Mitigation of vortex-induced vibrations in bridges under conflicting objectives

Aerodynamic performance of long-span bridges can be improved by retrofitting cross-sectional shapes or by adding tuned mass dampers. When both the approaches are used simultaneously, the design problem may become too complicated to solve by engineering judgment. The complexity becomes even greater in a real world problem in which both the performance and the cost have to be considered. We propose a multi-objective based approach to obtain optimal solution of the design problem. The approach effectively deals with highly nonlinear design space and the conflicting objectives between the performance and the cost. Due to the conflict of the two objectives, multiple optimal solutions are obtained, which are called Pareto-optimal solutions. The final design is obtained considering the cost and the performance criteria. The proposed method is applied to the mitigation of vortex-induced vibrations, but its general framework is applicable to any other aerodynamic problems.