Document: NUREG-0800
Document ID: 7c104096-d040-463a-a94b-a0af08ab3478
Document Type: srp
Title: DYNAMIC TESTING AND ANALYSIS OF SYSTEMS, STRUCTURES, AND
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0702/ML070230008.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.2
CFR Part: 
CFR Title: 

Content:
obtain maximum responses to each of the three components of the earthquake motion: in this case the method for combining the three-dimensional effects is identical to that described in Item (i) except that the maximum responses are calculated by the time history method instead of the spectrum method. (2) To obtain time history responses from each of the three components of the earthquake motion and combine them at each time step algebraically: the maximum response in this case can be obtained from the combined time solution. When this method is used, to be acceptable the earthquake motions specified in the three different directions should be statistically independent. E. Combination of Modal Responses. SRP Section 3.7.2 and RG 1.92,"Combining Modal Responses and Spatial Components in Seismic Response Analysis," present criteria and guidance for modal response combination methods acceptable to the staff. 3.9.2-13 Revision 3 - March 2007 F. Analytical Procedures for Piping Systems. The seismic analysis of Category I piping may use either a dynamic analysis or an equivalent static load method. The acceptance criteria for the dynamic analysis or equivalent static load methods are described in subsection II.2.A of this SRP section. G. Multiply-Supported Equipment and Components With Distinct Inputs. Equipment and components in some cases are supported at several points by either a single structure or two separate structures. The motions of the primary structure or structures at each of the support points may be quite different. A conservative and acceptable approach for equipment items supported at two or more locations is to use an upper-bound envelope of all the individual response spectra for these locations to calculate maximum inertial responses of multiply-supported items. In addition, the relative displacements at the support points should be considered. Conventional static analysis procedures are acceptable for this purpose. The maximum relative support