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RE: Fire rate TS

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The failure of a structural element due to fire exposure is a function of
the heat input, the amount of heat required to initiate failure, and the
material properties at elevated temperatures of the structural element.
Filling tube steel columns with water, antifreeze, and concrete has been
done for fire protection successfully on projects in Pittsburgh, Seattle,
and Kansas City among others.  Filling a tube steel shape increases the
amount of heat input required to raise the temperature of the material to
the point of failure.  The fill material acts as a heat sink.  It is not
that different than fireproofing (a misnomer) the outside of a column.
Either adding external protection or increasing the heat mass increases the
time it takes to initiate a failure.

The Lally column was conceived primarily to increase strength, and the
increased resistance for fire protection was quantified but is proprietary. 

Filling a tube steel shape with concrete has the added benefit of increasing
the strength of the member.

The down side is that it is not listed in the UL Handbook which contains all
of the canned recipes. To use a concrete filled column in a building would
probably require input from a fire protection engineer.  You can contact
Professor Spivak who is the Chair of the Department of Fire Protection
Engineering, University of Maryland 301-405-3992 for a reference. 

To get a listing in UL is a very expensive undertaking.
   
I believe that there was a paper presented at the AISC conference in New
Orleans on fire resistant filled structural tubes, and the ASCE is supposed
to publish a manual on fire protection sometime soon that will discuss
concrete filled tubes.

Harold Sprague
The Neenan Company
harold.sprague(--nospam--at)neenan.com


-----Original Message-----
From: Jim Price [mailto:jim_price_civil_engineer(--nospam--at)yahoo.com]
Sent: Tuesday, December 01, 1998 1:22 AM
To: seaint(--nospam--at)seaint.org
Subject: Re: Fire rate TS



Mark, I think you're barking up the wrong tree. The lally column that
you ask about relies on the steel tube for strength.  The concrete
inside the tube gives the tube column rigidity and more load carrying
ability.  If steel softens with heat, as we know it does, the steel
tube column will lose its strength and the load will be taken by the
concrete, and without the reinforcing steel, it will be considered to
fail.

It was a nice thought, but I doubt anyone can provide you with a fire
rating on the lally column.  You'll have to wrap it with gyp board or
cement, to protect the steel from the heat.


---Mike Brown <mike.brown(--nospam--at)cshqa.com> wrote:
>
> I have a quick question that I am hoping somebody can help me with: 
Is
> there a fire rating for concrete filled tube steel?  If so, where
can I
> get this information?  The UL listing only has assemblies for concrete
> filled pipes.
>  
> Thanks in advanced.
>  
> Michael K. Brown, P.E.
> CSHQA Engineers
> Boise, ID
> mike.brown(--nospam--at)cshqa.com
>