JP5092679B2 - Judgment method of building damage - Google Patents

Description

  The present invention relates to a method for determining the presence or absence of damage to a building, which evaluates the soundness and damage level of the building against an earthquake.

  Conventionally, several methods for determining the damage level of a building based on a signal obtained from an accelerometer installed in the building have been proposed. By processing the measurement signal, the natural period and attenuation constant are evaluated equivalently linearly, indicating the possibility of damage, estimating the interlayer deformation of the building, and determining whether there is damage from the relationship between this and the allowable deformation What is determined is a typical method.

  However, for example, in steel structures, past studies have revealed that the degree of damage to a member is not determined only from the maximum value experienced in the past, but is determined by energy damage that has been thrown in due to repeated deformation. However, in the conventional damage degree determination methods using observation records, there is no method for determining the damage degree of a building from this energy viewpoint.

  On the other hand, there is also a method of estimating the degree of damage to the building by analyzing the response in the same way as at the time of building design by using the earthquake record of the foundation instead of analyzing the measurement record as described above. However, there is usually a gap between the actual structure and the design specifications at the time of design, and it is necessary to study while changing the coefficients of the building model so that the observation records and the calculation results match. Requires a lot of effort and time, so it is not suitable for immediate judgment.

  In addition, there exist patent document 1, 2 as a prior art document relevant to this invention, for example.

  The invention of Patent Document 1 is a method for evaluating the seismic performance of a building that quickly and objectively determines the residual seismic performance of the building after the occurrence of an earthquake. The acceleration measured by the acceleration sensors installed on the foundation and upper floors of the building Calculate the absolute displacement at the measurement point by integrating the measured value twice, calculate the relative displacement and absolute acceleration of each floor of the building assuming the vibration mode shape of the building, and represent the response deformation amount of the building from those values The representative acceleration representing the representative displacement and the response acceleration of the building is calculated to obtain the performance curve of the building. On the other hand, the acceleration response spectrum and the displacement response spectrum are calculated as the input seismic motion that inputs the acceleration measurement value at the foundation. Thus, the required curve of the building is obtained, and the residual seismic performance of the building is judged from a comparison between the performance curve and the required curve.

  The invention of Patent Document 2 is an earthquake damage level determination system for an earthquake that objectively and efficiently predicts whether or not a bridge can be used after an earthquake. The acceleration sensor installed on the pier head of the bridge structure An acceleration response record is acquired, the change of the natural period before and after the earthquake is calculated, and the presence or absence of damage to the bridge is determined from the result of the calculation.

JP 2003-344213 A JP 2006-170661 A

  As described above, the damage degree determination method using the observation record does not determine the damage degree of the building from the viewpoint of energy, and there is a problem that the damage degree cannot be accurately determined.

  In addition, the estimation method that performs response analysis using the earthquake records of the foundation as in the case of building design has a problem that it is not suitable for immediate judgment because it requires a great deal of labor and time.

  The present invention has been made to solve the above-described problems, and while using the specifications of the building model, the amount of energy input to the building is calculated using the response waveform observed at the time of the earthquake. The present invention provides a method for determining whether or not a building has been damaged, which can be stably estimated and can accurately determine whether or not a building has been damaged in a short time.

According to the first aspect of the present invention, each mode is recorded using a waveform record of one or several points in the building foundation and the building at the time of an earthquake, and separately obtained building mass, natural period and natural mode shape. The input energy amount _s L (t) input to each building and the attenuation consumption energy amount _s D (t) due to attenuation are estimated, and the input energy amount _s L (t) and the attenuation energy consumption amount _{s at} each time are estimated. The maximum value of the absorbed energy W (t) of the entire building obtained by summing the building absorbed energy amount _s W (t) for each mode absorbed by the building, which is the difference of D (t) , up to the main mode order. If it is sufficiently smaller than the elastic allowable energy amount of the building, it is determined that the building is not damaged by the earthquake, and it is determined whether the building is damaged or not.

The invention of claim 2 of the present invention is the plasticity of each mode at the final time t _{m when} the vibration after the earthquake is sufficiently converged with respect to the building absorbed energy amount _s W (t) for each mode obtained in claim 1. Absorbed energy _s W (t _m ) is distributed to each layer i in proportion to the vibration energy distribution at the time of elasticity, and is added to each layer in proportion to the separately obtained building eigenmode and information on the strength distribution of each layer was a temporary plastic absorbed energy W _i of each layer i, the relationship between the shear force required layers to store plastic absorbed energy W _i of the temporary elastically, each layer i of plastic absorbed energy W _i of the temporary This is a method for determining the presence or absence of damage to a building, characterized in that the distribution of energy is corrected and the amount of plastic absorbed energy W _pi of each layer is calculated.

  The present invention is a method for simply evaluating the energy damage of a building based on the response waveform observed in the building during an earthquake. The energy balance of each mode is evaluated from a record of one to several points to determine the damage distribution law. By applying, the amount of plastic absorption energy of each layer is estimated. Information necessary for evaluation of residual seismic resistance after an earthquake or determination of a layer to be subjected to detailed investigation can be easily obtained.

  According to the first aspect of the present invention, the amount of energy input to the building is estimated using the specifications of the building model and using the response waveform observed in the building during the earthquake. Although the specifications of the building model are used, stable and good estimation is possible because small amounts of error such as mass, mode shape, and approximate natural period are used.

  The invention of claim 2 requires building strength information. However, since only the relative strength ratio of each layer is used, even if it is difficult to estimate the true value of member strength as in an old building, It can be estimated from only the relationship. In addition, since calculations can be performed in a very short time, not only can the results of detailed response analysis (forward analysis) using the earthquake records of the foundation be supplemented, but also the layers that require detailed investigation after the earthquake can be quickly identified. There are various usage methods.

Specifically, after the earthquake, the observation record is first corrected to the ground acceleration d ² y / da ² and the relative velocity dx / da, and then dx / da is decomposed into the respective secondary components _s v. Mode decomposition can be applied if there are multiple observation points.

  U is a mode matrix in which the stimulation coefficients at the observation position are arranged up to the order corresponding to the number of observation points, and a mode matrix obtained from building design specifications may be used, or a matrix obtained separately from observation records may be used. Good. When evaluating up to higher order than the number of observation points, or when the number of observation points is one, correction by a band pass filter + stimulus coefficient is performed to obtain each next velocity waveform. Even when using a bandpass filter, an approximate natural period of each mode is required, but this may also be a value obtained from building design specifications, or may be obtained separately from observation records.

Next, each subsequent energy response is determined. First, each next input energy _s L (t) and attenuation consumption energy _s D (t) are calculated by the following equations. Here, _s M is the s-order effective mass, t is the elapsed time from the start of the earthquake, and _s M may be calculated using the mass distribution and stiffness distribution of the building specifications.

The coefficient _s C in the equation (3) can be determined by the condition of _s D = _s L from the record at the time of a small earthquake that the building is sufficiently in the elastic range. The following equation, which is the difference between equations (2) and (3) at each time, represents the building absorbed energy in each mode at time t.

  The absorbed energy of the entire building can be obtained by summing up the equation (4) up to the main mode order.

While the building is shaking, that is earthquake continued in the equation (4) represents the sum of the elastic vibration energy and plastic absorbing the energy of the building absorbed energy that is, each mode of each mode, elastic vibration energy and plastic Although it is difficult to distinguish the absorbed energy , if the maximum value of equation (5) is sufficiently small compared to the elastic allowable energy of the building, it can be immediately determined that the building is not damaged by the earthquake. . The above is the invention of claim 1.

_Assuming that the vibration has sufficiently converged at time t _m after the end of the earthquake, the value _s W (t _m ) in equation (4) at this final time represents the plastic absorption energy _s W _p of each mode. Assuming that this _s W _p is an eigenvalue determined by the earthquake and building dimensions that is not affected by the position and concentration of the plasticized layer, the energy damage of each layer is equal, so-called optimal yield shear force distribution,
_s W _p is distributed to the i layer in proportion to the vibration energy distribution at the time of elasticity.

The distribution coefficient _s λ _i is determined in advance by the building eigenmode.

The shear force required to store W _i elastically can be written as Q _i = (2k _i W _i ) ^1/2 using the layer stiffness k _i . If the expression is similar to the modal analysis without using the layer rigidity,

When the equation (9) is regarded as the optimum yield shear force distribution for the observed earthquake and the damage distribution law is applied, the plastic absorbed energy amount W _{pi of} each layer is predicted as follows.

  As can be seen from the equation (10), the parameter for distributing the damage energy to each layer is a relative relationship of proof stress and not an absolute value. Therefore, even when the material strength is unknown as in an old building, it is a feature that it is only necessary to obtain a relative strength distribution from the relationship of the cross-sectional dimensions of the members.

  Since the present invention is configured as described above, the following effects can be obtained.

  (1) The amount of energy input to the building can be estimated stably and satisfactorily, and the presence or absence of damage to the building can be accurately determined in a short time.

  (2) The plastic absorption energy of each layer of the building can be estimated well, and the information necessary for the evaluation of residual earthquake resistance and the determination of the layer to be investigated in detail after the earthquake can be easily obtained.

  Hereinafter, the present invention will be described based on the illustrated embodiments. The present invention is a method for determining whether or not a building is damaged based on a response waveform observed in the building during an earthquake, and simply evaluating the energy damage of the building.

Observation information and the building information required, (a) the basis for the acceleration, the building to several points acceleration (velocity), (b) building the mass distribution m _i, 1 to several primary stimulation function .beta.u, vibration frequency omega, It is elastic limit proof stress distribution _QYi (relative distribution) of each layer, and an evaluation flow is shown in FIG.

  By a numerical analysis using a simple model, the determination method of the present invention was implemented as follows.

(1) Building model and input ground motion As shown in Fig. 2, two types of shear type multi-mass point models (A: 10 mass points, B: 15 mass points) were used. FIG. 2 shows the natural period and the stimulation function. As shown in Fig. 3, three types of input seismic motion were adopted and all were standardized to 75 cm / s. In FIG. 3, a 2V _E (energy) spectrum is shown. As building attenuation, 2% Layleigh attenuation is considered for each of the first and second order.

(2) Observation position As shown in Fig. 2, in addition to the basic acceleration, (A) all layers (reference), (B) top and middle two locations, (c) only top, (D) only middle It was assumed that the velocity waveform of 4 cases could be observed.

(3) Analysis results Shown for two waves with different response trends for each model. FIG. 4 shows the relationship between the skeleton and the maximum response value, and FIG. 5 shows the estimated plastic absorbed energy _s W _p of each mode. The error between the total amount of _s W _p evaluated in (A) and the response analysis result (correct answer) is less than 1%. The estimated values of (B) and (D) are almost the same as those of (A), and it seems that _s W _p can be estimated with high accuracy in the second order with the number of observation points of 1-2. However, (c) shows a smaller value than the others, and in the case of observation at one place, selection of the position is important.

FIG. 6 shows the plastic absorption energy distribution W _pi and also shows the estimation result (the damage concentration index is n = 6) by the equation (10). Even in the same building model, the location of the damage concentrated layer varies greatly depending on the seismic wave, but the estimated value and the correct value correspond roughly well. Although the value of (c) is also small, the distribution form corresponds, and the position of the layer where damage is concentrated can be estimated well in any case.

  Obtain the optimum yield shear force from the energy balance evaluated by analyzing the elastic-plastic response by elastic mode shape, and apply the damage distribution law to improve the plastic absorption energy distribution of the building from the observation records of about 1 to 2 points. Can be estimated.

  Information necessary for evaluation of residual seismic resistance and determination of layers to be investigated in detail after an earthquake can be easily obtained. In this method, it is important to evaluate the energy balance using the observed waveform, and it can be used to verify the accuracy of response analysis (forward analysis) using the building model and ground motion acceleration.

It is a flowchart of the determination method of the presence or absence of the damage of the building of this invention. It is a graph which shows the stimulation function of a vibration model. It is a graph which shows 22V _E (energy) spectrum of input earthquake motion. It is a graph which shows a skeleton and a response maximum value. Was estimated is a graph showing the plastic absorption energy _s W _p of each mode. It is a graph which shows the estimated plastic absorption energy distribution _Wpi .

Explanation of symbols

_s L: Input energy in each mode
_s D …… Attenuation energy consumption in each mode
_s W _p …… Plastic absorption energy of each mode W _pi …… Plastic absorption energy of each layer

Claims (2)

The amount of input energy input to the building for each mode using the waveform record of one or several points in the building foundation and the building at the time of the earthquake, and the separately determined building mass, natural period and natural mode shape _s L (t) and attenuation energy consumption _s D (t) due to attenuation are estimated,
The amount of building absorbed energy for each mode absorbed by the building, which is the difference between the input energy amount _s L (t) and the attenuated energy consumption amount _s D (t) at each time

Energy absorption of the entire building obtained by summing up to the main mode order

If the maximum value is sufficiently smaller than the elastic allowable energy amount of the building, the building is not damaged by the earthquake, and the presence or absence of damage to the building is determined. Building absorption energy amount for each mode obtained in claim 1

, The plastic absorption energy _s W (t _m ) of each mode at the final time t _{m when} the vibration after the earthquake has sufficiently converged is obtained from the information on the building eigenmode and the yield strength distribution of each layer separately obtained . the combined sum for each layer was partitioned layers i in proportion to the vibration energy distribution as a temporary plastic absorbed energy W _i of each layer i, needed to store the plastic absorbed energy W _i of the temporary resiliently Determining whether a building is damaged or not by correcting the distribution of the temporary plastic absorbed energy W _i to each layer i from the relationship with the shear force of each layer and calculating the amount of plastic absorbed energy W _pi of each layer Method.

Images