So here's the rundown. I work for a machinery moving company and we

occasionally haul objects well in excess of 150 tons. We occasionally

get asked what our axle loads will be and just recently found out the

method we had been using isn't very accurate. There is software out

there that will do this but it's very expensive. So what I'm looking

for is if anyone can tell me how to do the following or at least point

me in the right direction as I've tried treating things as an assembly

of simple beams but the numbers just don't look right. We have access

to measure anything we need with the exception of weights which are

either measured previously or given from the manufacturer.

The basic assembly is we have a semi-tractor, it's weight, the lengths

between steer & 1st drive axle, 1st & 2nd drive, 2nd & 3rd drive

axles, and the fifth wheel position (adjustable) in relation to any of

those wheels.

Behind that is a dolly, with all wheel to wheel measurements, weight,

and wheel to kingpin & wheel to fifth wheel measurements. It has 4

axles.

Behind that is a trailer which we know the weight, kingpin to wheels,

and wheel to wheel dimensions.

On the trailer is a load, which is roughly a uniformly distributed

box. We know it's overall length and distance from center of gravity

to the kingpin, and consequently, the wheels.

Is there a simplified formula, or a process that I can go through to

determine this? I don't have any engineering background but I

understand some of the basic concepts. I tried figuring it out using a

simple beam uniformly loaded partially distributed but that didnt seem

right nor did it work out at all when i transfered that force to the

dolly calculations. Any help would be greatly appreciated!

- posted
14 years ago