Anchor Rod Nuts

[WJA]

Hi folks

I am being told by a supplier that they need long nuts above the baseplate (a 3.5" long nut for a 1.25" diameter grade 105 threaded rod) in order to develop the tensile capacity of the anchor rod. Is there merit to this statement? My understanding was that the standard size nuts would have a sufficient number of threads. How would I determine the minimum length of the nut?

 

[oldestguy]

No answer from me, butI'd go to a mechanical eng. site for this question.

 

[Guest090822]

Usually the nut is as tall as the diameter of the anchors rod. My only guess for needing a tall nut would be that the materials are different grades, otherwise the supplier doesn’t know what they are talking about.

 

[BridgeSmith]

It may be as TheRick109 suggests, and they're trying to use a lower strength nut on the high strength anchor rod. Otherwise, the the proper grade and type of nut should suffice. Either that, or they happened to have a bunch of 1 1/4" couplers lying around that they're trying to pass off as nuts, so they won't have to order the correct hardware.

 

[Ron247]

My understanding has always been the correct standard nut for a given rod is long enough to develop the strength of the rod. Find the correct nut for the rod and see how tall it is or how many threads it has.

 

[JStephen]

Assuming these are F1554 bolts, the F1554 standard tells you what nuts to use. The Grade 105 require a higher grade nut, but it's still a hex or heavy hex nut.

 

[Settingsun]

A builder once got the projection for anchor bolts wrong and the nuts couldn't be put fully on. Not much literature on the subject but what existed agreed that almost all the load is transferred through the first three threads.

 

[Rabbit12]

Chat with the guys from Portland Bolt. They are experts in the field of anchor rods and the like. They have a very convenient online chat option.

 

[dauwerda]

To add to what Rabbit 12 suggested, Portland Bolt has all sorts of good information on their website, including this handy nut compatibility chart:

https://www.portlandbolt.com/technical/nut-compatibility-chart/

 

[azcats]

This page gets more into the allowable substitutions for F1554-105. I see a lot of A194-2H nuts used.

[URL unfurl="true"]https://www.portlandbolt.com/technical/specifications/astm-f1554/[/url]