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RE: L-shaped A490 Anchor Bolts

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Mechanical deformation:
My preference is to mechanically deform the threads to prevent nut 
rotation.  Mechanical deformation is performed by placing the tip of a 
punch at the point where the nut intersects the threaded shaft.  The punch 
is struck deforming the threads, locking the nut in place.

Even though you will not have a heat transfer from the arc initiation to 
the opposite side, you still can generate a crack from the arc initiation 
through the nut.  I have been challenged on this in the field by job 
superintendents and by engineers.  I have taken a hammer to tack welds on 
QT and alloyed steel and have fractured many welds to demonstrate brittle 
welds and crack initiation.  You might get by with 30 tacks before you 
crack a nut, but it is not worth the risk.  I have also been on a project 
in which 12 out of 12 nuts cracked.  Again, it is not worth the risk.  Tack 
 welds should only be used on weldable steels to provide temporary 
alignment prior to a finish weld.

Mechanical deformations are cheaper than welding (a process is eliminated 
in the fabrication) and there is no risk of a cracked element.  These are 
lessons learned from my days as an iron worker and polished up after I 
became an engineer a long, long time ago.

Regards, Harold Sprague

> Date: Fri, 3 May 2013 08:40:14 -0400
> From: jamesm(--nospam--at)
> Subject: Re: [SEAINT-SEAOSC] L-shaped A490 Anchor Bolts
> To: seaint-seaosc(--nospam--at)
> All,
> I usually call out the tack on the "unloaded" side of the nut. That is
> to say on the face closest to the "dead" end of the rod.
> - Mike
> Bill Polhemus <bill(--nospam--at)> wrote:
>> Except I'm not sure the stress level at this location ever approaches 
>> the point where a fracture is initiated.
>> William L. Polhemus, Jr. P.E.
>> 5

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