Research Trends and Results

Arrangement/Analysis for earthquake
observation records aiming for enhancement inaccuracy for evaluating earthquake intensity ofbuildings
AZUHATA Tatsuya (Ph.D), HeadARAI Hiroshi (Dr. Eng.), Senior Researcher
Structural Standards Division, Building Department
INOUE Namihiko, Senior Researcher
Standards and Accreditation System Division , Building Department(Key words) Earthquake observation, Dynamic Interaction of Structure/Ground, Earthquake force
evaluation

1. Foreword

random vibration theory and compared.1)

We introduce the outline ofFor instance, in regard to the observation

arrangement/analysis methods deliberated in thebuilding shown in Figure 2, the Fourier spectrum

comprehensive technological development project

ratio is indicated in Figure 3 from observation

titled Development of aseismic capacity forrecords. In proportion to the ratio of massivebuildings corresponding to the sophistication of

deformation of ground spring, the building

earthquake vibrations information. With respect

deformation of the coupled system is clarified toto the earthquake behavior of actual buildings,

greatly be reduced in comparison with thesince the dynamic interactive effects offoundation fixed system.

structures/grounds have affect, we have made it a

3. Conclusion

subject to comprehend this quantitatively.

In order to make technological data for

2. Outline of method

deliberating designing earthquake intensity for

We will illustrate the flow of method in thebuildings, we have currently been applying theFigure 1. According to simultaneous observation

methods illustrated

for ground and the inside of building (apex andobservation buildings and compiling its results.

bottom), the Fourier spectrum ratio, whichherewith tostill

more[Reference]indicates relations between the ground surface

1) Okano, Azuhata, others: Building response

and the inside of building, is obtained. From thedecreasing effects presumed from observation

Fourier spectrum ratio, the original dimension ofrecords, collected papers of the Architectural

sway model or sway rocking model is fixedInstitute of Japan

including input loss effects. Using identification
results, coupled system responses receiving
foundation fixation and dynamic interaction
effects can be obtained by analysis using thez1

calculation for (building
apex/ground surface,m1HθFIMH1 θＩH1 x1
ｙＩ

k1,c1

θ0=θFIM+θＩ

kHH,cHH
m 0 I0building bottom/ground

Height：14.03m

Fourier Spectrum ratio① Fourier Spectrum ratioyFIM

Flat surface size：8.06m×65.7m
kRR,cRR

surface, building

Class of ground：2nd class

apex/building bottom. )

ｙＩ

yFIM
z0

Sway Rocking model② Identification andoriginal dimensions andinput loss effects of Sway

Upper part structure：Wall type RC structure

5F/GL
5F/1F
1F/GL101Longsidedirection

長辺方向0.1

Foundation structure：PC pile (PC 杭)

0.11Frequency (Hz)

10(The 2011 off the Pacific coast of Tohoku

Seismometer5FEarthquake)

地震計

Figure 3 Fourier Spectrum ratio
1FGL

Figure 2 An example of observation building

Model (S. Model) or Sway
Rocking Model (SRSR model) earthquake responses receiving foundation
fixed model and dynamic interactions and compare using
the random vibration theory.
*Deliberate two cases: A case to consider dynamic
interactions of inertia only (II); a case to consider
both interactions of inertia and input (II+KI).

Figure 1 Flow of method

3.0

1.0の建物変形③Obtain earthquake response of series model (S model or1.5(Sum of deformation
deformationcomposition)/building(変形成分の和)/基礎固定系
of foundation fixed model※Spectrum Fitting method

建物変形

Spectrum ratio.

Building deformation in seriesmodel/Building deformation of
連成系の建物変形/基礎固定系のfoundation fixed modelModel) from Fourier

0.50.0

IIII+KI

Building
建物 spring
Ground
地盤ばね

2.0Large
deformationof groundspring1.00.0Figure 4 Examples of analysis results

Deformationof groundspring is large