Identification of Axle Spacing and Axle Loads of Moving Truck Using Dynamic Bridge Response

A methodology of axle loads identification of a moving truck using bridge responses with free of axle detection is presented. Based on the inverse problem, the static axle loads and axle spacing are firstly estimated using least squares optimisation with respect to the relationship between bridge responses and moving point loads. Dynamic axle loads are secondly identified by employing the previously obtained static axle loads and axle spacing as the initial guess in the optimisation. Regularisation technique is utilised in the calculation for higher robustness and solution accuracy. From a parametric study conducted in computer simulation, effectiveness of the proposed method is evaluated. The proposed method is effective to identify dynamic axle loads of the truck, particularly in the time history of the total load. Axle spacing and distribution of axle loads significantly influence to the accuracy of both static and dynamic loads identification. Recommendation for system implementation is also given.