strength of aluminium channel

[Jack p]

looking to make a set of aluminium ramps similar to what they use for loading machinery,i would like the profile to be as small as possible and i have found some manufactures that say they can supply a set with a profile height of 120mm that will support 3ton at a maximum span of 3500mm what wall thickness would this need to be ? they consist of two c sections per ramp with aluminium plank extrusion welded between them to give the width.

could it be made from 100mm profile c section with maybe 3 lengths to compensate for the profile reduction as i only need them to support a max weight of 2.5t so 1.25ton per ramp at 3500mm they will be a similar design to the picture

 

[slim_boy_fat]

Those look like I section

 

[Jack p]

Those look like I section

yes,i said they would be similar design to that,just to give an idea of what im trying to achieve

 

[CompoSimmonite]

If "homemade" so no stress / weight testing that a professional pair would have then I'd overengineer or follow what is already proven to be safe - same as ones in picture. It's the depth that gives strength so would stick with 120mm I section

 

[Jack p]

If "homemade" so no stress / weight testing that a professional pair would have then I'd overengineer or follow what is already proven to be safe - same as ones in picture. It's the depth that gives strength so would stick with 120mm I section

yes i agree with what your saying ideally i would like them to be 100mm as they would fit in the ramp holders on the trailer without modification,if i was to add an extra length in the centre do you thing that would be enough to compensate for the reduction in height?

 

[smashweld]

as said prob easier to copy a proven design

these are 85 deep, 3000mm span 2000kg capacity so with the right design I'd think 100mm depth for 2.5ton is possible....(edit...maybe not, see post below)

https://www.spaldings.co.uk/vehicle...um-loading-ramps-c85-30-345--1-pair-(2-000kg)

I'd get a good look at how theyre made though, looks like shs for the 'rungs' on this one? https://www.rampcotrading.co.uk/catalog/product/gallery/image/1066/id/243/

is steel out of the question?

 

[smashweld]

also, make sure the ones for track machines aren't different design to ones meant for vehicles with wheels

these are all 100mm

http://www.theramppeople.co.uk/vehicle-ramps/profile-height-up-to-150mm/trp100-series

1750 capacity for 3500mm span...hmmm

if I was to quasi it...I'd think 1750/2 (capacity it states in that web page above for 100mm depth 3500mm span) to get the weight one I beam would take, then x3 to see what 3 would take. But no idea really.......how much strength comes from the 'planks'? etc

it will be possible 100mm depth with the right design but might need a lot of material...

 

[hareng]

I would price up the cost of the channel, first one found even four lengths of 4"x1x1/4" available 5m lengths at £90 each plus shipping £18 (£430). Should save 25% on that if buy cut to length.
Above links start at £600.

 

[smashweld]

1750/4 I meant in that last post btw....ramblings..

here's another company .......100mm depth 3500 span 2750kg load

http://www.therampcompany.co.uk/small-lorry-ramps/

 

[fizzy]

Remember you can beef ramps up considerably by using a jack and a big baulk of timber underneath half way along. The ones I have are rated at 2.5 tons but we have had 5 on there!
The ones I have look very much like the ones in the picture. I bought them on Ebay for £300 - never been used.

 

[Jack p]

as said prob easier to copy a proven design

these are 85 deep, 3000mm span 2000kg capacity so with the right design I'd think 100mm depth for 2.5ton is possible....(edit...maybe not, see post below)

https://www.spaldings.co.uk/vehicle...um-loading-ramps-c85-30-345--1-pair-(2-000kg)

I'd get a good look at how theyre made though, looks like shs for the 'rungs' on this one? https://www.rampcotrading.co.uk/catalog/product/gallery/image/1066/id/243/

is steel out of the question?

its not but we are trying to keep the weight down to make man handling them easier as they will be used frequently,from what you've posted so far i should be alright at 100mm but the thickest i can get from my supplier is 6.4mm do you think that would be ok? its double the thickness i would use if doing it in steel

 

[fizzy]

http://www.ebay.co.uk/itm/10ft-Alum...489247?hash=item3f818dbc1f:g:AcYAAOSwKoRZY0zx

http://www.ebay.co.uk/itm/Heavy-Dut...874272?hash=item3aea2c4a20:g:PK0AAOSwEUVZYmJZ

I would keep my eye open on ebay in the auction section. New ones are silly money!

 

[smashweld]

its not but we are trying to keep the weight down to make man handling them easier as they will be used frequently,from what you've posted so far i should be alright at 100mm but the thickest i can get from my supplier is 6.4mm do you think that would be ok? its double the thickness i would use if doing it in steel

I really dunno, you need something like 3 times the amount of alu to match the weight steel would take for the same deflection.(if the spec was that it wasn't allowed to bend at all it would be just as heavy with aku than it would with steel...but would be stronger overall)..but some deflection is fine with ramps, altho alu will crack after it starts bending sooner than steel would. That prob doesn't help....

I've learned recently (after wasting hours trying to work out the kind of thing you're trying to) that copying is best, especially with things like this that companies already have made/tested.

Other way is to over engineer but could get pricey with alu

 

[CompoSimmonite]

What about grating planks for centre http://www.pcpgratings.co.uk/planks.html https://www.prmetals.com/plank-grating/c/13/

 

[hareng]

Remember some fellow workers set PCP Gratings up in 1984 after the demise of Bettles, mrs worked at Ever Ready opposite.
Type 2 2.5m long would weigh in around 12kg each according to specs dubious. Stronger and a bit lighter is the USA pattern plus available in aluminium probably to order. Both are used for ramps with additional support.
Worth a call its been 23 years since had dealings with them now bought out and forgot the BS specs, it may well be aluminium grade 5083 which has a lot of give before any cracking but not as good as 6082.

 

[Brad93]

You're only gonna get extrusion in 6082 or 6063 easily. 5000 series is rare.
Welding reduces its strength by up to 40% in the HAZ.

You don't want to be welding too much into it for that reason.

I've got riveted aluminium ramps rated at 5000kg each.