Aero-structural Optimization of Streamlined Twin-Box Deck Bridges with Short Gap Considering Flutter

Shape and size design of twin-box decks involves managing a number of highly sensitive deck features, including aerodynamic, stiffness, and mass properties, which leads to important and complex changes in the aeroelastic and structural performance of the bridge. This design problem is addressed in this study by recasting it as an aero-structural optimization problem. A generic short gap twin-box bridge is optimized considering 164 shape and size design variables and 2,753 design constraints. The proposed methodology obtains sustainable and economical optimum designs by minimizing the required amount of material to build the bridge, while meeting the performance and safety requirements in the structural and flutter design constraints. Furthermore, parametric studies provide very valuable information to better understand the role of different design variables on flutter. It has been found that the gap size plays an important role in managing the flutter requirements in the design process. (C) 2021 American Society of Civil Engineers.