Seismic study of flexible rectangular containers isolated by different outstanding isolation systems

Concrete fluid storage containers have been important elements in the industrial facilities, so that grounded rectangular types of this structure are widely used for the long-term storage of nuclear spent fuel assemblies. Significant numbers of previous studies have been done on the seismic analysis of fluid containers but a few of which have been studied on the seismic responses of flexible rectangular containers with base isolation systems. Therofore, the seismic behavior of base-isolated flexible rectangular fluid storage containers is investigated and to measure the effectiveness of the seismic isolation, the seismic responses of isolated containers is also compared with non-isolated type in present study. An equivalent mechanical model of rectangular tanks is used which contains three lumped masses known as: convective mass, flexible mass and basic mass. Eventually, results were shown that seismic base isolation systems can be an effective manner to reduce seismic responses, such as base shear and hydrodynamic pressure, but usage of this technology found to have adverse or/and neutral effects on the sloshing height. An increase in displacements for all isolation systems in horizontally isolated tanks seems to be inevitable and this factor increase as the isolator becomes more flexible.

Keywords:

Rectangular Containers , Seismic Isolation , Mechanical Model , Hydrodynamic pressure , Sloshing Height