Generalized Beam Theory for the static and dynamic response of a bridge deck with Structural Health Monitoring purposes

In recent years Structural Health Monitoring (SHM) has been assuming a fundamental role for existing bridges and viaducts, primarily for the aged ones, making compelling the need to resort to adequate techniques that enable the user to correctly process and interpret the amount of produced data. In the present work, with the purpose of defining SHM strategies for viaducts, a mechanical model of an existing bridge deck is realized on the basis of the Generalized Beam Theory (GBT). With the aim of catching the static and dynamic behavior of the structure up to prescribed tolerances, the model takes into account, for instance, the possible in-plane and out-of-plane distortion of the cross-sections and, at the same time, turns out to be easy to use and adapt, according to the level of detail one wants to achieve. Possible implementation of geometric and elastic nonlinearities is discussed as well. Moreover, data gained through static loading tests on the bridge, almost up to the elastic limit of the structure, and dynamic tests in operational conditions, processed in the framework of the Operational Modal Analysis (OMA), are used as benchmark for the calibration of the parameters of the mechanical model. A convergence analysis is then performed, so as to define the minimal number of degrees of freedom required to consistently simulate the mechanical behavior of the structure. Discussion on the effects of either point or distributed support conditions is proposed, with consequences in the implementation of the boundary conditions of the mechanical model.