ABSTRACT
Given the proliferation of dense seismic arrays around the world, it is possible to glean statistical information about the characteristics of major seismic events and their potential effects on structural designs. An analysis procedure developed by Masri et al. (1990), and later generalized in Smyth (1998) and Masri et al. (1998) for the representation and transmission of random excitation processes, provides a new tool to characterize strong
ground motions from large data sets. For details of this analytical compaction, representation, and transmission procedure, the reader is referred to Masri et al. (1998). In summary, the method involves two main stages of compaction of the random excitation data. The first stage is based on the spectral decomposition of the covariance matrix by the orthogonal Karhunen-Loeve expansion. The dominant eigenvectors are subsequently least-squares fitted with orthogonal polynomials to yield an analytical approximation. This compact analytical representation of the random process is then used to derive an exact closed-form solution for the nonstationary response of general linear multidegree-of-freedom dynamic systems.
