Stochastic Seismic Analysis of Large Linear Structural Systems Under Fully Non-stationary Spectrum Compatible Ground Motion

Abstract

Seismic assessment of linear systems is usually performed adopting the well-known modal analysis along with response spectrum technique. Limits of this approach are directly related to the hypothesis of stationary behavior of the response adopted for deriving most common modal combination rules, i.e. SRSS, CQC. Generally, the response of a structure under seismic actions is non-stationary and pertinent analyses have to be performed. In this chapter stationary and non-stationary stochastic models of the seismic action consistent with a given response spectrum will be initially discussed. Furthermore, a technique for determining the non-stationary response through the so-called non-geometric spectral moments will be addressed. Finally a modal correction technique will be proposed in order to make the proposed procedure competitive for coping with the analysis of large structural systems vibrating under random base excitations.