Bridge Load Limit

[yanmars]

Could you have him carry a lighter/partial load or a smaller truck?

 

[BrokenTrack]

The real problem is with the I beams used. There was quite a bit of talk about the other components of the bridge, but it does not really matter. They are sitting on (4) 10 inch I beams only 3/8 thick. The thickness is not so much of a concern, as much as their depth. 10 inches is not that strong.

But the real, real, real issue is: you have a trucker that will not cross it, and I doubt that would change if you had built it out of 20 inch deep I beams. So, you really need a new truck driver.

Or, have him dump on this side of the bridge, and use your tractor and bucket to ferry it over the bridge, as long as the distance is not that far.

 

[Redlands Okie]

Would only have to dump some of it. Be easier and less costly to just haul smaller loads I suspect. Or find another supplier.

 

[Deere Dude]

Depending on how far away the quarry is I would consider a 5 yd truck. Smaller truck and smaller load multiple times.

 

[Egon]

For your situation either make a bypass on the creek bed or get some stamped plans.

The bridge looks good at first glance and may be quite strong but looking more closely every aspect of it starting with the footings would negate getting proper approval from any authority. I would doubt a professional would even try to determine an acceptable load for the bridge. Relying Only on beam tables for design strength is a far cry from how the bridge design works.

 

[Egon]

For your situation either make a bypass on the creek bed or get some stamped plans.

The bridge looks good at first glance and may be quite strong but looking more closely every aspect of it starting with the footings would negate getting proper approval from any authority. I would doubt a professional would even try to determine an acceptable load for the bridge. Relying Only on beam tables for design strength is a far cry from how bridge design works.

 

[fried1765]

For your situation either make a bypass on the creek bed or get some stamped plans.

The bridge looks good at first glance and may be quite strong but looking more closely every aspect of it starting with the footings would negate getting proper approval from any authority. I would doubt a professional would even try to determine an acceptable load for the bridge. Relying Only on beam tables for design strength is a far cry from how the bridge design works.

^^^^^^EXACTLY why I stated ..ABSOLUTELY WOULD NOT...in my post #15.
I asked one of my old Civil engineering college roommates about this too. He is a retired state DOT Registered Professional Engineer (still does bridge const. consulting).
He said: Not only NO, but HE11 no!

 

[BrokenTrack]

^^^^^^EXACTLY why I stated ..ABSOLUTELY WOULD NOT...in my post #15.
I asked one of my old Civil engineering college roommates about this too. He is a retired state DOT Registered Professional Engineer (still does bridge const. consulting).
He said: Not only NO, but HE11 no!

But to be fair, I would expect that. They design bridges for a safety factor of two or more.

He would cringe if he saw some of the bridges we have hauled 100,000 pound loads of logs over, but as I said in my first post, it is not often you have a bridge so long that the whole truck is on the bridge at once.

Here is a fun fact though: Maine had the first weight limits for trucks.

 

[mwb]

Google a software tool called "Beam Boy". This is a very simple to use engineering tool that will calculate stress and deflection for you. Download BeamBoy 2.

Garbage in = garbage out so you need to be careful of your assumptions. This SW has selectable beams (just pick the one you are using) or you can spec out your own (more complicated).

 

[Egon]

As has been mentioned there are quite a few more factors involved than a set tables.

 

[fried1765]

But to be fair, I would expect that. They design bridges for a safety factor of two or more.

He would cringe if he saw some of the bridges we have hauled 100,000 pound loads of logs over, but as I said in my first post, it is not often you have a bridge so long that the whole truck is on the bridge at once.

Here is a fun fact though: Maine had the first weight limits for trucks.

My Civil engineering RPE former roommate lives in Winthrop, Me. and is retired from the Maine DOT.
After nearly 60 years, we still talk by phone.
A really great "Mainiac" guy talking with his "Masshole" classmate.

 

[BrokenTrack]

My Civil engineering RPE former roommate lives in Winthrop, Me. and is retired from the Maine DOT.
After nearly 60 years, we still talk by phone.
A really great "Mainiac" guy talking with his "Masshole" classmate.

He probably knows my ex-father-in-law, he worked for the MeDOT all his life as a surveyor. He is long since retired, and I lost track of him when I got divorced from his daughter.

He was telling me, back in the 1980's, he had to scale Mt Katadin because the State wanted to survey a road to the top. He said it was stupid because anyone knows, when Governor Baxter gave the state the land for that park, it specifically states, "No Motor Vehicles" so they would never build a road to the top. Still, somewhere, they have a map of a road on how to get to the top.

But he was interesting. When I fist met him...the very first time, he did his research on me and said, "Oh yes, the BrokenTrack family, you sold 100,000 yards of gravel to the MeDOT in 1969, at 10 cents a cubic yard, with you grandfather loading the gravel with his tractor..." It was all true. I have since tried to find that report so I could see what the Maine Geological Society had for information on the pit, but it seems no one but him could find the report.

 

[fried1765]

He probably knows my ex-father-in-law, he worked for the MeDOT all his life as a surveyor. He is long since retired, and I lost track of him when I got divorced from his daughter.

He was telling me, back in the 1980's, he had to scale Mt Katadin because the State wanted to survey a road to the top. He said it was stupid because anyone knows, when Governor Baxter gave the state the land for that park, it specifically states, "No Motor Vehicles" so they would never build a road to the top. Still, somewhere, they have a map of a road on how to get to the top.

But he was interesting. When I fist met him...the very first time, he did his research on me and said, "Oh yes, the BrokenTrack family, you sold 100,000 yards of gravel to the MeDOT in 1969, at 10 cents a cubic yard, with you grandfather loading the gravel with his tractor..." It was all true. I have since tried to find that report so I could see what the Maine Geological Society had for information on the pit, but it seems no one but him could find the report.

I would certainly assume that he would know your ex-father-in-law
I believe that Brian may have actually started with ME DOT as a surveyor in 1961.

 

[Jw5875]

Well Gents,
A fellow TBN'r helped me with the information I needed.
Many Many "Thanks" to him and his team.

MY decision is to reduce loads to a tandem axle truck to
keep all parties agreeable to the suggested weight capacity of
the bridge.



JW5875

 

[Redlands Okie]

Nice of you to post information on the final result. Many do not

 

[quicksandfarmer]

 

[crazyal]

What's funny is if you've ever seen some of the 'temporary logging bridges' in this country that fully loaded trucks cross yours looks like the Golden gate. But, at the end f the day, it's the driver who pays the price. Saying "but he said it was good" doesn't cut it with the boss or the insurance company. Glad you've found a compromise everyone can live with.

 

[fried1765]

What's funny is if you've ever seen some of the 'temporary logging bridges' in this country that fully loaded trucks cross yours looks like the Golden gate. But, at the end f the day, it's the driver who pays the price. Saying "but he said it was good" doesn't cut it with the boss or the insurance company. Glad you've found a compromise everyone can live with.

A friend of mine in Canada, was driving a log truck over just such a bridge, and the bridge failed.
Took nearly 5 years, and lots of attorney (barrister there) dollars to finalize the case.

 

[ArlyA]

View attachment 653298

Gee, Calvin and Hobbes is an old favorite of ours :thumbsup:

 

[3Ts]

When I was a teenager in Ohio, the historical covered bridges were open for vehicle traffic, but normally had a weight limit of 5 tons for them. One day there was a picture in the paper of a fully loaded dump truck that had fallen thru the floor of the covered bridge. I don't remember what the outcome of that was but I can guess.