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How to tell load capacity of aluminum ramp?

Cannonmn

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Jun 25, 2016
A tenant was evicted from nearby warehouse and I bought the stuff left behind from the landlord. One item was this new-looking aluminum ramp. Sry I dunno the number of that aluminum and the ramp is devoid of markings of any type. If you can ID this ramp as a commercial product, I’ll just find out what rating the maker gave it. I’d think as new as it looks, if a production piece, there’d be an info plate, but there isn’t, so maybe shop-made? Ramp measures 82.5 x 42.5”, tread plate is 1/4” thick, curbs above tread and stiffeners below are all 2” high x 5/16” thick. The evictees also had a dead weight on a skid they may have used to test the ramp but that’s wild speculation. Weight is marked 1120 kg, made of ten 1” steel plates forming a block 43 x 23.5 x 9.5”. D7A1FA74-8EC3-4AC2-8127-C28C1EAE9DF3.jpgE376413B-378F-4960-B3C6-B64C88A0C3C7.jpg02F846E4-06E6-4C88-B2D8-899479A76A91.jpg
 
Probably not a commercial product, except maybe as a prototype. Capacity largely determined by the dimensions of the curbs and the stiffeners below. If I had nothing better to do, I'd draw it up in CAD and run it through an FEA program.

Aluminum tread plate could be lots of things, most common might be 3003 or 6061, the latter about 1.5x-2.0x the strength of the former. If you determine capacity by deflection, material yield strength not really relevant. If you determine capacity by collapse/safety-factor, material yield strength very significant.
 
Thanks, may be worth doing quick dirty experiment. Support both ends solidly so ramp is horiz. and a foot off floor and suspend the 1120 kg weight just over ramp from chains with turnbuckle and scale, both in series, so weight could be lowered onto ramp with fine adjustment and force on ramp measured. Set dial indicator with large range under middle of ramp to record deflection. Record and graph turnbuckle turns and measured deflection vs. force so I can tell by resulting curve if ramp is “holding” or likely to continue to deflect near failure. I’m thinking a total deflection of about an inch or two might be ok if the curve was flat or nearly so at that point; if not then 1120 kg load is over ramp’s capacity so remove 2 of the 1” plates from weight stack and try again. Record all on video of course, just because that’s easy to do. Think I’d have to allow 1/2 Man-day to set up and do this accurately.
 
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something of that length, once you see much more than 3/16" of deflection when supported at each end... that's when you know your near failure, so deduct about 500 lbs from that and you have a safe working load limit, I'm by no means an engineer, but I have been designing and engineering things for the last 30 plus years.
 
something of that length, once you see much more than 3/16" of deflection when supported at each end... that's when you know your near failure, so deduct about 500 lbs from that and you have a safe working load limit, I'm by no means an engineer, but I have been designing and engineering things for the last 30 plus years.

Thanks, I can work with that, will make the experiment a lot quicker to set up and complete. I’d be very happy if that ramp would safely support the 2400 lb. electric pallet jack with 1000 lb. load on it, but looking at the “truck end” of the ramp, one small ear sticking out on each side, it wasn’t designed for that kind of use.
 
8DBA85D2-FA4B-48CC-874E-A84DF5440E51.jpgSince I’m already sure this ramp won’t safely hold my desired 3400-lb. load due to the small ears at the end, if nothing else, here’s my plan to improve it.

I’d get some steel H-beam per: W 4 x 13 lb (4.16" x .280" x 4.06") at $234. Per 20 ft. and put a pair of brackets on either end of the ramp to hold two steel beams running the length of ramp on each side. I’d contour the truck end of the beams to fit my truck’s ass end. I’m using steel beams vice aluminum to ensure I can contour truck end and still have enough strength, plus having steel reinforcement in this makes me more comfortable. Made so steel beams are easily removable so the 3 parts of ramp can each be carried by one man. Yes I’ll test it again when I’m done. Opinions?
 
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