Dynamic Response of Road Vehicle–Bridge System Under Wake-Induced Vertical Vibration of Long-Span Parallel Cable-Stayed Bridges

Aerodynamic interference between parallel bridges significantly alters the wind environment on bridge decks and causes wake-induced vibrations (WIV) that are difficult to suppress, thereby posing challenges to driving safety. In this study, a numerical simulation model was developed to analyze the aerodynamic characteristics of moving vehicles subjected to wake flows generated by parallel bridges, with validation performed through wind tunnel experiments. A coupled vehicle–bridge vibration analysis model incorporating the effects of wake flow was subsequently established, and the equivalent representation of non-stationary wake-induced forces (WIF) was examined. Parametric studies were conducted to investigate the influence of vehicle entry timing, bridge vibration modes and amplitudes, vehicle speed, and wind barriers on driving safety. Results demonstrate that the shielding effect of the windward bridge reduces the aerodynamic force coefficients experienced by vehicles on the leeward bridge. Compared to single-bridge scenarios, vehicles on the leeward bridge exhibit lower lateral acceleration responses but significantly increased vertical responses due to vertical WIV. Furthermore, vehicle responses are found to increase with greater bridge vibration amplitude, higher vibration mode order, and increased vehicle speed. These findings provide insights into the aerodynamic and dynamic interactions in parallel bridge systems and their implications for vehicle safety.