1997 Fiscal Year Final Research Report Summary
Reliability estimation on dynamic responses of offshore structures
| Project/Area Number |
08650555
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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 | Kagoshima University |
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Principal Investigator |
KAWANO Kenji Kagoshima University, Department of ocean civil engineering, Professor, 工学部, 教授 (10026297)
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| Co-Investigator(Kenkyū-buntansha) |
VENKATARAMANA Katta Kagoshima university, Department of ocean civil engineering Associate Professor, 工学部, 助教授 (30244263)
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| Project Period (FY) |
1996 – 1997
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| Keywords | offshore structure / reliability / dynamic response / wave force / earthquake force / buoyancy type member / current force |
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| Research Abstract |
Offshore platform with large deck area may provide great possibilities to develop ocean spaces which may be used as resident areas, airport, power stations, etc.. Since these structures have very heavy dead loads, reaction forces on the base foundation become severe and necessitate very firm foundation system. If thses reaction forces can be reduced by some method such as large diameter members of buoyancy-type, the concept of large offshore platforms with the buoyancy type large diameter member may become popular in the offshore industry. In this study, emphasis is placed on examining the dynamic response of such a structure under the action of sea waves, currents and earthquakes. The main results are summarized as follows :
(1)The wave forces and the corresponding responses are amaller for the structure which has the buoyancy type member near the sea bottom. On the other hand, the current force gives significant effects on the response evaluations for the offshore structure with buoyancytype member and it is important to evaluate these effects.
(2)The dynamic responses of the offshore structure are influenced by the variation of parameters which are related to the wave force evaluation and structural characteristics. Since these random parameters also influence the response values, it is necessary to examine their effects on the responses and the reliability evaluation.
(3)It is necessary to develop rational methods to evaluate the reliability of offshore structures subjected to wave and earthquake forces which have entirely different characteristics in terms of excitation duration. One of the methods may be to compute the earthquake response first and then correlate it to the equivalent wave response and the wave loading conditions.
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