Document: NRC Regulatory Guide
Document ID: 0ae1e098-eccd-43e7-b12e-43b05aa1fe48
Document Type: regulatory_guide
Title: Safety-Related Concrete Structures for Nuclear Power Plants (Rev. 3)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML1617/ML16172A240.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.142
CFR Part: 
CFR Title: 

Content:
ss) by 10 percent for the conditions in Section 9.2.10 of ACI 349-13. 3.7 The NRC staff does not endorse use of strength reduction factor φ = 0.75 in section 9.3.2.3 and R9.3.1of ACI 349-13 for shear critical members such as low-rise shear walls, portions of walls between openings or diaphragms. To address the lower ductility of shear critical members versus flexure-critical members, use φ = 0.60 for shear critical members. 3.8 ACI 349-13, Section 21.9.9, discusses provisions for columns supporting discontinued shear walls. The staff does not endorse the generic use of this type of structural configuration in nuclear safety-related structures. 4. Regulatory Position 4 The NRC makes the following exceptions, enhancements, and supplements to ACI 349-13, Appendices A, C, D, and F: 4.1 Appendix A, “Strut-and-Tie Models” The application of strut-and-tie models in design needs justification by licensees or applicants each time that it is used. 4.2 Appendix C, “Alternative Load and Strength-Reduction Factors” The load combinations of Appendix C are acceptable alternatives to those of ACI 349-13, Chapter 9, with the exceptions noted below. Table 3 shows all load definitions (e.g., D, L, To) as given in ACI 349-13 and ASCE 7-05, “Minimum Design Loads for Buildings and Other Structures,” issued 2005 (Ref. 24). DG-1283, Page 13 Table 3 Load Definitions Required Strength (U) Load Combination ACI Equations U = 1.4D + 1.4F + 1.7L + 1.7H + 1.7Eo + 1.7Ro+ 1.4Ccr (C9-2) NL + SEL U = D + F + L + H + Ta + Ra + 1.4Pa + Ccr (C9-6) NL + AL U = 1.05D + 1.05F + 1.3L + 1.3H + 1.2To + 1.3Ro (C9-9) 75% NL + TL U = 1.05D + 1.05F + 1.3L + 1.3H + 1.3Eo + 1.2To + 1.3Ro (C9-10) 75% (NL + SEL) + TL U = 1.05D + 1.05F + 1.3L + 1.3H + 1.3W + 1.2To + 1.3Ro (C9-11) 75% (NL + SEL) + TL 4.2.1 Hydrodynamic loads associated with seismic loads (i.e., the impulsive and sloshing loads for fluids in tanks) are to be considered as Ess in load combinations (C9-4) and (C9-8). Hydrodynamic loads