Moving load identification on a simply supported orthotropic plate

Different aspects of dynamic identification of moving loads from a vehicle traveling on top of a beam-slab type bridge deck are studied in this paper. The bridge deck is modeled as an orthotropic plate and the loads are modeled as a group of wheel loads or a group of axle loads moving on top of the bridge deck at a fixed spacing. The dynamic response of the bridge deck is obtained from the Hamilton principle with modal superposition. The equation of motion is formulated in state space and the resulting damped least-square identification problem is solved using the dynamic programming method with regularization on the solution. The combination of dynamic strain and velocity measurements, the number of analytical modes included in the identification, the effect of load eccentricity and the choice of regularization parameter are studied and discussed. The use of separate regularization parameter for each of these loads has been implemented and discussed. These considerations are further studied with experimental results from the laboratory. Recommendations on the selection of sensor number and sensor locations for moving loads identification are given.