| Project/Area Number |
62460149
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| Research Category |
Grant-in-Aid for General Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Research Field |
土木構造
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| Research Institution | Kyoto University |
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Principal Investigator |
SHIRAISHI Naruhito Professor, Faculty of Eng., Kyoto University, 工学部, 教授 (40025903)
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| Co-Investigator(Kenkyū-buntansha) |
SHIRATO Hiromichi Research Associate, Faculty of Eng., Kyoto University, 工学部, 助手 (70150323)
FURUTA Hitoshi Lecturer, Faculty of Eng., Kyoto University, 工学部, 講師 (70109031)
MATSUMOTO Masaru Assoc. Professor, Faculty of Eng., Kyoto University, 工学部, 助教授 (00026270)
MITSUTA Yashushi Professor, Desaster Prevention Research Inst., Kyoto Univ., 防災研究所, 教授 (90027219)
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| Project Period (FY) |
1987 – 1988
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| Project Status |
Completed (Fiscal Year 1988)
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| Budget Amount *help |
¥6,000,000 (Direct Cost: ¥6,000,000)
Fiscal Year 1988: ¥3,000,000 (Direct Cost: ¥3,000,000)
Fiscal Year 1987: ¥3,000,000 (Direct Cost: ¥3,000,000)
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| Keywords | Super-long spanned bridge / Aerodynamic Stability / Natural Wind Chracteristics / Failure Probability / Fatigue Failuer / Flutter / Vortex-induced Oscillation / 台風係数 / 耐風安定性 / 安全性評価 / 自然強風特性 |
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| Research Abstract |
Main problem in the design of superstructure of long-span bridge is the aerodynamic stability. Therefore, it is an essential task to know the behavior of natural wind at the construction site as well as its aerodynamic properties.
In this research study, by using the failure probability index of the bridge structure to aerodynamic response, the first stage of failure due to flutter was determined as an object of the failure probability in 1987. The vortex-induced oscillation was also objected. In 1988, failure probability in 1987. the vortex-induced oscillation was also objected. in 1988, failure probability was determined with the consideration of both the effect of vortex-induced oscillation and buffeting, and damage accumulation resulting from fatigue was also determined in order to evaluate fatigue failure.
Furthermore, for evaluating natural wind, because both an aerodynamic behavior of bridge structures and the characteristics of natural wind are strongly depended on the wind direc
… More
tion, wind speed characteristics of strong and normal wind were determined for each wind direction.
From these results, failure probability of seven suspension bridges due to flutter under strong wind were determined. For double-deck bridges, the thickness of web and flange of chord member is thicker than other bridges, and the result of the evaluation fell in the safety side. For boxgirder bridge, based on the characteristics of vibration response obtained from wind tunnel test, the method for evaluating failure probability due to both vortex-induced oscillation and buffeting is proposed. Evaluated result by using this method showed that the failure probability depends mainly on the first mode of vortex-induced oscillation. It was also found that the failure probability is extremely sensitive to the material strenght.
For estimating strong wind, the wind data of the 133 places in Japan for 15 years were used. Region of strong wind, Weibul parameter, and typhoon factor were determined. Finally, the map of typhoon factor was established.
From this research, the characteristics of natural wind and the evaluation of its effect on the structural stability were proposed. This results are considered to be useful for evaluation of the aerodynamic stability of the long-span bridge. Less
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