Bridge possibilities

[RobA]

I am still looking at making a creek crossing for my tractor (posted here a few months ago). Creek bed is about 4 feet deep and 8-10 feet wide (mostly from erosion). Previous owner had a 42 inch galvanized pipe culvert which got washed out. I would reinstall it but it is only 9 feet long and would not be wide enough for a tractor crossing.

I was thinking of making a bridge instead but don't want to pour concrete footings for various reasons. Does anyone have any thoughts about buying an old flatbed trailer (say 35 feet long), cutting the wheel assembly off and laying it across the creek? With such a long bridge over such a short crossing I was thinking I wouldn't have to pour any footings.

By the way, I did price out plastic culvert pipe from local suppliers. A 20 foot piece of 42 inch HDPE would cost me close to $1,000. There is a local salvage yard selling a 1965 35' Freuhauf single axle flat bed trailer for $1,250. I have also heard of using an old flatbed railcar (from a post here I think) but they cost more than I want to spend.

 

[Tim_in_IA]

could you post a picture of the bridge area please? I think I remember your post from before but not too sure. Were you the guy that was going to use cedar trees to make a bridge?

 

[RobA]

That wasn't me. I'll try to get some pictures this weekend when I am there.

 

[Tim_in_IA]

Oops! Sorry for the mix-up. Pictures will help a great deal.

 

[HomeBrew2]

I helped a friend do that about about 20 years ago. I had the torch, they had everything else. I think it may have been a 30+'er but maybe shorter. It was an older trailer that had the frame fishplated (strongbacked). Their stream was a youngster so it was not too wide but steep sides and carried a lot of fast water. They tried to position it by pulling with a tractor and pushing with house moving jacks but couldn't get it. They finally asked the neighbor with a small (D2-3) Cat to push it into place. Worked out great!
Cheers!

 

[Highbeam]

Bridges are almost always better than pipes from the fishy point of view. Even the flatbed trailers have weight ratings. I would try to research whether that trailer was built to be loaded heavy or to load something very light before buying it.

The farther the bridge extends onto the land on either side, the less likely you are to need any kind of footing.

 

[BB_TX]

I think the trailer is a good idea. That is what I am planning, except that I am planning on some concrete footers. My creek is more like 15'-20' wide and 10' deep. And it does occasionally flood. I don't want all that water pushing against the trailer once I get it set in place so I plan to raise it a little above grade. If you don't have that much flow, then probably not a problem for you. I have located a 40' trailer and am working to get possession of it. Then I will have to figure the logistics of getting it to my place and then set across the creek.

 

[JeffRey30747]

RobA,
I have two 48" x 16' galvanized culverts for my driveway crossing and I don't remember them costing near that much. But that was seven years ago and steel wasn't near the price that it brings now. After going through the possibilities for bridge designs, my father and I both decided that the culverts were the best alternative for me. We reinforced the ends with cinder blocks poured full of concrete and steel rods driven into the creek bed and they are still there today and have given excellent service.
Jeff

 

[cmuncy]

Along HI 80 ( or is that 40) going up to Echo SUmmit towards Lake Tahoe, you will find several flat bed rail cars used for bridges traversing some of the many streams in the area.

No footers were typically used but conctrete or asphalt was used at the beginning and end of the trailer/bridge/rail car.

 

[have_blue]

If the crossing is only 10' wide, you have very good options for bridge design. There's a huge difference in a 10' bridge and (for example) a 20' bridge. A 10' long bridge doesn't have to be real beefy to support a 10,000 pound tractor with perfect safety. You could even build it to support 30,000 pounds for a huge safety factor, and it would still not need to be real beefy. You won't need any fancy footings either. Just something wide enough to prevent the beams from sinking into the soil.

I would build it from 4 10' I beams of sufficient size, probably 1 footers lightly latticed, with a few diagonals to triangulate. Deck could be treated (dimension) 2x6, 2x8, etc. Footings could be cross ties. In fact, the whold bridge could be made from treated dimension 2x lumber, with 4 big laminated beams replacing the I beams.

You can have fun with a 10 footer. Just build it 2x or 3x stronger than needed, and you can't go wrong. If it needs to be longer than 10', all bets are off! /forums/images/graemlins/smile.gif

Whatever you decide to build it from or use, high water is a far bigger concern than strength. If the water comes up pretty high, say 5-6' depth and swift, you will need to anchor the bridge down real good. That isn't hard to do either for a 10 footer. If the water gets very swift and/or comes up say 8', your options quickly vanish. Big rushing water is a monster, and will defeat you if you take it on head-to-head.