0.8 g securement

Regulations aside, there must be some guidelines that one can use to determine how many Gs are produced in a stop over a given distance from a given speed & given weight?

 

This 330D should weigh in at roughly 80k according to Ritchie Brothers. So this is how I secure them. My 1/2" chain is not very long so those are used on the corners and then 3/8" over the frame. Now this does not count the chains over the boom section. And FYI, anything used to prevent articulation such as chains over the boom does not count towards your aggregate WLL. With this configuration I have 46,200 lbs of WLL on an 80k machine. Yep I like to overdo it a little. It tends to keep them from looking closer if you have more than enough chains. I also overdo it because Ritchie Brothers is wrong most of the time on their weights.


The rule for the breaking strength of a piece of securement is 3x the WLL so a 9900 lb 1/2" chain/binder would have a breaking strength of 29,700 pounds and a 6600 lb 3/8" chain would be 19,800 pounds. I don't even carry any dog tie out chain. Now with how I have this secured, you could take the trailer and flip it over with a crane and shake it and the excavator will not come off the trailer.

In this example I have 2 each 3/8" indirect tiedowns pulling back and 2 each 1/2" direct pulling back. If I figure the breaking limit on half the wll on the 1/2" chain and full wll on 3/8" chain then I have 69,300 pounds of breaking strength pulling backwards. This does not include the pounds of resistance from the other chains pulling down on the excavator.

Now if I were to use the full wll of the 1/2" chain to calculate the breaking strength then I would have 99,000 pounds of breaking strength pulling back on the excavator. I don't think this sucker is gonna budge.

Calculating the G force is just too much math and it hurts. There are way too many variables involved in the calculations. Basically if you hit a bridge and it moves, you did it wrong.

 

G force is simply weight, .8 g is 80% of an objects weight while not moving. gg force above 1.0 is the result of an object in motion. The rule about .8 g securement preventing forward motion takes into consideration of the friction of the load sitting on the deck. That friction varies according to the freight and deck surface. There are charts that give you the specific friction rates for different materials. That is why as long as you cover 50% of the loads weight dot doesn't bother you, it would be a lot of work to prove you don't comply, and almost every scenario I tried did comply

 

I am willing to bet when the FMCSA engineers & lawyers sat in their smoke filled rooms & made these rules, they knew there would be confusion & misunderstanding. Maybe they figured when the driver is in doubt what the law is, he will add more chain to cover HIS arse.. There is no "one size fits all" in this business. Different experience levels, different trailers & different loads force the Gov. to cover THEIR arse with rules like this. Same with the HOS rules. On an excavator or dozer I think the simplest way to make the DOT happy might be to just put 2 short chains &2 binders on each corner. Sure glad I'm on my way out..............

 

Read it here in this one, https://www.fmcsa.dot.gov/regulations/cargo-securement/cargo-securement-rules

Under the section that says;
Minimum Working Load Limit for Cargo Securement Devices and Systems.

"The working load limit for each tiedown that goes from an anchor point on the vehicle, through, over or around the cargo and then attaches to another anchor point on vehicle.

 

They contradict themselves many times. I go by whatever has the newest date of publication because that will supersede older rulings.