Probabilistic evaluation of the aerodynamic behaviour of a bridge deck

The study of the probabilistic response of wind-excited structures and their reliability analysis need to take into account for the influence of a large number of uncertain parameters ascribed to meteorological data, structural characteristics and aerodynamic/aeroelastic behaviour. Although the latter one plays a key role in the reliability analysis and it shows high sensitivity to a number of parameters, the probabilistic description of the aerodynamic and aeroelastic forces remains scarce in literature. The present work aims at giving a contribution to the probabilistic evaluation of the aerodynamic behaviour of a bluff body, namely a bare bridge deck with trapezoidal cross section. The lower edge degree of sharpness and the oncoming turbulence length scale are retained as random variables. The computational solution of the resulting Stochastic Navier-Stokes Equations is performed by means of the adaptive form of the Multi-Element generalized Polynomial Chaos. As a result, the stochastic aerodynamic coefficients are described by their approximate probability density functions, which are related in turn to the aerodynamic regimes recognised for the case study.