| Project/Area Number |
12650574
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| Research Category |
Grant-in-Aid for Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Building structures/materials
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| Research Institution | Kobe University |
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Principal Investigator |
KUSAKABE Kaoru Kobe Univ., Faculty of Engineering, Professor, 工学部, 教授 (80027250)
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| Co-Investigator(Kenkyū-buntansha) |
MAEDA Yukinori Kobe Univ., Faculty of Engineering, Research Associate, 工学部, 助手 (00116253)
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| Project Period (FY) |
2000 – 2001
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| Project Status |
Completed (Fiscal Year 2001)
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| Budget Amount *help |
¥3,600,000 (Direct Cost: ¥3,600,000)
Fiscal Year 2001: ¥1,700,000 (Direct Cost: ¥1,700,000)
Fiscal Year 2000: ¥1,900,000 (Direct Cost: ¥1,900,000)
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| Keywords | surface layer / complex stiffness / nonlinear earthquake response analysis / ground compliance / impedance / pile foundation / rational function / 地盤-建物連成系 / 表層地盤の増幅 / 土の非線形 / 地盤剛性の緩み領域 / 地盤-杭基礎系 / 薄層要素法 / 杭基礎の起振機試験 / 起振機実験 / 地盤の逆算バネ / 地盤の非線形 / 群杭-地下構造物 / 地盤の減衰効果 / ウエーブレット変換 / 建物振動特性の同定 |
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| Research Abstract |
During 1995 Hyogo-ken Nanbu Earthquake we have observed conspicuous concentration of damage in an extended area as a form of the so-called damage belt whose width was very narrow compared to its length. One of causes for this damage is the complexity of the deep underground structures including the earthquake fault. Another cause is the effects of surface layers.
In this study, we discussed about the amplification effect of surface layers, the evaluation of complex stiffness of surface layers and the interaction effect between soil layer and structure. Then we proposed the earthquake response analysis method considering these effects of surface layers and the soil-structure interaction when building structures are subjected to ruinous or disastrous earthquake motion like 1995 Hyogo-ken Nanbu Earthquake.
The complex stiffness of surface layers is evaluated by dynamical ground compliance (DGC) and impedance of soil-embedded base or pile foundation considering surrounding nonlinear soil media. Then the complex stiffness of surface layers is expressed by using the rational function of DGC and replaced with frequency-dependent spring-dashpot system.
Results are as follows ; (1) The amplification effect of surface layers strongly depends on the conditions (depth, stiffness etc.) of the surface layers. (2) Simple surface layers can easily be replaced with simple spring-dashpot system, but deep surface layers becomes to more complex spring-dashpot system. (3) We must analyze earthquake response of building structure considering the interaction effect of soil-structure, because surface layers often have bad effects on earthquake response of building. (4) Nonlinear earthquake response analysis of soil-structure interaction system becomes easier by using rational function as the complex stiffness of surface layers.
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