Structural assessment of bridges and health monitoring programs based on dynamical tests

The assessment of the structural conditions of bridges is dealt with in this work. Usually the bridge conditions are analysed by means of visual inspections and standard controlling procedures. In this work the use of systematic dynamical tests is proposed as indispensable mean to correctly quantify, by means of a consistent FE model, the level of maintenance. Moreover the proposed path is the only one acceptable when structural modifications are needed to improve the performance of the structure under certain loading conditions (moving loads, earthquake, and so on). Among a series of analysed bridges, two case studies will be presented: the first is concerned with identification and damage assessment of an artificially damaged bridge, while the second is concerned with the estimation of the seismic performances of a bridge after the execution of restoration works. The two case studies are used to enlighten and discuss the wide range of effective applicability of dynamical tests in SHM programs.