Multi-mode aeroelastic and aerodynamic analysis of long-span bridges.

摘要

A fully coupled three-dimensional analytical model for the aeroelastic and aerodynamic analysis of long-span bridges has been developed. In the design stages it is important to be able to investigate the flutter stability, buffeting response, and vortex-induced response of a long-span bridge to wind excitation using rational and reliable procedures. These procedures must be able to estimate faithfully the response of the prototype, but allow for simple incorporation of the frequent changes that occur during the design process. The analysis procedure considers the effect of multiple modes of vibration acting simultaneously, in contrast with the single-mode approaches adopted in the past. This accounts for the complex modal interactions and aeroelastic coupling that can be expected in the super-long and flexible decks of suspended-span bridges being constructed or considered. Combined with results from a section-model test, the coupled analysis can yield valuable information on the suitability of a deck cross section and the structural configuration.; This dissertation outlines a procedure to compute the multi-mode aeroelastic and aerodynamic response of a long-span bridge to wind-induced excitation. This method was applied to evaluate the response of several long-span bridges and the results compared with those obtained from a single-mode analysis procedure. Results show that while in many cases the single-mode procedure is sufficient, in some cases consideration of the additional complexity provided by aerodynamic or aeroelastic interaction is essential.