Identification of parameters of vehicles moving on bridges

This paper presents a method for identifying the parameters of vehicles moving on bridges. Two vehicle models, a single-degree-of-freedom model and a full-scale vehicle model, are used. The vehicle–bridge coupling equations are established by combining the equations of motion of both the bridge and the vehicle using the displacement relationship and the interaction force relationship at the contact point. Bridge responses including displacement, acceleration, and strain are used in the identification process. The parameters of vehicles moving on the bridge are then identified by optimizing an objective function, which is built up using the residual between the measured response time history and predicted response time history using the Genetic Algorithm. A series of case studies have been carried out and the identified results demonstrate that the proposed method is able to identify vehicle parameters very accurately. Field tests have also been performed on an existing bridge in Louisiana, and the parameters of a real truck are predicted. Since it is able to identify the parameters of moving vehicles, the methodology can be applied to improve the current weigh-in-motion techniques that usually require a smooth road surface and slow vehicle movement to minimize the dynamic effects. The methodology can also be implemented in routine traffic monitoring and control.