CURRENT STATE OF KNOWLEDGE ON STRUCTURAL CONTROL.

Structures occasionally experience extreme loads, especially during earthquakes or in a high wind environment. Furthermore, it is now becoming possible to deploy large and flexible structures in space. In both cases the response of the structure must be controlled within certain bounds dictated by serviceability. The problem is energy dissipation from or energy input to the structure through external mechanisms. Traditionally, energy has been dissipated through damping. Passive control devices have been used that basically supplement the damping characteristics of a structure. Semi-active and active control devices have recently been introduced. They promise a more efficient use of the resources available for control and improved accuracy in controlling the response of a structure.