Welding Nut to Anchor Rod? 3

[Lascaris]

Hi,

I have a situation where a contractor has cut off part of an anchor rod so that there is not enough thread length to attach the nut on top of the baseplate. The rod in question is F1554 GR. 36 steel.

I'm aware that sometimes people will weld nuts to the bolt/rod, has anyone here done a repair like this before or does anyone know if there is any actual standard anywhere that sets out guidelines for this kind of thing?

 

[MikeHalloran]

The usual discussion is whether to accept situations where there are 0|1|2|3 full threads projecting from the installed nut.

If you can't even get the nut engaged, the contractor has a big problem.



Mike Halloran
Pembroke Pines, FL, USA

 

[Ingenuity]

Maybe try Elcone nuts: Link

 

[IFRs]

Try a coupling nut, used to fasten two threaded rods together.

 

[MotorCity]

It is not recommended because the anchor rod and nut are different grades of steel and are made using different treatment processes. The result is that the anchor rod and nut will each cool at different rates which leads to high localized stresses and increases the chance of thermal cracking. Have had success with Elcone nuts as suggested above.

 

[XR250]

The result is that the anchor rod and nut will each cool at different rates which leads to high localized stresses

I thought all carbon steel pretty much had the same heat capacity. I think anything you weld will cool at different rates simply due to the geometry.

 

[BSVBD]

What loads are being applied to the rod? Is there an uplift concern?

If the loads are not extreme, or if there are other rod anchors that can resist the applied loads, I've specified to weld the rod, all around, directly to the base plate.

Or drill another hole(s) through the baseplate and specify post-installed anchors.

 

[wannabeSE]

Here is a link to a recent Modern Steel article about field fixes for anchor rods:

https://www.aisc.org/globalassets/modern-steel/archives/2016/09/steelwise_1.pdf