Buffeting response of a suspension bridge in complex terrain

The buffeting response of a suspension bridge in complex terrain is studied based on full-scale data from sonic anemometers and accelerometers installed on the Lysefjord Bridge in Norway. The influence of the topography on the wind field and the associated effects on the displacement response are investigated. The two main wind conditions observed display different characteristics, which requires a case by case approach, and a refined description of the wind co-coherence. The identification of the mode shapes and modal damping ratios is carried out using ambient vibration data as a verification procedure. The buffeting response of the bridge is computed in the frequency domain, and compared to the recorded response in terms of standard deviation and power spectral density of the displacement response. The overall comparison is found satisfactory, although some discrepancies are observed. These are attributed to large yaw angles and non-stationary wind fluctuations caused by the influence of a complex topography on the flow properties.