Change of modal parameters of bridge due to vehicle pass

This paper presents an experimental and analytical study investigating the effects of dynamic interaction between a vehicle and a bridge on the dynamic behavior of the bridge, especially on modal properties. On the basis of an ambient vibration test and a vehicle drop test on a bridge, it is found that the natural frequencies of the bridge are changed as a vehicle passes. Parametric studies for the effects of vehicle position, speed, damping, mass ratio and frequency ratio on vehicle-bridge interaction are carried out using a complex eigenvalue analysis and numerical integration. The results show that all vehicle properties except speed can cause significant change of natural frequency and damping of the bridge. It is emphasized that the vehicle is a major source of damping as well as of excitation of the bridge vibration.