Estimating weight of overhead cranes

Sigh, iggy that should have been verizon.net, not .com, sorry. So please send me an email that I can reply to at carl . ijames at the aforementioned. Thanks.

OK, so, to boil my question down to a simple sentence, it is as follows:

How to guess the weight of an overhead crane, given 1) Capacity and 2) span. I am not allowed to climb on it and measure thicknesses, etc.

This is a very practical question and if I can find an answer, I am sure that it will be helpful to make money.

I just realized that it is not as complicated as I thought.

For example, say, I can ask a question, "find the weight of an optimal I-Beam that would support a given weight and span a given distance".

Well, this is actually the most common engineering question. I am sure that there are helpful I-beam calculators that can give me suggestion for an I-beam, given weight, span and acceptable deflection.

If so, then, the weight of an I-beam crane is just that. For other cranes, such as double girder, box girder and so on, it will be slightly different, but similar and proportional.

I understand that a crane has components other than I-beams, such as end trucks, hoist, etc, but again it should be simply adding a percentage allowance to the I-beam calculation.

I will dig a little to get an answer.

i
Reply to
Carl Ijames
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Yes, technically, but that unit is far more refined and easy to use. It's also cheap compared to your other operating costs related to a semi and certainly any overweight fines.

Reply to
Pete C.

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The "optimal" weight that way I'd guess will be quite a long way under the actual sizing used for overhead lifting owing to safety factors and the like, as well as the steel quality (hence properties) used.

Load tables for beam design to meet building Code, etc., aren't going to be applicable. I _think_ there are likely similar for lifting but whether these are Codified anywhere other than ANSI Standards and/or OSHA guidelines that reference such and all I've never researched.

You can probably get some ballpark estimates this way but it'd be risky to rely on those for either rigging calculations or loading (especially the former, of course, the latter is just $$, not lives).

Reply to
dpb

Dan, the point is, this method lets me compare weights. If I know a weight of one comparable crane, even of different capacity and span, I can extrapolate.

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Reply to
Ignoramus14645

Reply to
Ignoramus14645

Reply to
Ignoramus14645

I think you would have a better estimate if you made your best guess as to the standard structural steel used in the beam and calculated from there. If I recall correctly cranes used to lift explosives had a larger safety f actor than cranes used for non explosive components.

Dan

Reply to
dcaster

Yep, you need to figure the weight in two ways, first (from reference materials) to estimate how many semi loads it will take to move what you bought, and second (from your air suspension) to load your semi without going overweight and getting fined.

Reply to
Pete C.

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Are they really 100% air-supported? I don't know they're not; just thought there would be a separate parallel mechanical support path as well...altho I guess it only changes the proportionality constant unless it's nonlinear. Which could still calibrate albeit not with single constant.

The grain trailers here nor the tractor aren't so don't have a comparison...

Reply to
dpb

Proportional enough that there are commercial load scale products for it. The RWLS stuff says it reads to 100# increments which isn't bad vs. the 20# increments of a typical CAT scale.

Reply to
Pete C.

That doesn't say anything about what the calibration curve actually looks like, though...can calibrate a very nonlinear response as noted above...

Reply to
dpb

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