Discussion:
Any advice on making a cattle grid?
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n***@aolbin.com
2022-01-09 14:18:37 UTC
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A job that will soon reach the top of the pile is making a cattle grid,
primarily to stop the dog from wandering down the drive and on to the
road. It needs to be 4-5m wide and about 2m front-back. I'll probably
cast a concrete trough to put it in, with one side open to an adjacent
dingle so water and hedgehogs can escape, and so it can be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports and
use scaffold pipes for the top surface. The I-sections would sit on
concrete piers to get sufficient depth. I'd weld the pipework in four
sections so it's removable.

Does this sound sensible?

How can I calculate what load a scaffold pipe can take without
permanently deforming?

The scaffold pipes will be galvanised so I'll be grinding the joint
areas clean before welding, and then spraying with a zinc-rich paint.
How can I protect the I-sections from rust?

Any other thoughts, ideas, considerations?
williamwright
2022-01-09 14:45:40 UTC
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I would check to see that your dog *can’t* cross a cattle grid first. Some
dogs are smarter/more agile than others.
Tim
Round bars deter dogs better than flat topped ones. However, one of my
dogs learnt how to get across by using the flat edge of the grid for two
legs. And I have heard tell of dogs rolling across...

Bill
williamwright
2022-01-09 15:15:51 UTC
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Why are you confident your Dog won't simply jump across?
I guess he's tied its back legs together

Bill
The Natural Philosopher
2022-01-09 15:29:40 UTC
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Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle grid,
primarily to stop the dog from wandering down the drive
I vividly remember a story about how a circus trainer got a tiger to
walk on bottle tops. he started with a plank, and gradually cut away the
bits in between

At one time we had a dog shocker that hit the dogs near the boundary.
The big dog caught a whiff of bitch on heat and off he went.

And hour later he trotted back broke into a run and there was a massive
yelp and he shot a couple of feet in the air as the shock collar got
him, but he still made it back in.

Moral. I don't think you have a cats (dogs?) chance in hell of keeping a
dog in with anything less than an unclimbable barrier.
--
“Some people like to travel by train because it combines the slowness of
a car with the cramped public exposure of 
an airplane.”

Dennis Miller
newshound
2022-01-09 15:47:51 UTC
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Post by The Natural Philosopher
Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle
grid, primarily to stop the dog from wandering down the drive
I vividly remember a story about how a circus trainer got a tiger to
walk on bottle tops. he started with a plank, and gradually cut away the
bits in between
At one time we had a dog shocker that hit the dogs near the boundary.
The big dog caught a whiff of bitch on heat and off he went.
And hour later he trotted back broke into a run and there was a massive
yelp and he shot a couple of feet in the air as the shock collar got
him, but he still made it back in.
Moral. I don't think you have a cats (dogs?) chance in hell of keeping a
dog in with anything less than an unclimbable barrier.
It does very much depend on the dog, though. I recall having kittens
when a small collie cleared a local cattle grid on to the road. OTOT a
cattle grid with only two round bars would keep my wife's elderly Bichon
Frises in.
The Natural Philosopher
2022-01-09 15:30:41 UTC
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Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle grid,
primarily to stop the dog from wandering down the drive and on to the
road. It needs to be 4-5m wide and about 2m front-back. I'll probably
cast a concrete trough to put it in, with one side open to an adjacent
dingle so water and hedgehogs can escape, and so it can be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports and
use scaffold pipes for the top surface. The I-sections would sit on
concrete piers to get sufficient depth. I'd weld the pipework in four
sections so it's removable.
Does this sound sensible?
How can I calculate what load a scaffold pipe can take without
permanently deforming?
The scaffold pipes will be galvanised so I'll be grinding the joint
areas clean before welding, and then spraying with a zinc-rich paint.
How can I protect the I-sections from rust?
Any other thoughts, ideas, considerations?
I would check to see that your dog *can’t* cross a cattle grid first. Some
dogs are smarter/more agile than others.
Tim
Exactly - 2 m isn't far for a dog to leap, and what is more likely is he
will try and break a leg
--
"Socialist governments traditionally do make a financial mess. They
always run out of other people's money. It's quite a characteristic of them"

Margaret Thatcher
alan_m
2022-01-09 21:33:24 UTC
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Post by The Natural Philosopher
Exactly - 2 m isn't far for a dog to leap, and what is more likely is he
will try and break a leg
+1
A broken leg is a real risk
--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk
The Natural Philosopher
2022-01-09 15:31:19 UTC
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Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle
grid, primarily to stop the dog from wandering down the drive and on
to the road. It needs to be 4-5m wide and about 2m front-back. I'll
probably cast a concrete trough to put it in, with one side open to an
adjacent dingle so water and hedgehogs can escape, and so it can be
hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports
and use scaffold pipes for the top surface. The I-sections would sit
on concrete piers to get sufficient depth. I'd weld the pipework in
four sections so it's removable.
Does this sound sensible?
How can I calculate what load a scaffold pipe can take without
permanently deforming?
The scaffold pipes will be galvanised so I'll be grinding the joint
areas clean before welding, and then spraying with a zinc-rich paint.
How can I protect the I-sections from rust?
Any other thoughts, ideas, considerations?
Why are you confident your Dog won't simply jump across? Geriatric?
You used to be able to use a radio controlled collar but I think they
relied on an electric shock and may have been banned.
yup. now banned. Stupid, they mostly actually worked.
--
“Politics is the art of looking for trouble, finding it everywhere,
diagnosing it incorrectly and applying the wrong remedies.”
― Groucho Marx
nightjar
2022-01-09 16:23:24 UTC
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Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle grid,
primarily to stop the dog from wandering down the drive and on to the
road. It needs to be 4-5m wide and about 2m front-back. I'll probably
cast a concrete trough to put it in, with one side open to an adjacent
dingle so water and hedgehogs can escape, and so it can be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports and
use scaffold pipes for the top surface. The I-sections would sit on
concrete piers to get sufficient depth. I'd weld the pipework in four
sections so it's removable.
Does this sound sensible?
How can I calculate what load a scaffold pipe can take without
permanently deforming?
The scaffold pipes will be galvanised so I'll be grinding the joint
areas clean before welding, and then spraying with a zinc-rich paint.
How can I protect the I-sections from rust?
Any other thoughts, ideas, considerations?
Guidance available on the internet:

https://www.farmranchstore.com/information/2019/2/20/everything-you-need-to-know-about-cattle-grids

There also seem to be a lot of second hand ones for sale on ebay.
--
Colin Bignell
n***@aolbin.com
2022-01-09 21:34:58 UTC
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Post by nightjar
Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle
grid, primarily to stop the dog from wandering down the drive and on
to the road. It needs to be 4-5m wide and about 2m front-back. I'll
probably cast a concrete trough to put it in, with one side open to an
adjacent dingle so water and hedgehogs can escape, and so it can be
hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports
and use scaffold pipes for the top surface. The I-sections would sit
on concrete piers to get sufficient depth. I'd weld the pipework in
four sections so it's removable.
Does this sound sensible?
How can I calculate what load a scaffold pipe can take without
permanently deforming?
The scaffold pipes will be galvanised so I'll be grinding the joint
areas clean before welding, and then spraying with a zinc-rich paint.
How can I protect the I-sections from rust?
Any other thoughts, ideas, considerations?
https://www.farmranchstore.com/information/2019/2/20/everything-you-need-to-know-about-cattle-grids
There also seem to be a lot of second hand ones for sale on ebay.
Not in my neck of the woods, but I keep checking.
Max Demian
2022-01-09 17:31:02 UTC
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Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle grid,
primarily to stop the dog from wandering down the drive and on to the
road. It needs to be 4-5m wide and about 2m front-back. I'll probably
cast a concrete trough to put it in, with one side open to an adjacent
dingle so water and hedgehogs can escape, and so it can be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports and
use scaffold pipes for the top surface. The I-sections would sit on
concrete piers to get sufficient depth. I'd weld the pipework in four
sections so it's removable.
I've often wondered, how do cows and sheep learn not to attempt to cross
cattle grids without getting their hooves stuck?
--
Max Demian
Owain Lastname
2022-01-09 18:33:03 UTC
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Post by Max Demian
I've often wondered, how do cows and sheep learn not to attempt to cross
cattle grids without getting their hooves stuck?
Is it a visual thing?

There's a youtube video of police horses objecting to a rainbow-painted zebra crossing.

Owain
Tim Lamb
2022-01-09 20:14:51 UTC
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Post by Owain Lastname
Post by Max Demian
I've often wondered, how do cows and sheep learn not to attempt to cross
cattle grids without getting their hooves stuck?
Is it a visual thing?
There's a youtube video of police horses objecting to a rainbow-painted zebra crossing.
Horses will spook at all sorts of things. An A4 sheet of paper turning
over in a wind will do it.

I had some farmland (now part of Heartwood forest!) where the field edge
bridleway skirts some drainage ponds. Regularly there would be a set of
hoof prints through the crop where a horse had baulked at passing the
ponds.
--
Tim Lamb
newshound
2022-01-09 20:39:33 UTC
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Post by Tim Lamb
Post by Owain Lastname
Post by Max Demian
I've often wondered, how do cows and sheep learn not to attempt to cross
cattle grids without getting their hooves stuck?
Is it a visual thing?
There's a youtube video of police horses objecting to a
rainbow-painted zebra crossing.
Horses will spook at all sorts of things. An A4 sheet of paper turning
over in a wind will do it.
In the summer, a brown leaf would do it for one of mine. She once backed
right off a "contour" path on to a 40 degree wooded downhill slope
because of one. To her eternal credit, instead of dumping me she then
turned uphill, dug in her back legs, and clambered out while keeping me
nicely balanced.
Chris Green
2022-01-09 20:43:43 UTC
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Post by Tim Lamb
Post by Owain Lastname
Post by Max Demian
I've often wondered, how do cows and sheep learn not to attempt to cross
cattle grids without getting their hooves stuck?
Is it a visual thing?
There's a youtube video of police horses objecting to a rainbow-painted zebra crossing.
Horses will spook at all sorts of things. An A4 sheet of paper turning
over in a wind will do it.
Exactly! In my (quite long, 60 years or so) of riding horses they
will never cease to surprise one at what frightens them, and what
doesn't frighten them.

My current horse is almost totally traffic proof, buses, large
loriies, noisy cars, no problem. However he still walks carefully
round a manhole cover a few hundred yards from home.

It's mostly things they can't quite 'understand' that throws them, and
also things that disappear or hide.

A previous horse of ours found marching soldiers were a very strange
animal but would quite happily walk calmly through woods where the
same soldiers were firing blanks (I hope they were) at each other. I
never quite fathomed out why we were allowed in the woods while
exercises were going on.

People who retreated behind trees and hedges to avoid 'frightening the
horses' were a real pain, much better just to keep in sight and look
like normal human beings.
--
Chris Green
·
nightjar
2022-01-09 20:16:58 UTC
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Post by Owain Lastname
Post by Max Demian
I've often wondered, how do cows and sheep learn not to attempt to cross
cattle grids without getting their hooves stuck?
Is it a visual thing?
Quite possibly. This link, which I posted earlier refers to virtual
cattle grids, painted on the ground. However, it doesn't say whether
cattle need to have encountered real grids before or not:

https://www.farmranchstore.com/information/2019/2/20/everything-you-need-to-know-about-cattle-grids
Post by Owain Lastname
There's a youtube video of police horses objecting to a rainbow-painted zebra crossing.
Owain
--
Colin Bignell
Rod Speed
2022-01-09 18:54:26 UTC
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Post by Max Demian
Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle grid,
primarily to stop the dog from wandering down the drive and on to the
road. It needs to be 4-5m wide and about 2m front-back. I'll probably
cast a concrete trough to put it in, with one side open to an adjacent
dingle so water and hedgehogs can escape, and so it can be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports and
use scaffold pipes for the top surface. The I-sections would sit on
concrete piers to get sufficient depth. I'd weld the pipework in four
sections so it's removable.
I've often wondered, how do cows and sheep learn not to attempt to cross
cattle grids without getting their hooves stuck?
They don’t learn, they don’t even try to cross it.

Herbivores aren't exactly what you might call rocket scientist material.
misterroy
2022-01-09 19:14:24 UTC
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Post by Rod Speed
Post by Max Demian
Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle grid,
primarily to stop the dog from wandering down the drive and on to the
road. It needs to be 4-5m wide and about 2m front-back. I'll probably
cast a concrete trough to put it in, with one side open to an adjacent
dingle so water and hedgehogs can escape, and so it can be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports and
use scaffold pipes for the top surface. The I-sections would sit on
concrete piers to get sufficient depth. I'd weld the pipework in four
sections so it's removable.
I've often wondered, how do cows and sheep learn not to attempt to cross
cattle grids without getting their hooves stuck?
They don’t learn, they don’t even try to cross it.
Herbivores aren't exactly what you might call rocket scientist material.
The dog will be able to cross any cattle grid.
A friends red setter climbed a 14 foot brick wall to get to a bitch on heat.
Rod Speed
2022-01-09 19:38:18 UTC
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Post by misterroy
Post by Rod Speed
Post by Max Demian
Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle grid,
primarily to stop the dog from wandering down the drive and on to the
road. It needs to be 4-5m wide and about 2m front-back. I'll probably
cast a concrete trough to put it in, with one side open to an adjacent
dingle so water and hedgehogs can escape, and so it can be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports and
use scaffold pipes for the top surface. The I-sections would sit on
concrete piers to get sufficient depth. I'd weld the pipework in four
sections so it's removable.
I've often wondered, how do cows and sheep learn not to attempt to cross
cattle grids without getting their hooves stuck?
They don’t learn, they don’t even try to cross it.
Herbivores aren't exactly what you might call rocket scientist material.
The dog will be able to cross any cattle grid.
Plenty can't with the best grids.
Post by misterroy
A friends red setter climbed a 14 foot brick wall to get to a bitch on heat.
You don’t know that the OP's is a dog rather than a bitch.
Peeler
2022-01-09 20:26:16 UTC
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On Mon, 10 Jan 2022 06:38:18 +1100, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

<FLUSH the abnormal trolling senile cretin's latest trollshit unread>
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"Who or What is Rod Speed?

Rod Speed is an entirely modern phenomenon. Essentially, Rod Speed
is an insecure and worthless individual who has discovered he can
enhance his own self-esteem in his own eyes by playing "the big, hard
man" on the InterNet."
https://www.pcreview.co.uk/threads/rod-speed-faq.2973853/
Peeler
2022-01-09 19:25:56 UTC
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On Mon, 10 Jan 2022 05:54:26 +1100, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

<FLUSH the abnormal trolling senile cretin's latest trollshit unread>
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Norman Wells addressing trolling senile Rodent:
"Ah, the voice of scum speaks."
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Caecilius
2022-01-10 16:25:36 UTC
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Post by Max Demian
Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle grid,
primarily to stop the dog from wandering down the drive and on to the
road. It needs to be 4-5m wide and about 2m front-back. I'll probably
cast a concrete trough to put it in, with one side open to an adjacent
dingle so water and hedgehogs can escape, and so it can be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports and
use scaffold pipes for the top surface. The I-sections would sit on
concrete piers to get sufficient depth. I'd weld the pipework in four
sections so it's removable.
I've often wondered, how do cows and sheep learn not to attempt to cross
cattle grids without getting their hooves stuck?
Cattle are scared of trips and falls because they can easily injure
their legs, and a broken leg is probably going to be fatal.

Just the visual appearance of a cattle grid is enough to keep most
cows away, and it's sometimes possible to keep cows out temporarily by
painting lines on the roadway. But invariably there's one smart or
brave cow that will learn that they can cross, and once they do the
others will follow.
newshound
2022-01-09 20:34:40 UTC
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Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle grid,
primarily to stop the dog from wandering down the drive and on to the
road. It needs to be 4-5m wide and about 2m front-back. I'll probably
cast a concrete trough to put it in, with one side open to an adjacent
dingle so water and hedgehogs can escape, and so it can be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports and
use scaffold pipes for the top surface. The I-sections would sit on
concrete piers to get sufficient depth. I'd weld the pipework in four
sections so it's removable.
Does this sound sensible?
How can I calculate what load a scaffold pipe can take without
permanently deforming?
The scaffold pipes will be galvanised so I'll be grinding the joint
areas clean before welding, and then spraying with a zinc-rich paint.
How can I protect the I-sections from rust?
Any other thoughts, ideas, considerations?
I would check to see that your dog *can’t* cross a cattle grid first.
Some
dogs are smarter/more agile than others.
Not just dogs. There was a report (on Look North, I think) many years
ago of sheep repeatedly escaping from a field. It turned out that they'd
learned to tuck their legs in and roll over the cattle grids.
Slightly different, I know, but a colleague who was brought up on a farm
(where his older brother used to make him test electric fencing by
touching it) tells me some of their cattle were smart enough to barge
another cow into an electric fence to knock it down.
n***@aolbin.com
2022-01-09 21:35:41 UTC
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Post by newshound
Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle grid,
primarily to stop the dog from wandering down the drive and on to the
road. It needs to be 4-5m wide and about 2m front-back. I'll probably
cast a concrete trough to put it in, with one side open to an adjacent
dingle so water and hedgehogs can escape, and so it can be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports and
use scaffold pipes for the top surface. The I-sections would sit on
concrete piers to get sufficient depth. I'd weld the pipework in four
sections so it's removable.
Does this sound sensible?
How can I calculate what load a scaffold pipe can take without
permanently deforming?
The scaffold pipes will be galvanised so I'll be grinding the joint
areas clean before welding, and then spraying with a zinc-rich paint.
How can I protect the I-sections from rust?
Any other thoughts, ideas, considerations?
I would check to see that your dog *can’t* cross a cattle grid first.
Some
dogs are smarter/more agile than others.
Not just dogs. There was a report (on Look North, I think) many years
ago of sheep repeatedly escaping from a field. It turned out that
they'd learned to tuck their legs in and roll over the cattle grids.
Slightly different, I know, but a colleague who was brought up on a farm
(where his older brother used to make him test electric fencing by
touching it) tells me some of their cattle were smart enough to barge
another cow into an electric fence to knock it down.
At least he didn't get him to pee on it !!!
John Walliker
2022-01-10 14:22:49 UTC
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Post by n***@aolbin.com
Post by newshound
Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle grid,
primarily to stop the dog from wandering down the drive and on to the
road. It needs to be 4-5m wide and about 2m front-back. I'll probably
cast a concrete trough to put it in, with one side open to an adjacent
dingle so water and hedgehogs can escape, and so it can be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports and
use scaffold pipes for the top surface. The I-sections would sit on
concrete piers to get sufficient depth. I'd weld the pipework in four
sections so it's removable.
Does this sound sensible?
How can I calculate what load a scaffold pipe can take without
permanently deforming?
The scaffold pipes will be galvanised so I'll be grinding the joint
areas clean before welding, and then spraying with a zinc-rich paint.
How can I protect the I-sections from rust?
Any other thoughts, ideas, considerations?
I would check to see that your dog *can’t* cross a cattle grid first.
Some
dogs are smarter/more agile than others.
Not just dogs. There was a report (on Look North, I think) many years
ago of sheep repeatedly escaping from a field. It turned out that
they'd learned to tuck their legs in and roll over the cattle grids.
Slightly different, I know, but a colleague who was brought up on a farm
(where his older brother used to make him test electric fencing by
touching it) tells me some of their cattle were smart enough to barge
another cow into an electric fence to knock it down.
At least he didn't get him to pee on it !!!
I have also seen a dog crossing a cattle grid by walking along the side support.

John
n***@aolbin.com
2022-01-09 21:29:20 UTC
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Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle grid,
primarily to stop the dog from wandering down the drive and on to the
road. It needs to be 4-5m wide and about 2m front-back. I'll probably
cast a concrete trough to put it in, with one side open to an adjacent
dingle so water and hedgehogs can escape, and so it can be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports and
use scaffold pipes for the top surface. The I-sections would sit on
concrete piers to get sufficient depth. I'd weld the pipework in four
sections so it's removable.
Does this sound sensible?
How can I calculate what load a scaffold pipe can take without
permanently deforming?
The scaffold pipes will be galvanised so I'll be grinding the joint
areas clean before welding, and then spraying with a zinc-rich paint.
How can I protect the I-sections from rust?
Any other thoughts, ideas, considerations?
I would check to see that your dog *can’t* cross a cattle grid first. Some
dogs are smarter/more agile than others.
Tim
He's a Welsh Collie (so is supposed to be smart) but a 2m grid of round
pipes should be enough of a deterrent when chasing
rabbits/birds/squirrels ... when I first typed this I missed the "t"
from rabbits, but talk of chasing Rabbis is probably banned in these
Woke times ;-)
alan_m
2022-01-09 21:31:30 UTC
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I would check to see that your dog *can’t* cross a cattle grid first. Some
dogs are smarter/more agile than others.
Tim
My friend's dog easily cleared a real rural cattle grid when approaching
it at full running speed. He had a bit of trouble returning across it
when trying to walk back.
--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk
n***@aolbin.com
2022-01-09 21:32:47 UTC
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Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle
grid, primarily to stop the dog from wandering down the drive and on
to the road. It needs to be 4-5m wide and about 2m front-back. I'll
probably cast a concrete trough to put it in, with one side open to an
adjacent dingle so water and hedgehogs can escape, and so it can be
hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports
and use scaffold pipes for the top surface. The I-sections would sit
on concrete piers to get sufficient depth. I'd weld the pipework in
four sections so it's removable.
Does this sound sensible?
How can I calculate what load a scaffold pipe can take without
permanently deforming?
The scaffold pipes will be galvanised so I'll be grinding the joint
areas clean before welding, and then spraying with a zinc-rich paint.
How can I protect the I-sections from rust?
Any other thoughts, ideas, considerations?
Think carefully about the side "fences", need to be over grid with no
lip the dog can walk along. I used gates which could be closed but need
to plan for the posts when you are building it.
I had one made up locally and dip galvanised, I think they used some old
3-4" steam pipes. I think 4 I-beams is a bit OTT for domestic use.
You can buy them ready made but no idea what the costs are these days.
As I had an old tractor with front loader lifting in one piece wasnt an
issue.
The sides will be tied-in to existing fences, and I'll cut-away a bank
to make a footpath with pedestrian gate.
Buying a grid would be a bit pricey (and not in the spirit of DIY).
Robert
2022-01-10 21:27:46 UTC
Reply
Permalink
Post by n***@aolbin.com
Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle
grid, primarily to stop the dog from wandering down the drive and on
to the road. It needs to be 4-5m wide and about 2m front-back. I'll
probably cast a concrete trough to put it in, with one side open to
an adjacent dingle so water and hedgehogs can escape, and so it can
be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports
and use scaffold pipes for the top surface. The I-sections would sit
on concrete piers to get sufficient depth. I'd weld the pipework in
four sections so it's removable.
Does this sound sensible?
How can I calculate what load a scaffold pipe can take without
permanently deforming?
The scaffold pipes will be galvanised so I'll be grinding the joint
areas clean before welding, and then spraying with a zinc-rich paint.
How can I protect the I-sections from rust?
Any other thoughts, ideas, considerations?
Think carefully about the side "fences", need to be over grid with no
lip the dog can walk along. I used gates which could be closed but
need to plan for the posts when you are building it.
I had one made up locally and dip galvanised, I think they used some
old 3-4" steam pipes. I think 4 I-beams is a bit OTT for domestic use.
You can buy them ready made but no idea what the costs are these days.
As I had an old tractor with front loader lifting in one piece wasnt
an issue.
The sides will be tied-in to existing fences, and I'll cut-away a bank
to make a footpath with pedestrian gate.
Buying a grid would be a bit pricey (and not in the spirit of DIY).
A visit to a scrap yard or scrap metal dealer might produce some nice
tubing. Thinking about it the smaller diameter tubing would be more
difficult for a dog to cross than the larger sizes I mentioned.
n***@aolbin.com
2022-01-10 22:23:25 UTC
Reply
Permalink
Post by Robert
Post by n***@aolbin.com
Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle
grid, primarily to stop the dog from wandering down the drive and on
to the road. It needs to be 4-5m wide and about 2m front-back. I'll
probably cast a concrete trough to put it in, with one side open to
an adjacent dingle so water and hedgehogs can escape, and so it can
be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports
and use scaffold pipes for the top surface. The I-sections would sit
on concrete piers to get sufficient depth. I'd weld the pipework in
four sections so it's removable.
Does this sound sensible?
How can I calculate what load a scaffold pipe can take without
permanently deforming?
The scaffold pipes will be galvanised so I'll be grinding the joint
areas clean before welding, and then spraying with a zinc-rich
paint. How can I protect the I-sections from rust?
Any other thoughts, ideas, considerations?
Think carefully about the side "fences", need to be over grid with no
lip the dog can walk along. I used gates which could be closed but
need to plan for the posts when you are building it.
I had one made up locally and dip galvanised, I think they used some
old 3-4" steam pipes. I think 4 I-beams is a bit OTT for domestic use.
You can buy them ready made but no idea what the costs are these days.
As I had an old tractor with front loader lifting in one piece wasnt
an issue.
The sides will be tied-in to existing fences, and I'll cut-away a bank
to make a footpath with pedestrian gate.
Buying a grid would be a bit pricey (and not in the spirit of DIY).
A visit to a scrap yard or scrap metal dealer might produce some nice
tubing. Thinking about it the smaller diameter tubing would be more
difficult for a dog to cross than the larger sizes I mentioned.
Yes, it would be good to use scaffold tube but I don't know how to do
the sums to see what load it would cope with. Where do mechanical
engineers hide when you want one ;-)
Chris Green
2022-01-11 09:35:59 UTC
Reply
Permalink
Post by n***@aolbin.com
Post by Robert
Post by n***@aolbin.com
The sides will be tied-in to existing fences, and I'll cut-away a bank
to make a footpath with pedestrian gate.
Buying a grid would be a bit pricey (and not in the spirit of DIY).
A visit to a scrap yard or scrap metal dealer might produce some nice
tubing. Thinking about it the smaller diameter tubing would be more
difficult for a dog to cross than the larger sizes I mentioned.
Yes, it would be good to use scaffold tube but I don't know how to do
the sums to see what load it would cope with. Where do mechanical
engineers hide when you want one ;-)
Any half-decent mechanical engineer will ask what you want to drive
over the grid, ask the width of the 'hole' and then say "yes, that
will be fine" (or not fine, of course). :-)
--
Chris Green
·
newshound
2022-01-11 15:31:56 UTC
Reply
Permalink
Post by Chris Green
Post by n***@aolbin.com
Post by Robert
Post by n***@aolbin.com
The sides will be tied-in to existing fences, and I'll cut-away a bank
to make a footpath with pedestrian gate.
Buying a grid would be a bit pricey (and not in the spirit of DIY).
A visit to a scrap yard or scrap metal dealer might produce some nice
tubing. Thinking about it the smaller diameter tubing would be more
difficult for a dog to cross than the larger sizes I mentioned.
Yes, it would be good to use scaffold tube but I don't know how to do
the sums to see what load it would cope with. Where do mechanical
engineers hide when you want one ;-)
Any half-decent mechanical engineer will ask what you want to drive
over the grid, ask the width of the 'hole' and then say "yes, that
will be fine" (or not fine, of course). :-)
Here is the first "tube calculator" thrown up by google

https://www.roguefab.com/tube-calculator

Never tried it but superficially it looks OK.
Robert
2022-01-11 21:26:29 UTC
Reply
Permalink
Post by n***@aolbin.com
Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle
grid, primarily to stop the dog from wandering down the drive and on
to the road. It needs to be 4-5m wide and about 2m front-back. I'll
probably cast a concrete trough to put it in, with one side open to
an adjacent dingle so water and hedgehogs can escape, and so it can
be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports
and use scaffold pipes for the top surface. The I-sections would sit
on concrete piers to get sufficient depth. I'd weld the pipework in
four sections so it's removable.
Does this sound sensible?
How can I calculate what load a scaffold pipe can take without
permanently deforming?
The scaffold pipes will be galvanised so I'll be grinding the joint
areas clean before welding, and then spraying with a zinc-rich paint.
How can I protect the I-sections from rust?
Any other thoughts, ideas, considerations?
Think carefully about the side "fences", need to be over grid with no
lip the dog can walk along. I used gates which could be closed but
need to plan for the posts when you are building it.
I had one made up locally and dip galvanised, I think they used some
old 3-4" steam pipes. I think 4 I-beams is a bit OTT for domestic use.
You can buy them ready made but no idea what the costs are these days.
As I had an old tractor with front loader lifting in one piece wasnt
an issue.
The sides will be tied-in to existing fences, and I'll cut-away a bank
to make a footpath with pedestrian gate.
Buying a grid would be a bit pricey (and not in the spirit of DIY).
A quick Google gives you some idea of the standard designs for
residential cattle grids .
i.e.
https://www.cattlegrids.com/wp-content/pdf-files/Data-Sheet-All-Steel-26t.pdf
Obviously big savings to be made if you can diy with cheap materials or
find a 2nd hand one going cheap.
newshound
2022-01-11 21:55:52 UTC
Reply
Permalink
Post by Robert
A quick Google gives you some idea of the standard designs for
residential cattle grids .
i.e.
https://www.cattlegrids.com/wp-content/pdf-files/Data-Sheet-All-Steel-26t.pdf
Obviously big savings to be made if you can diy with cheap materials or
find a 2nd hand one going cheap.
Useful link. CHS or circular hollow section is just a posh way of saying
"tube".
n***@aolbin.com
2022-01-09 21:34:17 UTC
Reply
Permalink
Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle
grid, primarily to stop the dog from wandering down the drive and on
to the road. It needs to be 4-5m wide and about 2m front-back. I'll
probably cast a concrete trough to put it in, with one side open to an
adjacent dingle so water and hedgehogs can escape, and so it can be
hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports
and use scaffold pipes for the top surface. The I-sections would sit
on concrete piers to get sufficient depth. I'd weld the pipework in
four sections so it's removable.
Does this sound sensible?
How can I calculate what load a scaffold pipe can take without
permanently deforming?
The scaffold pipes will be galvanised so I'll be grinding the joint
areas clean before welding, and then spraying with a zinc-rich paint.
How can I protect the I-sections from rust?
Any other thoughts, ideas, considerations?
Why are you confident your Dog won't simply jump across? Geriatric?
He's still young (I wish I was) but don't you think a 2m depth should be
enough?
You used to be able to use a radio controlled collar but I think they
relied on an electric shock and may have been banned.
I investigated these but there are a number of practical and operational
difficulties
Peter Johnson
2022-01-10 15:07:41 UTC
Reply
Permalink
Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle grid,
primarily to stop the dog from wandering down the drive and on to the
road. It needs to be 4-5m wide and about 2m front-back. I'll probably
cast a concrete trough to put it in, with one side open to an adjacent
dingle so water and hedgehogs can escape, and so it can be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports and
use scaffold pipes for the top surface. The I-sections would sit on
concrete piers to get sufficient depth. I'd weld the pipework in four
sections so it's removable.
Any other thoughts, ideas, considerations?
If you have a heritage railway not far away ask them if they have any
suitable scrap rail that can be cut to length. 45lb or so per yard
would do so a narrow gauge line is more likely to have suitable
material but a standard gauge line could have lighter rail lying
around.
Brian Gaff (Sofa)
2022-01-10 16:05:16 UTC
Reply
Permalink
I seem to recall that this kind of thing could fall foul of health and
safety regulations these days. If the dog broke its ankle you might not be
too pleased. Are there cattle around?

If there is a gate here, I guess it could have a safe electric fence on the
inside?
Cattle grid seems a lot of work.
Brian
--
This newsgroup posting comes to you directly from...
The Sofa of Brian Gaff...
***@blueyonder.co.uk
Blind user, so no pictures please
Note this Signature is meaningless.!
Post by n***@aolbin.com
A job that will soon reach the top of the pile is making a cattle grid,
primarily to stop the dog from wandering down the drive and on to the road.
It needs to be 4-5m wide and about 2m front-back. I'll probably cast a
concrete trough to put it in, with one side open to an adjacent dingle so
water and hedgehogs can escape, and so it can be hosed-out.
I'm only just starting to think about how to do it, but the current
thought is to get four 2m lengths of I-section for the main supports and
use scaffold pipes for the top surface. The I-sections would sit on
concrete piers to get sufficient depth. I'd weld the pipework in four
sections so it's removable.
Does this sound sensible?
How can I calculate what load a scaffold pipe can take without permanently
deforming?
The scaffold pipes will be galvanised so I'll be grinding the joint areas
clean before welding, and then spraying with a zinc-rich paint. How can I
protect the I-sections from rust?
Any other thoughts, ideas, considerations?
alan_m
2022-01-10 19:15:10 UTC
Reply
Permalink
Post by n***@aolbin.com
How can I calculate what load a scaffold pipe can take without
permanently deforming?
You could always strengthen it by welding vertical sections of pipe from
the middle of the horizontal pole to the base of the pit.
--
mailto : news {at} admac {dot} myzen {dot} co {dot} uk
newshound
2022-01-10 19:31:37 UTC
Reply
Permalink
Post by n***@aolbin.com
How can I calculate what load a scaffold pipe can take without
permanently deforming?
It's not a particularly difficult calculation. I don't have the
dimensions or UTS of scaffold pole to hand, but someone here probably
has. Presumably you want to drive over it? Goods vehicles?
n***@aolbin.com
2022-01-10 22:27:53 UTC
Reply
Permalink
Post by newshound
Post by n***@aolbin.com
How can I calculate what load a scaffold pipe can take without
permanently deforming?
It's not a particularly difficult calculation. I don't have the
dimensions or UTS of scaffold pole to hand, but someone here probably
has. Presumably you want to drive over it? Goods vehicles?
Yes, it would be on the access drive, a short way from the gates.
Regular car and van usage with occasional lorry use for deliveries and
removals.
newshound
2022-01-11 15:53:44 UTC
Reply
Permalink
Post by n***@aolbin.com
Post by newshound
Post by n***@aolbin.com
How can I calculate what load a scaffold pipe can take without
permanently deforming?
It's not a particularly difficult calculation. I don't have the
dimensions or UTS of scaffold pole to hand, but someone here probably
has. Presumably you want to drive over it? Goods vehicles?
Yes, it would be on the access drive, a short way from the gates.
Regular car and van usage with occasional lorry use for deliveries and
removals.
So what sized lorry? If no more than a 7.5 tonner then your axle load is
presumably no more than 4 tonnes. In the worst case that might just
about be applied to a single tube.

I see others have done some sums. The issue isn't so much deflection (as
in flooring calcs) as whether it will bend pipes permanently. That's a
bit trickier if the pipes are welded to I beams, but you'd get a good
enough (and conservative) answer by assuming a simply supported beam and
applying 4 tonnes in the middle. I know the lorry wheels are separated,
but you could also have some dynamic loading.

You will need to know the tensile yield strength of scaffold tubes as
well as the dimensions. This from a forum so not checked against source.
This is 235 MPa.

"BS 12811 cites at 4.2.1.2 for steel tubes a minimum nominal yield
strength of 235N/mm^2 for a nominal OD of 48.3mm and minimum minimum
wall thickness of 3.2mm"

Suggest you try the calculator that I linked earlier.
The Natural Philosopher
2022-01-11 18:34:56 UTC
Reply
Permalink
The issue isn't so much deflection (as in flooring calcs) as whether it
will bend pipes permanently.
I've bent a scaffold pipe permanently by hand. wedge one end of a 10 ft
section and walk with the other end,

It really is the worst grade shit imaginable
--
There is nothing a fleet of dispatchable nuclear power plants cannot do
that cannot be done worse and more expensively and with higher carbon
emissions and more adverse environmental impact by adding intermittent
renewable energy.
newshound
2022-01-11 20:49:12 UTC
Reply
Permalink
Post by The Natural Philosopher
The issue isn't so much deflection (as in flooring calcs) as whether
it will bend pipes permanently.
I've bent a scaffold pipe permanently by hand. wedge one end of a 10 ft
section and walk with the other end,
It really is the worst grade shit imaginable
The tensile strength is low. On the other hand, the strain to failure is
large, which is what you want really.
The Natural Philosopher
2022-01-12 11:13:09 UTC
Reply
Permalink
Post by newshound
Post by The Natural Philosopher
The issue isn't so much deflection (as in flooring calcs) as whether
it will bend pipes permanently.
I've bent a scaffold pipe permanently by hand. wedge one end of a 10
ft section and walk with the other end,
It really is the worst grade shit imaginable
The tensile strength is low. On the other hand, the strain to failure is
large, which is what you want really.
If you dont mind your poles reaching the pit bottom after a twenty
tonner has gone over.

High strain to failure with low elasticity means plastic deformation,
You want springiness...
--
New Socialism consists essentially in being seen to have your heart in
the right place whilst your head is in the clouds and your hand is in
someone else's pocket.
newshound
2022-01-12 12:42:04 UTC
Reply
Permalink
Post by The Natural Philosopher
Post by newshound
Post by The Natural Philosopher
The issue isn't so much deflection (as in flooring calcs) as whether
it will bend pipes permanently.
I've bent a scaffold pipe permanently by hand. wedge one end of a 10
ft section and walk with the other end,
It really is the worst grade shit imaginable
The tensile strength is low. On the other hand, the strain to failure
is large, which is what you want really.
If you dont mind your poles reaching the pit bottom after a twenty
tonner has gone over.
High strain to failure with low elasticity means plastic deformation,
You want springiness...
Don't be obtuse, you were complaining that scaffold poles were weak, and
I was pointing out that you want scaffold tubes to be ductile. So yes,
they are not an ideal choice for a cattle grid, you would be better to
make these from a "structural steel" with a higher yield stress. But
OTOH they are more readily available and affordable. If you go to a
steel supplier looking for something with a yield strength of say 350MPa
it's going to be more expensive than random steel scaffold tube (and of
course there is a second hand trade in that too).
The Natural Philosopher
2022-01-12 13:00:52 UTC
Reply
Permalink
Post by newshound
Post by The Natural Philosopher
Post by newshound
Post by The Natural Philosopher
The issue isn't so much deflection (as in flooring calcs) as
whether it will bend pipes permanently.
I've bent a scaffold pipe permanently by hand. wedge one end of a 10
ft section and walk with the other end,
It really is the worst grade shit imaginable
The tensile strength is low. On the other hand, the strain to failure
is large, which is what you want really.
If you dont mind your poles reaching the pit bottom after a twenty
tonner has gone over.
High strain to failure with low elasticity means plastic deformation,
You want springiness...
Don't be obtuse, you were complaining that scaffold poles were weak, and
I was pointing out that you want scaffold tubes to be ductile.
No, I wasn't complaining they were weak. The phrase was 'the worst
grade shit imaginable' . That is an observation, not a complaint.

You then interpreted that as weak. In the sense of low strain to failure.
That is *your* invention, not mine.

I actually meant they are pretty damned soft and will bend under very
low loads and *stay bent*.

It's the difference between say - piano wire - and a coat hangar.

Scaffold steel is of the coat hangar variety.

Fantastic for bending and staying bent, not much good for bending and
springing back.

I think the correct adjective is 'ductile'.

An elastic band has a higher strain to failure than a steel fishing
line leader. Whether that is a =good or bad quality depends...

You do know what 'strain' means don't you? - how much change in (length)
there is under a given STRESS....




So yes,
Post by newshound
they are not an ideal choice for a cattle grid, you would be better to
make these from a "structural steel" with a higher yield stress. But
OTOH they are more readily available and affordable. If you go to a
steel supplier looking for something with a yield strength of say 350MPa
it's going to be more expensive than random steel scaffold tube (and of
course there is a second hand trade in that too).
--
In a Time of Universal Deceit, Telling the Truth Is a Revolutionary Act.

- George Orwell
John Walliker
2022-01-12 19:15:36 UTC
Reply
Permalink
Post by The Natural Philosopher
Post by newshound
Post by The Natural Philosopher
Post by newshound
Post by The Natural Philosopher
The issue isn't so much deflection (as in flooring calcs) as
whether it will bend pipes permanently.
I've bent a scaffold pipe permanently by hand. wedge one end of a 10
ft section and walk with the other end,
It really is the worst grade shit imaginable
The tensile strength is low. On the other hand, the strain to failure
is large, which is what you want really.
If you dont mind your poles reaching the pit bottom after a twenty
tonner has gone over.
High strain to failure with low elasticity means plastic deformation,
You want springiness...
Don't be obtuse, you were complaining that scaffold poles were weak, and
I was pointing out that you want scaffold tubes to be ductile.
No, I wasn't complaining they were weak. The phrase was 'the worst
grade shit imaginable' . That is an observation, not a complaint.
You then interpreted that as weak. In the sense of low strain to failure.
That is *your* invention, not mine.
I actually meant they are pretty damned soft and will bend under very
low loads and *stay bent*.
It's the difference between say - piano wire - and a coat hangar.
Scaffold steel is of the coat hangar variety.
Fantastic for bending and staying bent, not much good for bending and
springing back.
I think the correct adjective is 'ductile'.
An elastic band has a higher strain to failure than a steel fishing
line leader. Whether that is a =good or bad quality depends...
You do know what 'strain' means don't you? - how much change in (length)
there is under a given STRESS....
So yes,
Post by newshound
they are not an ideal choice for a cattle grid, you would be better to
make these from a "structural steel" with a higher yield stress. But
OTOH they are more readily available and affordable. If you go to a
steel supplier looking for something with a yield strength of say 350MPa
it's going to be more expensive than random steel scaffold tube (and of
course there is a second hand trade in that too).
I walked past a cattle grid today at the boundary of some National Trust
land. It was made from steel tube of about the same diameter as scaffold
pole - maybe slightly larger. The width was about 2.5m and it regularly has
heavy trucks driving over it as it gives access to a building firm. There were
four supports plus the frame at the sides. The supports were in pairs, each
pair being roughly where the wheels of a truck would cross. I have seen
dogs crossing this cattle grid, so its not much use for the OP, but it shows
the considerable amount of support that its designer thought would be
necessary.

John

Andy Burns
2022-01-11 09:44:14 UTC
Reply
Permalink
Post by n***@aolbin.com
How can I calculate what load a scaffold pipe can take without permanently
deforming?
It's not a particularly difficult calculation. I don't have the dimensions or
UTS of scaffold pole to hand, but someone here probably has. Presumably you want
to drive over it? Goods vehicles?
OK I'll bite ... first, calculate the moment of inertia for scaf tube

D = 48.3 mm
t = 4 mm

<https://calcresource.com/moment-of-inertia-ctube.html>

Gives 137676 mm^4

Young's modulus of steel ~ 200 GPa

if we take your 5m width and split it in half, supported at sides and centre
each half has a centred point load 1/4 the weight e.g. a 2 tonne car

500kg 500kg
| |
v v
===============================
^ ^ ^
| 2.5m | 2.5m |
##### ##### #####
##### ##### #####

L = 2.5 m
E = 200 GPa
I = 137676 mm^4
P = 500 kg

<https://calcresource.com/statics-simple-beam.html>

Gives a deflection of 58 mm which is more than I would have guessed, but IANASE
Chris Green
2022-01-11 10:31:21 UTC
Reply
Permalink
Post by Andy Burns
Post by n***@aolbin.com
How can I calculate what load a scaffold pipe can take without permanently
deforming?
It's not a particularly difficult calculation. I don't have the dimensions or
UTS of scaffold pole to hand, but someone here probably has. Presumably you want
to drive over it? Goods vehicles?
OK I'll bite ... first, calculate the moment of inertia for scaf tube
What on earth has the moment of inertia got to do with it? That's a
rotating/dynamic property, a tube of (rather heavy) pastry could have
the same moment of inertia as a steel pipe of the same size.
--
Chris Green
·
Andy Burns
2022-01-11 21:26:43 UTC
Reply
Permalink
Post by Chris Green
Post by Andy Burns
first, calculate the moment of inertia for scaf tube
What on earth has the moment of inertia got to do with it?
It is nothing to do with "inertia" in a moving (or resisting moving) sense, it's
how the shape of the material affects its rigidity in a particular direction
e.g. a square hollow section v.s. an I beam v.s. a round tube ...

<https://calcresource.com/moment-of-inertia.html>
nightjar
2022-01-11 10:40:02 UTC
Reply
Permalink
Post by Andy Burns
Post by newshound
Post by n***@aolbin.com
How can I calculate what load a scaffold pipe can take without
permanently deforming?
It's not a particularly difficult calculation. I don't have the
dimensions or UTS of scaffold pole to hand, but someone here probably
has. Presumably you want to drive over it? Goods vehicles?
OK I'll bite ... first, calculate the moment of inertia for scaf tube
D = 48.3 mm
t = 4 mm
<https://calcresource.com/moment-of-inertia-ctube.html>
Gives 137676 mm^4
Young's modulus of steel ~ 200 GPa
if we take your 5m width and split it in half, supported at sides and
centre each half has a centred point load 1/4 the weight e.g. a 2 tonne car
       500kg           500kg
         |               |
         v               v
  ===============================
  ^              ^              ^
  |     2.5m     |     2.5m     |
#####          #####          #####
#####          #####          #####
L = 2.5 m
E = 200 GPa
I = 137676 mm^4
P = 500 kg
<https://calcresource.com/statics-simple-beam.html>
Gives a deflection of 58 mm which is more than I would have guessed, but IANASE
... and for a 7.5 tonne lorry?
--
Colin Bignell
Andy Burns
2022-01-11 18:51:15 UTC
Reply
Permalink
Post by nightjar
Post by Andy Burns
Gives a deflection of 58 mm which is more than I would have guessed, but IANASE
... and for a 7.5 tonne lorry?
over 200mm (unless you want to assume the tyres from each axle will spread over
two scaffold tubes?)
newshound
2022-01-11 20:50:02 UTC
Reply
Permalink
Post by Andy Burns
Post by nightjar
Post by Andy Burns
Gives a deflection of 58 mm which is more than I would have guessed, but IANASE
... and for a 7.5 tonne lorry?
over 200mm (unless you want to assume the tyres from each axle will
spread over two scaffold tubes?)
With that deflection, it will be spreading over at least three.
n***@aolbin.com
2022-01-11 13:57:12 UTC
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Post by Andy Burns
Post by newshound
Post by n***@aolbin.com
How can I calculate what load a scaffold pipe can take without
permanently deforming?
It's not a particularly difficult calculation. I don't have the
dimensions or UTS of scaffold pole to hand, but someone here probably
has. Presumably you want to drive over it? Goods vehicles?
OK I'll bite ... first, calculate the moment of inertia for scaf tube
D = 48.3 mm
t = 4 mm
<https://calcresource.com/moment-of-inertia-ctube.html>
Gives 137676 mm^4
Young's modulus of steel ~ 200 GPa
if we take your 5m width and split it in half, supported at sides and
centre each half has a centred point load 1/4 the weight e.g. a 2 tonne car
       500kg           500kg
         |               |
         v               v
  ===============================
  ^              ^              ^
  |     2.5m     |     2.5m     |
#####          #####          #####
#####          #####          #####
L = 2.5 m
E = 200 GPa
I = 137676 mm^4
P = 500 kg
<https://calcresource.com/statics-simple-beam.html>
Gives a deflection of 58 mm which is more than I would have guessed, but IANASE
Thanks for having a go, but I don't see why MoI would be relevant ... ?

I didn't describe the proposal well, what I'm thinking of is more like this:


1m Kerb <--------------4m------------------> Kerb
grass Kerb Tarmac Kerb
==================================================
## 2m ## 2m ## 1m ##
## ## ## ##
... so the supports are closer to the wheel track of the heaviest
vehicle likely to need access - 7.5T or, possibly, 18T for removals :eek!

Because of the proposed supports I was more concerned with the tube
being crushed than bending, but maybe that's being naive.

(40 years ago I could have done these calculations :-( )
The Natural Philosopher
2022-01-11 14:04:43 UTC
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Post by n***@aolbin.com
Because of the proposed supports I was more concerned with the tube
being crushed than bending, but maybe that's being naive.
No, scaffold wont crush even with a 30 tonner driving over it. It will
bend though

Its all a bit like renewable energy: Start with a crap idea (there is a
reason why they aren't called doggie grids) add complexity to address
the shortcomings, and end up with a complex expensive mess that doesn't
actually solve the original problem. Bravo!
--
Climate is what you expect but weather is what you get.
Mark Twain
Robin
2022-01-11 15:32:49 UTC
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Post by n***@aolbin.com
Thanks for having a go, but I don't see why MoI would be relevant ... ?
MoI in physics and engineering ain't the same species. For a beam it's
a measure of the cross-section that goes to the stiffness. Sums to hard
for me but...

https://www.engineeringtoolbox.com/area-moment-inertia-d_1328.html
--
Robin
reply-to address is (intended to be) valid
Andy Burns
2022-01-11 18:54:44 UTC
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Post by n***@aolbin.com
Thanks for having a go, but I don't see why MoI would be relevant ... ?
It determines the rigidity of the beam from its cross-section

<https://en.wikipedia.org/wiki/Second_moment_of_area>
Chris Green
2022-01-11 21:35:08 UTC
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Post by Andy Burns
Post by n***@aolbin.com
Thanks for having a go, but I don't see why MoI would be relevant ... ?
It determines the rigidity of the beam from its cross-section
<https://en.wikipedia.org/wiki/Second_moment_of_area>
That's MoA *not* Moment of Inertia.
--
Chris Green
·
Andy Burns
2022-01-11 22:06:45 UTC
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Post by Chris Green
Post by Andy Burns
Post by n***@aolbin.com
Thanks for having a go, but I don't see why MoI would be relevant ... ?
It determines the rigidity of the beam from its cross-section
<https://en.wikipedia.org/wiki/Second_moment_of_area>
That's MoA *not* Moment of Inertia.
It is "Moment of Inertia", aka "Second Moment of Area" don't blame me for
whatever terminology structural engineers use :-)

<https://calcresource.com/moment-of-inertia.html>
n***@aolbin.com
2022-01-10 22:25:30 UTC
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Post by alan_m
Post by n***@aolbin.com
How can I calculate what load a scaffold pipe can take without
permanently deforming?
You could always strengthen it by welding vertical sections of pipe from
the middle of the horizontal pole to the base of the pit.
I propose that the tubes are supported at each end and also at mid-span,
to coincide with the typical wheel track.
Tim Lamb
2022-01-11 10:10:42 UTC
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In message <***@mid.individual.net>, ***@aolbin.com
writes
Post by n***@aolbin.com
Post by alan_m
Post by n***@aolbin.com
How can I calculate what load a scaffold pipe can take without
permanently deforming?
You could always strengthen it by welding vertical sections of pipe
from the middle of the horizontal pole to the base of the pit.
I propose that the tubes are supported at each end and also at
mid-span, to coincide with the typical wheel track.
Umm. If you support at mid span you create a potential path unless the
support is very narrow or hidden below the tubes.
--
Tim Lamb
Bev
2022-01-11 11:19:34 UTC
Reply
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Post by Tim Lamb
writes
Post by n***@aolbin.com
Post by alan_m
Post by n***@aolbin.com
How can I calculate what load a scaffold pipe can take without
permanently deforming?
You could always strengthen it by welding vertical sections of pipe
from the middle of the horizontal pole to the base of the pit.
I propose that the tubes are supported at each end and also at mid-span,
to coincide with the typical wheel track.
Umm. If you support at mid span you create a potential path unless the
support is very narrow or hidden below the tubes.
Also need to think about draining the pit and escape routes for wildlife
such as hedgehogs. Moveable grids are available which avoid the need to
dig and concrete out a pit.
n***@aolbin.com
2022-01-11 12:56:40 UTC
Reply
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Post by Bev
Post by Tim Lamb
writes
Post by n***@aolbin.com
Post by alan_m
Post by n***@aolbin.com
How can I calculate what load a scaffold pipe can take without
permanently deforming?
You could always strengthen it by welding vertical sections of pipe
from the middle of the horizontal pole to the base of the pit.
I propose that the tubes are supported at each end and also at mid-span,
to coincide with the typical wheel track.
Umm. If you support at mid span you create a potential path unless the
support is very narrow or hidden below the tubes.
Also need to think about draining the pit and escape routes for wildlife
such as hedgehogs. Moveable grids are available which avoid the need to
dig and concrete out a pit.
As per initial post:
I'll probably cast a concrete trough to put it in, with one side open to
an adjacent dingle so water and hedgehogs can escape, and so it can be
hosed-out.
n***@aolbin.com
2022-01-11 12:55:47 UTC
Reply
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Post by Tim Lamb
Post by n***@aolbin.com
Post by n***@aolbin.com
How can I calculate what load a scaffold pipe can take without
permanently deforming?
 You could always strengthen it by welding vertical sections of pipe
from  the middle of the horizontal pole to the base of the pit.
I propose that the tubes are supported at each end and also at
mid-span, to coincide with the typical wheel track.
Umm. If you support at mid span you create a potential path unless the
support is very narrow or hidden below the tubes.
Oops, I wasn't clear. I was thinking that the "mid-span" supports would
coincide with typical wheel track ... so there would be 2 supports,
probably 2m apart. The supports would be narrow because they'd only be
making contact with the bottom of the tubes.
nightjar
2022-01-11 17:33:43 UTC
Reply
Permalink
Post by n***@aolbin.com
Post by Tim Lamb
Post by n***@aolbin.com
Post by n***@aolbin.com
How can I calculate what load a scaffold pipe can take without
permanently deforming?
 You could always strengthen it by welding vertical sections of pipe
from  the middle of the horizontal pole to the base of the pit.
I propose that the tubes are supported at each end and also at
mid-span, to coincide with the typical wheel track.
Umm. If you support at mid span you create a potential path unless the
support is very narrow or hidden below the tubes.
Oops, I wasn't clear. I was thinking that the "mid-span" supports would
coincide with typical wheel track ... so there would be 2 supports,
probably 2m apart. The supports would be narrow because they'd only be
making contact with the bottom of the tubes.
How deep does the pit need to be? Could you not just cast a flat base,
put RSJs on top and, if you want to discourage the dog, perhaps weld
tubing or angle iron, V point up to the top. that way, every bit is
supported directly by the base.
--
Colin Bignell
Rod Speed
2022-01-11 19:02:04 UTC
Reply
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Post by nightjar
Post by n***@aolbin.com
Post by Tim Lamb
Post by n***@aolbin.com
Post by alan_m
Post by n***@aolbin.com
How can I calculate what load a scaffold pipe can take without
permanently deforming?
You could always strengthen it by welding vertical sections of pipe
from the middle of the horizontal pole to the base of the pit.
I propose that the tubes are supported at each end and also at
mid-span, to coincide with the typical wheel track.
Umm. If you support at mid span you create a potential path unless the
support is very narrow or hidden below the tubes.
Oops, I wasn't clear. I was thinking that the "mid-span" supports would
coincide with typical wheel track ... so there would be 2 supports,
probably 2m apart. The supports would be narrow because they'd only be
making contact with the bottom of the tubes.
How deep does the pit need to be?
Obviously enough to stop the dog using it.
Big dogs can jump a 6' fence and wouldn’t
have any trouble with a 6' deep pit.
Post by nightjar
Could you not just cast a flat base, put RSJs on top and, if you want to
discourage the dog, perhaps weld tubing or angle iron, V point up to the
top. that way, every bit is supported directly by the base.
Normal cattle grids don’t have any problem working fine with fully loaded
HGVs,

Corse they are fucking great things you need a crane to install.
Peeler
2022-01-11 19:10:50 UTC
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On Wed, 12 Jan 2022 06:02:04 +1100, cantankerous trolling geezer Rodent
Speed, the auto-contradicting senile sociopath, blabbered, again:

<FLUSH the abnormal trolling senile cretin's latest trollshit unread>
--
***@home to trolling senile know-it-all Rodent Speed:
"You really should stop commenting on things you know nothing about."
Message-ID: <pCVTC.283711$%***@fx40.am4>
nightjar
2022-01-11 22:55:30 UTC
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...
Post by Rod Speed
Post by nightjar
How deep does the pit need to be?
Obviously enough to stop the dog using it.
Big dogs can jump a 6' fence and wouldn’t
have any trouble with a 6' deep pit...
I don't think the dog is supposed to get into the pit at any point.
--
Colin Bignell
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