Multi-damping earthquake design spectra-compatible motion histories

Two iterative methods of developing time histories compatible with multi-damping spectra are presented. The common method of forcing agreement among design and calculated spectral values at several frequencies and multiple damping values may give poor. even meaningless results. The two simple iterative techniques presented here use acceleration impulse functions for "correcting" the time histories. In the first method the correction is calculated separately for each frequency and damping value and the maximum corresponding coefficient is used to correct the time history for the iteration. In the second method the solution is further improved by introducing a scale factor at each iteration. The effectiveness of the proposed techniques is illustrated by a comparison of a set of six multi-damping design spectra with spectral responses of a time history. (C) 2003 Elsevier B.V. All rights reserved.