Experimental Verification of Multiinput Seismic Control Strategies for Smart Dampers

This paper documents the results of an experimental study conducted to demonstrate the capabilities of multiple magnetorheological (MR) devices for seismic control of civil engineering structures. A six-story test structure in the Washington University Structural Control and Earthquake Engineering Lab is considered, and four parallel-plate, shear-mode MR dampers are used to control this test structure. Two control devices are installed in the test structure between the base and first floor, and two are installed between the first floor and second floor. A phenomenological model of the shear mode MR damper is proposed and verified. A nonlinear system identification method, appropriate for multi-input/multi-output systems, is used to develop a model of the integrated structural system. Experimental transfer function data corresponding to one system input are used to update the eigenvalues of an analytical model. Two semiactive control algorithms, including a Lyapunov algorithm and a clipped-optimal algorithm, are considered. An El Centro earthquake example is used to disturb the system at three amplitude levels. The results indicate that high performance levels can be achieved, and the responses of the semiactive system are significantly better than that of comparable passive systems.