A two-step computational method for the analysis of vortex-induced oscillation of the bridge

As a practical alternative to the preliminary wind tunnel tests in the wind-resistant design of the bridge structures, an efficient two-step computational method is proposed to predict the dynamic response of the long-span bridge structures by unsteady wind loads due to vortex-shedding. By decoupling the wind-structure interaction problem, firstly computational fluid dynamics analysis using two-dimensional model of the bridge deck section are carried out to evaluate the unsteady wind loads on the bridge deck. Three-dimensional dynamic analysis of the bridge structure under unsteady wind loads are followed to investigate vortex-excited oscillations of the bridge. Reasonable agreements are obtained between the predictions by the computational analyses and the existing wind tunnel measurements. Although various assumptions introduced in the modeling process should be justified to systematically augment the computational method, it may serve as a preliminary design supporting tool for evaluation of dynamic response of the bridge due to vortex-induced unsteady wind load before undertaking serious wind tunnel tests.