Reliability based design optimization for bridge girder shape and plate thicknesses of long-span suspension bridges considering aeroelastic constraint

Reliability based design optimization (RBDO) for deck shape and thicknesses of the steel plates that form a box girder of long-span suspension bridges is performed considering probabilistic flutter constraint. The entire process was carried out fully computationally including the definition of flutter derivatives. Surrogate models were constructed to estimate the aerodynamic response of the bridge for different deck shapes based on the results from a series of CFD simulations. Some of the aerodynamic coefficients were validated by wind tunnel tests. Flutter derivatives were then estimated using quasi-steady approach for the evaluation of critical flutter velocity. Uncertainty in the aerodynamic coefficients from CFD simulations as well as the extreme wind speed at the bridge site were considered. The formulated methodology was applied to the Great Belt East Bridge.