On Thu, 22 May 2008 15:21:41 -0700 (PDT), firstname.lastname@example.org
Reference aside, do you know what cutting torch is how it works?
A cutting torch *burns* the steel using a stream of oxygen that is
triggered by the lever, though the steel must be hot enough that it
will burn first. However, not all the steel is burned, some does fly
off as molten metal.
Melting a material changes its state. The state can be restored by
lowering its temperature.
Burning a material changes the material's composition usually
combining it with oxygen to form a new substance (iron oxide, for
exmaple) Once a material is burned lowering its temperature won't
And how many angels did you get to dance on the head of that pin?
You're engaged in sophistry. We are discussing steel columns and
house fires. For all intents and purposes there is no burning of a
steel column. But feel free to continue the debate - let me know when
you feel you're winning.
On Fri, 23 May 2008 07:56:33 -0700 (PDT), RicodJour
I always win, or so my wife tells me. For some reason I have to
believe her--I think it is because she told me so.
Steel columns in a house fire are not an issue. The house will be long
gone before they fail.
What we *were* discussing was whether cement in a column (of any
composition) adds strength, and if so, how much, and as well why add
Cement is added to a Lally column to prevent collapse or pinching
failures. Who cares what happens when the steel softens to the point
of failure? The game's over at that point regardless, the house will
be long gone, and the failure of other members of the structure will
make any column's ability to withstand fire a non-issue.
But, what the heck, let's argue onwards.
It also does provide much improved buckling resistance.
The PVC filled column is a very dumb idea unless an engineer has
computed the capacity of the column and sized it appropriately for the
Steel softens about 800F, if memory serves. Interior building fires can get
over 1300F at ceiling level. Twenty year old information, I'm likely wrong.
But the asbestos or cement around the steel helps in case of fire.
Although no one addressed the question, the geophysical stability of the
be of some measured consideration. Performance of the columns on soil
subject to liquefaction in a seismic event merits concern in the right
A first-hand look at the density of steel used in the recent rebuilds of
freeway overpass supports is amazing.
Whether the OP or owner has further interest in possible remedies for any
shortcomings in this case is a another question.
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