Document: NUREG-0800
Document ID: 1f9c2564-a291-4ef6-b7a8-4105b4643ddf
Document Type: srp
Title: -
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1319/ML13198A223.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.7.2
CFR Part: 
CFR Title: 

Content:
Revision 4 – September 2013 laboratory testing of the site materials, information obtained from the published literature, or both. The set of properties appropriate for a given soil is reviewed for its adequacy. Guidance is also provided in DC/COL-ISG-017. For a particular site, the iterated shear modulus and damping values are typically determined from the results of a number of free-field site response analyses, which are intended to account for the effects of the site-specific design ground motions as well as the site nonlinear properties. If only a single site response calculation is performed, with the low strain property of each material layer selected at its BE value, the resulting iterated property is then determined. The upper and LB values of soil/rock shear modulus (G) can then be defined in terms of their BE values as: GLB = GBE / (1+COV) GUB = GBE x (1+COV) where COV is the coefficient of variation considered appropriate for the site materials. The corresponding damping properties should be defined at the compatible strains associated with the shear moduli. If many site response calculations are performed (60 or more site response calculations) using Monte Carlo techniques to develop site properties, these calculations are typically used to determine the BE, LB and UB iterated site properties. The BE properties are determined from the mean of the resulting properties and the UB and LB values selected from the +/- one sigma values. Guidance for the site response analysis is provided in SRP Section 2.5.2. For well-investigated sites (see RGs 1.132 and 1.138), the COV should be no less than 0.5. For sites that are not well investigated, the COV for shear modulus shall be at least 1.0. These COV requirements apply to the “single site response calculation,” as well as the “many site response calculations” described above. In no case should the LB shear modulus be less than that value consistent with standard foundation analysis that yields