A note on spectral velocity approximation at shorter intermediate periods

• Published in: Soil dynamics and earthquake engineering (1984) Vol. 141; p. 106422
• Main Authors: Pal, Ashish, Gupta, Vinay K.
• Format: Journal Article
• Language: English
• Published: Barking Elsevier Ltd 01.02.2021; Elsevier BV
• Subjects: Acceleration; Approximation; Constraining; Design PSA spectrum; Mathematical analysis; Pseudo spectral velocity; Response spectrum method; Seismic activity; Seismic response; Spectra; Spectral velocity; Velocity; Velocity-sensitive region; Response spectrum method; Velocity-sensitive region; Pseudo spectral velocity; Design PSA spectrum; Spectral velocity
• ISSN: 0267-7261; 1879-341X
• DOI: 10.1016/j.soildyn.2020.106422

It is common to use the design pseudo spectral acceleration (PSA) spectrum together with a modal combination rule to estimate the peak linear seismic response of a structural system. Some of the modal combination rules proposed so far require an accurate estimation of spectral velocity (SV) spectrum consistent with the given design PSA spectrum in order to account for modal correlations in a simple manner. The traditional pseudo spectral velocity (PSV) approximation of SV ordinates is reliable only for the velocity-sensitive region of the spectrum. More reliable approximations have therefore been developed in the recent years for the acceleration-sensitive and displacement-sensitive regions. In this work, the approximation developed for the acceleration-sensitive region is proposed to be applied on a greater range of periods, involving the shorter periods of the velocity-sensitive region, for a more accurate estimation of the SV spectrum. Regression equations are developed to predict the limiting period of the extended range by using the information available from the given PSA spectrum. A correction factor is also proposed to be applied to the SV estimates in order for those to have a smooth transition near the limiting period. •PSV approximation of SV ordinate reliable for velocity-sensitive region of spectrum.•Improvement proposed for the shorter periods of the velocity-sensitive region.•Approximation for the acceleration-sensitive region extended to longer periods.•Regression equations developed to predict limiting period of the extended range.•A correction factor also proposed for smooth transition near the limiting period.