The Earthquake Engineering Online Archive

An optimal discretization of random fields

Li, Chun-ching; Der Kiureghian, Armen

UCB/SEMM-1992/04, Dept. of Civil Engineering, University of California, Berkeley, 1992-03, 33 pages (500/C23/92/04)

A new method for efficient discretization of random fields is introduced (i.e., representation in terms of random variables, a characteristic important in finite element reliability analysis by first order, FORM, and second order, SORM, reliability methods). The efficiency of the discretization is measured by the number of random variables required to represent the field with a specified level of accuracy. The method is based on principles of optimal linear estimation theory. It represents the field as a linear function of nodal random variables and a set of shape functions, which are determined by minimizing an error variance. Further efficiency is achieved by spectral decomposition of the nodal covariance matrix. The method is particularly useful for stochastic finite element studies involving random media, where there is a need to reduce the number of random variables to reduce the amount of required computations.

Available online: http://nisee.berkeley.edu/documents/SEMM/SEMM-92-04.pdf (1 MB)