Analysis of Pressurized Horizontal Vessels under Seismic Excitation

Codes for design and constructions of pressure-vessel provide a number of loading conditions that have to be considered. Pressures are primary loadings that are applied either internally or externally over the surface of the vessels; applied forces act either at local points or throughout the mass of the vessel. Among applied loads, inertial forces due to ground motion can be relevant when industrial plants located in seismic areas are of concern. In fact, earthquake represents external hazard that interacts with safety of industrial equipments and systems. It can trigger accidental scenarios as fires, explosion and dispersion of toxic substances from industrial equipment, thus increasing the damages to people, environment and properties. In this context, dynamic behaviour of industrial equipment, as for example pressurized horizontal cylinders, is certainly of interest. An assessment of available technical solutions and design guidelines concerning pressurized equipments has been carried out. This preliminary stage of the work leads to a structural standardisation of components and detailing able to cover the need of knowledge for seismic risk evaluations. The present paper tackles from a structural and seismic engineering perspective, the assessment of seismic performances of pressurised vessels. Dynamic analyses of vessels designed according to National and International Codes are discussed and relevant outcomes for seismic protection of components are highlighted.