JP3510616B2 - Method and system for diagnosing structures by microtremor observation - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and system for diagnosing a structure, which evaluates the safety and soundness of a structure which is a natural or artificial structure.

[0002]

2. Description of the Related Art Structures (structures, artifacts such as structures,
Assessing and diagnosing the safety and soundness of grounds, cliffs, rocks, trees, and other natural objects) is necessary for disaster prevention, maintenance of structures, intermediate / complete inspections at the time of new renovation of structures, and sudden earthquakes. It is required for pre and post measures against external force. For example, assessing the risk of structures being destroyed by the effects of seismic motion includes quality inspection after new construction and renovation, maintenance and management of existing structures, development of repair plans, availability of damaged structures, and reinforcement. Or it is important in determining the need for demolition. The quality of the structure is difficult to evaluate and control, unlike products that are mass-produced in a factory.

In particular, sudden external force (earthquake, typhoon, explosion, etc.)
Evaluating the risk of destruction due to the action of, there is uncertainty in the nature and magnitude of the external force, and it is not possible to perform a test to actually apply the external force of the earthquake to the structure,
It is extremely difficult due to changes in quality due to aging and usage conditions.

Conventionally, when a structure is an artificial one, the safety and soundness of the structure and the risk of the structure being destroyed by the action of seismic motion are evaluated as follows: (1) During construction or completion Immediately after that, a method of visually confirming that the structure is constructed as specified in the design drawing, or a method of hitting the structure to determine a hitting sound, (2) a design drawing of the structure or , The structural drawing created by the current situation survey, the concrete strength obtained by the core removal inspection, the information such as the age of the structure, etc. are integrated, and the results of the structural calculation are aggregated, and the structural seismic index (Is) and cumulative strength index CT The method of diagnosing by calculating the shape index SD and comparing the magnitude of these with the reference value of the result of analyzing past earthquake disaster cases is standardized and widely used by the Japan Building Disaster Prevention Association.

When a structure is damaged by an earthquake,
(3) A method called urgent damage level judgment is also widely used, in which the degree of damage to structural members, residual deformation of structures, etc. are entered on a check sheet by visual inspection, and the safety of structures is diagnosed by the score calculated from this. There is.

Further, (4) a method of mounting an exciter on a structure to forcibly generate elastic waves and the like, and (5) evaluation using infrared rays naturally emitted from the structure Method, (6) evaluation method using X-rays or electromagnetic waves,
(7) A method in which a geophone is installed in a structure and evaluation is performed using microtremor observation is used.

As an evaluation method using microtremor observation,
(8) A method of considering the maximum value (predominant period) of the Fourier amplitude spectrum of the micromotion data of the structure measured by the geophone as the natural period of the structure (soil or structure) and using this as an evaluation index, ( 9) There is a method in which the result calculated using the ratio of the Fourier spectra of the vertical movement portion and the horizontal movement portion of the fine movement speed time history and the size of the structure is used as the evaluation index. Also,
(10) Considering that the spectral ratio calculated by the method of (9) or the Fourier spectral ratio of two observation time history components is a transfer function, the maximum vibration of the structure at a plurality of observation points during an earthquake A method of predicting values and calculating the numerical values such as the maximum value of the interlayer deformation angle necessary for diagnosing a structure by further calculating these predicted values using geometric conditions such as the size and shape of the structure There is.

[0008]

However, the method of (1) above is premised on that the design standard gives the structure sufficient strength against the action of an earthquake. 1,000 built before the revision of the standards
More than 10,000 buildings are judged to have insufficient seismic resistance according to current standards. Moreover, since the human senses such as visual and auditory senses are used, there is a problem that depends on subjective judgment.

In the above method (2), if the drawings or measured values used as the information source do not sufficiently reflect the current state of the actual structure, the obtained index does not represent the actual safety, There are problems that it takes time and cost, that there is room for subjectivity in determining the aging deterioration index value, and that it is not suitable for monitoring subtle secular changes in the structure's seismic resistance.

The above method (3) may rely on subjective judgment because the visual inspection is the main focus. Also,
Originally, the seismic resistance of a structure depends on the magnitude of the target earthquake motion, but the methods (2) and (3) above are not methods that clearly reflect this.

The above method (4) is costly and time consuming, and it is technically and economically difficult to make the energy of the forced vibration by the exciter large enough to determine the response characteristics of the structure. In many cases, the examples are limited to special structures such as bridges. Moreover, it cannot be said that the degree of influence on the structure is completely eliminated by forcibly causing the elastic wave. In addition, the physical effect of forced excitation on a specific point of the structure is different from when the actual seismic force is input from the boundary surface of the structure.

The methods of (5) and (6) above are information from a part of the surface of the structure, etc., and in order to obtain an amount of information sufficient for general diagnosis of the soundness of the structure, etc. The problem is that it costs a lot of money and time.

In the method (8) of the method (7) using the microtremor observation, the correlation between the predominant period and the safety of the structure should be used for the safety evaluation both theoretically and statistically. Is not as high as possible, and the problem is that the accuracy is low.
In both the methods (8) and (9), the Fourier spectrum depends on the measurement parameter and has many irregularities, and the determination of this maximum value may have to rely on the subjectivity, which is not an objective index. What is important is that it is difficult to automate the determination. The method of (10) above calculates the time history such as the interlayer deformation angle from the time history and the geometric conditions such as the size of the structure, and the calculation of the statistical index such as the maximum value with respect to the time history. Except for a very special case, the operation to be performed generally has a different result by changing the order and loses its physical meaning, so that there is a problem that it is not suitable for use in diagnosis.

Conventionally, microtremor observation has been carried out for the purpose of measuring the natural vibration period of the ground or structure rather than using it for diagnosis and evaluation of safety and soundness. Therefore, the measuring instrument has the function of displaying the time history and spectrum of the observation data, but in order to analyze the microtremor observation data in detail, it is necessary to bring back the data and perform calculation and plotting. The cost was a problem.

When a structure such as a building is to be diagnosed, it is recognized that it is important to consider the influence of rotation in the current seismic design calculation and in the analysis of past disaster cases, and it is executed. However, none of the above-mentioned conventional methods directly calculates or measures the rotation of the structure.

The present invention has been made in view of such problems, and an object thereof is to make a simple, quick and inexpensive diagnosis of safety and soundness of a structure which is a natural or artificial structure. Another object of the present invention is to provide a diagnosis method and a diagnosis system.

[0017]

A first aspect of the present invention for achieving the above-mentioned object is, when a fine movement is applied to a structure,
As a parameter indicating the transfer characteristic of the structure, a scalar quantity called an energy transfer rate (RMS ratio) is calculated, an attention time history is calculated from an observation time history, and the energy transfer rate (RMS ratio) is calculated as an observation time history. Alternatively, it is a method of diagnosing a structure, which is calculated as a ratio of root mean square (RMS) between directional components of the time history of interest. In the first invention, the energy transfer rate (R
Calculate the MS ratio). In addition, the time history of interest is calculated from the time history of microtremor observation. Also, the energy transfer rate (RMS ratio)
Is calculated as the ratio of the root mean square (RMS) values between the directional components of the observation time history or the attention time history.

A second aspect of the present invention is to observe minute movements of a structure, and consider that the power spectrum of the minute movement time history or the attention time history is such that an unexpected external force acts on the structure and the structure behaves elastically. In this case, the observation time zone is selected so as to be substantially similar to the power spectrum of the time history that occurs in the structure in the above case. Second
In the invention of, the power spectrum of the fine movement time history or the attention time history of the structure is the power spectrum of the time history generated in the structure when it is considered that the structure behaves elastically due to the sudden external force acting on the structure. Select the observation time zones so that they are almost similar.

A third aspect of the invention is to calculate a scalar quantity called an energy transfer rate (RMS ratio) as an index representing a transfer characteristic of the structure when a slight movement is applied to the structure.
A structure characterized by calculating an attention time history from an observation time history, and calculating the energy transfer rate (RMS ratio) as a ratio of a root mean square value (RMS) between directional components of the observation time history or the attention time history. It is a diagnostic system for things. Third
In the invention, there is a calculating means for carrying out the first invention.

In a fourth aspect of the present invention, it is considered that minute movements of a structure are observed, and that the power spectrum of the minute movement time history or the attention time history is such that an unexpected external force acts on the structure and the structure behaves elastically. In this case, the observation time zone is selected so as to be substantially similar to the power spectrum of the time history that occurs in the structure in the above case.
The fourth aspect of the invention has a calculating means and the like for executing the second aspect of the invention.

A fifth aspect of the invention is a step of calculating a physical quantity of interest from a microtremor observation value observed from a structure, a step of calculating an energy transfer rate (RMS ratio) using the physical quantity of interest, and the energy transfer rate. (RMS ratio) and the expected energy transfer rate (RMS ratio) originally expected for the structure, and a step of determining the state of the structure by the comparison. It is a method of diagnosing a structure. In the fifth invention, the physical quantity of interest is calculated from the microtremor observation value of the micromotion added to the structure, the energy transfer rate (RMS ratio) is further calculated from the physical quantity of interest, and the energy transfer rate (RMS ratio) expected for the structure is calculated. ), The soundness of the structure is diagnosed.

According to a sixth aspect of the present invention, there is provided a step of calculating a physical quantity of interest from a microscopic observation value observed from a structure, a step of calculating an energy transfer rate (RMS ratio) using the physical quantity of interest, and the structure. The predicted maximum value of the physical quantity of interest is calculated from the step of predicting the maximum displacement of the observation point or the plane of the structure when it is assumed that a sudden external force is applied, and the energy transfer rate (RMS ratio) and the maximum displacement. The method for diagnosing a structure is characterized by comprising: In the sixth aspect, the physical quantity of interest is calculated from the micromotion observation value of the micromotion added to the structure, and the energy transfer rate (RMS ratio) is calculated from the physical quantity of interest. In addition, the maximum displacement of the observation point or plane when it is assumed that a sudden external force is applied to the structure is predicted, and the predicted maximum value of the physical quantity of interest is calculated from the energy transfer rate (RMS ratio) to determine the safety of the structure. It is used as an index to diagnose sex.

A seventh aspect of the invention comprises a plurality of geophones installed at an observation point or a plane of the structure, a measuring instrument and a computer, wherein the geophones measure micromotion applied to the structure. Sent to the measuring device, the measuring device sends the microtremor observation value to the computer, the computer,
Means for calculating a physical quantity of interest from the microtremor observation value, means for calculating an energy transfer rate (RMS ratio) using the physical quantity of interest, the energy transfer rate (RMS ratio), and the structure originally expected. Expected energy transfer rate (RMS
Ratio), and a means for judging the state of the structure by the comparison, the diagnostic system for the structure. The diagnostic system of the seventh invention is a diagnostic system for realizing the diagnostic method of the fifth invention.

An eighth aspect of the present invention comprises a plurality of geophones installed at an observation point or a plane of the structure, a measuring instrument and a computer, wherein the geophones measure fine movements applied to the structure. Sent to the measuring device, the measuring device sends the microtremor observation value to the computer, the computer,
Means for calculating a physical quantity of interest from the microtremor observation value, means for calculating an energy transfer rate (RMS ratio) using the physical quantity of interest, and the observation point or plane when it is assumed that a sudden external force is applied to the structure. And a means for predicting a maximum displacement of the target physical quantity from the energy transfer rate (RMS ratio) and the maximum displacement. Is. The diagnostic system of the eighth invention is a diagnostic system for realizing the diagnostic method of the sixth invention.

A ninth aspect of the present invention comprises means for calculating a physical quantity of interest from a microtremor observation value, means for calculating an energy transfer rate (RMS ratio) using the physical quantity of interest, and the energy transfer rate (RMS ratio), A computer comprising: a means for comparing an expected energy transfer rate (RMS ratio) originally expected for the structure; and a means for determining the state of the structure by the comparison. The computer of the ninth invention realizes the diagnosis method of the fifth invention.

In a tenth aspect of the present invention, means for calculating a physical quantity of interest from a microtremor observation value, means for calculating an energy transfer rate (RMS ratio) using the physical quantity of interest, and a sudden external force applied to the structure. A means for predicting the maximum displacement of the observation point or the plane when the energy transfer rate (RM)
S ratio) and the maximum displacement, and means for calculating the predicted maximum value of the physical quantity of interest, the computer. The computer of the tenth invention realizes the diagnosis method of the sixth invention.

An eleventh invention provides a computer as claimed in claim 2.
A program characterized by causing it to function as the computer according to claim 28. The program of the eleventh invention causes a computer to function as the computer according to the twentieth to twenty-eighth aspects, and the program can be distributed via a network.

A twelfth invention is a recording medium recording the program according to claim 29. The recording medium of the twelfth invention stores the program according to claim 29, and this recording medium can be distributed, or this program can be distributed via a network.

The structures are artificial structures such as embankments, retaining walls, dams, revetments, bridges, piers, and buildings.
The safety and soundness of the object is to be diagnosed, but in the present specification, natural objects such as ground, bedrock, cliffs, rocks and trees are also included.

Microtremor is a minute vibration that is constantly occurring in the structure. This vibration energy is naturally input from the boundary surface between the structure and the outside world regardless of the action of the observer. From the surface in contact with air, the effect of wind, from the boundary in contact with water due to waves and tides, and from the boundary in contact with other structures due to the action of other structures, Vibration energy is supplied from the contacting boundary due to the influence of traffic vibration and the like. In high-rise buildings, towers, chimneys, bridges located on rivers and coasts, most of the energy of microtremors is constantly supplied by wind, water currents and waves. Therefore, it is difficult to estimate the impact of the earthquake by microtremor in these structures. However, when placed in ordinary structures such as wooden houses and middle-rise reinforced concrete buildings, most of the energy of microtremor is always present in the ground and structures, except under special environmental conditions such as strong wind and rain. Since it can be considered that the input is from the boundary, the displacement of the structure when the earthquake motion acts can be calculated from the information obtained by the microtremor observation. In addition, even in high-rise buildings, it is possible to estimate the displacement when a seismic motion is applied by selecting the observation time zone in which it is considered that the vibration energy is mainly input from the boundary between the ground and the structure.

The observation point is a point set by an observer inside or on the surface of the structure, and indicates a position where a geophone is installed to observe the displacement time history and the like. For the observation time history, use a geophone installed at the observation point to receive microscopic movements of the structure as analog vibrations of the time history of displacement, velocity, acceleration, etc., and perform AD conversion to record this as digital time history. It is the time history obtained by. The observation time zone is the time band (start time, end time,
Say duration). The observation frequency band is a frequency band determined by the characteristics of the geophone, the signal sampling frequency, and the like, and the observation time history is considered to be the actual displacement or speed. The analysis time zone is a subset of the observation time zone, and is the time zone for calculating the observation time history. The analysis frequency band is a subset of the observation frequency band, and is the frequency band for calculating the observation time history.

The safety means that the structure is partially or totally destroyed due to a sudden external force such as an earthquake, a large wind, or a wave, or due to aged action such as deterioration. Point Soundness refers to whether all or part of the structure has the expected properties or qualities in the light of design documents, other survey results, empirical rules, etc.

The physical quantity of interest is the kinematics of interest in diagnosis,
A quantity in terms of elastic mechanics or structural mechanics, which is the point inside a structure, the displacement or relative displacement of a plane, or the relative rotation angle between points inside a structure or between planes, or the average compressive strain inside a structure, the average It is the amount of shear strain, average bending strain, average torsion strain, and the like. The attention time history is the observation time history, the coordinates of the observation point,
It is the time history of the physical quantity of interest calculated from the dimensions of the structure.

The reference point is an observation point installed near the boundary surface between the structure and the outside world, and is a point used as a reference for measuring the inflow amount of the vibration energy flowing into the structure from the outside world.
The reference plane is a plane having the same role as the above-mentioned reference point.

The layer of the structure is a part of the structure which can be considered as one when describing the deformable property of the structure. For example, in the case of a building, the structural parts composed of floors, beams and columns, and walls on each floor are usually called layers. In the case of structures such as viaducts on the Shinkansen or conventional lines in the form of concrete ramen, layers can consist of structural parts composed of beams and columns at approximately the same height from the ground surface. Even in the ground, it is common practice to describe the deformation properties by considering the strata having almost the same mechanical characteristics as a structural layer as one. Layers are given numbers, thicknesses, coordinates, and mechanical properties such as shear stiffness and damping constant, and attributes such as displacement and velocity are defined inside the layers and at the boundaries, and these are used as physical quantities of interest. .

The boundaries between the layers consist of horizontal and vertical planes in a typical structure. Usually, it is assumed that the layer boundary surface is not deformed, and the deformation of the structure occurs inside the layer and can be described by the relative displacement between the layer boundary surfaces. Generally, the displacement of the layer boundary is a time history with time as a parameter, and a total of three components of horizontal two components and vertical components in the translation direction,
Rotational components can be considered around the same three directions. Interlayer displacement is the relative displacement between the boundaries of layers. The inter-layer deformation angle is a value obtained by dividing the relative displacement in two horizontal translations between layer boundaries by the thickness of the layer, and relates to the mechanical properties of structural elements (members) forming the layer, safety against fracture, etc. Most research results are organized using interlayer displacement or interlayer deformation angle as an index. By using the observation plane as the layer boundary surface of the structure and using the average strain as the physical quantity of interest, it is possible to easily compare it with the calculation results by other methods such as dynamic structure analysis.

The energy transfer rate is a scalar quantity representing the vibration transfer characteristic in the structure. The energy transfer rate (RMS
Ratio) is the ratio of the root mean square value of observation time histories defined on the same time zone to the root mean square value (RMS) of other observation time histories. When the time histories of both are considered to be the input and output of the linear system, the transfer characteristics in the sense that the root mean square value (RMS) of the outputs is given to any input that is similar to the power spectrum of the input time history. Will be an indicator of. Usually, a denominator is a mean square value of observation time history with a reference point or a reference plane.

The reference estimated displacement amount is the maximum displacement amount that is estimated to occur at the reference point or the reference surface due to the action of a sudden external force taken into consideration when evaluating the safety of the structure.

Prior to evaluating the risk of structural damage due to an earthquake, first, the structure is investigated in advance, and the layer describing the deformation of the structure and the reference plane to which the seismic force is input are determined.
Corresponding to this, the installation position of the geophone (micromotion meter) is determined. Next, microtremor data (velocity time history or displacement time history) is constantly recorded by the installed geophone (micromotion meter), and from this data, relative displacement time history between boundary surfaces, rotation angle time history, reference surface Displacement time histories are calculated and their Fourier spectra are calculated. In general, the theory of linear systems can be used to calculate the response to any input given that the structure behaves linearly from the relationship between the input and output Fourier spectra.

The method of the present invention is based on the following four assumptions regarding microtremor. (1) Since the type and size ratio of the source of vibration energy from the outside that constantly causes microtremor can be estimated from the characteristics and environment of the structure, the observation time zone can be changed according to the environmental conditions. If you select it and select the analysis time band and analysis frequency band according to the characteristics of the structure, one type of vibration energy is predominant, and the observation time that can be considered to be incident from a certain boundary surface. You can get a history. (2) Microtremor has an amplitude of 1 to
Since it is as small as about 10 microns, it is possible to describe the response of a structure by the theory of micro-deformation elastic vibration and linear systems, regardless of the structure.
(3) From the characteristics and environment of the structure, it is possible to predict in advance the surface on which a sudden external force such as an earthquake or storm will enter, and from this surface, the energy of a small external force of the same kind as the sudden external force can be constantly predicted. It is incident. (4) There is an observation time zone in which the power spectrum of the minute movement displacement time history of the reference point or the reference surface generated by the minute constant external force corresponding to the sudden external force is similar to each other. Therefore, by selecting the observation time zone or the like from the above, it is possible to perform fine movement observation in which a minute external force corresponding to the sudden external force is predominant. Further, in the method of the present invention, the response of a structure to seismic motion is simply calculated by using the following assumption that is usually made in designing a structure. That is, (1) each component of the response of the structure is independent of each other.
(2) A structure exhibits non-linearity with respect to a large external force such as a large earthquake, but it is called the constant energy law from the response calculated assuming that the structure behaves linearly for the maximum response at this time. It can be calculated using assumptions. (3) The displacement of the structure, which is always caused by the slight movement, is minute. Furthermore, in this method, (4) the microtremor spectrum observed at the layer boundary near the ground of the structure will be observed when the ground and the structure behave linearly in a large earthquake. Is assumed to be similar to.

[0041]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. First, the diagnostic system 1 will be described. FIG. 1 is a configuration diagram of the diagnostic system 1. As shown in FIG. 1, the diagnostic system 1 includes a geophone 5,
It is composed of a measuring instrument 7, a computer 9, and the like. Geophone 5
-1, the geophone 5-2, and the geophone 5-3 are arranged on each layer boundary surface 3-1, the layer boundary surface 3-2, and the layer boundary surface 3-3 for observing the fine movement of the structure 21. Geophone 5-1, geophone 5-2,
The geophone 5-3 and the measuring instrument 7 are connected by a cable 11, and the measuring instrument 7 and the computer 9 are connected by a cable 13.

Geophone 5-1, Geophone 5-2, Geophone 5-
3 measures the absolute velocity and displacement at that point. Geophone 5-
1, the geophone 5-2 and the geophone 5-3 are, for example, GE
An O / SPACE MPU3-4 or the like is used, and an AD converter and an amplifier are used as the measuring device 7. The geophone 5 and the measuring instrument 7 can be housed in the same case, but in this case, the vibration and noise of the instrument 7 should not be detected by the geophone 5.

FIG. 2 is a flowchart of conversion of data collected by the diagnostic system 1. As shown in FIG. 2, in the diagnostic system 1, the geophone 5 is used to measure the micromotion, that is, the vibration of the layer boundary surface 3 (step 201).
The analog data such as the displacement and the velocity waveform collected in step 3 are obtained (step 202). This analog data is cable 1
1 to the measuring instrument 7 for digital conversion (step 203) to obtain digital data (step 20).
4). This digital data is transmitted to the computer 9 via the cable 13 to calculate the interlayer displacement 73, the rotation angle 83, etc. (step 205).

The data processing in the computer 9 in step 205 does not require complicated numerical operation such as repetitive calculation and convergence calculation. Ordinary spreadsheet software as software (such as Microsoft Excel (trademark))
Use the built-in functions of, or create a simple program in a programming language such as C to perform calculations.

As described above, by using the diagnostic system 1, it is possible to carry out from the measurement of the fine movement data of the structure 21 to the calculation of the numerical index in a short time and at low cost.
The cable 11 and the cable 13 may be wireless communication means. For example, the Internet is connected via a modem or the like. Alternatively, a method of carrying data by a floppy disk or the like may be used.

Further, the measuring device 7 and the computer 9 are not limited to being installed in the building, but may be housed in the same case or may be remote from each other. In the former case, the result can be obtained immediately at the measurement location. In the latter case, data for multiple buildings can be processed simultaneously. Even in the latter case, if the calculation result is transmitted to the display device of the measuring instrument and displayed, the result can be immediately obtained at the measurement point. in this way,
Since the observation result can be evaluated immediately, the observation point can be changed and the observation time zone can be changed by moving the geophone 5.

Next, the diagnostic method will be described with reference to the flowchart of the diagnostic method shown in FIG. 3 by taking the structure 21 shown in FIGS. 5 and 6 as an example. First, the structure 21 is preliminarily investigated to determine the installation position of the geophone 5 and the reference plane 25 (step 303). FIG. 4 is a schematic diagram of the vibration and structure 21 to be evaluated. Generally, as shown in FIG. 4, the reference surface 25 is a layer boundary surface of the layer 27-4 near the ground surface 23 input by the microtremor 29 or the earthquake motion 31. In addition, the layer 27 that describes the deformation of the structure 21 is selected, and the adjacent layer 2 is selected.
The installation position of the geophone 5 is determined on the layer boundary surface 3 of 7.

In the diagnostic example, the geophone 5 is installed at the position shown in FIGS. 5 and 6 are installation positions of the geophone 5 in the diagnosis example. The geophone 5 is installed near the center between the layer boundary surface 3-2 on the intermediate floor, the layer boundary surface 3-5, and the reference surface 25. In addition, the layer boundary surface 3- of the rooftop floor (RF)
1, the three geophones 5-1-1 and 5 are diagonally arranged.
-1-2 and the geophone 5-1-3 are installed, and the rotation component of this layer is measured. Here, the layer boundary surface 3-1
Then, the presence or absence of twist and rotation of the entire structure 21 was measured,
If necessary, the same measurement is performed on the layer boundary surface 3 on the intermediate floor.

The displacement of the layer boundary surface 3 and the displacement of the reference surface 25 are measured by the geophone 5 (step 304). FIG. 7 is a diagram showing the displacement of the structure 21. The structure 21 of FIG. 7 shows a state before deformation, and the structure 21a shows a state after deformation. When the reference plane 25 is deformed to the position of the reference plane 25a by the fine movement 29, the displacement from the origin 33-1 to the origin 33-1a is the layer displacement 71-1 of the reference plane 25. Similarly, the origin 33
The displacement from -3 to the origin 33-3a is the layer displacement 71-3 of the layer boundary surface 3-1. The layer displacement 71 of the reference surface 25 and each layer boundary surface 3 is obtained, and the time change thereof is used as the time history of the layer displacement 71. The time history of the layer displacement 71 of the reference surface 25 and each layer boundary surface 3 may be calculated from the velocity time history of each origin 33.

Next, the time history of the interlayer displacement 73 and the rotation angle 8
The time history of 3 is calculated (step 305). Layer displacement 7
3 is a relative displacement of the layer boundary surface 3. Normally, it is assumed that the layer boundary surface 3 is not deformed, and it is considered that the deformation of the structure 21 occurs inside the layer 27 and can be described by the interlayer displacement 73. The interlayer displacement 73 is obtained as the difference between the vectors of the layer displacement 71 of the adjacent layer boundary surfaces 3. For example, when the vector of the time history of the layer displacement 73 is obtained from the difference between the time history vectors of the layer displacement 71-1 and the layer displacement 71-2 of FIG.

[0051]

[Equation 1]

It becomes The time history vector of the interlayer displacement 73 has three components along the x, y, and z coordinate axes. For example, the y component of the time history of the layer displacement 71-1 is y1 (t),
When the y component of the time history of the layer displacement 71-2 is y2 (t), the y component of the time history of the layer displacement 73 is Becomes Similarly, the time history of the interlayer displacement 73 between the layer boundary surfaces 3 is calculated.

FIG. 8 is a diagram showing the rotational displacement of the structure 21. As shown in FIG. 8, in addition to the horizontal component in the X-axis 41 direction, the horizontal component in the Y-axis 43 direction, and the vertical component in the Z-axis 45 direction, the displacements of the reference plane 25 and the layer boundary plane 3 are also in the same three directions. There is a rotating component around. The time history of the rotation angle 83 with respect to the inertial coordinate of the embedding coordinates in a certain layer boundary surface 3 is θ0 (t), and the time history of the layer displacement 71 of the origin 33 of the embedding coordinates in the same layer boundary surface 3 is d0 (t). , Where da (t) is the time history of the layer displacement 71 at an arbitrary point, and ra is the embedded coordinate value at an arbitrary point, the following relationship is established. However, the operation symbol x represents a vector product.

[0054]

[Equation 2]

Normally, the layer boundary surface 3 is a flat surface, and the X axis 41 and the Y axis 43 are embedded in this surface.
In the layer boundary surface 3-1 shown in FIG. 3, A (Xa, Ya, 0) which is the embedded coordinates of three points where the geophone 5-1-3, the geophone 5-1-1, and the geophone 5-1-2 are installed. ), B (Xb, Yb,
0), C (Xc, Yc, 0) and the relationship of Expression (2), the time history d0 (t) of the layer displacement 71 of the origin 33 of the embedded coordinates of the layer boundary surface 3-1 and the rotation angle 83 Time history θ0
The X, Y, and Z components of (t) are calculated. Each component can be represented as follows.

[0056]

[Equation 3]

[0057]

[Equation 4]

[0058]

[Equation 5]

[0059]

[Equation 6]

[0060]

[Equation 7]

[0061]

[Equation 8]

Next, the energy transfer rate (RMS ratio) 75
(Displacement), energy transfer rate (RMS ratio) 85 (rotation angle)
Is calculated (step 306). Generally, time history a
The root-mean-square value (sigma) a of (t) is represented by Formula (10).

[0063]

[Equation 9]

If the root mean square value of the x component of the interlayer displacement 73 between the i-th layer and the j-th layer due to the slight movement 29 is σdijx and the root mean square value of the x component of the layer displacement 71 of the reference surface 25 is σbx, then the i-th layer is obtained. Energy transfer rate (RMS ratio) 75 of the x component of the interlayer displacement 73 of the j-th layer to the layer displacement 71 of the reference surface 25
(Hdijx) is It is calculated by. The same applies to the y component.

FIG. 10 is a diagram showing the actual measurement / calculation results of the translational displacement in the diagnosis example. In the diagnostic example, the root mean square value of the interlayer displacement 73 of the translational displacement and the calculation result of the energy transfer rate (RMS ratio) 75 are the values shown in FIG. 10.

Further, the root mean square value of the rotation angle 83 around the x axis 41 of the i-th layer due to the slight movement 29 is σθix, and the root mean square value of the horizontal two components of the layer displacement 71 of the reference surface 25 is σbxy (where σbxy = ( .sigma.bx2 + .sigma.by2) 1/2), the reference plane 25 with the rotation angle 83 of the i-th layer about the x-axis 41 is rotated.
Energy transfer rate (RMS ratio) 85 for layer displacement 71 of
hθix is It is calculated by. The same applies to the y-axis and z-axis.

FIG. 11 is a diagram showing the actual measurement / calculation results of the rotational displacement in the diagnosis example. In the diagnostic example, the rotation angle of rotation displacement is 8
Calculation results of the root mean square value of 3 and the energy transfer rate (RMS ratio) 85 are values shown in FIG. 11.

In parallel with steps 303 to 306, the magnitude of the earthquake motion 31 is determined (step 30
1) The displacement of the reference plane 25 due to the action of the earthquake motion 31 is calculated (step 302). FIG. 9 is a diagram showing data of the seismic motion 31 which is a risk evaluation target in the diagnosis example. Here, the data of the ground motion 31 due to the Hyogoken Nanbu Earthquake near the structure 21 is temporarily used. In step 301,
As shown in FIG. 9, the earthquake motion 31 that is the target of the risk determination
Of maximum acceleration 51 and maximum velocity 5 near the structure 21
3. Determine the center period 55. In step 302, the maximum displacement 57 of the reference plane 25 is calculated from these data.

Next, estimated displacements (maximum values) 81, 87 due to the earthquake motion 31 are calculated (step 307).
That is, by using the maximum displacement 57 of the reference surface 25 due to the earthquake motion 31 to be evaluated shown in FIG. 9 and the microtremor observation result 63 and the microtremor observation result 84 shown in FIGS. (Value) 81 and estimated displacement (maximum value) 87 during an earthquake are calculated.

Generally, when the input of a linear system receiving a stationary irregular input is x (t) and the output is y (t), the mean square value σy of the output and the power spectral density function Sx (ω) of the input are given. Have the following relationships.

[0071]

[Equation 10]

H (ω) is called a transfer function. In the stationary process, there is the following relationship between the root mean square value (square root of the average power) and the expected value of the maximum value observed during a certain duration.

[0073]

[Equation 11]

Γ is a coefficient called a peak coefficient, which is a function of the duration S0 of the steady process y (t) and the distribution function. For a stationary Gaussian process, T0 is the central period of the stationary process.

[0075]

[Equation 12]

[0076]

[Equation 13]

In general, a sudden external force such as the seismic force 31 that destroys the structure 21 has a finite duration and an unsteady spectrum. Using equations (14) through (16) when calculating the power spectral density function,
There is a research result that the equivalent Gaussian process can be corresponded by obtaining the equivalent duration S0. That is, when calculating the power spectral density function, the calculation is performed as follows. However, X (ω) is the Fourier transform of x (t). That is,

[0078]

[Equation 14]

The transfer function is calculated as the quotient of the Fourier transforms of the input and output as follows. However, the Fourier transform of the output is also calculated from the time history y (t) of the output according to the formula (18).

In step 307, as a simple method,
The spectrum of the tremor 29 observed on the reference plane 25 near the ground 23 of the structure 21 shows that the ground 23 and the structure 21 are damaged by the large earthquake.
Is assumed to be similar to the spectrum that would be observed if it behaved linearly. Then, between the power spectral density function Sxg (ω) of the input xg (t) and the power spectral density function Sxb (ω) of the micromotion 29xb (t) due to the seismic motion 31 of the reference plane 25, Sxg (ω) = c2Sxb ( ω) ... (20) is established.

When this assumption is applied to the equation (13), the root mean square value σdg of the interlayer displacement due to the earthquake motion 31 and the root mean square value σdb of the interlayer displacement 73 due to the microtremor 29 are also similar. Therefore, the following relationship exists between the root mean square value σg of the layer displacement of the reference surface 25 and the root mean square value σdg of the layer displacement due to the earthquake motion 31.

Also, between the maximum values, there is a relation similar to the above equation via the peak factor. That is, the geophone 5
Of the energy transfer rate (RMS ratio) 75 (h) calculated from the time history of the layer displacement 73 due to the microtremor 29 and the time history of the layer displacement 71 of the reference surface 25, and the displacement of the reference surface 25 due to the earthquake motion 31. From the root mean square value σg,
It is possible to predict the root mean square value σdg and the maximum value γσdg of the interlayer displacement due to the earthquake motion 31.

From this, assuming that the maximum displacement 57 of the x component of the reference surface 25 due to the target earthquake motion 31 is bxmax, the maximum value dijxmax of the x component of the interlayer displacement of the i-th layer and the j-th layer caused by the earthquake motion 31 is , Using the energy transfer rate (RMS ratio) 75hdijx, It is calculated by. The same applies to the y component.

Similarly, assuming that the maximum displacement 57 of the x component of the reference surface 25 due to the target earthquake motion 31 is bxmax and the maximum displacement 57 of the y component is bymax, the x component of the rotation angle 89 of the i-th layer caused by the earthquake motion 31. Maximum value of θixm
ax is an energy transfer rate (RMS ratio) of 85hθix, Is calculated as follows (however, bmax = (bxmax2 + b
ymax2) 1/2). Similar calculations are performed for the y-axis and z-axis.

F67 used in the equation (23) and f (not shown) used in the equation (24) are coefficients considering the nonlinearity of the response. f67 is the yield point displacement d
Displacement calculated as if y and the structure behaved as a linear system without exhibiting nonlinearity, that is, hdijxbxm
It is expressed as follows using ax (equivalent elastic displacement 65 in FIG. 10). f = 1/2 (η + 1 / η), where η = hdijx
bxmax / dy, used only when η> 1)
(25) The same applies to the y component.

In the case of a building, the yield point displacement dy is usually defined as the interlayer deformation angle (value obtained by dividing the interlayer displacement by the floor height),
It is considered to be 1/200 to 1/100. F used in the equation (24) is also calculated in the same way as f67, but there is no concrete research result on the rotation angle at present, so f is set to 1 in this method.

In the above method, the system is linear and
The displacement components are independent of each other and the input is assumed to be stationary. With respect to the fine movements 29 of the ordinary structure 21, this assumption generally holds true. When subjected to a large external force such as the seismic force 31, which destroys the structures 21, most of the structures 21 exhibit remarkable nonlinearity. In addition, the external force itself has a finite duration and has remarkable non-stationarity. With respect to this problem, structural mechanics and structural design theory take the position of considering nonlinear and non-stationary effects by a coefficient f, based on the response of a linear system to a stationary process.

The method of the present invention follows this standpoint, and the commonly used coefficient f representing the above-mentioned nonlinear effect can be used as it is. However, in the first half of the explanation of step 307, when the method of the present invention is applied to a structure for which coupling of each component of vibration or calculation of nonlinearity is required by the structural design standard. It is necessary to consider performing the general method described above and performing three-dimensional analysis.

The calculation of equations (23) and (24) will be specifically described using a diagnostic example. For example, in FIG. 10, assuming that the maximum displacement 57 shown in FIG. 9 is 4 cm,
Multiplying the maximum displacement 57 by the energy transfer rate (RMS ratio) 75 gives an equivalent elastic displacement 65. Then, when the equivalent elastic displacement 65 is multiplied by f67, the elasto-plastic displacement 69 djmax is obtained, and when the elasto-plastic displacement 69 is further divided by the thickness of the layer 27, the interlayer deformation angle 82 is obtained. In addition, in FIG.
By multiplying the root mean square value of the two horizontal components (x component and y component) of the maximum displacement 57 and the energy transfer rate (RMS ratio) 85, the rotation angle 89θimax is obtained.

In parallel with steps 303 to 307, the layers, the displacement components, and the determination reference displacement amount which are important for determining the risk of the structure 21 are determined (step 308).
The reference deformation amount (interlayer displacement angle, rotation angle) is calculated (step 309). That is, the design conditions of the structure 21, the damage cases of the same kind of structure, the experimental data, etc. are collected, and step 3
Interlayer deformation angle 8 calculated in the procedure from 01 to step 307
The determination reference values for the data such as 2 and the rotation angle 89 are determined using those data.

Next, the degree of risk is judged (step 31).
0). That is, the estimated displacement during earthquake (maximum value) 81 and the estimated displacement during earthquake (maximum value) 87 shown in FIGS. 10 and 11 are compared with the determination reference value determined in step 309, and the structure 2
The degree of danger due to the earthquake motion 31 of 1 is determined. The inter-layer deformation angle 82 shown in FIG. 10 is a value obtained by dividing the elasto-plastic displacement 69 by the thickness of the layer 27, and is related to mechanical properties of structural elements (members) forming the layer 27, safety against fracture, etc. The research results of (1) are organized using the elasto-plastic displacement 69 or the interlayer deformation angle 82 as an index.

When the inter-story deformation angle 82 during an earthquake exceeds 1%, it is considered that there is a high risk of collapse of the layer 27. As shown in FIG. 10, in the diagnosis example, the inter-story deformation angle 82 estimated to be caused by the earthquake motion 31 exceeds 1% in all of the second to fourth floors in the X direction underlined and in the Y direction. It is a floor and is judged to be at risk of collapse by this diagnostic method. The interlayer deformation angle 82 in the X direction on the second floor is 0.99.
%, Which was less than 1%, and was judged to be dangerous.

As shown in FIG. 11, the estimated earthquake displacement (maximum value) 87 of the rotational displacement in the diagnosis example is about 1% around the Y-axis 43 and the Z-axis 45.
It is hard to say immediately that it is dangerous considering that the basic form of is a solid foundation. A rotation of 3% is predicted around the X axis 41. This value is large, and some plastic deformation (slope) is expected to remain, but it is hard to say that there is a risk of falling.

In order to confirm the consistency between this method and the existing method, FIG. 10 shows the values of the seismic index Is77 and the strength index CT / SD79 calculated according to the guidelines of the Japan Building Disaster Prevention Association. According to the Building Disaster Prevention Association guidelines, when the seismic resistance index Is77 is less than 0.6 and the strength index CT / SD79 is less than 0.3, it is determined that the layer is in danger of collapsing due to a large earthquake. There is a risk of collapse in both the judgment by the seismic index Is77 and the judgment by the inter-story deformation angle 82 of this method that there is a risk of collapse from the second floor to the fourth floor in the X direction and in the Y direction.
The earthquake resistance index Is77 of BF 0.61 is 0.61 which is the standard value.
Since it exceeds 0 very little, it is judged to be all the floors except the 4th floor when it is considered dangerous.

Regarding the Y direction of the fourth floor, it is judged that this method is dangerous and the earthquake resistance index Is77 determines that it is safe, but the judgments of both methods are consistent for all other floors and directions. The determination reference value of the earthquake resistance index Is77 increases as the energy of earthquake motion increases. If this is considered to be increased from the current 0.6 to 0.78, the determination results of both methods can be completely matched. This is consistent with the fact that the actual earthquake ground motion 31 illustrated here is said to be larger than the earthquake ground motions of the past disaster cases used at the time of creating the guidelines of the Japan Building Disaster Prevention Association.

The structure 21 of the diagnosis example has an actual earthquake motion 31.
The pillars on the 2nd and 3rd floors were severely damaged by the deformation in the X direction, and the judgment results are suitable for the disaster situation.
Regarding the 4th floor X direction and the Y direction from the BF to the 3rd floor, both methods were judged to be dangerous, but no serious structural damage was actually done, but the 2nd and 3rd floors were damaged in the X direction. Energy is absorbed and the upper floors (4th floor)
It seems that the damage in the Y direction was small. In this way, the fact that the behavior after a partial disaster is not taken into consideration is a problem common to all current design methods.

As described above, according to this embodiment, the following effects can be obtained. (1) From measurement to calculation and evaluation can be performed in a short time. The measurement takes about 2 hours for installing and measuring the machine, and the calculation is completed in a few minutes. When using the method of the Japan Building Disaster Prevention Association, a large amount of personnel is input, usually for about two weeks, to enter the structural drawing data, conduct and evaluate the concrete core removal test, and conduct the concrete test in a short period of time. Takes at least a couple of days.

(2) It is possible to carry out from measurement to calculation and evaluation at low cost. The cost of measurement and calculation is
Machine damage and labor costs, etc., but the conventional method costs several million yen per structure, but the method of the present invention costs several hundred thousand yen.

(3) It is possible to quantitatively evaluate the degree of danger with respect to various assumed earthquake ground motions 31. That is, the displacement of the reference plane 25 is calculated for a specific earthquake motion 31, and the method of the present invention is used for this. In the method of the Building Disaster Prevention Association, Is = 0.6 is used as the evaluation standard based on the analysis of the damage cases in the past great earthquakes, and the target earthquake motion 31 is not clear, so the level of earthquake risk is quantitatively evaluated. I couldn't. By using the method of the present invention, it is possible to quantitatively determine what kind of earthquake motion 31 is safe or dangerous.

(4) With respect to the layer 27 and the rotation angle 89 between layers, the degree of danger can be determined based on the measurement result. According to the method of the Japan Building Disaster Prevention Association, there is no direct regulation regarding twist. However, the architectural design standard requires that a twist on a newly built building be examined, and the method of the present invention can deal with this.
Regarding the influence of twist and rotation on structures, it is a field where research is actively progressing at academic societies and the like, and since twisting and rotation can be predicted by the method of the present invention, the knowledge obtained at academic societies can be used as a risk factor. The effect is that it can be reflected in the judgment.

(5) Indexes used in designing the seismic resistance of structures (inter-layer displacement, elasto-plastic displacement 69, rotation angle 8)
(9, etc.) can be directly obtained by measurement and calculation, so that the seismic risk judgment of a building can be directly associated with the design. The conventional methods are seismic index (Is), strength index (C
tSd) (above Japan Building Disaster Prevention Association) It is difficult to use the theoretical framework of seismic design, experimental data, etc., because the indexes for seismic risk judgment such as spectrum ratio and seismic risk index are calculated. On the other hand, the method of the present invention has an effect that it is possible to directly use the enormous accumulation of knowledge for the earthquake risk determination.

(6) Reference plane 25 for assumed earthquake motion 31
Since it is a method of calculating the interlayer displacement (elasto-plastic displacement 69) or the like from the displacement of No. 1, the earthquake motion 31 can be accurately evaluated. (7) Since the calculation is performed in consideration of the non-linearity of the structure 21, accurate evaluation can be performed. This is because the method of the present invention complies with the theoretical system used for design calculation.

(8) It can be used not only for evaluating the seismic risk of existing buildings but also for quality control of buildings under construction. Since this method directly measures the index used in the design calculation, it can be used to evaluate whether or not the building has the performance expected in the design during or after construction.

Next, another embodiment of the present invention will be described. In the above-described embodiment, the safety of the artificial structure when the external force such as an earthquake is applied is evaluated. Here, the evaluation target is expanded to include not only artificial objects but also natural objects, and the micromotion of the structure is observed to evaluate the safety and soundness. Safety refers to assessing the risk of structural destruction, and integrity refers to assessing the degree of achievement of the properties and qualities expected of a structure in design.

FIG. 12 shows a diagnostic system 1 according to another embodiment of the present invention. The structure 91 is not limited to an artificial structure, and includes cliffs, rocks, ground, and the like that are natural objects. A plurality of geophones 5 are installed inside or on the surface of the structure 91. The geophone 5 is connected to the measuring instrument 7 by a cable 11, and the measuring instrument 7 is connected to the computer 9 by a cable 13. The geophone 5 and the measuring instrument 7 have been described with reference to FIG. The connection between the geophone 5 and the measuring instrument 7 or the measuring instrument 7
The computer 9 and the computer 9 may be connected by wireless communication means.

The geophone 5 is installed inside or on any surface of the structure 91 or on the flat surface 3 in the structure like the geophones 5-7 to 5-9. The procedure for converting the data obtained by the geophone 5 is the same as that shown in FIG.

13 and 14 show examples of arrangement plans of observation points of the structure 91 (that is, installation points of the geophone 5). Geophone 5
The installation point of is a target point (or a target surface) of the structure 91 in consideration of the characteristics of the structure 91, environmental conditions, diagnostic items, and the like,
It is placed at the reference point (or reference plane).

FIG. 13 shows a base 93 having the same structure 91.
This is the case when you think you are on the ground (rock, rock, floor, etc.). If there is a part with changed properties inside the structure,
It is an arrangement plan of the geophone 5 for the purpose of diagnosing the position.
For example, if diagnosis is performed by fine movement in this embodiment, point A
It is found that the characteristics of the minute movement time history are different between point C and point B. That is, the vicinity of point B in FIG.
Turns out to be

Further, the position of the geophone 5 is changed from the point A to the point A1,
When the diagnosis is performed by moving from the point C to the point C1 and the point C2 to the point A2, the property change portion 95 of the structure can be diagnosed.

FIG. 14 shows a case in which a difference in boundary condition between the structure 91 and the base 93 is detected to make a diagnosis. Point A4, point B4, point C4 on the structure, and the base 93 in the vicinity of each point
An energy transfer rate (RMS ratio) is calculated between the points A3, B3, and C3 above to make a diagnosis.

Further, in the case of diagnosing a changed portion of the property inside the structure 91, as shown in FIGS. 4 to 6, the structure 91 is divided into layers and the reference plane and the attention plane are determined and the observation points ( Place a geophone 5).

Next, the procedure of diagnosis by fine movement will be described with reference to the flowchart of FIG. First, the structure 91 for evaluating and diagnosing the safety and soundness and the surrounding environment are preliminarily investigated (step 1001).

Next, the diagnostic items of the structure 91 are determined (step 1002). That is, it is determined whether the diagnostic item is a safety diagnosis against sudden external force, a soundness diagnosis, or both.

Next, the physical quantity of interest of the structure 91 and the points, planes, layers, etc. for which it is calculated are determined (step 1003). The physical quantity of interest is the amount of displacement or relative displacement of points or planes inside the structure, rotation angle between points, average compression strain, average shear strain, average bending strain, average torsion strain, and the like. For example, in the above-described embodiment, the physical quantities of interest are the “interlayer displacement” and the “rotation angle”. For structures such as buildings and bridges, reference is made to the layers and members considered in the design calculation, and the point of calculating the physical quantity and
Determine faces, layers, etc. Even for natural objects such as cliffs and ground, similar to the case of artificial structures, calculate the physical quantity of interest with reference to the dynamic model used for design calculation such as disaster prevention and reinforcement, and stability calculation. Determine points, faces, layers, etc.

When considering a sudden external force, the input reference plane and the observation time zone are determined (step 100).
4).

Next, step 1005 shows a processing procedure of software of the diagnostic system 1. 16
The function of inputting, calculating, displaying, and outputting in step 1005 is shown in detail, so that it will be described below with reference to FIGS. 15 and 16.

As an input item, an observation plan (that is, total number / position of observation points, observation time zone, observation frequency band, predominant vibration energy, reference point, reference surface, attention point, attention physical quantity, observation time history calculation item, etc.) It is determined (step 1006). This corresponds to the input 2006 of the observation point attribute in FIG.

Next, based on the above plan, the geophone 5 is installed on the structure 91 and the micromotion observation is carried out (step 10).
07). That is, the observation time history 20 of FIG.
03, at the same time, observation time and observation frequency band 2004,
The analysis time / analysis frequency band 2005 is determined. The data of the analysis time is taken out by setting the analysis start time and the analysis end time in the observation time zone. Data in the analysis frequency band is extracted by performing FFT conversion on the time history of analysis time and performing filter operation in the frequency domain.
By the inverse FFT transform, the time history data of the analysis time and the analysis frequency band from which the time history of interest is calculated are obtained. These calculations use the preliminary calculation routine 2013.

Next, the time history of interest is calculated (201 in FIG. 16).
1) and the power spectrum is calculated (step 10
08), and further the energy transfer rate (RMS ratio) is calculated (2012 in FIG. 16) (step 1009). The details will be described below. (That is, the calculation routine 2009 of FIG. 16 is entered.)

Assuming that the microtremor always has a very small amplitude and the structure responds linearly, the input (ie, observation time history) x (t) and the output (ie, time history of interest) y (t) There is a relationship between them, which is represented by the above equations (13) to (19). In the examples of Expressions (13) to (19), the input (that is, the observation time history) x (t) corresponds to the time history of the layer displacement 71 of the structure 21, and the output (that is, the attention time history) y (t). ) Corresponds to the time history of the interlayer displacement 73 and the time history of the rotation angle 83.

Therefore, from a certain observation time history, the transfer function H
(ω) is calculated using the above equations (13) to (19), and an output (ie, time history of interest) for an input (ie, observation time history) x (t) at a reference point or reference plane of an arbitrary waveform is obtained. ) Y
(t) can be calculated. However, this is the case where the input is limited to the reference plane, and when the structure 91 receives input from other planes, this effect also needs to be superimposed.

Using the above equations (13) to (19), the time history of interest and the power spectrum Sx (ω) are calculated (step 1008), and then the energy transfer rate (R
The MS ratio) is calculated (step 1009).

The energy transfer rate (RMS ratio) h is calculated by using the mean square value σx of the observation time history x (t) which is the input and the mean square value σy of the notice time history y (t) which is the output. Is defined as Note that σx and σy are defined by the above-mentioned equation (10). hxy = σy / σx (26)

The energy transfer rate (RMS ratio) h is the ratio of the root mean square value of the time history of interest to the root mean square value of the observation time history of the reference point or the reference surface by the micromotion observation. Since the root mean square value is related to the maximum value via the peak coefficient γ, it is approximately the ratio of the maximum values.

When performing a safety diagnosis for a sudden external force, the reference point displacement for a sudden external force is predicted (step 1010), and the reference point displacement (predicted value) 200 shown in FIG.
Input 2 as input data. The predicted maximum value of the physical quantity of interest is calculated from the energy transfer rate (RMS ratio) h calculated from the microtremor observation value and the reference point displacement (predicted value) 2002 (step 1012).

As described in the equations (20) to (22), the energy transfer rate (RMS ratio) h is a coefficient for calculating the response of the linear system. That is, from the energy transfer rate (RMS ratio) hxy calculated from the observation time history and the root mean square value σxg of the reference plane displacement predicted to occur due to an unexpected external force such as earthquake motion, the displacement of the point of interest or the layer caused by this external force , It is possible to predict the root-mean-square value σyg and the maximum value γσyg of time history such as distortion.
That is, there is the following relationship. σyg = hxyσxg (27)

In the above, the system is linear,
It is assumed that the displacement components are independent of each other and the input is stationary. However, when a structure is subjected to a sudden external force that causes the structure to break, most of the structure exhibits significant non-linearity. In addition, the sudden external force itself has a finite duration and has a remarkable nonlinearity. In this case, in structural mechanics and structural design theory, nonlinear and non-stationary effects are considered by coefficients based on the response of linear systems to stationary processes.

After the predicted maximum value of the physical quantity of interest for the unexpected external force is calculated, the safety of the structure 91 is diagnosed (step 1013). When the structure 91 is the structure 21, the calculated estimated displacement during earthquake (maximum value) 81, estimated displacement during earthquake of rotation angle (maximum value) 87, and the determination reference value (that is, the maximum allowable displacement 2008 shown in FIG. 16). ) And diagnose the safety.

When performing the soundness diagnosis of the structure 91, it is determined whether the structure of the structure 91 is in an expected state. That is, the energy transfer rate (RMS ratio) (expected value) expected for the structure 91 is predicted (step 101).
1), the soundness of the structure 91 is diagnosed by comparing with the energy transfer rate (RMS ratio) obtained by the microtremor observation (step 1014). That is, the soundness of the structure 91 is diagnosed by determining how much the structure 91 is expected from the property or quality expected according to the design. The energy transfer rate (RMS ratio) (expected value) 2007 expected for the structure 91 is the input data 2001 input by the diagnostician.
(FIG. 16).

Incidentally, when observing fine movement, conventionally, the Fourier amplitude spectrum is displayed on the measuring instrument 7 and visually observed to empirically judge the nature of the fine movement from its shape, and the frequency corresponding to the maximum amplitude is determined as the dominant frequency. Therefore, I made an analysis by using it as a diagnostic index. In the present invention, the diagnostician simultaneously observes the power spectrum during microtremor observation, and at the same time, displays it on the screen of the measuring instrument 7 or the computer 9 for visual observation. Further, the central frequency and the bandwidth index are calculated to quantify the spectrum shape, which is used as a criterion. That is, any observation time history x (t)
On the other hand, the central frequency ωc of the spectrum is expressed by the equation (28).
Then, the bandwidth index α can be expressed by Expression (29).

[0131]

[Equation 15]

[0132]

[Equation 16]

However, λi in equations (28) and (29)
Is the I-th moment of the power spectrum of the observation time history x (t) and is represented by the equation (30).

[0134]

[Equation 17]

Λ0 is the root mean square value of x (t). According to the random vibration theory, the central frequency ωc is an expected value of the average zero-cross frequency of the time history. Also, the bandwidth index α
Takes a value between 1 and zero, and α = 1 for a sine wave and α = 0 for white noise. By using these indexes, the frequency characteristics of the observation time history can be evaluated without depending on the subjectivity of the observer.

In particular, the frequency corresponding to the maximum value of the Fourier spectrum was conventionally used as the dominant frequency, but this value is one of the sample values that have little statistical significance and fluctuate depending on the observation. On the other hand, the central frequency ωc is an expected value of the dominant frequency.

Calculation of attention time history (step 1008)
Can be arbitrarily defined and calculated according to the characteristics of the structure 91, the displacement of interest, and the strain. For example, the structure 91
Is divided into horizontal layers such as buildings, bridges, and ground,
A specific method of calculating the time history of interest will be described by taking as an example a case where diagnosis is performed by paying attention to strains such as shearing, twisting, and bending in this layer.

The structure 91 is divided into layers on a horizontal plane, and three observation points (the geophone 5) are installed on the boundary surface. Assuming that the fine movement displacement is minute, the rotation angle time history θ0 (t) with respect to the inertial coordinate system of the coordinate system in which a certain layer boundary surface is embedded
, The displacement time history d0 (t) of the origin, the displacement time history da (t) of an arbitrary point, and the embedded coordinate value ra of an arbitrary point satisfy the above-described equation (3).

Also, the time history of the origin of the embedded coordinates of each of the three points, and the X, Y of the time history of the fine movement rotational displacement of interest,
The Z component is represented by the above equations (4) to (9). These calculation formulas are applied to the observation time history of the observation point to calculate the attention time history of the plane where the observation point (the geophone 5) is installed.

Further, the minute movement layer displacement time history, the fine movement layer rotation angle time history, and the fine movement strain time history in the layer as attention time history are calculated and diagnosed. The fine movement layer displacement time history is a relative displacement time history between the layer boundary surfaces i and j, and is represented by the above-mentioned equation (1). (In equation (1), i = 1, j =
The case of 2 is shown. )

When it is not necessary to pay attention to the rotational motion of the layer boundary surface like the middle floor of a flat building, the layer boundary surface is set to 1
Each of the geophones 5 is installed, and the observation time history of this displacement is used as the displacement of the representative point. For example, for the y component, equation (3
1) is established.

Yi (t) and yj (t) are y components of the fine movement displacement time history of the origin or representative point of the embedded coordinates of the layer boundaries i and j of interest in the structure.

The shear strain or axial strain in the layer can be calculated by dividing the interlayer displacement by the layer thickness ly. Also,
The fine motion torsion rate time history ψijz (t) is expressed by Expression (32) using the difference in the time history of the fine motion rotation angle around the Z axis and the layer thickness ly.

The fine movement curvature time history is expressed by the equation (3) using the difference between the fine movement rotation angle time history about the X axis and the Y axis and the layer thickness ly.
3) and the formula (34).

As described above, the observed time history x
The time history of interest is calculated as the output y (t) for (t), the energy transfer rate (RMS ratio) h is further calculated, and this is used as an index to diagnose the soundness of the structure 91 and to protect against unexpected external forces. Make a diagnosis.

Here, the description of the functions shown in FIG. 16 will be supplemented. As shown in FIG. 16, the software function of this embodiment is composed of an input data 2001 function, a calculation routine 2009 function, a display routine 2014 function, and an output / transfer routine 2017 function.

In the input data 2001, the observer inputs the reference point displacement (predicted value) 2002, the observation point attribute 2006 including the installation information of the geophone 5, and the energy transfer rate (R
An MS ratio) (expected value) 2007 and an allowable maximum displacement (design value) 2008 for safety judgment. Observation time history 200
3 is data observed by the geophone 5. Observation time
Observation frequency band 2004, analysis time / analysis frequency band 2
005 is data set by the observer from the observation time history 2003.

The calculation routine 2009 part comprises a main calculation routine 2010 part and a preliminary calculation routine 2013 part. This calculation routine 2010 calculates the time history of interest 20
11 (step 1008 of FIG. 15) and calculation of energy transfer rate (RMS ratio) 2012 (step 100 of FIG. 15)
9). The preliminary calculation routine 2013 is a fast Fourier transform (FFT) or inverse transform of numerical information, a filter operation,
This is a calculation function such as power spectrum calculation and zero point correction. When calculating this calculation routine 2010, the necessary preliminary calculation routine 2013 is combined and calculated to speed up the calculation.

The display routine 2014 monitors whether the observer or the diagnostician observes the observation time history at the same time as the microtremor observation and confirms whether the observation is normally performed. It is also used to confirm whether the observation time history has the measured attributes, confirm the numerical information necessary for diagnosis, and change the observation plan such as the number and position of observation points as necessary.

The display items display input data, observation time history, etc. (2015 copy), and display time history, power spectrum, etc. as calculation results (2016 copy).

The output / transfer routine 2017 outputs the observation result and the calculation result to a hard storage medium or an output medium, or transfers them to the Internet or the like. For example, a diagnostician at a remote place can make a diagnosis simultaneously with the observation.

As described above, according to this embodiment, the following effects can be obtained. (1) The soundness and safety of a structure can be quickly and inexpensively diagnosed without directly applying an external force to the structure.

(2) The energy transfer rate (RMS), which is the ratio of the root mean square (RMS), to the relationship between the time histories used for diagnosis.
By using the ratio, which is easy to calculate, objective, and meaningful in terms of physical and random vibration theory, it is possible to directly use the information obtained by microtremor observation for diagnosis.

(3) Directly diagnosing the information obtained by the microtremor observation by directly calculating the time histories of the physical quantities required for the judgment of the safety and soundness of the structure from the time histories obtained by the microtremor observation. It can be used for.

(4) By selecting the amount used in ordinary structural mechanics such as displacement, interlayer displacement, shear strain, bending strain, stability calculation, and structural calculation as the time history of interest, the progress of this diagnosis The results can be easily weighed against the results of other methods. Therefore, the reliability of the diagnosis result can be improved, and the diagnosis can be performed in combination with other methods.

(5) Monitor the observation status during microtremor observation,
By performing diagnostic calculation in parallel with observation, soundness and safety can be quickly diagnosed.

(6) During microtremor observation, change the observation plan such as observation points and observation time zones based on the display of observation conditions and diagnostic results, and obtain optimum results under the constraints of the site. Diagnosis can be performed.

(7) A diagnostician at a remote place can participate in the diagnosis by transferring intermediate data and results of microtremor observation and diagnosis through the Internet or the like. Therefore,
The reliability of the diagnosis result can be improved, and the diagnosis plan such as the arrangement of the observation points can be optimized quickly.

(8) An amount directly related to the diagnosis of the safety / health of a structure is calculated as a noticed time history, and the relationship between the noticed time history and the vibration of the reference plane is expressed by an energy transfer rate (RMS ratio). , Made it possible to directly use the information obtained by microtremor observation for diagnosis.

(9) The frequency characteristics of the observation time history are calculated and expressed by the indices of the central frequency and the bandwidth index, which enables an objective judgment.

The present invention is not limited to the examples shown in the embodiments, but can be applied to other fields.

[0162]

As described above in detail, according to the present invention, the energy transfer rate (RM
By using the S ratio) as an index, it is possible to provide a diagnostic method and a diagnostic system that can perform a simple, quick, and inexpensive diagnostic of the safety and soundness of a structure that is a natural object or an artificial object.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a diagnostic system 1 according to a first embodiment.

FIG. 2 is a flowchart of conversion of data collected by the diagnostic system 1.

FIG. 3 is a flowchart of a diagnostic method.

FIG. 4 is a schematic explanatory diagram of a vibration and a structure 21 to be evaluated.

FIG. 5 is a diagram showing an installation position of a geophone 5 in a diagnosis example.

FIG. 6 is a diagram showing an installation position of a geophone 5 in a diagnosis example.

FIG. 7 is a diagram showing the displacement of the structure 21.

FIG. 8 is a diagram showing the displacement of the structure 21.

[Fig. 9] Earthquake motion 31 to be evaluated for risk in the diagnosis example
Figure showing the data of

FIG. 10 is a diagram showing measurement / calculation results of translational displacement in a diagnosis example.

FIG. 11 is a diagram showing the measurement / calculation results of the rotational displacement in the diagnosis example.

FIG. 12 is a configuration diagram of a diagnostic system 1 according to a second embodiment.

FIG. 13: Observation point arrangement example 1

[Fig. 14] Observation point arrangement example 2

FIG. 15 is a flowchart showing the processing of the diagnostic system 1.

FIG. 16 is a flowchart showing the processing of the computer 9 of the diagnostic system 1.

[Explanation of symbols]

1 ... Diagnostic system 3 ... Layer boundary surface 5 ………… Geophone 7 ... Measuring instrument 9 ... Computer 21 ……… Structure 23 ………… Ground surface 25 ……… Reference plane 29 ………… Slight movement 31 ……… Seismic motion 57 ... maximum displacement 73 ………… Layer displacement 75 ………… Energy transfer rate (RMS ratio) 81 ………… Estimated displacement during earthquake (maximum value) 83 ... Rotation angle 85: Energy transfer rate (RMS ratio) 87 ………… Estimated displacement during earthquake (maximum value) 91 ......... Structure 93 ……… Base 95 ..... Changes in the properties of the structure 97 ………… Point A 99 ………… B point 101 ......... C point 103 ... Structure surface

─────────────────────────────────────────────────── ─── Continuation of the front page (56) Reference JP-A-5-281082 (JP, A) JP-A-7-146373 (JP, A) JP-A-8-5522 (JP, A) JP-A-8- 128030 (JP, A) JP 9-15106 (JP, A) JP 9-105665 (JP, A) JP 10-102357 (JP, A) JP 10-267646 (JP, A) JP 2000-208641 (JP, A) JP 2001-215167 (JP, A) JP 2002-148244 (JP, A) JP-B-7-1223 (JP, B2) JP-B 7-6884 (JP, B2) (58) Fields investigated (Int.Cl. ⁷ , DB name) G01M 7/02

Claims (41)

(57) [Claims] 1. A microtremor time history obtained from a microtremor observation value of a structure is observed at a reference point and a plurality of observation points to predict the behavior of the structure when a sudden external force acts on the structure. In the method of diagnosing a structure, an observation time history is obtained from the microtremor time history observed at the reference point and a plurality of observation points at the same time, and an attention time history is calculated in a time domain from the observation time history. Calculate the ratio of the root mean square value of the time history to the root mean square value of the observation time history of the reference point, and calculate the ratio and the square of the observation time history of the reference point predicted when the sudden external force acts. A method of diagnosing a structure, which comprises multiplying an average value to calculate a prediction result. 2. The power spectrum of the observation time history or the attention time history suddenly exerts an external force on the structure,
The method for diagnosing a structure according to claim 1, wherein the observation time zone is selected so as to be substantially similar to the power spectrum of the time history occurring in the structure when it is considered that the structure behaves elastically. 3. A step of comparing the judgment reference value determined from the design conditions of the structure and a predicted maximum value of the time history of interest to judge the risk of the structure due to the sudden external force. The diagnostic method for a structure according to claim 1 or 2, further comprising: 4. A plurality of geophones, a communication unit, a measuring instrument, and a computer for diagnosis, wherein the geophones are arranged on a reference plane and a boundary surface of the structure, A plurality of boundary surfaces are set.
Method for diagnosing structures. 5. The method for diagnosing a structure according to claim 4, wherein a plurality of geophones are arranged on at least one surface of the plurality of boundary surfaces. 6. The method for diagnosing a structure according to claim 4, wherein the geophone and the measuring instrument are contained in one case so that the vibration of the instrument is not detected by the geophone. 7. The method for diagnosing a structure according to claim 1, wherein the microtremor observation value is at least one of displacement, velocity and acceleration of the observation point or plane. 8. The method for diagnosing an object according to claim 1, wherein the time history of interest is at least one time history of displacement of the observation point or plane, displacement between layers, rotation angle, and strain. 9. A microtremor time history obtained from microtremor observation values of a structure is observed at a reference point and a plurality of observation points to predict behavior of the structure when a sudden external force acts on the structure. The structure diagnostic system includes a plurality of geophones installed at an observation point or a plane of the structure, a communication unit, a measuring instrument, and a computer, wherein the geophones are micromotions added to the structure. Is sent to the measuring device via communication means, the measuring device sends the microtremor observation value to the computer via communication means, the computer obtains an observation time history from the micromotion time history, Calculate the time history of interest in the time domain from the observation time history,
Next, the ratio of the mean square of the time history of interest and the mean square of the observation time history of the reference point is calculated, and this ratio and the observation time of the reference point predicted when the sudden external force acts A system for diagnosing a structure, wherein a prediction result is calculated by multiplying a root mean square value, and simultaneously observed values are used as microtremor observation values at the reference point and a plurality of observation points. 10. The power spectrum of the observation time history or the attention time history shows the time history generated in the structure when it is considered that an external force suddenly acts on the structure and the structure behaves elastically. The structure diagnosis system according to claim 9, wherein the observation time zone is selected so as to be substantially similar to the power spectrum. 11. A means for judging the risk of the structure due to the sudden external force by comparing a judgment reference value determined from design conditions of the structure and a predicted maximum value of the time history of interest. The diagnostic system for a structure according to claim 9 or 10, further comprising: 12. The system for diagnosing a structure according to claim 9, wherein the microtremor observation value is at least one of displacement, velocity and acceleration of the observation point or plane. 13. The diagnostic system for an object according to claim 9, wherein the time history of interest is at least one time history of displacement of the observation point or plane, displacement between layers, rotation angle, and strain. 14. The structure diagnostic system according to claim 9, wherein the communication unit is wired or wireless. 15. The structure diagnostic system according to claim 9, wherein the communication unit is a cable. 16. The diagnostic system for a structure according to claim 9, wherein the communication means is a radio wave or a medium such as a flexible disk or a memory card. 17. The diagnostic system for a structure according to claim 9, further comprising a display device for displaying a diagnostic result. 18. The structure diagnostic system according to claim 9, wherein the geophone is disposed on a reference plane and a layer boundary surface of the structure. 19. The structure diagnosis system according to claim 18, wherein a plurality of boundary surfaces are set. 20. The structure diagnostic system according to claim 19, wherein a plurality of geophones are arranged on at least one of the plurality of boundary surfaces. 21. The structure diagnostic system according to claim 20, wherein the geophone and the measuring instrument are housed in one case so that vibration of the instrument is not detected by the geophone. 22. A history of microtremors obtained from microtremor observation values of a structure is observed at a reference point and a plurality of observation points to predict the behavior of the structure when a sudden external force acts on the structure. In a computer used for the method of diagnosing a structure, an observation time history is obtained from the minute movement time history, an attention time history is calculated from the observation time history in a time domain, and then a root mean square value of the attention time history and the reference point are obtained. Of the observation time history root mean square value is calculated, and the prediction result is calculated by multiplying this ratio by the root mean square value of the observation time history of the reference point predicted when the sudden external force acts. A computer characterized by using simultaneously observed microtremor observation values at the reference point and a plurality of observation points. 23. The power spectrum of the observation time history or the time history of interest indicates the time history generated in the structure when it is considered that the structure behaves elastically due to an unexpected external force acting on the structure. 23. The computer according to claim 22, wherein the observation time zone is selected so as to be substantially similar to the power spectrum. 24. A means for judging the risk of the structure due to the sudden external force by comparing a judgment reference value determined from design conditions of the structure and a predicted maximum value of the time history of interest. The computer according to claim 22 or 23, further comprising: 25. The computer according to claim 22, wherein the microtremor observation value is at least one of displacement, velocity and acceleration of the observation point or plane. 26. The computer according to claim 22, wherein the time history of interest is at least one time history of displacement of the observation point or plane, displacement between layers, rotation angle, and strain. 27. A program causing a computer to function as the computer according to any one of claims 22 to 26. 28. A recording medium recording the program according to claim 27. 29. A microtremor history obtained from microtremor observation values of a structure is observed at a reference point and a plurality of observation points to predict the behavior of the structure when a sudden external force acts on the structure. In the structure diagnostic device, a plurality of geophones installed at an observation point or a plane of the structure, a communication unit, a measuring instrument, and a computer are provided. And sends the data to the measuring instrument via the communication means, the measuring instrument sends the microtremor observation value to the computer via communication means, and the computer observes from the microtremor time history. The time history is obtained, and the time history of interest is calculated from the observation time history in the time domain, and then the ratio of the mean square of the time history of interest and the mean square of the observation time history of the reference point is calculated. Predicted when the sudden external force is applied A method for calculating a prediction result by multiplying the root mean square value of the observation time history of the reference point, characterized in that it uses those observed simultaneously as microtremor observation values at the reference point and a plurality of observation points. Diagnostic device for structures. 30. The power spectrum of the observation time history or the time history of interest indicates the time history generated in the structure when it is considered that the structure behaves elastically due to an unexpected external force acting on the structure. 30. The structure diagnostic apparatus according to claim 29, wherein the observation time zone is selected so as to be substantially similar to the power spectrum. 31. A means for judging the risk of the structure due to the sudden external force by comparing a judgment reference value determined from design conditions of the structure and a predicted maximum value of the time history of interest. 31. The structure diagnostic apparatus according to claim 29 or 30, further comprising: 32. The structure diagnostic apparatus according to claim 29, wherein the communication unit is wired or wireless. 33. The structure diagnostic apparatus according to claim 29, wherein the communication unit is a cable. 34. The diagnostic device for a structure according to claim 29, wherein the communication means is a radio wave or a medium such as a flexible disk or a memory card. 35. The diagnostic device for a structure according to claim 29, further comprising a display device for displaying a diagnostic result. 36. The structure diagnostic apparatus according to claim 29, wherein the geophone is disposed on a reference plane and a layer boundary surface of the structure. 37. The structure diagnosis apparatus according to claim 36, wherein a plurality of boundary surfaces are set. 38. The structure diagnostic apparatus according to claim 37, wherein a plurality of geophones are arranged on at least one of the plurality of boundary surfaces. 39. The structure diagnostic apparatus according to claim 29, wherein the geophone and the measuring instrument are housed in one case so that the vibration of the instrument is not detected by the geophone. . 40. The diagnostic apparatus for a structure according to claim 29, wherein the microtremor observation value is at least one of displacement, velocity and acceleration of the observation point or plane. 41. The object diagnosis apparatus according to claim 29, wherein the time history of interest is at least one time history of displacement of the observation point or plane, displacement between layers, rotation angle, and strain.