Seismic Design of Elevated Steel Tanks with Concentrically Braced Supporting Frames

The presented work deals with the seismic design and response evaluation of elevated steel containment tanks. The focus of the paper is on the behaviour of the supporting structure, since a horizontal ground motion will mainly cause damage to this part of the overall structural system. A case study has been considered, where, according to common practice, the supporting structure is a steel concentrically braced frame. In both design and response evaluation processes, particular attention has been paid to the consideration of internal fluid sloshing phenomena and on their implication on the overall dynamic response of the system. Two design methods have been considered: one in accordance with the relevant international codes and a second proposed method that allows considering the strength of braces in compression. The dynamic response of the elevated tank has been evaluated through linear and non-linear analysis. The different analysis strategies considered are compared and the influence of the design process on the global response is highlighted.