Document: NRC Regulatory Guide
Document ID: 1d715751-9321-4481-a46f-4ff802a5efe0
Document Type: regulatory_guide
Title: Service Limits and Loading Combinations for Class 1 Linear-Type Supports + HISTORY – HISTORY 10/2006 – DG-1168 , Proposed Revision 2
Source: NRC Regulatory Guide Division 1
Source URL: https://www.nrc.gov/docs/ML0630/ML063000449.pdf
Revision Date: 2023-06
Chapter: 
Section ID: RG-1.124
CFR Part: 
CFR Title: 

Content:
ction III derives critical buckling stresses with normal design margins. Because buckling prevents “shakedown” in the load-bearing member, NF-3322.1(c) should be controlling. Also, buckling is the result of the interaction of the geometry of the load-bearing member and its material properties (i.e., elastic modulus E and minimum yield strength Sy). Because both of these material properties change with temperature, calculation of the critical buckling stresses should use the values of E and Sy of the component support material at temperature. Tensile and shear stress limits and their nonlinear interaction are used to derive allowable service limits for bolted connections, which also change with the size of the bolt. For this reason, the increases permitted by NF-3321.1(a) and F-1334 of Section III do not directly apply to allowable tensile stresses and allowable shear stresses for bolts and bolted connections. As specified in F-1335 of Section III, the allowable increase in tensile stress for bolts should not exceed the lesser value of 0.70 Su or Sy, at temperature, and the allowable increase in shear stress for bolts should not exceed the lesser value of 0.42 Su or 0.6 Sy, at temperature. For the linear-elastic-analysis method, F-1334 permits an increase of tension limits for the Level D service limits by a variable factor that is the lesser of 2 or 1.167Su/Sy if Su >1.2Sy, or 1.4 if Su #1.2Sy. Depending on whether the section considered is a net section at pinholes in eyebars, pin-connected plates, or built-up structural members, Ft may assume the lesser value of 0.45Sy or 0.375Su (as recommended by this guide for a net section of pinholes, for example) or the lesser value of 0.6Sy or 0.5Su (for a net section without pinholes, for example). DG-1168, Page 4 Design by Load Rating NF-3380 of Section III specifies the qualification of linear-type supports to Service Level A, B, and C limits, using load-rating criteria. F-1334.8 specifies the qualification of