Working Load Limit Question

Topic 23184 | Page 3

Page 3 of 3 Previous Page Go To Page:
Grumpy Old Man's Comment
member avatar

We were taught to do the calculations like this. 1/2 weight of coil / WLL of chain = number of chains. 17250(34500/2) / 11300(wll) = 1.52 = 2. We only carry 1/2" and that coil requires 4 of them (WLL 4700). To me 7 seems excessive.

Given the way the question is worded, that was my answer as well, and as I said, I got the rest of them correct as well. The only way I saw that that made sense is if the chain was connected to the same side of the trailer, which would cut the WLL in half. But even then I would think it would be 8, not 7.

Grumpy Old Man's Comment
member avatar

Ok grumpy I’m going to try to help here with explaining their math. It appears in the example they have left a lot of details out of the question. Also don’t kick yourself too hard over this.

In the example it’s asking how many 1/2” grade 70 chains are needed to secure a 34500 lbs load keeping WLL to 50% of rating. Just to keep it simple we know 1/2” grade 70 has a WLL of 11,300 lbs. 34500/11300=3.05 if you stop and round to 4 here the chains are at just over 75% of their WLL in a ideal world. So we multiply the 3.05*2 to get 6.10 and round to 7 for again in a perfect world using 44% of the WLL on the chains. All the other variables mentioned by others are definitely something to be remembered but the test wanted the simplest answer possible.

Are you saying I should only rely on 50% of the chain's actual WLL?

As in, each chain which has a WLL of 11,500 should be treated as if it will only secure 5,650 lbs?

Brad C.'s Comment
member avatar

Oklahoma DOT requires a four point tie down on vehicles towed on a flatbed wrecker. Common practice is to use either 4 grade 70 chains with a 3700lb WLL or 4 2” wheel straps with a 3500lb WLL. Not a single vehicle I towed came close to a 14000 gvwr let alone actually weighing that much. So seven chains rated at 11,300 for a 34,500 coil doesn’t sound out of place to me. Just an observation based on my past experience as a non-CDL tow driver though.

CDL:

Commercial Driver's License (CDL)

A CDL is required to drive any of the following vehicles:

  • Any combination of vehicles with a gross combined weight rating (GCWR) of 26,001 or more pounds, providing the gross vehicle weight rating (GVWR) of the vehicle being towed is in excess of 10,000 pounds.
  • Any single vehicle with a GVWR of 26,001 or more pounds, or any such vehicle towing another not in excess of 10,000 pounds.
  • Any vehicle, regardless of size, designed to transport 16 or more persons, including the driver.
  • Any vehicle required by federal regulations to be placarded while transporting hazardous materials.

DOT:

Department Of Transportation

A department of the federal executive branch responsible for the national highways and for railroad and airline safety. It also manages Amtrak, the national railroad system, and the Coast Guard.

State and Federal DOT Officers are responsible for commercial vehicle enforcement. "The truck police" you could call them.

GVWR:

Gross Vehicle Weight Rating

GVWR is the maximum operating weight of a vehicle as specified by the manufacturer, minus any trailers.

Brad C.'s Comment
member avatar

double-quotes-start.png

Ok grumpy I’m going to try to help here with explaining their math. It appears in the example they have left a lot of details out of the question. Also don’t kick yourself too hard over this.

In the example it’s asking how many 1/2” grade 70 chains are needed to secure a 34500 lbs load keeping WLL to 50% of rating. Just to keep it simple we know 1/2” grade 70 has a WLL of 11,300 lbs. 34500/11300=3.05 if you stop and round to 4 here the chains are at just over 75% of their WLL in a ideal world. So we multiply the 3.05*2 to get 6.10 and round to 7 for again in a perfect world using 44% of the WLL on the chains. All the other variables mentioned by others are definitely something to be remembered but the test wanted the simplest answer possible.

double-quotes-end.png

Are you saying I should only rely on 50% of the chain's actual WLL?

As in, each chain which has a WLL of 11,500 should be treated as if it will only secure 5,650 lbs?

That seems to be the way the question is worded. Even if done so in a trick question sort of way.

Grumpy Old Man's Comment
member avatar

double-quotes-start.png

double-quotes-start.png

double-quotes-start.png

Ok grumpy I’m going to try to help here with explaining their math. It appears in the example they have left a lot of details out of the question. Also don’t kick yourself too hard over this.

In the example it’s asking how many 1/2” grade 70 chains are needed to secure a 34500 lbs load keeping WLL to 50% of rating. Just to keep it simple we know 1/2” grade 70 has a WLL of 11,300 lbs. 34500/11300=3.05 if you stop and round to 4 here the chains are at just over 75% of their WLL in a ideal world. So we multiply the 3.05*2 to get 6.10 and round to 7 for again in a perfect world using 44% of the WLL on the chains. All the other variables mentioned by others are definitely something to be remembered but the test wanted the simplest answer possible.

double-quotes-end.png

double-quotes-end.png

Are you saying I should only rely on 50% of the chain's actual WLL?

As in, each chain which has a WLL of 11,500 should be treated as if it will only secure 5,650 lbs?

double-quotes-end.png

That seems to be the way the question is worded. Even if done so in a trick question sort of way.

Except that all the other questions did not. It was strictly the aggregate of all chains WLL to secure at least 50% of the load's weight in all the other questions. I have searched the NY handbook, the Federal handbook, and none reference the multiply by two shown on that single question. I thought when I got the question on review, it would explain it, but it only shows the formula, no explanation

Brad C.'s Comment
member avatar

Haven’t made my way to the ny coils material yet so I don’t have the foggiest of ideas what the requirements are. Comparing the math in the question to my experience in the towing industry in the state of OK is why it makes sense to me. Although, I imagine there are major differences between hauling coils and hauling a vehicle on a flatbed wrecker. But the question does seem to want you to calculate the number of chains based on half the WLL rating. Just out of curiosity are you familiar with how securement devices (chains, straps, cable, etc.) are rated?

OWI:

Operating While Intoxicated

Grumpy Old Man's Comment
member avatar

Haven’t made my way to the ny coils material yet so I don’t have the foggiest of ideas what the requirements are. Comparing the math in the question to my experience in the towing industry in the state of OK is why it makes sense to me. Although, I imagine there are major differences between hauling coils and hauling a vehicle on a flatbed wrecker. But the question does seem to want you to calculate the number of chains based on half the WLL rating. Just out of curiosity are you familiar with how securement devices (chains, straps, cable, etc.) are rated?

Yes, they provide a chart showing the WLL of rope, chains, straps, and wire rope (cable).

OWI:

Operating While Intoxicated

Page 3 of 3 Previous Page Go To Page:

New Reply:

New! Check out our help videos for a better understanding of our forum features

Bold
Italic
Underline
Quote
Photo
Link
Smiley
Links On TruckingTruth


example: TruckingTruth Homepage



example: https://www.truckingtruth.com
Submit
Cancel
Upload New Photo
Please enter a caption of one sentence or less:

Click on any of the buttons below to insert a link to that section of TruckingTruth:

Getting Started In Trucking High Road Training Program Company-Sponsored Training Programs Apply For Company-Sponsored Training Truck Driver's Career Guide Choosing A School Choosing A Company Truck Driving Schools Truck Driving Jobs Apply For Truck Driving Jobs DOT Physical Drug Testing Items To Pack Pre-Hire Letters CDL Practice Tests Trucking Company Reviews Brett's Book Leasing A Truck Pre-Trip Inspection Learn The Logbook Rules Sleep Apnea
Done
Done

0 characters so far - 5,500 maximum allowed.
Submit Preview

Preview:

Submit
Cancel

Join Us!

We have an awesome set of tools that will help you understand the trucking industry and prepare for a great start to your trucking career. Not only that, but everything we offer here at TruckingTruth is 100% free - no strings attached! Sign up now and get instant access to our member's section:
High Road Training Program Logo
  • The High Road Training Program
  • The High Road Article Series
  • The Friendliest Trucker's Forum Ever!
  • Email Updates When New Articles Are Posted

Apply For Paid CDL Training Through TruckingTruth

Did you know you can fill out one quick form here on TruckingTruth and apply to several companies at once for paid CDL training? Seriously! The application only takes one minute. You will speak with recruiters today. There is no obligation whatsoever. Learn more and apply here:

Apply For Paid CDL Training

About Us

TruckingTruth was founded by Brett Aquila (that's me!), a 15 year truck driving veteran, in January 2007. After 15 years on the road I wanted to help people understand the trucking industry and everything that came with the career and lifestyle of an over the road trucker. We'll help you make the right choices and prepare for a great start to your trucking career.

Read More

Becoming A Truck Driver

Becoming A Truck Driver is a dream we've all pondered at some point in our lives. We've all wondered if the adventure and challenges of life on the open road would suit us better than the ordinary day to day lives we've always known. At TruckingTruth we'll help you decide if trucking is right for you and help you get your career off to a great start.

Learn More