Adaptive base-isolation of civil structures using variable amplification
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Kenneth K. Walsh and Makola M. Abdullah
Department of Civil and Environmental Engineering, FAMU-FSU College of
Engineering, Tallahassee, FL, 32310, USA
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Abstract: Semi-active dampers are used in
base-isolation to reduce the seismic response of civil engineering structures.
In the present study, a new semi-active damping system using variable
amplification will be investigated for adaptive base-isolation. It uses a novel
variable amplification device (VAD) connected in series with a passive damper.
The VAD is capable of producing multiple amplification factors, each
corresponding to a different amplification state. Forces from the damper are
amplified to the structure according to the current amplification state, which
is selected via a semi-active control algorithm specifically tailored to the
system¡¯s unique damping characteristics. To demonstrate the effectiveness of the
VAD-damper system for adaptive base-isolation, numerical simulations are
conducted for three and seven-story base-isolated buildings subject to both far
and near-field ground motions. The results indicate that the system can achieve
significant reductions in response compared to the base-isolated buildings with
no damper. The proposed system is also found to perform well compared to a
typical semi-active damper.
Keywords: adaptive systems; amplification;
base-isolation; damping; earthquake resistant structures; multistory buildings;
seismic isolation; structural control
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