The transient temporal response of a flexible bridge deck subjected to a single gust

Temporal simulations are increasingly performed in wind effects analysis of flexible structures. By comparison with classical techniques such as spectral methods, temporal simulations provide the advantage of easily combining different kinds of loads, can take nonlinearities into account and also provide the only way to reproduce transient behaviors. In that context this study deals with the transient response of a two-degrees-of-freedom streamlined bridge deck section subjected to a single gust. Experimental evidence of the potentially high level of transient energy amplification due to that kind of extraneous excitation have been recently demonstrated for an airfoil section and for a streamlined bridge deck section, below the critical coupled-mode flutter wind speed. The present study then focuses on the validation of a time-dependent model, based on a simple formulation of both the motion-dependent and the buffeting forces, for catching that kind of transient behavior. A parametric study is also made in order to highlight the impact of the pitch–plunge frequency ratio on the energy amplification below the critical condition.