Building a Bridge suggestions?

[paintman161]

Okay so I want to build another bridge on my property, Last summer I re-did the old RR bridge and it turned out very nice! This year i was thinking of adding another bridge to cross another creek on my property. The problem with this one is I am starting from scratch. The creek width is about 40', but one issue is during the spring it likes to flood and the nearest banks that are high enough are about 150'-0" apart. I want to try doing this with wood (steel is too expensive). I have a lot of Ash on my property so i was thinking of maybe utilizing those trees?? I don't want anything in the center of the creek for supports since this is where the main water flows and gets going really fast during spring/ thaw. So that clear span would need to be 40'-0, the rest can be what ever. As for the width, maybe 4' or 5' just enough for an ATV to get across.

Picture shows looking up stream, you can kind of see the other bank which is higher in the background.


Any ideas on how to go about this?

 

[JoeL4330]

Index A versatile and scaleable bridge design for spans up to 50 feet, build foot bridges, design construction of foot bridges, constructing footbridge design, free bridge design, gartenbrücke, how to build wooden bridge beams, instructions for woode

http://www.fpl.fs.fed.us/documnts/misc/em7700_8_chapter02.pdf

Bridge Basics - A Spotter's Guide to Bridge Design

 

[paintman161]

Thanks for the information! It's a start.

 

[rd_macgregor]

Buy a 40' shipping container and torch the superstructure off for scrap (or, maybe you'll get lucky and find a flat deck or flat rack container, and not have to deal with sides and top). I think these containers have nearly a 20T capacity. Support/abutments is the next issue. My preferred would be a couple of steel piles on each side with a steel beam across the top. My second thought was burying Jersey barriers on each side as abutments...but I have well-defined banks where I want my bridge, so this might not work for you.
Your ash trees might work, but steel and/or concrete would outlast them, I bet.

 

[paintman161]

Buy a 40' shipping container and torch the superstructure off for scrap (or, maybe you'll get lucky and find a flat deck or flat rack container, and not have to deal with sides and top). I think these containers have nearly a 20T capacity. Support/abutments is the next issue. My preferred would be a couple of steel piles on each side with a steel beam across the top. My second thought was burying Jersey barriers on each side as abutments...but I have well-defined banks where I want my bridge, so this might not work for you.
Your ash trees might work, but steel and/or concrete would outlast them, I bet.

although a great idea, not very practical for me, wont be able to get a shipping container across, plus finding one around here is impossible. Also i have no welding or cutting capabilities.

 

[paintman161]

I was thinking about buying some Larch trees like 10" dia and sink them into the ground 36-48" (pilings) and use 2x10 rough cut for the beams across the top of the pilings. Then get some 50' trees and lay them across for my main beams and use 2x on top for decking. I was thinking only spacing them like 3'-6" or whatever the width of the ATV tires are.

 

[LD1]

Using your own trees without a way to treat them is a recipe for disaster in the near future.

And while cutting up a shipping container "may" work for your light loads, I wouldnt advise it as alot of the strength of them come from the sides and top. Picture a A box beam (or box tubing). Once the sides and top are cut out and you are just left with a flat piece of steel, it isnt very strong.

For a 40' clear span, I think you need to look at some sizable steel beams.

 

[paintman161]

Using your own trees without a way to treat them is a recipe for disaster in the near future.

And while cutting up a shipping container "may" work for your light loads, I wouldnt advise it as alot of the strength of them come from the sides and top. Picture a A box beam (or box tubing). Once the sides and top are cut out and you are just left with a flat piece of steel, it isnt very strong.

For a 40' clear span, I think you need to look at some sizable steel beams.

Maybe i will just make a suspension bridge for foot traffic only.

 

[davrow]

Maybe i will just make a suspension bridge for foot traffic only.

Foot traffic only? Then you can put in a zip line each way! :laughing:

 

[Oldtractorfixer]

We bought a used flat bed semi trailer. 45' X 8'. Guy we bought it from delivered it and kept the axles. Pulled it across with a winch on our D4. All steel and aluminum as on the highway caarries 40k. Added a hand rail and were done.

 

[LD1]

An actual flat bed trailer would work well too. But a box trailer, if you cut the sides and top out, would be the same as I mentioned earlier about the storage container.

 

[JoeL4330]

would you consider putting in a good ford (as in fording)...

 

[2458n]

We bought a used flat bed semi trailer. 45' X 8'. Guy we bought it from delivered it and kept the axles. Pulled it across with a winch on our D4. All steel and aluminum as on the highway caarries 40k. Added a hand rail and were done.

This is the least expensive way to do it right. I might have to do it at night but in the morning it is done.

 

[rd_macgregor]

I had assumed that you wanted to drive a tractor or other heavy vehicles over the bridge. If it is just for foot traffic, ATV's or snowmobiles, then you can get by with a lot less bridge. I built a 40'x 6' footbridge across a (small) floodplain about ten years ago. It is supported by square steel tubes driven vertically into the bank and spaced across the floodplain, with heavy steel angle iron bolted across the tops of the tubes, then PT beams on the angle iron and PT decking across the beams. It has held up really well so far and will hold an ATV no problem...I even debated driving my small truck across, but decided the downside of being wrong about the strength of my bridge would be too great (ie, my wife's reaction if I collapsed the bridge and dumped the truck in the stream)!

The main clearance/opening of the bridge for the stream is probably 5'X10' and the rest of the bridge is about 18" to 2" above the floodplain.

It took me the better part of a week's vacation to build and keeps my feet dry on walks.

If I didn't need to take my cabbed tractor across my main stream crossing, I'd consider using a shipping container as a covered bridge: just take out both ends and weld bracing gussets at the upper corners.

 

[Oldtractorfixer]

Cheapest I could figure out. Paid $2500 delivered for the trailer. Added a couple loads of 2" rock to sit it on. Back filled to the rock. Then the hand rail. I will add a picture tonight when I get home.

 

[Oldtractorfixer]

 

[b73]

A friend has used flatbeds for years at a rural property.Relatively cheap and quick setup when you have the equipment.He always laid trees across for foot traffic and 4 wheelers then he decided to clear the land and needed to get the dump truck and equipment across and came up with the same great plan.

 

[WPSmolder]

I built a bridge on my farm last summer using telephone poles running across with a wooden deck on top. So far the bridge has done great. I use it to access a big portion of my property that is cut off by a creek. I drive my truck and tractors over it quite often and it does great. The best part is the little money that it cost to build.

 

[Jim Timber]

What are you guys paying for semi flatbeds?

 

[paintman161]

I built a bridge on my farm last summer using telephone poles running across with a wooden deck on top. So far the bridge has done great. I use it to access a big portion of my property that is cut off by a creek. I drive my truck and tractors over it quite often and it does great. The best part is the little money that it cost to build.

pictures?