Posted: 12/25/2005 10:19:23 PM EDT
| Where would I find the colapse rating on mild steel square tubing. |
+1. There's a big difference in how the load is taken by the tube. Axially? Laterally? Try here if you have the data. |
It says right in the description.....
 Dolly will be ok.  |
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Structural steel is not load/span rated like lumber. There is a mathematical equation used to find "moment of inertia". Needless to say you don't want to find moment of inertia through trial and error. Box tubing is fairly rigid stuff even in light gauge. Box tubing also is avaiable in rectangular configuration for reduced deflection. What are you building and how long are the spans, how much load? |
Wont it need to be upgraded and reinforced for use with a horse? |
I will run a couple numbers and get back with you shortly. In the meantime, if you can tell us the span, we can estimate the load rating. |
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The 2.0x6.0x0.188" tube has a shear capacity of about 5,400 lbs, and a moment capacity of about 85,000 ft-lbs. With the maximum load of 5,400 lbs in the center of the span, the maximum span is 15.7'. The 2.0x6.0x0.125" tube has a shear capacity of about 3,600 lbs, and a moment capacity of about 59,000 ft-lbs. With the maximum load of 3,600 lbs in the center of the span, the maximum span is 16.4'. These figures are the maximum condition, and do not account for buckling of the beams, bi-axial bending, bending-axial interaction or other effects. |
It's a start. You have to define the supports and load too. What kind of supports, how many, and how far away are they? What kind of load, and where is it? Will the load be static, just hanging there, or will it be swinging and moving around? Are there any impacts involved? Will the supports be moving around? |
WTF Cav? 
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Fill them with concrete and cap the ends if you're worried about it...  You're just worried about them squashing ? Correct ? You want to run wires across a parking lot or driveway ? There are better solutions to that... I've seen special mats with provisions for wires, tubing, etc... I think it was McMaster Carr or Grainger.... Will edit later after work. |
Dragracer_Art's got the right idea! |
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Use DzlBenz' 5000 lbf per tire, assume a tire is 10 inches wide (WTF, I have no idea how wide the truck tire is, but it doesn't matter as you will see) - As the tire creeps up the ramp, it will load one web of the beam before the other, so the compression stress in that web is 5000/(10*0.188) = 2.7 ksi. If that beam is A36 or similar mild steel, and I needed an answer right now and didn't have time to calculate the compression buckling allowable because there are terrorists that needed to be killed right now, I would drive the truck over without a second thought. If the ramps are an inverted U-channel, the stress is siginificantly higher. If the ramps are flat bottom boards, the area served is larger than the tire footprint and the actual stress is lower. Since this is a beam on an elastic foundation, unless there is something unusual in the configuration, that will also reduce the effective stress even further. If I had a manual handy, I would calculate the buckling stress, but I don't, so I ain't. Even with a factor of safety of 5, the stress is just over 13 ksi. Unless these tubes are manufactured from peanut butter, they will easily support 5000 pounds at a tire. You are more likely to have a stability problem with the tubes rolling over due to a lack of lateral restraint. |
You're *probably* not at work this week, (neither am I  ) which means you can do this stuff at home.Therefore, 1GR, I'd say this is about right. Merlin |