The Earthquake Engineering Online Archive

PLUSH: a computer program for probabilistic finite element analysis of seismic soil-structure interaction

Romo, Miguel P.; Chen, Jen-Hwa; Lysmer, John; Seed, H. Bolton

UCB/EERC-77/01, Earthquake Engineering Research Center, University of California, Berkeley, 1977, 86 pages (555.6/R65/1980)

The computer program PLUSH is a further development of the complex finite element programs LUSH and FLUSH, which were designed to perform soil-structure interaction analyses. The new program retains the basic features of FLUSH, i.e., transmitting boundaries to simulate the infinite extent of the soil mass, beam elements, an approximate 3-D capability, deconvolution in the free field within the program, iteration on soil properties to simulate nonlinear effects, etc. The main difference between PLUSH and FLUSH is the way in which the input excitation is considered. Whereas in FLUSH the input excitation is specified as an acceleration time history, in PLUSH it is defined in terms of an input power spectrum or a median design response spectrum. In the latter case, the design response spectrum is converted into a corresponding power spectrum within the program. Thus PLUSH considers an infinite number of possible input motions simultaneously and the output, maximum accelerations, response spectra, etc., consist of statistical estimates of these variables with appropriate confidence limits.

Available online: http://nisee.berkeley.edu/documents/EERC/EERC-77-01.pdf (3 MB)