Active structural control by varying boundary strain condition between two different structural components

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A new siructural design concept applying active control techniques is presented. Its distinctive feature is the unique control forces which are supplied by the strain between different kinds of lateral resistant structural components such as concrete walls, diagonal bracings, rigid frames and so on. Substantial strains may be -generated along their boundary during lateral loadings associated with earthquakes. Springs installed at the boundary between these two different components can generate control forces proportional to the strain and Their stiffnesses. When the stiffness is made to vary in accordance with a certain rule, the generated force may be used for active control. Sliding mode control theory is discussed in detail as it applies to problems concerning : the optimum switching surfaces, the range of stiffness required to reach the sliding mode, practical control laws approximately satisfying Liapnov stability criterion under external disturbances. These problems are clarified in a more concrete way in the following computer simulation analyses using 1-degree-of-freedom system(1997) and 2-degree-of-freedomsystem(1998). Miniature model s of These systems were built and experimental studies are also carried out to confirm the performance of This active structural design concept in practice where manufacturing tolerance errors, time delays in data processing, characteristics of dynamic responses, random mechanical or electrical disturbance must be allowed for. The test result shows that This scheme offers a possibility of using active structural control as a practical means to combat severe earthquakes.