Seismic protection of buildings of historical/cultural interest through the use of vibrating barriers.

Recent earthquake events pointed out the problematic of protecting existing buildings from the catastrophic effects of earthquakes. The current strategies for vibration are successfully employed in the design of new structures; on the other hand, they are rarely used for protecting existing buildings, because they generally require substantial alteration of the original structure. In this thesis, a novel device called vibrating barrier, (ViBa), is implemented for the seismic protection of an historical building: the Bell Tower of the Messina Cathedral. This device is able to reduce the dynamic response of a target building without being physically connected to it. The dynamic behaviour of the system has been studied through the construction of a detailed FE Model that allowed to derive the response of the structure and to study the existing influences between the buildings and the effect of the soil. Hence, a simplified mathematical model has been constructed, and the pertinent parameters have been computed by the employment of an Identification Process. Moreover, the mechanical parameters of the ViBa have been derived through an Optimization Process in order to reduce a selected response parameter of the bell tower, under an input ground motion modelled as Gaussian Stochastic Process compatible with the Messina response spectrum. Hence, parametric analyses have been carried out in order to investigate the influence of the mass of the device on the efficiency. Spectrum-compatible artificial accelerograms have been generated and a significant average reduction of the maximum displacements of 25% has been achieved, together with a decrease of 40% of the shear forces in the bell tower. Due to large masses involved, alternative solutions have been proposed against the problems related to a real-life implementation of the device, and the beneficial effects given by the coupling of the ViBa with a set of mechanical inerters have been demonstrated.