Gantry for Barn

[SpringHollow]

Well, i finally got a chance to build my gantry for the barn's shop. Took 2 days for a friend and I to build it plus painting time. I had bought some used 20' i-beams a few years ago and welded them up to make ~ 32' long side rails. Every 16", i welded on 3/16" or 1/4" thick (can't remember which) 2" wide flat stock onto the top of the I-beam as hanging tabs. These tabs were bolted through the sides of each truss. The trusses were designed with extra strength to support the gantry load at these locations. Two tabs (one welded about 20% of the way in from each end) were welded centered on the I-beam flange. These were bolted to the trusses first allowing the beam to hang vertically. The other flanges were staggered next to each edge of the beam so that when they were bolted, the beam could not rock side to side. This amount of support was overkill but better to over build, especially for something supporting things above you.

I used the cutoffs from making the 32' beams to make the trolley ends of the gantry. This was bolted with grade 8 bolts to 1/2" x 4" angle iron brackets and attached to the I-beam. Each trolley end was suspended from 2 Harbor Freight 2 ton trolleys with 1" grade 8 bolts. The chain fall trolley is also HF 2 ton trolley that runs on a 22 I-Beam.

Finished it today and works unbelievably nice. Moved 6 loads varying from 600 - 1100 pounds from one corner of the barn to the opposite corner and it rolled effortlessly. I really am quite pleased with how well it is working.

Ken

 

[BearKiller]

Very nice and very useful.

I have a gantry in the plans but I have to get a shop to put it in first, or maybe build the gantry and then build the shop around it.


Do I understand correctly; you have a cross-wise I-beam that rides on the two linear I-beams, and the chain hoists ride on the cross-wise I-beam, right ??

Or do you have more than one cross-wise ??

Thanks.

 

[Groo]

or maybe build the gantry and then build the shop around it.

why waste all that structure? definatly build the Gantry first, unless you was something on wheels.

 

[SpringHollow]

Do I understand correctly; you have a cross-wise I-beam that rides on the two linear I-beams, and the chain hoists ride on the cross-wise I-beam, right ??

Yes, that is correct. I should have taken a picture of the whole thing.

At each end of the crosswise I-beam, the short section of beam that has the two side trolleys on it is just under 4' which means i can get to within about 2' of my garage doors at each end of the building. i can get with in about 18" of the side walls with the chain fall as well.

The load span is about 21' and, if i calculated it correctly, the beam will deflect about 0.4" for 2500 lbs, 0.6" for 3000 lbs, and 3/4" for 4000 lbs if the load is in the center of the span. The heaviest load that i plan on lifting and not at center span is 2500 lbs. If I were buying beams for the cross beam, i likely would have gone with W14x22 which would only result in a deflection of a 1/4" for 4000 lbs. (again, if i am calculating correctly).

Ken

 

[flusher]

Well, i finally got a chance to build my gantry for the barn's shop. Took 2 days for a friend and I to build it plus painting time. I had bought some used 20' i-beams a few years ago and welded them up to make ~ 32' long side rails. Every 16", i welded on 3/16" or 1/4" thick (can't remember which) 2" wide flat stock onto the top of the I-beam as hanging tabs. These tabs were bolted through the sides of each truss. The trusses were designed with extra strength to support the gantry load at these locations. Two tabs (one welded about 20% of the way in from each end) were welded centered on the I-beam flange. These were bolted to the trusses first allowing the beam to hang vertically. The other flanges were staggered next to each edge of the beam so that when they were bolted, the beam could not rock side to side. This amount of support was overkill but better to over build, especially for something supporting things above you.

I used the cutoffs from making the 32' beams to make the trolley ends of the gantry. This was bolted with grade 8 bolts to 1/2" x 4" angle iron brackets and attached to the I-beam. Each trolley end was suspended from 2 Harbor Freight 2 ton trolleys with 1" grade 8 bolts. The chain fall trolley is also HF 2 ton trolley that runs on a 22 I-Beam.

Finished it today and works unbelievably nice. Moved 6 loads varying from 600 - 1100 pounds from one corner of the barn to the opposite corner and it rolled effortlessly. I really am quite pleased with how well it is working.

Ken

Nice job.

Technically speaking, I think what you built is a bridge crane if I interpret your photos correctly.

A gantry crane is similar, but is supported from the floor on casters. Here's mine



It's a 1-ton model from Harbor Freight. It's OK, but I'd rather have your setup.

 

[BearKiller]

Nice job.

Technically speaking, I think what you built is a bridge crane if I interpret your photos correctly.

When I worked at Norfolk Southern, they had a similar set-up in the car-shop that could pick up a loaded box-car and carry it across the building; I don't know what we should have called it, but everyone there called it a "gantry crane".

On your HF gantry, did you add those base extenders or did they come with the kit ??

Also, if you were to hang a 6BT Cummins on it, can you then roll the whole outfit forward or back, like one would need do when swapping an engine ??

Thanks.

 

[Scooby074]

I have a 10' gantry crane.

I use it all the time,however mine is permanently bolted to the floor which as i now know limits its flexability. I decided on bolting it to the floor so i wouldnt have to deal with tripping over (and the space taken by) the extended legs.

So i have making it height adjustable ( so i can move it to the other side of the barn) and mounting it on wheels (as soon as i round up some decent casters for the right price) on my list of things to do.

Youll love your crane and wonder how you got along without it.

 

[flusher]

When I worked at Norfolk Southern, they had a similar set-up in the car-shop that could pick up a loaded box-car and carry it across the building; I don't know what we should have called it, but everyone there called it a "gantry crane".

On your HF gantry, did you add those base extenders or did they come with the kit ??

Also, if you were to hang a 6BT Cummins on it, can you then roll the whole outfit forward or back, like one would need do when swapping an engine ??

Thanks.

I added those extenders myself so I could move the gantry around with a load on the chain hoist. So, yes, I can move the gantry back and forth with an engine hanging on the hoist without worrying about the thing tipping over.

That HF gantry comes with cheesy 5" dia plastic wheel casters. I replaced these with 5" cast iron wheel casters from McMaster Carr ($25 ea). The hole pattern on the replacement casters fortunately matches the pattern on the plastic casters perfectly.

 

[jimmer2880]

I'll be watching this thread closely. I have a 32x32 garage with 12' ceiling and want some sort of overhead hoist.

My current plan is to make something on wheels, ~12' wide. The other option is to try to find a beam strong enough to span the 32' width, that is still small enough for me to raise 12' high to install it. What I don't like about the fixed beam, is that all lifting must be on the same plane, whereas with the portable one, I would have much more lifting location options. Of course, with anything portable, there is the extra work of making it portable, but still stable, and having it in my way when I'm not using it.

Of course, there are currently 0 dollars set aside for this project, so it's still just a pipe dream

 

[SpringHollow]

If i did my calculations correctly, i think a W14x22 would deflect about 0.62" over 32 feet if loaded with 3000 lbs in the center.

Ken

 

[mlauk]

If i did my calculations correctly, i think a W14x22 would deflect about 0.62" over 32 feet if loaded with 3000 lbs in the center.

Ken

You would also have to add the weight of the beam which will deflect .09 inches by itself.

ksimolo, nice job, what size beam did you use on yours?

 

[SpringHollow]

I thought those values took into account their own mass. Shows what i know. I used W10x15 So for the loads i quoted, one would have to subtract 300 lbs to get the live load for that deflection. I have not calculated a failure point for my setup.

Ken

 

[SpringHollow]

Actually, if the weight of the beam is not in the values used, one would subtract less than the 300 lbs because the beam is not a point load.

Ken

 

[mlauk]

Actually, if the weight of the beam is not in the values used, one would subtract less than the 300 lbs because the beam is not a point load.

Ken

To get the deflection of just the beam, I used the formula for Simple Supports for a Uniform Load, not a point load. So with the W14x22 and a 32 foot span, the beam just hanging there would have a maximum deflection of .09 inches at the center. Any additional load would cause it to deflect more.

 

[mlauk]

Actually, if the weight of the beam is not in the values used, one would subtract less than the 300 lbs because the beam is not a point load.

Ken

For W10 x 15 and a 21 foot span, I get a maximum deflection of .033 for the weight of the beam itself using the uniform load calculation. It doesn't affect your situation much, but with a heavier beam and a larger span it starts to factor in.

 

[chriswheeler]

Very nice work. For safety sake, when you are done, do a load test. Easy to do, center the whole thing with the trolly in the center of the beam. Rent a load cell if you don't have access. Load to 125% of what you are going to rate this thing to lift. Generaly chain falls will do this, 25% above their rateing. You'll thank yourself not having to ever wonder if something might ever come down at a bad time. Use a tractor or anything else that is properly rigged for a dead man between the load cell and the chain fall. Stay well clear during the test, leave the load suspended at 125% for at least 15 min. Your work looks good and more than stout enough, but I've had the misfortune to witness some bad accidents with this stuff, test is good insurance.
Chris

 

[SpringHollow]

Hi Chris,

That is very good advice. The heaviest load i expect to have is a one time load of 2500 lbs. So i will stand far to the side when lifting that. If that holds, then i should be fine. So far, at 1100 pounds, it rolls extremely easy in all directions.

The other load test i had thought about was lifting my tractor at about 4000 lbs. That would have been neat just for the visual effect and a nice way to add air to the inner duals. But I am a wimp and believe in overbuilding and underusing.

Ken

 

[jimmer2880]

Thank you for all of those calculations as to what size beam I would need. I wasn't expecting those. Now, for the dumb question. How much would that beam weigh? Before deciding to go with such a beast of a beam, I would need to determine if I could get it up there once I bought it.

 

[SpringHollow]

The first number is the depth of the beam, the second number is the weight per foot.

So W14 x22 is 14" deep and weighs 22 lbs per foot.

Ken

 

[MichiganIron]

The allowable stess falls rapidly depending on the unbraced length of the beam top flange. The beam will fail in lateral-buckling before it fails in bending, especially in a configuration like a bridge crane. It is dangerous to use elastic stress analysis without taking into account the allowable stress reductions for the un-braced length. For a W14x22, the allowabale stress needs to be reduced for unsupported lengths over 5.6'. In other words, the W14x22 used as a bridge crane beam for spans over 5.6' will fail due to lateral buckling, not bending.

The allowable stress for a W14x22 spanning 21' between lateral supports has an allowable stress of 5.7ksi, which is approximately 25% of the allowable stress for the same member laterally supported at 5.6' intervals, assuming A36steel.

Reference AISC (American Institute of Steel Construction), Allowable Stress Design, 9th edition.

Hope this helps