Strategies for identifying the two-dimensional aerodynamic admittance functions of a bridge deck

Pressure measurement experiments were carried out on three streamlined box girders with three geometric ratios of 1:50, 1:75 and 1:100 in five turbulent flow fields generated by grids. The turbulence intensities only affected the root-mean-square (RMS) of the pressure coefficients in the flow separation zone, while the turbulence integral scales affected the RMS of the pressure coefficients over the entire cross-sections. The spanwise correlations of the fluctuating winds and buffeting forces mainly varied with the turbulence integral scales. New strategies are proposed to identify the two-dimensional aerodynamic admittance functions (2D AAFs) using the two-wavenumber approach. The two-wavenumber coherence functions of fluctuating winds or buffeting forces obtained through new strategies do not need to use the empirical spanwise root-coherence function models compared to the traditional strategy. A complete analysis of 2D AAFs based on different strategies was performed. The determined 2D AAF using spanwise root-coherence function models varied with the kinds of spanwise root-coherence function model and relied on spacings chosen to fit, which caused the 2D AAF to vary in size. Therefore, the strategy without any spanwise root-coherence function models is recommended, and it is confirmed to give reliable and repeatable bridge deck 2D AAFs.