POD-based modelling of distributed aerodynamic and aeroelastic pressures on bridge decks

To extend the knowledge of aerodynamic and aeroelastic behaviour of long-span bridges and to acquire an accurate wind-induced stress distribution of the bridge deck for fatigue analysis, the modelling of distributed aerodynamic and aeroelastic pressures on the bridge deck is imperative. A modelling method based on proper orthogonal decomposition (POD) is therefore proposed in this paper. The characteristic parameters of POD pressure modes, such as covariance modes, principal coordinates, pressure modal coefficients, pressure modal admittance functions and pressure modal derivatives are introduced. Indicial function-based parameter identification method is developed to identify pressure modal derivatives and admittances. Wind tunnel pressure tests were conducted on a spring-suspended sectional twin-box deck model of the Stonecutters cable-stayed bridge. With the pressure modal coefficients, covariance modes, and principal coordinates calculated from the measured distributed pressures, the pressure modal derivatives were identified. Thereupon, the aerodynamic and aeroelastic components of the pressure modes were separated, and the pressure modal admittance functions were then identified with the isolated aerodynamic components. The results show that the aerodynamic and aeroelastic components of wind-induced pressures can be separated successfully and the distributed pressures on the deck can be well reconstructed with a limited number of POD pressure modes.