Definition of seismic input for structures and installations

While the characterisation of basic seismicity in terms of response spectra (or, in the case of particularly important plants, in the form of sets of spectrum-compatible accelerograms) is indispensable, it is not sufficient to define the actions on the entire structure-plant system. Non-structural elements and installations are subject to different seismic actions to those on the ground because they are significantly modified and amplified by the structure. In order to design plant components and their connections adequately, it is necessary to define the seismic actions at floor level or, more generally, at the point of installation. Depending on the component type and its connection to the structure, the actions must be determined in terms of accelerations and/or displacements. In the case of Major Accident Hazard Installations (RIR), all effects caused by relative displacements that may result in leakage or spillage of the treated materials cannot be neglected for safety assessment purposes.

For years, the staff at Fondazione Eucentre have been carrying out numerical and experimental research in this field, dealing with the analysis of structures to define plane spectra, evaluating the local response of individual components, and conducting experiments on entire structures, non-structural elements, and plants.