A Computational Framework for the Aerodynamic Shape Optimization of Long-Span Bridge Decks

A computational framework for automated shape modification of long-span bridge decks is proposed. The proposed technique involves the use of computational fluid dynamics (CFD) for aerodynamic analysis, surrogate models for response function approximation and numerical optimization routines for iterative selection of optimal shapes. A brief review of aerodynamic shape modification measures for decks of long-span bridges is presented. The framework is applied for aerodynamic fairing design of a typical plate-girder stiffened deck with the objective of reducing the lateral wind load and improving aerodynamic stability under smooth flow. Numerically evaluated optimal fairing shapes are compared with that of Bronx Whitestone Bridge and Deer Isle Bridge. It is shown that sharper triangular fairings are effective to reduce wind induced drag, but shorter fairings with height around 60% to 70% of deck depth are effective to improve the aerodynamic stability of elongated H-shaped decks. Furthermore, asymmetric triangular fairings are found to be effective to improve the aerodynamic performance of asymmetric decks.