Anchor Pryout Check Limitation (ACI 318 Appendix D)? 1

[waytsh]

I apologize if this has been asked before but I could not find anything in the archives. The PCA Notes on ACI 318 mention several times that anchor pryout is really only a concern on short stiff anchors. I was wondering if an actual limit where anchor pryout does not need to be considered is specified anywhere in the code? I know that the document "Design of Anchor Reinforcement in Concrete Pedestals" which is linked to in other posts mentions a limit of hef,min = 12 on Page 5. Although I would agree with this limit it appears to be a judgement call and not referenced by any code. Your thoughts? At what point, if any, are you guys ignoring the pryout on anchors?

Although I am asking this question in general the specific case I am working on has (6) - 1-1/2" diameter anchor rods with a 24" embedment and a 15" edge distance. After using supplemental reinforcing for tension and shear, pryout would be my controlling condition.

 

[WillisV]

I run up against this too. It is a rediculous check for longer anchors but there does not appear to be a code-related "out" for it. Tests have shown that (at least for standard headed studs) if they are about 5 times longer than they are in diamter pryout will not govern over the shear strength of the anchor (see Section I8.3 of the 2010 AISC Specification and this research:

https://www.ideals.illinois.edu/bitstream/handle/2142/11546/NSEL.Report.013.Part.I.pdf)

 

[waytsh]

WillisV,

Thank you for the reference and the document. Sorry I did not see it sooner, for some reason my email notification was not working.

Given the information referenced above are you comfortable ignoring pryout when hef/d < 5? Is it correct to say that if I am using shear and tension reinforcing that the only other checks in Appendix D that need to be met are pryout and steel strength? If I can ignore pryout I could make this pier a lot smaller. Right now I am at a 40" x 40" pier which seems very large.

Thanks,

Gary

 

[waytsh]

Almost forgot, side-face blowout would need to be checked as well assuming my anchors are close enough to the free edges.

 

[amec2004]

I seems there is no code clause on this and the only reference is what you mentioned "Design of Anchor Reinforcement in Concrete Pedestals"



anchor bolt design crane beam design

http://www.civilbay.com