Influence of Structural Damping Uncertainty on Damping Reduction Factor

In practice, elastic response spectra are generally obtained by utilizing the 5% value for the damping ratio. The Damping Reduction Factor (DRF) allows to account for higher damping values. As proved by many literature studies, the DRF mainly depends on the structural damping ratio, until now essentially treated in a deterministic way. In this framework, the main aim of the present study is to explore a new definition of DRF including the effects of probabilistic uncertainties. Uncertainty is incorporated in both the random process, adopted to model the dynamic input, and the damping coefficient, introduced in the analysis as an uncertain variable.