Document: NUREG-0800
Document ID: 8b79832c-b30e-4905-8cdc-033c0ff50dc4
Document Type: srp
Title: -
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1235/ML12353A354.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.7.2
CFR Part: 
CFR Title: 

Content:
ctra include the additional amplification. Also, the additional seismic loading on the overall structure and on the local region is needed for detailed structural design. In general, three-dimensional models should be used for seismic analyses. However, simpler models can be used if justification can be provided that the coupling effects of those degrees of freedom that are omitted from the three-dimensional models are not significant. iv. Modeling of the appropriate stiffness and damping for the various structural elements in the mathematical model is essential to obtain realistic seismic responses (e.g., in-structure response spectra (ISRS), building accelerations, member forces, and displacements). For reinforced concrete structures, the stiffness used in the model depends on the degree of concrete cracking which is a function of the level of