Bridge law

[CanaryBoss]

Does anybody really understand bridge law? I’ve read the info but just can’t get it. With twin steer axles and tandems I. The rear(4 axles total) what are my limits? From what I see I have 21’ from front axle to rear tandems. What is my total limit?

 

[Merle Nelson]

Numbers and equipment....sounds like you want Lumberjack.

 

[Reach]

It appears to me that in Florida, if you have 21’ from the center of your forward-most axle to the center of the rear-most axle, your total allowable weight would be 56,000 lbs. however, you also have to calculate each pair of axles to be sure you do not exceed the allowable weight per pair.

I found that information with a fairly useful chart and examples; I’m not sure if it’s what you used but it may be helpful. https://ops.fhwa.dot.gov/freight/publications/brdg_frm_wghts/index.htm#table

 

[CanaryBoss]

Maybe I’m not reading this correctly but it does not seem to be compliant and it certainly does not seem to have any available payload that could be added.

 

[Reach]

I would agree, it does not seem to be compliant based on what the chart says. The drawing you just posted shows the truck at 23’ from front to rear most axle, which allows you a maximum gross weight of 57,500. What I am not sure of however is if the twin steer axles make any difference. I would not think they should, but it may be worth looking into.

Here in PA, we have a chain of very knowledgeable notaries called Wiggins Auto Tags; if you have any of those or something similar, perhaps give them a call and maybe they can confirm once and for all whether or not this truck is compliant. Or maybe the company you use for your DOT compliance, if you have one?

 

[CanaryBoss]

I appreciate the input. From what the salesman said, it’s front center to rear center, so 24’. He says that makes me good for 61k lbs. the charts read different to me but he swears he spoke to Florida department of transportation. He also says that although they originally the bed as counterweight, they retested the truck today and say it is 100% stable without it. So, I’m at the max legal limit. Then I can’t haul a trailer or mats or anything. What the heck?

 

[Reach]

Well, hopefully the truck builder knows what he is talking about. Perhaps he will give you something in writing so that you can show it if you ever have a problem with DOT.

Truck cranes are usually very heavy and can’t haul a lot on the deck, but that’s ridiculous! You should certainly be able to haul at least a couple stacks of mats and pull a skid loader around behind you.

 

[TimBr]

@Lumberjack?

 

[climbhightree]

Unfortunately that is part of the problem with wanting a short truck...doesn't matter how many axles you have on the ground, your full weight is all on the bridge section (or in between supports) not spread out between spans/supports.

 

[climbhightree]

I appreciate the input. From what the salesman said, it’s front center to rear center, so 24’. He says that makes me good for 61k lbs. the charts read different to me but he swears he spoke to Florida department of transportation. He also says that although they originally the bed as counterweight, they retested the truck today and say it is 100% stable without it. So, I’m at the max legal limit. Then I can’t haul a trailer or mats or anything. What the heck?

Count your blessings...61k is almost 2,000 more than you could have in PA for a 24' truck.

Had to edit post forgot to add the axles.

 

[Steve Connally]

I relied on the builder to make sure I was compliant. I have to use the drop at all times to be compliant. I don't really understand how it works. I just went by what I was told and go across the scales pretty regularly. When I took delivery westminster helped me weigh the truck and put the appropriate PSI in the drop to equal out the weight. I run about 30psi on the drop and they tell me that makes me compliant. I have to admit it confuses the hell out of me.

 

[Lumberjack]

If you have to follow federal bridge law and an 80klb cap, a mec doesn't have much payload nor towing capacity... it's a math problem.

Also using a $300k+ crane as the primary means to move tree debris given the quantity of material the crane can get on the ground vs the limited amount of material it can move seems like a losing proposition.

24' outside bridge on 4 axles means on with bridge law you're allowed 58klb. State roads can be different, but that'd apply to interstates and other federal roads.

From the looks of your build sheet, the bare truck with the flatbed is overweight by 3klb, although they comically say it has a 13klb payload. You can't fit enough axles in 24' to bridge 79klb. 8 axles in 28' gets you there (minimum axle spacing is 4' for bridge law).

 

[CanaryBoss]

If you have to follow federal bridge law and an 80klb cap, a mec doesn't have much payload nor towing capacity... it's a math problem.

Also using a $300k+ crane as the primary means to move tree debris given the quantity of material the crane can get on the ground vs the limited amount of material it can move seems like a losing proposition.

24' outside bridge on 4 axles means on with bridge law you're allowed 58klb. State roads can be different, but that'd apply to interstates and other federal roads.

From the looks of your build sheet, the bare truck with the flatbed is overweight by 3klb, although they comically say it has a 13klb payload. You can't fit enough axles in 24' to bridge 79klb. 8 axles in 28' gets you there (minimum axle spacing is 4' for bridge law).

Thanks for the input. I agree about not hauling with the truck. I have decided to just support all of my crews with the truck as needed and sub when available. I got the same calculations but the builder swears it’s 61000.

 

[craneguy1]

Of course they do, they want that check! Same reason why they certified it without the bed; still sounds like it maybe too heavy for a bridgelaw state.

 

[Lumberjack]

It could be legal on FL roads but not federal roads like interstates.

Their beds typically have structural weights built into them, certifying it without the bed sounds like what craneguy is saying.

Good luck with the purchase.