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:
ation of the maximum and minimum Rankine states is more complex to delineate. Nevertheless, under seismic conditions, the total horizontal pressures are also bounded by the maximum and minimum Rankine states in a similar way as typical granular materials. It is important to note that the magnitude of soil deformations required to fully develop the maximum and minimum Rankine states could be relatively large. The kinematic configuration of the problem is thus fundamental. This is the reason why the seismic design of embedded or basement walls (so-called “non-yielding” walls or “restrained” walls, that are fixed at the base, at the top, and possibly at other intermediate bracing points) should be clearly differentiated from the seismic design of earth retaining walls (so-called “yielding” or “unrestrained” walls, that are free to displace or rotate at the base). In the case of unrestrained retaining walls, the standard seismic design approach is the Mononobe-Okabe method which is based on the assumed development of the minimum active state that is modified to include, in a pseudo-static manner, the additional horizontal and vertical seismic inertial loads exerted by the soil. The active state assumption is valid in this case because a stand-alone retaining wall is free to deform away from the soil but is unlikely to deform into the soil. In the case of restrained embedded walls, the typical configuration of the problem precludes the development of the minimum active state assumption. In NPP applications, the embedded walls are not stand-alone but are part of a much larger and more massive structure that, under seismic conditions, interacts dynamically with the surrounding soil in a complex oscillatory manner. The maximum passive state condition is a potential upper bound that would correspond to the walls being pushed into the soil by the overall motion of the structure. However, the magnitude of soil deformations/strains computed from typical seismic