PSI - Issue 78

Riccardo Vetturini et al. / Procedia Structural Integrity 78 (2026) 734–744

737

Fig. 3. Extract from UNIPG Report – View of the test setup and displacement transducer placement (left) – Hypothesis of the kinematic mechanism characterizing the dynamic motion of the monumental Ciborium (right)

This effect manifested, in the “as-is” condition, for very small displacements, certainly much lower than those expected from the design earthquake for the site. With a modest forcing, a reduction in the system stiffness was observed, resulting in a natural period of T x = 0.54 sec compared to the previous period of T x = 0.47 sec recorded with microtremors. It was therefore estimated that an even higher natural period would result with an increase in cracking, compared to what was measured with microtremors (assuming a non-partialized column section). 4. Seismic isolation intervention strategy The seismic isolation intervention strategy introduced a sliding plane at the base of the structure (the monument), which allows the Ciborium to be separated from the ground and consequently to decouple the movement of the ground itself from the movement of the superstructure (the sculpture) to be protected. In other words, it acts as a “filter” that reduces the horizontal accelerations induced by the earthquake by up to 8–9 times.