Effect of approach span condition on vehicle-induced dynamic response of slab-on-girder road bridges

The present study investigates the effect of approach span conditions on a bridge’s dynamic response induced by moving vehicles. After developing a 3D bridge–vehicle interaction model for numerical prediction, a dynamic test on a full scale slab-on-girder bridge is conducted with dump trucks to validate the developed numerical methodology. A wooden plank is used to simulate the large faulting between the bridge deck and the approach slab. With consideration of the road surface profile and approach span condition, the predicted dynamic response of the bridge is compared to the experimental results, and they show a satisfactory agreement. The numerical model is also applied to investigate the effect of the approach span condition on the dynamic behavior of the bridge induced by the AASHTO HS20 truck. A parametric study is eventually conducted by changing the road surface condition and the faulting value. The faulting condition of the approach span is found to cause significant dynamic responses for the slab-on-girder bridges and to have a considerable effect on the distribution of impact factors along the transverse and longitudinal directions. Furthermore, impact factors obtained from the numerical analyses are compared with those values specified in the AASHTO codes.