atv bridge beams ?

[gadeerwoman]

Thread about the homemade beams rang a bell. I'm in the process of replacing an atv bridge across a small creek. Old bridge was build using 16' 4x4's and marine plywood for top (painted with exterior barn paint). Old one got washed out after a couple heavy rains that totaled over 7 inches. I'm wanting to move the new bridge upstream to where it will be on higher ground but I'll need to span at least 20' foot across to be more secure. Longest 4x4's I can find are 16 footers. Ideas on how to tie maybe a 16' to an 8' to make a longer beam span? Only thing that will be crossing the bridge will be atv and a riding lawn mower. Mobile home beams are not an option (no way to get them to the creek site and span them across) so wood is the only option. 4x4's from the last bridge are still solid, no signs of rot so I'd like to use those along with 4 existing 8' 4x4's I have on hand. Bridge will be only about 6-8 foot wide. I had thought about running a 2x8 section of board underneath the 4x4's at the join and bolting it thru.
Suggestions?

 

[treemanjohn]

Why can't you get steel to the site?

 

[Spotlite]

Done a few crossings and had washed away problems. We finally started ramping both sides of the creeks and putting rock in. But for 20 foot I’d hit the power company up for old poles. Lay about 4 of them across there and floor it. We used 8 laying about a foot apart to span 15 foot and crossed it with a tractor.

 

[ryanh487]

Either old power poles or triple up 2x8's for each beam with a good 3-4' overlap held together with lag bolts. You'll have 2 6x8 beams and they should hold up well.

 

[NE GA Pappy]

you can buy 6 x 6 x 20 pressure treated. The local company that makes pole barn trusses has them in stock. They are somewhere around 150 each

 

[gadeerwoman]

Only way to get to the site is to drag whatever I use with the atv and then drag across to the other side by hand. So anything that weights much limits me. With a small atv I can only drag so much. Home Depot and Lowes are the only local places that I've found and 16' is as long as I've found so far in anything. Plus with no long trailer to haul it's been a pain.

 

[Big7]

Cedar logs are better than any store bought wood. They are very strong and last a lifetime.

There are cedar fence posts on my family's farm that my Granddaddy set in the 1920's. Still hard as a rock.

You can probably find some close by if you have dirt or know someone that does. And.. It's free.

10 or 12 inch poles will hold up just about anything short of a D9.

 

[georgia_home]

I found some I think 4” diameter poles. Maybe 22’for ours. 2x8 or 10, forget offhand for decking. Still solid, chained to trees.

 

[Spotlite]

Only way to get to the site is to drag whatever I use with the atv and then drag across to the other side by hand. So anything that weights much limits me. With a small atv I can only drag so much. Home Depot and Lowes are the only local places that I've found and 16' is as long as I've found so far in anything. Plus with no long trailer to haul it's been a pain.

If you’re going to have to “two piece” it, you have 8 foot 4 x 4’s on hand? Get the 16 footers, bolt 2 x 4’s on both sides of your joint and stiff knee under the beams about 6 foot apart - just make sure those joints get a stiff knee.

Post hole your stiff knees about 2 foot in the ground.

 

[mguthrie]

Where are you located? Building supply stores can get long length lumber. Lowes or HD may be able to order them for you. I’d double up 2-6x6x20’ and space them about 42” apart. I wouldn’t free span a spliced beam. Deck with marine ply or PT wood. The power poles may be a cheaper option.

 

[Gadestroyer74]

THe only thing that’s gonna last is telephone poles. Any other Lumber will rot in 10 to 15 years. As mentioned above used telephone poles will last a long time

 

[fireman32]

I’d go with utility poles as well. The last ones I got varied from 28 to 32 feet long. I’d be surprised if you couldn’t cut them to 20 feet and haul them on a 16 foot trailer. Make sure to remove the ground wire before you cut it with a chainsaw. A 4-wheeler May struggle to pull them unless you can attach some wheels to them. I have ratchet strapped a set of hand trucks to them and pulled them that way.

 

[NE GA Pappy]

if all you have is a 4 wheeler, maybe you need to find a neighbor or a friend who has a smaller 4x4 compact tractor to pull the lumber in for you. Even a 25hp 4x4 compact tractor will pull in a lot more than a 4 wheeler, mostly because you can chain off to the lift arms and pick up one end of the pole an add that weight to your rear wheels for more traction

 

[earlthegoat2]

THe only thing that’s gonna last is telephone poles. Any other Lumber will rot in 10 to 15 years. As mentioned above used telephone poles will last a long time

Not entirely true but it may be depending on the geographic area.

Around here we can get 2.5 CCA treated Timbers rated for saltwater. Dock builders use them all the time. I used the dock builders lumber yard and got 6x6s treated the same way telephone poles are which is 0.6 CCA for a pole barn. They pressure treat them right there after they are milled.

Like I said, geographic area may be a limiting factor and I don’t know what the availability of these supplies are inland. The same place that makes the telephone poles can treat other lumber too And likely does. If your near one of those, your in business.

There is still a large market for CCA treated wood even though it has been banned for many applications. It is still used in saltwater areas, freshwater docks, and permanent wood foundations which pole barns and bridges are an application.

You might be able to get Timbers from a pole barn builder or find out where they get them.

 

[Spotlite]

@gadeerwoman keep in mind that you can rent a mini excavator or small tractor from Home Depot for $300 per day and can pull their small one with a half ton truck.

 

[Gap53]

Thread about the homemade beams rang a bell. I'm in the process of replacing an atv bridge across a small creek. Old bridge was build using 16' 4x4's and marine plywood for top (painted with exterior barn paint). Old one got washed out after a couple heavy rains that totaled over 7 inches. I'm wanting to move the new bridge upstream to where it will be on higher ground but I'll need to span at least 20' foot across to be more secure. Longest 4x4's I can find are 16 footers. Ideas on how to tie maybe a 16' to an 8' to make a longer beam span? Only thing that will be crossing the bridge will be atv and a riding lawn mower. Mobile home beams are not an option (no way to get them to the creek site and span them across) so wood is the only option. 4x4's from the last bridge are still solid, no signs of rot so I'd like to use those along with 4 existing 8' 4x4's I have on hand. Bridge will be only about 6-8 foot wide. I had thought about running a 2x8 section of board underneath the 4x4's at the join and bolting it thru.
Suggestions?

My son and I built one last year using 3 30 ft power poles top with 2×6 and adding metal post for support underneath. Supported a 30 horse jd tractor with no problem

 

[BriarPatch99]

Find a junked out mobile home ...rip off the house part and use the frame ... wheel it where you want it(getting it across the creek may be a problem) ....but once in place remove the springs axles ... cover it with the type wood needed ...

 

[fireman32]

Find a junked out mobile home ...rip off the house part and use the frame ... wheel it where you want it(getting it across the creek may be a problem) ....but once in place remove the springs axles ... cover it with the type wood needed ...

Reminded me of a man that used a flat bed semi trailer for the same purpose, just cut to length. Bet a old roll back bed would work too.

 

[Darkhorse]

Many years ago while I was still a young man I worked a while with my older cousin on a timber crew he owned. Mostly we harvested in the flint river swamp as he had a lot of land and leased a lot more.
When ever we came across a slew (slough) that needed bridging he would calculate the length and width needed and we would find 6 to 8 trees and cut them to use for a bridge. Using shovels two long notches were cut on each side, then squared with flat shovels. The poles were set in the notches spanning the slew. Then a length of chain was cut for each end that was placed across the logs then spiked into place. The chain served to keep the logs from spreading apart under a load. Many times a plank was affixed to the outside of the logs to keep tires from sliding off. Some of these makeshift bridges served for a long time and served us well holding heavy log trucks and skitters.
For an ATV everything would be downsized making building a bridge much simpler. And no special 4X4's or 6X6's would be needed.
I'm almost 70 years old now and people who worked outdoors seemed more self sufficient than they do now.

 

[taylornelms]

I actually just did this. I have a small winch that is rated for 500 lbs that is powered by a battery powered drill. Between that and the winch on my ranger and a snatch block I was able to get them across.