Disaster waiting to happen? Using PVC for deck supports???
Thomas G. Marshall
There was a person I was speaking to recently who was proud of what he
considered to be a very bright move on his part.
He had noticed that the lolly-columns in his basement had been filled with
cement prior to being used. He assumed that the strength of the support was
in the cement, and therefore concluded it was a good idea to try filling PVC
tubes and using those as posts (note-not as sonno-tubes, but as fully
structural support posts).
I pointed out that I thought that the strength of a lolly was in the steel,
and that the cement was there merely to ensure that it was never dented,
causing it to fold like an aluminum can. I was concerned that the first
major frost heave under his deck that is able to stress the ledger enough to
pull outward a small amount would cause his pvc+cement "posts" to break.
Was I right?
EXT
have much strength, especially if there is not a continuous large diameter
re-bar down the middle. I can see the PVC cracking in cold weather,
particularly if the top is able to soak up some water that freezes.
A 6" or 8" PVC tube with three or four re-bars, probably would be no more
than a vinyl coated concrete column, and look good compared to bare
concrete. The concrete will take most of the load. I can see the same
problems with freezing water however. It could be difficult to make a
connection with the foundation unless the post is run all the way down to
the footing.
"Thomas G. Marshall" <tgm2tothe...@replacetextwithnumber.hotmail.com>
wrote in message news:ib_Xj.134$ay2.84@trndny01...
RicodJour
I think you're right that there's cause for concern, I think you're
wrong about the failure mechanism unless the footings are seriously
sub-standard, and I think there's a lot of information left out. The
diameter of the PVC, whether it's Schedule 40 or 80 or even the thin
stuff that they use for drainage, how deep the footings are, how high
above grade the deck is, etc.
R
curt
>
> I think you're right that there's cause for concern, I think you're
> wrong about the failure mechanism unless the footings are seriously
> sub-standard, and I think there's a lot of information left out. The
> diameter of the PVC, whether it's Schedule 40 or 80 or even the thin
> stuff that they use for drainage, how deep the footings are, how high
> above grade the deck is, etc.
>
> R
If I remember correctly, Schedule 80 is called for on all deck support
posts.
Thomas G. Marshall
Implication question: Is PVC meeting schedule-80 requirements considered
acceptable for deck supports?
Thomas G. Marshall
...[snip]...
> The concrete in steel lolly columns is to help keep them from
> collapsing in a fire.
....so the preventing a dent thing is secondary, or not a concern...?
JoeSpareBedroom
wrote in message news:z51Yj.138$ay2.70@trndny01...
My interpretation is that the dent thing is completely irrelevant.
Dick Adams
> and therefore concluded it was a good idea to try
> filling PVC tubes and using those as posts
> (note-not as sonno-tubes, but as fully structural
> support posts).
Ignorance is bliss.
I used PVC for my mail box post. Went down 18 inches, carved
out a 3" foot lip, crisscrossed 8" bolt at 6" and 10", filled
with concrete and rebar. My mail box was getting knocked
down by cars sliding on ice.
Someone was knocking down mail boxes with a baseball bat.
The police found him when I told them to check for people
with forearms. This clown broke his forearm and his wrist.
But as a deck support, that's a joke.
Dick
Pete C.
There are code approved PVC pipe based deck support columns available.
The compressive strength of PVC pipe is tremendous as long as you keep
it from buckling. I once tested a 1' length of 4" sch40 PVC pipe in a
hydraulic press and it too over 30 tons of force before it started to
fail (Enerpac press with pressure gauge). The compressive strength of
concrete is also very high. Combined strength is more than adequate and
PVC handles cold pretty well also.
Matt Whiting
> fire.
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
anticipated loads.
Matt
Matt Whiting
No, preventing buckling is a significant advantage provided by filling a
steel column.
Matt
Matt Whiting
Your interpretation is incorrect.
Matt
JoeSpareBedroom
news:V42Yj.35383$941....@fe101.usenetserver.com...
OK.
Glenn
"Thomas G. Marshall"
<tgm2tothe...@replacetextwithnumber.hotmail.com>
wrote in message news:ib_Xj.134$ay2.84@trndny01...
>
>
> There was a person I was speaking to recently who was
> proud of what he considered to be a very bright move
> on his part.
>
> He had noticed that the lolly-columns in his basement
> had been filled with cement prior to being used. He
> assumed that the strength of the support was in the
> cement, and therefore concluded it was a good idea to
> try filling PVC tubes and using those as posts
> (note-not as sonno-tubes, but as fully structural
> support posts).
Interesting concept. Never did that but with 2 or 3
rebar in it, maybe a #8 right up the middle, it seems
like just a neat form that you don't have to remove.
Glenn
>
> No, preventing buckling is a significant advantage
> provided by filling a steel column.
>
> Matt
Whoa, if you are using a steel column, why the
concrete? Sky scrapers sit on steel columns with out
concrete in them. What am I missing?
Matt Whiting
I'd hardly call it tremendous. 8300 psi exceed most standard concrete,
although high strength concrete is available now that substantially
exceeds this value. And this falls FAR short of even standard A36 steel.
Pete C.
8300 psi? I come up with more like 37,500 psi since this was 4" dia sch
40 PVC pipe with no filling i.e. 60,000# load on something like 1.6
square inches of PVC total.
Lou
doing. Not to mention how you would attach them without making
it look jerry rigged. Even if you got past those two items, what would
you make the rest of the deck out of to look right? I suppose if your
only
going 12" off the ground that it wouldn't matter but it sure sounds
like
your taking a step backwards.
Lou
Lou
> >> The concrete in steel lolly columns is to help keep them from collapsing in a
> >> fire.
>
> >It also does provide much improved buckling resistance.
>
Check the temp that would cause steel to buckle.
Now see what happens to concrete at that temp.
Lou
RicodJour
> On Sun, 18 May 2008 18:28:48 -0400, Matt Whiting <whit...@epix.net> wrote:
> >Thomas G. Marshall wrote:
> >> sa...@dog.com said something like:
>
> >>> collapsing in a fire.
>
> >> ....so the preventing a dent thing is secondary, or not a concern...?
>
> >No, preventing buckling is a significant advantage provided by filling a
> >steel column.
>
> columns with cement is to protect the columns from buckling in a FIRE.
In a wood framed building? I guess if the fire started at the base of
the column that might be a good argument, but in any real situation
the house would be engulfed in flames long before the plastic
temperature of the steel was reached.
The concrete fill is to prevent buckling, partially from being dented,
but also to prevent localized failure which can occur at lower loads
than the straight compressive strength of the material(s) would
indicate.
http://en.wikipedia.org/wiki/Buckling
R
Stormin Mormon
for compressive loads (such as columns in the cellar). Steel is good for
stretching loads (hanging a bridge from a frame).
If your friend's use of concrete is to support weight, it may work very
well. Concrete often has reinforcing bar, or rebar. This steel helps to
combine the compression strength of concrete with the stretching strength of
steel.
--
Christopher A. Young
Learn more about Jesus
www.lds.org
.
"Thomas G. Marshall" <tgm2tothe...@replacetextwithnumber.hotmail.com>
wrote in message news:ib_Xj.134$ay2.84@trndny01...
Stormin Mormon
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.
--
Christopher A. Young
Learn more about Jesus
www.lds.org
.
<sa...@dog.com> wrote in message
news:bdj134hkp6cp5rt95...@4ax.com...
>> The concrete in steel lolly columns is to help keep them from collapsing
>> in a
>> fire.
>
>It also does provide much improved buckling resistance.
>
Yes, buckling that would be caused by the heat of a FIRE.
PeterD
Perhaps four years of engineering school? Or even two semesters of
structural member strength? <g>
Glenn
"PeterD" <pet...@hipson.net> wrote in message
news:irt234959tqo2qgb1...@4ax.com...
Cute. When you have 1300 degrees on the wood it's
supporting, the column is the last thing I will be
concerned with. In a total of some 45 years of
construction, I have never seen this in my neck of the
woods. Perhaps some are over educated? <g>
Thomas G. Marshall
This makes sense to me, though I'm hardly as versed in structural analysis
as the other denisins of this ng. Fire seems a concern, though secondary,
only because the plasticity of steel could never be reached in a basement
without the rest of the house already having been reduced to dust. Or so it
seems to me. {shrug}
mkir...@rochester.rr.com
> Someone was knocking down mail boxes with a baseball bat.
> The police found him when I told them to check for people
> with forearms. This clown broke his forearm and his wrist.
Good thing the clown was dumb as a the post he broke his arm on
because if he'd had a lick of smarts at all he would've sued you for
the injuries he sustained trying to bash in your mailbox... and he
would've won. You're lucky.
A friend of mine put boulders in his front yard because drunk drivers
had missed the corner and ended up in his front yard on several
occasions, and had hit both his house and his travel trailer at least
once. The insurance company gave him 48 hours to have the boulders
removed or they'd drop his policy. Long and short of it was, the
boulders were a willful admission of wrongdoing/negligence in a
lawsuit because they were put there to protect the house from drunk
drivers. He could say they were decorative all he wanted, all they had
to do in court was point out that the boulders were placed there AFTER
the drunk hit his trailer, and he'd lose.
Lou
Well I'm no attorney but, that doesn't sound right. A drunk driver
doesn't premeditate
getting drunk and running into a house so therefore creates an
accident. An idiot
smashing mailboxes does premeditate the conditions, planning and
carrying out
the plan to destroy private property. He could have sued but my bet
is that it would
have backfired.
Lou
Matt Whiting
> columns with cement is to protect the columns from buckling in a FIRE.
It also adds tremendously to normal buckling resistance, not just
buckling resistance due to fire reducing the capacity of the material.
http://www.aisc.org/Content/ContentGroups/Documents/Connections_IV_Proceedings/51.pdf
Matt Whiting
> On Sun, 18 May 2008 18:28:11 -0400, Matt Whiting <whi...@epix.net> wrote:
>
>> sa...@dog.com wrote:
>>> On Sun, 18 May 2008 18:02:54 GMT, "Thomas G. Marshall"
>>> <tgm2tothe...@replacetextwithnumber.hotmail.com> wrote:
>>>
>>>> There was a person I was speaking to recently who was proud of what he
>>>> considered to be a very bright move on his part.
>>>>
>>>> He had noticed that the lolly-columns in his basement had been filled with
>>>> cement prior to being used. He assumed that the strength of the support was
>>>> in the cement, and therefore concluded it was a good idea to try filling PVC
>>>> tubes and using those as posts (note-not as sonno-tubes, but as fully
>>>> structural support posts).
>>>>
>>>> I pointed out that I thought that the strength of a lolly was in the steel,
>>>> and that the cement was there merely to ensure that it was never dented,
>>>> causing it to fold like an aluminum can. I was concerned that the first
>>>> major frost heave under his deck that is able to stress the ledger enough to
>>>> pull outward a small amount would cause his pvc+cement "posts" to break.
>>>>
>>>> Was I right?
>>>>
>>>>
>>> The concrete in steel lolly columns is to help keep them from collapsing in a
>>> fire.
>> It also does provide much improved buckling resistance.
>>
>
No, buckling caused by heavy load as well. A column doesn't need fire
to buckle.
Matt
Matt Whiting
Material properties don't depend on the size of the pipe. Did you even
open the reference I provided? Do you understand MATERIAL properties?
Matt
Edward Hennessey
M:
Although no one addressed the question, the geophysical stability of the
location would
be of some measured consideration. Performance of the columns on soil
subject to liquefaction in a seismic event merits concern in the right
circumstances.
A first-hand look at the density of steel used in the recent rebuilds of
L.A.
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.
Regards,
Edward Hennessey
Pete C.
Do you understand that under testing in my 50T press, it took a load of
~37,500 PSI on the 1' length of 4" sch 40 PVC pipe before it failed?
Material properties are irrelevant, that was the actual result of the
test I noted.
Tom Cular
members, not within a pipe or tube.
To make it simple, take a look at a typical pipe pile, driven empty, then
filled with concrete, with a circular cage reinforcing only in the upper
section (top 20-30'), a vertical bar or two near the center does nothing.
As Matt and Rico have stated the concrete fill is to resist buckling.
Tom
"Stormin Mormon" <cayoung61**spamblock##@hotmail.com> wrote in message
news:48316ee6$0$7042$4c36...@roadrunner.com...
Matt Whiting
37,500 psi is a pressure, not a load. Material properties are not only
relevant, they are essential to almost all structural engineering
calculations (I know as I have a masters in civil/structural). And the
behavior of a short column is MUCH different than a long column. Ever
heard of Euler?
A nearly pure compression test (which is what a 1' long 4" pipe
comprises) has almost no relevance to the case of a column that has a
substantially different slenderness ratio and thus subject to a buckling
failure mode as well as possible bending moments due to eccentric loading.
I didn't see a column length in the OP, but when "basement" is the
description rather than "crawl space" it is likely that the length is at
least 6' and possibly 8' or even more. This is far from being a 1'
column. Concrete filled PVC could work if sized properly, but using the
same size as the existing steel column is a fool's errand. Again, the
OP didn't mention the size of either the steel or the PVC, but I'll bet
there were likely nearly the same size. If that is the case, then the
PVC is almost certainly inadequate, unless the steel column was grossly
oversized for the required load.
Matt
tra...@optonline.net
> Fire protection of structural steel is placed on the exterior of the
> members, not within a pipe or tube.
>
> To make it simple, take a look at a typical pipe pile, driven empty, then
> filled with concrete, with a circular cage reinforcing only in the upper
> section (top 20-30'), a vertical bar or two near the center does nothing.
>
> As Matt and Rico have stated the concrete fill is to resist buckling.
>
> Tom
>
>
> news:48316ee6$0$7042$4c36...@roadrunner.com...
>
>
>
> > When I was in college, so many years ago. We learned that cement is strong
> > for compressive loads (such as columns in the cellar). Steel is good for
> > stretching loads (hanging a bridge from a frame).
>
> > If your friend's use of concrete is to support weight, it may work very
> > well. Concrete often has reinforcing bar, or rebar. This steel helps to
> > combine the compression strength of concrete with the stretching strength
> > of
> > steel.
>
> > --
> > Christopher A. Young
> > Learn more about Jesus
> > www.lds.org
> > .
>
> > "Thomas G. Marshall"
> > wrote in messagenews:ib_Xj.134$ay2.84@trndny01...
>
> > There was a person I was speaking to recently who was proud of what he
> > considered to be a very bright move on his part.
>
> > He had noticed that the lolly-columns in his basement had been filled with
> > cement prior to being used. He assumed that the strength of the support
> > was
> > in the cement, and therefore concluded it was a good idea to try filling
> > PVC
> > tubes and using those as posts (note-not as sonno-tubes, but as fully
> > structural support posts).
>
> > I pointed out that I thought that the strength of a lolly was in the
> > steel,
> > and that the cement was there merely to ensure that it was never dented,
> > causing it to fold like an aluminum can. I was concerned that the first
> > major frost heave under his deck that is able to stress the ledger enough
> > to
> > pull outward a small amount would cause his pvc+cement "posts" to break.
>
>
> - Show quoted text -
And I would submit that it does a lot more than just provide the
buckling resistance. Concrete is widely used to form structural
support to hold up buildings, bridges, etc. Even in this deck
example, what are the footers made of? They are essentially
cylindrical concrete pillars. So, while the concrete does keep the
steel pipes in a lolly column from buckling, which is clearly
important, the concrete also carries some of the weight directly. If
instead of concrete, you had some other means to keep the column from
buckling, say an internal criss cross web of little rods, I would say
the concrete filled lolly would carry substantially more weight.
Pete C.
It is both.
> Material properties are not only
> relevant, they are essential to almost all structural engineering
> calculations (I know as I have a masters in civil/structural).
And what I presented was not a structural engineering calculation it was
simply the results of a real world test that point out that sch 40 PVC
pipe is a lot stronger than most people think.
> And the
> behavior of a short column is MUCH different than a long column. Ever
> heard of Euler?
No kidding, and again, I didn't present any structural engineering info,
simply actual results of a real world test showing the surprising
strength of PVC pipe.
>
> A nearly pure compression test (which is what a 1' long 4" pipe
> comprises) has almost no relevance to the case of a column that has a
> substantially different slenderness ratio and thus subject to a buckling
> failure mode as well as possible bending moments due to eccentric loading.
Right, but again, I didn't present anything to the contrary. I indicated
that code approved PVC pipe based deck supports were available, which
they are, and an example showing that PVC pipe is stronger than people
think.
>
> I didn't see a column length in the OP, but when "basement" is the
> description rather than "crawl space" it is likely that the length is at
> least 6' and possibly 8' or even more. This is far from being a 1'
> column. Concrete filled PVC could work if sized properly, but using the
> same size as the existing steel column is a fool's errand. Again, the
> OP didn't mention the size of either the steel or the PVC, but I'll bet
> there were likely nearly the same size. If that is the case, then the
> PVC is almost certainly inadequate, unless the steel column was grossly
> oversized for the required load.
Probably, and I didn't suggest the OP's scenario was proper or safe. I
simply noted that "Using PVC for deck supports" as in the subject line
is possible and code approved if done properly, and not a "Disaster
waiting to happen" as was also in the subject line. Can't seem to find a
link to the product at the moment. Believe I read about it in Fine
Homebuilding or perhaps JLC.
CWatters
<sa...@dog.com> wrote in message
news:39j134h08gs30kb4k...@4ax.com...
> On Sun, 18 May 2008 18:28:48 -0400, Matt Whiting <whi...@epix.net> wrote:
>
>>Thomas G. Marshall wrote:
>>>> collapsing in a fire.
>>>
>>>
>>>
>>
>>No, preventing buckling is a significant advantage provided by filling a
>>steel column.
>>
>>Matt
>
> Uh, yes. And the buckling it prevents would be the result of fire. Filling
> the
> columns with cement is to protect the columns from buckling in a FIRE.
>
>
PVC burns doesn't it?
CWatters
"Thomas G. Marshall" <tgm2tothe...@replacetextwithnumber.hotmail.com>
wrote in message news:ib_Xj.134$ay2.84@trndny01...
>
>
> considered to be a very bright move on his part.
>
> He had noticed that the lolly-columns in his basement had been filled with
> cement prior to being used. He assumed that the strength of the support
> was in the cement, and therefore concluded it was a good idea to try
> filling PVC tubes and using those as posts (note-not as sonno-tubes, but
> as fully structural support posts).
For what?
CJT
So does steel.
--
The e-mail address in our reply-to line is reversed in an attempt to
minimize spam. Our true address is of the form che...@prodigy.net.
jimbobm...@verizon.net
> CWatters wrote:
> > <sa...@dog.com> wrote in message
> >news:39j134h08gs30kb4k...@4ax.com...
>
>
> >>>Thomas G. Marshall wrote:
>
> >>>>sa...@dog.com said something like:
>
> >>>>...[snip]...
>
> >>>>>The concrete in steel lolly columns is to help keep them from
> >>>>>collapsing in a fire.
>
> >>>>....so the preventing a dent thing is secondary, or not a concern...?
>
> >>>No, preventing buckling is a significant advantage provided by filling a
> >>>steel column.
>
> >>>Matt
>
> >>Uh, yes. And the buckling it prevents would be the result of fire. Filling
> >>the
> >>columns with cement is to protect the columns from buckling in a FIRE.
>
> > PVC burns doesn't it?
>
> So does steel.
>
> --
> The e-mail address in our reply-to line is reversed in an attempt to
>
> - Show quoted text -
Steel burns? I guess I learned something new today.
JoeSpareBedroom
news:3a346fe4-3759-4f70...@w5g2000prd.googlegroups.com...
============
Anything will burn at the right temp.
jimbobm...@verizon.net
> <jimbobmitch...@verizon.net> wrote in message
>
> - Show quoted text -
So there's no difference between burning and melting?
CJT
Sure there is. Steel will do either (or both) depending on the conditions.
Stormin Mormon
--
Christopher A. Young
Learn more about Jesus
www.lds.org
.
<mkir...@rochester.rr.com> wrote in message
news:4e58ec38-9aef-4ea1...@27g2000hsf.googlegroups.com...
HerHusband
> with cement prior to being used. He assumed that the strength of the
> support was in the cement, and therefore concluded it was a good idea
> to try filling PVC tubes and using those as posts (note-not as
> sonno-tubes, but as fully structural support posts).
> I was concerned that the first major frost heave under his deck that
> is able to stress the ledger enough to pull outward a small amount
> would cause his pvc+cement "posts" to break.
First, I'm no engineer, but a few thoughts did come to mind...
You didn't mention the height of the deck or the span between support
posts, but in general there shouldn't be much of a load on a deck (no
walls, ceilings, roofing, etc.). Assuming a typical residential
situation, of course.
If the post footings are below the frostline in the area, they shouldn't
heave anyway should they? But even so, PVC is fairly flexible, and even
concrete flexes a small amount. With "typical" structural movements, I
don't see this being an issue. They're not gonna "snap like twigs" at the
first sign of stress.
If the PVC is filled with concrete, I don't see why it would be any
different than a cardboard sonotube, except you would not need to remove
the PVC after the pour. Even if the PVC doesn't offer any structural
support, the concrete piers inside the PVC should support the weight of
the deck.
If you're concerned about "flex" in the column, you should install rebar
reinforcement whether you're using PVC, a sonotube, or even building a
square box for the concrete pier.
Unless this is a second story deck, or one perched out over a hillside,
"most" decks only sit a foot or two off the ground and are supported by
multiple pier posts. I doubt there will be any significant sideways loads
to buckle the columns.
A recent article in Fine Homebuilding showed a system that used PVC pipe
to support a small shed (with no concrete). If it works for a shed, it's
bound to be adequate for a deck.
Unlike a steel post, PVC won't rust. However, regular PVC will be damaged
by ultraviolet light from the sun, and will get brittle. You could avoid
this by using grey PVC conduit which has protection against ultraviolet
light.
Around here, many decks are built with nothing more than a 4x4 post
sitting in precast concrete pier blocks sitting on the ground and have
lasted for decades. Also, many mobile homes sit on concrete blocks that
are just dry stacked piers with no reinforcement (ours was setup that way
for 13 years, with one end nearly four feet off the ground, and we
survived two earthquakes with no problems). These are obviously UNDER
engineered situations, but it's also possible to OVER engineer the
support for a deck as well...
Anthony
scrumble
> RicodJour said something like:
>> On May 18, 8:45 pm, sa...@dog.com wrote:
>>> On Sun, 18 May 2008 18:28:48 -0400, Matt Whiting <whit...@epix.net>
>>> wrote:
>>>> Thomas G. Marshall wrote:
>>>>> sa...@dog.com said something like:
>>>>>> The concrete in steel lolly columns is to help keep them from
>>>>>> collapsing in a fire.
>>>>> ....so the preventing a dent thing is secondary, or not a
>>>>> concern...?
>>>> No, preventing buckling is a significant advantage provided by
>>>> filling a steel column.
>>> Uh, yes. And the buckling it prevents would be the result of fire.
>>> Filling the columns with cement is to protect the columns from
>>> buckling in a FIRE.
>> In a wood framed building? I guess if the fire started at the base of
>> the column that might be a good argument, but in any real situation
>> the house would be engulfed in flames long before the plastic
>> temperature of the steel was reached.
>>
>> The concrete fill is to prevent buckling, partially from being dented,
>> but also to prevent localized failure which can occur at lower loads
>> than the straight compressive strength of the material(s) would
> only because the plasticity of steel could never be reached in a basement
> without the rest of the house already having been reduced to dust. Or so it
> seems to me. {shrug}
The problem with fire and steel beams/columns isn't so much from
structural weakness when the steel becomes hot, although that would be a
concern where the intention is to contain the fire for a length of time,
but more from the actual expansion of the steel, either from it pushing
other structural elements, or itself buckling when the expansion at both
ends is restricted.
--
scrum
(\_/) Procrastinator bunny says:
( . .) "I'll conquer the internets tomorrow"
C(")(")
scrumble
> On Sun, 18 May 2008 18:28:11 -0400, Matt Whiting <whi...@epix.net> wrote:
>
>> sa...@dog.com wrote:
>>> <tgm2tothe...@replacetextwithnumber.hotmail.com> wrote:
>>>
>>>> There was a person I was speaking to recently who was proud of what he
>>>> considered to be a very bright move on his part.
>>>>
>>>> cement prior to being used. He assumed that the strength of the support was
>>>> in the cement, and therefore concluded it was a good idea to try filling PVC
>>>> tubes and using those as posts (note-not as sonno-tubes, but as fully
>>>> structural support posts).
>>>>
>>>> and that the cement was there merely to ensure that it was never dented,
>>>> pull outward a small amount would cause his pvc+cement "posts" to break.
>>>>
>>>>
>>>>
>>> The concrete in steel lolly columns is to help keep them from collapsing in a
>>> fire.
>>
>
> Yes, buckling that would be caused by the heat of a FIRE.
>
>
But surely if that was the only reason for the concrete it would far
easier and cheaper just to coat the steel with an intumescent paint?
Thomas G. Marshall
I agree, but further, this is an odd "argument".
I look also at the things that might happen in a basement. Heavy things
could be moved around and dent the column. It would take a hell of a whack
to do that, but it seems to me that filling the thing with concrete is an
incredibly cheap way of ensuring that a column doesn't collapse in such an
[albeit rare] event.
Further, having seen what my 3 1/2 and 1 1/2 year old consider game for
smacking with a rock or hammer, I'm thinking that substantially removing the
notion of disaster with concrete innards is a great idea. And I can imagine
a young person able to swing a sledge hammer thinking it a "funny idea" to
send a shock wave through the house, thinking perhaps that the lolies were
solid steel or somesuch.
Thomas G. Marshall
...[snip]...
> I didn't see a column length in the OP, but when "basement" is the
> description rather than "crawl space" it is likely that the length is
> at least 6' and possibly 8' or even more. This is far from being a 1'
> column. Concrete filled PVC could work if sized properly, but using
> the same size as the existing steel column is a fool's errand. Again, the
> OP didn't mention the size of either the steel or the PVC, but I'll
> bet there were likely nearly the same size. If that is the case,
> then the PVC is almost certainly inadequate, unless the steel column
> was grossly oversized for the required load.
In my original post I believe I was clear in using the steel column
reference only in what the person I met had used as his reasoning for
filling them with concrete.
I pointed out that HE was under the impression that the strength of the
steel column was primarily the concrete within it, and he believed that the
steel was a mere form for it. Hence he figured that using nearly anything
as a form, e.g. PVC, would be enough for the deck supports.
I am not sure of the diameter. I am not sure of the length. I am not sure
that they were also the footings (though I hope not, since I doubt he
understands the notion of "big feet" and I doubt he was using hugely wide
posts).
But I have seen concrete cracks in all kinds of things, and I can't help but
imagine a crack going clear through one of those things causing a disaster.
YMMV {shrug}
Thomas G. Marshall
I mentioned the deck in the subject and in the paragraph you snipped. But I
was not as clear as I could be: he was using them as the posts.
--
Onedoctortoanother:"Ifthisismyrectalthermometer,wherethehell'smypen???"
Matt Whiting
> On Wed, 21 May 2008 21:18:25 GMT, "Thomas G. Marshall"
> THE CODE in many places.
What is a lolly column? Is that anything like a lally column?
What place has this in the fire code?
Here is a reference that clearly states that the main purpose for
filling the columns is strength. And it discusses that the concrete can
actually be detrimental in a fire in certain conditions although it
certainly is beneficial in other conditions.
Bottom line is that filling the columns with concrete is not done
primarily for reasons of fire resistance. It is for strength first and
fire resistance is a nice fringe benefit.
Matt
George
when you squeeze the lever on a cutting torch.
jimbobm...@verizon.net
> CJT wrote:
>
> - Show quoted text -
That, imho, is a perfect example of melting, not "burning"
Nate Nagel
some of it does indeed burn. if you don't believe me, hold a match
under a wad of 0000 steel wool. Outside, or in a deep sink...
nate
--
replace "roosters" with "cox" to reply.
http://members.cox.net/njnagel
PeterD
wrote:
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
restore it.
RicodJour
> On Thu, 22 May 2008 15:21:41 -0700 (PDT), jimbobmitch...@verizon.net
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.
R
jimbobm...@verizon.net
>
> - Show quoted text -
Really, I sit corrected--steel does burn!
PeterD
<rico...@worldemail.com> wrote:
> 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.
>
>R
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.
That said...
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.
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.
Matt Whiting
> concrete in those columns. That's why the building fire safety codes insist on
> them being there.
I've seen two claims of fire codes requiring concrete fill, yet I've
seen no reference posted to a fire code that does require that in
residential construction. Reference??
George
>
>>>>>> - Show quoted text -
>>>>> Steel burns? I guess I learned something new today.
>>>>> ============
>>>>> Anything will burn at the right temp.- Hide quoted text -
>>>>> - Show quoted text -
>>>> So there's no difference between burning and melting?
>>> Sure there is. Steel will do either (or both) depending on the conditions.
>> Exactly, the perfect example is to consider what is actually happening
>> when you squeeze the lever on a cutting torch.- Hide quoted text -
>>
>> - Show quoted text -
>
>
> That, imho, is a perfect example of melting, not "burning"
>
> http://www.newton.dep.anl.gov/askasci/gen06/gen06008.htm
>
the lever is supporting.
Matt Whiting
As I suspected ... you are just making up stuff.