Variable dampers for semi-active control of a steel-frame structure: a shaking table experimental investigation

A large scale 2-storey steel frame structure provided with a semi-active control system has been experimentally tested at the University of Basilicata (Italy). Two smart bracing systems are installed, each one made up of a chevron-type steel brace, a magnetorheological (MR) damper and a control algorithm, being the latter the logic that in real time drove the behavior of the MR device during the dynamic excitation. Many control algorithms are available in literature aiming at optimally calibrate the MR dampers during the motion according to a different philosophy and/or addressing at achieve a different structural purpose. In the above campaign four different control algorithms were tested, allowing to point out the main differences and to compare the effectiveness (reduction of structural response, energy dissipation capability) and the efficiency (operation errors) they shown, leading to interesting conclusions.