Mechanism study of vehicle-bridge dynamic interaction under earthquake ground motion

With increasing traffic congestion happening across the world nowadays in the busy highway bridge systems and urban areas, seismic interaction between vehicle and bridge is a subject that has attracted increasing research interests. A few studies were conducted in recent years. There seems to be a cursory consensus that the behavior of vehicle is similar to a tuned-mass-damper and usually results in beneficial effect to bridge seismic responses. However, the mechanism of seismic interaction between vehicle and bridge still remains unclear. Present study statistically investigates the seismic responses of both vehicle and bridge under real earthquakes and a reasonable explanation as to the interaction mechanism between vehicle and bridge is given based on energy analysis. The results show that dynamic interaction would affect the energy distribution between vehicle and bridge. Vehicle has little influence on seismic responses of bridge in the horizontal directions because of the change of energy imparted to bridge caused by vehicle is very small. On the contrary, vehicle responses in the horizontal directions, under some circumstances, are extremely large as a result of relatively large energy imparted from bridge to vehicle. In the vertical direction, a surge of energy imparted to bridge, at some instant of time, caused by vertical compression force between vehicle and bridge could result in significant increases in peak responses of bridge. However, the total input energy imparted to bridge over the duration of earthquake is reduced lessening the overall damage of bridge. © 2021 John Wiley & Sons Ltd.