以湖北荆沙长江大桥为背景,通过均匀流场和紊流场节段模型测力风洞试验对典型扁平双边肋主梁断面抖振力的频谱特性和气动导纳函数进行了研究。结果表明,由于特征紊流的存在,均匀流场中也存在抖振力,而且其频谱具有一个或一个以上的峰值;在紊流度约10%的紊流场中,特征紊流效应依然存在,其引起的抖振力幅值与均匀流场中相当,但由于来流紊流产生抖振力明显占据主导地位,因此特征紊流的作用并不明显;气动导纳与Sears函数有明显区别,而且并非随频率增加而呈单调下降趋势,在来流和特征紊流频谱峰值点附近均存在相应的峰值。
Taking Jingsha Yangtze Bridge as an example, buffeting force spectra characteristics and aerodynamic admittance functions for typical flat double-girder bridge deck have been analyzed by segmental modeling's dynamometer wind-tunnel experiment in uniform flow and turbulence flow. The results indicated that buffeting forces exist in uniform flow because of signature turbulence and its spectra have one or more peaks; signature turbulence's effect also exists in turbulence flow when the turbulence intensity is about 10%, and the amplitude of buffeting force caused by signature turbulence is comparative with that in uniform flow. The buffeting force caused by wind turbulence is evidently significant compared with that by signature turbulence in turbulence fields. Aerodynamic admittance functions are not monotonically decreasing as Sears function, they have peaks both in the vicinity of frequency corresponding to wind turbulence and signature turbulence wind spectra peaks.