Spanwise layout optimization of aerodynamic countermeasures for multi-mode vortex-induced vibration control on long-span bridges

Abstract

Aerodynamic countermeasures are widely used to control vortex-induced vibration (VIV) on long-span bridges. However, due to the lack of appropriate three-dimensional (3-D) VIV analysis approach, these countermeasures are usually installed along the entire span of the bridge deck, leading to excessive costs. This study proposes an optimization method for the spanwise layout of aerodynamic countermeasures, aiming to achieve an economical control scheme for multi-mode VIV. An improved mode-by-mode 3-D VIV analysis approach is developed based on the generalized polynomial model to predict the VIV responses of the bridge with different spanwise layouts of aerodynamic countermeasures. The genetic algorithm (GA) is then employed to search for the most economical layout scheme with constraints of limited multi-mode VIV responses. Two alternative types of search spaces for the optimization are presented. The effectiveness of this optimization method is demonstrated on a long-span suspension bridge in conjunction with finite element simulation and wind tunnel tests. The results show a noteworthy reduction in the use of aerodynamic countermeasures, thus highlighting the necessity of countermeasure layout optimization.