Document: NUREG-0800
Document ID: 73747cf4-ff95-449b-b6b0-53dc0755b9e0
Document Type: srp
Title: OTHER SEISMIC CATEGORY I STRUCTURES
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1235/ML12353A382.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.8.4
CFR Part: 
CFR Title: 

Content:
sures. This stress state is termed the active state. The minimum value of this active state is estimated for ordinary conditions as Ka x σv, where Ka is called the Rankine active coefficient of earth pressure. The value of Ka is less than Ko and is approximately 0.33. If the wall or structure moves into the surrounding soil, the pressures increase above the static at-rest condition. This increased stress state is termed the passive state. The maximum value of this passive state is estimated for ordinary conditions as Kp x σv, where Kp is called the Rankine passive coefficient of earth pressure. For ordinary granular soils, the value of Kp is approximately 3.0 or more. For typical granular materials, it is expected that the total pressures acting on the wall under seismic conditions will change from the static at-rest case to no less than the Rankine active pressure and to no more than the Rankine passive pressure. Therefore, for ordinary granular materials, the total horizontal pressure coefficients (static plus dynamic) can be expected to vary during the seismic motions from about 0.5 to no less 3.8.4-39 Draft Revision 4 – December 2012 than 0.33 and to no more than 3.0. For more general soil materials that possess both cohesive and frictional shear strength, the formulation 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)