Smart seismic rocking motion control of fluid tanks using semi-active model-based and data-driven adaptive control

Various mechanisms have been investigated in the literature for seismic protection of fluid tanks. These structures play a pivotal role in the integrity, reliability, and safety of strategic industries. Any damage to fluid tanks can jeopardise these industries and the environment. In this research, a Smart Vertical Isolation System using magnetorheological dampers for rocking isolation of legged rigid cylindrical fluid tanks under base excitations has been proposed and investigated. First, dynamic equations of motion for the rocking rigid fluid tank are developed. Different semi-active classical and an online data-driven adaptive control technique are then employed to examine the efficacy of the rocking isolation system. Parameters of the data-driven controller are estimated online in real-time using the Recursive Least Squares approach, which offers simplicity, robustness against faults, and small memory requirements. Numerical simulations are compared with experimental investigations to validate the accuracy of the developed dynamic equations and the performance of the MR dampers and control techniques in mitigating the seismic effects on the examined fluid tank. The MR dampers and semi-active control strategies proved substantial reductions in the uplift displacement of the tank as one of the main causes of damage to these structures under earthquakes.