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Performance assessment of the KDamper as a seismic Absorption Base

The KDamper is a novel passive vibration absorption concept based essentially on the optimal combination of appropriate stiffness elements, one of which has a negative value. In this paper, the implementation of the KDamper as a seismic Absorption Base (KDAB) is considered. The performance of the KDAB is assessed in three characteristic test cases, namely, a rigid body and two flexible buildings with fundamental periods of 0.5 and 1.0 s, respectively. In all three cases, the structures are excited by real and artificial accelerograms. The performance of the KDAB is compared not only with the original structure but also with the cases of conventional and highly damped base isolation systems, as well as with the case of a tuned mass damper inerter. Alternative options for the selection of the KDamper nominal frequency are considered, leading to two cases. In the first one, the nominal KDamper frequency is selected equal to the low frequency of a conventional base isolation system, resulting in a drastic improvement of the overall structural performance (i.e., superstructure accelerations and base drifts). In the second one, the KDAB is implemented with a much higher nominal frequency, leading to a drastic reduction of the relative base displacement, in the order of few centimeters, combined with acceptable structural performance. As a consequence, the KDamper can be implemented as a supplement of a conventional base isolation system or, alternatively, as a “stiff absorption base,” overcoming the disadvantages of seismic isolation approaches, leading towards new seismic protection technologies.