Nonlinear buffeting responses of a coastal long-span bridge under the coupled wind, wave and current loads

Abstract

The buffeting responses of sea-crossing bridges pose significant challenges due to the diverse terrain in the bridge region and intricate coupling effects between the environmental variables and structures. A novel Wind-Wave-Current-Bridge (WWCB) framework is proposed to assess the buffeting responses of coastal long-span bridges under coupled wind, wave, and current loads. By employing measured wind and wave data, the optimized C-vine copula and Ekman drift current theory are utilized to establish correlations among four environmental variables, namely wind speed, wave height, wave period, and current velocity. The nonlinear wave loads acting on the pile-cap foundations are computed using the potential flow theory and boundary element method (BEM). The interactions among wind, wave, current, and bridge involve both aerodynamic and geometric nonlinearity. The dynamic responses of the full bridge finite element model are iteratively solved until structural convergence is achieved using the Newmark-β method. Subsequently, the buffeting responses and the vibration mechanism of bridges are discussed in both the time and frequency domains. The results indicate that the nonlinear and correlation effects of wind, waves, and currents significantly affect the buffeting responses of the example bridge. Furthermore, the influence mechanism of wind and waves on the sea-crossing bridge is also discussed.