Document: NUREG-0800
Document ID: 972c263d-6bb5-40f8-86a0-890131a6b3bd
Document Type: srp
Title: -
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1235/ML12353A354.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.7.2
CFR Part: 
CFR Title: 

Content:
Draft Revision 4 - December 2012 - Performing an iterative linear analysis of the coupled soil-structure system. This accounts for the primary and secondary nonlinearities. In the event the nonlinear analysis is chosen, the results of the nonlinear analysis should be judged on the basis of the linear or equivalent linear analysis (NUREG/CP-0054). • Superposition of horizontal and vertical response as determined from separate analyses is acceptable (assuming nonlinear effects are not important) considering the simple material models now available. • The strain-dependent soil properties (e.g., shear modulus, damping) estimated from analysis of the seismic motion in the free field shall be consistent with the geotechnical information reviewed in SRP Section 2.5.4. • For a COL application referencing a standard plant design, where the site- specific GMRS fall below the standard plant CSDRS, the SSI evaluations are addressed in the standard plant design. However, it is necessary to confirm that the site-specific, strain-dependent soil properties, including consideration of uncertainty, are consistent with the generic site profiles used in the standard plant design. If this is not the case, then a site-specific SSI analysis is needed. • Enough SSI analyses should be performed so as to account for the effects of the potential variability in the properties of the soils and rock at the site. At least three soil/rock profiles should be considered in these analyses, namely, a best estimate (BE) profile, a lower bound (LB) and an upper bound (UB) profile in the evaluation of SSI effects. The properties of each layer of the site profile are typically defined in terms of its low-strain shear modulus and strain-dependent modulus degradation and strain-dependent hysteretic damping properties. These may be determined from dynamic laboratory testing of the site materials, information obtained from the published literature, or both. The set of properties appropriate for a