Document: NUREG-0800
Document ID: 47506195-5ce2-4c13-a914-02847d53c193
Document Type: srp
Title: of Reference 4.
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0523/ML052340570.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.5.2
CFR Part: 
CFR Title: 

Content:
13. Methods for Seismic Analysis of Category I Concrete Dams For the analysis of all Category I concrete dams, an appropriate approach that takes into consideration the dynamic nature of forces (due to both horizontal and vertical earthquake loadings), the behavior of the dam material under earthquake loadings, soil-structure interaction (SSI) effects, and nonlinear stress-strain relations for the soil, should be used. Analysis of earthen dams is reviewed under Section 2.5.6. 14. Methods for Seismic Analysis of Above-Ground Tanks Most above-ground fluid-containing vertical tanks do not warrant sophisticated, finite element, fluid-structure interaction analyses for seismic loading. However, the commonly used alternative of analyzing such tanks by the "Housner-method" (Ref. 5) may be inadequate in some cases. The major problem is that direct application of this method is consistent with the assumption that the combined fluid-tank system in the horizontal impulsive mode is sufficiently rigid to justify the assumption of a rigid tank. For flat-bottomed tanks mounted directly on their bases, or tanks with very stiff skirt supports, the assumption leads to the usage of a spectral acceleration equal to the zero-period base acceleration. Recent studies (Refs. 6, 7, 8, 9, and 10) have shown that for typical tank designs the frequency for this fundamental horizontal impulsive mode of the tank shell and contained fluid is such that the spectral acceleration may be significantly far greater than the zero-period acceleration. Thus, the assumption of a rigid tank could lead to inadequate design loadings. The SSI effects may also be very important for tank responses, and they may be considered for both horizontal and vertical motions. The acceptance criteria below are based upon the information contained in References 1 through 3 and Reference 5. These references also contain acceptable calculational techniques for the implementation of these criteria. The use of other approaches