Three-dimensional simulations of suspension bridges under wind load: Numerical approach in the time domain

The paper outlines a framework for the analysis of bridges under wind excitation, based on structural finite element modeling and on cross-sectional aerodynamic load models. After a brief review, a time-domain load model for self-excited actions accounting for unsteadiness, mean angle of attack, along wind forces and displacements, asymptotically converging to the steady model is proposed. Afterwards, by means of a numerical example based on the quasi-steady load model, two facts are investigated: (1) the effects of the mean steady configuration on aerodynamic stability; and (2) the effects of load nonlinearities on the response. The results point out that: (1) the modifications in structural stiffness and aerodynamic properties due to steady deformation both affects the aerodynamic stability threshold, especially in case of bluff aerodynamics; (2) nonlinear loads produces larger structural response than linearized loads.