Seismic response mitigation of elevated tanks by HDRB and FPS isolation systems

The aim of the paper is to evaluate the effectiveness of two isolation systems for the seismic protection of elevated steel storage tanks: High Damping Rubber Bearings (HDRB) and Friction Pendulum (FPS) isolators. As a case study, an elevated tank which collapsed during the Kocaeli Earthquake in 1999 at Habas Pharmaceutics plant in Turkey has been studied. A time-history analysis is conducted using lumped mass model to demonstrate the high base shear demand and inevitable collapse of support columns due to the insufficient shear strength. A proper design of HDRB and FPS isolator and a complete non-linear analysis of the isolated tanks prove the high effectiveness of both isolation systems for reducing the response of the tank. Results revealed that the tank with the FPS provides better performance compared to HDRB in terms of the isolation displacement convective base shear demands.