Document: NUREG-0800
Document ID: 73dc4705-6dff-4f44-87ee-2a6f76cc6536
Document Type: srp
Title: OTHER SEISMIC CATEGORY I STRUCTURES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1319/ML13198A258.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.8.4
CFR Part: 
CFR Title: 

Content:
with ASCE 4-98, Section 3.5.3.2(2); (2) lateral earth pressure equal to the sum of the static earth pressure plus the dynamic earth pressure calculated using an 3.8.4-12 Revision 4 – September 2013 embedded SSI/ Finite Element Model (FEM) analysis model; and (3) lateral earth pressure equal to the fraction of the passive earth pressure that is effectively mobilized, which is dependent on the relative magnitude of the wall displacements against the soil that may occur for a given wall configuration. For case (3), the analysis should include, as a minimum, the fraction of the passive earth pressure assumed in the stability calculations performed in accordance with SRP Section 3.8.5. ASCE 4-98 Section 3.5.3.2(2) describes a method based on the well-known elastic solution by Wood (1973). This method assumes linear elastic strains in a homogeneous soil mass, a rigid wall with fixed base supported on stiff soil, and no displacement or sliding of the wall base relative to the underlying soil. Soil dynamics and wave propagation effects in the soil-wall system are also not considered. These assumptions may not be satisfied, for example, in the case of massive structures in deep soil sites where rocking could be important. Nevertheless, for cases where the assumptions of Wood’s solution are realistic, the method yields conservative estimates of the dynamic pressures. To account for a broad range of kinematic conditions, heterogeneity of the soil, as well as soil dynamics and wave propagation effects, a second method should be included based on soil-structure interaction (SSI) analysis of an embedded SSI/FEM model, as described in SRP Section 3.7.2. A limitation of such analysis is that it also assumes linear (or equivalent-linear) elastic strains in the soil. Therefore, a third method based on passive pressure should also be included to account for potential inelastic strains. The staff reviews the validity of the assumptions that are the basis of each of these three