Document: NUREG-0800
Document ID: 072325a8-02ea-4d59-bb3f-06592c340804
Document Type: srp
Title: The Aluminum Association, Specification for Aluminum Structures
Source: NUREG-0800
Source URL: https://www.nrc.gov/docs/ML0520/ML052070327.pdf
Revision Date: 2023-06
Chapter: 3
Section ID: 3.4
CFR Part: 
CFR Title: 

Content:
g the validity of the 45-degree failure-cone theory to licensees, architect-engineers, bolt manufacturers, and the code committee members when it met with them. The data showed that the actual failure cone was about 35 degrees and the use of the 45-degree cone theory could be unconservative for anchorages of deep embedment, and for the anchorage of groups of bolts. The code committee, having done some research of its own, recently agreed with the staff's finding. The code committee is now revising this section. In the meantime, the staff position on issues related to this section is to ensure adoption of design approaches consistent with the test data through case-by-case review. Section B.5.1.1 - Tension In this section, ACI states a criterion for ductile anchors. The criterion is that the design pullout strength (force) of the concrete as determined in Section B.4.2 exceeds the minimum specified tensile strength (force) of the steel anchor. Any anchor that meets this criterion is qualified as a ductile anchor and, thus, a low safety factor can be used. The staff believes that the criterion is deficient in two areas: (1) the design pullout strength of the concrete, so calculated, is usually DRAFT Rev. 2 - April 1996 3.8.4-42 higher than the actual strength, as has been stated in Section B.4.2 above and (2) anchor steel characteristics are not taken into consideration. For example, Drillco Maxi-Bolt Devices, Ltd. claims that its anchors are ductile anchors and, thus, can use a low safety factor. The strength of the Maxi-Bolt is based on the yield strength of the anchor steel, which is 724 MPa (105 ksi). The embedment length of the anchor, which is used to determine the pullout strength of the concrete, is based on the minimum specified tensile strength of the anchor steel of 862 MPa (125 ksi). The staff believes that the 19 percent margin (125/105) for the embedment length calculation is insufficient considering the variability of parameters affecting the concrete