ABSTRACT
This chapter deals with interactions between the plant and the underlying soil region. The design ground motion is defined at the surface and far from the buildings in order to distinguish how it is defined from how it is filtered through the soil-structure model and the structure-system/component models. The seismic response of the structures, systems, and components of the plant can be obtained with two different techniques of analysis: dynamic methods and pseudo-static methods. Geotechnical investigations are required in order to know the medium, which has been assigned to receive and transfer loads from and to the structures. Geotechnical investigations have to be carried on, during the construction stage of the plant, setting up geotechnical instrumentation, in order to collect further data about the soil behavior and review, if necessary, the design specification related to the foundation soil. The peak values of the transfer function correspond to the natural frequencies of the soil deposit.
