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DMiller 
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Joined: 14 Sep 2009
Location: Hermann, Mo
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 Topic: May have some Issues brewing
Posted: 05 Oct 2024 at 5:58pm |
On truck I daily run. Is a Heavy monster at 35,000 Empty, then is a Bigger issue, sat down with tape measure, and did the Old Basis Bridge Formula that seemingly NO ONE ever bothers with anymore. Used to hand build Dump Pup Trailers for behind Tandem Dump trucks and had to alter several that could not meet Bridge Law. Current truck and trailer measure out well above 52' long, HOWEVER, under Bridge Rues must measure from Front driver to rearmost trailer, can ONLY achieve 34 feet there, shuts off the Max GVW to 64500 against license weight of 80,000, close to 8 ton I generally carry as TOO Much.
MoDOT has begun to stretch the tapes recently.
Edited by DMiller - 05 Oct 2024 at 5:59pm
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Lars(wi)
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Posted: 05 Oct 2024 at 8:44pm |
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34 feet from the axle of the forward driver, to the axle of rearmost of the trailer?
Are you allowed to have a tag axle in front of the drives?
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I tried to follow the science, but it was not there. I then followed the money, and that’s where I found the science.
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DMiller
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Posted: 06 Oct 2024 at 4:35am |
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Truck has not the WB to do that, what most do is add weight dispersal axles on the trailer frame to reduce axle to axle weights and reduce the signature as required by the Bridge Formula, which BTW is out of date to the 1950s.
This trailer is considered a Quarter Frame, was intended for use in building demolition inside cities where a Commercial Zone standard eliminated the Formula as to roads destructions. In STL KC or Columbia MO can exceed axle weights by either adding axles or buying a permit, on the Interstate system is not allowed.
Edited by DMiller - 06 Oct 2024 at 1:21pm
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truckerfarmer
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Posted: 06 Oct 2024 at 8:22am |
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Add 12,000 for your steer axle. That will get you to 76,500, so just short of 80,000.
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Looking at the past to see the future.
'53 WD, '53 WD45, WD snap coupler field cultivator, #53 plow,'53 HD5B dozer
Duct tape.... Can't fix stupidity. But will muffle the sound of it!
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DMiller
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Posted: 06 Oct 2024 at 1:21pm |
Incorrect, Bridge Formula once get to the Drives and Trailer four axles that is ALL allowed. Bridged Weight.
Actually took a class on this nearly as confusing as it looks BS Formula, State Brown shirts noted the Drop in GVW once lose trailer length, we all tried to add the steer but the number is Total GVW reduced due to short length.
Edited by DMiller - 06 Oct 2024 at 1:24pm
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Coke-in-MN
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Posted: 06 Oct 2024 at 4:25pm |
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When I was pulling tank trailers and the 80,000 GVW - couple tickets for overweight .
Found the front axle was light by what tickets were for . Never over the 80 but off on the bridge weight .
Finally brought scale weight to shop foreman to have him move trailer pin to put weight on front axle - moaned about that would put some other trucks to heavy if they pulled the same trailer . It seems their answer was pay the fines , not do the work .
90% of the time I pulled the same trailer over 3 years with same power unit day cab, and they were worried some owner operator with a sleeper might use the trailer .
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Faith isn't a jump in the dark. It is a walk in the light. Faith is not guessing; it is knowing something.
"Challenges are what make life interesting; overcoming them is what makes life meaningful."
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Coke-in-MN
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Posted: 06 Oct 2024 at 4:28pm |
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One of the gravel pits I pulled out when I hauled rock , had a IH dump truck in shop most of the time , Asked about it - said it was so heavy it could not hold but 1/2 load their other trucks carried - so they used it as a PARADE TRUCK - cleaned and polished but not worked .
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Faith isn't a jump in the dark. It is a walk in the light. Faith is not guessing; it is knowing something.
"Challenges are what make life interesting; overcoming them is what makes life meaningful."
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truckerfarmer
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Posted: 06 Oct 2024 at 10:10pm |
 DMiller wrote:
Incorrect, Bridge Formula once get to the Drives and Trailer four axles that is ALL allowed. Bridged Weight.
Actually took a class on this nearly as confusing as it looks BS Formula, State Brown shirts noted the Drop in GVW once lose trailer length, we all tried to add the steer but the number is Total GVW reduced due to short length.
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Better look again. Your own charts prove my statement. GVW includes all axles. Using your theory of only using the trailer and drive axles for a GVW of 80,000, you would have to be able to carry 40,000 at each end. that would require a 10' spread at each end.
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Looking at the past to see the future.
'53 WD, '53 WD45, WD snap coupler field cultivator, #53 plow,'53 HD5B dozer
Duct tape.... Can't fix stupidity. But will muffle the sound of it!
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truckerfarmer
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Joined: 26 Jan 2013
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Posted: 06 Oct 2024 at 10:21pm |
  I've played the bridge formula game. These are a couple of the rigs I've run. The double belly dump was legal for 142,000. The sidedump as I recall was legal for 94.500.
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Looking at the past to see the future.
'53 WD, '53 WD45, WD snap coupler field cultivator, #53 plow,'53 HD5B dozer
Duct tape.... Can't fix stupidity. But will muffle the sound of it!
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DMiller
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Location: Hermann, Mo
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Posted: 07 Oct 2024 at 3:16am |
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Take it up with DOT, they were the ones that onstructed the reduced level as the Four axle weight reduced to a lesser value. Use the math formula and the steer acle is removed from the equation. Still no room tanks to first driver to install a Lift axle, too short of wb, that and being quarter frame is no position to install a trailer lift axle.
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DMiller
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Posted: 07 Oct 2024 at 3:21am |
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DaveKamp
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Posted: 09 Oct 2024 at 2:34am |
Miller's predicament isn't a federal highway bridge limitation, it's Missouri.
Due to my line of work, I get asked about this kind of thing very often, and there's generally two vital circumstances that influence a state's bridge law...
The first is how the civil structures were originally designed and built, and the second is how tight the highway road radiuses were generally laid out.
The latter has a very heavy determination on the former, because navigating a tight apex with a long wheelbase results in the truck either spanning across the opposing lane (in a left hand curve) or extending over the shoulder or into right-lane traffic (in a right hand curve). When passing through a tunnel, or under a viaduct, a long trailer risks striking overhead structures in those curves, and the only solution is to go to shorter-wheelbase trucks...
And that means that the loading of axle groups is inherently closer together, meaning a segment of bridge decking is subjected to much higher local load, than if the truck deck was 50ft longer.
Bridge law is all about concentration of loading. A 100ft long truck with a 50,000lb load concentrated in the middle divides the load into 25k loading at each end. At 100ft, the bridge's deck segments are short enough that the decking segments that the steer and drive just drove over you, will be clear of a span section before the trailer end makes it's way on... but if that is, instead, a heavy-built short trailer will be able to pack it's entire heavy weight... all tires... on the same segment of bridge... and that means there's room for another identical load following close.
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Ten Amendments, Ten Commandments, and one Golden Rule solve most every problem. Citrus hand-cleaner with Pumice does the rest.
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DMiller
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Posted: 09 Oct 2024 at 4:18am |
It IS a Federal Highways Admin Formula.
It has always been a Federal Formula, and problem. States as MO and the further East where roads were developed and expanded upon by repurposing old wagon and farm trails, most call the hill country roads Ridge Runners as follow ridge lines of hills. Bridges tended to be shorter and less well built as were built expecting to be used for a hundred years where have been. Load Limits, lots of other concerns and the FHWA Bridge Formula came about during the heyday of truck weights growth 1930s/40s. A semi in 1977 was typically licensed 73,280lbs, 80k did not happen until the 1980s as fuel consumption to move products became so prevalent, a typical dump truck in the 1960s carried 6-8 yards of materials where today is 16-24 yards. Axle Loading was as enforced where scales weighed Per Axle not per truck as do today.
Edited by DMiller - 09 Oct 2024 at 4:19am
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