Maximum Load for a custom steel sawhorse
Maximum Load for a custom steel sawhorse
(OP)
We have custom made steel channel/angle sawhorses in our shop. They are used basically to hold up heavy steel plate, typically 2 under each plate. I want to conservatively "rate" them for a max. load that each one can hold by assuming a uniform load across it. They are constructed of a horizontal "C" channel at the top with "A" frame angles at each end. Some even have bracing under the "C" channel along its length as pictured.
Can someone help with the proper beam (Roark's stress and strain) formulas needed to analyze this?
I'm thinking it will fall under a BEAM that is simply supported at each end, but I don't know if I should check the design with other formulas.
Can someone help with the proper beam (Roark's stress and strain) formulas needed to analyze this?
I'm thinking it will fall under a BEAM that is simply supported at each end, but I don't know if I should check the design with other formulas.





RE: Maximum Load for a custom steel sawhorse
I'd probably want to test one of them...
RE: Maximum Load for a custom steel sawhorse
rp
RE: Maximum Load for a custom steel sawhorse
Thanks for the comments.
RE: Maximum Load for a custom steel sawhorse
Once you have placed the plate horizontally on the horses, the channel on top is not nearly as stiff as a heavy plate, so it's really not loaded at all until the a-frames start to buckle and the diagonals get some tension or compression. Okay, the channel flanges get some direct compression, depending on the corner details.
If everything is placed symmetrically, the plate is basically supported by the four a-frames.
How about farming this out to a college junior or some FEA junkie?
Mike Halloran
Pembroke Pines, FL, USA
RE: Maximum Load for a custom steel sawhorse
The small frame would require analysis of beam bending, columns strength and welds. FEA model or 2x what proof load of that you are loading it to now..
RE: Maximum Load for a custom steel sawhorse
If you have a load meter on your press brake, just set one on the brake, and keep increasing the load until it buckles, then back off 50% for the rest. You will have your answer before the FEA guy has loaded the problem.
B.E
The good engineer does not need to memorize every formula; he just needs to know where he can find them when he needs them. Old professor
RE: Maximum Load for a custom steel sawhorse
RE: Maximum Load for a custom steel sawhorse
And loading on the legs to account for getting whacked by something when loaded.
And probably a bunch of other abuse loads.
RE: Maximum Load for a custom steel sawhorse
Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask
RE: Maximum Load for a custom steel sawhorse
Does OSHA or your insurance carrier have any requirements for said sawhorse?
The reason for this that we came under fire for using site built pipe stands and jacks. We were not allowed to test and use we had to get store bought ons. The ones we bought we not nearly as robust or steady as ours but the had a little stamp on the support column with all the vitals.
We did have numerous sawhorses built on the same pattern with angle iron for legs on the larger and pipe legs on the smaller. The only difference is we have shoes on the legs to help in moving them across floors.
RE: Maximum Load for a custom steel sawhorse
There are days when I wake up feeling like the dumbest man on the planet, then there are days when I confirm it.
RE: Maximum Load for a custom steel sawhorse
As long as the load is applied across the whole top surface, I'd say with a quick look it would safely hold 20,000lbs. This is a been there done that quess too. Are the welds good?
It will be interesting what you all calculate the load to be.
RE: Maximum Load for a custom steel sawhorse
That said, the standard Euler solution will likely overestimate the buckling capability. That solution is for long columns and stable cross sections. You probably have a short/intermediate column and definitely have an unstable cross-section (angle). As such, you should calculate the crippling strength of the cross section and use that in combination with a Johnson-Euler solution. That is the approach using in the aircraft industry since the cross sections are often unstable (L, C, I, T).
Brian
www.espcomposites.com