Identification of multi-axle vehicle loads on beam type bridge based on minimal residual norm steepest descent method

Moving force identification (MFI) from dynamic responses of bridges is a typical inverse problem in the field of structural dynamics. To deal with the difficulties in identifying multi-axle vehicle loads caused by the interference of adjacent axle loads, a novel minimal residual norm steepest descent method (MRNSD) is proposed. Firstly, the identification accuracy and noise insensitivity of the new method is verified by identifying two-axle vehicle with different speeds. Secondly, the influence of impact force and vehicle wheelbase is investigated to illustrate the applicability of the proposed method. Then, the effectiveness of the MRNSD method is verified by identifying several different types of multi-axle vehicles. Finally, experimental studies are conducted to further validate the effectiveness of the MRNSD method. Numerical simulation and experimental studies show that the MRNSD method has high identification accuracy and strong robustness in different force identification cases. With these advantages, the proposed method provides a favorable choice for force identification in practice.