Anchor rods cast-in without enough projection

[GalileoG]

Hi all,

A few of the anchor rods for a single storey building (steel frame with x-bracing) were cast-in with barely enough projection where only a few threads are intercepted by the nuts. Other rods had just enough projection for the whole nut (top of rod flush with top of nut.)

Some of the bases can see some tension (100kN - which is not extremely high) at the cross-bracing joints. I was thinking perhaps just plug welding the nuts to the rods, does anyone see an issue with this? Should I have the contractor plug weld and in addition use new epoxy anchors?

I remember reading a while ago a rule of thumb that states rods/bolts should project 1.5" beyond the nut. I am wondering what structural reason there is for that and why wouldn't a nut that is flush be sufficient? (obviously a rod/bolt with just a few threads into the nut is not sufficient)

Thank you in advance,

Clansman

If a builder has built a house for a man and has not made his work sound, and the house which he has built has fallen down and so caused the death of the householder, that builder shall be put to death." Code of Hammurabi, c.2040 B.C.

 

[ToadJones]

Design Guide 1 has some fixes for this situation.

Coupling nuts are one option. This will require oversizing the holes in the baseplate and then using custom plate washers.

Welding the nut is not recommended

You can also weld extensions to the anchors if the material is weldable.

 

[dik]

Toad pretty much nailed it... also, if the nut is flush with the threaded part, that should be adequate... threads outside the nut are about as useful as 'runway behind you'...

Dik

 

[MiketheEngineer]

You might drill and epoxy new anchors. See Hilti for ideas

 

[WillisV]

Do not weld the nut. As long as the nut is flush with the threaded part its OK as previously stated.

Looks like the perfect situation for elocone nuts - I have used these several times - worked like a charm:

http://www.canam-steeljoist.ws/

http://www/v4/ePublica.nsf/va_looku...38482532AF85257116006D3AA3/$File/eElocone.pdf

 

[Once20036]

x2 on the Elecone - assuming that the base plate hasn't been grouted yet & depending on your anchor diameter (I don't think they're available below 3/4"). They're simple to install and easy to check that it's been done correctly.