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Re: L-shaped A490 Anchor Bolts

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I agree that deformed threads are the way to go, but in my experience
given the option contractors don't choose to peen. Typical note is
"tack, peen, or double nut: contractors option". I don't lose too much
sleep over a tack weld on a Grade 36 anchor rod with an A563 Gr. A nut
in a non-critical application. It is probably against the fine print of
the code either way, but obviously some engineering judgement is in

- Mike

On Fri, May 3, 2013, at 09:14 AM, Harold Sprague wrote:
> 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.
> Welding:
> 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.

Truncated 919 characters in the previous message to save energy.

  Michael James

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