報告書番号

380040

タイトル（和文）

原子力発電所等短周期構造物の耐震設計用地震入力の評価（その１基盤レベルでの強震地動スペクトルき平均的特性）

タイトル（英文）

ESTIMATION ON EARTHQUAKE DESIGN INPUT TO SHORT PERIOD STRUCTURES SUCH AS NUCLEAR POWER PLANTS (1) -CHARACTERISTICS OF AVERAGED FOURIER AMPLITUED SPECTRA ON BEDROCK-

概要 （図表や脚注は「報告書全文」に掲載しております）

基盤レベルにおける強震地動スペクトル特性の一般特性を知ることは，原子力発電所を初めとする重要構造物の耐震設計用地震入力の策定のためには重要な課題である。本報告は，基盤レベルにおける平均的なスペクトル特性の一般性質を，断層運動と結びつけて定性的に考察したものである。その結果，金井（１９５８）の“いわゆる速度スペクトル”が一質点系の残留振動の速度応答スペクトルと考えると本報告のスペクトル解析結果は，定性的に一致する。また，同一地点における観測記録の平均加速度フーリェスペクトルは，その地点の地盤の伝達特性に相似なスペクトル特性を示す。さらに，理論フーリェスペクトル振巾は，実地震動スペクトル振巾を過少評価するために，周波数領域での振巾補正が必要である。

概要 （英文）

IN ORDER TO QUALITATIVELY STUDY THE FOURIER SPECTRAL CHARACTERISTICS OF STRONG-MOTION EARTHQUAKE RECORDS ON BEDROCK, THE FOURIER SPECTRA OF 17 ACCELEROGRAMS WHICH WERE RECORDED IN JAPAN,ARE ANALYZED. THE SHEAR-WAVE VELOCITIES(VS)FOR THESE RECORDS OF THE SITES ARE AS FOLLOWS: SITE A1,VS=1.3KM/SEC AND SITE B1,VS=1.6KM/SEC. THE ACCELERATION SPECTRA ON BEDROCK ARE ESTIMATED BY STATISTICALLY ANALYZINGTHE ABOVE 17 ACCELEROGRAMS METHOD OF LEAST-SQUARE IS USED TO OBTAIN THE AMPLITUDE OF THE FOURIER SPECTRUM BETWEEN PERIOD 0.1 SEC AND TM SEC. THE RESULT OF THIS INVESTIGATION SUGGESTS THAT THE AVERAGED FOURIER AMPLITUDE SPECTRA ON BEDROCK CAN BE CONSIDERED TO FLAT STATISTICALLY DURING THE ABOVE PERIOD RANGE. THIS QUANTITATIVE RESULT AGREES WELL WITH THECHARACTERISTICS OF THEORETICAL SPECTRA CALCULATED BY PROPAGATING FAULTMODEL. THE PERIOD TM AND THE CORNER FREQUENCY(SAVAGE,1972)ALSO AGREE WELL FOR MAGNITUDE LESS THAN 6.0. KANAI(1957),IN HIS STUDY ON THE CHARACTERISTICS OF THEORETICAL SPECTRA ON BEDROCK,CONCLUDED THAT THE VELOCITYSPECTRUM SEEMED TO BE FLAT. HOWEVER,HE HAD COMPUTED THE VELOCITY SPECTRUM FROM THE RESPONSE OF A SINGLE DEGREE OF FREEDOM SYSTEM. HIS CONCLUSIONS AGREE QUITE WELL WITH THE RESULTS OF THIS STUDY. FROM THIS PAPER,IT CAN BE CONCLUDED THAT THE SHAPE OF THE AVERAGED SPECTRA ON BEDROCK SHOULD BE FLAT DURING PERIODS 0.1SEC AND TM SED(FOR MAGNITUDE LESS THAN 6.0,THE CORNER FREQUENCY SHOULD BE REPLACED WITH TM). IN OTHER WORDS,THERESULTS INDICATE THAT THE AVERAGED FOURIER SPECTRA OF ACCERELOGRAMS OBSERVED AT A GIVEN SITE SHOULD BE SIMILAR TO THE TRANSFER FUNCTION OF THAT SITE. HENCE,THE SITE DEPENDENT SPECTRA PROPOSED BY MANY INVESTIGATORS(HOUSNER,1952;NEWMARK ET AL,1973;SEED AT AL,1974;KIREMIDJIAN AND SHAH,1978)REPRESENT THE TRANSFER FUNCTION OF THE SITE.

報告者

キーワード