Plans for a small bridge?

[harwill]

For what it's worth, we made a small bridge about fifteen years ago using two creosoted "switch ties" about 20' long, set on regular ties let into the bank. Rebar pins held it together and it was planked with treated 2x8 pine. Still driving 3/4 trucks over it today. Almost had a heart attack when we found out the VFD had driven a tanker over it to reach water and then came back loaded!
Ties come in different sizes according to usage. Get the bigger ones.

 

[RxRatedZ71]

I built a wooden bridge across my "feeder stream" finger last summer. It spans about 22ft. I managed to snag 4 electric poles from a guy on Craigslist who only lived about 15 miles away, who delivered them for $100. They were about 16-20" diam at the butt-end and about 30' long. I just wanted to be able to drive my Polaris Sportsman over the bridge to my future barn-site, so I elected to only use 2 poles (the other 2 are currently being used to build a foot-bridge over my main creek). I spanned them about 4' apart to match up with the vehicle width. I decked the bridge with PT 2x8s and used counter-sunk lag-bolts to secure them to the bridge beams. I secured the beams to the banks by burying them about 15 inches down. I dug a trench under the end of each pole and filled it with several sacks of quick-crete and then ran some re-bar through the utility holes of the power poles. On either side if the bridge I secured PT 4x4x12' posts into the creek-bed then ran lateral supports the either side with PT 2x12s. This all me be over-kill for only needing to support a 800lb ATV but I bet it might support significantly more. I've debated whether to drive my JD tractor over it, but as my wife puts it, " Your not driving that tractor over anything that YOU built, at least while we're still making payments on it!"

 

[Bartcephus]

At my hunting lease, we have two bridges built using power poles as main beams. I was leary of them at first but after seeing the others drive their big tractors and big trucks over the bridges, I am quite impressed. The bridges span over quite a drop. Lately however, I have one bridge which I avoid now because the washout is removing the soil beneath one side of it. They have been there for several years and have held up well. Just a little concerning now...

 

[RxRatedZ71]

Okay, so I snuck away this afternoon to take some pics of my bridge. The first shows the decking and overall length. The second is a shot while in the creek-bed showing the power poles which provide the main support.