# Building a 10' vehicle bridge



## Mattie420 (Apr 2, 2013)

We are taking down our old creek bridge and building a new one. The creek is only about 8ft wide but I was going to use 12ft long telephone poles as the support and bury them in the ground on both sides so they are in tight, then use PT 2x6's as the cross boards and then more PT 2x6's going the same way as poles for the tire tracks. Well I got the mini excavator reserved for the weekend and I have the rest of the wood ready but when I went to go pick up the utility poles, the 12ft long ones are only about 6.5" in diameter...if I wanted thicker poles I needed to either buy a 25ft pole and cut it (I don't have a working chainsaw) or find some on craigslist that are already cut down to size. Well now that its done and I have these smaller poles im wondering what everyones opinion is on using them. Like I said the length of the gap is only about 8ft and im only planning on using it for regular passenger vehicles (cars, trucks, SUV's) Do you guys think one of those poles laid on its side can hold up one side of a vehicle or should I double them up and put 2 poles under each tire track? I think since its only gonna be a quarter of the weight of the car (one side of the car and then when the front wheels are on ground or close to it the back wheels will just be getting on the bridge) ill be fine but I really don't want to do all this work and then it cost me double because the bridge collapse the first time I use it so I need your opinions


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## wy_white_wolf (Oct 14, 2004)

Double them up. I would consider tripling them. While you only plan on a car some yahoo could come along and try with something a lot bigger.

WWW


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## mreynolds (Jan 1, 2015)

It would probably be fine by doubling them for light traffic _if_ it is only 8' and no more. But here is the thing you should know. Most poles are not structural grade but instead #1. Structural grade is more dense and will hold more. 

One more thing to consider. Will you never have to pour concrete ever again across that bridge? Or a neighbors bull dozer or 90 horse tractor? Maybe you could find some used bridge timbers like 4 x 12's. Found some possible sources for your area. 


http://www.greenecoservices.com/reclaimed-wood-salvage-fsc-timber-nc/


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## Mattie420 (Apr 2, 2013)

Thanks guys!!


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## oldasrocks (Oct 27, 2006)

I'd use steel to build a permanent bridge. You could use 4 X 4 steel tube with 1/4 walls if you pattern it to a King and Queen system for strength. Sorry I don't know how to draw on here. Look up bridge designs.


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## jwal10 (Jun 5, 2010)

I would buy 6 of the big ones, 3 to a side and cut small end for fence post. Also dig off a place and put 1 on each side of creek at the 8' measurement between, to support the 6 as an abutment to support the poles and keep the bank from sloughing off from the movement of the poles, when you drive across. Best would be a concrete footer. I would use deck screws to tie everything together instead of nails. Cross 2xs into poles. Those double thickness length 2"Xs all the way through the cross 2"Xs. I would run the double length 2Xs all the way to edge of bridge, then double up a "bumper" along edge.


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## KMA1 (Dec 9, 2006)

Not to put my vehicles across. Or my wife and kids.


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## farminghandyman (Mar 4, 2005)

why not consider using steel, find a heavy trailer bed and copy it, below this is very similar to how my sons goose neck trailer is made and has a 21,000 LB rated capacity and he has hauled up to 35,000LB on it, it is 28" foot long deck,


stringers out of 12" channel and cross members out of 3" channel, spaced about ever 24", 16" better as if topped with 2x lumber decking, if the lumber would break, the wheel of the vehicle would not drop clean in to the hole created, 

or cover with some 3/16 or 1/4"steel tread plate, decking, my son did this when he was hauling scrap steel,this is very similar to how my sons goose neck trailer is made and has a 21,000 LB rated capacity and he has hauled up to 35,000LB on it, it is 28" foot long deck,

look at a heavy Goose neck trailer and copy the basic design, one could easily extend the width to 10 foot,even 12 foot wide if wanted, to, 

pour some good deep concrete footers on the ends and set it in or build it in place,


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## meiere (Dec 17, 2014)

What about having to get a firetruck or ambulance across?


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## farminghandyman (Mar 4, 2005)

one could consider a larger culvert, one could talk to a scrap dealer and see if they have any diesel fuel tanks that have been dug up. they may even cut the ends off it , 

people around here cut them apart an use for cattle shelters, 

I built a cellar out of a used 10 foot tank, with a rotted out bottom, 

but one can buy new culvert, who knows the county may have a used one that they replaced with a larger unit,


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## chuckhole (Mar 2, 2006)

Don't go on the light side of something like that. Remember that you also have to consider the weight of all the lumber on top of those poles (when wet).

And like someone already said, it will get used for vehicles other than what you intended it for. I would also consider 12' wide and not 10'. And maybe a short guard rail to help with visibility in poor weather conditions.


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## fordy (Sep 13, 2003)

..............A fully loaded concrete truck with 10 yards on board is going to weigh over 70,000 lbs ! , fordy


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## texican (Oct 4, 2003)

I'd drive an atv over it.... but a truck or car or tractor? Uh, sorry, no. 

Now, if you had 12" telephone poles, and did some cross braces on both sides, on both poles, then crisscrossed with 2x6's, I might try that.

From experience, overbuild at every point along the way, and plan on a hundred year flood... otherwise it'll all wash away.... too 'low', and it acts like a dam on the creek, and tremendous side forces will pull/push it all down the creek...


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## termite76 (Apr 3, 2015)

My sister used an old salvaged steele silo and back filled to cross their creek. I agree with others I haul some pretty hefty loads in the old truck and wouldn't want to cross a bridge as light framed as described.


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## Bearfootfarm (Jul 13, 2006)

We generally use poles as long as possible, and use a solid layer of them.

We then cover them with tarps or plastic and soil so grass can grow over them.

They will support huge tractors and combines, as well as fully loaded dump trucks

I wouldn't trust a bridge with just 2 feet of support on each side unless it sat on concrete pillars


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## agmantoo (May 23, 2003)

Have you considered fording the creek? No larger stream than your going to cross just pour concrete in the stream bed and drive across. Should last and have no concern for caving in or driving off the sides.


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