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:
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 evaluation is performed using a nonlinear time history analysis that includes foundation sliding and uplift, the analysis should consider the following criteria: 1. The development of the set of time histories should follow the guidance described in SRP Section 3.7.1. This includes identification of the number of input time histories needed to perform the nonlinear time history analyses and the development of each of the individual time 3.8.5-10 Draft Revision 4 - December 2012 histories. In this case, the guidance in SRP 3.7.1 II.B, Option 2, for multiple sets of time histories is applicable. 2. To demonstrate an adequate factor of safety, the seismic input time histories should be increased by a factor equal to the factor of safety for the applicable load combination (e.g., increase the seismic input time history amplitudes by a factor of 1.1 for load combination C). No, or minimal sliding, and no overturning should be demonstrated for each of the time history analyses. 3. The mathematical model should include the effects of sliding and uplift between the foundation and the soil media using appropriate finite elements that can simulate sliding once the frictional limit is reached and can simulate contact surfaces that can transmit compression but not tension. 4. The sliding and overturning stability evaluation should consider the various significant parameters that were evaluated in the design basis seismic soil structure interaction analysis (e.g., range of soil profiles, concrete stiffness variation). 5. If the input motion applied at the foundation of the mathematical model is developed from the response of the linear soil structure interaction (SSI) analysis, justification is needed to demonstrate that any minimal sliding or uplift that might occur would not