Estimation of aerodynamic derivatives from ambient vibration data

The paper discusses the estimation of aerodynamic derivatives from a general type of ambient vibration data. The buffeting response data of a bridge section model, the full-bridge aeroelastic model and the associated prototype structure is analysed by a system identification method. The three sets of the resulting aerodynamic derivatives are found to be in a general agreement, but there are also some discrepancies between coupling terms. The first analysis of the data from the full bridge aeroelastic model as well as the prototype structure assumes vertical and torsional response components only, and the dominance of the two lowest symmetric modes. Such a model needs a further refinement in order to allow for a more general type of mode coupling as well as to include horizontal response in the analysis.