Modeling of Vehicle–Bridge Interaction with Driver Behavior and Vehicular Safety Analysis during Earthquakes

Seismic isolation technology has enhanced bridge seismic performance, but seismic-induced dynamic responses still may threaten passing vehicles even if the bridge remains undamaged. This paper proposes an accident evaluation model for moving vehicles crossing long-span bridges under seismic excitation. A feedback mechanism integrating the bridge motion state into the driver’s behavioral response is incorporated into a three-dimensional earthquake–vehicle–bridge dynamic system. Numerical simulations of a biaxial truck passing the Changtai Yangtze River Bridge during an earthquake were conducted. The results indicate that drivers have sufficient time to avoid significant lateral drift when encountering an earthquake while driving on the bridge, and vehicle sideslip and yaw accidents are generally unlikely. Vehicles traveling at lower speeds require more-frequent and pronounced steering corrections, facing a greater risk of sideslip. Higher speeds increase the risk of rollover because of higher centrifugal forces. Vibration parameters related to the vehicle’s roll vibration are the primary factors contributing to the critical state of vehicle rollover. Under large seismic excitation, vehicle speeds have an insignificant impact on rollover accidents. Large earthquakes markedly increase the likelihood of both sideslip and rollover; rollover is more probable than sideslip, and yaw divergence is the least likely to occur.