Identification of bridge aerodynamic coefficients from measured displacement or acceleration

This paper identifies the aerodynamic coefficients of a bridge deck arising from buffeting effects under wind load from displacement and acceleration responses of the structure. The identification equation is formulated in state space, and it is solved with the least-squares method. The fluctuating wind field is simulated with an AR model including the spatial coherence of the independent Gaussian stochastic processes. A three-span continuous concrete box-girder bridge deck located in an open terrain is selected as an example for validating the proposed method. The identified aerodynamic coefficients from displacement response and from acceleration response are compared for different scenarios of sensor number. Numerical simulations with non-zero initial conditions show that the proposed method can identify the aerodynamic coefficients very accurately from a small number of noisy measured displacements or accelerations. Results also indicate that acceleration is more effective for identifying the aerodynamic coefficients of a bridge deck than displacement response.