AbstractThe present study proposes vector-valued intensity measures (IMs), consisting of two IM parameters, for improved and efficient seismic risk assessment of liquid storage tanks base isolated with laminated rubber bearing (LRB) and lead rubber bearing or New Zealand base-isolation system (NZ system). To assess the seismic risk of the base-isolated liquid storage tanks, their seismic fragility was obtained using stripe analysis. The joint hazard of the selected IMs was obtained using vector-valued probabilistic seismic hazard analysis. It is shown that the vector-valued intensity measure consisting of peak ground acceleration (PGA) and spectral acceleration (Sa) at the isolation period (Tb) is efficient for predicting the peak base shear demand in the liquid storage tanks base isolated with LRB. Similarly, the vector-valued intensity measure consisting of PGA and peak ground velocity (PGV) is efficient for predicting the peak base shear in the liquid storage tanks base isolated with the NZ system. This study also presents parametric investigations on the effect of thicknesses of the tank wall (tw) and the slenderness ratio (S) of the tank on the seismic risk of the base-isolated liquid storage tanks.Practical ApplicationsThe societal and industrial importance of liquid storage tanks is well understood, and it is necessary to ensure their safety during a strong earthquake for conducting post-earthquake response operations as well as to avoid any cascading hazardous event. To mitigate the seismic risk to a tank structure, the use of base-isolation technique, which minimizes the transmission of seismic force to the structure from the ground, is increasing worldwide. However, one can implement appropriate mitigation measures only when the associated seismic risk is quantified after understanding the prevailing seismic hazard and response of the structure under the expected level of earthquake. In the context of performance-based earthquake engineering, the seismic risk to a structure is assessed using key parameters such as IMs and engineering demand parameters (EDPs). Nevertheless, the choice of efficient IMs is always a challenge to estimate the probable seismic risk to a structure. This study proposes efficient vector-valued IMs for seismic risk assessment of base-isolated liquid storage tanks. The presented results can be used for efficient assessment of seismic risk for existing, and during the designing phase of newly proposed, base-isolated liquid storage tanks.