What is the projection length of Anchor rod from top bolt

[saruncivil]

Dear Engineers

What is the projection length of Anchor rod from top bolt, is there any standard reference for projection length from bolt..

please find the attachment for query. looking ahead for your reply.

thank you

By your Budding Engineer
Arun S

 

[UcfSE]

For the American question, the minimum is zero. That is to say the top of the bolt and the top of the nut may be flush. This is with respect to structural steel requirements. It would be advisable to provide a longer bolt, however, to account for tolerance and fit-up issues. 1-2 inches is often sufficient for typical structures. You can adjust from there.

 

[MintJulep]

While not directly applicable to an embedded anchor, you may find faq725-1331 of interest.

 

[ameyerrenke]

I agree with UcfSE. I dealt with this in the past, its been a while so I don't have the reference in front of me, but if all threads are engaged, the nut is fully engaged. I've allowed installers to eliminate washers to allow the nuts to fully engage as well. I assume you're dealing with a field issue. If in design phase, give them more than you think they need because something will always change in the field... IMO 1"-2" extra design projection should always be a minimum, possibly more depending the specific application.

 

[chicopee]

On my drawings I used to allow no more than three threads.

 

[ameyerrenke]

Chicopee, What do you do when the concrete installers embed the anchor more than .500" deeper than spec and the anchor nut is no longer able to fully engage because you only allowed for a maximum of .375" projection?

 

[fegenbush]

ameyerrenke,

That's when you go to the "AISC Field Fixes" website

http://www.aisc.org/content.aspx?id=2168

and look at the solutions presented for "Anchor Bolt Too Short."