Document: NRC Regulatory Guide
Document ID: 3c238fa7-baa2-41c1-ac85-868fcda6b038
Document Type: regulatory_guide
Title: Design Limits, Loading Combinations, Materials, Construction, and Testing of Concrete Containments + HISTORY – HISTORY 07/2020 – DG-1372 , Proposed Revision 4 05/2019 – Periodic Review of Revision 3 – Revise 10/2015 – Periodic Review of Revision 3 – Reviewed with issues identified for future consideration 10/2006 – DG-1159, Proposed Revision 3 Prior to the issuance of DG-1159, RG 1.136 was entitled "Materials, Construction, and Testing of Concrete Containments (Rev. 4)
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML2010/ML20105A215.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.136
CFR Part: 
CFR Title: 

Content:
ted stress levels in yielding regions, especially under earthquake loading. This is also consistent with the requirements for mechanical splices in Sections 12.14.3.2 and 21.1.6 of ACI 349-13, “Code Requirements for Nuclear Safety-Related Concrete Structures and Commentary” (Ref. 46). As stated in the commentary for ACI 318-19 and ACI 349-13, the requirements for Type 2 mechanical splices are intended to avoid a splice failure when the reinforcement is subjected to expected stress levels in yielding regions in beyond-design-basis earthquake shaking. Type 1 mechanical splices (capable of developing 125 percent of the specified minimum yield strength of the bar, as specified in the ASME Code) on any DG-1372, Page 12 grade of reinforcement and Type 2 mechanical splices on Grade 80 and Grade 100 reinforcement may not be capable of resisting the stress levels expected in yielding regions, and therefore restrictions were placed on their use. ACI 349-13 structures are detailed for ductile response in the event of an earthquake larger than the SSE. Consistent with this philosophy, Type 1 splices are inadequate and are not permitted in nuclear safety-related concrete structures. Concrete containments in nuclear power plants are important safety-related structures; therefore, their criteria for mechanical or welded splices should not be less stringent than that of other seismic Category I structures, as defined in ACI 349-13. The containment structure could experience stresses in the yielding regions under design-basis accident and earthquake conditions. The specified or actual tensile strength of the steel reinforcing bars is used to calculate the ultimate capacity of concrete containment structures against the internal pressure as a measure of the safety margin above the design-basis accident pressure. Further, containment structures are expected to withstand beyond-design-basis accidents, earthquakes, and other extreme events. Consequently, Type 2 mechanical or welded