Seismic Behavior of Cylindrical Fluid-Filled Steel Tanks

The behavior of cylindrical steel tanks in earthquakes has been documented during post-earthquake reconnaissance dating back to the 1977 San Juan earthquake in Argentina. Observed and documented damage to the tanks has been consistent through the 2014 South Napa earthquake and mainly entails: buckling of tank walls, anchorage failure, damage at locations of connecting piping, and racking of tanks against one another and against catwalk systems. Previous research on the topic has shown that nonlinear evaluation of the tanks is necessary in order to design tanks to withstand seismic demands. However, simplified procedures provided in the American Water Works Association Welded Carbon Steel Tanks for Water Storage (AWWA D100) remain based upon linear methodologies, e.g., elastic limits for lift-off displacements. Nonlinear procedures consider the formation of plastic hinges within the tank and therefore approximate more realistic lift-off displacements of the tank or pull-out forces on the anchorages. Researchers have demonstrated that post-buckling behavior of these tanks is stable and does not result in failure. This paper provides an overview of previous earthquake damage to cylindrical steel tanks used in the wine and water industries, as well as previous research that supports the use of more robust evaluation of these tanks to limit damage and subsequent failure during a seismic event.