A State Space Formulation for Moving Loads Identification

A new moving load identification method formulated in state space with regularization on the solution is presented. The bridge deck is modeled as an orthotropic rectangular plate, and the loads are modeled as a group of loads moving on top of the bridge deck at a fixed distance and at a constant speed. The Hamilton principle and the modal superposition principle are included in the formulation. Numerical simulations and experimental tests are employed for the verification and illustration on the effectiveness of the proposed method. The effects of different sensor location, different load path eccentricity, different types of measured information, and measurement noise have been investigated, and the effect of the aspect ratio of the bridge deck is also studied. It is concluded that nine sensors collecting information from nine vibration modes would give reasonably accurate identified results over the practical range of aspect ratio of a modern bridge deck. Acceleration responses are preferred over the velocity and strain responses in this study, and the same type of response should be collected for the same supporting beam in the longitudinal direction.