Father's Bridge

You will build an heirloom,that will still be used when your great grandchildren ask their dad about it.

Glad I could help.

Good luck!

You should make a video of the entire process....that would be cool...or get someone who would like to make a video record...good for family gatherings..You could share some pics here, we love that kind of stuff....

That should work but it's close.

An 18 yard dump truck loaded with gravel will approach 80,000 pounds.

I like an arch design...

....or I guess you could buy some prefabricated bridge spans....

https://truenorthsteel.com/bridge/vehicular-bridges/

Hey look, design tool...

Fun for the whole family....

https://usbridge.com/

no doubt...

https://media.giphy.com/media/3ohuPhMYmK5iQIPHb2/giphy.gif

The reason I mentioned flat cars as a bridge was that I read where,after an earthquake,the engineers were looking for a quick way to replace bridges.

One of the young engineers suggested using flat cars for the spans.

After due consideration,they decided that it was a suitable replacement for the spans,an only needed the abutments to be rebuilt.

Just think about the stresses and shock loads a flat car has to survive for many years.

It would not be smart to design a bridge the same as a flat car,because they are

over built for this purpose,but if you can buy one for scrap price,why not?

Modern bridge designs are built for max economy of materials and labor and durability,strength.

Step right up and take a gander at our wide selection of premium used stock...

Just $23k ...+ additional shipping and handling charges may apply...

Seriously how am I going to move this? Let's see, where's the nearest railroad yard...weighs a little over 40k lbs+ a mere 89 ft long....? logistics...

Ah here we go with the wooden planking...70k lbs...just cut it in half and weld them together side by side...

Flat cars also come in 60ft lengths.

It doesn't matter how you do it,it is not going to be cheap.Perhaps culverts?

Not much information given.

Here is a link to an awesome flat car bridge:

https://www.redi-rock.com/build-design-road-bridge-railroad-car.htm

The abutments are the most important parts of a bridge,If they fail,the whole bridge fails.When blowing up an enemy bridge,they are taught to start with the abutments first.If you blow up the middle,there is a smaller gap to bridge.If you destroy the abutments,they must start all over.If using 2 or more flat cars,join them on an angle to transfer load to the ends.(Create an arch).

If you insist on doing it with timbers,use this image as a guide:

Or this one:

You could just lay a big pipe in the middle and fill it in with rock and gravel...

...or something like this....

https://bigearthsupply.com/product/12-24-rip-rap/

Culverts(pipes) are available in HDPE plastic of many large sizes to handle just about any load or size.Might be the best bet yet.

https://lcnme.com/currentnews/whitefield-culvert-project-complete-will-improve-fish-passage/

HDPE culvert pipe does seem to be the best way to go...

https://online.ogs.ny.gov/purchase/spg/pdfdocs/3770022719Cat_ISCO.pdf

Tyler

i think you could get some used i beams I've used 24" tall 8. " flange 5/8" thick beams for a similar project I would park three concrete trucks on that span ( exaggerated ) but those type of beams carry a lot there is an exact math to calculate their capacity ( look at a parking garage) but what you were referring to using a railroad body makes sense think how much wieght they can carry. I bought mine for a couple hundred each from a guy that Demos buildings and took them on a 50 ft flatbed easy . If your worried put 3 or 4 but loggers do this all the time and run 100,000 lbs all day , just find a local demolition company or steel scrap yard , new might be too expensive remember scrap is very cheap these days. Good luck buddy

You do not give anywhere near enough information for even an educated guess.
OK, you can assume maximum legal road limits for GVM (Gross Vehicle Mass) but where I am is 100% certainly going to different to where you are.
OK, you mention abutments, but how can they be designed if you don't know the beam required for the span?
What is the distance between the top of the bridge and whatever it is crossing? As "phoenix911" said ",... is it a ravine! ditch or is it a navigable waterway?" and I would add another road or a flowing creek/river/stream?
What is the clear distance required between the underside and whatever is underneath the bridge going to be?
Why 5 beams?
As "redfred" said "Hire a professional engineer"

This is very well worth the visit should any of you be in the area of North West PA!

There is not an abundance of information presented. How about some photos of the area to be spanned, what is the weight of the loaded trucks, also what are the earth conditions at the abutments for a start. Possibly a properly sized culvert would do the job?

A 50-foot-spanning bridge, to convey heavily loaded motor vehicles across it, is way more than just a casual ''back yard'' job.

Do it right, by starting with hiring a licensed structural engineering firm, and following their advice, before you hurt anybody...

As a Registered Civil Engineer, I have to regretably agree...

GA from me for an answer that's not too far off topic, imho...

I appreciate the humbled response...

I tend to come of strong to a point of offending the more weaker ‘professionals’ especially the academia types.

Thanks, I try to be a Sargent-Joe-Friday-type of Civil Engineer (i.e: Just the facts, (man), just the facts.)...

The OP seeems to have been lucky, so far, (improvising) certain bridge-type structures, but, operating suchly as a bridge designer is un-ethical, to say the least...

Luck is nice to have, while it lasts, but it never lasts ''forever''...

Phoenix911, it seems that GA's do not, in some cases, last very long, either...

...and, that actual freedom-of-speech fades one more little bit when each GA ''fades'' too......

I understand, personally, that doesn’t bother me,... it normally comes from the ‘cancel culture’, which on this site also happens to consist of weaker ‘professionals’ especially the academia types.
I seen it lately, and I’d point it out.

I look at them as my groupies, I’ve noticed they also like to stroke each other, Because the adage misery likes company.

Anyways, when they go Off Topic on posts, I know the cohorts are reading and still following me. I use it almost like a barometer, more times then not,... when marked OT, it means I’m on the right path, Especially when there are still those that would cancel the OT with a GA.

^{Currently waiting for this post to be marked off topic... lol}

Here's a GA to make up for the one that was (negated) on

...post #26.

As my ol' Pappy used to say"If you throw a rock into a pack of dogs,the one that gets hit will holler?"

What's worse is when you see these :engineers" in a real job that requires real knowledge and are very dangerous,especially electrical engineers.I have met a few that, if they were engineers,the woods are full of them.

I have also met several technicians that were more capable than engineers at solving highly technical problems.

They had no degree,just learned on the job over many years of experience.

They probably could not pass an engineering exam,but demonstrated skills and knowledge far above their pay grade.

As per Post 41, the question was, in effect, how do projects get made better during design and construction (i.e.: simpler, safer, better, etc.).

The poster showed that he addressed such issues when he changed his approach from I-beams to a rail car, which may be simpler, but may not be safer.

Effective discussion of safety is integral to any construction project, and therefore, is always on-topic, and is ignored at the (responsible ?) party's peril, as a minimum...

Here a FYI that I’ll just put this on the table.

in wisconsin, the money gained from snowmobile licenses, some of the money for these licenses go to, subsidizing snowmobile trails (To a certain degree).

i recall, (this was about 30 + years ago) there was a huge uproar, that in a project, a subsidy was paid for a bridge for snowmobiling on an established trail. I believe it was $40,000-$80,000 I don’t recall, but it was an Exorbitant Amount, That was subsidized.

the uproar was, the cost just for a snowmobile Bridgett was similar to one of the picture SE posted.

Of course, it would need to be open to public use.

I also have an FYI to offer. This happens all the time on Facebook. Someone will post something, and dozens of people respond without taking the time to read the previous responses.

That said, if you haven't already, go back and read #17. (It was written by the OP).

Reading every comment after #17 is optional.

Being a community and like a lot of threads on CR4, problem taking care of, And posts wind down with just loose ends remaining that are being tied up.

for the reader, Reading is optional after post #17.