Comparison of the spatial correlation of the buffeting force on long span bridge and wind fluctuations

Results of previous wind tunnel testing have shown that the span-wise correlation of the buffeting force on bridge deck is greater than that of the turbulent components. Due to the limitation of wind tunnel size and model scale, above-mentioned results were usually obtained for smaller separation along the span and the turbulent flow was generated by passive method. In order to study of the span-wise correlation of the buffeting force with large separation and different turbulent flow field, thorouphty lift buffeting force is taken for instance in this paper. Theoretical analysis method is employed to establish a reasonable mathematic model, and then the difference of the span-wise correlation between buffeting force and wind fluctuations was investigated by means of the wind spectra simkulation in wind tunnel and in natural atmosphere, respectively. The buffeting force that better correlated span-wise than the wind fluctuations applies only to certain interval in turbulent flow simulated in wind tunnel, while as in the natural atmospheric turbulent field, the correlation of buffeting force is between the longitudinal and vertical oncoming flow fluctuations. Finally, the empirical coherence function proposed by Davenport is employed to verify the validity of the analysis method.