Anchor Bolts Too Short - Repair??? 1

[NKK]

I would appreciate your comments on the following issue:
The anchor bolts (1" dia.) for few steel column base plates are installed improperly and are projecting no more than 1/2" above the base plate. The problem was detected during a field visit at which time the structural steel was already erected so all repairs shall be planned with respect to this fact. Thanks.

 

[CoryPad]

I assume you are asking for advice on how to fix this condition so that the structure can be used without having to destroy it and redo it. If so, here is one way to fix it: use a nut that can project into the hole of the base plate. You may need to enlarge the plate holes, and you may need to specially fabricate the nut, but it should work fine. The basic nut geometry should be like a stepped shaft - the large diameter will rest on top surface of the base plate while the small diameter (that has a tapped hole in it) projects into the base plate and will engage the existing anchors. If you need a better explanation or schematic image, please contact me.

Cory
cpadfield@omnimetalslab.com

 

[evelrod]

NKK---With the column erected and not able to be removed leaves you with only a few options. Normally the bolts could be exteded by mechanical means or welding but in this case that won't be possible. You must consult with your local inspector on this but it is possible to weld the anchor bolts to the base plates with proper preparation and welding technique. Properly inspected and ND tested , of course. It is a fairly common practice in most areas and correctly done is a safe and reliable alternative to removing the base plates. Welding extension to the bolts could possibly be done but with great difficulty (you still would need NDT and sufficient spacers under the nut) and cost.

My opinion, based on 38 years of experience at this sort of thing,---Who was in charge of this structure that this condition wasn't detected on the FIRST column? What was the inspector doing? Why no RFI's at the begining of erection? I AM a nice guy but heads would roll on this one! Oh yes, I am not going to leave the engineer out on this one, either! He/she should have checked or had better control of the inspection process!

Sorry for the rant, I really dislike incompetance, and this sort of thing happened to me more than a few times.

Use qualified UNION IRONWORKERS on your next project.


Rod

 

[Qshake]

This question has come up before. I suggest that you use the search function to find it as there were several good comments on the subject.