SPECTR

Legacy software from 1972 that evaluates dynamic response spectra at various periods and presents the results as a log-log plot. Source code in FORTRAN and related reports can be downloaded from the earthquake engineering online archive maintained by University of California Berkeley.

SPECTR: Spectra Response Analysis

Donovan, Neville C.

Dames and Moore, San Francisco, California, Modified: T.F. Blake, Newbury Park, California [PC DOS version] 1990., 1972,

The program evaluates dynamic response spectra at various periods and presents the results as a log-log plot. On the basis of a given time-acceleration record, the program numerically integrates the normal convolution time integral for various natural periods and desired damping ratios. Relative displacements, relative and pseudo-relative velocities, absolute and pseudo-absolute accelerations are computed for natural periods from .01 seconds to 100 seconds. The program provides tables of displacement, velocity, and acceleration values with three measures of spectral intensity. A printer plot of desired damping ratios of the pseudo-relative velocity vs. natural period is presented on a 2 inch by 2 inch log-log grid.