SMACS: Probabilistic Seismic Analysis Code System

Lawrence Livermore National Lab., Livermore, California, through the OECD NEA Data Bank, Issy-les-Moulineaux, France.

Fortran IV (99.7%) and COMPASS (.3%); CDC7600 (P00396C760001).

The SMACS (Seismic Methodology Analysis Chain with Statistics) system of computer programs is one of the major computational tools of the U.S. NRC Seismic Safety Margins Research Program (SSMRP). SMACS is comprised of the core program SMAX, which performs the SSI response analyses, five preprocessing programs, and two postprocessors. The preprocessing programs include: GLAY and CLAN, which generate the nominal impedance matrices and wave scattering vectors for surface-founded structures; INSSIN, which projects the dynamic properties of structures to the foundation in the form of modal participation factors and mass matrices; SAPPAC, which projects the dynamic and pseudostatic properties of multiply-supported piping systems to the support locations, and LNGEN, which can be used to generate the multiplication factors to be applied to the nominal soil, structural, and subsystem properties for each of the response calculations in accounting for random variations of these properties. The postprocessors are: PRESTO, which performs statistical operations on the raw data from the response vectors that SMAX produces to calculate best fit lognormal distributions for each response location, and CHANGO, which manipulates the data produced by PRESTO to produce other results of interest to the user. Also included is the computer program SAP4 (a modified version of the University of California, Berkeley SAPIV program), a general linear structural analysis program used for eigenvalue extractions and pseudostatic mode calculations of the models of major structures and subsystems. SAP4 is used to prepare input to the INSSIN and SAPPAC preprocessing programs. The GLAY and CLAN programs were originally developed by J.E. Luco (UCSD) and H.L. Wong (USC).

SMACS performs repeated deterministic analyses, each analysis simulating an earthquake occurrence. Uncertainty is accounted for by performing many such analyses using different definitions of the seismic input and varying different system parameters according to a Latin hypercube experimental design. SMACS links seismic input with the calculation of soil-structure interaction (SSI), major structure response, and subsystem response. Seismic input is defined by ensembles of acceleration time histories in three orthogonal directions. SSI and detailed structure response are determined simultaneously using the substructure approach to SSI as implemented in the CLASSI family of computer programs. Subsystem response is determined from spectral accelerations at specified frequencies or by multi-support time history analysis of piping systems. Uncertainty in soil, structures, and subsystems is incorporated through selected parameter variations. In the SSI link, the selected parameters are the shear modulus and material damping in the soil; in the major structure and subsystem links, frequencies and modal damping properties are chosen.

None noted.

NESC executed the SMACS sample problem in approximately 45 CP seconds on a CDC CYBER170/875.

Approximately 252,000 (octal) words are required to run the SMACS sample problem. Memory requirements for the preprocessors and postprocessors are highly problem dependent.

LTSS (CDC7600); NOS 2.2 (CDC CYBER170).

**a) Included in the
document:**

O. R. Maslenikov, J. J. Johnson, L. Woon Tiong, M. J. Mraz,
S. Bumpus, and M. A. Gerhard, *SMACS - A System of Computer Programs for
Probabilistic Seismic Analysis of Structures and Subsystems, Volume I, User’s
Manual*, UCID-20413, Vol. 1 (March 1985).

O. R. Maslenikov, J. J. Johnson, L. Woon Tiong, M. J. Mraz, S.
Bumpus, and M. A. Gerhard, *SMACS - A System of Computer Programs for
Probabilistic Seismic Analysis of Structures and Subsystems, Volume II, Example
Problem*, UCID-20413, Vol. 2 (March 1985).

J. J. Johnson, G. L. Goudreau, S. E. Bumpus, and O.R.
Maslenikov, *Seismic Safety Margins Research Program Phase I Final Report -
SMACS - Seismic Methodology Analysis Chain with Statistics (Project VIII)*,
NUREG/CR-2015, Vol. 9 (UCRL-53021, Vol. 9) (July 1981).

Updated List Of External Routines Called By SMACS Programs, Lawrence Livermore National Laboratory Note (October 1986).

SMACS, NESC No. 1077, SMACS Tape Description, Implementation Information, and Revisions to Reference Documentation, National Energy Software Center Note 87-14 (December 5, 1986).

**b) Background information:**

S. J. Sackett, *Users Manual for SAP4; A Modified and
Extended Version of the U.C. Berkeley SAPIV Code*, UCID-18226 (May 1979).

G. L. Goudreau, *Preliminary User’s Manual for SAPPAC: A
Multisupport Modal Time Integrator and Transfer Function Plotter for SAP4
Models*, UCID-19054 (July 1982).

Included are the referenced documents, and Fortran source, libraries, sample problem input and output in a self-extracting DOS compressed file.

March 1999.

**KEYWORD:** SEISMIC