ABSTRACT
In the actual context of an aging infrastructure, the reassessment of existing bridges becomes an ever more challenging task for civil engineers, especially when crucial decisions regarding costly replacement or rehabilitation measures have to be made. An accurate knowledge of the real forces acting on the structure offers the engineers the possibility of a less conservative but still reliable reassessment process, which can lead to important extensions of the remaining service life and thus to considerable financial benefits for both the bridge owners and the society. However, the direct measurement of moving forces acting on bridges is in most cases either not possible or very cumbersome. On the contrary, time histories of the structural responses can be recorded with reasonable effort. In this sense, this contribution briefly presents a novel approach for identifying a set of moving forces acting on a bridge structure. The inverse problem is solved in the time domain using acceleration and/or displacement time histories recorded at different locations on the structure. Furthermore, a comprehensive experimental validation process performed on a real railway bridge in operation subjected to passages of a high-speed railway vehicle is presented. The results show that the proposed method allows a very accurate identification of the axle loads for a complete railway vehicle with reasonable computational effort.
