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RE: Short anchor bolt projection

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That is a good point.  If you do consider welding, a few nuts should be
spark tested to determine weldability (carbon equivalence).  Tack welds
should be avoided in general as they tend to become stress risers.  

Keep in mind, this whole thread presumed no tensile load.

Harold Sprague

> -----Original Message-----
> From:	Sherman, William [SMTP:ShermanWC(--nospam--at)]
> Sent:	Monday, October 09, 2000 3:10 PM
> To:	'seaint(--nospam--at)'
> Subject:	RE: Short anchor bolt projection
> Jimmy  C wrote:
> >  What would be amiss in field welding the nut to the anchor rod and
> welding the 
> > nut to the base plate?  
> According to responses given in Modern Steel Construction's "Steel
> Interchange" (accessible thru or, plug
> welding a less-than-fully-threaded nut to an anchor rod is not
> recommended.
> Charlie Carter points out that there is no test data published regarding
> this method, there is no prequalified welding procedure, and it is not
> clear
> what filler metal to use for A563 nut material. Thomas Powell states that
> a
> school in Louisiana had a spectacular failure when such plug welds failed
> during high winds. 
> I also question the general practice of welding nuts at anchor bolts.
> Unfortunately AISC does show nuts welded to anchor bolts in its "Column
> Base
> Plates" Steel Design Guide, where anchor plates are shown tack welded to
> nuts at the bottom bearing for anchor bolts. I have been told by a welding
> specialist that due to the carbon content of standard nuts, tack welding
> is
> not recommended as it could cause the nut to crack. Full fillet welding
> around a nut may be feasible, but proper welding procedures should be used
> based on the carbon content. I'd prefer not to rely on the field welder to
> follow such procedures, unless clearly defined.