Abstract: On the basis of simulation of structure of Jingsha River Yangtze Bridge, the aerodynamic admittances are studied by means of cross-correlation spectrum recognition with data gotten from segmental modeling＇s dynamometer wind-tunnel experiment in turbulence flow. Through comparison with traditional method, it is found that aerodynamic admittances gotten by cross-correlation spectrum recognition are less than traditional ones and Sears function on quantity in general, although both results had the same trend of change with the rise of reduced frequency. The buffeting force is calculated through complex aerodynamic admittances, and the spectrum analysis is also carried out. Comparing with those data measured from experiments, it is found that both of them have the same trend of change with the rise of reduced frequency, although they have certain differences in quantity. Through the comparison of buffeting force spectra in different turbulence flow, whose turbulence intensity are 6%, 10%, 20% respectively, with the consideration of different wind attack angle ranging from -5°to ＋ 5°, it is found that the difference of quantity between results calculated by complex aerodynamic admittances and those measured from experiments are steady and almost independent on the change of wind attack angle and turbulence intensity.

Key words: buffeting force , aerodynamic admittance , cross-correlation spectrum recognition , flat double-girder bridge decks , spectra ;

摘要： 以湖北荆沙长江大桥为背景,通过紊流场测力试验对气动导纳的互功率谱识别法进行了研究。通过与传统 方法比较,发现互功率谱法计算得到的等效气动导纳整体上偏低,且低于Sears函数,但随折减频率变化的趋势上 看,与传统算法无明显差异。由互功率谱法计算得到的复气动导纳计算抖振力,并进行频谱分析,与实测抖振力自 功率谱比较发现,计算得到的抖振力自功率谱随折减频率变化的趋势与实际抖振力自功率谱吻合较好,但存在一 定数量上的差异。通过对紊流度为6%、10%、20%的三种紊流场中-5??~+5??风攻角下计算值与实验值的比较发 现,计算抖振力谱与实际抖振力谱的相对差异没有随紊流度和来流风攻角变化而变化的趋势,且相对差值较为稳 定。

关键词: 抖振力, 气动导纳, 互功率谱法, 扁平双边肋主梁, 频谱