Structure diagnostic evaluation method based on microtremor of structure

Abstract

To provide a microtremor-based structure diagnostic evaluation method that is different from a conventional method of performing a diagnostic evaluation of safe and soundness of a structure as well as safety thereof by directly applying external force and the like to an object, and can perform a diagnostic evaluation of earthquake proof of the structure, as well as safe and soundness thereof, and an effect of a countermeasure work and reinforcement work thereof at low costs and quickly.SOLUTION: A method for evaluating a performance of a structure due to a microtremor observation is configured to: observe a microtremor observation history at a plurality of observation points within the structure; calculate an estimation value of an index to be used in an earthquake proof design of the structure, using a root mean square (RMS) of these time histories; and perform an evaluation of an earthquake proof performance on the basis of the observation of the structure, using a ratio of the value to be used at a time of designing to the value of the index.SELECTED DRAWING: Figure 4

Description

[Technical field]

[0001] The present invention is a method for evaluating the earthquake resistance and soundness of a structure and the effectiveness of countermeasures and reinforcement works based on the microtremors of the structure. This is a technology relating to a method for diagnosing and evaluating the effectiveness of a structure. [Background technology]

[0002] For various things around us, from human bodies, machines, and buildings to cliffs, ground, and trees. Diagnosing and evaluating the performance of many devices is essential for living a safe and comfortable life. The technology is already in practical use. Diagnostic assessment of the health of animals is difficult due to the following reasons: Each one has a different shape and material. Destructive testing is not possible. The scale of the data exceeds that of a human. It is difficult to move. It cannot be completely described by documents or data. Structures are supported by the ground, and the properties of the ground are more complex than those of man-made structures that can be seen on the ground. There is a high degree of uncertainty regarding the timing, scale, and vibration characteristics of sudden external forces such as earthquakes. stomach.

[0003] In addition, the method of calculating the structural seismic index (Is value) for evaluating the earthquake resistance of existing buildings has changed from the conventional method. The project is carried out by experts who input information from drawings and other sources into a computer program. The complex calculations required a lot of time and money. Furthermore, the calculation method was not unique. Because there were inputs based on branching and judgment, it was considered that subjective elements were likely to be included. In other words, the above conventional method requires a lot of cost. It was labor-intensive and time-consuming.

[0004] The diagnostic evaluation methods that have been put into practical use so far for the entire structure include: a) using drawings and calculations; a) checking the consistency with the document, b) redoing the structural calculations, and c) calculating using a different method. d) Those that measure the shaking by applying vibrations using a vibrator, etc., e) Check sheets f) based on microtremor observations. a) or b), and seismic assessment falls under c). However, the plans listed in a) to c) The method using calculations involves extracting numerical values ​​from drawings, etc., and therefore is not suitable for actual structures and It is assumed that the support conditions are as they are. Even if detailed calculations could be performed to make a 100% accurate judgment, the condition of the foundation and the surrounding ground The calculation results are largely dependent on the conditions. Also, using the vibration generator listed in d) The energy of the vibration generator is too small compared to the potential energy of the structure and the surrounding ground. As with structural calculations, it cannot be said that the judgment is highly accurate.

[0005] Microtremors provide information that is much more comprehensive, detailed, and voluminous than the information on which the above methods rely. It contains information about the structure and the surrounding ground. Microtremors have an amplitude of only a few microns. Although it is small, the huge mass of the structure and the surrounding ground is constantly vibrating, so it generates a large amount of energy. Spatially, vibrations occur at all points in the structure and the surrounding ground, and the amount of information is The amount of information is incomparable to that of design documents and vibration generators. In order to evaluate the effect of earthquakes, it is important to be able to measure actual vibrations with the input source being the ground, just like earthquakes. .

[0006] Conventionally, there have been methods for diagnosing structures using microtremors, such as the technology disclosed in Patent Document 1. Several attempts have been made to achieve this. [Prior art documents] [Patent documents]

[0007] [Patent Document 1] Patent No. 3876247 Summary of the Invention [Problem to be solved by the invention]

[0008] However, in the conventional technology, the period that is considered to be dominant is visually determined from the Fourier spectrum. This method involves determining the magnitude of the fluctuations and discussing the changes in the fluctuations. Therefore, the results of the diagnosis were insufficient in terms of both accuracy and content, and the structure In addition, the prior art, including Patent Document 1, The calculated index was not used in the current design standards or seismic assessment standards. In addition, the current standards were not designed to be applicable to assessment and diagnosis within the framework of the standards. The indicators do not directly evaluate the continued use of structures. However, the seismic resistance of existing structures is In this specification, the design standards and seismic assessment standards are collectively referred to as the current standards. The standards are simply referred to as diagnostic standards, and the seismic design standards are simply referred to as design standards.

[0009] In addition, the distribution coefficient of story shear force in the height direction, horizontal bearing capacity, and There is no method to actually measure the product of cumulative strength index and shape index used in seismic diagnosis. The current standards do not specify the expected earthquake motion, and the current calculation method is There was also the problem of inputs being based on branching and judgment rather than intentional.

[0010] In view of the above problems found in the prior art including the above-mentioned Patent Document 1, the present invention provides a method for preventing micro-tremors The information is used in the diagnosis and seismic retrofit design of existing structures, and is used as the cumulative strength index and structural seismic index. The expected value of the standard and the expected value of the distribution coefficient of the story shear force in the height direction used in the current design of new buildings and estimation of the above indicators and damage level in relation to the damage level to directly evaluate the continued use of the structure. By directly obtaining the measured values ​​of microtremors, information on the actual structure and surrounding ground system can be obtained. The purpose of this study is to provide a new method for extracting and using the extracted information in the design and diagnostic evaluation of structures. The method of the present invention is called Micro Tremor Diagnosis (MTD). It is called. [Means for solving the problem]

[0011] The present invention has been made to solve the above problems, and its structural features include a constant micromotion A method for evaluating the performance of a structure by observation, comprising: simultaneously measuring the performance of the structure at a plurality of observation points; The microtremor time history was observed and the root mean square (RMS) of the time history was used to estimate the The estimated value of the index used in the seismic design of the above structure is calculated, and the above-mentioned Using the ratio to the value of the index, an evaluation of the seismic performance of the structure based on the observation is performed. It says:

[0012] In addition, the continuously measured microtremor time history is divided, a plurality of partial time histories are extracted, and each Calculate the expected value of the index for a partial time history, and use the sample average as the estimated value of the index. In this case, the duration of the partial time history is set to 1 to 2 minutes. is desirable.

[0013] In the present invention, the observation is performed after the construction of a structure, before and after repair work, and during periodic diagnosis. By comparing the estimated values ​​at each observation time, the seismic performance of the structure and the ground At least one of the following: the risk of collapse during an earthquake and the change in continuity of use over time and the change before and after the repair work The present invention may be used to diagnose and evaluate either of the above.

[0014] In the present invention, the index is the distribution coefficient of the story shear force in the height direction specified in the current standard, The horizontal bearing capacity may be as specified in the current standards.

[0015] In the present invention, the index is the base shear coefficient defined in the current standard or the It may also be a specified acceleration response magnification.

[0016] Furthermore, in the present invention, the index is a cumulative strength index and a shape index defined in the current standard. Alternatively, the degree of damage or the degree of risk of falling, which are newly defined in the present invention, may be used. Effect of the Invention

[0017] According to the present invention, the cumulative strength index, which is currently used for diagnosis and seismic retrofit design of existing structures, The expected value of the structural seismic index and the distribution coefficient of the story shear force in the height direction used in the current design of new buildings The expected number of damages and the newly defined damage estimates to directly assess the continued use of structures By directly obtaining each of these from microtremor measurements, vertical arrays were installed on each part of the structure. Through observation, it is possible to measure the vibration characteristics, strength, and degree of damage of each floor part (zone). As a result, earthquake resistance, soundness, or retrofitting can be carried out in a much more detailed, rapid, and inexpensive manner than with conventional methods. This makes it possible to evaluate the effectiveness of the design.

[0018] In other words, according to the present invention, by using the above indexes, after new construction, after renovation work, and after regular maintenance, At the time of clinical diagnosis, the diagnostic evaluation would be much cheaper and faster than current diagnostic evaluation or testing methods. This allows for rational seismic reinforcement design and seismic construction of new structures. This means that it will be possible to carry out calculations. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is an explanatory diagram showing an example of the configuration of a diagnostic system to which the method of the present invention is applied; [Diagram 2] FIG. 1 is a flowchart showing a basic processing procedure performed between a micromotion sensor and an analyzer. [Diagram 3] FIG. 2 is an explanatory diagram showing factors necessary for calculating the structural seismic index, horizontal bearing capacity and damage level in the method of the present invention. [Figure 4] FIG. 2 is a flowchart showing the overall processing procedure of the method of the present invention. [Diagram 5] FIG. 2 is an explanatory diagram showing the processing contents performed in the analyzer by routine. [Figure 6] Schematic diagrams showing the action and seismic force of an actual earthquake, where (a) shows the actual action, (b) shows the spring-mass system, and (c) shows the seismic force. [Figure 7] A model (single mass system) diagram that combines the multiple masses and springs depicted in Figure 6(b) with black dots and lines. [Figure 8] A graph showing the bilinear relationship between cumulative strength index and story drift angle. [Figure 9] A graph showing the relationship between friction-type interlayer shear force and support part acceleration. [Figure 10] A graph showing the relationship between friction-type interlayer shear force and interlayer velocity. [Figure 11] A graph showing the relationship between friction-type inter-story shear force and inter-story displacement. [Figure 12] An example of the layout of four types of microtremor sensors on the first floor of a four-story hospital. [Figure 13] The layout of four types of microtremor sensors on the second floor of the four-story hospital is shown as an example. [Figure 14] The layout of four types of microtremor sensors on the third floor of the same four-story hospital is shown as an example. [Figure 15] The layout of four types of microtremor sensors on the fourth floor of the same four-story hospital is shown as an example. [Figure 16] Y Hospital 1st floor column wall and 2nd floor floor beam plan. [Figure 17] Y Hospital 2nd floor column wall and 3rd floor floor beam plan. [Figure 18] Y Hospital X direction single frame diagram. [Figure 19] Y Hospital X direction 2-way frame diagram. [Figure 20] Y Hospital X direction 4-way frame diagram. [Figure 21] Y Hospital Y direction A-through frame diagram. [Figure 22] Y Hospital Y direction B axis frame diagram. [Figure 23] FIG. 11 is a panoramic view of the building according to the second embodiment. [Figure 24] The installation status of the A2 measuring instrument on the first floor in Figure 23 corresponds to Figure 25. [Diagram 25] FIG. 25 is an explanatory diagram showing the arrangement of measuring instruments and the reinforcement positions corresponding to FIG. 24 . [Figure 26] Microtremor displacement trajectories for each floor. [Figure 27] Animation of vibrations measured on the roof of an 11-story SRC building before reinforcement. [Figure 28] Animation of vibrations on the roof of an 11-story SRC building measured after reinforcement. Displacement data (XYZ three components) from microtremor sensors installed in three locations on the roof surface after reinforcement was input into structural analysis result visualization software, and a moment of visualization (animation) was shown. [Figure 29] A schematic diagram showing the relative positions of a block wall, foundation, ground, and microtremor meter. [Diagram 30] An explanatory diagram showing the overall view of a block wall in different situations (a) to (c). [Diagram 31] Diagram of micromotion gauge placement on block wall and reference point. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] The ground around the structure is constantly vibrating. The source of the vibration energy is the tides. , traffic vibrations, etc. The amplitude is a few microns [10 = -6 m]. Microtremors observed in the vicinity of the building (hereinafter simply referred to as "microtremors") are microtremors in the surrounding ground that move from the foundation to the This is the result of the signal entering the structure from the ground and being amplified or attenuated as it propagates through the structure.

[0021] Microtremors are observed by microtremor meters (accelerometers) installed inside the structure. is the absolute acceleration at a specific point, and is usually divided into three orthogonal components, the vertical component and the horizontal component, Since the amplitudes are small and the duration is short, the structure is a steady-state linear system. The tremors are a stationary stochastic process. ocess).

[0022] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an explanatory diagram showing an example of the configuration of a diagnostic system. According to the diagram, the entire diagnostic system includes: A microtremor 1 disposed at layer boundaries 10a, 10b, and 10c of each layer of a structure 10; Based on the data recorded in 1, various vibration characteristic indexes and various seismic resistance indexes used in the current standards An analyzer (e.g., a personal computer) 2 that calculates the sex evaluation index and the new evaluation index; It is composed of:

[0023] Among these, the micromotion meter (e.g., Hakusan Kogyo's micromotion meter JU410) 1 is an acceleration sensor The analyzer 2 is equipped with micromotion diagnostic software. The data recorded by the micromotion sensor 1 is received via USB, LAN, or the Internet. The calculations of the method of the present invention described in detail below were performed, and various vibration characteristic indexes and the current standards were obtained. The analyzer 2 calculates various seismic resistance evaluation indices that are already used and new evaluation indices. For example, the microtremor displacement data acquired by the microtremor gauges 1 installed at three locations is loaded onto the analyzer 2. The motion of the surface is then sent to the visualization software, which animates it in 3D and analyzes it using the The vibration of the structure 10 is displayed on a display means (display) not shown. Or, the vibration mode is displayed and visualized so that it can be clearly seen at a glance.

[0024] The outline of the method of the present invention will be described below with reference to Figs. 2 to 5. Fig. 2 shows a micromotion meter 1 and an analyzer. FIG. 2 is a flow chart showing the basic processing procedure performed between the Dynamic gauge 1 measures and records microtremors (acceleration time history of observation points and reference points on layer boundaries). The analyzer 2 filters the received measurement record data in the frequency domain and then The acceleration time history of the frequency band near the natural frequency of the structure is obtained. After that, the video is divided into parts of about 2 minutes in the time domain, and the time history of interest is recorded for each part. , energy transfer rate, and various indices are calculated. After the calculation, the vibration characteristic index for each part is Calculate the average value and standard deviation of the seismic resistance performance index and the seismic absorption performance index, and The process of treating the value as an estimate is carried out.

[0025] In addition, according to FIG. 3, the magnitude of the earthquake motion assumed in the method of the present invention is the maximum acceleration, the maximum velocity, and the maximum The magnitude of the earthquake is expressed in terms of the magnitude of the earthquake, maximum displacement, and duration of the strong earthquake. The performance of the target layer of the target structure is determined based on the required It is expressed in terms of horizontal strength, toughness index, age index, and limit number of cycles. After the installation of the meter is completed, the microtremor measurement and the analysis are performed using the microtremor meter 1 according to the procedure shown in Figure 2. The measurement results were analyzed using 2, and vibration characteristic indices (central period, distribution of story shear force in the height direction) were obtained. Coefficients showing distribution) and seismic performance evaluation indexes (horizontal strength, ultimate cumulative strength index and shape index) The product of these two factors and the seismic absorption evaluation index (hysteresis energy absorption, damage degree) are calculated. The remaining step is to calculate the structural seismic resistance index, horizontal strength ratio, and damage level to complete the process.

[0026] FIG. 4 is a flow chart showing the overall processing procedure of the method of the present invention. First, a preliminary survey of the target structure is conducted. Specifically, design drawings, calculations, expansion and renovation history, damage record, etc. We will collect documents such as the history and past seismic assessments, and install microtremor gauges through on-site surveys. Next, the measurement time, measurement time, and micromotion meter (instrument) are determined as the micromotion measurement plan. After the microtremor measurement plan is formulated, the microtremor measurement is carried out by isolating the instruments. Time alignment, micro-motion measurement, and data recording are performed, and analysis is performed to calculate time history and vibration characteristics. After the above steps are completed, the diagnostics are carried out. In this case, The current standard is based on the structural seismic index or horizontal strength ratio, and the seismic capacity is evaluated. The degree of damage is used for the evaluation.

[0027] FIG. 5 is an explanatory diagram showing the processing contents performed in the analyzer 2 by routine. For example, the input data includes each data item of the expected earthquake motion, as well as the observed microtremor time history and observed There are observation time, observation frequency band, analysis time, and analysis frequency band, and each data is an observation point attribute. The data for the structure specifications are input.

[0028] The calculation routine involves the calculation of the time history of the microtremors of interest, the division into parts, the calculation of vibration characteristic indices, Performance indices are calculated. Pre-calculation routines include FFT, filters, zero points. Corrections, root mean square calculations, center frequency calculations, and bandwidth index calculations are performed.

[0029] The display routine displays input data, observation time history, spectrum, central frequency, and In addition to displaying the band width index, vibration characteristic index, and performance index, it also displays time history and power Spectral display, trajectory display, and surface motion animation display are also performed. In the case of the application, this can be done via paper, hard devices, USB, LAN, radio waves, etc.

[0030] The outline of the method of the present invention has been explained above based on Figs. 1 to 5. The method of the present invention (MTD: Micro Tremor Diagnosis) ) measures the root mean square (RMS ), peak factor, zero crossing period, central period, bandwidth index, and reference point fine movement The energy transfer rate between the displacement, velocity, acceleration time history and the target microtremor time history is used to determine the relationship between the microtremor and the structure. Quantitatively analyze the vibration characteristics of objects. This is a method for characterizing stochastic processes using second-order moments. and correlation analysis between input and output.

[0031] In addition, in the microtremor measurement, the following is selected from the continuous measurement duration for one microtremor sensor arrangement: Several sets of time histories are extracted, and for each set the following quantities are calculated and compared against the sample mean and standard deviation: For seismic evaluation, the sample average of each quantity is used as an estimate of the expected value of each quantity. Use.

[0032] Figure 6 shows a schematic diagram of the action and force of an actual earthquake. (b) shows the spring and mass point gauge, and (c) shows the seismic force. As shown in Fig. 6(a) to (c), the surrounding ground 21 is modeled as a rigid bed, and the structure 10 is modeled as a mass point and a spring. This is the same as the current earthquake resistance standards.

[0033] The ground is constantly being affected by tides, traffic vibrations, etc., and is constantly changing in size by several microns [10 -6 The vibration is very small, about 1 / 2 inch (m). This is called micro tremor. The same is true for the surrounding ground 21 of the structure 10 shown in the solid rectangle in a). Since the earthquake enters the structure 10 and propagates within the structure 10, the structure 10 also experiences constant microtremors. Since the structure 10 and the surrounding ground 21 are subjected to random inputs for a sufficiently long period of time, It is believed to be vibrating in a vibration mode.

[0034] By installing multiple micromotion sensors (accelerometers) 1 in a structure 10 as shown in FIG. For example, as shown in FIG. 6(b), each floor of the structure 10 is connected to a mass point. In order to correspond to the modeling of the springs, one unit is installed at each representative point of each layer in a vertical array. Since the amplitude of the microtremors is small, the structure 10 will be in a stationary linear state for a finite duration. The tremor is a stationary stochastic process. c Process).

[0035] Earthquake motion is generated when the displacement caused by the destruction of rocks and ground in the source area becomes a wave and reaches the ground around the structure. Since this is a phenomenon where the source of vibration energy is different from that of constant tremors, In the narrow range, it is thought that the surrounding ground and the structure vibrate in their natural modes, so microtremors are constantly observed. It is thought to have the same vibration as From the above, the following indices are calculated by microtremor observation, and the dynamic properties of structures and earthquakes are evaluated. The behavior of the structure at that time is predicted and the current seismic performance evaluation index and new evaluation index are calculated.

[0036] 1. Central period (vibration characteristic index 1) The central period T of microseismic displacement in a certain direction at a certain point in a structure c [sec] is calculated as follows: .

[0037]

number

[0038]

number

[0039] However, ω cy [rad / sec] is the RMS of the time history obtained by differentiating the time history of any microtremor. The center frequency is calculated by dividing it by its own RMS. al frequency" is translated into Japanese as "central". It does not mean that it is specifically at the center, but rather that it is the expected value of the zero cross frequency. This refers to the frequency that plays a central role when discussing the frequency characteristics of time history in the theory of regular vibrations. ), and a (see column a in Table 1) and b (see column b in Table 1) are the displacement times, respectively. and RMS of the velocity time history.

[0040] [Table 1]

[0041]

number

[0042] Here, [0,t0] is the duration of the microtremor time history. Similarly, the central period can be defined for each of the above. The central period of the time history obtained from multiple microtremor sensors installed in a certain part of the structure is calculated. By comparing these values, it is possible to determine whether the part is vibrating in its natural vibration mode. It is possible.

[0043] 2. Expected value of coefficient expressing distribution of story shear force in the height direction (Vibration characteristic index No. 2) The current earthquake resistance and earthquake diagnosis standards for buildings are based on the mechanical model shown in Figure 6(b). , the earthquake force acting on the jth story of the building (P j ) to the seismic intensity (k j ) and its layer weight (w j ) and This is expressed as:

[0044]

number

[0045] From the above relationship, when an n-story building is subjected to the action of an earthquake and vibrates, the magnitude of the vibration generated in the i-th story is The maximum shear force that the layer can support is called the story shear force a (see column a in Table 2), and the weight that the layer can support is called the story shear force b. (see column b of Table 2) and the earthquake shear coefficient (C i ) is given as a product of

[0046] [Table 2]

[0047]

number

[0048] In addition, the seismic layer shear coefficient (C i ) with the area coefficient (Z) and vibration characteristic coefficient (R t ), mark The quasi-shear coefficient (C0) and the coefficient expressing the distribution of story shear stress in the height direction (A i ) as a product of The primary design assumes a small to medium earthquake, and the secondary design assumes a C0 of 0.2. In the next design, it has been decided that C0 = 1.0 will be used.

[0049]

number

[0050] Regarding the first layer,

[0051]

number

[0052] From the above, A i is calculated by normalizing the story shear force to the first story shear force a (see column a in Table 3). The weight of the layer above the first layer is calculated by dividing the weight of the layer above the first layer by the total weight (total weight). Quantity normalized by W and α i It can be derived that the ratio is:

[0053] [Table 3]

[0054]

number

[0055] Using the above relationship, the absolute acceleration energy transfer rate in the k direction of the i-th layer obtained by microtremor diagnosis is Assuming that a (see column a in Table 4) is preserved during elastic response due to earthquake motion input, , multiplying it by the maximum acceleration of the reference point to calculate the expected maximum absolute acceleration b (see column b in Table 4). This and the mass of each layer of the structure m j Expected maximum story shear force c (see column c in Table 4) The expected value E[A ik ] of However, the maximum acceleration of the reference point is the denominator of the rightmost side of Equation 9. The absolute acceleration energy transfer rate a (Table 4) is not shown because it is approximated. (see column a) refers to the energy transfer rate defined in paragraph "0067" of this specification, The time history of the microtremor of interest is the absolute acceleration time history, i.e., the absolute acceleration time in the k direction of the i-th layer. This is the ratio of the RMS of the time history to the RMS of the absolute acceleration time history in the k direction of the first layer. The second equal sign from the right is the equation of motion for the mechanical model of the structure in Figure 6(b) (paragraph (See "0032" to "0034"). Also, the last equal sign of number 9 is derived from the paragraph "0 The assumption stated in "021", that is, the absolute acceleration time of each layer (i-th layer) obtained by continuous microtremor observation Based on the assumption that the history can be mathematically treated as part of a stationary stochastic process, The expected maximum value over a given duration can be calculated by multiplying the RMS by a peak factor. Based on this knowledge, it is assumed that the peak factors of the absolute acceleration time history of each story are equal to each other. As described above, the method of the present invention is capable of minimizing the forces acting on the structure during an earthquake. Based on the above assumptions, the design index of the current standard, which is defined using the maximum value, is The method uses the RMS of the absolute acceleration time history of each floor. is a more stable maximum value with less variation than the method using the actual measured maximum value. In other words, we obtain an estimate of the design index.

[0056] [Table 4]

[0057]

number

[0058] Incidentally, in the earthquake resistance standards, based on various analyses and considerations, α appearing in the above two formulas is as follows: i (standardized weight), and the first natural period T of the building are used as parameters. i It stipulates:

[0059]

number

[0060]

number

[0061] However, T [sec] is the value for λ, where the majority of the columns and beams of the building are made of wood or steel. The ratio to the total height of the floors (excluding the basement) h [m] is calculated using the following formula: It is being done.

[0062]

number

[0063] The above regulations are based on the maximum load of each floor of a tower-like structure, from low-rise to super-high-rise. Answer: It is said that it was devised to express the shear force distribution in one formula. In the earthquake standard, the above formula is used. i Instead of calculating the b) Create a model and calculate the maximum value of the story shear force using a method such as time history response analysis. i of You are also allowed to ask.

[0064] 3. Expected value of average transmissibility and response magnification (Vibration characteristic index 3) In the model of Figure 6(b), when considering the action of an earthquake on the i-th layer, the layer supports Give the RMS or maximum value of the average acceleration, average velocity, etc. of part b (from the i-th layer to the n-th layer). It is useful to use the following indicators:

[0065]

number

[0066]

number

[0067] Here, mj is the mass of the jth layer, a (see column a in Table 5), and b (see column b in Table 5) are are the energy transfer rates of acceleration and velocity in the k direction of the jth layer, respectively, and B aik Add the average Velocity energy transfer rate, B vik is called the average velocity energy transfer rate. The gear transmissibility is the ratio of the RMS of the microtremor time history of interest to the microtremor time history of a reference point. In the present study, it is assumed that this is preserved at the time of maximum elastic response due to earthquake motion input, and the peak factor is appropriately set. Assuming that the maximum response of the time history is calculated by multiplying the maximum input value of the reference point by the energy transfer rate. Calculate.

[0068] [Table 5]

[0069] For example, using the above average acceleration energy transfer coefficient, Absolute acceleration time history a of each point (mass dM) of part b k The spatial average value of (t) in the k direction, A k (t) RMS expectation E[σ Ak ] according to the acceleration time history a of the reference point (see Table 6) It can be calculated as follows:

[0070] [Table 6]

[0071]

number

[0072]

number

[0073] Expected value A of the coefficient expressing the distribution of story shear force in the height direction in Equation 9 imk and is defined in Equation 13. Average acceleration energy transfer rate B aik There is the following relationship between:

[0074]

number

[0075] That is, A imk is the average acceleration of the part supported by the focus part i and the part supported by the first layer. It can be said that this is the ratio of the average acceleration (of the entire structure). In Equation 13, the average acceleration transmissibility B when j=1 aik is the mean absolute acceleration of the structure The ratio of the absolute acceleration of the reference point (see column a in Table 7) to the absolute acceleration of the reference point (see column b in Table 7), i.e., the ratio of the absolute acceleration of the entire structure Acceleration response magnification R when the body is reduced to a single degree of freedom system as shown in Figure 7 amk is the expected value of .

[0076] [Table 7]

[0077]

number

[0078] Similarly, B with j=1 in Equation 14 v1k is when the entire structure is reduced to a single degree of freedom system. This can be said to be the expected value of the speed response magnification.

[0079]

number

[0080] The current standard standard shear coefficient in Equation 6 is C0=0 for the primary design assuming small to medium earthquakes. .2 In the secondary design for large earthquakes, C0 = 1.0 is used because The maximum acceleration of vibration is 0.07G~0.08G for small and medium earthquakes, and 0.33~0.4G for large earthquakes. G, and the acceleration response magnification of a short-period building is considered to be 2.5 to 3. .

[0081] 4. Expected horizontal strength (earthquake resistance performance index 1) In the earthquake resistance standard, each story of the structural model of the building is i The distributed shear force is gradually increased and loaded. The story shear force a (see column a in Table 8) acting on the i-th story when the i-th story yields is It is defined as the horizontal strength b (see column b in Table 8). The relationship between the story shear force and the acceleration of the reference point caused by the ground motion in the structure is as follows: The average acceleration transmissibility (B aik ) by The relationship between the story drift and the acceleration at the reference point is defined in paragraph "0067" of this specification. Using these, when the structure responds linearly, When the maximum value of the story displacement of the i-th story reaches the yield displacement, the expected value of the story shear force can be calculated. This is the expected horizontal strength c (Table 8) assuming that no yielding will occur except for the i-th story. (see column c) Acceleration d in the k direction of the reference point (see column d in Table 8) versus story drift in the k direction of the i-th story (e ik (t)) energy transfer rate e (see column e in Table 8) as the ratio of their RMS It is defined as follows:

[0082] [Table 8]

[0083]

number

[0084] Maximum story drift e ikmax is the yield displacement e ikY of the acceleration of the reference point when it reaches The maximum value is a ikY So,

[0085]

number

[0086] The expected maximum value of the story shear force at this time, a (see column a in Table 9), is the part supported by the i-th story. The expected maximum average acceleration of mass b of b (see column b of Table 9) is A bkmax It can be calculated by multiplying.

[0087] [Table 9]

[0088]

number

[0089] The expected value of the maximum acceleration of the reference point and the maximum value of the average acceleration of part b above is the average acceleration energy Energy transmission rate B aik are related using

[0090]

number

[0091] From the above,

[0092]

number

[0093] From formula 21 and formula 24,

[0094]

number

[0095] Expected value of story shear coefficient when ultimate horizontal strength is reached C uikm The relationship in Equation 5 is This is obtained by dividing the above formula by the weight that the layer supports.

[0096]

number

[0097] However, the height of the i-th floor in the k direction is H 0ik [m], yield deformation angle is R Yik [rad], g[ m / sec 2 ] is the gravitational acceleration. Also, the shear stress of the first story when it reaches the horizontal bearing capacity is Expected value of shear coefficient, i.e., expected value of base shear coefficient C ui1km From the relationship in Equation 8, , the above formula is A i This can be calculated by dividing by . , acceleration response magnification R amk and the energy transfer coefficient a of the inter-story drift with respect to the acceleration at the reference point (Table 10).

[0098] [Table 10]

[0099]

number

[0100] The horizontal bearing capacity ratio is the expected value of the horizontal bearing capacity obtained above, which is the required guarantee specified by the seismic standards. Calculate by dividing by the horizontal strength.

[0101] 5. Expected value of the product of ultimate cumulative strength index and shape index and structural seismic index (seismic performance index part 2) ) The seismic assessment standard is for the beams and girder direction (horizontal) of each floor (each story) of a mid- to low-rise RC building. 2 directions) Structural seismic index I s The basic performance index E0 and the shape index S D , and the aging index T.

[0102]

number

[0103] Regarding the basic performance index E0 in the above formula, the strength index in each direction of each column, wall, and beam of each story ( A detailed formula is prescribed for calculating the product of the strength index (C) and the toughness index (F). Theoretically, the basic performance index E0 is the product of the strength index and toughness index of that layer (E0 = The toughness index of a layer is the ratio of the interlayer deformation at which the layer reaches its ultimate limit. Since this is the equivalent toughness index, we call it F U and accordingly, the layer reaches its ultimate limit. The coefficient equivalent to the base shear coefficient for the story drift angle (ultimate cumulative strength index) is C TU Expressed as .

[0104]

number

[0105] From the above relationship,

[0106]

number

[0107] Equation 29 is the line plotted in Figure 8 for the story shear force a (see column a in Table 11) versus the story displacement e. In this case, the yield point Y and the ultimate The story shear force (cumulative strength index) at point U is equal to (C TY =C TU ), yield correlation displacement (e Y ) is the cumulative strength index for the story shear force a (see column a in Table 11). Weight supported by the layer Σw and distribution coefficient A of the layer shear force in the height direction i Divide by the cumulative strength index C T The story drift e is divided by the story height H0 to obtain the story drift angle R. The i is omitted.

[0108] [Table 11]

[0109] The relationship between story displacement and story shear force obtained by microtremor diagnosis is near the origin of the relationship in Figure 8. The seismic assessment standard assumes that the relationship between the age index T and the ductility index F U When the standard earthquake motion (standard earthquake motion: G0) is assumed, the floor If the layer reaches the final state, the I S The value is set to 0.6. Correlation displacement energy transfer rate h obtained by dynamic diagnosis egi corresponds to the design earthquake motion (G0) Multiplying the reference point displacement, the expected value of the correlation displacement (E[e G0 ] ) is calculated as , yield displacement (e Y =R Y H0), the value is 0.6. 0 for F U If =1,T=1, then

[0110]

number

[0111] Since it is assumed that the cumulative strength index and the story drift angle (story displacement) are proportional, The amount obtained by multiplying the cumulative strength index at the end of the TU S D ) ik The expected value of Correlation displacement energy transfer rate h obtained by dynamic diagnosis egik corresponds to the standard earthquake motion (G0) Reference point displacement x G0

[1978] to obtain the correlation displacement (e G0ik ) and use this to calculate the descending Deformation (e Yik ) and multiplying it by 0.6.

[0112]

number

[0113] Now, according to the earthquake resistance assessment criteria, s The value of =0.6 is based on the Tokachi-oki earthquake of 1968, Buildings that sustained moderate or severe damage in the 1978 Miyagi Prefecture earthquake s Estimates of value distribution and earthquakes I. Buildings that have not experienced damage s The validity was verified by comparing the value distribution. In addition, there were earthquakes in the vicinity of Izu Oshima in 1978 and off the east coast of Chiba Prefecture in 1987. The book includes information on the 2011 Great East Japan Earthquake and Tsunami, as well as the 1978 Miyagi Prefecture offshore earthquake. The observed seismic motion up to the earthquake and the observed seismic motion in the 21st century, represented by the Great East Japan Earthquake in 2011, The maximum acceleration, velocity, duration, etc. are on a completely different level, so the seismic motion assumed by the diagnostic criteria is I would like to think that this is the seismic activity that existed up until 1978, when the standard was first established.

[0114] The records of strong earthquakes observed in Japan up until 1978 are compiled by the National Oceanic and Atmospheric Administration (NOAA). The results of statistical analysis of this data indicate that the earthquake motions at that time were roughly The expected maximum displacement is thought to be about 2.5 cm in both horizontal directions. Substituting into Equation 32. Also, the yield displacement e of the i-th layer in the k direction in the same equation Y[m] to floor height H0 [m] and yield deformation angle R Y [rad], and the ultimate cumulative strength index and shape are calculated from the energy transfer rate. We obtain the formula for calculating the expected value of the product of the indices.

[0115]

number

[0116] From Formula 30 and the above formula, the structural seismic index I s can be calculated from microtremor diagnosis.

[0117]

number

[0118] However, I sm is the structural seismic index obtained from microtremor diagnosis, F U , and T are the ultimate toughness index and It is also a longitudinal indicator.

[0119] 6. Hysteretic energy absorption (seismic performance index 1) Nonlinear response calculation, i.e., after a certain layer of the structure reaches its yield strength, i.e., in terms of stress Design how the structure will deform and move under the action of an earthquake after it becomes nonlinear From the information written in the book or the information to be written in the book, it is possible to calculate the earthquake Even if the structure and ground are simplified as shown in Figure 6(b) or Figure 7, There is none.

[0120] There are many models (constitutive laws) for the stress and strain acting between each layer of a structure after yielding. Concrete and soil exhibit nonlinearity even with very small strains. In addition, variables that explain nonlinearity include not only the story displacements shown in Fig. 8, but also their correlations. Velocity, absolute acceleration, and stress in other directions such as axial force, strain, etc. can be considered. The components that make up the layers, the materials that make them up, and the connection conditions of each component are diverse. There are many ways to reduce it to a single constitutive law, and it is difficult to say which is the correct answer.

[0121] In seismic design, there are several representative nonlinear models, It is used to analyze the results of experiments using a full-scale model, but the method of applying force and measuring displacement, etc., of the experimental device are unclear. Even if the method is suitable, it is difficult to verify its effectiveness in the action of an actual earthquake in three-dimensional space. It is not possible.

[0122] Figure 9 shows the relationship between friction type interlayer shear force and support part acceleration, and Figure 10 shows the friction type interlayer shear force Fig. 10 shows the relationship between the friction-type inter-story shear force and the inter-story displacement. The diagnosis measures the vibration of representative points of each story of the actual structure and compares it with the structural model in Figure 6(b). The response characteristics of each layer can be quantified. From the results, the following results are obtained: The expected value of hysteretic absorbed energy can be calculated using the friction model.

[0123] This model is a stress model for a structure in which stones are piled up, and is shown in Figs. 9 and 10. As shown in the figure, the absolute acceleration of the part supporting the story exceeds the critical acceleration, and a relative velocity occurs between the stories. When the fluid moves, a constant shear force acts in the opposite direction to the fluid velocity.

[0124] Starting from zero story displacement, the story displacement increases in a certain direction until it reaches a certain magnitude. By the way, when the structure deforms so that the story displacement continues to decrease, Now, if we plot the relationship between the story displacement and the deformation of the structure, which increases as shown in Figure 11, In the bilinear shear force vs. story displacement relationship shown in Fig. 8, the inter-story shear The relationship between shear force and acceleration of the support part is shown in Figure 9. In the interfacial displacement relationship, the part where the shear force is constant (line segment YU in Figure 8) is The rule can be applied.

[0125] The hysteretic absorbed energy W of the i-th layer calculated from the k-direction component ik The structure is as shown in the formula below. The upper surface of the i-th layer of the structure moves relative to the lower surface (inter-story displacement e ik ) to cause Work done by restoring force (story shear force) a (see column a in Table 12) W ik and the increment (Table 12 (see column b) over the vibration duration t0.

[0126] [Table 12]

[0127]

number

[0128] The spatial average absolute acceleration and mass in the k direction of the part supported by the i-th layer are respectively expressed as A ik ( t), (Σm), then the equation of motion in the k direction of the part supported by the part of interest is as follows: become.

[0129]

number

[0130] Since the restoring force is assumed to have the yield limit strength a (see Table 13), from Equation 36, A ikIt can be seen that (t) also has a limit value, and this is called the limit acceleration A cik Let us assume that.

[0131] [Table 13]

[0132]

number

[0133] Microtremor observations show that when a structure responds elastically, that is, when the restoring force does not have a limit value, The spatial average acceleration of the part supported by the i-th layer can be predicted, so let this be a (see Table 14). do.

[0134] [Table 14]

[0135] When the restoring force is of friction type and the bottom surface of the layer vibrates with acceleration a (see Table 14), The hysteresis absorption per unit mass when the reference (ref) is part of a stationary Gaussian process of duration s0 is Energy harvested W ik The expectation value of is obtained from the power spectral density function of a (see Table 14). Each parameter and the critical acceleration A ci The theoretical equation expressed as follows has been obtained from random vibration theory.

[0136]

number

[0137] Where: E[*]: Expected value of * [operator]

[0138] In addition, for the k direction of the i-th layer a (see Table 15): Restoring force [N] eik (t): Relative displacement of the upper and lower surfaces [m] A cik :Limit acceleration [m / sec 2 ] Σw: Supported weight [N]

[0139] [Table 15]

[0140] In addition, the spatially averaged elastic response acceleration time history a of the part supported by the i-th story during an earthquake (see Table 14) ), and the k-component of the velocity time history integrated from this: s0: Strong earthquake duration [sec] T vik : Central period of velocity time history [sec] σ aik : RMS of acceleration time history [m / sec 2 ] α vik : Bandwidth exponent of velocity time history [dimensionless] σ vik :RMS of velocity time history [m / sec]

[0141] However, the strong earthquake duration s0 is the time history of the duration t0 that has non-stationary characteristics such as earthquake motion. Let (x(t)) be a succession of stationary Gaussian processes (G(t)) with the same power spectral density function. The maximum value of x(t) is the duration of G(t) that is treated as part of the duration s0. The maximum value is set to occur on average once during the duration s0.

[0142] Above T vik The following parameters are the time history and energy transfer rate obtained from microtremor observations, and It is calculated from the predicted maximum value of the vibration time history of the reference point due to the assumed earthquake. Even during an earthquake, it is assumed that the structure will vibrate in the vibration mode obtained from the microtremor observations during elastic response. (See column a of Table 16)vik , bandwidth exponent α vik is supported by the i-th layer Calculated using the micro-tremor acceleration time history b (see column b in Table 16) of the bottom surface of the part, i.e., the top surface of the i-th layer In addition, the RMS σ of c (see column c in Table 16) vik and the RMS σ of this velocity time history v ik Regarding the average transmission coefficient of each layer (j=i...n) (paragraphs "0059" to "0 075") and the RMS of the reference point at the time of the earthquake.

[0143] [Table 16]

[0144]

number

[0145]

number

[0146] The RMS of the acceleration and velocity during the earthquake at the reference point is calculated using the peak factor. The expected maximum velocity at V maxk and the expected maximum acceleration A maxk Rewrite it to a relationship with It is possible.

[0147]

number

[0148]

number

[0149] Furthermore, the critical acceleration in the k direction of the i-th layer is as described in paragraphs "0081" to "0100" of this specification. The horizontal bearing strength a (see column a in Table 17) is the yield story shear strength (a (see column b in Table 17) ) is calculated by using the fact that it is equal to .

[0150] [Table 17]

[0151]

number

[0152] From the above, the expected value of the hysteretic absorbed energy of the i-th layer due to a large earthquake calculated from the k-direction component is W mik [Nm] can be calculated as follows:

[0153]

number

[0154] where the yield displacement e ikY is expressed as the product of the yield deformation angle and the story height. Regarding the direction, R Yik : Yield deformation angle [dimensionless] H 0ik :Standard floor height [m] a (see Table 18): Inter-story displacement energy transfer rate for reference point acceleration [dimensionless]

[0155] [Table 18]

[0156] In addition, regarding the k-direction component of the microtremor time history on the upper surface of the target area, T vik : Central period of micromotion velocity time history [sec] α vik : Bandwidth exponent of microtremor velocity time history [dimensionless] However, the bandwidth index is calculated by dividing the central frequency of the time history by the central frequency of the differential time history. The bandwidth index of the microtremor velocity time history is calculated by the central frequency of the microtremor velocity time history and the microtremor acceleration is the ratio of the central vibration frequency of the vibration time history.

[0157] In addition, regarding the part supported by the layer, Σm: Mass [kg] B aik : Average acceleration transmissibility (see formula 13) [dimensionless] B vik : Average speed transmission ratio (see formula 14) [dimensionless]

[0158] Furthermore, for the k-direction component of the large earthquake motion at the reference point, the following parameters are related to the input magnitude: The properties are determined by the designer's judgment or by standards. s0: Strong earthquake duration [sec] V maxk :Maximum speed [m / sec] A maxk :Maximum acceleration [m / sec 2 ] Gamma v : Peak factor of velocity time history [dimensionless] Gamma a : Peak factor of acceleration time history [dimensionless]

[0159] In addition, both sides of the above equation are divided by Σm / 2 to obtain the hysteretic absorbed energy per unit mass supported. The expected value of the speed conversion value V mik Get [m / sec].

[0160]

number

[0161] 7. Damage level (seismic performance index 2) The degree of damage to a certain layer of a structure due to the action of an earthquake is proportional to the hysteretic absorbed energy. The ratio of the limit value to the damage level (I d ) and can be used as a design guideline.

[0162]

number

[0163] where for the ith layer in the k direction: I dik :Damage degree [dimensionless] W mik : Expected value of hysteretic absorbed energy [Nm 2 / sec 2 ] W lik : Limit value of hysteretic absorbed energy [Nm 2 / sec 2 ]

[0164] Limit value of hysteretic energy absorption W lik is the restoring force of an individual member or group of members. Assuming that the bilinear type is as shown in Figure 8, the respective limit values ​​are cumulatively calculated. This can be done.

[0165]

number

[0166] However, the limit value is twice the area of ​​the projection of the line segment OYU onto the horizontal axis in Figure 8. The energy absorbed in this n kj The calculation is based on the assumption that the number of Then, for each individual member or member group j in the k-direction of the ith story: n kj : Limit number of repetitions [dimensionless] q kj :Strength [N] F jk :Toughness index [dimensionless] e Yj : Yield displacement [m] RYik : Yield deformation angle [rad] H 0ik :Floor height [m]

[0167] The expected value of the yield shear strength (horizontal strength) of the i-th story in the k-direction is as described in paragraph "008" of this specification. Since it is calculated from "1" to "0100", if you give the layer toughness index and the limit number of repetitions, The limit value of the hysteretic energy absorption can be calculated by the formula 47. Using the formula 25,

[0168]

number

[0169] However, for the i-th layer in the k-direction N ik : Limit number of repetitions [dimensionless] a (see column a in Table 17): expected value of yield shear strength (horizontal strength) [N] F uik : Toughness index [dimensionless] Σm: Mass of the supported part [kg]

[0170] The damage level is calculated as the quotient of the expected value of the hysteretic absorbed energy in Equation 44 and the limit value in Equation 48 as follows: Calculate as follows.

[0171]

number

[0172] Damage degree I dik is the vibration obtained from microtremor observation of the ground system around the structure in the k direction of the i-th layer. Average acceleration transmissibility B of the part that supports this characteristic aik , average velocity transmission rate T vik , and Inter-story displacement energy transfer coefficient a in the k direction of the i-th story against the reference point acceleration (see Table 20), velocity Central period T of time historyvik , and the bandwidth exponent α vik The input earthquake motion characteristics are expressed as strong earthquake motion. Duration s0, maximum speed V maxk and maximum acceleration A maxk and their respective peak factors Tar γ v , γ a In addition, as a structural parameter, the yield deformation angle R Yi k , and standard floor height H 0ik The recovery performance is measured using the toughness index F uik and limit repetition Number of times N ik It is expressed as:

[0173] 8. Seismic assessment standards, current standards, and earthquake motion levels in line with recent earthquake environments In the microtremor diagnosis (MTD2017), the vibration amplification characteristics of a structure are estimated from the observed microtremor time history. The energy transfer rate is quantified as a sample average. The vibration modes are also visualized and the specific The period and bandwidth are measured. For the earthquake resistance evaluation, The vibration caused by a large earthquake at the reference point is used as input, and the maximum elastic response is estimated from the energy transfer rate. Calculate the expected value of the structural seismic index. Also, calculate the average weighting of the part supported by the target layer or part. The speed and the historical absorbed energy are estimated from the predicted speed, and the damage degree is calculated. The setting of earthquake motion levels is at the discretion of each designer, but the assumed levels of the current standards, etc. are included in the microtremor diagnosis. It is effective to convert it into a force value and display it.

[0174] Table 19 shows the diagnostic criteria and the standard earthquake motion levels that are considered to be assumed by the current standards ( Expected maximum acceleration, velocity, displacement (Amax, Vmax, Dmax) and duration of strong earthquakes The expected value of the earthquake motion (S0) is shown at the bottom. As for the diagnostic criteria, as mentioned above, the standard for This is an estimate based on observed earthquake motion. The story of the person and the notice spectrum (2015 edition of the Building Structural Related Technology Published by the National Official Gazette Sales Cooperative Association) The estimate is based on the shape of the earthquake motion observed recently. It was estimated from the strong earthquake observation records of the 2011 Tohoku Pacific Ocean Earthquake and the 2016 Kumamoto Earthquake. However, no statistical processing has been carried out. In addition, the earthquake motion level in the recent earthquake environment is one order of magnitude higher than the current standard level, and It is used as the input earthquake motion for the current criteria framework based on maximum response and the framework for microtremor diagnosis. Seismic design for this level of earthquake motion is carried out in a fundamentally different way than in the current law. It is necessary to do so.

[0175] [Table 19]

[0176] Positioning of Micromotion Diagnosis In rational seismic design, microtremor diagnosis plays the following roles:

[0177] (1) Post-completion inspection and additional countermeasures After the structure is completed, a microtremor diagnosis is carried out to determine the vibration mode and vibration period (T c ), story shear force Distribution coefficient (A im ), response ratio (R amk , R vmk ), cumulative strength index a (see Table 20) , damage degree (I dm ) and compare it with the design calculation to confirm the validity of the calculation and construction. In addition, if necessary, additional countermeasures will be implemented. Note that the above indicators are calculated for the entire structure. In both cases, the vibration characteristics of each part will be determined by installing a vertical array measurement in that part.

[0178] [Table 20]

[0179] (2) Periodic health checks and repairs When microtremor diagnosis is carried out periodically and the indicators in the previous section are measured, deterioration of the structure is found. After the repairs are completed, microtremor diagnosis will be carried out again to confirm the effectiveness of the repairs.

[0180] (3) Diagnosis and seismic reinforcement of existing structures Conduct microtremor diagnosis on existing structures built under current or previous earthquake resistance standards, and if necessary In addition, measurements and inspections are carried out before and after reinforcement to determine the effectiveness of the reinforcement. Check quantitatively.

[0181] (4) Analysis of the relationship between earthquake damage and vibration characteristics of the ground and structures As an example, a building that underwent microtremor diagnosis was damaged by an earthquake, and the relationship between the degree of damage and the diagnosis index was examined. The relationship will be analyzed and used to revise future design methods, diagnostic methods, and standard values ​​for each indicator. EXAMPLES

[0182] 1) Target facilities and measurement methods Completed in 1972, it has one basement floor, four floors above ground, and a total floor space of 838 m 2 (X direction 1 1. RC hospital building (4th floor is steel, tentative name Y Hospital) The 12th to 4th floors 15 are as shown in Figures 12 to 15. The results of the microtremor diagnosis were presented below. A seismic assessment was conducted in April 2014. A reinforcement plan was drawn up to raise the value above 0.6, but construction work could not be carried out while the hospital was in operation. In order to prevent the building from collapsing, the SRF method (wrapping with polyester fiber belts) was adopted. The "axial strength reinforcement" method, which reinforces the main columns using the "reinforced concrete method" (see paragraph "0194" of this specification), is used. It has been done.

[0183] Microtremor observations were carried out using four microtremor meters21 in four different arrangements as shown in Figures 12 to 15. In the first (measurement 1) and second (measurement 2) measurements, the A2 passages on each floor from the first floor to the fourth floor were In measurement 3, one each of the A4 and A5 sheets was installed in a vertical array. The sensors were installed at A4 on the first floor and A2, A4, and B1 on the second floor. They were installed at four different points and at A2, A4, and B1 on the third floor.

[0184] The measurements took about two hours, and consisted of setting up the instruments, taking five minutes of continuous measurements, and then rearranging the instruments. Measurements and removals are carried out using four types of instruments. The training was conducted on the 8th from 3pm to 6pm while the hospital was in operation. After the reinforcement, The reinforcement work will be carried out from 2 p.m. to 4 p.m. on the 2nd. The construction period is from July 20 to September 3, 2017. However, as of August 8, no construction has been carried out and only preliminary preparations have been made. As of September 22nd, the structural work was complete with only minor finishing touches remaining.

[0185] The microtremor diagnosis was carried out by dividing the total recorded time history of the five minutes observed at each point into approximately one minute segments. Divide it into 5 to 7 parts with some overlapping, and calculate each index for each part. The average value and standard deviation were calculated for each measurement. The average values ​​are shown in the tables following Table 21. The above measurements were taken before and after the reinforcement work using the SRF method. After reinforcement, we examined the effect of the reinforcement.

[0186] The micromotion meter measures the acceleration time history and uses a 10Hz high-cut filter and a 0.2Hz After using a low-cut filter (4th order Butterworth), the velocity and displacement were linearized using the acceleration method. The results were obtained by numerical integration. Figures 16 to 22 show the floor plans and framework diagrams of the target buildings. Expansion joints are installed on the street. Seismic assessment is carried out on streets 1 to 4. The diagnostic results cited in this specification are 1 to 4' The results are based on the data up to this point.

[0187] 2) Performance indicators Table 21 shows the expected value of the cumulative strength index (C T S D ) mik Before and after reinforcement The value was obtained from the seismic diagnostic calculation. TU S D Measurement 1 is a vertical alignment of A2. Array 1 and Array 2 show vertical arrays of A4 size paper. Table 22 shows the change rate before and after reinforcement and the calculation results. Tables 23 and 24 show the comparison of the standardized input energy with the reinforcement value. The value W obtained from the front and rear micromotion diagnosis Komik and the calculated value W Koik and the change before and after reinforcement The expected damage rate and the calculation are shown in Tables 25 and 26. d0m ) before and after reinforcement and calculated values ​​(I d ) and a comparison with calculations before and after reinforcement is shown. The value in parentheses is the value considering the second type structural element. The limit value of energy is calculated from the strength and toughness of the member group calculated by seismic diagnosis using Formula 47. The hysteretic absorbed energy was calculated using a simplified formula (see paragraph "0199 In addition, in this calculation, the critical acceleration used to calculate the hysteretic absorbed energy is calculated. In determining the horizontal load-bearing capacity of a structure (see paragraph "0149" of this specification), the cumulative strength index is used instead of the horizontal load-bearing capacity. The product of the mark and the shape index (see Equation 32) is used.

[0188] [Table 21]

[0189] [Table 22]

[0190] [Table 23]

[0191] [Table 24]

[0192] [Table 25]

[0193] [Table 26]

[0194] The reinforcement work consisted of installing high ductility polyester fiber materials (Bessel-type materials) on the main pillars of each floor from the first to the third floor. The method used was to secure shear strength and axial strength by wrapping reinforced concrete (SRF) around the structure. The reinforcement design is such that the inspection ratio of all columns exceeds 1.0. The maximum value of the axial force test ratio is the collapse risk value (I f The design guideline for reinforcement to prevent collapse is called the "value". The two right columns of Table 25 show the I before and after reinforcement. fIn the calculation, the axial strength of the column is Since this is the remaining axial strength at the time of large deformation (F>3.0), for RC columns, it is zero before reinforcement. Collapse risk level I f is infinite.

[0195] Looking at the diagnostic calculations on the right side of Table 21, before and after reinforcement, the reinforcement work has reduced the area of ​​the floor space, except for the X direction on the first floor. Cumulative strength index C TU S D This is because the wall with columns or the columns with sleeve walls This is because the pillars were wrapped around slits. However, after reinforcement, C TU S D Before reinforcement, The strength and toughness of the reinforced members were reflected in the fracture results, and the groups were regrouped and tabulated. This is an approximate calculation. The shape index S D does not take into account changes in The decrease in strength index due to reinforcement work is due to the fact that the strength in the Y direction is considered to be sufficient in this reinforcement design. This was the result of aiming to ensure axial strength and prevent collapse even if the strength was reduced slightly. In addition, as shown in Tables 25 and 26, damage level I was reduced by reinforcement. d Before reinforcement, it was about 20-30% After reinforcement, the value was below the standard value of 1.0 for all floors and directions. This indicates that the damage was within the acceptable limits.

[0196] Cumulative strength index C according to diagnostic calculations shown in Tables 21 and 22 TU S D and obtained by micromotion diagnosis The expected value of the cumulative strength index (C T S D ) mik Let's compare the values ​​before and after reinforcement. Regarding the tremor diagnosis, the value on the 3rd floor was about 40% lower, but the values ​​on the other floors and directions were almost the same. On the other hand, in measurement 1, the first floor was almost the same, but the microtremor diagnosis results on the second and third floors were This is a significantly smaller value, about 20% of the diagnostic calculation. It is believed that this reflects the structural characteristics of the surrounding area. Measurement 1 (2-way) X direction is a frame with almost no walls. Also, the opening of the wall of the adjacent street The X direction of the measurement 2 (4th) is almost entirely made up of walls. The same is true for the adjacent 4' frame. Measurement 1 (2-way, A-way) Y direction is either wall-free or The opening is large. On the other hand, in the Y direction of measurement 2 (4 passages, A passage), there is an opening but a wall is attached. This is also reflected in the shape indexes of the seismic assessment. S D The value of 0.63 is small on the second and third floors in the X direction. In the vicinity of the second passage, the inter-story displacement in both the X and Y directions is large.

[0197] Looking at the rate of change before and after reinforcement in Table 22, in measurement 1 (around 2 letters), (C T S D ) mik but The improvement is almost uniform, about 20%. This is due to the column reinforcement of the SRF method shown in Figures 16 to 22. By this, the X-direction frames 1 to 3 at the center of the pillar and the A-frame in the Y-direction near the 2nd path This is the result of improving the vibration characteristics of the building and reducing the inter-story displacement due to the design basis earthquake motion. On the other hand, in measurement 2, there was almost no change before and after reinforcement, (C T S D ) mik The number of cases is decreasing. However, looking at the absolute values ​​in Table 21, in measurement 2, after reinforcement, the values ​​are 1 in both the X and Y directions. The values ​​are consistent, at around 0.5 to 0.6 on the second floor and around 0.2 on the third floor. Similarly, the first floor is about 0.6, and the second and third floors are about 0.2. It is believed that this is the result of reinforcing the main pillars with this material, which stabilized the seismic characteristics.

[0198] Comparing the magnitude of the diagnostic calculations shown in Table 22 with the values ​​obtained by microtremor measurements, On the first floor, the calculated and measured values ​​are almost the same for measurements 1 and 2. This is because the microtremor diagnostic method and setting the expected maximum ground surface displacement due to earthquake motion assumed in the seismic diagnosis (paragraph (see "0113" to "0114") was appropriate in this example. On the second and third floors, which are eccentric, the values ​​measured in measurements 1 and 2 were significantly different. This is an example showing that direct array observations can reveal detailed structural characteristics.

[0199] Standardized input energy W shown in Table 23 K0ik and the allowable limit value W l0ik Looking at the structure, Published by the Construction Quality Assurance Institute: 2015 edition, SRF construction method design and construction guidelines and explanations, p. 112 Standardized hysteretic absorbed energy (hereinafter referred to as standardized input energy) W E In the simplified formula The effect of earthquake motion and structures on input energy is a uniform coefficient m E = 5.0 Therefore, the input energy is calculated to be unchanged before and after reinforcement. As shown in Equation 49, the effect of the strength of the structure, the response magnification, and the vibration bandwidth is considered. Since the formula reflects the effect of reinforcement, the results change before and after reinforcement. W of the book E A i The value is multiplied by and displayed as a value normalized only by the supporting mass.

[0200] The absolute value of the standardized input energy is the value of measurement 1 before reinforcement, which is greatly affected by eccentricity. In the X direction, the measured values ​​are 4 to 7 times larger than the calculated values, but the rest are almost the same. Therefore, this example is equivalent to the microtremor diagnostic method and the current standard shown in Table 19. This shows that the set earthquake motion levels are appropriate in terms of the degree of damage.

[0201] Looking at the rate of change in standardized input energy before and after reinforcement shown in Tables 23 and 24, For measurement 1, which has a large impact, the reduction is uniform, at about 60%. On the other hand, for measurement 2, X The first and second floors in both directions show a large decrease, but the third floor shows an increase in both directions. The increase in the Y direction of 2 is about 7 times larger. Front and rear strength (C T S D ) mik That is, this example reflects the change in the standardized input In calculating the energy limit acceleration, a cumulative strength index is used, so the increase in this strength However, although the increase rate in the Y direction is large, the absolute value itself is Not larger than the tolerance.

[0202] Let us look at the damage levels shown in Tables 44 and 45. In the calculation, before reinforcement, the damage was in the X direction. However, after reinforcement, it falls below the standard value of 1.0 in both the X and Y directions (damage falls below the allowable value). ) results. According to the micromotion diagnosis, except for the X direction of measurement 1, which is affected by eccentricity, It is below the standard value. The Y direction on the 3rd floor of measurement 2 is 1.16, which is almost the standard value. You can think about it.

[0203] Based on the above, if this building encounters a major earthquake as envisaged by the current standards, there are two ways around it. Vibrations in the X direction may cause damage beyond the allowable limit, but no damage to other parts. It can be said that there is a high possibility that the value will be within the allowable limit. Collapse risk level I shown in 4 f Since the standard value is 1.0 or less after reinforcement, the current standard is It is believed that the building will avoid collapse even if it receives an earthquake motion that exceeds its width.

[0204] 3) Coefficient A expressing the distribution of story shear force in the height direction i Table 27 shows the coefficient A, which represents the distribution of story shear force in the height direction. i The expected value of (A imk ) Reinforcement The absolute acceleration energy transfer rate a obtained by microtremor observation is calculated by Equation 9. (See Table 4) and the mass of each layer of the structure m j The calculation is done by the current standard formula (Formula 1 0), and Table 29 shows the rate of change before and after reinforcement and the ratio of calculation to actual measurement. It shows.

[0205] [Table 46]

[0206] [Table 47]

[0207] [Table 48]

[0208] Let's look at the actual measurements before and after reinforcement. In measurement 1, the maximum values ​​for each floor and each direction were In measurement 2, the temperature on the 3rd floor increased by 10% to 20%, but the temperature on the 2nd floor increased by 10% to 20%. The change is less than 5% on the second floor. Looking at the ratio of calculation to actual measurement, the measurement points, reinforcement, and non-reinforcement on the second floor On the other hand, on the third floor, before reinforcement, the actual values ​​were higher than the calculations in both measurements 1 and 2. The measured value is about 10% smaller, and after reinforcement, the measured value and the calculated value match in measurement 2, or 1 in the Y direction. It is about 0% larger.

[0209] Looking at the absolute values ​​of the above figures, the actual measurements and calculations are almost the same. This is because The maximum value of the coefficient representing the distribution in the height direction was calculated based on the microtremor measurement method. This shows that the uniform distribution of seismic intensity, which is thought to be the distribution of response layer shear stress, was observed. In addition, the changes before and after the reinforcement of the third floor and the comparison with the calculations showed that the strength of the third floor was particularly increased by the reinforcement work. The effect of correcting the large size by cutting slits to bring it closer to the second floor and below is apparent. It is believed that this is the case.

[0210] For the Y direction on the 3rd floor of measurement 2, the actual A i (A imk ) is much larger than calculated. The reason is that the slits in the structure increase the vibration of this part. This shows that the actual measured values ​​of the strength index (C T S D ) mik of Decreased (0.60 → 0.20), standardized input energy W shown in Table 23 K0ik Increase in ( 5.4 → 37.9), and damage level I shown in Table 25 d0ik Increase (0.80→1.16 However, after cutting the slits, the pillars were wrapped with the SRF method. In the table, the risk of collapse is below 1.0 for each floor. It was confirmed that the damage level in the vicinity of measurement 2 was almost below the standard value (1.0) on each floor. Also, in the vicinity of measurement 1, the Y direction is below 1.0. Regarding the prediction of damage in one direction to a certain extent, the seismic covering was applied to one type of wall using the SRF method. It is effective to absorb the vibration energy by strengthening the structure. From a damage control standpoint, we would like to implement the above measures in future construction works.

[0211] 4) Average acceleration, average velocity transmission rate B aik , B vik From the microtremor observation results, the average acceleration and the average velocity transmission ratio are calculated using Equation 13 and Equation 14. The values ​​before and after reinforcement are compared in Tables 30 and 31. These are for the i-th story of the structure. The ratio of the spatial average acceleration or velocity of the part supported by and the acceleration or velocity of the reference point Therefore, the value of the first floor is the average response magnification of the entire structure. i is the average acceleration Degree energy transfer rate B aik The values ​​of each floor are normalized by the values ​​of the first floor (see Equation 17). ).

[0212] [Table 30]

[0213] [Table 31]

[0214] This building is located on Class 2 ground, and the natural period of the ground is T c =0.6sec, building height h=14.3m, the height of the steel frame part is 2.95m, the height of the steel frame floor (excluding the basement) The ratio λ to h [m] is 0.206. Therefore, in the current standard formula (see formula 12), The natural period of the building is calculated as T = h(0.02 + 0.01λ) = 0.32 sec. T <T c Therefore, the vibration characteristic coefficient R t = 1.0, and the acceleration response magnification is the current standard It is concluded that the standard value at the time of establishment was 2.5 to 3.0.

[0215] Based on the above, let's look at the actual response magnification, which is the value for the first floor. The acceleration and speed are almost the same. In measurement 1, the values ​​were 2.5 to 4.0 before reinforcement, 2.0 to 3.7 after reinforcement, and In measurement 2, the absolute value was 2.0 to 2.4 before reinforcement and 1.6 to 2.2 after reinforcement. This is roughly equivalent to the current standard of 2.5 to 3.0. It shows.

[0216] Next, let us look at the rate of change before and after reinforcement. As shown in Table 31, Regarding the acceleration response magnification of the part, only the Y direction of measurement 2 after reinforcement increased slightly (7%). However, at other measurement points, the decrease is about 70% to 90% in each direction. Regarding the response ratio, there is a slight increase in the Y direction in measurement 2, but the others are decreasing. The figures quantify the changes that have been made to the structure so that it is less susceptible to earthquakes as a result of the reinforcement work. These values ​​are used to calculate the degree of damage, and are The above features are reflected in the values.

[0217] 5) Microtremor characteristics Table 32 shows the RMS of micro-tremor acceleration before and after reinforcement, and the energy transfer rate and the change before and after reinforcement. Table 52 shows the central period and bandwidth index of microtremor acceleration before and after reinforcement. Tables 34 to 37 show the characteristics of the micromotion speed and displacement. Dynamic acceleration is measured and velocity and displacement are cut off at 10Hz and 0.2Hz. After filtering, the data is integrated using the linear acceleration method. In each table, the floor indicates the floor It is the floor surface.

[0218] [Table 32]

[0219] [Table 33]

[0220] [Table 34]

[0221] [Table 35]

[0222] [Table 36]

[0223] [Table 37]

[0224] The energy transfer coefficient is calculated by dividing the RMS of the reference point defined in paragraph "0067" of this specification by the RMS of the reference point of each floor. It is the ratio of RMS, that is, the amplification factor of vibration, and is the basis for calculating each diagnostic index shown in the previous section. It has become.

[0225] The central period is expressed by Equation 1, and the bandwidth index is expressed by the method described in paragraph "0156" of this specification. The central period is the expected value of the zero crossing period for a stationary Gaussian process. where the bandwidth exponent is 1.0 for a sine wave and 0 for white noise. The acceleration approaches zero as the reinforcement progresses. As for the speed, the central period is slightly larger in measurement 1, and the The bandwidth index increases at both stations. Regarding the micro-tremor displacement, the central period is clearly reduced after reinforcement, The bandwidth is increased because the vibration becomes closer to a sine wave and the structure is This indicates that the stiffness of the system is improved.

[0226] Tables 38 to 40 show the central period measurement values ​​and the current standard primary fixed values ​​for micro-motion acceleration, velocity, and displacement. The calculated values ​​for a certain period are compared. Structures subjected to microtremors or earthquake motions are subject to irregular vibrations. As the frequency of the beam moves, the central period of the displacement, velocity, and acceleration increases with the bandwidth (see the (See paragraph "0156"). In this example, the value of the first natural period calculated using the formula in the current standard is There are central periods for acceleration, velocity, and displacement. Since the central period was almost the same for each point, each floor, and each direction, the entire building It is thought that the body vibrates in a specific mode.

[0227] [Table 38]

[0228] [Table 39]

[0229] [Table 40] EXAMPLES

[0230] 1) Target facilities and measurement methods The measurement subject is an 11-story SRC building completed in 1994 (2 spans in the X direction, 1 span in the Y direction). The first floor of the building is a pilotis apartment building with a parking lot (see Figure 24). However, in the X direction, There is a stairwell, etc. Between the end of August and September 2017, two independent columns (A2, A3) on the first floor were The wire was wrapped using the SRF method (see lines 1 to 3 of paragraph "0194" of this specification). The first 11th floors are residential units, and the second to tenth floors are earthquake-resistant walls. The measurements were carried out by installing two vertical arrays near the B2 and B3 columns on each floor, and Three instruments were placed on each floor near B1, A2 (see Figure 25), and B3 on the roof. The three-point planar observation was carried out on August 25, 2017, with four instruments installed before the reinforcement, and on August 25, 2017, with four instruments installed after the reinforcement. The test was carried out on December 19th with 12 vehicles. Note that access to the second floor near B2 was not permitted. Figure 26 The first floor plan shows the positions of the reinforced columns and the arrangement of the instruments.

[0231] 2) Measurement results Figure 27 shows the horizontal trajectories of the micro-motion displacement of the B3 vertical array after reinforcement for 6 minutes on each floor. The measurements are divided into three parts, each lasting two minutes. The signal increases from the first floor to the upper floors. It can be seen that each point moves in a circular motion.

[0232] Table 41 shows the energy transfer coefficients for the B2 vertical array and the rooftop, and Table 42 shows the energy transfer coefficients for the B3 vertical array. The ratio of microseismic displacement RMS of the first floor and that floor to each other is shown in Table 41. The columns shown are the energy transfer rates for rotation around the coordinate axes of the roof surface. After reinforcement, The X-axis circumference is reduced to about 1 / 10, and the Y-axis circumference is reduced to about 1 / 30. The column below RF in 2 shows the energy transfer rate of the translational motion and the ratio before and after reinforcement, but B2 and B3 Both of these are reduced significantly in the upper floors. The two independent columns (A2, A3), especially the lower floor wall-passing column A2, were wrapped around the structure, which stabilized the vibration mode. This represents a determined effect.

[0233] Figure 27 shows the movement of the roof surface before reinforcement, and Figure 28 shows the movement of the roof surface after reinforcement. Displacement data (XYZ three components) from the micromotion gauge is input into the structural analysis result visualization software AVS. This is a depiction of a moment in which something is visualized (animated) by using the power of the Before reinforcement, the roof surface was vibrating significantly up and down and left and right, but after reinforcement, it was almost horizontal. It can be seen that the vibration is in a circular motion within the plane. This is shown in Table 1.3.9.1 as the plane. The energy transfer rates around the X-axis and Y-axis decreased to 11% and 3%, respectively, before and after reinforcement. This clearly shows that

[0234] [Table 41]

[0235] [Table 42]

[0236] Tables 43 and 44 show the story shear force distribution coefficient (Ai) after reinforcement and the central period of microtremor displacement. The measured value of (Tc) and the calculated value of the primary natural period (T) according to the seismic code (paragraph "003" of this specification) The actual measurements of A1 are almost the same up to around the 5th floor. However, the amplification of earthquake motion on the upper floors was clearly smaller than the calculated value, i.e., the pilotis This indicates that this is a vibration mode specific to the structure. The central period varies slightly between the lower floors and the rooftop. However, on the upper floors, both B2 and B3 are almost constant and close to the calculated values.

[0237] [Table 43]

[0238] [Table 44]

[0239] Table 45 shows the story shear coefficient of the first story when the horizontal bearing capacity near B3 is reached (C ui 1km ) is the actual measured value (Equation 27). For the 2nd to 10th floors, the Y direction is smaller than the X direction. The large value reflects the fact that the partition walls between the 2nd and 10th floors on both sides of the building are earthquake-resistant. The fourth and fifth floors are lower than the other floors. During construction, heavy rains hit, construction was halted, and work resumed about a week later. Due to the heavy rain and interruption, the quality of the concrete deteriorated and the horizontal bearing capacity This is thought to have led to a decrease in strength.

[0240] [Table 45]

[0241] Tables 46 and 47 show the contents of paragraphs "0119" to "0172" of this specification and the corresponding The velocity conversion value of the expected value of hysteretic absorbed energy derived in the content (Vmik ) and damage level (I dik The characteristics of the input earthquake motion are as follows: strong earthquake duration time s0=7sec, maximum speed V max =0.8m / sect, maximum acceleration V max =4.0 m / sec 2 In addition, considering that the building is built to the new earthquake resistance standards, The toughness index F uik = 3.0. Note that the limit number of iterations is for the second floor and above. Considering that it is a steel reinforced concrete column, N ik = 15, and the first floor is SRF construction. From the experiment that confirmed the effect of the winding reinforcement method, ik =45.

[0242] Tables 46 and 47 show the input earthquake motions, which are values ​​representative of the recent earthquake environment, and are the strong earthquake succession. Duration s0=sec, Maximum speed V max =1.2m / sec, maximum acceleration A max =10 m / sec 2 (See Table 19.) The toughness index and the limit number of cycles are as described above. That was the case.

[0243] Looking at the calculation results of hysteretic absorbed energy in Table 46, the current standards assume that the earthquake motion is The result was that the Y direction was hardly absorbed (yield displacement was not reached). However, In the X direction, the 4th, 5th and top floors, where poor concrete construction is suspected, collapsed. The results are as follows. In addition, for the earthquake motions in Table 48 that represent recent earthquake environments, The results show that there is a large amount of absorbed energy, except for the intermediate floors in the nearby Y direction.

[0244] The damage levels in Tables 47 and 49 indicate whether the energy absorbed by each layer is within the damage limit. However, for earthquake motions assumed in the current standards, both B2 and B3 are in both the X and Y directions. In this sense, the current standard (new earthquake resistance standard) is below the limit value (1.0). However, on the 4th, 5th and top floors, where poor concrete construction is suspected, On the other hand, the results show that the earthquake motions shown in Table 49, which are representative of recent earthquake environments, are close to the limit. In the Y direction near B3, the temperature is within the limit except for the 4th and 5th floors, but there is a large difference in the X direction. This resulted in damage. The building has a pilotis structure, and there was a large earthquake on the first floor. It is calculated that hysteresis loop energy will be generated, but even so, the pillars wrapped with the SRF method The results for the first floor and the second floor directly above, which were reinforced with concrete, were almost within the limit. Regarding the upper floors, it is necessary to consider reducing damage by taking measures such as winding construction. The result is.

[0245] Although the above example is tentatively set, the limit number of cycles and toughness index of each component are set based on the same type of component. It can be determined from the load-displacement history and the degree of damage obtained from repeated loading tests. In addition, the maximum acceleration, velocity, displacement, and duration of the strong motion of the earthquake can be calculated by summarizing the earthquake motion observation results. can be decided jointly.

[0246] [Table 46]

[0247] [Table 47]

[0248] [Table 48]

[0249] [Table 49]

[0250] As described above, the damage level of the present invention is the degree of damage to a structure according to the level of earthquake motion. The effectiveness of countermeasures against this was evaluated by measuring the various transmission rates and limit repeatability of structures measured by microtremor observation. It can be quantitatively shown using the number of reversals and ductility index. It contributes to the rationalization of earthquake-resistant design. It is.

[0251] An example of application of the method of the present invention to a block wall will now be described.

[0252] 1. Installation FIG. 29 is a schematic diagram showing the layout relationship between the block wall, foundation, ground, and microtremor meter. The dynamic gauge 1 is placed on the top 17 of the block wall 16, on the foundation 18, or on the ground surface 20 near the foundation 18. When installing the micromotion meter 1 on the top 17 of the block wall 16, the foot 1 The point a is on the center line of the top 17 of the block wall 16. When installing on 1 or when the friction on the foundation 18 is large, use an iron plate.

[0253] 2. Measurement Simultaneous measurements are taken for about 6 minutes on the top 17 and foundation 18. The data is the same as that of the building diagnosis. Then, the free kick and micromotion diagnostic Excel are used to analyze. The height of the fence 16 (z coordinate of the microtremor 1 at the top 17 and the microtremor 1 at the base 18 or surrounding ground 21) The difference between these two is H, and the weight supported by the layer is zero. The calculations are velocity, displacement, RMS, central period, and transmissibility for each time history. The inter-story displacement or absolute displacement of the top is taken as the time history of interest d(t), and the base17 or surrounding The measurement point of the surrounding ground 21 (see No. 1 in Figure 29) is used as the reference point, and the transmission coefficient (h dk ) to calculate

[0254] 3. Diagnosis Displacement of the reference point x for a large earthquake assumed by the diagnostic criteria Gkmax When the distance is 2.5cm, The relative or absolute displacement of the top 23 is predicted using the formula below (yellow text, formula 1.4.8).

[0255]

number

[0256] In the above equation, d(t)=y2(t)-y1(t), h dk =RMS[d(t)] / RMS[y1(t)] predicts the relative displacement.

[0257] Also, d(t) = y2(t), h dk = RMS[d(t)] / RMS[y1(t)] Then, the absolute displacement is predicted.

[0258] Here, d(t), y2(t), and y1(t) are the relative displacements of the apex 23 and the reference point, respectively. position, absolute displacement of the top 23, and the y-direction (orthogonal direction to the block wall 22) component of the absolute displacement of the reference point. be.

[0259] The relative displacement between the top 16 and the base 17 during an earthquake, or the absolute value of the top 16, calculated using formula 50, is From the expected value of the displacement, the risk of collapse of the block wall 15 (I tbw ) to calculate

[0260] If the average value of the critical slope for tipping is D / H, the formula is as follows:

[0261]

number

[0262] where D [cm] is the width of the block wall 15 (see Figure 29), and E [d Gkmax ]teeth, The absolute displacement or deformation of the top 16 of the block wall 15 in the event of a large earthquake assumed in the seismic evaluation standard. is the expected value of the relative displacement, and a (see Table 50) is the overturning limit when the overturning limit slope is D / H. This is the apex displacement.

[0263] [Table 50] EXAMPLES

[0264] Next, a specific example of microtremor measurement in which the method of the present invention is applied to a block wall will be described below.

[0265] The specifications are as follows: Location: Block wall of an apartment building in Hirakata, Osaka Prefecture Structure: CB construction Thickness: 150mm Extension: ~15000[mm] Height: 1870 [mm] (The height from the reference measuring device to the top is 1790 [ mm] Block size: (thickness x extension x height) 150 [mm] x 390 [mm] x 200 [mm] Buttress: None Four micromotion measuring devices used

[0266] Figure 30(a) to (c) show the actual measurement conditions at each measurement point. (a) is the situation at measurement point 1, (b) is the situation at measurement point 2, and (c) is the situation at measurement point 3. Figure 31 shows the block wall seen from above, corresponding to Figure 30. FIG. 2 is an explanatory diagram showing a schematic arrangement of a measuring device (micromotion gauge).

[0267] The risk of block walls collapsing was calculated using formula 51. is shown in Table 51.

[0268] [Table 51]

[0269] According to Table 51, the fall risk is below 1.0 in all cases, which is within the range assumed by the seismic assessment standard. The risk of falling was not considered to be high due to the vibration (maximum displacement 2.5 cm). However, Earthquake motions greater than this (such as recent earthquakes) pose a risk of falling.

[0270] The role of micromotion diagnosis The method of assuming that the action of an earthquake is an inertial force proportional to the ground acceleration (inertial force approximation) is Regardless of the earthquake standard or whether dynamic or static calculation is used, this is the basic principle of current earthquake-resistant design. , along with the development of numerical calculation methods such as the finite element method and digital computers, From the late 1990s to the present, structures of a scale, shape, and materials never before seen on Earth have been constructed. This became the driving force behind the construction of new earthquake-resistant structures in earthquake-prone areas around the world, including Japan. The new earthquake resistance standards require that the collapse process of structures be tracked numerically, so dedicated software is required. Earthquake resistance calculations have become so complicated that structural design is impossible without them. Even experts do not know the structural earthquake resistance index or It is physically impossible to grasp the details of the horizontal bearing capacity or the calculation process of dynamic analysis. The reality is that we have no choice but to trust the figures that computers put out. Seismic activity has increased since then, with the magnitude and duration of observed earthquake motions increasing by 1970. This is several times to even an order of magnitude higher than the current standards, which were established based on earthquake observations up until the 2000s. .

[0271] The inertial force approximation does not hold for recent earthquake motion levels where ground acceleration exceeds 1G. The incompatibility of designing a structure-ground system that is intended to move in three dimensions separately in the x and y directions The rationality of this theory also becomes clear. First of all, the spatial and temporal scale of a large earthquake is different from the scale of individual structures. There is no comparison. If you try to capture the seismic motion of a large earthquake on the scale of a structure, it will be extremely random. The phenomenon that causes a large earthquake is one in which even a slight change in conditions can cause discontinuous and large results. This is called a statistical phenomenon. Based on calculations using the current standard method, Constructing a structure of a scale and type that has never existed before will be a challenge, even in terms of input earthquake motion. The computational assumptions and models are also not reasonable.

[0272] The 1891 Nobi earthquake prompted research into modern earthquake-resistant structures in Japan. Combined with the development and improvement of concrete material design and construction technology, the structure survived the Great Kanto Earthquake of 1923. By the 1960s, major cities including Tokyo had begun to see construction of heavy construction projects based on low- to mid-rise reinforced concrete buildings. However, the height restrictions were lifted in 1963, and the 1964 Tokyo Olympics The rapid spread of concrete pumping methods, along with the rapid economic growth policy, led to the Buildings are being demolished, and overcrowding and high-rise construction are progressing rapidly.

[0273] The area was hit by a seismic intensity of 7 during the 1995 Great Hanshin-Awaji Earthquake, and is more than three times the level expected under current standards. Even under the old standards, about half of low- to mid-rise RC buildings suffered no damage, except for the pilotis. Only a few percent of civil engineering structures, such as Shinkansen viaducts and expressways, have collapsed. The roads and other structures collapsed, but the earthquake motion was several times greater than the design assumption, and the foundation of the old river channel, etc. The damage was concentrated in the most affected areas, so it was said that it was only natural that the building would collapse. The same thing happened in the 2011 Great East Japan Earthquake. Even under the old standards, buildings collapsed due to earthquake motion. Only a few low-rise RC public buildings with Is values ​​of 0.3 or less suffered earthquakes of intensity 5 or more. Of the 98 buildings, none collapsed, and 97 were largely undamaged and still in use. School buildings and apartment buildings that had been reinforced to withstand earthquakes became unusable and were demolished or required major repairs. In addition, the Tohoku Shinkansen had already implemented earthquake-resistance reinforcement using steel plates on the bridge piers. After the earthquake, the line was closed due to the destruction of beams and damage to the overhead lines and other superstructure, and it took more than 50 days to restore service. is.

[0274] The aforementioned diagnostic criteria state that a fundamental revision of the current earthquake resistance standards is necessary. This article explains the characteristics of microtremor diagnosis and how it can be used to carry out rational seismic design, supervision, and reinforcement work. State the role you will play.

[0275] (1) Response calculation The performance required for structures during earthquakes is to minimize damage and to be able to continue using them. In recent earthquakes where ground acceleration exceeds 1G, indicators such as horizontal bearing capacity are It is not only physically difficult to use the nonlinearity detection method to track the structure after it becomes nonlinear, but also difficult to use. From the viewpoint of ensuring the continuity of use, it is necessary to have a structure that does not cause nonlinearity, i.e., a diagnostic criterion. As stated in the paper, buildings with high strength (high hurdles for nonlinearization) are desirable. What can be learned from response calculations is the structure's ability to withstand a specific earthquake motion or a general earthquake motion. Vibration mode, maximum acceleration, velocity, displacement, and hysteretic absorbed energy when the structure-soil system responds linearly Microtremor diagnosis can directly obtain the information required for calculations within the elastic range. It is also easy to compare calculations with actual measurements.

[0276] (2) Earthquake motion assumptions The action of an earthquake is a near-field action. It moves from the epicenter to the surrounding ground, and then from the surrounding ground to the foundation. The assumed earthquake motion (calculated) is based on the actual phenomenon of the earthquake traveling from the base to the first floor pillars. It is reasonable to determine the earthquake motion to be used for the construction, as the current building code does. The method of predetermining the response acceleration or response spectrum of a structure is not only unreasonable, but also There is a risk that excessive seismic force will be generated in structures, causing them to collapse or sustain major damage. In addition, we can numerically synthesize earthquake motions that match the response spectrum and perform time history response analysis. would be putting the cart before the horse.

[0277] The location where the expected earthquake motion is defined is the engineering bedrock surface, and the ultimate strength calculations, etc. However, the earthquake motion that a structure actually receives is that of the engineering bedrock directly below. In addition, the impact is caused by the wide area of ​​the basement that spreads three-dimensionally. It is almost impossible to perform three-dimensional vibration analysis of the ground. When calculating the original multiple reflection, the difference between the earthquake motion actually input to the structure and the calculated earthquake motion is The differences are bound to be extremely large.

[0278] In the microtremor diagnosis, input vibration is applied to the foundation of the structure. The maximum acceleration, maximum velocity, maximum displacement, and duration of the strong earthquake are used. Even if specific values ​​are determined for the magnitude of earthquake motion, they are still merely expected values ​​(average values) The actual earthquake motion will vary greatly from this value.

[0279] (3) Performance evaluation In recent earthquakes where the ground acceleration exceeds 1G and lasts for more than a few minutes, Visible displacements will inevitably occur in buildings from low rise to super high rise buildings, and many repeated displacements will occur. In addition, it is necessary to set indicators for each layer of the structure. It is necessary to evaluate performance using a collection of indicators related to individual components and parts, rather than simply aggregating them. There is a need. In microtremor diagnosis, the degree of damage is defined and used as an index to directly evaluate the continued use of the equipment. This is called the seismic absorption performance index.

[0280] (4) Rational earthquake-resistant structure Recent earthquake motion levels are not expected to cause total collapse of structures as assumed by the current standards. In this case, collapse is unavoidable according to calculations, and continued use is not possible. The structure is designed to move in such a way that the parts that absorb the energy of the earthquake motion and the parts that limit deformation to within the damage limit are planned in advance. The structure is rational. In regular RC structures, the head and base of each column act as bending hinges, limiting the overall deformation. In the case of eccentric buildings and pilotis, the capitals and bases of the columns in the areas with fewer walls move. The pilotis floor, the part that is eccentrically shaken, vibrates greatly and absorbs the energy, and other Deformation of floors and parts can be kept small. In RC structures, unless the structure is located on bedrock, the rigidity of the structural frame is sufficiently greater than that of the surrounding ground. Therefore, in addition to the vibration of the structure, the energy generated by the boundary (foundation) between the surrounding ground and the structure is also - It is necessary to consider the absorption of earthquakes in a planned manner. It is necessary to incorporate the relative movement of the foundation and the surrounding ground into the design. In wooden structures, the deformation and energy absorption capacity of each joint and nailing part is large. Therefore, joints and nailing parts should be designed to have three-dimensional mobility and resilience. We would like to specifically reflect in the design the reduction in earthquake effects caused by the platform rising up. Microtremor diagnosis is used to estimate the cumulative strength index and damage level of each part of a structure against the assumed earthquake motion of the current standards. By calculating and visualizing the natural vibration modes, the antinodes and nodes of vibration can be extracted and the main members and connections can be By reinforcing the joints to provide them with energy absorption capabilities, the movement ability to withstand a major earthquake is improved. The SRF method is effective for the above reinforcement. It is effective.

[0281] (5) New construction inspections and structural repair inspections After the construction of a structure is completed or after the renovation work is completed, a microtremor diagnosis is carried out to check the vibration mode. , vibration period (T m ), story shear force distribution coefficient (A im ), response ratio (R amk , R vmk ), cumulative strength index (C T S D ) m , damage degree (I dm ) and compare it with the design calculation. The validity of calculations and construction work will be confirmed, and the results will be used as a basis for deciding whether to add countermeasures, if necessary. The above indices can be calculated for the entire structure, and also for the individual sections. Vertical array measurements are also used to ascertain the vibration characteristics of that area. Currently, intermediate and confirmation inspections for new buildings are conducted by inspectors who visually check for consistency with drawings. The same is true for seismic retrofitting. It is possible to add objective numerical values ​​to the indicators.

[0282] (6) Periodic health checks When microtremor diagnosis is carried out periodically and the indicators in the previous section are measured, deterioration of the structure is found. After the repair, the microtremor diagnosis will be carried out again to confirm the effect of the repair. This can be used as a reference material.

[0283] (7) Seismic assessment and seismic retrofit design for existing structures Conduct microtremor diagnosis on existing structures built under current or previous earthquake resistance standards to assess their earthquake resistance. Performance will be evaluated, and if necessary, the results will be used to design and implement countermeasures. Measurements and diagnosis can be carried out and the data can be used to quantitatively confirm the reinforcement effect. Currently, earthquake resistance inspections are being carried out over a period of several months, at a cost of several million yen or even more than 10 million yen. This is because the calculations are complex and require a high level of expertise. If we simplify the process and make a judgment based on the indices obtained from microtremor diagnosis, it will cost more and take more time. can be significantly reduced.

[0284] (8) Analysis of Damaged and Non-Damaged Cases In the future, a large number of actual measurements will be accumulated and correlation analyses with actual damage and non-damage in actual earthquakes will be carried out. For example, the ratio of calculations and diagnostician's judgments can be minimized, and seismic diagnosis and repair locations can be determined based mainly on the results of microtremor diagnosis. It is expected that this will enable the design of renovations, such as the extraction of defects. This will increase the role of microtremor diagnostics in the field, making it possible to focus calculations and judgments on the necessary scope. .

[0285] The issues with earthquake resistance standards and solutions using the SRF method (bandage reinforcement) were reported in April 2017. He has published a paper entitled "Revolutionizing Earthquake Resistance" in 2013. We hope that this will help reduce the economic burden and risks associated with earthquakes.

[0286] As is clear from the above detailed description, according to the present invention, diagnosis of an existing structure is performed. - Cumulative strength index and expected structural seismic index used in seismic retrofit design, and current design of new buildings The expected value of the distribution coefficient of the story shear force in the height direction used in the analysis and the continuous use of the structure are directly evaluated. The damage level for evaluating the damage can be defined and its expected value can be obtained directly from the measured value of microtremors. By observing the vertical arrays installed in each part of the structure, the It is possible to measure the vibration characteristics, strength, damage level, etc., and as a result, it is possible to assess the soundness and safety of structures. Compared to the conventional method of directly applying external forces to structures, this method not only provides more detailed earthquake-resistant design and reinforcement, Earthquake resistance evaluation according to individual vibration characteristics, earthquake-resistant design and continued use of structures (including earthquake-resistant reinforcement work) This makes it possible to directly, cheaply, and quickly evaluate the performance of a vehicle (the most important target performance of a vehicle).

[0287] In other words, according to the present invention, by using the above indexes, after new construction, after renovation work, and after regular maintenance, This will enable seismic assessments to be performed at a much cheaper and faster rate than current seismic assessments. This will enable rational earthquake-resistant reinforcement design and earthquake-resistant design of new structures. [Explanation of symbols]

[0288] 1 Microtremometer 1a Foot 2 Analyzer 10 Structures 10a,10b,10c layer boundary surface 11 RC hospital building 12 1st floor 13 2nd floor 14 3rd floor 15 4th floor 16 Block Wall 17 Top 18 Basics 20 Ground surface 21 Surrounding ground

Claims

1. In a method for evaluating the performance of a structure through continuous microtremor observation, The microtremor time histories are simultaneously observed at multiple observation points within the structure, and the square of these time histories is calculated. Using the root mean square (RMS), calculate the estimated value A of the index used in the seismic design of the structure. Then, the ratio of this value A to the value B of the index used at the time of design corresponding to this value A is used to calculate the above structure. An evaluation of seismic performance of a structure based on the observation, The index is the acceleration response magnification R ａｍｋ and The estimated value A of the index used in the seismic design of the structure is the acceleration when reduced to a single degree of freedom system. Response magnification R ａｍｋ is the expected value of Acceleration response magnification R when reduced to a single degree of freedom system ａｍｋ The expected value of In Equation 13, [Equation 13] and Average acceleration transmission rate B when j = 1 ａｉｋ is the average absolute acceleration of the structure (column a in Table 7) Ratio of the absolute acceleration b of the reference point (see column b of Table 7) (however, [Table 7] Here, mj is the mass of the jth layer, a (see column a in Table 5), and b (see column b in Table 5) are the masses of the jth layer, are the energy transfer rates of acceleration and velocity in the k direction of the jth layer, respectively, and B ａｉｋ Average acceleration degree energy transfer rate, B ｖｉｋ is called the average velocity energy transfer rate. -Transmissibility is the ratio of the RMS of the microtremor time history of interest to the microtremor time history of the reference point, and is used for microtremor diagnosis. Now, assuming that this is preserved at the time of maximum elastic response due to earthquake motion input, the peak factor is set appropriately. Assuming that the maximum response of the target time history is calculated by multiplying the maximum input value at the reference point by the energy transfer rate. do. [Table 5] ） That is, A diagnostic evaluation method for structures based on their microtremors.

2. In a method for evaluating the performance of a structure through continuous microtremor observation, The microtremor time histories are simultaneously observed at multiple observation points within the structure, and the square of these time histories is calculated. Using the root mean square (RMS), calculate the estimated value A of the index used in the seismic design of the structure. Then, the ratio of this value A to the value B of the index used at the time of design corresponding to this value A is used to calculate the above structure. An evaluation of seismic performance of a structure based on the observation, The index is a product of a cumulative strength index and a shape index as defined in the current standard, The amount obtained by multiplying the ultimate cumulative strength index in the k direction of the i-th layer by the shape index ((C ＴＵ S Ｄ ) ｉｋ ) The expected value of [Equation 32] It is expressed as (where h ｅｇｉｋ is the correlation displacement energy transfer rate obtained by microtremor diagnosis, and the reference point Displacement x Ｇ０ [1978] is the reference point displacement corresponding to the standard earthquake motion (G0), and e Ｇ０ｉ ｋ is the correlation displacement, and e Ｙｉｋ is the yield displacement. ＴＵ is the cumulative strength at the end is an index, S Ｄ is the shape index, (C ＴＵ S Ｄ ) mik is the cumulative strength index at the end of the game. is the expected value of the product of the eigenvalues.) The estimated value A of the index is calculated by multiplying the final cumulative strength index in the k direction of the i-th layer by the shape index ((C ＴＵ S Ｄ ) ｉｋ ), which is the expectation of A diagnostic evaluation method for structures based on their microtremors.

3. In a method for evaluating the performance of a structure through continuous microtremor observation, The microtremor time histories are simultaneously observed at multiple observation points within the structure, and the square of these time histories is calculated. Using the root mean square (RMS), calculate the estimated value A of the index used in the seismic design of the structure. Then, the ratio of this value A to the value B of the index used at the time of design corresponding to this value A is used to calculate the above structure. An evaluation of seismic performance of a structure based on the observation, The index is a degree of damage, The degree of damage is [Equation 49] (Here, I ｄｉｋ is the damage level, B ａｉｋ is the circumference of the structure in the k direction of the i-th layer The average acceleration transmissibility of the part that supports the vibration characteristics obtained from microtremor observation of the ground system is B. ｖｉｋ is the average velocity energy transfer rate, T ｖｉｋ Microtremor observation of the ground around the structure The vibration characteristics obtained from the above are the average speed transmission ratio of the part that supports them, and a in Table 18 is the reference point is the inter-story displacement energy transfer rate in the k direction of the i-th story against the acceleration, T ｖｉｋ But the speed time is the central period of the calendar, and α ｖｉｋ is the bandwidth exponent, and s ０ is the duration of the strong earthquake, V ｍａｘｋ is the maximum speed, and A ｍａｘｋ is the maximum acceleration, and γ ｖ is the maximum speed peak is the peak factor, and γ ａ is the peak factor of the maximum acceleration. Ｙｉｋ is the yield deformation angle in the k direction of the i-th story, and H ０ｉｋ is the standard floor height, F ｕｉｋ is toughness is an index, N ｉｋ is the limit number of iterations. [Table 18] ） It is expressed as The estimated value A of the index is the damage level represented by the above formula 49. A diagnostic evaluation method for structures based on their microtremors.

4. In a method for evaluating the performance of a structure through continuous microtremor observation, The microtremor time histories are simultaneously observed at multiple observation points within the structure, and the square of these time histories is calculated. Using the root mean square (RMS), calculate the estimated value A of the index used in the seismic design of the structure. Then, the ratio of this value A to the value B of the index used at the time of design corresponding to this value A is used to calculate the above structure. An evaluation of seismic performance of a structure based on the observation, The index is a fall risk, The risk of falling is [Equation 51] (Here, I ｔｂｗ is the risk of falling, D [cm] is the width of the block wall, and E [d Ｇｋｍａｘ ] is the absolute displacement of the top of the block wall in the event of a large earthquake assumed in the seismic evaluation standard. is the expected value of the position or relative displacement, and a (see Table 50) is the tipping limit slope D / H. This is the tipping limit top displacement in this case. [Table 50] Furthermore, H is the height of the block wall, and h ｄｋ is the transmissibility. ） It is expressed as The estimated value A of the index is the fall risk expressed by the above formula 51. A diagnostic evaluation method for structures based on their microtremors.

5. The continuously measured microtremor time history is divided, and a plurality of partial time histories are extracted. The expected value of the index is calculated for the time history, and the sample average is used as the estimate of the index. The structure based on microtremors of a structure according to any one of claims 1 to 4. Diagnostic evaluation methods for artifacts.

6. The continuous micromotion measurement of a structure according to claim 5, wherein the duration of the partial time history is 1 to 2 minutes. A diagnostic evaluation method for structures based on the above.

7. The above observations are carried out after the construction of the structure, before and after renovation work, and during regular inspections. By comparing the estimated values ​​of the above points, the seismic performance of the structure and the risk of collapse in a major earthquake can be calculated. Diagnose and evaluate at least one of the changes over time in the continuity of use and the changes before and after the renovation work. The method for diagnosing and evaluating a structure based on microtremors of the structure according to any one of claims 1 to 4.

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