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

Abstract

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.

Towards probabilistic seismic performance of vehicle‐bridge interaction systems: From stochastic dynamic model to fragility analysis

“…Meanwhile, the vertical displacement of the deck is also paid substantial attention in the previous studies on the behavior of the VBI system. 8,10 To this end, this study selects the pier drifts of pier P1 (transitional pier) and pier P4 (middle pier), the shear strain of bearing B1 and bearing B5, along with the vertical deck displacement at point A (see Figure 5A and B, hereafter called deck displacement) as the focused EDPs. Moreover, the average spectral acceleration (AvgSa), which has won widespread recognition as one of the state-of-the-art optimal IMs, 66,67 is employed for the fragility analyses of the VBI system.…”

“…For the seismic performance assessment of bridges, the translational bearing deformation and pier flexural deformation are usually examined. Meanwhile, the vertical displacement of the deck is also paid substantial attention in the previous studies on the behavior of the VBI system 8,10 . To this end, this study selects the pier drifts of pier P1 (transitional pier) and pier P4 (middle pier), the shear strain of bearing B1 and bearing B5, along with the vertical deck displacement at point A (see Figure 5A and B, hereafter called deck displacement) as the focused EDPs.…”

“…Results indicated that the number and the position of moving vehicles, as well as the relative distance between them, are dominant factors. 8 Cui et al 9,10 interpreted the mechanism of the VBI system under seismic excitations from the viewpoint of energy analysis and revealed that the mass ratio of the vehicle to bridge is one of the primary factors affecting the seismic performance of bridges. Additionally, Borjigin et al 11 put forward a seismic performance assessment framework incorporating the VBI with inelastic dynamic analysis, and the results indicated that neglecting the effect of vehicles may yield an unconservative evaluation.…”

“…Results indicated that the number and the position of moving vehicles, as well as the relative distance between them, are dominant factors 8 . Cui et al 9,10 . interpreted the mechanism of the VBI system under seismic excitations from the viewpoint of energy analysis and revealed that the mass ratio of the vehicle to bridge is one of the primary factors affecting the seismic performance of bridges.…”

Simplification of earthquake induced vehicle bridge interaction contact simulation for urban viaducts

“…However, the nonlinear Hertz model is inconvenient to be incorporated by commercial software and lacks universality and efficiency in comprehensive numerical simulations of more real scenarios of parking vehicles and complex bridge structures. In addition, the vertical contact force will affect the calculation of horizontal vehicle‐bridge frictions, 8 so that the VBI system needs to solve the complex nonlinear vertical‐horizontal coupling equations in advance to get the vehicle's horizontal responses, causing the risk of divergence of solving kinetic equilibrium equations of VBI system. Therefore, some scholars have proposed simplified models which can consider the separation of vehicles and bridges 16–18 .…”