JP2005156448A - Dynamic earthquake-proofness performance of building, and evaluation method of the earthquake-proofness performance after earthquake-proofness reinforcement - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To quantitatively display the earthquake-proofness performance of a building and the effects of earthquake-proofness enforcement, by comparative examination of vibration characteristics, before and after repairing. <P>SOLUTION: Vibration characteristics of a building are calculated, using simultaneous measurement data of the ground and building under minute vibrations, at all times, and the building is diagnosed for earthquake-proofness, based on the vibration characteristics of the building. After upgrading for earthquake-proofness in accordance with this, the earthquake-proofness performance and the effects of earthquake-proofness reinforcement of the building are displayed quantitatively, by comparative examination of vibration characteristics, before and after the upgrading. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention calculates the vibration characteristics of a building using the simultaneous measurement data of microtremors of the ground and the building, performs a seismic diagnosis of the building based on the vibration characteristics of the building, and performs the seismic retrofit according to the diagnosis The present invention relates to a dynamic seismic performance of a building and a method for evaluating seismic performance after the seismic reinforcement in which the seismic performance of the building and the effect of seismic reinforcement are quantitatively displayed by comparative examination of vibration characteristics before and after the renovation.

  Conventionally, there are methods shown in Patent Document 1 and Patent Document 2 as methods for evaluating the dynamic seismic performance of buildings.

  Patent document 1 is an evaluation method and apparatus for dynamic earthquake resistance of a building based on data obtained by actually measuring an actual building structure and ground condition. Four types of seismic intensity C, dynamic toughness strength F, and dynamic seismic deterioration Is are evaluated.

  Patent Document 2 analyzes the vibration data obtained by measuring the fine movement of the building, calculates the weight and fine movement rigidity of the building based on the building information and the wall element information on the fine movement rigidity of the wall element of the building. Estimate the natural frequency of the building from the weight and microtremor stiffness, and compare the natural frequency calculated based on the vibration data with the natural frequency estimated based on the building information and wall element information. It is intended to diagnose sex.

JP 2003-042992 A JP 2003-041781 A

  In the method of Patent Document 1, the dynamic seismic soundness degree H is obtained as H = Ke · x / (W · CO · τPH), but Ke, x, W, and CO use existing numerical values. , ΤPH can be calculated by using a measured value, but it is not clear whether H composed of a mixture of the estimated value and the actually measured value can be used as the dynamic soundness.

  In addition, the dynamic seismic intensity C is defined as C = Ke · x / (W · τDH). Similarly, Ke, x, and W are obtained from the design books, and τDH is a measured value. As can be seen, the validity of using C as the dynamic limit seismic intensity for seismic diagnosis is not clear. Further, the dynamic toughness strength F is also a reciprocal of H, but it is difficult to understand the dynamic toughness strength.

  Moreover, in patent document 2, although the effect determination of seismic retrofit is performed by calculating | requiring a natural frequency (reciprocal number of a natural period), the calculation method is common and it is inadequate in accuracy. Conceivable. In addition, it is difficult to understand the correctness of estimating the natural frequency from the building weight and fine motion stiffness and diagnosing earthquake resistance from the comparison of both frequencies.

The present invention further improves such a conventional one, and makes it possible to diagnose earthquake resistance by directly measuring and determining the vibration period which is the property of a building.
According to the first aspect of the present invention, the vibration characteristics of the building are calculated using the simultaneous measurement data of the microtremors of the ground and the building, the building is subjected to the earthquake resistance diagnosis based on the vibration characteristics of the building, and the earthquake resistance repair is performed accordingly. After that, the seismic performance of the building and the effect of seismic reinforcement were quantitatively displayed by comparing the vibration characteristics before and after the renovation.

  The invention described in claim 2 is characterized in that the microtremors of the ground and the building are measured in the north-south direction and the east-west direction on the ground and a predetermined floor of the building.

Ｈ（ｆ）はインパルス応答ｈ（ｔ）のフーリエ変換
ｈ（ｔ）は建物に地盤から加えられる力ｘ（ｔ）と、それによって生じ
る建物の運動ｙ（ｔ）との間の系のインパルス応答である。

The invention according to claim 3 is characterized in that the vibration characteristic of the building is obtained by the following equation.

H (f) is the Fourier transform of the impulse response h (t)
h (t) is the force x (t) applied from the ground to the building and the resulting
The impulse response of the system between the building motion y (t).

ここで、Ｄｓは建物の構造特性係数 According to the fourth aspect of the present invention, a vibration measurement point is determined for each room of the building, and the natural frequency (f), amplitude magnification (R), natural period of the building is determined from the vibration magnification indicating the frequency response with reference to the ground ground motion. (T) and the Q value representing the degree of resonance sharpness are obtained, and the seismic performance index C (C ₁ , C ₂ ) is obtained by the following equation.

Where Ds is the structural characteristic coefficient of the building

  The invention of claim 5 is characterized in that when the seismic performance index (C) is equal to or greater than a predetermined value from the vibration measurement result, it is determined that the seismic performance should be implemented as a caution. To do.

  According to the invention described in claim 6, after the seismic retrofit, the vibration measurement is performed at the same place, and the amplitude spectrum and the natural period are compared, and if each room is within the predetermined value, it is judged that the seismic retrofit is acceptable. It is characterized by.

  As described above, according to the first aspect of the present invention, the vibration characteristics of a building are calculated using simultaneous measurement data of microtremors of the ground and the building, and based on the vibration characteristics of the building. After performing seismic diagnosis of the building and performing seismic retrofit according to it, the seismic performance of the building and the effect of seismic reinforcement were quantitatively displayed by comparing the vibration characteristics before and after the renovation. Since a certain vibration period can be directly measured, the evaluation of the seismic performance of the building and the effect of the seismic reinforcement of the building can be displayed quantitatively.

  According to the invention described in claim 2 of the present invention, the constant tremor of the ground and the building is measured in the north-south direction and the east-west direction on the ground and on the predetermined floor of the building. The characteristics can be grasped more accurately.

Ｈ（ｆ）はインパルス応答ｈ（ｔ）のフーリエ変換
ｈ（ｔ）は建物に地盤から加えられる力ｘ（ｔ）と、それによって生じ
る建物の運動ｙ（ｔ）との間の系のインパルス応答である。

により求めるようにしたので、建物の振動的な特性がすべてＨ（ｆ）に入ってきており、建物の振動特性を効果的に求めることができる。 According to the invention described in claim 3 of the present invention, the vibration characteristics of the building are expressed by the following equations (1) and (2).

H (f) is the Fourier transform of the impulse response h (t)
h (t) is the force x (t) applied from the ground to the building and the resulting
The impulse response of the system between the building motion y (t).

Since all the vibration characteristics of the building are in H (f), the vibration characteristics of the building can be effectively obtained.

ここで、Ｄｓは建物の構造特性係数
で求めるようにしたので、建物の耐震評価を実情に即した形式として評価することができる。 According to the invention described in claim 4 of the present invention, the vibration measurement point is set in each room of the building, and the natural frequency (f) of the building and the amplitude magnification are obtained from the vibration magnification indicating the frequency response with reference to the ground input ground motion. (R), Q value representing the natural period (T) and the degree of resonance sharpness is obtained, and the seismic performance index C (C ₁ , C ₂ ) is expressed by the following equation:

Here, since Ds is calculated | required with the structural characteristic coefficient of the building, it can evaluate the earthquake-proof evaluation of a building as a form according to the actual condition.

  According to the invention described in claim 5 of the present invention, if the seismic performance index (C) is greater than or equal to a predetermined value from the vibration measurement result, it is determined that the seismic performance should be subjected to seismic retrofit as a caution. As a result, it is possible to grasp the standards for seismic retrofit more specifically.

  According to the invention described in claim 6 of the present invention, after the seismic retrofit, the vibration measurement is performed at the same place, the amplitude spectrum and the natural period are compared, and if each room is within the predetermined value, the seismic retrofit is acceptable. Because it was decided, it is very useful as an earthquake countermeasure because it can create a concrete standard for seismic retrofit.

The dynamic seismic performance of the building according to the present embodiment and the seismic performance evaluation method after seismic reinforcement will be described with reference to the drawings.
In the dynamic seismic performance of the building and the seismic performance evaluation method after seismic reinforcement according to the present embodiment, the vibration characteristics of the building are calculated using simultaneous measurement data of ground and building microtremors. The seismic diagnosis of the building is performed on the basis of it, and the seismic renovation is performed accordingly, and the seismic performance of the building and the effect of seismic reinforcement are quantitatively displayed by comparing the vibration characteristics before and after the renovation.

  The microtremors of the ground and building are measured in the north-south direction and east-west direction on the ground and on the predetermined floor of the building.

Ｈ（ｆ）はインパルス応答ｈ（ｔ）のフーリエ変換
ｈ（ｔ）は建物に地盤から加えられる力ｘ（ｔ）と、それによって生じ
る建物の運動ｙ（ｔ）との間の系のインパルス応答である。

The vibration characteristics of a building are obtained by the following formulas (1) and (2).

H (f) is the Fourier transform of the impulse response h (t)
h (t) is the force x (t) applied from the ground to the building and the resulting
The impulse response of the system between the building motion y (t).

ここで、Ｄｓは建物の構造特性係数であり、変形能力による地震エネルギー吸収性能に応じた低減係数である。Ｄｓは構造種別（ＲＣ，ＳＲＣ，Ｓ造）により異なるが、柱、梁、壁の部材種別と耐震壁・ブレースのせん断力の負担比率により決定され、変形能力が大きいほど構造特性係数は小さくなる。 A vibration measurement point is set for each room of the building, and the natural frequency (f), amplitude magnification (R), natural period (T) and resonance sharpness of the building are determined from the vibration magnification showing the frequency response with reference to the ground ground motion. The Q value representing the degree is obtained, and the seismic performance index C (C ₁ , C ₂ ) is obtained by the equations (3) and (4). R and Q are theoretically the same, but since Q may not always be obtained, averaging is performed using both Q and R. Conventionally, C = TQR was used. However, since the unit is seconds, QR is averaged and used. The reason why T is divided by 0.1 is that there is nothing smaller than the natural period of 0.1. As described above, in the present invention, the seismic performance index is obtained from the amplitude factor (R), the natural period (T), which are actual measurement values, and the Q value representing the degree of resonance sharpness. It is known that the damage rate during an earthquake increases rapidly as the thickness of the alluvium increases, and the thickness of the alluvium is known from the prevailing cycle of the ground, and the predominance of buildings built on the ground It is based on the fact that the properties of the building, that is, the earthquake resistance, can be understood by measuring the period.

Here, Ds is a structural characteristic coefficient of the building, and is a reduction coefficient corresponding to the seismic energy absorption performance due to the deformability. Ds varies depending on the structure type (RC, SRC, S structure), but is determined by the column, beam, and wall member types and the shear ratio of the shear wall and brace. The larger the deformation capacity, the smaller the structural characteristic coefficient. .

  If the seismic performance index (C) is greater than or equal to a predetermined value from the vibration measurement results, it is determined that seismic retrofitting should be implemented with caution regarding seismic performance. As will be described later, there is no problem if C is 20 or less, repair is preferable for 30 or more buildings, and repair is essential if 40 or more. This standard is determined as follows. At the time of the Great Hanshin Earthquake, two-by-four houses with a C of 20 or less are not damaged at all. Moreover, since there are many things where damage has arisen in the house where C is 40 or more, if 40 or more, the standard is that repair is essential.

  After the seismic retrofit, vibration measurement is performed at the same place, and the amplitude spectrum and natural period are compared. If each room is within the specified value, it is judged that the seismic retrofit is acceptable.

FIG. 1 shows an apparatus for carrying out the seismic performance evaluation method of the present embodiment.
This apparatus is composed of a conductive speedometer 1 (GE-1 HS-1 LT), a dedicated 8ch amplifying means 2 and a control analysis program for seismic diagnosis of a wooden structure incorporated in a personal computer 3. The amplification means 2 also has an A / D conversion function. The personal computer also includes an I / F card for data from the amplification means 2. Further, an AC 100V power supply unit 4 for supplying power to the amplification means 2 is provided. Simultaneous measurement data of microtremors of the ground and the building can be obtained by installing up to 8 conductive type speedometers 1 on the building and ground, amplifying means 2 after amplifying the vibration, and A / D converting it as digital data. Analyze microtremor data with a computer.

  By using the method of the present invention, the vibration characteristics of a building are calculated for an actual building using simultaneous measurement data of ground and building microtremors, and the building is subjected to seismic diagnosis based on the vibration characteristics of the building. The seismic retrofit was performed in accordance with the results, and the seismic performance of the building and the effect of seismic reinforcement were quantitatively displayed by comparing the vibration characteristics before and after the retrofit.

  The target building is a 2-story wooden house (central part) that is expanded and renovated with a steel structure (west part) and used as a commercial building. FIG. 2 shows a floor plan of the second floor of this building and seven vibration measurement points from point A to point G.

Floor area of the first floor is about 270 meters ^2, there are 4 rooms, less partition wall because it is used for the work, apparently it seems structurally wall stiffness is insufficient. In order to measure the input vibration from the ground, a measuring point S was provided between the grounds of the first floor entrance hall.

As measurement equipment, vibration data is recorded using 8 exciters with a natural period of 1 second, amplifiers and recorders, and the obtained data is selected with a spectrum analyzer by selecting the part where the waveform is stable. Analyzed. FIG. 3 shows the amplitude spectra of the ground S point and the technical room A point, with the north-south direction (NS) and east-west direction (EW) components combined. At point A, an amplitude component due to significant resonance of 3-6 Hz is observed in the north-south vibration.
Further, FIG. 4 shows an amplitude magnification curve of the technical room A point representing the frequency response based on the input ground motion of the ground S point.

  From such an analysis result, the natural frequency (f), attenuation constant (h), and amplitude magnification (R) of this building are obtained. However, here, the natural period (T) and the Q value representing the sharpness of the resonance degree are used for convenience instead of the natural frequency and attenuation constant.

ここで、Ｄｓは建物の構造特性係数

この場合、固有周期Ｔ、共振度合Ｑ値、及び振幅倍率Ｒは相乗的に建物の耐震性能に関与するものと考える。しかし、こららは、いずれも大きいほど悪い効果が生じる、生み出すものと考えている。ただし、ＱとＲは、理論的には同等のものであることが分かっているが、実際に測定するときには、異なる場合が多いことから平均操作を加えて用いている。 Here, in order to evaluate the earthquake resistance of a building using the measured numerical value representing the dynamic characteristics of the building, the seismic performance index (C) should be defined and used as the following equations (3) and (4) To.

Where Ds is the structural characteristic coefficient of the building

In this case, the natural period T, the resonance degree Q value, and the amplitude magnification R are considered to be synergistically related to the seismic performance of the building. However, they all think that the bigger the result, the worse the effect will be. However, Q and R are theoretically equivalent to each other, but when actually measured, there are many cases where they are different from each other.

  FIG. 7 shows the relationship between the measurement points A to G of the seismic performance index (C) of this building. Looking at this, the technical room A point in the southeastern part of the building is as large as 64, and the vicinity of the warehouse G point in the northwestern part is as small as 37.

  Here, when the calculated seismic performance index (C) is judged in light of the results of the damage survey of the Hyogoken-Nanbu Earthquake, etc., if it exceeds approximately 30, it is considered that the seismic performance of the building needs attention.

As can be seen from the vibration measurement results, the target building was judged to have insufficient seismic performance in the southeast part including the Technical Office A point, and was subjected to seismic retrofit under the design of a professional architect. The actual construction was as follows.
A) New structural columns B) New structural walls (columns, beams, braces)
C) New construction wall (posts and braces)
D) New structural walls (posts / braces), structural plywood tension E) New structural pillars, three, additional structural plywood tension F) New structural walls (posts / braces)

  After the seismic reinforcement work on the building, the same vibration measurement as that described above was performed with the same equipment at the same location. FIG. 5 shows the amplitude spectrum of the technical room A after reinforcement together with the spectrum of the ground S point. In FIG. 5, the reinforcing effect is significantly shown as a reduction in vibration compared to FIG. 4.

  Next, changes in each measurement point of the natural period of the building before and after the seismic retrofit are shown in FIG. As can be seen, the natural period of vibration in the north-south direction has decreased as a whole from about 0.28 seconds to about 0.21 seconds, indicating that the rigidity of the first floor portion of the building has increased. According to Fig. 7, there are many rooms exceeding 30 after the renovation, but this is not a living space, it is a house with a complex structure consisting of reinforcing bars, lightweight reinforcing bars and wooden structures, and this is due to the balance with the budget. The renovation is considered reasonable. For reference, Fig. 8 shows the actual results of the seismic performance index of houses by various methods, and the results of this measurement. A comparative display is shown.

  In this way, using the simultaneous measurement data of microtremors of the ground and the building, the vibration characteristics of the building are grasped, and the earthquake resistance of the building is implemented based on such information, and the vibration characteristics before and after the repair are compared. By studying, it was shown that the evaluation of the seismic performance of buildings and the effect of seismic reinforcement of buildings can be displayed quantitatively.

It is a block diagram of the apparatus for enforcing the seismic performance evaluation method of embodiment of this invention. It is a top view explaining the floor plan and vibration measurement point of the second floor portion of the present embodiment. It is the graph which combined the north-south direction and the east-west direction component, and showed the amplitude spectrum of the ground S point and the engineering room A point. It is the graph which showed the amplitude magnification curve of the technical room A point showing the frequency response on the basis of the input ground motion of the ground S point. It is the figure which showed the amplitude spectrum of the technical room A point and the ground S point after reinforcement. It is the graph which showed the change of each measuring point of the natural period of the building before and after earthquake-proof repair. It is a graph which shows the relationship of each measurement point of AG of a building's seismic performance index (C). It is the graph which compared and displayed the example of the earthquake-resistant performance index of the house by various construction methods, and this measurement result.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Conductive type speedometer 2 Amplifying means 3 Personal computer 4 Power supply unit

Claims (6)

  Calculate the vibration characteristics of the building using simultaneous measurement data of microtremors of the ground and the building, and make a seismic diagnosis of the building based on the vibration characteristics of the building. A method for evaluating dynamic seismic performance of buildings and seismic performance after seismic reinforcement, characterized by quantitatively displaying the seismic performance of buildings and the effect of seismic retrofit by comparative examination of vibration characteristics.   2. Dynamic seismic performance of a building according to claim 1 and seismic resistance after seismic reinforcement, wherein the microtremors of the ground and the building are measured in the north-south direction and the east-west direction on the ground and a predetermined floor of the building. Performance evaluation method. 2. The method according to claim 1, wherein the vibration characteristic of the building is obtained by the following equation.

H (f) is the Fourier transform of the impulse response h (t)
h (t) is the force x (t) applied from the ground to the building and the resulting
The impulse response of the system between the building motion y (t).

A vibration measurement point is set for each room of the building, and the natural frequency (f ₀ ), amplitude magnification (R), natural period (T ₀ ), and resonance frequency of the building are determined from the vibration magnification indicating the frequency response with reference to the ground ground motion. The dynamic seismic performance of the building according to claim 1 and the seismic performance evaluation after seismic reinforcement, characterized in that the Q value representing the degree of sharpness is obtained and the seismic performance index C (C ₁ , C ₂ ) is obtained by the following equation: Method.

Where Ds is the structural characteristic coefficient of the building   The seismic performance index (C) from the vibration measurement result is a predetermined value or more, and it is determined that the seismic performance should be subjected to seismic renovation with caution. Dynamic seismic performance and seismic performance evaluation method after seismic reinforcement.   The vibration measurement is performed at the same place after the earthquake-proof repair, the amplitude spectrum and the natural period are compared, and if each room is within a predetermined value, it is determined that the earthquake-proof repair is acceptable. Of dynamic seismic performance of buildings and seismic performance after seismic reinforcement.

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