In the actual context of an aging infrastructure and a clear trend towards ever faster and heavier vehicles, 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 dynamic 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. The present work presents a novel approach for identification of dynamic moving forces acting on a bridge structure. It seeks to find the optimal force values that minimize the difference between the computed and measured displacement and acceleration time histories for a limited number of sensor locations. The experimental investigation of the developed method in relation to real structures in operation indicates that it can be successfully used on a wide range of applications: from small structures excited by rather low pedestrian forces up to the "heavy category" of a complete train passing a railway bridge in operation. The results are very satisfactory, consistently indicating that the proposed method allows a sufficiently accurate identification of the moving forces. In this context, a set of particularities and limitations that arise in the practical the application of the method on real structures are also discussed.weiterlesen