Document: NUREG-0800
Document ID: e7548e72-8c59-4c82-98dd-ff425e1de29a
Document Type: srp
Title: SEISMIC DESIGN PARAMETERS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1235/ML12352A305.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.7.1
CFR Part: 
CFR Title: 

Content:
he amplitude of these ground motions may be scaled but the phasing of Fourier components must be maintained. The adequacy of this set of ground motions, including- duration estimates, is reviewed on a case-by-case basis. Option 1: Single Set of Time Histories. To be considered acceptable, the response spectra generated from the artificial time history to be used as input ground motion in the free-field should satisfy the enveloping requirements for either Approach 1 or Approach 2 below: i. Approach 1. For Approach 1, the spectrum from the artificial ground motion time history must envelop the free-field design response spectra for all damping values used in the seismic response analysis. When spectral values (e.g., spectral accelerations) are calculated from the artificial time history, the frequency intervals at which spectral values are determined are to be sufficiently small. Table 3.7.1-1 (below) provides an acceptable set of frequencies at which the response spectra may be calculated. 3.7.1-11 Draft Revision 4 - December 2012 Table 3.7.1-1 Suggested Frequency Intervals for Calculation of Response Spectra Frequency Range (hertz) Increment (hertz) 0.2 - 3.0 0.10 3.0 - 3.6 0.15 3.6 - 5.0 0.20 5.0 - 8.0 0.25 8.0 - 15.0 0.50 15.0 - 18.0 1.0 18.0 - 22.0 2.0 22.0 - highest frequency of interest