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Structural Control: Basic Concepts and Applications

Y. Fujino,

T.T. Soongand B. F. Spencer Jr.

Abstract

Considerable attention has been paid to active structural control research in recentyears, with particular emphasis on alleviation of wind and seismic response. The technology is now at the stage where actual systems have been designed, fabricated and installed in full-scale structures. This tutorial paper presents an overview of some of the basic control concepts as applied to civil engineering structures, provides examples of current fullscale applications of the technology and indicates future directions.

Basic Concepts in Structural Protective Systems

In recent years, innovative means of enhancing structural functionality and safety against natural and man-made hazards have been in various stages of research and development.By and large, they can be grouped into three broad areas: (i) base isolation, (ii)passive damping and (iii) active control. Of the three, base isolation can now be considered a more mature technology with wider applications as compared with the other two(ATC–17 1993).Passive energy dissipation systems encompass a range of materials and devices for enhancing damping, stiffness and strength, and can be used both for natural hazard mitigation and for rehabilitation of aging or deficient structures. In recent years, serious efforts have been undertaken to develop the concept of energy dissipation, or supplemental damping, into a workable technology, and a number of these devices have been installed in structures throughout the world. In general, such systems are characterized by a capability to enhance energy dissipation in the structural systems to which they are installed. This effect may be achieved either by conversion of kinetic energy to heat or by transferring of energy among vibrating modes. The first method includes devices which operate on principles such as frictional sliding, yielding of metals, phase transformation in metals,deformation of viscoelastic solids or fluids and fluid orificing. The latter method includessupplemental oscillators which act as dynamic absorbers.

Among the current passive energy dissipation systems, those based on deformation of viscoelastic polymers and on fluid orificing represent technologies in which the U.S.industry has a worldwide lead.

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March 29, 2009 - Posted by | Uncategorized

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