Seismic Safety Margins Research Program. Phase I Final Report - SMACS - Seismic Methodology Analysis Chain with Statistics (Project VIII)

摘要

SMACS, one of the major computational tools of the SSMRP, links the seismic input with the calculation of soil-structure interaction (SSI) and detailed structural response are determined simultaneously, using the substructure approach to SSI as implemented in the CLASSI family of computer programs. To determine the response of piping systems, the authors selected the pseudostatic-mode method as the most efficient method for accounting for independent multisupport excitations. Uncertainty was explicitly propagated through each step of the SMACS calculational scheme. Variability in the seismic input was incorporated in the calculations by using ensembles of time histories. In the remaining links of the calculations, selected parameters were systematically varied to represent all sources of uncertainty. In order to compute uncertainties in the computed building and subsystem responses, SMACS performs repeated deterministic analyses, each analysis simulating an earthquake occurrence. By performing many such analyses and by varying the values of several input parameters, the authors are able to calculate statistical distributions for the calculated structural responses (forces and accelerations) reflecting the uncertainty in the input parameters. Parameter values for each simulation were selected from assumed probability distributions according to a Latin hypercube experimental design.