Studies performed in Italy for Seismic Isolation of Chemical Plant Components

Reported in this paper are the main features and first results of a study which was undertaken in Italy in 1999 for checking the applicability of seismic isolation (SI) systems to chemical plant components, evaluating both the benefits of such systems on plant safety and their effects on plant lay-out and construction costs, and developing the most suitable systems, in terms of combinations of isolation, dissipative and friction devices. The study should lead to the first pilot application of SI to a chemical plant component in Italy, in view of a future much more extensive use of this technique in this field. The selected component is an existing spherical butane storage tank, which may be retrofitted using SI at the conclusion of the study. Numerical models of such a component have been developed, together with suitable ground acceleration time-histories, specific of its site. The main features of the SI system have been provisionally defined and dynamic analyses have been performed to design the SI system in detail, evaluate its benefits and if necessary, improve or modify the assumed system features.