Fractile levels for non-stationary extreme response of linear structures

A new method is developed for computing fractile levels of non-stationary extreme response of linear structures subjected to stationary, Gaussian white noise. The technique relies on suitable approximation of the integral which gives the number of level crossing by the response process and on simplifications of the second-order response statistics. Two approaches are investigated for obtaining closed form expressions for the fractile levels based on the Poisson approximation of the extreme value distribution. The better of these techniques is then extended to provide fractile levels based on the Vanmarcke approximation of the extreme value distribution. The results from the closed form expressions show very good agreement with corresponding numerical solutions of the non-linear equations for the Poisson and Vanmarcke fractile levels. Copyright (C) 1996 Elsevier Science Ltd.