Improving the seismic performance of base-isolated liquid storage tanks with supplemental linear viscous dampers

Large tanks are extensively used for storing water, petrochemicals and fuels. Since they are often cited in earthquake-prone areas, the safe and continuous operation of these important structures must be ensured even when severe earthquakes occur, since their failure could have devastating financial and socio-environmental consequences. Base-isolation has been widely adopted for the efficient seismic protection of such critical facilities. However, base-isolated tanks can be located relatively close to active faults that generate strong excitations with special characteristics. Consequently, viscous dampers can be incorporated into the isolation system to reduce excessive displacement demands and to avoid overconservative isolator design. Nonetheless, only a few studies have focused on the investigation of seismic response of base-isolated liquid storage tanks in conjunction with supplemental viscous dampers. Therefore, the impact of the addition of supplemental linear viscous dampers on the seismic performance of tanks isolated by single friction pendulum devices is investigated herein. Four levels of supplemental damping are assessed and compared with respect to isolators’ displacement capacity and accelerations that are transferred to the tanks.