info
Google Groups no longer supports new Usenet posts or subscriptions. Historical content remains viewable.
Dismiss
Weight bearing strength of 5 ft. of black iron pipe
23,880 views
Skip to first unread message
Maddog
Jul 9, 2015, 10:18:04 PM7/9/15
to
If I fully support 60 in. of 1-1/2 inch diameter black iron pipe (bought
at Lowes or Home Depot), approximately how much weight can it support in
the center before it begins to bend more than 3/4 in. - 1 in. ?
--
posted from
http://www.polytechforum.com/metalworking/weight-bearing-strength-of-5-ft-of-black-iron-pipe-617688-.htm
using PolytechForum's Web, RSS and Social Media Interface to
rec.crafts.metalworking and other engineering groups
at Lowes or Home Depot), approximately how much weight can it support in
the center before it begins to bend more than 3/4 in. - 1 in. ?
--
posted from
http://www.polytechforum.com/metalworking/weight-bearing-strength-of-5-ft-of-black-iron-pipe-617688-.htm
using PolytechForum's Web, RSS and Social Media Interface to
rec.crafts.metalworking and other engineering groups
whit3rd
Jul 10, 2015, 12:13:10 AM7/10/15
to
On Thursday, July 9, 2015 at 7:18:04 PM UTC-7, Maddog wrote:
> If I fully support 60 in. of 1-1/2 inch diameter black iron pipe (bought
> at Lowes or Home Depot), approximately how much weight can it support in
> the center before it begins to bend more than 3/4 in. - 1 in. ?
Does 'fully support' mean support all along the length? Or point supports at
> If I fully support 60 in. of 1-1/2 inch diameter black iron pipe (bought
> at Lowes or Home Depot), approximately how much weight can it support in
> the center before it begins to bend more than 3/4 in. - 1 in. ?
each end? Or vise-like clamping of the ends?
Does the pipe have an axis-direction load and you're concerned with it buckling?
Is it horizontal with a single point load (weight) in the center?
Is it horizontal with a uniform load (like a row of bricks) all along its length?
Lowes has cast-iron pipe in 2" diameter, is that what you mean?
Steel pipe, often called "black iron", is available in outer diameters of 1.315" (one inch nominal),
and 1.660" (1 1/4 inch nominal) and 1.9" (which is 1 1/2 inch nominal). Do
you mean one of those? Lowes web site mentions they carry the 1 1/4" size.
Finally, steel pipe is available in Schedule 40, 80, or 160; for 1 1/4" those
are 2.3 lbs/foot, 3 lbs/foot, and 3.8 lbs/foot. Do you have a preference?
Carl Ijames
Jul 10, 2015, 12:32:03 AM7/10/15
to
I used data for steel pipe, I'm not a professional engineer, this is worth
what you are paying, yadda, yadda. For 1-1/2" schedule 40 steel pipe,
1.900" OD x 1.610" ID, with a free span of 60" and the ends simply supported
such as sitting on bricks or boards, a load of 1000 lbs in the center of the
span will cause a deflection of 0.50" and a maximum stress in the steel of
46,000 psi. A typical yield strength for mild steel is 40-50,000 psi so at
that load the pipe will either be right on the edge of yielding or will have
already yielded some and won't be straight when you remove the load. A
typical safety factor would be to allow a factor of three or more (3 if it
is part of a structure and the load is mostly dead weight but could be
someone walking on it, ten or more if this is the only loaded beam and it's
supporting a bouncy load and people will die if it fails), and the
deflection and stress are directly proportional to the load so if the load
was 1000 lbs/3=333 lbs the deflection would be 0.50"/3=0.167" and the
maximum stress would be 46,000 psi/3=15,333 psi. Black iron is probably a
little weaker but if you have any sense you will use a large enough safety
factor that it won't matter.
-----
Regards,
Carl Ijames
"Maddog" wrote in message
news:46158$559f2b5a$43de0cc0$16...@news.flashnewsgroups.com...
what you are paying, yadda, yadda. For 1-1/2" schedule 40 steel pipe,
1.900" OD x 1.610" ID, with a free span of 60" and the ends simply supported
such as sitting on bricks or boards, a load of 1000 lbs in the center of the
span will cause a deflection of 0.50" and a maximum stress in the steel of
46,000 psi. A typical yield strength for mild steel is 40-50,000 psi so at
that load the pipe will either be right on the edge of yielding or will have
already yielded some and won't be straight when you remove the load. A
typical safety factor would be to allow a factor of three or more (3 if it
is part of a structure and the load is mostly dead weight but could be
someone walking on it, ten or more if this is the only loaded beam and it's
supporting a bouncy load and people will die if it fails), and the
deflection and stress are directly proportional to the load so if the load
was 1000 lbs/3=333 lbs the deflection would be 0.50"/3=0.167" and the
maximum stress would be 46,000 psi/3=15,333 psi. Black iron is probably a
little weaker but if you have any sense you will use a large enough safety
factor that it won't matter.
-----
Regards,
Carl Ijames
"Maddog" wrote in message
news:46158$559f2b5a$43de0cc0$16...@news.flashnewsgroups.com...
Jim Wilkins
Jul 10, 2015, 7:45:31 AM7/10/15
to
"Carl Ijames" <carl.i...@XXverizon.net> wrote in message
news:mnnhp...@news7.newsguy.com...
I recently investigated and ran the numbers for 2" pipe column
strength, and found warnings that water pipe steel isn't rated for
structures and its yield point could be as low as 25,000 PSI.
news:mnnhp...@news7.newsguy.com...
strength, and found warnings that water pipe steel isn't rated for
structures and its yield point could be as low as 25,000 PSI.
Joe Gwinn
Jul 10, 2015, 8:33:33 AM7/10/15
to
In article <mnnhp...@news7.newsguy.com>, Carl Ijames
first.
Joe Gwinn
<carl.i...@XXverizon.net> wrote:
> I used data for steel pipe, I'm not a professional engineer, this is worth
> what you are paying, yadda, yadda. For 1-1/2" schedule 40 steel pipe,
> 1.900" OD x 1.610" ID, with a free span of 60" and the ends simply supported
> such as sitting on bricks or boards, a load of 1000 lbs in the center of the
> span will cause a deflection of 0.50" and a maximum stress in the steel of
> 46,000 psi. A typical yield strength for mild steel is 40-50,000 psi so at
> that load the pipe will either be right on the edge of yielding or will have
> already yielded some and won't be straight when you remove the load. A
> typical safety factor would be to allow a factor of three or more (3 if it
> is part of a structure and the load is mostly dead weight but could be
> someone walking on it, ten or more if this is the only loaded beam and it's
> supporting a bouncy load and people will die if it fails), and the
> deflection and stress are directly proportional to the load so if the load
> was 1000 lbs/3=333 lbs the deflection would be 0.50"/3=0.167" and the
> maximum stress would be 46,000 psi/3=15,333 psi. Black iron is probably a
> little weaker but if you have any sense you will use a large enough safety
> factor that it won't matter.
Also need to do a buckling analysis, as pipe in bending usually buckles
> I used data for steel pipe, I'm not a professional engineer, this is worth
> what you are paying, yadda, yadda. For 1-1/2" schedule 40 steel pipe,
> 1.900" OD x 1.610" ID, with a free span of 60" and the ends simply supported
> such as sitting on bricks or boards, a load of 1000 lbs in the center of the
> span will cause a deflection of 0.50" and a maximum stress in the steel of
> 46,000 psi. A typical yield strength for mild steel is 40-50,000 psi so at
> that load the pipe will either be right on the edge of yielding or will have
> already yielded some and won't be straight when you remove the load. A
> typical safety factor would be to allow a factor of three or more (3 if it
> is part of a structure and the load is mostly dead weight but could be
> someone walking on it, ten or more if this is the only loaded beam and it's
> supporting a bouncy load and people will die if it fails), and the
> deflection and stress are directly proportional to the load so if the load
> was 1000 lbs/3=333 lbs the deflection would be 0.50"/3=0.167" and the
> maximum stress would be 46,000 psi/3=15,333 psi. Black iron is probably a
> little weaker but if you have any sense you will use a large enough safety
> factor that it won't matter.
first.
Joe Gwinn
Jim Wilkins
Jul 10, 2015, 9:06:41 AM7/10/15
to
"Joe Gwinn" <joeg...@comcast.net> wrote in message
news:100720150833319416%joeg...@comcast.net...
Or spread out the load with pipe hangers or muffler clamps.
I've found useful clamps for water pipe at a chain link fence dealer.
Take a sample because the nominal sizing numbers are different, and
neither match the measured diameter.
The Dillon load cell I used to proof test my homebrew hoisting gear no
longer returns to zero, perhaps it had already started to crack when I
bought it for 5% of list price. I didn't take it over half scale. So
far this appears to be an adequate, fairly inexpensive (compared to
injuries) replacement:
http://www.amazon.com/Sun-king-precision-2000LBS-Aluminum-Digital/dp/B00WO29ZGM
-jsw
news:100720150833319416%joeg...@comcast.net...
I've found useful clamps for water pipe at a chain link fence dealer.
Take a sample because the nominal sizing numbers are different, and
neither match the measured diameter.
The Dillon load cell I used to proof test my homebrew hoisting gear no
longer returns to zero, perhaps it had already started to crack when I
bought it for 5% of list price. I didn't take it over half scale. So
far this appears to be an adequate, fairly inexpensive (compared to
injuries) replacement:
http://www.amazon.com/Sun-king-precision-2000LBS-Aluminum-Digital/dp/B00WO29ZGM
-jsw
Maddog
Jul 10, 2015, 3:18:04 PM7/10/15
to
replying to Jim Wilkins , Maddog wrote:
right. This Schd. 40 Pipe will be horizontal with each end sitting in a
slotted wood block. There is no axial load, and nothing inside the pipe.
It will only be used overhead in my garage as an occasional lifting point
or sling support. Stationary loads, with no bouncing or swinging, and
usually load hung from 2 points at 1-2 feet apart rather than just at
center (worst case). I know the pipe is not designed for or intended for
such use, but it is simple & inexpensive.
Sounds like it will work for my intended loads of 500 lbs. or less.
My only question still remaining is if the galvanized pipe would be a bit
stronger than the black iron pipe? Just a few bucks more. I'll mesasure to
see if wall thickness is any different.
Greg
> muratlanne wrote:
>
> "Carl Ijames" <carl.i...@XXverizon.net> wrote in message
> news:mnnhp...@news7.newsguy.com...
>
> "Carl Ijames" <carl.i...@XXverizon.net> wrote in message
> news:mnnhp...@news7.newsguy.com...
> I recently investigated and ran the numbers for 2" pipe column
> strength, and found warnings that water pipe steel isn't rated for
> structures and its yield point could be as low as 25,000 PSI.
Thanks gentlemen! All great & valuable responses. Carl's assumptions are
> strength, and found warnings that water pipe steel isn't rated for
> structures and its yield point could be as low as 25,000 PSI.
right. This Schd. 40 Pipe will be horizontal with each end sitting in a
slotted wood block. There is no axial load, and nothing inside the pipe.
It will only be used overhead in my garage as an occasional lifting point
or sling support. Stationary loads, with no bouncing or swinging, and
usually load hung from 2 points at 1-2 feet apart rather than just at
center (worst case). I know the pipe is not designed for or intended for
such use, but it is simple & inexpensive.
Sounds like it will work for my intended loads of 500 lbs. or less.
My only question still remaining is if the galvanized pipe would be a bit
stronger than the black iron pipe? Just a few bucks more. I'll mesasure to
see if wall thickness is any different.
Greg
Carl Ijames
Jul 10, 2015, 3:38:06 PM7/10/15
to
You say "Stationary loads, with no bouncing or swinging, and
into existence in position, not that they are lifted off the floor. It's
the jerking and bouncing during that lift that make this a live load and
require at least a factor of 3-5 safety factor. Even if you don't see it,
it is happening, and what if something sticks or someone walks by and gives
it a swing just for fun? Yes, spreading the attachment points on the pipe
help, but I wouldn't lift more than maybe 200 lbs with 1.5" sched 40 pipe so
I think you should go on up to 2" galvanized steel pipe, and maybe even
schedule 80 instead of 40. Spend an extra $5 and have a LOT more peace of
mind later. If you do insist on the small stuff, put it in position and
invite your biggest friends over and offer each one of them a six-pack of
beer or whatever if they can bend it by doing chinups and bouncing on it,
with their hands as close together as possible. My guess is that you will
be buying. Oh, make them wear a football or motorcycle helmet in case the
bar comes down on top of them :-).
-----
Regards,
Carl Ijames
"Maddog" wrote in message
news:2f424$55a01a6a$43de0cc0$30...@news.flashnewsgroups.com...
usually load hung from 2 points at 1-2 feet apart rather than just at
center (worst case)". That implies that you believe that the loads spring
into existence in position, not that they are lifted off the floor. It's
the jerking and bouncing during that lift that make this a live load and
require at least a factor of 3-5 safety factor. Even if you don't see it,
it is happening, and what if something sticks or someone walks by and gives
it a swing just for fun? Yes, spreading the attachment points on the pipe
help, but I wouldn't lift more than maybe 200 lbs with 1.5" sched 40 pipe so
I think you should go on up to 2" galvanized steel pipe, and maybe even
schedule 80 instead of 40. Spend an extra $5 and have a LOT more peace of
mind later. If you do insist on the small stuff, put it in position and
invite your biggest friends over and offer each one of them a six-pack of
beer or whatever if they can bend it by doing chinups and bouncing on it,
with their hands as close together as possible. My guess is that you will
be buying. Oh, make them wear a football or motorcycle helmet in case the
bar comes down on top of them :-).
-----
Regards,
Carl Ijames
"Maddog" wrote in message
walter_...@post.com
Jul 10, 2015, 4:20:44 PM7/10/15
to
Carl Ijames wrote:
> ...
> ...
> Oh, make them wear a football or motorcycle helmet in case the
> bar comes down on top of them :-).
Why can't they wear those black iron skillets?
> bar comes down on top of them :-).
Jim Wilkins
Jul 10, 2015, 5:23:03 PM7/10/15
to
"Carl Ijames" <carl.i...@XXverizon.net> wrote in message
news:mnp6t...@news3.newsguy.com...
He could block the ends that high off the floor, place adhesive tape
sticky side up under the center, and see if the test load picks up the
tape.
Joe Gwinn
Jul 10, 2015, 5:44:15 PM7/10/15
to
In article <2f424$55a01a6a$43de0cc0$30...@news.flashnewsgroups.com>,
A better solution is to get a length of structural I-beam from a local
steelyard. I-beams are intended for what you are doing, while
pressure pipe is not. Structural steel is not expensive.
There are structural steel tables and online calculators to give
deflection and yield levels. You need a safety factor of at least five
to one: design for 500*5= 2500 pounds at yield.
By the way, is it a problem if the load migrates to the center by
itself when lifted? If the beam isn't stiff enough, that is exactly
what will happen.
Also, as the beam bends, it tends to pull out of the end sockets. How
will this tendency be prevented, such that the beam cannot pull free
and drop load and beam?
Joe Gwinn
Maddog <0f8503901d844703ee...@example.com> wrote:
> replying to Jim Wilkins , Maddog wrote:
> > muratlanne wrote:
> >
> > "Carl Ijames" <carl.i...@XXverizon.net> wrote in message
> > news:mnnhp...@news7.newsguy.com...
> > I recently investigated and ran the numbers for 2" pipe column
> > strength, and found warnings that water pipe steel isn't rated for
> > structures and its yield point could be as low as 25,000 PSI.
>
>
> Thanks gentlemen! All great & valuable responses. Carl's assumptions are
> right. This Schd. 40 Pipe will be horizontal with each end sitting in a
> slotted wood block. There is no axial load, and nothing inside the pipe.
> It will only be used overhead in my garage as an occasional lifting point
> or sling support. Stationary loads, with no bouncing or swinging, and
> usually load hung from 2 points at 1-2 feet apart rather than just at
> center (worst case). I know the pipe is not designed for or intended for
> such use, but it is simple & inexpensive.
> Sounds like it will work for my intended loads of 500 lbs. or less.
> My only question still remaining is if the galvanized pipe would be a bit
> stronger than the black iron pipe? Just a few bucks more. I'll mesasure to
> see if wall thickness is any different.
You are asking for a disaster.
> replying to Jim Wilkins , Maddog wrote:
> > muratlanne wrote:
> >
> > "Carl Ijames" <carl.i...@XXverizon.net> wrote in message
> > news:mnnhp...@news7.newsguy.com...
> > I recently investigated and ran the numbers for 2" pipe column
> > strength, and found warnings that water pipe steel isn't rated for
> > structures and its yield point could be as low as 25,000 PSI.
>
>
> Thanks gentlemen! All great & valuable responses. Carl's assumptions are
> right. This Schd. 40 Pipe will be horizontal with each end sitting in a
> slotted wood block. There is no axial load, and nothing inside the pipe.
> It will only be used overhead in my garage as an occasional lifting point
> or sling support. Stationary loads, with no bouncing or swinging, and
> usually load hung from 2 points at 1-2 feet apart rather than just at
> center (worst case). I know the pipe is not designed for or intended for
> such use, but it is simple & inexpensive.
> Sounds like it will work for my intended loads of 500 lbs. or less.
> My only question still remaining is if the galvanized pipe would be a bit
> stronger than the black iron pipe? Just a few bucks more. I'll mesasure to
> see if wall thickness is any different.
A better solution is to get a length of structural I-beam from a local
steelyard. I-beams are intended for what you are doing, while
pressure pipe is not. Structural steel is not expensive.
There are structural steel tables and online calculators to give
deflection and yield levels. You need a safety factor of at least five
to one: design for 500*5= 2500 pounds at yield.
By the way, is it a problem if the load migrates to the center by
itself when lifted? If the beam isn't stiff enough, that is exactly
what will happen.
Also, as the beam bends, it tends to pull out of the end sockets. How
will this tendency be prevented, such that the beam cannot pull free
and drop load and beam?
Joe Gwinn
dca...@krl.org
Jul 10, 2015, 9:09:22 PM7/10/15
to
On Friday, July 10, 2015 at 5:44:15 PM UTC-4, Joe Gwinn wrote:
> A better solution is to get a length of structural I-beam from a local
> steelyard. I-beams are intended for what you are doing, while
> pressure pipe is not. Structural steel is not expensive.
I have not run the numbers, but you might also look at getting some 2 by 2 by 3/16 or 1/4 wall or 2 by 3 tubing. The increase in size to 2 or 3 inches in depth will be a lot stronger than 1 1/2 inch pipe.
> A better solution is to get a length of structural I-beam from a local
> steelyard. I-beams are intended for what you are doing, while
> pressure pipe is not. Structural steel is not expensive.
Dan
Cydrome Leader
Jul 13, 2015, 12:33:49 PM7/13/15
to
dca...@krl.org <dca...@krl.org> wrote:
> On Friday, July 10, 2015 at 5:44:15 PM UTC-4, Joe Gwinn wrote:
>
>
>> A better solution is to get a length of structural I-beam from a local
>> steelyard. I-beams are intended for what you are doing, while
>> pressure pipe is not. Structural steel is not expensive.
>
> I have not run the numbers, but you might also look at getting some 2 by 2 by 3/16 or 1/4 wall or 2 by 3 tubing. The increase in size to 2 or 3 inches in depth will be a lot stronger than 1 1/2 inch pipe.
Why not just double up and use two piece of pipe if that's all that's
> On Friday, July 10, 2015 at 5:44:15 PM UTC-4, Joe Gwinn wrote:
>
>
>> A better solution is to get a length of structural I-beam from a local
>> steelyard. I-beams are intended for what you are doing, while
>> pressure pipe is not. Structural steel is not expensive.
>
> I have not run the numbers, but you might also look at getting some 2 by 2 by 3/16 or 1/4 wall or 2 by 3 tubing. The increase in size to 2 or 3 inches in depth will be a lot stronger than 1 1/2 inch pipe.
available?
A 10 foot piece of pipe at a box store costs less than ANY of the precut
pieces they have anyways.
mjacob...@gmail.com
Sep 21, 2016, 1:31:46 AM9/21/16
to
On Thursday, July 9, 2015 at 7:18:04 PM UTC-7, Maddog wrote:
stewcarm...@gmail.com
Jul 6, 2017, 11:08:56 PM7/6/17
to
Hello, i read the whole thread.... But what if i was trying to build a crane over a job site and had a similar idea using the same materials? How could i improve it?... Big factors to keep in mind are portability (easy setup and take down), least weight vs. Highest strength of steel piping, safety, and lowest possible cost.
Jim Wilkins
Jul 7, 2017, 8:00:23 AM7/7/17
to
<stewcarm...@gmail.com> wrote in message
news:5a16d72e-3b13-48a6...@googlegroups.com...
===============================================
This column calculator takes pipe 2" and up:
https://courses.cit.cornell.edu/arch264/calculators/example7.3/index.html
"Pinned at both ends" means the load is applied directly in line with
the pipe, without sideways force that tends to bow it. That restricts
your design considerably, all the commercial hoists I've studied apply
a cantilevered load to the columns which requires more complex
calculations.
http://www.strucalc.com/cantilever-column/
W sections are better than pipe for the bending loads on horizontal
beams.
http://www.engineeringtoolbox.com/american-wide-flange-steel-beams-d_1319.html
It's possible to build a portable gantry crane with a simple geometry
that uses only pinned- or ball-end columns but I can't prove the
safety of my design and won't describe it. I test everything for
deflection with a measured proof load, and sometimes find unexpected
weakness or bad material.
-xyz
news:5a16d72e-3b13-48a6...@googlegroups.com...
This column calculator takes pipe 2" and up:
https://courses.cit.cornell.edu/arch264/calculators/example7.3/index.html
"Pinned at both ends" means the load is applied directly in line with
the pipe, without sideways force that tends to bow it. That restricts
your design considerably, all the commercial hoists I've studied apply
a cantilevered load to the columns which requires more complex
calculations.
http://www.strucalc.com/cantilever-column/
W sections are better than pipe for the bending loads on horizontal
beams.
http://www.engineeringtoolbox.com/american-wide-flange-steel-beams-d_1319.html
It's possible to build a portable gantry crane with a simple geometry
that uses only pinned- or ball-end columns but I can't prove the
safety of my design and won't describe it. I test everything for
deflection with a measured proof load, and sometimes find unexpected
weakness or bad material.
-xyz
Jim Wilkins
Jul 7, 2017, 5:39:39 PM7/7/17
to
"Jim Wilkins" <murat...@gmail.com> wrote in message
news:ojnstb$bqm$1...@dont-email.me...
news:ojnstb$bqm$1...@dont-email.me...
> <stewcarm...@gmail.com> wrote in message
> news:5a16d72e-3b13-48a6...@googlegroups.com...
> Hello, i read the whole thread.... But what if i was trying to build
> a crane over a job site and had a similar idea using the same
> materials? How could i improve it?... Big factors to keep in mind
> are portability (easy setup and take down), least weight vs. Highest
> strength of steel piping, safety, and lowest possible cost.
> ===============================================
>
http://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1102&context=braesp
> news:5a16d72e-3b13-48a6...@googlegroups.com...
> Hello, i read the whole thread.... But what if i was trying to build
> a crane over a job site and had a similar idea using the same
> materials? How could i improve it?... Big factors to keep in mind
> are portability (easy setup and take down), least weight vs. Highest
> strength of steel piping, safety, and lowest possible cost.
> ===============================================
>
Ray Hayes
Feb 24, 2018, 11:18:12 AM2/24/18
to
replying to mjacobsen925, Ray Hayes wrote:
Your reply is foolish. This appears to be a valid question about using a pipe
section to support a hoist - an overhead lifting design that requires
calculation. 1.5" black iron pipe is the support beam suggested for available
electric garage hoists.
For any who care, stress = M*c/I = M/s.
Bending moment = M = WL/2, s = 0.326 in^3 for 1.5" sch 40 pipe. Assume yield
strength=30,000 psi. L=60".
stress = M/s = W*L/(2*s). If Safety Factor = 2.0 (low for a lifting
operation - F.S> should be 6 for overhead lifting):
Yield/F.S = 30000 psi/2.0 = 15000 psi = W*60/(2*0.326); W = 163 lbs. Yield
Strength (30,000 psi) is the load where the pipe will bend without springing
back to straight.
Original request was for a 1" deflection at the center. This is way overloaded
- typical beam limit might be L/360 = 0.167". But just for yucks:
max deflection = y = W*L^3/(48*E*I); E=29e6, I = 0.310 in^4 (1.5" sch 40
pipe).
y/W = 60^3/(48*29e6&*0.310) = 0.0005, or W/y = 2000, or W = 2000*y. So to get
a 1.0" deflection on a 60" pipe (if it did not yield) would be W=2000 * 1.0 =
2000 lbs. *BUT the stress with that 2000# load would be M/s = W*L/(2*s) =
2000*60/(2*.326) = 184,000 psi - 6 times the yield strength (meaning the pipe
would bend to failure). *For reference, limiting deflection to L/360 would
allow a load of:
W = 2000*y = 2000*(60/360) = 333 lbs. This corresponds to a F.S. = about 1.0.
Take away - pipe is not as strong as it looks. Don't stand under that hoist,
be careful it does not snag on something that lets it go to its full cable
tension unless the support beam can handle that weight.
--
for full context, visit https://www.polytechforum.com/metalworking/weight-bearing-strength-of-5-ft-of-black-iron-pipe-639655-.htm
Your reply is foolish. This appears to be a valid question about using a pipe
section to support a hoist - an overhead lifting design that requires
calculation. 1.5" black iron pipe is the support beam suggested for available
electric garage hoists.
For any who care, stress = M*c/I = M/s.
Bending moment = M = WL/2, s = 0.326 in^3 for 1.5" sch 40 pipe. Assume yield
strength=30,000 psi. L=60".
stress = M/s = W*L/(2*s). If Safety Factor = 2.0 (low for a lifting
operation - F.S> should be 6 for overhead lifting):
Yield/F.S = 30000 psi/2.0 = 15000 psi = W*60/(2*0.326); W = 163 lbs. Yield
Strength (30,000 psi) is the load where the pipe will bend without springing
back to straight.
Original request was for a 1" deflection at the center. This is way overloaded
- typical beam limit might be L/360 = 0.167". But just for yucks:
max deflection = y = W*L^3/(48*E*I); E=29e6, I = 0.310 in^4 (1.5" sch 40
pipe).
y/W = 60^3/(48*29e6&*0.310) = 0.0005, or W/y = 2000, or W = 2000*y. So to get
a 1.0" deflection on a 60" pipe (if it did not yield) would be W=2000 * 1.0 =
2000 lbs. *BUT the stress with that 2000# load would be M/s = W*L/(2*s) =
2000*60/(2*.326) = 184,000 psi - 6 times the yield strength (meaning the pipe
would bend to failure). *For reference, limiting deflection to L/360 would
allow a load of:
W = 2000*y = 2000*(60/360) = 333 lbs. This corresponds to a F.S. = about 1.0.
Take away - pipe is not as strong as it looks. Don't stand under that hoist,
be careful it does not snag on something that lets it go to its full cable
tension unless the support beam can handle that weight.
--
for full context, visit https://www.polytechforum.com/metalworking/weight-bearing-strength-of-5-ft-of-black-iron-pipe-639655-.htm
Jim Wilkins
Feb 24, 2018, 1:05:51 PM2/24/18
to
"Ray Hayes" <0f8503901d844703ee...@example.com> wrote
in message news:_egkC.1748501$w26.6...@fx47.am4...
I bolted the HF 1300# electric hoist directly to a gantry trolley I
welded from 1/4" thick angle iron, with wheels, axles and bearings
copied from the HF 2000# trolley hoist, except that their axles are
pressed into the frame while mine pass through it with nuts on the
outside.
The hoist starts up with a substantial jerk that may apply double or
more the steady load to the support.
I've seen 25000 psi suggested as the yield for imported water pipe
made from random scrap steel.
https://www.ebay.com/i/232626917798?chn=ps
-jsw
in message news:_egkC.1748501$w26.6...@fx47.am4...
welded from 1/4" thick angle iron, with wheels, axles and bearings
copied from the HF 2000# trolley hoist, except that their axles are
pressed into the frame while mine pass through it with nuts on the
outside.
The hoist starts up with a substantial jerk that may apply double or
more the steady load to the support.
I've seen 25000 psi suggested as the yield for imported water pipe
made from random scrap steel.
https://www.ebay.com/i/232626917798?chn=ps
-jsw
rmhay...@gmail.com
Feb 25, 2018, 7:57:03 AM2/25/18
to
Jim Wilkins
Feb 25, 2018, 9:17:18 AM2/25/18
to
<rmhay...@gmail.com> wrote in message
news:0be9561c-40f9-4472...@googlegroups.com...
===
I use this to quickly determine what available material is or isn't
practical before refining the design:
http://www.amesweb.info/StructuralBeamDeflection/SimpleBeamConcentratedLoadAtAnyPoint.aspx
news:0be9561c-40f9-4472...@googlegroups.com...
I use this to quickly determine what available material is or isn't
practical before refining the design:
http://www.amesweb.info/StructuralBeamDeflection/SimpleBeamConcentratedLoadAtAnyPoint.aspx
Message has been deleted
rmhay...@gmail.com
Mar 1, 2018, 9:13:03 AM3/1/18
to
Goncalves
Aug 2, 2019, 9:18:04 AM8/2/19
to
replying to mjacobsen925, Goncalves wrote:
Really mjacobsen925, a forum is where one asks questions not where one gets
censored.
Really mjacobsen925, a forum is where one asks questions not where one gets
censored.
Linda Iverson
Apr 3, 2021, 10:38:28 PM4/3/21
to
Clare Snyder
Apr 4, 2021, 12:47:09 AM4/4/21
to
sag
Robert Nichols
Apr 4, 2021, 10:50:29 AM4/4/21
to
--
Bob Nichols AT comcast.net I am "RNichols42"
Clare Snyder
Apr 4, 2021, 5:52:08 PM4/4/21
to
drapery
Robert Nichols
Apr 4, 2021, 10:20:36 PM4/4/21
to
That's quite some curtain rod!!
Clare Snyder
Apr 4, 2021, 11:57:47 PM4/4/21
to
On Sun, 4 Apr 2021 21:19:14 -0500, Robert Nichols
But it will support itself and some load over a 12 ft span. (about 1
1/2 times?? as much as sched 40.
Just did as bit of investigating and 1 1/4 inch sched 80 should be
adequate for a pretty heavy curtain - and weigh about 40 lb? - about
10 lb per meter) will sipport about 30 lb evenly didtributed with
about an inch of deflection.
Sched 40 will only handle around 20 lb with almost 1 1/2 inches of
deflection with a wight of ropughly 30 lb.
1/2 times?? as much as sched 40.
Just did as bit of investigating and 1 1/4 inch sched 80 should be
adequate for a pretty heavy curtain - and weigh about 40 lb? - about
10 lb per meter) will sipport about 30 lb evenly didtributed with
about an inch of deflection.
Sched 40 will only handle around 20 lb with almost 1 1/2 inches of
deflection with a wight of ropughly 30 lb.
Bob Engelhardt
Apr 5, 2021, 9:37:53 AM4/5/21
to
On 4/3/2021 10:38 PM, Linda Iverson wrote:
> What if I just want to use black steel pipe as a curtain rod to hang heavy velvet drapes spanning a window greater than 12 feet long without the need for a center support? I’ll anchor ends using flanges (nipples and elbows) screwed into solid wooden header above window. Seems like it should be more than strong enough for such a girly thing.
>
"Strong enough"? It depends - it will be strong enough to not fall
> What if I just want to use black steel pipe as a curtain rod to hang heavy velvet drapes spanning a window greater than 12 feet long without the need for a center support? I’ll anchor ends using flanges (nipples and elbows) screwed into solid wooden header above window. Seems like it should be more than strong enough for such a girly thing.
>
down, but it will sag. How much sag depends upon the weight of the
"heavy velvet drapes" & the diameter of the pipe. If you specify the
weight & the maximum sag acceptable, someone here can tell you the pipe
size to use. However, heavy drapes and a 12' span mean that the sag
will probably be unacceptable for anything but a really big pipe.
whit3rd
Apr 5, 2021, 1:19:24 PM4/5/21
to
On Saturday, April 3, 2021 at 7:38:28 PM UTC-7, Linda Iverson wrote:
> What if I just want to use black steel pipe as a curtain rod to hang heavy velvet drapes spanning a window greater than 12 feet long without the need for a center support? I’ll anchor ends using flanges (nipples and elbows) screwed into solid wooden header above window. Seems like it should be more than strong enough for such a girly thing.
Strong enough, perhaps, but for sag-resistance you want diameter, but not wall thickness (like
> What if I just want to use black steel pipe as a curtain rod to hang heavy velvet drapes spanning a window greater than 12 feet long without the need for a center support? I’ll anchor ends using flanges (nipples and elbows) screwed into solid wooden header above window. Seems like it should be more than strong enough for such a girly thing.
a water/air pipe intended for machine-threading the ends). Fence rail items
<https://www.lowes.com/pd/Vinyl-Coated-Steel-Chain-Link-Fence-Top-Rail/999978242>
have less pounds per foot of metal, but are cold-worked steel and should perform
acceptably; they join end-to-end (and with a bit of Liquid Nails applied, the joints will be rigid
enough for most purposes).
Designs of curtain rails of formed sheet metal will allow a 12 foot span, with
a brace at 6 feet, that doesn't interfere with the drape support elements (sliding plastic
in a steel channel). A central brace in these designs is usually not visible with the curtain closed.
Eli the Bearded
Apr 5, 2021, 1:34:14 PM4/5/21
to
In rec.crafts.metalworking, Bob Engelhardt <BobEng...@comcast.net> wrote:
> On 4/3/2021 10:38 PM, Linda Iverson wrote:
>> What if I just want to use black steel pipe as a curtain rod to hang heavy
>> velvet drapes spanning a window greater than 12 feet long without the need
>> for a center support?
> On 4/3/2021 10:38 PM, Linda Iverson wrote:
>> What if I just want to use black steel pipe as a curtain rod to hang heavy
>> velvet drapes spanning a window greater than 12 feet long without the need
>> for a center support?
> If you specify the weight & the maximum sag acceptable, someone here
> can tell you the pipe size to use. However, heavy drapes and a 12'
> span mean that the sag will probably be unacceptable for anything but
> a really big pipe.
Or hide the sag with a valance box.
> can tell you the pipe size to use. However, heavy drapes and a 12'
> span mean that the sag will probably be unacceptable for anything but
> a really big pipe.
Elijah
------
as old fashioned as heavy velvet drapes
Richard Smith
Apr 6, 2021, 8:06:05 AM4/6/21
to
load it can take and the deflection at that load to great accuracy.
If you set-up the load on the finished article, you'd find the
deflection matched to within a millimetre or something like that.
The end supports cannot be anything like rigid enough against rotation
to benefit the load capacity and stiffness against deflection.
You've got a "simple supported beam" ("double-supported beam").
A fair and reasonable conservative assumption would be to put the
entire weight of the curtain in the middle of the "curtain rail" when
doing the Euler-Bernoulli calculation for what tube to specify.
So that truly is the "simply supported centrally-loaded beam" case.
I do a lot of these calculations.
eg.
http://www.weldsmith.co.uk/tech/struct/210314_ebbeam_drillplat/19_drillplat_calcs.html
Rich Smith
Jim Wilkins
Apr 6, 2021, 8:47:56 AM4/6/21
to
"Richard Smith" wrote in message news:ly5z0z6...@richards-air-2.home...
Clare Snyder <cl...@snyder.on.ca> writes:
.....................
That's Euler-Bernoulli beam - very clear and exact. You can have the
load it can take and the deflection at that load to great accuracy.
If you set-up the load on the finished article, you'd find the
deflection matched to within a millimetre or something like that.
The end supports cannot be anything like rigid enough against rotation
to benefit the load capacity and stiffness against deflection.
You've got a "simple supported beam" ("double-supported beam").
A fair and reasonable conservative assumption would be to put the
entire weight of the curtain in the middle of the "curtain rail" when
doing the Euler-Bernoulli calculation for what tube to specify.
So that truly is the "simply supported centrally-loaded beam" case.
I do a lot of these calculations.
eg.
http://www.weldsmith.co.uk/tech/struct/210314_ebbeam_drillplat/19_drillplat_calcs.html
Rich Smith
--------------------------
https://www.archtoolbox.com/materials-systems/plumbing/standard-pipe-dimensions.html
https://amesweb.info/section/section-properties-calculator.aspx
https://amesweb.info/Beam/beam-deflection-calculator.aspx
Water pipe attached to a vertical wall with elbows, close nipples and floor
flanges is Simply Supported because the threads can rotate within the
flange.
Pipe and fence tubing longer than 10' is hard to find, and transport. A
center support makes this problem MUCH simpler.
Clare Snyder <cl...@snyder.on.ca> writes:
.....................
That's Euler-Bernoulli beam - very clear and exact. You can have the
load it can take and the deflection at that load to great accuracy.
If you set-up the load on the finished article, you'd find the
deflection matched to within a millimetre or something like that.
The end supports cannot be anything like rigid enough against rotation
to benefit the load capacity and stiffness against deflection.
You've got a "simple supported beam" ("double-supported beam").
A fair and reasonable conservative assumption would be to put the
entire weight of the curtain in the middle of the "curtain rail" when
doing the Euler-Bernoulli calculation for what tube to specify.
So that truly is the "simply supported centrally-loaded beam" case.
I do a lot of these calculations.
eg.
http://www.weldsmith.co.uk/tech/struct/210314_ebbeam_drillplat/19_drillplat_calcs.html
Rich Smith
https://www.archtoolbox.com/materials-systems/plumbing/standard-pipe-dimensions.html
https://amesweb.info/section/section-properties-calculator.aspx
https://amesweb.info/Beam/beam-deflection-calculator.aspx
Water pipe attached to a vertical wall with elbows, close nipples and floor
flanges is Simply Supported because the threads can rotate within the
flange.
Pipe and fence tubing longer than 10' is hard to find, and transport. A
center support makes this problem MUCH simpler.
Clare Snyder
Apr 6, 2021, 1:08:54 PM4/6/21
to
On Tue, 06 Apr 2021 13:06:00 +0100, Richard Smith <nu...@void.com>
wrote:
Interesting liittle project - O like your reasoning and explanation -
particularly your "tap stick"
I've run into a lot of your "welders" who would make the thing so
heavy it could hardly support itself!!! (or they would fasten it to
the rig instead of the barge and it would be so heavy it would tip the
rig before it would bend - - -
wrote:
particularly your "tap stick"
I've run into a lot of your "welders" who would make the thing so
heavy it could hardly support itself!!! (or they would fasten it to
the rig instead of the barge and it would be so heavy it would tip the
rig before it would bend - - -
Robert Nichols
Apr 6, 2021, 11:35:16 PM4/6/21
to
have a decorative design, and still be very rigid.
Richard Smith
Apr 7, 2021, 4:58:06 AM4/7/21
to
Clare Snyder <cl...@snyder.on.ca> writes:
> On Tue, 06 Apr 2021 13:06:00 +0100, Richard Smith <nu...@void.com>
>>>>>>> .............
> On Tue, 06 Apr 2021 13:06:00 +0100, Richard Smith <nu...@void.com>
>>
>>I do a lot of these calculations.
>>eg.
>>http://www.weldsmith.co.uk/tech/struct/210314_ebbeam_drillplat/19_drillplat_calcs.html
>>
>>
>>Rich Smith
> Interesting liittle project - O like your reasoning and explanation -
> particularly your "tap stick"
> I've run into a lot of your "welders" who would make the thing so
> heavy it could hardly support itself!!! (or they would fasten it to
> the rig instead of the barge and it would be so heavy it would tip the
> rig before it would bend - - -
background of experience.
I wanted "inherent safety" - that there would be "clue sticks" along
any way the equipment could be abused.
Richard Smith
Apr 7, 2021, 5:14:43 AM4/7/21
to
Robert Nichols <SEE_SI...@localhost.localdomain.invalid> writes:
>>>>>>>> ...........
[digression from OP's purpose]
If the strength had been any less / if it hadn't felt right when
assembled, I'd have probably done that.
Form a "tent-shape" triangular truss part, rising diagonally from the
deck to the top of the first "stanchion" then sloping down diagonally
to about the middle of the deck?
Ultimately - the strength was enough, while the secondary steelwork
with the "clue-sticks" incorporated drew-out the safety margin
desired.
>>>>>>>> ...........
[digression from OP's purpose]
assembled, I'd have probably done that.
Form a "tent-shape" triangular truss part, rising diagonally from the
deck to the top of the first "stanchion" then sloping down diagonally
to about the middle of the deck?
Ultimately - the strength was enough, while the secondary steelwork
with the "clue-sticks" incorporated drew-out the safety margin
desired.
Robert Nichols
Apr 7, 2021, 9:20:35 AM4/7/21
to
with diagonal members welded in. I made something like that out of square
tubing a while back, and it turned out about 10X stronger than it needed
to be.
Jim Wilkins
Apr 7, 2021, 7:32:16 PM4/7/21
to
"Richard Smith" wrote in message news:lyo8eq3...@richards-air-2.home...
If the strength had been any less / if it hadn't felt right when
assembled, I'd have probably done that.
Form a "tent-shape" triangular truss part, rising diagonally from the
deck to the top of the first "stanchion" then sloping down diagonally
to about the middle of the deck?
Ultimately - the strength was enough, while the secondary steelwork
with the "clue-sticks" incorporated drew-out the safety margin
desired.
------------------
The most effective place to add support to a cantilever structure is about
1/4 of the way in from the end, as long as its beams are equally strong in
tension and compression.
If the strength had been any less / if it hadn't felt right when
assembled, I'd have probably done that.
Form a "tent-shape" triangular truss part, rising diagonally from the
deck to the top of the first "stanchion" then sloping down diagonally
to about the middle of the deck?
Ultimately - the strength was enough, while the secondary steelwork
with the "clue-sticks" incorporated drew-out the safety margin
desired.
The most effective place to add support to a cantilever structure is about
1/4 of the way in from the end, as long as its beams are equally strong in
tension and compression.
Richard Smith
Apr 8, 2021, 4:29:40 AM4/8/21
to
Robert Nichols <SEE_SI...@localhost.localdomain.invalid> writes:
>>>>>.....
>> desired.
>
> I was thinking more along the lines of a double rail, about 3 inches apart,
> with diagonal members welded in. I made something like that out of square
> tubing a while back, and it turned out about 10X stronger than it needed
> to be.
>
> --
> Bob Nichols AT comcast.net I am "RNichols42"
Good point.
As a cantilever beam, highest moment is where structural meets the barge.
So add a "doubler" in that region would "do the trick".
>>>>>.....
>> desired.
>
> I was thinking more along the lines of a double rail, about 3 inches apart,
> with diagonal members welded in. I made something like that out of square
> tubing a while back, and it turned out about 10X stronger than it needed
> to be.
>
> --
> Bob Nichols AT comcast.net I am "RNichols42"
As a cantilever beam, highest moment is where structural meets the barge.
So add a "doubler" in that region would "do the trick".
Richard Smith
Apr 8, 2021, 4:30:59 AM4/8/21
to
"Jim Wilkins" <murat...@gmail.com> writes:
>
> ------------------
>
> The most effective place to add support to a cantilever structure is
> about 1/4 of the way in from the end, as long as its beams are equally
> strong in tension and compression.
Not quite getting that. Anywhere you can put up a sketch?
>
> ------------------
>
> The most effective place to add support to a cantilever structure is
> about 1/4 of the way in from the end, as long as its beams are equally
> strong in tension and compression.
Richard Smith
Apr 8, 2021, 5:25:28 AM4/8/21
to
Answer for the Original Poster...
I took the case from this - you will see what I've taken as your
situation fromteh numbers I settle on.
https://www.polytechforum.com/metalworking/weight-bearing-strength-of-5-ft-of-black-iron-pipe-639655-.htm
I note Ray Hayes' explanation, where he looks to have used the same
methodology
Ray Hayes
posted on February 23, 2018, 2:31 pm
# replying to mjacobsen925, Ray Hayes wrote: Your reply is
# foolish. This appears to be a valid question about using a pipe
# section to support a hoist - an overhead lifting design that
# requires calculation. 1.5" black iron pipe is the support beam
# suggested for available electric garage hoists.
# For any who care, stress = M*c/I = M/s. Bending moment = M = WL/2, s
# = 0.326 in^3 for 1.5" sch 40 pipe. Assume yield strength0,000
# psi. L`". stress = M/s = W*L/(2*s). If Safety Factor = 2.0 (low for
# a lifting operation - F.S> should be 6 for overhead lifting):
# Yield/F.S = 30000 psi/2.0 = 15000 psi = W*60/(2*0.326); W = 163
# lbs. Yield Strength (30,000 psi) is the load where the pipe will
# bend without springing back to straight. Original request was for a
# 1" deflection at the center. This is way overloaded - typical beam
# limit might be L/360 = 0.167". But just for yucks: max deflection =
# y = W*L^3/(48*E*I); E)e6, I = 0.310 in^4 (1.5" sch 40 pipe). y/W =
# 60^3/(48*29e6&*0.310) = 0.0005, or W/y = 2000, or W = 2000*y. So to
# get a 1.0" deflection on a 60" pipe (if it did not yield) would be W
# 00 * 1.0 = 2000 lbs. *BUT the stress with that 2000# load would be
# M/s = W*L/(2*s) 2000*60/(2*.326) = 184,000 psi - 6 times the yield
# strength (meaning the pipe would bend to failure). *For reference,
# limiting deflection to L/360 would allow a load of: W = 2000*y =
# 2000*(60/360) = 333 lbs. This corresponds to a F.S. = about 1.0.
Dimensions for 1~1/2" Sched 40 tube
Nom OD ID w-thk
1.5 1.900 1.61 0.15
(* 1.9 25.4) ;; 48.26
(* 0.15 25.4) ;; 3.8099999999999996
If I'm not mistaken, that's the dimensions of scaffold tube as we know
it here in the UK.
I can tell you - a 6m length
(- (/ 6e3 25.4) (* 12 19)) ;; 8.220472440944889
19ft 8in length !!!
of scaffold tube supported on its ends will just take my weight in the
middle - about 87kg
(/ 87 0.4536) ;; 191.7989417989418
192lb
I'm going to use a yield strength of 235MPa
There is every likelihood the yield is higher than that.
So the value I'll calculate is the minimum load-bearing possible.
The Young's modulus at 2.1e11Pa is almost independent of steel
strength, so the deflection prediction is invariant of steel grade.
Using my functions
;; moment cap
(* 235e6
(beam-sect-mod-z-d
;; args I, d
(ma2nd-annulus-dia-wthk-cx 48.3e-3 3.8e-3) ; 1.3245821667837055e-07 ; m^4
48.3e-3) ; 5.484812284818656e-06 ; m^3
) ; 1288.9308869323843 ; N.m
So moment capacity is 1289 Newton-metres
(* 60 25.4 1e-3) ;; 1.524 ;; m length
(/
(simple-support-dblbeam-loadcap
;; M_cap, l
1288.9308869323843
1.524) ;; 3383.0207006099326 ;; N (Newtons)
9.81) ; 344.8543017951001 ; kg-f
(/ 345 0.4536) ;; 760.5820105820105
So your curtain rail will bear 760lb at the middle
That's more than enough for a kid swinging on it.
Deflection - which is your question...
(dblsupport-centralload-beam-deflect
;; F(central), l, E, I
(* 344.8543017951001 9.8) ;; 3379.5721575919815 ;; N
1.524 ;; m length of curtain rail
2e11 ;; Elastic modulus of steel (Pa)
(ma2nd-annulus-dia-wthk-cx 48.3e-3 3.8e-3) ;; 1.3245821667837055e-07 ;; m^4 ma-2nd
) ;; 0.00940733235828569 ;; m of deflection at onset of deformation
(/
(* 0.00940733235828569 1e3) ;; 9.40733235828569 ;; mm deflection
25.4) ;; 0.370367415680539
(* 0.370367415680539 8) ;; 2.962939325444312 ;; about 3/8th-inch
Even at maximum loading of 345kg / 760lb the middle of the curtain
rail will be only 9.4mm / 3/8th"
I hope that's the answer to the question.
I took the case from this - you will see what I've taken as your
situation fromteh numbers I settle on.
https://www.polytechforum.com/metalworking/weight-bearing-strength-of-5-ft-of-black-iron-pipe-639655-.htm
I note Ray Hayes' explanation, where he looks to have used the same
methodology
Ray Hayes
posted on February 23, 2018, 2:31 pm
# replying to mjacobsen925, Ray Hayes wrote: Your reply is
# foolish. This appears to be a valid question about using a pipe
# section to support a hoist - an overhead lifting design that
# requires calculation. 1.5" black iron pipe is the support beam
# suggested for available electric garage hoists.
# For any who care, stress = M*c/I = M/s. Bending moment = M = WL/2, s
# = 0.326 in^3 for 1.5" sch 40 pipe. Assume yield strength0,000
# psi. L`". stress = M/s = W*L/(2*s). If Safety Factor = 2.0 (low for
# a lifting operation - F.S> should be 6 for overhead lifting):
# Yield/F.S = 30000 psi/2.0 = 15000 psi = W*60/(2*0.326); W = 163
# lbs. Yield Strength (30,000 psi) is the load where the pipe will
# bend without springing back to straight. Original request was for a
# 1" deflection at the center. This is way overloaded - typical beam
# limit might be L/360 = 0.167". But just for yucks: max deflection =
# y = W*L^3/(48*E*I); E)e6, I = 0.310 in^4 (1.5" sch 40 pipe). y/W =
# 60^3/(48*29e6&*0.310) = 0.0005, or W/y = 2000, or W = 2000*y. So to
# get a 1.0" deflection on a 60" pipe (if it did not yield) would be W
# 00 * 1.0 = 2000 lbs. *BUT the stress with that 2000# load would be
# M/s = W*L/(2*s) 2000*60/(2*.326) = 184,000 psi - 6 times the yield
# strength (meaning the pipe would bend to failure). *For reference,
# limiting deflection to L/360 would allow a load of: W = 2000*y =
# 2000*(60/360) = 333 lbs. This corresponds to a F.S. = about 1.0.
Dimensions for 1~1/2" Sched 40 tube
Nom OD ID w-thk
1.5 1.900 1.61 0.15
(* 1.9 25.4) ;; 48.26
(* 0.15 25.4) ;; 3.8099999999999996
If I'm not mistaken, that's the dimensions of scaffold tube as we know
it here in the UK.
I can tell you - a 6m length
(- (/ 6e3 25.4) (* 12 19)) ;; 8.220472440944889
19ft 8in length !!!
of scaffold tube supported on its ends will just take my weight in the
middle - about 87kg
(/ 87 0.4536) ;; 191.7989417989418
192lb
I'm going to use a yield strength of 235MPa
There is every likelihood the yield is higher than that.
So the value I'll calculate is the minimum load-bearing possible.
The Young's modulus at 2.1e11Pa is almost independent of steel
strength, so the deflection prediction is invariant of steel grade.
Using my functions
;; moment cap
(* 235e6
(beam-sect-mod-z-d
;; args I, d
(ma2nd-annulus-dia-wthk-cx 48.3e-3 3.8e-3) ; 1.3245821667837055e-07 ; m^4
48.3e-3) ; 5.484812284818656e-06 ; m^3
) ; 1288.9308869323843 ; N.m
So moment capacity is 1289 Newton-metres
(* 60 25.4 1e-3) ;; 1.524 ;; m length
(/
(simple-support-dblbeam-loadcap
;; M_cap, l
1288.9308869323843
1.524) ;; 3383.0207006099326 ;; N (Newtons)
9.81) ; 344.8543017951001 ; kg-f
(/ 345 0.4536) ;; 760.5820105820105
So your curtain rail will bear 760lb at the middle
That's more than enough for a kid swinging on it.
Deflection - which is your question...
(dblsupport-centralload-beam-deflect
;; F(central), l, E, I
(* 344.8543017951001 9.8) ;; 3379.5721575919815 ;; N
1.524 ;; m length of curtain rail
2e11 ;; Elastic modulus of steel (Pa)
(ma2nd-annulus-dia-wthk-cx 48.3e-3 3.8e-3) ;; 1.3245821667837055e-07 ;; m^4 ma-2nd
) ;; 0.00940733235828569 ;; m of deflection at onset of deformation
(/
(* 0.00940733235828569 1e3) ;; 9.40733235828569 ;; mm deflection
25.4) ;; 0.370367415680539
(* 0.370367415680539 8) ;; 2.962939325444312 ;; about 3/8th-inch
Even at maximum loading of 345kg / 760lb the middle of the curtain
rail will be only 9.4mm / 3/8th"
I hope that's the answer to the question.
Bob La Londe
Apr 8, 2021, 10:48:27 AM4/8/21
to
to the job then.
--
This email has been checked for viruses by AVG.
https://www.avg.com
Bob La Londe
Apr 8, 2021, 6:47:17 PM4/8/21
to
Richard Smith
Apr 10, 2021, 8:32:04 AM4/10/21
to
curtain-rail...
Maximum central load before permanent bend =
143.7kg-f
=
317lb-f
At that load, at centre
54 mm deflection
=
2~1/8th inch deflection
If two children were climbing the curtains at the middle, you'd have
higher concerns than whether the bottom of the curtains is still
exactly level with the floor for the duration of their adventure...
Rich Smith
0 new messages