The Use of the Forced Frequency of a Bridge Due to a Truck Fleet for Estimating Stiffness Losses at Low Speed

The influence of traffic loads on the dynamic features a bridge is an external factor that can hinder true condition structure. This paper aims to effectuate shift in way this viewed. If interaction between vehicle and modeled using finite element method, response based mass, stiffness, damping matrices coupled vehicle-bridge system vary with location load at each point time. time-varying forced frequencies beam model due fleet 3-axle trucks eigenvalue analysis (i.e., derived from system) are compared those obtained transient frequency content acceleration truck crossing). Truck properties randomly varied within realistic range obtain pattern for vibration traveling ideal speed 1 m/s 15 m smooth surface, 10 30 bridge. These patterns reveal trend allows locating quantifying stiffness loss associated crack only frequency. implementation methodology requires installation accelerometers bridge, nearby weigh-in-motion identify interest. High requirements resolution limit application bridges located low routes.