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Bus Discussion => Bus Topics ( click here for quick start! ) => Topic started by: zubzub on March 03, 2012, 05:43:16 PM

Title: How thick does 3X3 HSS tube need to be if a 500 lbs is hung in the center?
Post by: zubzub on March 03, 2012, 05:43:16 PM
How thick does  3"X3" wall of HSS tube need to be if a 500 lbs is hung in the center of an 11 foot span? Or is this unreasonable?  Esthetics/ fit  are dictating the 3x3, but if needs be I could go larger HSS or change over to I beam, but for various reasons would prefer not to.
I know we have some engineering folk around here, would really appreciate the input.  Thanks,  Patrick.
p.s. I tried searching the web but could not find a site called "Span Calculations for Dummies.
Title: Re: How thick does 3X3 HSS tube need to be if a 500 lbs is hung in the center?
Post by: bobofthenorth on March 03, 2012, 06:29:30 PM
No way I'd build this out of square tubing.  Way too heavy to accomplish what you want to, if its even possible.  If you use square tubing the weight of the tubing that you need to support could easily exceed the load you intend to support.  I'd build me a truss of some kind.  Maybe a injunneeer will chime in to do the drawing.  I could take a WAG at it but there'd be no elegance to how I'd arrive at a drawing.  I'm thinking something like 1" x 1/8 wall tubing skinned with maybe 12 gauge - 3 inches might be deep enough - need an injunneeere for that calculation.
Title: Re: How thick does 3X3 HSS tube need to be if a 500 lbs is hung in the center?
Post by: luvrbus on March 03, 2012, 07:05:48 PM
I have 3X3X10x1/4 square tubing spreader and have put a lot more than 500 lbs in the center and never bent it yet but if you are worried about it weld a 1in x 1/2 in bar 3 ft in each direction from the center fwiw I use a spreader made of 2x2x1/4 angle iron to left 3000#+ engines   

good luck
Title: Re: How thick does 3X3 HSS tube need to be if a 500 lbs is hung in the center?
Post by: Nusa on March 04, 2012, 01:21:46 AM
You might find this interesting:

http://www.steeltubeinstitute.org/pdf/brochures/beam_load_table_bro.pdf (http://www.steeltubeinstitute.org/pdf/brochures/beam_load_table_bro.pdf)
Title: Re: How thick does 3X3 HSS tube need to be if a 500 lbs is hung in the center?
Post by: zubzub on March 04, 2012, 08:58:49 AM
Thanks Clifford, that is kind of all I really need, though an actual table I could read would be nice.
Nusa, I had already found that table, and while some may be able to wade through the math quickly, I'm pretty sure I would be a few hours at least before I got to where I could work out the load of a given span.
Title: Re: How thick does 3X3 HSS tube need to be if a 500 lbs is hung in the center?
Post by: dvrasor on March 08, 2012, 08:35:38 AM
 
3x3x.250 is plenty strong for 500#
500#= two fat girls no problem!
All kidding aside you will be fine
with 3x3x.250                         

Dave Rasor-4104
Title: Re: How thick does 3X3 HSS tube need to be if a 500 lbs is hung in the center?
Post by: Uglydog56 on March 08, 2012, 09:25:46 AM
I can't believe it.  My Thomas J. Glover Pocket Ref does not have this information.  There is no Santa Claus!

From what I could decipher on the physics forums, that beam should be good mathematically to 1500lbs.  My intuitive non-calculatory brain thinks that beam thickness is probably excessive, but you know the first rule of overkill - you can never have too much overkill.
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