Recovery of spectral absolute acceleration and spectral relative velocity from their pseudo-spectral counterparts

Design spectra for damping ratios higher than 5% have several important applications in the design of earthquake-resistant structures. These highly damped spectra are usually derived from a 5%-damped reference pseudo-acceleration spectrum by using a damping modification factor. In cases of high damping, the absolute acceleration and the relative velocity spectra instead of the pseudo-acceleration and the pseudo-velocity spectra should be used. This paper elaborates on the recovery of spectral absolute acceleration and spectral relative velocity from their pseudo- spectral counterparts. This is accomplished with the aid of correction factors obtained through extensive parametric studies, which come out to be functions of period and damping ratio.