Document: NUREG-0800
Document ID: 6d95bc89-e14a-4d87-bf91-1d1760c2aff8
Document Type: srp
Title: FOUNDATIONS
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1235/ML12353A388.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.8.5
CFR Part: 
CFR Title: 

Content:
ding. If sliding resistance is the sum of shear friction along the base mat and contribution of soil lateral pressure up to the full passive pressure capacity induced by embedment effects, adequacy of the analysis to consider these effects is addressed using a consistent lateral displacement criterion. This involves the use of static versus dynamic coefficient of friction consistent with the use of partial versus full passive pressure. Whether the selection of the coefficient of friction used in the sliding stability analysis considers the various sliding interfaces (e.g., soil shear failure, concrete to soil, waterproofing to soil, concrete basemat to concrete mudmat). If the stability evaluation is performed based on a pseudo-static approach, using the maximum seismic demand loads (e.g., maximum forces in the two horizontal directions and one vertical direction), then the factors of safety for sliding and overturning can be determined by the ratio of capacity to demand loads. However, if a linear time history analysis approach is utilized, then the factor of safety can be calculated at each time step throughout the time history. The minimum value of the factors of safety calculated in this manner should be compared against the acceptance criteria for that load combination. For the pseudo-static and time history analysis methods, all three directional demand forces should be considered to act simultaneously. Therefore, the resultant seismic forces (horizontal resultant force for sliding from the two horizontal forces and similarly the resultant overturning moment for overturning stability) should be considered. In the case of the sliding evaluation, if instead of using the resultant horizontal force with the vertical force, the pairs of each horizontal force with the vertical force are evaluated separately, then the frictional resistance in the horizontal directions should be apportioned considering the existence of the two horizontal forces. If the stability