1:4 Scale Model Studies of Active Tendon Systems and Active Mass Dampers for Aseismic Protection

Keywords: Active Tendon Systems (ATS), Active Mass Dampers (AMD), Tuned Mass Dampers (TMD), Earthquake Resistant Design, Active Control Systems, Protective Systems, and Structural Engineering.

Abstract: The comprehensive reviews of active structural control have shown that among the most prominent devices for the control of structures during transient disturbances are the active tendon system (ATS), and the active mass damper (AMD). The ATS uses either prestressed cables or diagonal bracings which can be activated axially by servo-controlled hydraulic or electromagnetic actuators. Extensive analyses showed that the active tendon system provides a feasible solution in reducing the vibrations of slender structures, tall buildings, cable stayed bridges, and off-shore structures. The AMD is a derivation of passive devices, which are presently used in several tall building structures for motion control during strong winds. A large mass, placed on an upper story of a building, is connected to the structure via actuators or springs, and is free to slide on a smooth surface. A hydraulic power source moves the mass which in turn transmits forces to the structure which reduce structural vibrations. Since 1982, a comprehensive experimental study has been designed and carried out by the first two authors and their associates to study the feasibility of active tendon control, using a series of carefully calibrated structural models. As a further step, a substantially larger and heavier six-story model structure was fabricated for stage 3 of the experiment and was used for a simultaneous experimental and analytical study of ATS and AMD controls.