Document: NUREG-0800
Document ID: 0240e5e6-f2f4-4cb7-a0c1-d68c92d70e15
Document Type: srp
Title: -
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1319/ML13198A223.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.7.2
CFR Part: 
CFR Title: 

Content:
on of ground motion incoherency in the free field has been investigated and characterized in terms of coherency functions, based on recorded earthquake data collected from dense array field tests. The ground motion incoherency effect on structural response is considered by incorporating coherency functions in analytical methods for SSI analyses. SSI analyses based on analytical methods that consider ground motion incoherency generally reduce structural response in high frequencies, compared to the response based on the traditional assumption of ground motion coherency. If the effect of incoherent ground motion is used to reduce the high frequency response, the potential effects of incoherent ground motion in increasing overturning and torsional responses need to be considered. The U.S. Nuclear Regulatory Commission (NRC) issued DC/COL-ISG-01 on May 19, 2008, describing methods acceptable to the staff for evaluating high frequency ground motion input. It includes guidance for conducting analyses that incorporate incoherent ground motion.