Document: NUREG-0800
Document ID: 1f106a50-722f-45fa-952a-2e7ab7d836c1
Document Type: srp
Title: DYNAMIC TESTING AND ANALYSIS OF SYSTEMS, COMPONENTS, AND EQUIPMENT
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052360453.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.9.2
CFR Part: 
CFR Title: 

Content:
stant Vertical Static Factors The use of constant vertical load factors as vertical response loads for the seismic design of all Category I systems, com- ponents, equipment, and their supports in lieu of the use of a vertical seismic system dynamic analysis is acceptable only if it can be justified that the structure is rigid in the vertical direction. The criterion for rigidity is that the lowest fre- quency in the vertical direction is more than 33 hz. i. Torsional Effects of Eccentric Masses For seismic Category I systems, if the torsional effect of an eccentric mass such as a valve operator in a piping system is judged to be significant, the eccentric mass and its eccen- tricity should be included in the mathematical mode. The criteria for significance will have to be determined on a case- by-case basis. j. Category I Buried Piping Systems For Category I buried piping systems, the following items should be considered in the analysis: 3.9.2-10 Rev. 2 - July 1981 (1) The inertial effects due to an earthquake upon buried pip- ing systems should be adequately accounted for in the analysis. Use of the procedures described in References 11 and 14 is acceptable. (2) The effects of static resistance of the surrounding soil on piping deformations or displacements, differential movements of piping anchors, bent geometry and curvature changes, etc., should be adequately considered. Use of the procedures described in Reference 15 is acceptable. (3) When applicable, the effects due to local soil settle- ments, soil arching, etc., should also be considered in the analysis. k. Interaction of Other Piping with Category I Piping To be acceptable, each non-Category I piping system should be designed to be isolated from any Category I piping system by either a constraint or barrier, or should be remotely located with regard to the seismic Category I piping system. If it is not feasible or practical to isolate the Category I piping sys- tem, adjacent non-Category I piping should be