Document: NUREG-0800
Document ID: 3e1b34e6-0e9d-4d8f-9338-98860adfc499
Document Type: srp
Title: CONCRETE CONTAINMENT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0705/ML070570009.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.8.1
CFR Part: 
CFR Title: 

Content:
ity test performed in accordance with Article CC-6000 of the ASME Code. Also, based on load combinations that include the design pressure load with earthquake loads, additional concrete cracking would be expected to occur. Concrete cracking can cause redistribution of member forces because of the various loadings applied to the structure. Concrete cracking can also affect the stiffness of the containment and cause shifting of the natural frequency, thereby affecting the response/loads used to design the containment. Accordingly, the analysis used to calculate the dynamic response of the containment resulting from dynamic loads such as earthquake and hydrodynamic loads (if applicable) needs to consider the potential effects of concrete cracking, if significant. The approach used should include the effect of redistribution of the various loads caused by concrete cracking. With improvements in the development of computer programs for analysis of concrete structures, the evaluation of concrete cracking can be analyzed directly within the finite element model. Alternatively, additional analyses can treat the effect of concrete cracking by determining the response of the containment to variation in the stiffness characteristics of the containment shell (e.g., shear stiffness and tensile membrane stiffness reduction). As stated in CC-3320 of the ASME Code, 3.8.1-14 Revision 2 - March 2007 the effects of reduction in shear stiffness and tensile membrane stiffness resulting from cracking of the concrete should be considered in methods for predicting the maximum strains and deformations of the containment. Thus, concrete cracking needs to be considered depending on the stress levels caused by the most severe seismic load combination. Provide technical justification, if cracking is not considered or is determined to be insignificant. Sections 3.1.3 and C 3.1.3 of ASCE 4-98 provide additional guidance for modeling the stiffness of concrete elements. The staff reviews the