I want to hang a 3x4 I-beam from one end of my shop to the other for a lightweight trolley and chain hoist. It will be suspended by the trusses, which are 2x4 construction, spaced at 24" on center. The beam will run perpendicular to the trusses, and will be centered mid span. The beam needs to hang about 12" down from the bottom of the trusses. Any suggestions on how to do this?

Here's a simple drawing of the structure and positioning:



Sorry guys, the image is full size in Photobucket, but whenever I link to it here it makes it so damn small you cant see crap.

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-Scouder

The trusses aren't made for that.You have to support that beam from the bottom.

It's a 44' span.

.......the beam extend enough to be supported in the walls' cavities with jack-studs?, Rod.

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This trolley will span the entire building. It will be supported at the headers over the loading doors you see in the pictures, and at the ends of the building. The span between the loading doors over the high floor is 44'. The idea is to be able to move things between the mezzanine storage areas, or from the floor to either one. I intend to hang from each truss, so the max load any given truss would see is probably 200lbs.



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-Scouder

capacity of the truss system. That would give you an idea how much weight the system is supposed to handle.

If you do decide to install the I-Beam, I would suspend it from every other truss with long pieces of running thread that connect to the truss via a cross brace up close to the peak. From what little I know about truss construction, I do know they are designed to hold up lots of weight from the peak down; if you put a bunch of weight on that bottom 2X4, I think you would be asking for trouble. 

By the way, your shop looks awsome damn it; I'm green with envy!

Kerry

Kerry,

Hope all is well down there in your neighborhood. With any luck, all this snow won't cause you guys another fiasco like you had a few years back. Fingers crossed.

The trusses are rated at a 10lb/sqft dead top load, 7 lb/sqft dead bottom, and a 40lb/sqft snow load. Works out (40x100 building, 4/12 pitch) to about 5000lbs max distributed load per truss. In my situation, assuming my occasional and temporary point load on the beam is distributed across AT LEAST 4 trusses, and I have a self-imposed weight limit of 750lbs max, any given truss would see less than 200lbs of temporary load. I put more stress than that walking across them. I'm not worried about the trusses taking the weight, and I am VERY sensitive about that kind of thing. My only concern is how to hang the dang thing without alot of fabrication or added weight.

-Scouder

Go with what Kerry said. Suspend it from the top of the trusses near the peak. 200lbs isn't much but you will have to figure in the weight of the track, beam, and trolley. If you try to suspend it from the bottom of the rafters you will be pulling the rafters apart. That bottom 2X4 is keeping the pitched roof from spreading more than supporting actual weight. I would consult a good architect and follow his advice.

I've seen trusses like that piled up with tons of parts, like sozens of drivershafts, empty rear end housings, hoods, fenders and doors.
I think for pulling an engine up and into the loft there wouldn't be a problem but leaving it hanging for weeks might be.

Awesome garage!

Yea, the mountains are all covered with snow, but the real danger is in the spring if it gets to warm too fast. When we had the floods the snow pack was a little above average, but the killer was that it got real warm real fast and then rained.

I would bolt two pieces of angle iron or even 2X4 about 6" below the peak of the trusses, then center a bolt through the middle of the angle iron and hang the 3/8" running thread from that bolt. Then I would drill 7/16" holes in the I beam as close to the center as I could (alternating sides) to the vertical and still use a nut and washer. The running thread will give you the ability to adjust the I beam if you need to and it doesn't cost much either. We buy lots of running thread, strut, nuts & bolts etc. from FASTENAL, they've been the best least expensive source I've found for that sort of thing. 

Kerry

102ft long 4in. beam with dolley supported every 4ft.under the truss,using the same annaligy you did, and it worked fine for 8 years...A simple way to mount the beam,if you want extra peace of mind, run a steel rod, every 4 to 10ft, up to the top point of the truss to pull down,use a 1/4 in steel triangle bolted at the top..BUT....before you go to far, have you considered a forklift, much more versital, with better cost recovery than a steel beam...JMHO JOHN V

n/m

I spent 8 years building custom homes.

While installing garage trusses on morning I stepped off the wall and sidestepped my way across the the bottom chord of a truss to get to the middle of it. I heard a big snap and the next thing I know I'm waking up on the garage slab. The botttom chord had snapped at a knot and broke.

The bottom chord is the part of the truss you are talking about tying into. BTW I only weighed 180 at the time and I also saw my 220 lb. father break a truss in the exact same way. The bottom chords on trusses like yours and the ones that I am talking about are only designed to keep the walls from spreading,The top chords carry all the load and transfer it to the walls.
That is why it is not uncommonon to see trusses with 2X6 top chords, but 2X4 bottom chords...no load on bottom chord.And to make them even weaker,truss companies do have to use the same quality of lumber the Building Dept. requires you to use, they can use Utility Grade lumber, which is crappiest type of lumber available.

How about tying a beam to each wall and runnning an roller mounted I beam between them ?? Getting into the mezzanine would be a challenge tho....
BTW NICE shop...

...I think a better solution would be a gantry crane...(two "A" frames, on wheels, with a trolley on an I-beam between them).

re:

link:

http://www.mcmaster.com/
_______________________________________________________________________________________________________
Steel and Aluminum Gantries
Gantries provide a structural I-beam for handling lifting jobs around your facility. Four swivel casters provide mobility. Conform to OSHA and CMAA (Crane Manufacturers Association of America) standards. Shipped unassembled.
Fixed Made of steel. Casters have polyurethane wheels with roller bearings.
Adjustable The height (A) and width (B) adjust to accommodate different lifts and to make it easier to move the unit through doorways.
Steel have a yellow-painted finish and can handle higher capacities. Height adjusts in 1-ft. increments and the legs pivot for maneuverability in tight places (unless noted). Casters have steel wheels with roller bearings (unless noted).
Aluminum are lighter in weight for easier movement. Height adjusts in 6" increments. Casters have mold-on polyurethane wheels with roller bearings and four-position swivel locks.

It is an easy enough thing to do, but not done correctly, people can die.

Mount nothing to the bottom of the trusses except for the ceiling it was designed for.

Hang your beam from the top of the trusses.

That is all you can do by seat of the pants. Now you need a structural engineer to determing the loads. Not the load you think you will do, but the load tha yahoo after you will do.

Once you have the loads, you will know with sureity what can be done safely.

You may be able to reinforce selected trusses. You may be able to fabricate a truss for your I beam that runs the length of the beam so you effectively have a beam 16 inches tall. This means it can span a good distance without intermediate support. You need a structural engineer to balance all of this out, but I do not see it as a big deal.

You can't use a cherry picker?

A forklift is way more useful and can be used to unload as well as stow in the loft. Looks like you have enough parking space for a small propane unit and one can be had for a couple grand, well used.

My warehouse has 25' clear height. Plenty of room for a gantry crane, etc.

Went with a used Cat 5000# forklift I bought on Ebay. I use it all the time now.

Like others said, trusses are not made for extra weight. Get an engineer involved, and they will tell you "no" since they will tend to want it to be 110% safe.

-Chris H

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There is a post under one end of this I-beam, off the picture to the left, and the saddle was built to hold it from timber beam on the right with four thru-bolts. Then it was determined the small I-beam might be overspanned (13') and the center support was added in the middle. Because the floor joists run parallel to the I-beam a 6 x 6 was utilized to attach to four joists with long lag bolts, hopefully spreading the load. Then there was concern about lateral stress (sometimes we get a little involved when the engine gets 'stuck' in my Mustang) so the angled braces were added. (I'm not a structural engineer and the good folks on this forum helped me determine that I probably was overspanning the small I beam though the answers were a little divergent)



Points you may wish to consider:

Make sure the I-beam is tall enough (cross section) to carry the weight not only to the nearest truss attachement but perhaps spread a little further to each adjacent attachement to spread the load over multiple trusses.

Consider adding lateral support for those events that not everything goes straight up and down as planned. If the I-beam is large enough this is probably a moot point.

I agree with Kerry that the trusses probably carry load better near the top, but it looks like the trusses have a centered vertical member that could be checked for tensile duty.

I-beams are heavy and installing what you propose might be a major undertaking.

I like what some of you guys have for suggestions. Based on that I came up with this:



It is a 2x4 bolted to the apex of the truss, with a 3/8 all-thread passing through it and hanging all the way to below the ceiling. It's about 7' long. Alternate from side-to-side with the mounting on the rail. A 2' piece of mild steel strap from the beam angled up the ceiling about every 8' for lateral support. Now that I look at the drawing, I probably wouldn't have a separate hole and bolt for the lateral support, I'd just put it on the same side with the all-thread and use a second nut to pinch it down on the beam. That will serve a second purpose of keeping the beam from "climbing" the all-thread for any reason.

Any input?

-Scouder

Its good you're engaging the entire thickness of the beam instead of tying into the bottom. Make sure you run some bolt calculations so they wont fail in shear.

...they won't fail with the load I'll put on em. Giggle.

-Scouder

...........Gary B's looks to have mounted/welded tabs to extend the rod/nut outside of the trolley's path, Rod.

Mickey Thompson's 63 1/2 #997 S/S Hi-Rise 427 Lgt/Wgt Galaxie,
1957 C-600 Cab-over carhauler w/390-4V, 2-speed rear-end
FGCofA member #4908
MCGC member #75

"There will ALWAYS be an FE in my LiFE"

I would favor 2 x 6 's instead of the 2 x 4's depending on how wide that "span" ends up being. You can taper the ends where they attached to the truss pretty quickly with a skill saw, and still they will retain good rigidity. Might want to drill the trusses AFTER your framing inspection depending on bolt size.

As Rod C noticed, the bolt heads on my setup protrude a little into the trolley way, but there is sufficient room for a bit of that. Instead of trimming the all-thread in an awkward location could be easier to let the top protrude. Drilling the holes thru an I-beam using a handheld drill takes long, the steel shop might be able to punch those for you if you have the spacing needed. Doing this as a homeowener is a big deal, but for a fab shop it would go quickly.

Gary B

Mounting the 2x4 or 2x6 toward the apex of the truss follows prior discussion, but I don't know that I'd be comfortable with the idea of center drilling 2x4/2x6 at the center point - between the opposing single mount bolts on each end.

To me, it sounds like you'd be weakening the support with the center drilled hole, and then making it the center stress point to carry the weight of the rail and the load as well - which could be cause for center breakage potential - leaving the single bolt on each end to pivot downward during the break.

The lower strap may help defer strain a bit, but I'd think it would do more for side-to-side stability verses the downward force imposed by weight via the bolt through the beam under load, despite the multiple truss tie-ins you propose.

I hope that makes sense...

Don't do that.

Wrap a piece of plate over the ridge.

Make an inverted U to attach to the beam. You do not want the bending stresses on the flanges.

If you must hang from the horizontal 2by, don't drill it, use two of them.

the 'rafters' of the truss with the 2X6. Then use steel plate to bridge the 2X6s. Steel rod through the plate.

My shop's starting to sound puny now, it's only 42x60
I'm in big favor of the fork lifts, I found a '47 Clark Trukloader on craigslist for $500, cute little buggar, it will fit through a 3' doorway, but has a tiny 4-cyl Continental in it. Perfect for moving engines around and loading/ unloading the truck, and I can actually push it around in the shop without starting it pretty easily if it gets in the way (takes up less space than the cherry picker). Strong enough to move a car around too, and then get out from behind it with just a little room. Picked up another cl find, a '41 Ross lift for $600, pretty good sized dual drive wheel rig for outdoor stuff.

Just don't ask any advise from these guys! ww








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2006 John Deer X320 Garden Tractor

This is all wrong.



I'm not an engineer, but I work with them every day. We ship a lot of stuff out of our shop with W6x9 and larger beams.



Don't attach to wood. You're asking for trouble. Those trusses were designed to hold the weight of the roof, the weight of themselves, and the weight of a ceiling with some overage for safety. They were not designed to take the weight of an I-beam, trolley, and chain hoist AS WELL AS whatever is on the other end of the hoist.



If you really want to do the calcs, get the weight of all the roof steel, all of the sheetrock going on the bottom, all the lighting fixtures, and any copper wire/conduit being strung. Don't forget to add the 20 pounds of screws to hold it all together. Find the weight of a cubic foot of snow, multiply by 2 for 24" of snow, and multiply by the square footage of the roof, which is more than the square footage of the floor, generally by about 25-30%. That is the weight imposed on the trusses, not including the trusses themselves, at max capacity. I think you're going to find yourself approaching the weight limit pretty quickly with just the building materials.



The roll-around A-frame is a good idea, the forklift is an OK idea (more to maintain and fuel), but if you still want to get your rocks off with a trolley and hoist, ...



Go with I-beams spanning the width of the area you want to cover, parallel with your wooden trusses, and perpendicular to your center beam. Locate them between the ceiling and your main beam, so the load from your beam transfers to them. Support them from the ends with steel posts to the floor. Now your center beam is clear from the bottom, the wooden trusses don't support anything, and if you size the supports properly, it won't be affected by a point load.



JMHO.



-Dave