2001 Fiscal Year Final Research Report Summary
PERFORMANCE OF A SOIL-STRUCTURE SYSTEM UNDER NEAR-SOURCE EARTHQUAKES
| Project/Area Number |
11650486
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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 |
構造工学・地震工学
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| Research Institution | OKAYAMA UNIVERSITY |
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Principal Investigator |
CHOUW Nawawi OKAYAMA UNIVERSITY, DEPARTMENT OF ENVIRONMENTAL AND CIVIL ENGINEERING, ASSOCIATE PROFESSOR, 環境理工学部, 助教授 (70274016)
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| Co-Investigator(Kenkyū-buntansha) |
HIROSE Sohichi TOKYO INSTITUTE OF TECHNOLOGY, DEPARTMENT OF MECHANICAL AND ENVIRONMENTAL INFORMATICS, PROFESSOR, 大学院・情報理工学研究科, 教授 (00156712)
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| Project Period (FY) |
1999 – 2001
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| Keywords | Near-source earthquakes / Response of soil-structure system / Strong vertical ground motions / Simultaneous excitation / Behaviour of secondary structures / Soil-structure interaction / Nonlinear responses / Structure-secondary structure interaction |
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| Research Abstract |
The objective of this study is to investigate the characteristics of near-source earthquakes and their effect on the response of a structure-foundation-soil system as well as on the secondary structures. To reduce the effect of strong near-source earthquakes an approach consisting of steel springs and viscous dampers is recommended.
The investigations reveal:
At certain structure locations a consideration of horizontal ground motions alone will lead to an unrealistic response. While the vertical ground motions produces the maximum response, the horizontal ground motions produces no response.
The development of plastic hinges in the structure does not change this finding.
The time coincidence of subsequent peaks of the horizontal and vertical ground motions can cause much larger response than that produced by the horizontal ground motions. A simultaneous ground excitation should be therefore considered, especially in case of flexible structures.
The soil has a slight reduction effect on the
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structural response. For the vertical response of the secondary structure, however, response amplification up to 100% can be observed. Consequently, in the design the soft ground-structure interaction should be considered.
The effect of the interaction between secondary structure and structural member (SsSI) can cause an increase of the response of secondary structures, even though the vibration of the structural member, which supports the secondary structure, with and without SsSI are almost the same. For the design of a sensitive secondary structure the interaction between secondary structure and structural member is important.
The introduced reduction approach can activate rigid body motions in the structural response, not only in the horizontal but also in vertical direction. The viscous dampers reduce these motions. These activated rigid body motions reduce the relative deformation of the structural members, and cause smaller activated forces in the structure.
A reduction of the response of secondary structures can also be achieved. Less
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