Building a bridge?

[BoneDigger]

I have a small creek I need to build a bridge across. The span is only about 6 ft but I would probably build it out 12 or 15 ft. I was thinking of using 4 x 6 lumber as the main support. I'd put them 2 ft apart and use 6 for a width of 12 ft. Then I'd use 2 x 6 treated for the cross pieces. Would that be strong enough to hold a standard farm tractor (35hp) with attachment? I know it would be fine for my Ranger, just not sure about the tractor. I would of course anchor the bridge as well.

Thoughts? Bad idea?

 

[fried1765]

If you can support both sides of the bridge at the 6' center distance, you should be ok.
If you can only support out at the 12'-15' length....NO!

 

[Diggin It]

How deep, and what passes through/under?

 

[Rebeldad1]

Look for a old 20' shipping container thats trashed. Should be able to pick it up for nothing. Strip it and use the floor.
or
A old trailer, 5th wheel frame. Same thing with lots of strength.

 

[BoneDigger]

It's maybe 4 or 5 ft to the bottom. A creek passes under.

So, you would think I would need to add a center support?

 

[Diggin It]

A creek passes under.

A trickle or a torrent?

Thinking a couple of pieces of 24" culvert side by side with your wooden bridge over top using them for support. But if the water has a tendency to get higher and rush, that may not be feasible.

 

[4570Man]

I’d use a junk trailer. You can buy them a lot cheaper than you’ll be able to build a suitable bridge. And a 4x6 on a 24” center isn’t nearly strong enough IMO.

 

[RalphVa]

I have a small creek I need to build a bridge across. The span is only about 6 ft but I would probably build it out 12 or 15 ft. I was thinking of using 4 x 6 lumber as the main support. I'd put them 2 ft apart and use 6 for a width of 12 ft. Then I'd use 2 x 6 treated for the cross pieces. Would that be strong enough to hold a standard farm tractor (35hp) with attachment? I know it would be fine for my Ranger, just not sure about the tractor. I would of course anchor the bridge as well.

Thoughts? Bad idea?

I went through this a few months back, thinking I needed to move my present tractor crossing which was a PITA in 2018 with the huge amount of rain we had. This year, it has been fine with its 5 or 6 six inch PVC pipes underneath piled up rocks, concrete and packed soil, like so many years before 2018.

If I was to move it downstream, it was to a place where the width was about 6 or 8 feet. I was looking at putting in 5 railroad ties and covering them with 2x6s with fairly wide spacing (2x6s would be perpendicular to the ties, to "tie" them together), just close enough to keep my tractor tires from going through. Got this from talking to other men at church who had built bridges for big tractors to do over.

I was thinking of getting a boom pole for the 3ph to pick the ties up and set them across the opening. I'd set at least one tie on each side of the crossing in parallel with the stream, hopefully recessed a bit so that I wouldn't need a ramp to get upon the 2x6s atop the cross-the-stream ties and all. Could just set a 2x6 there. Could possibly do without the initial ties or 2x6s and join the ties above with the 2x6s across on top. Having those initial ties or 2x6s would just make it easier to move the longer ties to get them positioned properly.

This is the thinking that I went through. Even got a location/business for 12 ft ties.

The old crossing is fine as long as we don't have the deluges to keep dumping silt in and plugging up those 6 inch PVC pipes underneath. Seem to only need a couple working to carry the normal stream flow.

Ralph

 

[3Ts]

A trickle or a torrent?

Thinking a couple of pieces of 24" culvert side by side with your wooden bridge over top using them for support. But if the water has a tendency to get higher and rush, that may not be feasible.

If you put in a culvert, be sure you check to see what the watershed area is and the capacity of the culvert to pass the expected runoff. There are charts to determine culvert size. As for bridges, here's an engineered bridge plan:

https://www.fs.fed.us/t-d/pubs/pdfpubs/pdf12232316/pdf12232316dpi300.pdf

 

[RalphVa]

I’d use a junk trailer. You can buy them a lot cheaper than you’ll be able to build a suitable bridge. And a 4x6 on a 24” center isn’t nearly strong enough IMO.

Hey, that's an idea. A local Kubota seller sells the tractors with loaders, bush hog on a trailer as a package. I was wondering where I could park the dang trailer. It could go across my stream at a point a little downstream. No trailer licensing, etc.

How the **** do you get the trailer across the stream though? Hot air balloon to hold up the *** end?

Ralph

 

[4570Man]

Hey, that's an idea. A local Kubota seller sells the tractors with loaders, bush hog on a trailer as a package. I was wondering where I could park the dang trailer. It could go across my stream at a point a little downstream. No trailer licensing, etc.

How the **** do you get the trailer across the stream though? Hot air balloon to hold up the *** end?

Ralph

I’ve seen plenty of semi trailer bridges. I assume most of them were set there with a trackhoe. Maybe you could drag it across.

 

[RalphVa]

If you put in a culvert, be sure you check to see what the watershed area is and the capacity of the culvert to pass the expected runoff. There are charts to determine culvert size. As for bridges, here's an engineered bridge plan:

https://www.fs.fed.us/t-d/pubs/pdfpubs/pdf12232316/pdf12232316dpi300.pdf

Thing with culverts is you need to somehow protect soil, etc. on top of it from being washed away in a flood. I've had my little stream submerged 6 ft under post Isabelle, and it was 12 ft over in May of 2018. Many other times, I've had to repair the top part after flooding less than these.

I put in a little "people" bridge near where I have in mind for a new tractor bridge if I do so. I've it anchored with some long metal bars into the soil on both sides, to keep it from being lifted out. Culverts need to be metal to keep them from being lifted out, too. Fiberglass ones can be lifted out.

Ralph

 

[drssg]

If you follow the creek up or down stream, it should go under a public road somewhere. That would give you an idea of how big it needs to be.

I used a single culvert about 5' in diameter, because that's what the county did.

 

[aczlan]

I’d use a junk trailer. You can buy them a lot cheaper than you’ll be able to build a suitable bridge. And a 4x6 on a 24” center isn’t nearly strong enough IMO.

Yep, I would look at bringing in a flatbed semi trailer and having someone with a large excavator set it in place after removing the wheels and landing gear.

Aaron Z

 

[jimmychew]

Here's the one I designed and built. 20 yards of 4000 psi concrete and a bunch of #8 rebar and it will handle a loaded 10 wheeler.

 

[Deere Dude]

I have a small creek I need to build a bridge across. The span is only about 6 ft but I would probably build it out 12 or 15 ft. I was thinking of using 4 x 6 lumber as the main support. I'd put them 2 ft apart and use 6 for a width of 12 ft. Then I'd use 2 x 6 treated for the cross pieces. Would that be strong enough to hold a standard farm tractor (35hp) with attachment? I know it would be fine for my Ranger, just not sure about the tractor. I would of course anchor the bridge as well.

Thoughts? Bad idea?

Don't see why it wouldn't work. I would get a couple pallets of redicrete (cheap at Lowes) and form a base 3 or 4 'wide x 12' on each end to anchor it so it hopefully won't float away on you if it floods a little.. This will help minimize erosion. Set the beams overlapping the concrete and bolt it down. I would cap it with 2x10s but maybe 2x6s would be alright.

Just my opinion be 4x6s may work, but bigger is always better. It would be a hoot to redo it. Check the span and load charts to see what is acceptable. Figure your tractor with a bucket of gravel on the center of the bridge, even though half the tractor can only fit at a time. May also pour a wall at the lead end and foot end or the tractor will tear up the boards when climbing on.

 

[radios1]

your creek may be able to support a good size hydroelectric generator!. screw type. you can recoup the time, money and effort making the bridge with free electricity!..

 

[travlitt]

I wouldn't use a shipping container floor at all. They are designed to support load at the 4 corners.

 

[3Ts]

your creek may be able to support a good size hydroelectric generator!. screw type. you can recoup the time, money and effort making the bridge with free electricity!..

You'll need about a 10 gal/min flow rate with about a 60 foot fall to generate 1Kw of electric power.
hydroelectricity power and energy calculator - free online

 

[4570Man]

Well I doubt the creek has 60 feet fall but it’s probably way more than 10 gpm. You’d probably need a battery or so other storage device. Does anyone know how much power it would take on a continuous generating cycle to power a house?