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Title |
Estimation of Wind Resistance Capacity of Nielsen Arch Bridge Based on Measured Data From Monitoring System
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Keywords |
닐슨 아치교 ; 와류진동 ; 모드 형상 ; 모니터링시스템 ; 내풍 안정성 ; Nielsen arch bridge ; Vortex-induced vibration ; Mode shape ; Monitoring system ; Wind resistant capacity |
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Abstract |
The wind resistant capacity of bridges with a span of less than 200m is typically evaluated by Wind Resistant Design Manual for Highway Bridges in Japan. Also, the first vertical frequency plays an important role in the evaluation of their aerodynamic performance. An unexpected vortex-induced vibration of Nielsen arch bridge with span of 183m designed by this manual has been measured by monitoring system during typhoon. The amplitude of vibrations was about 2 times than the allowable vibration displacement. This paper presents the feature of vortex-induced vibration of this Nielsen arch bridge based on measured wind velocity, wind direction, and responses at midspan of main girder. From the result of FFT, the 1st mode shape of the bridge is antisymmetric and the 2nd is symmetric. Also, the dominant vibration of the bridge is the 2nd vertical mode. According to these results, the 2nd vertical vibration mode of this Nielsen arch bridge is prior to the first for the estimation of wind resistance capacity.
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