Seismic control of civil structures utilizing semi-active MR bracing systems

Magnetorheological (MR) dampers are a promising class of devices for the control of civil structures for earthquake hazard mitigation. MR dampers exhibit both viscous damping and friction damping, where the friction damping level is controlled by an applied magnetic field. This unique characteristic, as well as low power requirements, high force capacity, and mechanical simplicity, lends them to be very suitable devices for the semi-active control of such seismically loaded structures. This study investigates semi-active control methods and their application to MR dampers. Skyhook control and a "clipped" Continuous Sliding Mode (CSM) control are simulated both numerically and experimentally The results show that control of civil structures with semi-actively controlled MR braces is very effective.