ESTS0012 CARES-ESTSC.

1. NAME OR DESIGNATION OF PROGRAM:  CARES.

3. DESCRIPTION OF PROGRAM OR FUNCTION

CARES, Computer Analysis for Rapid Evaluation of Structures, was developed for NRC staff use to determine the validity and accuracy of the analysis methods used by  various utilities for structural safety evaluations of nuclear power plants. CARES is organized in a modular format with the basic modules of the system performing static, seismic, and nonlinear analysis. In this release, only the seismic module is implemented. This module defines the design seismic criteria at a given site, evaluates the free-field motion, and computes the structural response and floor response spectra including soil-structure interaction. The eight options in CARES currently are: a general manager for the seismic module, deconvolution analysis, structural data preparation for soil-structure interaction (SSI) analysis, input motion preparation for SSI analysis, SSI analysis, earthquake  simulations/data, PSD (Power Spectral Density) related acceleration  time history/spectra analysis, and plot generation.

4. METHOD OF SOLUTION

The seismic module works in the frequency domain. Earthquake motion simulation is based on the fundamental property that any periodic function can be expanded in a series of sinusoidal waves. The computer uses a random number generator to produce strings of phase angles with uniform distribution in the 0-2pi range. Then, a linear correction procedure due to Scanlon and  Sacks is employed to derive an adjusted array of amplitudes. The acceleration ensemble is subsequently modified by a deterministic intensity function composed of three segments: an initial buildup, a stationary duration, and exponential steady decay. A parabolic correction procedure outlined by Jennings and Housner is applied to  the acceleration ensemble to bring the end velocity of the ground motion to zero.  The soil-structure system is represented by a three-dimensional lumped parameter type model. The structural model is built up from three-dimensional shear beam elements as well as three-dimensional spring type elements.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The superstructure model is restricted to about 20 degrees-of-freedom. The foundation configurations are primarily restricted to uniform half spaces. The free-field analysis is restricted to one-dimensional shear waves.

7. UNUSUAL FEATURES OF THE PROGRAM

CARES allows the user interactively to go through all basic steps of seismic analysis starting with a design ground motion to the floor response spectra used for subsystem analysis.

8. RELATED AND AUXILIARY PROGRAMS

The free-field response (convolution/deconvolution) methodology of CARES is based on the SLAVE code, while the soil-structure interaction analysis and development of floor response spectra is based on the SIM (Structure In Media) computer code. The algorithm for generating artificial ground acceleration time histories compatible with design response spectra is based on an earlier MIT computer program.

- J. Xu, A.J. Philippacopoulas, C.A. Miller, and C.J. Costantino:
  CARES (Computer Analysis for Rapid Evaluation of Structures)
  Version 1.0, Seismic Module, Theoretical Manual
  NUREG/CR-5588 (BNL-NUREG-52241), Vol. 1 (July 1990).
- J. Xu, A.J. Philippacopoulas, C.A. Miller, and C. J. Costantino:
  CARES (Computer Analysis for Rapid Evaluation of Structures)
  Version 1.0, Seismic Module, User's Manual
  NUREG/CR-5588 (BNL-NUREG-52241), Vol. 2 (July 1990).
- J. Xu, A.J. Philippacopoulas, C.A. Miller, and C.J. Costantino:
  CARES (Computer Analysis for Rapid Evaluation of Structures)
  Version 1.0, Seismic Module, Sample Problems
  NUREG/CR-5588 (BNL-NUREG-52241), Vol. 3 (July 1990).
- L. Reed:
  Errata (February 28, 1991).

11. HARDWARE REQUIREMENTS: MACHINE REQUIREMENTS

The program was installed at the NEA Data Bank on a
DELL 466/L PC/80486 with 66 MHz.

13. OPERATING SYSTEM UNDER WHICH PROGRAM IS EXECUTED:  UNIX.

The PC ran under MS-DOS 6.20.

15. NAME AND ESTABLISHMENT OF AUTHORS

C.J. Costantino, C.A. Miller, E. Heymsfield, and A. Yang
Constantino, Miller and Associates, Monsey, NY (U.S.A.)

File name	File description	Records
ESTS0012_01.001	Information file	128
ESTS0012_01.002	CARES execution batch file	43
ESTS0012_01.003	CARES option information	17
ESTS0012_01.004	CARES option 1 general manager module	0
ESTS0012_01.005	CARES option 2 convolution module	0
ESTS0012_01.006	CARES option 3 SSI analysis module I.	0
ESTS0012_01.007	CARES option 4 SSI analysis module II.	0
ESTS0012_01.008	CARES option 5 SSI analysis module	0
ESTS0012_01.009	CARES option 6 earthquake simulation module	0
ESTS0012_01.010	CARES option 7 PSD computations module	0
ESTS0012_01.011	CARES option 8 plotting module	0
ESTS0012_01.012	DOS file-names	11