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Re: A490 bolts

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Good Point

I was assuming a "normal" office building with temperature and humidity control without obnoxious chemicals.  Certainly a building with a corrosive atmosphere would require special treatment but it would go far beyond just the bolts.  All the structural steel, bolts, metal studs, roofing, anchor bolts, equipment, doors, etc., etc. would need to be addressed.

Thomas Hunt, S.E.
ABS Consulting



desi j kiss <djkiss55(--nospam--at)juno.com>

10/16/2002 09:06 AM
Please respond to seaint

       
        To:        seaint(--nospam--at)seaint.org
        cc:        
        Subject:        Re: A490 bolts



........"If your structure is inside a building then the bolts probably
do not need
to be coated at all......"

This could become a very MISLEADING issue.   I've seen and heard this
before.
Some engineers assume that if inside a structure corrosion doe's not
occur and
therefore are becoming very ignorant.   Statements such as above may
become
misleading, especially, if the inside of a structure that produces a
corrosive environment
such as: manufacturing and chemical plants, theme park flumes, etc.

Desi J. Kiss, PE





On Wed, 16 Oct 2002 07:19:14 -0700 THunt(--nospam--at)absconsulting.com writes:
> Javier,
>
> The reason A490 bolts can not be galvanized is due to the
> possibility of
> hydrogen embrittlement.  This is a concern when tensile strengths
> approaches 200 ksi.  A490 bolts are specified at 170 ksi but due to
> manufacturing variances it was close enough to incorporate the
> restriction.
>
> If your structure is inside a building then the bolts probably do
> not need
> to be coated at all.  If your structure is outside and the steel is
> galvanized then I would switch to A325 bolts which can be
> galvanized.  If
> your structure is outside and the steel is being painted then the
> A490
> bolts can be spot painted after installation.
>
> As a general comment, I would say you should be careful when
> specifying
> A490 bolts to make sure that the sizes you are specifying are
> readily
> available especial in remote areas and countries.  There is also a
> concern
> that if you are using both A325 and A490 bolts and your construction
> team
> is suspect then there is a possibility that they could be
> mis-installed.
>
> Thomas Hunt, S.E.
> ABS Consulting
>
>
>
>
>
>
> "Javier Encinas" <jencinas(--nospam--at)coqui.net>
> 10/15/2002 06:19 PM
> Please respond to seaint
>
>  
>         To:     <seaint(--nospam--at)seaint.org>
>         cc:
>         Subject:        A490 bolts
>
>
> Does anybody know why galvanizing A490 bolts is not allowed? Also,
> what
> measures are usually taken to protect these bolts against corrosion?
>  
> Javier Encinas
> Encinas & Associates
>



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