Updating of analytical models of existing large structures based on modal testing

The state-of-the-art of experimental structural dynamic's investigations and of Finite Element model updating based on such experimental results as well as the purpose of such investigations are discussed and illustrated. Firstly, experimental methods to determine the dynamic properties of existing civil engineering structures are described. The methods presented are Forced Vibration Testing and Ambient Vibration Testing. It is the goal of both methods to evaluate the structure's modal parameters which reflect the structure's actual static and dynamic boundary conditions and its stiffness and mass properties. Advantages and disadvantages of the two experimental methods as well as the capabilities and inherent problems of Finite Element model updating based on the results of such tests are then discussed. Finally, these considerations of more theoretical nature, but based on long-term experience, are illustrated with describing investigations performed on six bridges and a dam. It is the goal of this paper to present modern methods of evaluation of existing structures and to provide advice of how to optimally make use of them.