I want to do incremental dynamic analysis (IDA) for my project, and for the hunt and fill algorithm, I need the 5% damped Spectral Acceleration at the structure’s first-mode period (Sa(T1; 5%)). Can I find it by using Seismosignal software directly? If not, how can I calculate Sa(T1; 5%) ?


1 Answer 1


ASCE 7-16 Section 11.4.5 provides the equations for the 5 percent damped spectral response acceleration, Sa, relative to period, T, in the following range.

0 ≤ T < T0, T0 ≤ T ≤ TS, TS < T ≤ TL, and TL < T

here is a link to a detailed solved example. look at Example 2, how to create design spectra with 5% damping. Except that the link, they have for the USDS application is dead use this link instead, find USDS data from addressto read Ss and S1 and other dates then use them to plug in this ASCE 7-16 example 2.

use example 2. open first


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