Does someone know where I might be able to hire one of those big metal
plates (a cm or more thick) which contractors use when they're doing
roadwork? I mean the ones which, when they've dug a hole outside your
driveway, they put on top of the hole to let you get in and out.
Anywhere in Kent or nearby counties would do.
Cheers,
John
Cattle grids are designed to cope with all normal road traffic. You might
just trouble an old one with an HGV but a 7.5 tonner won't even be an issue.
The minimum British Standard even for private driveway use requires them to
cope with oil delivery tankers up to 26 tons. Highway spec ones will cope
with much heavier vehicles. If the bars are bent on yours then maybe
something really extraordinary once went over it but it'll still be ok for a
small truck.
Even if you could hire a plate as you suggest it would weigh a ton -
literally. An 8' x 6' x 1 inch steel plate would be about 850 kg. You'd
never move it without a crane and I can't imagine the hilarity which would
ensue if you phoned up someone and asked them to deliver, put down and then
take away a plate over your cattle grid because you thought your little
furniture truck might fall through it.
--
Dave Baker
Would it be easier to get hold of 4 railway sleepers and bolt a pair
together side by side on short face for each axle? Then at least when
its done you can use them in the garden afterwards.
I expect if you go into a hire shop and ask for a flat plate to go
over a hole they'll look at you as if you have just landed from
another planet.
Dave
If you can't get that what about scaffold planks?..
Least they'll help spread the load..
--
Tony Sayer
> Does someone know where I might be able to hire one of those big metal
> plates (a cm or more thick) which contractors use when they're doing
> roadwork?
Same place that hires the rest of the big-digger grade kit. You'll
also need their delivery vehicle to get it in place, with a HIAB on
the back.
Scaffold planks or similar would be my first guess too - wood is appropriate
for that sort of one-off.
Though as Dave says, is it just fretting over nothing? How iffy is "very
iffy"? I know to some people that means the entire thing is at the point of
collapse, with bars rusted through and the supports crumbling away. But a
slightly bent bar is no way near that.
Don't know where you are but are these any use?
http://www.site-equipment.co.uk/roadplatesintro.htm
http://www.marwoodgroup.co.uk/category.php?CID=15
http://www.mtmplant.co.uk/search.php?cat=60
http://www.aplant.com/catalogue.aspx?id1=112026
Remember Google is your friend :-)
Cheers
Mark
Also, don't forget that the cattle grid is there for a purpose - if
some poor farmers livestock escape or are harmed by traffic it'll be
you picking up the tab. Remember - sheep are in lamb at the moment so
even slight disturbances can dramtically increase the still born rate.
AWEM
Thanks for this - I had no idea there was a British Standard covering
cattle-grids on private driveways, but I've seen several in rural
areas that are home-made. I actually watched one at a house we used to
own get its bars bent by a removal lorry. After that, even the postman
was afraid to drive his van across it, and eventually I had it
removed, filled in the pit, and put up a gate. As for the oil delivery
tankers, they always waited outside when pumping the oil in!
John
It's at my sister's house and on her land at the start of her
driveway, and there's a gate too. No chance of endangering any
livestock. I will have to ask her about the oil lorries. If they do go
across it to refill her oil tank then I'll be OK.
John
Andara Tool & Plant Hire.
Eltham. 0208 859 2804
Ask for Road Plates
There's a British Standard for just about everything if one does but know
where to look them up. If this government we're afflicted with has its way
there'll be one for taking a dump soon and we'll all have microchipped
intelligent toilets to make sure we're dropping regulation size turds that
won't block the drains.
Anyway, back to cattle grids. The issue is of course not total vehicle
weight but axle loading given that with a normal length cattle grid only one
axle, or maybe just two, will be on it at a time. Even if it is long enough
to have two axles on it they'll be close to either end and so not such as an
issue as weight in the centre. The biggest risk of bending is therefore 3
axle oil tankers which can mass 26 tons in total and 10 tons per axle. 40
ton HGVs will usually have 5 or 6 axles and a lower mass per axle than the
smaller vehicle. A twin axle 7.5 tonner won't have more than about 4 tons
per axle. Almost inconsequential compared to what might drive over one of
these.
If you're worried even a 1" wooden plank will spread a considerable amount
of load amongst adjacent spars of the grid. So will dropping the tyre
pressure of the vehicle because it's tyre pressure that determines the
contact patch size and point loadings. If the tyre pressure is 100 psi then
there must be at least 100 pounds per square inch pressure on the ground.
The tyre sidewall stiffness itself can only add to that. The biggest risk
comes from a heavy vehicle with very high tyre pressures so that the tyre is
effectively solid and all the mass is concentrated on one spar at a time.
Lower the pressure and the contact patch will change to a longer one which
will intersect more than one spar at a time. Do both, plank plus lower tyre
pressure, and you'll float over it like a fairy tripping lightly over marshy
ground. However don't even be worried. Your tiny truck won't hurt it.
--
Dave Baker
On Feb 19, 9:54 am, John Nagelson <johnnagel...@yahoo.co.uk> wrote:
> Does someone know where I might be able to hire one of those big metal
> plates (a cm or more thick) which contractors use when they're doing
> roadwork? I mean the ones which, when they've dug a hole outside your
> driveway, they put on top of the hole to let you get in and out.
Why not fix it?
Pour some concrete in the hole and then prop the bars with some steel or
concrete.
The fact that there is a British Standard is almost irrelevant. I would
be surprised if more than a tiny fraction of cattle grids on private
land had been designed in strict compliance with that standard.
"Dave Baker" <Nu...@null.com> wrote in message
news:gnk9g5$tt$1...@news.datemas.de...
For that matter a a couple of sheets of shuttering ply (one for each wheel
track) would do the job
> There's a British Standard for just about everything if one does but know
> where to look them up. If this government we're afflicted with has its way
> there'll be one for taking a dump soon and we'll all have microchipped
> intelligent toilets to make sure we're dropping regulation size turds that
> won't block the drains.
There is already a British Standard Turd for testing toilet flushes.
However, it looks nothing like a turd (more like a solid rubber tennis
ball) which is presumably why water-saving toilets that won't actually
remove a real one with one flush can still pass.
Pete
Course there is a standard for everything;)..
http://en.wikipedia.org/wiki/Bristol_Stool_Scale
--
Tony Sayer