Tuned mass dampers for the mitigation of impulsive ground motions

The performance of tuned mass dampers (TMDs) diminishes as the input duration shortens. As a result, they are not recommended for use against short-duration, pulse-like ground motions, such as those occurring in near-field (NF) zones in the presence of forward-directivity or fling-step effects. Yet a systematic assessment of this control loss is still missing. In this paper, a recent analytical model of ground motion pulses is applied to the design and evaluation of TMDs against impulsive earthquakes. Based on this model, first a new optimization method is introduced as an alternative to the classical H∞ approach. Then the two strategies are tested on single- and multi- degrees-of-freedom linear structures subject both to analytical pulses and to a large set of NF records possessing pulse-like features. The resulting statistical evaluation, expressed by percentile response spectra, shows the advantages and disadvantages of a pulse-oriented TMD design, and improves the general understanding of TMDs effectiveness under impulsive ground motions.