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Yayın Behavior of base-isolated liquid storage tanks with viscous dampers under historical earthquakes considering superstructure flexibility(Turkish Journal of Civil Engineering, 2023) Güler, Elif; Alhan, CenkLiquid storage tanks (LSTs) can be efficiently protected from far-fault earthquakes by baseisolation. However, large isolation system and sloshing displacements may threaten the tank’s safety under near-fault earthquakes. Although the application of supplemental viscous dampers (VDs) at the base-isolation systems of LSTs located in near-fault areas may help, it may also increase superstructure demands under far-fault earthquakes. In addition to the characteristics of the earthquake, the isolation system and the superstructure properties may affect the success of base-isolated LSTs with supplemental VDs. Therefore, a numerical investigation is conducted in this study in order to determine the influence of the supplemental viscous damping ratio, the isolation system period, the tank wall flexibility, and the tank slenderness ratio on the seismic responses of base-isolated cylindrical steel LSTs with supplemental VDs including the base displacement, the sloshing displacement, and the normalized isolation system shear force under both near-fault and far-fault historical earthquake records. The tank is modeled by single-degree-of-freedom systems representing different modes on a common isolation basemat and the nonlinear dynamic analyses are carried out in 3D-BASIS-ME software. Findings show that while supplemental damping is required especially when LSTs with long-period isolation systems are subjected to large magnitude near-fault earthquakes, it may also cause amplifications in the sloshing displacement and isolation system shear force demands in case of far-fault earthquakes. Furthermore, it is determined that the influence of tank flexibility on both the superstructure and the isolation system responses is negligibly small while the tank slenderness ratio may have considerable effects.Yayın Performance limits of base-isolated liquid storage tanks with/without supplemental dampers under near-fault earthquakes(Elsevier Science Inc, 2021) Güler, Elif; Alhan, CenkIn order to ensure the continuity of the production process and avoid health, security, and ecological problems, the protection of the liquid storage tanks (LSTs) in industrial complexes against earthquakes is vital. Although base-isolation is successful in protecting LSTs from the detrimental effects of far-fault earthquakes, it is challenged by large-amplitude and long-period velocity pulses observed in near-fault earthquakes which may cause large isolator and sloshing displacements. Employing supplemental damping in the isolation system may reduce isolator displacements but the improvement in the superstructure response may be limited if not worsened. Thus, determining the performance limits of base-isolated LSTs with/without supplemental damping in terms of both isolation system and superstructure responses through a systematic examination considering different levels of earthquake magnitude and different fault distances is essential. Since the period and the amplitude of the ground velocity pulse is dependent on the earthquake magnitude and the closest fault distance, such an examination will also help reveal the influence of the characteristic properties of near-fault pulses on the responses of these structures. Therefore, here, a benchmark LST with different base-isolation systems with/without supplemental viscous dampers, located at different fault distances are subjected to synthetically generated near-fault earthquake records with different levels of moment magnitudes. Various isolator and viscous damper characteristics are taken into account. Non-linear time history analyses are conducted to obtain isolator displacement, sloshing displacement, and isolation system shear force responses and the performance limits of the benchmark LST with different base-isolation systems with/without supplemental dampers are presented in a comparative manner.