Simplified flutter prediction for bridges with bluff cross-section

Wind-induced flutter of bridges occurs as coupled torsional and vertical oscillation, or uncoupled torsional oscillation. Bridges with bluff, non-streamlined sections are prone to torsional flutter. Prediction of torsional flutter on the basis of measured aerodynamic derivatives essentially corresponds to the prediction of coupled flutter, although, compared to the latter, it can be largely simplified. The theoretical background is discussed and the given formulae are checked against empirical data. It is found that simplification is recommendable only up to a certain degree