A Semi-active Oleodynamic Damper for Earthquake Control. Part 2: Evaluation of Performance through Shaking Table Tests

Sine sweep and earthquake excitation tests have been performed on a one-story spatial steel frame building equipped with two identical semi-active assemblies described and fully characterized in a companion paper. The tests allowed identifying and validating simple mathematical models of the building in its passive configurations as well as in semi-active operation according to an energy storing and suddenly dissipating algorithm. In order to eliminate or at least attenuate the detrimental effects of control delays due to adopted software, electronic apparatus and mechanical inertia of variable dampers' moving parts, a simple ‘sine-fit’ prediction method was conceived, evaluated and adopted in subsequent tests. It is shown that, with adequate anticipation of device operation, the selected control algorithm produces a satisfactory reduction of building response compared to that obtained in passive configurations, with overall system efficiency practically independent of the earthquake input and related only to the properties of the semi-active assembly.