Identification of quasi-stationary aeroelastic force coefficients for bridge deck sections using forced vibration wind tunnel testing

The use of a quasi-stationary model for aeroelastic phenomena is a common approach for the description of the related interaction forces at line-like, slender structures under wind action. The identification of quasi-stationary force coefficients is introduced through a short derivation of a quasi-stationary model for self-excited forces of bridge flutter. The quasi-stationary model is put into relation to an instationary model using flutter derivatives. The aerodynamic force coefficients are identified using three different procedures: firstly, measurements at rigid, static models of bridge girders, secondly, dynamic measurements with heave motion and rotation and finally, dynamic measurements with a horizontal motion. The identified coefficients are compared and discrepancies between the drag coefficients, differently identified using the three mentioned methods, are detected. Such differences give an influence to the analysis of the aeroelastic stability of a structure as the drag coefficient contributes to the aeroelastic damping. A short discussion concludes the paper.