Document: NUREG-0800
Document ID: 1f17483f-9659-41c2-9805-b715adfba8eb
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:
ntire SSI system are summarized as follows: A. Modeling of Structure. The acceptance criteria given under Subsection II.3 of this SRP section are applicable. B. Modeling of Supporting Soil. The effect of embedment of structure, ground-water effects, placement of compacted fills, and the layering effect of soil should be accounted for. For modeling of the support soil media, the lumped parameter (soil spring) method and the compliance function methods are acceptable provided that frequency variations and layering effects are incorporated. For the method of modeling soil media with finite boundaries, all boundaries should be properly simulated and the use of types of boundaries should be justified and reviewed on a case-by-case basis. Finite element and finite difference methods are acceptable methods for discretization of a continuum. The properties used in the SSI analysis should be those that are consistent with soil strains developed in free-field site response analyses. For structures founded on materials having a shear wave velocity of 8,000 feet per second or higher, under the entire surface of the foundation, a fixed base assumption is acceptable. In the SSI analysis of embedded structures using the substructure approach, the finite element discretization of the excavated soil volume should have a mesh