Determination of stochastic aerodynamic and aeroelastic coefficients for bridge decks

 

The incoming wind stream is usually described in a statistical sense (e.g. the design wind speed is obtained from the probability density function of the maxima), while the aerodynamic and aeroelastic characteristics of a body (e.g. the aerodynamic coefficients or the flutter derivatives) are always given as deterministic quantities. Nevertheless, the geometry of a bridge deck foreseen in the design stage is susceptible to imperfections during the construction stage of both the scaled model that is necessary for the tests in the wind tunnel and of the real prototype. The geometric imperfections, of an uncertain origin, can substantially alter the aerodynamic and aeroelastic behaviour of the deck, as has been witnessed in some real cases (e.g., the Sunshine Skyway Bridge), usually because of bi-stable regimes due to different separation mechanisms of the wall boundary layer. The study has the objective of obtaining the statistical characterisation of the above mentioned coefficients through the computational solution of the stochastic Navier Stokes equations.

 

 


Last updated: 21 January 2009