EXPERIMENTS ON ACTIVE CONTROL OF SEISMIC STRUCTURES.

This paper presents the first phase of a comprehensive experimental study concerning the possible application of active control to structures under seismic excitations. In the laboratory, a single-degree-of-freedom model structure was used which was controlled using prestressing tendons connected to a servohydraulic actuator. An optimal closed-loop control scheme using a quadratic performance index was employed to reduce the response of structure under base motion generated by a large-scale seismic simulator. The time delay between the observed motion and the implemented control forces, an important factor in control implementation, was integrated in the control algorithm. Using a carefully designed, fabricated, and calibrated experimental setup, the correlation between the analytical and experimental results was studied.