Weight distribution, Forklifts in intermodal container 1

[dsmattman]

Working on loading small CAT forklifts etc into intermodal containers.
Four wheeled vehicle; weight 10K or less
Per wheel is 1’ x .84’= .84 sqft per wheel x 4 =3.36 total sqft
10k / 3.36 is 2976.20 lbs per sqft

my boss (not an engineer) tell me that I do not have this right. That the frame and axle of the CAT distributes the weight and the actually lbs per sqft is the total size (width times length) by weight and not the contact point (wheels). I need to hear if I'm right or him right? He used the idea that a arch can support a bridge up and strong due to the design and does most of the distribution of weight. Or that a 25 pound weight in your hand is supported by my entire arm and core not just my hand. I do not believe this relates BUT must be delicate when handling ones upper management.... PLEASE HELP,

Another question is if I stick two 2x6x8 under the wheels of this CAT how can I figure out how much weight I'm actually distributing, what is my new lbs per sqft. It isn't truly evenly distributed. In the end I believe I will be building a pallet that they can drive on to then secure.



random thought;;;

My railroad has a rule that says lading cannot be more than 300 lbs per sqft. The AAR (association of america railroads) only has a rule about 25,000 lbs per 10 linear feet. Other class one railroads restrict it down to 2500 lbs per linear foot, and one has told me that their rule of thumb is no more than 625 lbs per sqft. I cannot find any data or facts to support any thing but the 25,000 per 10 linear feet due to floor rating on most containers. No one in my company can even tell me why or where the 300 lbs per square foot came from. We ship millions of containers today that have a larger foot print than 300 lbs per square foot without a issue.

 

[jittles]

Both loadings are valid checks, but you check them against different capacities.

It's a local check at the wheel, but more of a general global check over the footprint. The capacity of a whole container might be 10000 lb, but that doesn't mean that 10000 lb concentrated in a small area couldn't fail the floor of the container locally.

For example, ASCE 7 live loading for things like a parking structure have a relatively low uniform load (global check) but also a concentrated load applied over a small area (local check).

 

[chicopee]

If the 10,000lbs rating is the tare weight then much of that weight would be from the counterweight and I suspect most of it would be borne by the rear axle. Get the manufacturer's data to determined the center of gravity when the forklift is not carrying anything and when it is lifting to its capacity. As far as the pressure on the ground the tire foot print would resemble more that of an elliptical form than that of a rectangular form. For what it's worth, a forktruck is considered to have a three point axle unlike other machinery and are more prone to tip sideways.