모니터링 시스템의 계측자료를 기반으로 한 닐슨아치 교량의 내풍 안정성 평가

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 mode shape of the bridge is antisymmetric and the is symmetric. Also, the dominant vibration of the bridge is the vertical mode. According to these results, the vertical vibration mode of this Nielsen arch bridge is prior to the first for the estimation of wind resistance capacity.