Computational method for the prediction of dynamic response of long-span bridges due to unsteady wind load

A two step computational method is proposed to predict the dynamic response of the long span bridges by unsteady wind loads due to vortex shedding. Computational fluid dynamics (CFD) analysis using a 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 under unsteady wind loads are followed to investigate vortex excited oscillations of the bridge. For an economical application of the computational method proposed, an approximate calculation method of unsteady wind loads is presented. Reasonable agreements are observed between the predictions by the computational analyses and the existing wind tunnel measurements, and between the prediction by unsteady wind loads calculated through CFD and the prediction by approximated unsteady wind loads.