Bridge Vibration Under Vehicular Loads: Tire Patch Contact Versus Point Contact

When establishing the equations of motion of the bridge-vehicle coupling system, most researchers simplify the contact between the vehicle tire and road surface as a point contact. In reality, a vehicle tire deforms and makes contact with the road surface over a footprint area called patch contact. This paper presents a new method that allows for the effect of the patch contact on the dynamic response of the bridge-vehicle coupling system. In this method, the vehicle tire is modeled as a two-dimensional elementary spring model, and the patch contact is assumed to be a rectangle. The bridge-vehicle coupling equations are established by combining the equations of motion of both the bridge and vehicle using the displacement relationship and interaction force relationship at the patch contact. A series of simulation studies have been carried out in which the effects of various factors such as vehicle speed, tire stiffness and damping, size of the patch contact, number of vehicles, and faulting condition have been investigated. The numerical simulations and field test results show that the proposed method can more rationally simulate the interaction between the bridge and vehicles.