Effects of turbulence integral scale on the buffeting response of a long-span suspension bridge

Abstract

In this paper, the effects of the turbulence integral scale on the buffeting response of a long-span suspension bridge are studied via the proposed three-dimensional (3D) two-wavenumber buffeting analysis method. The root mean squares (RMS) of the buffeting lift and displacement of the streamlined bridge girder are analyzed in cases with different ratios of the turbulence integral scale to the half-width of the bridge girder (γ) and mean wind speeds. To achieve a deeper understanding of the effects of the turbulence integral scale, the spectra of wind fluctuations, buffeting forces and vertical buffeting displacements for typical ratios of γ and mean wind speeds are compared. The results demonstrate that the equivalent buffeting lift per unit span and vertical buffeting displacement show different variation trends as γ increases. The effect of the turbulence integral scale on the buffeting lift forces is independent of the mean wind speed, and becomes more significant for the vertical buffeting displacements at high mean wind speeds in cases with small values of γ. The effectiveness and accuracy of the numerical analysis is verified by full-bridge aeroelastic wind tunnel tests in large integral scale turbulent fields. The present study shows that it is essential to consider the effects of the turbulence integral scale on the buffeting responses of long-span bridges. To achieve reliable results, accurate estimations and appropriate simulations of γ are of high importance in both numerical analysis and wind tunnel tests for the buffeting predictions of long-span bridges.