I Beam Trolley Mounted Chain Hoist for Implements -- What size I Beam?

[SmallChange]

I have a pole barn with roof trusses and want to attach an I beam up to the bottoms of the trusses to run my hoist and trolley across the trusses (that is, I beam perpendicular to trusses and parallel with roof ridge). The purpose is to make it easy to lift and move 3 point and skidder mount implements, which weigh less than half a ton, with the 1 ton chain hoist. My floor is uneven and tilted, and wheeling them around would be tough. I'm pretty sure this weight spread over multiple trusses will be OK; after all, four big men standing on the roof shouldn't make it collapse. Also, both ends of my I beam will be anchored to stud walls.

But how big an I beam to use? I'm thinking one of these:

S 4 x 9.5 lb (4.00" x .326" x 2.796")
S 5 x 10 lb (5.00" x .214" x 3.004")
S 6 x 12.5 lb (6.00" x .232" x 3.332")

These are all A36/A572-50 Standard Steel I Beam, and the dimensions are height by center web thickness by total width across flanges. My hoist manual says it will fit all these.

With the beam anchored to each truss, or more likely to a heavy board such as a joist laid the strong way across the trusses, it's not like it has to support the load at its center when itself supported only at the ends. It's got distributed support. My feeling is that even the 4" one would be more than strong enough.

What do you think?

Thanks!

 

[Shaneard]

I would think the 4" would be enough as well, just be sure and don't overdo it.

 

[countrybumpkin]

Weight pushing on the top of the roof, and weight suspend from the bottom of the trusses are not the same. You need to find out the truss specs to see how much, if any they can hold. I wouldn’t try to attach it to them anyway.

 

[herm0016]

you could sheet the center of every 3rd or 4th with plywood or sister a 2x along the bottom chord of ever few trusses and attach to those just to be safe.

I am sure you will be fine either way though. 4 in beam should be great, just make sure the trolley fits it.

 

[CincyFlyer]

I always like a beam on two columns, stand alone, no reliance on the strength of the roof structure.

 

[Reb954]

Below will give you an idea of rated capacity of the various beams over various spans. I also would not rely on just attaching the beam to the trusses. The beam should have it's own end supports.

 

[the old grind]

Rather than attach AT any single truss along the beam I'd bridge across/atop the truss' bottom chords and suspend the beam at points hung between the trusses vs TO them. Micro-lam or similar for strength with some 'give' is the only thing I'd add then to the minimum imagined. Go full length maybe, depending on I-beam length, truss spacing, # of 'hangers' holding it up, etc. No amount of beam flexing under load, or oops, would put a load onto a single truss. Two to four instead, anywhere along the beam. Support gained from ends depends on beam's height, wouldn't account for sag under its own weight if long enough.

Weight of tackle has to be considered, as do unsupervised mishaps. Except under those attachment points loads would be across 4 trusses at a time. My thoughts are to maximize reserve capacity. I've had half a 4x4 x 8' land on my head when an unexpected 'jerk' in a helper's hasty rigging caused a rapid 1" or so of load 'settling' while on the chain and luckily with my end of load only 6" from floor. The crossbeam snapped at an unrecognized weak point and were it not for the sharp point at the top my head I could have taken a serious lump from the 4' piece that hit my shoulder even harder on the way down. :2cents:

 

[SmallChange]

Below will give you an idea of rated capacity of the various beams over various spans. I also would not rely on just attaching the beam to the trusses. The beam should have it's own end supports.

View attachment 614142

Hey, nice table, thank you!

I think everybody has won me over, this needs support at its ends. I think I'll anchor a vertical 4X4 to each of the end walls with its base in a concrete footer, and the beam will sit on these. I will attach it to the trusses, too, so it will be very sturdy in all directions.

The table doesn't show the 4" size carrying a load over 10 feet, so I upped it to the 5" size. Let the margin for error be bigger, you know? That said, it is supposed to be good for 6,000 lbs (this is the 10 lb per foot version of 5" I-beam).

Considering what bridge cranes go for, I think this one, which will amount to maybe $500 by the time I'm done, will be a decent bargain. Of course, I have to add my labor for free to make that true....

 

[Rustyiron]

Don't do it!
At least without the blessing of the truss builder and his corrective strengthening you'll have to perform. They (the bottom chord) are usually designed to only work in conjunction with the rest of the truss members to support the roof & any snow loading and some insulation and interior finishes, ie; drywall or other finishes, not any additional loading.

 

[Industrial Toys]

I would agree, not to use any one truss for lifting, but he is spanning all the trusses. He should be able to lift a modest amount without fear.



I bought that air hoist at an auction and for lack of a better place to store it, I hung it in my garage since I have no lifting facilites there and can't get a loader in there. There is a 2X10 spanning the joists. There is also a heavy steel plate on the top side of the 2X10 that the eye bolt goes through. I used it to lift my Mule, and didn't hear as much as a creak. I have a warning on it, saying NOT FOR LIFTING. You have to use common sense.

One thing I have noticed is that in commercial steel framed buildings, the bridge cranes are always seperate from the structure. You would think, they could just beef up the building frame, but they don't.