Document: NUREG-0800
Document ID: b9ed2498-b251-4bea-a539-c879ec8c002f
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 SRP Section 3.7.2 Description of Changes Section 3.7.2 “SEISMIC SYSTEM ANALYSIS” This SRP section affirms the technical accuracy and adequacy of the guidance previously provided in Revision 3, dated March 2007 of this SRP. See ADAMS Accession No. ML070640311. I. AREAS OF REVIEW 1. Revised the designation of the primary review responsibility to be the organization responsible for structural reviews. 2. Enhanced Item 4 “Soil-Structure Interaction” to indicate review of generic site profiles for DC application. See item 5 below (under “Acceptance Criteria”) for the technical rationale for this change. 3. Added text to reference additional ISG provided in ISG-01, ISG 017, and ISG-20. II. ACCEPTANCE CRITERIA 1. Enhanced SRP Section 3.7.2 II.3.C by adding item (iv) regarding modeling of structures for the effects of concrete cracking. The technical rationale for this change is as follows. When developing mathematical models to perform seismic analysis of concrete structures, the stiffness of the structural elements is affected by the degree of concrete cracking. To ensure that the mathematical models realistically represent the concrete structures, the SRP guidance was enhanced to provide additional criteria on how to consider the effects of concrete cracking on the structural stiffness of members used in the models. Concrete cracking can reduce the stiffness and increase damping of structures, which would reduce the frequencies of the structure and thereby may affect the seismic response analysis. In past licensing applications, questions have arisen regarding the proper consideration of the effects of concrete cracking when performing seismic analysis of structures. Part of this reflected a need for additional guidance in the SRP on acceptable methods for treating the effects of concrete cracking. It is well recognized that the use of the appropriate stiffness for the various structural elements in the mathematical model is