Technical Question On CrossBeam Support for Trolley System

[2oolhound]

I'm looking to install a trolley over my storage attic in my small garage. The span is only 8' and the average weight I'd lift is about 500lb. but rarely would need to go over that. There are heavy ledgers running the length of the garage along the walls that I want to put 8' 3x4x1/4" tubing across to hold a small (4") I beam for a very small trolley. There will be 4 cross beams over 18' to suspend the I beam from.
I'm using recycled material I've salvaged from a set of HD industrial racking.
This is one of the 10' cross beams I have which will be cut down to 8'.

I'll be cutting off 1' from each end which eliminates the holes drilled near the ends but there is one 1" hole through the beam at dead center. How detrimental is this? Can I fill it with weld or weld a scab over it to restore the strength of the beam? Any other suggestions welcome.

Thanks!

.
.
.

 

[bigguns69]

The 1" hole at the center of the length at the top or bottom of the beam is at the highest stress point of the beam. At 500 lb., that is a small load for that length and cross section size. Weld the hole shut if you want and you will be plenty good. Honestly, you don't need to fill the hole for that size of load.

 

[2oolhound]

Thanks for the info! The 1st beam is in place (with the hole open). My gut instinct says it's ok too BUT what do I know. A second opinion is re-assuring and appreciated!

 

[BD1]

I would add a vertical uprights 2x4's from the roof rafter down to the ledgers.
There should be collar ties on the roof rafters . If not add those too.

 

[matt_i]

I would put the drilled hole on the top side of the beam. The top flange is in compression. You can either attempt to plug weld it or just scab over it with a welded patch. If you are supporting every 4-1/2 feet or so it won't be nearly as big of a deal.

Watch your connections steel-to-wood. I like to use the GRK-RSS screw 5/16" nominal in a shear orientation (basically flat or angle iron and a drilled hole where a massive overload would attempt to shear the screw off, vertically down).

 

[kbs2244]

You are over-engineering it!
You loads are light and the span is small.

You will be fine.

 

[2oolhound]

I would add a vertical uprights 2x4's from the roof rafter down to the ledgers.
There should be collar ties on the roof rafters . If not add those too.

These ledgers hold the roof rafters. The roof is flat but slightly sloped so these run between the rafters. They will sit on a vertical upright of the same material and that will sit on another ledger but the vertical continues below that lower ledger to the ground. It's only an 8' span so it sounds like I have nothing to worry about.

I would put the drilled hole on the top side of the beam. The top flange is in compression. You can either attempt to plug weld it or just scab over it with a welded patch. If you are supporting every 4-1/2 feet or so it won't be nearly as big of a deal.

Watch your connections steel-to-wood. I like to use the GRK-RSS screw 5/16" nominal in a shear orientation (basically flat or angle iron and a drilled hole where a massive overload would attempt to shear the screw off, vertically down).

The hole is top and bottom but the span is slightly less than 8'.

You are over-engineering it!
You loads are light and the span is small.

You will be fine.

Thanks! That's the reassurance I was looking for.

 

[2oolhound]

UPDATE:

Here is where I was at in the beginning, I was tossing all my salvaged steel up in the attic. The more I accumulated the more I braced the attic floor to prevent sagging until the problem became that I couldn't fish out the pieces I needed as they were buried.

The top roof was supported on the sides by rough cut 2" x 14" beams along the sides and there was a full sized 2" x 4" ledger attached to that which held up the 2x4 rafters on 16" centers (the span is just under 8' so plenty strong). On the bottom of the pic below you see the mezenine floor rafters which are supported by the same beam and ledger system as the top roof. Upright posts from the ground support these beams and ledgers but in this photo I have removed most the top upright posts as they weren't holding any weight and they were being replaced with steel ones.

Here is one of the upright posts which supports the top wall beam and ledger. The top is in the foreground and the tab on the utmost top will join a steel cross beam to the top of the post on the opposite side. At the top of the photo you can see the base that bolts to the lower steel cross beam that spans the floor and rests on the lower wall beams on each side. This way the 2 upright posts opposite each other form a rectangle with the lower steel base and the upper steel beam. There are 3 of these rectangle structures.

Here is the post in position. The other 2 rectangle structures are seen behind but the horizontal arms to hold steel stock have not been welded on yet.

This photo shows the full front rectangle with the horizontal support arms on both sides. Also you can see the top steel cross beams that tie the opposite posts together. In the center of these top beams are drilled mounts to hold an I beam for a trolley which I will add eventually. There is a length of 2x4 steel tubing up there now that I temporarily mounted a winch to.

The only problem is I went and used most of my steel stash to build the darn thing and there's not much left to store in the system