Stochastic response of structures with uncertain-but-bounded parameters

The uncertainty plays an important role in structuralengineering. It is largely recognized that the uncertainty mayaffect both external excitations and structural parameters.However, while the numerous available data permit to modelwith good accuracy the excitations as stochastic processes,unfortunately the data about the structural parameters are quitelimited. It follows that the probabilistic approach cannot berealistically applied to represent structural uncertainties;indeed, it requires a wealth of data, often unavailable, to definethe probability distribution density of the fluctuating structuralparameters. Non probabilistic approaches can be alternativelyused to treat these uncertainties. In this framework, the intervalmodel seems today the most suitable analytical tool.The aim of this paper is to evaluate the range of therandom response of linear structural systems, with slightvariation of the uncertain-but-bounded parameters, subjected tostochastic Gaussian excitations by applying the so-calledinterval perturbation method