Driving Safety Analysis of Road Vehicle on Long-Span Bridge Considering Nonstationary Wind

Long-span bridges in mountainous areas are usually exposed to nonstationary winds (e.g., thunderstorms), which pose a significant threat to the driving safety of vehicles. However, current analysis on the wind–vehicle–bridge interaction was mainly implemented based on the assumption of stationary wind input, which would lead to the distortion in the assessment of driving safety under nonstationary extreme wind events. In this study, a nonstationary wind–vehicle–bridge coupling analysis framework was found to investigate the dynamic response and driving safety under nonstationary events. Firstly, the Wavelet–Hilbert scheme was introduced to simulate the nonstationary wind velocity, and the two-dimension indicial function was employed to model the transient aerodynamic loads. Then, the nonstationary wind–vehicle–bridge coupling system was developed, and the separate iteration method was employed to obtain the response of the coupling system. Finally, the driving safety is evaluated based on statistical accident risk coefficients, derived from wheel contact forces. The results show that the vertical contact forces transference ratio, lateral contact forces, and vehicle accident risk coefficients under nonstationary winds are higher than those resulting from equivalent stationary winds. In addition, the accident risk coefficients increase with the transient wind velocity, duration, and vehicle velocity. In particular, the risk coefficient increases by approximately 201%, 36%, and 79%, respectively, with the increase in transient wind velocity, duration, and vehicle velocity.