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Safe load on Aluminum I-beam?

richard newman

Titanium
Joined
Jul 28, 2006
Location
rochester, ny
I have access to a 13' length of 8" x 5" x .230" I-beam, 6061 aluminum. Wondering what the safe load would be configured as in the drawing? I studied this kinda stuff 55 years ago, but never used it and it's long gone...

Application would be a small traveling crane for lifting wood into a 13' high access door.ibeam dwg.jpg
 
This sounds like a W beam. 5" wide flange on an 8" tall .230" web beam does not sound like the kind of thing you could run a trolley on to make it "travel".

I have an old 250 lb electric hoist on a little trolley running on a 12' piece of 4" x 2" junior beam. I would feel safer about that lifting a load than the 6061 beam. Atleast the steel will bend first.
 
No trolleys, the crane itself will be on wheels and roll back, similar to what's used to hoist stuff up on roofs. The "anchor" at the end of the 8' leg will be my electric pallet jack, which will also provide locomotion.
 
No target weight , as much as is safe. I'm moving to a new building, 2nd floor space, and an elevator that can't handle any lumber over 10'. Will take my machines, but I have a fair amount of 10' - 14' hardwood. Would prefer not to lift it up by hand, boards up to 4" thick. Crane service can't poke it into the 8' x 8' doorway.

Smooth concrete floor, or I'll put down 1/8" steel plates. Just need to move far enfu in to clear door, and then set down on dollies.
 
I'd recommend the online calculators to get some ideas about safe loads. I don't know what your plan is to marry the beam to the electric pallet jack, but the addition of some sort of diagonal brace under the beam end that (I'm guessing) is going to poke out into space as the business end will minimize the potential risks of overload. Ever since I looked at the data for deflection vs. yield for steel compared to aluminum, I have lost interest in making lifting gear out of aluminum.
 
Try some of the calculators, or just load the beam on a couple of 4x4's at each end on the ground, then load the center with whatever weights you have available. Observe deflection, figure out what you're comfortable with, then test your setup fully configured with that load for confirmation, including behavior while moving.

Just be sure that you're safe, including constraining the beam ends such that if it does fail, it can't slide back and whack you.

And have a person videoing the moves. If nothing else, never waste good Youtube material...
 
Ever since I looked at the data for deflection vs. yield for steel compared to aluminum, I have lost interest in making lifting gear out of aluminum.
This is one reason I'd never buy one of the aluminum "racing" pump jacks sold by discount stores. Not going under a car without good jackstands, but don't want to drop it during lifting due to jack failure either.
 
My FIL bought one of those gogetamuss "billet" aluminum trailer hitches when he bought his new Duramax a few years ago. I wasn't as excited about that hitch as he was. First time he used it he was hauling his 8x14 dump trailer. Hitch snapped right off going down his steep driveway. Wasn't going 2 MPH I bet. The trailer pushed the truck down the hill and a big tree stopped the whole mess from going off a ledge.

Aluminum has it's place, but maybe not great for everything.
 
I have access to a 13' length of 8" x 5" x .230" I-beam, 6061 aluminum. Wondering what the safe load would be configured as in the drawing? I studied this kinda stuff 55 years ago, but never used it and it's long gone...

Application would be a small traveling crane for lifting wood into a 13' high access door.View attachment 382614
I assume that span is equal at each side of the support (i.e. 6.5 feet). The section modulus for the beam is 14.9 inches squared. Assuming T6 6061 aluminum, the yield strength is 5076 psi.

Based on those numbers the beam yields at 970 pounds. That is based on a point load at the end. This also does not consider any non-vertical loads, torsional loads, non-static loads, or the potential for beam buckling.

I don't know what factors of safety are typical with aluminum in this use. At a minimum, I suspect a factor of safety of 2 would be wise. That would give you an allowable load of about 500 pounds, but considering the other factors it could be significantly less.

This information should give you a rough ballpark. Proper calculations and design guidance should be used to determine the actual safe load.
 
I think that the math is much harder then folks have realized. Those load tables are for horizontal beams or some few for vertical. You are making a teeter toter. How steep an angle will it be? Maybe 45 degrees up for a ramp to the second floor.
You need some kind of load spreader at the rocking point so it is not a needle bearing which can cut into the beam and deform it. That joint needs to have some very positve holding means so the entire thing does not slip down and slide off the support.
Your trolley would probably slide downhill if you use brakes only engaging the beam. Railroads max out around 5% grades until they have to use cables or gear racks.
Bill D
 








 
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