Experimental Study of Active Control of MDOF Structures Under Seismic Excitation

Keywords: Active Structural Control, Structural Control, Shaking Table Test, and Instantaneous Optimal Control.

Abstract: Active control of building structures has been extensively studied theoretically using a variety of control schemes showing varying degrees of efficiency. The demand for experimental evidence of feasibility of control of structures subjected to severe transient loads led to the present study. Structural control experiments were carried out in the laboratory using a 1:4 scaled model structure simulating a three-story frame building. The control experiments were performed using a system of prestressing tendons connected to a servo-hydraulic system and linear optimal control algorithms. The model was subjected to base motions produced by a 12' by 12' shaking table, which included banded white noise and earthquake accelerograms. Results of the experiments show clearly that traditional algorithms can be implemented when proper adjustments are made. These include compensations for time delay and error accumulation in the online computation. Several new algorithms based on instantaneous optimal control were experimentally verified in this study, following new developments based on previous experiments involving single-degree-of-freedom structures. The efficiency of various algorithms is discussed along with comparisons of analytical and experimental results.