point response acquisition unit 13 includes an identification information assignment unit 131 that determines whether a virtual straight line connecting the estimated point and the measurement point overlaps with an opening 201a formed in a floor 201 of a building 200, and assigns identification information indicating the determination result to the measurement point response, and an interpolation calculation unit 132 that obtains an estimated point response D32 from a plurality of measurement point responses D22 that are assigned identification information indicating that they do not overlap with the opening 201a.

[0066] The identification information assigning unit 131 can distinguish between the measurement point response D22 in which the virtual straight line overlaps the opening for each estimated point and the measurement point response D22 in which the virtual straight line does not overlap the opening. As a result, the interpolation calculation unit 132 can obtain the estimated point response D32 using only the measurement point response D22 in which the virtual straight line does not overlap the opening 201a. Therefore, it is possible to eliminate the measurement point response D22 in which the virtual straight line overlaps the opening 201a for each estimated point, which may affect the accuracy of the estimated point response D32. Therefore, it is possible to obtain a more accurate estimated point response D32.

[0067] [Example] 8(a) and 8(b) show earthquake response estimation results of an embodiment of the earthquake response analysis method described above. In the embodiment, the earthquake response analysis method shown in steps S1 to S4 was carried out. The hypothetical earthquake input to the building 300 has a seismic motion equivalent to level 2, and is 0.5 times the announcement wave in which the phase of the seismic wave is a random number phase. Several openings 302 are formed in a floor 301 of the building 300. The openings 302 are areas where stairs are provided or areas where elevators are provided.

[0068] Fig. 8(a) is a contour diagram showing the distribution of maximum acceleration responses along the X direction. Fig. 8(b) is a contour diagram showing the distribution of maximum acceleration responses along the Y direction. The density of the hatching corresponds to the magnitude of the acceleration. The narrower the hatching interval, the greater the acceleration.

[0069] The earthquake response analysis method of this embodiment can obtain the acceleration response occurring at any position, so that contour diagrams such as those shown in FIG. 8(a) and FIG. 8(b) can be obtained. Referring to FIG. 8(a) and FIG. 8(b), it can be seen that the distribution of the acceleration response is not affected by the positions of the components of the building 300, such as columns and beams, or the positions of the sensors, and that the estimated point responses at any positions throughout the floor 301 can be obtained. In addition, it can be seen that the result of the maximum acceleration response along the X direction is distributed over the entire plane at the same level of response acceleration compared to the result of the maximum acceleration response along the Y direction. From this, it can be seen that the rigid floor assumption is more likely to be established in the X direction than in the Y direction for the building 300 of the embodiment. In addition, as shown in FIG. 8(b), it was found that in the Y direction, the maximum acceleration response on the right side of the building 300 is greater than the maximum acceleration response on the left side of the building 300. From this result, it can be inferred that the area on the right side of FIG. 8(b) is an area with a high earthquake risk.

[0070] Knowing the response at any point in the entire building is believed to have the following advantages and effects. First, the user can visually grasp the building behavior, making it easy to understand even for general users who do not have much knowledge of vibration analysis. Also, it is possible to create an internal building hazard map linked to an earthquake hazard map that shows the strength of an earthquake. Furthermore, it is possible to determine areas where the rigid floor assumption can be established, which can be useful in selecting inspection points for building surveys after earthquake damage. For example, in the results of Figure 8(b), it is preferable to select the area on the right side of the figure, where the response in the Y direction is large, as the inspection point.

[0071] [Variations] The earthquake response evaluation system 1 and the earthquake response evaluation method of the present invention are not limited to the above-described embodiment, and various modifications are possible without departing from the gist of the present invention.

[0072] In the above embodiment, the multiple vibration sensors 2 are installed on the main beam and the minor beam, but they do not have to be installed. The multiple vibration sensors 2 do not have to be arranged on the periphery of the opening 201a of the floor 201. The process of attaching the identification information (step S41) may be skipped. [Explanation of symbols]

[0073] 1...earthquake response evaluation system, 2...vibration sensor, 10...information processing device (information processing unit), 12...measurement point response acquisition unit, 13...estimated point response acquisition unit, 131...identification information assignment unit, 132...interpolation calculation unit, 200...building, 201...floor, 201a...opening, 202...main beam, 203...minor beam, D1...microtremor information, D2...measurement point information, D3...estimated point information, D21...vibration characteristic information.

Claims

1. A first step of acquiring microtremor information related to microtremors occurring in a building using a plurality of vibration sensors respectively installed at measurement points in the building; a second step of obtaining vibration characteristic information including a natural period, a damping ratio, a vibration mode, and an excitation coefficient of the building using the microtremor information; a third step of obtaining, by using the vibration characteristic information, a measurement point response that occurs at the measurement point when the building is subjected to an assumed earthquake motion; and a fourth step of obtaining an estimated point response occurring at an estimated point in the building that does not overlap with the measurement point from the multiple measurement point responses using a spatial interpolation estimation method.

2. The fourth step is determining whether or not a virtual straight line connecting the estimation point and the measurement point overlaps with an opening formed in a floor of the building, and attaching identification information indicating the determination result to the measurement point response; The earthquake response evaluation method according to claim 1 , further comprising a step of obtaining the estimated point response from a plurality of the measurement point responses to which the identification information indicating that the measurement point responses do not overlap with the opening is attached.

3. The first step comprises: installing a plurality of said vibration sensors in said building; obtaining the microtremor information using a plurality of the vibration sensors installed in the building; 3. The earthquake response evaluation method according to claim 1, wherein in the step of installing the vibration sensors, a plurality of the vibration sensors are installed on at least one of a main beam and a minor beam that constitute the building.

4. The first step comprises: installing a plurality of said vibration sensors in said building; obtaining the microtremor information using a plurality of the vibration sensors installed in the building; 3. The earthquake response evaluation method according to claim 1, wherein in the step of installing the vibration sensors, the vibration sensors are disposed on a periphery of an opening formed in a floor of the building.

5. A plurality of vibration sensors are installed at measurement points in a building to obtain microtremor information related to microtremors occurring in the building; an information processing unit that uses the microtremor information to obtain an estimated point response that occurs at an estimated point that does not overlap with the measurement point in the building when the building is subjected to an assumed earthquake motion, The information processing unit includes: a measurement point response acquisition unit that acquires vibration characteristic information including a natural period, a damping ratio, a vibration mode, and a stimulation coefficient of the building by using the microtremor information, and acquires a measurement point response that occurs at the measurement point when the building is subjected to a hypothetical earthquake motion by using the vibration characteristic information; and an estimation point response acquisition unit that acquires an estimation point response occurring at an estimation point in the building that does not overlap with the measurement point from a plurality of the measurement point responses using a spatial interpolation estimation method.

6. The estimation point response acquisition unit is an identification information assigning unit that determines whether or not a virtual line connecting the estimation point and the measurement point overlaps with an opening formed in a floor of the building, and assigns identification information indicating a result of the determination to the measurement point response; The earthquake response evaluation system according to claim 5 , further comprising: an interpolation calculation unit that obtains the estimated point response from a plurality of the measurement point responses to which the identification information indicating that the measurement point responses do not overlap with the opening is attached.

Images