Document: NUREG-0800
Document ID: 6b7eddf4-f7ce-4821-9f11-e37070221e57
Document Type: srp
Title: DYNAMIC TESTING AND ANALYSIS OF SYSTEMS, STRUCTURES, AND
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML1613/ML16133A418.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.2
CFR Part: 
CFR Title: 

Content:
considered in determining the seismic response of systems, and components are reviewed. E. Combination of Modal Responses. When a response spectra method is used, the description of the procedure for combining modal responses (shears, moments, stresses, deflections, and accelerations) is reviewed, including that for modes with closely spaced frequencies. For example, when a response spectrum approach is used for calculating the seismic response of systems or components, the phase relationship between various modes is lost. Only the maximum responses for each mode can be determined. The maximum responses for modes do not generally occur at the same time, and these responses need to be combined according to an appropriate procedure selected to approximate or bound the response of the system. F. Analytical Procedures for Piping Systems. The analytical procedures applicable to seismic analysis of piping systems, including methods used to consider differential piping support movements at different support points located within a structure and between structures, are reviewed. G. Multiple-supported Equipment and Components with Distinct Inputs. The criteria and procedures for seismic analysis of equipment and components supported at different elevations within a building and between buildings with distinct inputs are reviewed. H. Use of Constant Vertical Static Factors. Where applicable, the justification provided for using constant static factors rather than a vertical seismic system dynamic analysis to compute vertical response loads for design of affected systems, components, equipment and their supports is reviewed. 3.9.2-4 Revision 4 – March 2017 I. Torsional Effects of Eccentric Masses. The criteria and procedures that are used to consider the torsional effects of eccentric masses (e.g., valve operators) in seismic system analyses are reviewed. J. Seismic Category I Buried Piping Systems. For Seismic Category I buried piping, the seismic criteria and methods