Seismic Control of the Phase II Base Isolated Benchmark Problem by A Proposed Semi-Active Algorithm

Performance of a proposed semi-active control algorithm is investigated during the seismic control of a base isolated ۸-storey benchmark building. The building, which is equipped by nonlinear isolators, has been developed by other researchers to evaluate the performance of various control algorithms in MATLAB® and SIMULINK®. The proposed algorithm creates an artificial nonlinear damping force, so that the base shear hysteresis curve show a high energy dissipation capability while limiting the maximum base shear. The idea is taken from the hysteresis curve generated by friction bearings and modifications were made to reduce the demerits while keeping the merits of this type of isolators. A numerical model of a MR damper is employed in the analysis. To compare the results, a passive viscous damping system, as well as a variable damping system controlled by skyhook algorithm is utilized. Seven pairs of earthquakes provided by the developers of the benchmark problem are used for the time history analysis. The resulted base-shear hysteresis curves are presented for the three studied cases. The comparison of the performance indices indicates that the employed semi-active control methods have better performance than the passive method. The base displacement values are mostly less in the model controlled by the proposed algorithm. However, it resulted in larger floor accelerations, which is originated by the sudden changes in the damping force.