SHORT ANCHOR BOLTS 4

[bernardoporta]

The case we are facing involves three columns whose anchor bolts were misplaced resulting in a situation where the top of the anchor bolt is below the top of the nut. Is plug welding into the nut an acceptable fix? or alternatively Is welding the nut to the base plate a good fix?
Thank you all for your opinions

 

[slickdeals]

Plug welding is not recommended. AISC recommends this

 

[structSU10]

See AISC Design Guide 1 2.11.3. They say welding the nut is not recommended. The design guide goes through more solutions. If you don't have access to this, let me know.

 

[hawkaz]

What is the purpose of these bolts? If they are resisting any moment, or have any tension, then no. If they are only in shear, I might allow it.

 

[IsaacStructural]

StructSU10 has the right idea, go to the design guide, it has information for just these sort of problems. That way you not only have a solution, but also a reference/justification for your approach.

M.S. Structural Engineering
Licensed Structural Engineer and Licensed Professional Engineer (Illinois)

 

[steellion]

Cut it off and use a post-installed anchor.

 

[nac521]

AISC Webinar last year recommend the following solutions for anchor rods too short:
1. Extend by welding a threaded rod
2. Use a coupling nut
3. Cut and use epoxy anchors
4. Weld base plate to rods
5. Perform analysis for threads engaged

 

[jgVA]

what would be a rational approach to performing an analysis for threads engaged? A proportional reduction based on length engaged to total nut height ratio?

 

[structSU10]

jgVA that is what they mean. It is also recommended that at least 50% of the threads should be engaged.

 

[spats]

Could you use a product such as the attached?

 

[bernardoporta]

THANK YOU ALL FOR THE POSTED ANSWERS.
THE END OF THE STORY IS THAT THE PIERS IN QUESTION WERE TOO HIGH.
I HAVE ORDERED THE PARTIAL DEMOLITION OF THE TOP OF THE PIERS, OF COURSE THE STEEL STRUCTURE HAD TO BE TAKEN DOWN.
FORTUNATELY WE WERE AT A STAGE WHEN IT WAS POSSIBLE TO DO THAT.

 

[msquared48]

Be careful of damage to the AB threads and the concrete the AB have already seen.

Mike McCann
MMC Engineering

http://mmcengineering.tripod.com

 

[dik]

Hydro demolition?

Dik