Time-Domain Analysis of the Buffeting Response of Long-Span Bridges

This paper deals with the time-domain analysis of the response to turbulent wind of long-span bridges. Self-excited forces are modelled via indicial functions, which are determined from the flutter derivatives measured in the wind tunnel for a realistic bridge deck section. The buffeting response of a two-degree-of-freedom model and a full structural model of a long-span suspension bridge are determined. A time-domain approach is suitable to easily account for the multimode contribution to the response and for the aerodynamic coupling between these modes, as well as for the nonlinear properties of the structure and of turbulent load. The key role played by the self- excited forces for the determination of the subcritical response of bridge structures is clearly highlighted and discussed in the paper.