How strong is my wooden bridge?

[Kenneth in Texas]

You could probably drive your tractor across it, providing you're in the highest gear possible with the highest throttle setting, faster the better :laughing:

 

[daugen]

guys I'm really impressed by and appreciative of your ideas; some of them are pretty neat.
Seems to me a wood bridge is a high maintenance item, but then most of us like them. Well, TxDon has taken that to another level...:thumbsup:

I think the culvert pipe makes the most sense. I don't have a backhoe; though boy what an excuse to go rent one of those little mini excavators. When we get one of our common three inch rains here, that ditch for sure runs water, but it has been dry here for over a week other than showers. The ditch bottom felt firm under my feet. The farmer's field ditch coming into it is much bigger, and has been dug deeper for sure, so there is a potentially large amount of water that could flow through here. The bridge would be a choke point so whatever I do it has to be a big pipe. And I know absolutely zero about culvert pipe, but I sure am going to learn.

It would be nice to have this be attractive as well as functional. For now I want to get to the other side and this winter go logging in the woods back there, clearing a path to that pond that is totally hidden in the middle of twelve acres.
If it does turn out nice back there, so folks might want to walk back there and sit by the pond, well, yeah, then I might like to have a pretty bridge to go over.

 

[Ken45101]

Is the ditch wet? From the pic it looks dry. I would dig the edges back some and put a road right thru the ditch. Next choice would be a culvert.

That's what I was thinking too. Dump some rock along the route for improved traction and to keep from sinking in when it's wet.

As that bridge is now, I wouldn't drive anything across it.

 

[Egon]

You could probably drive your tractor across it, providing you're in the highest gear possible with the highest throttle setting, faster the better :laughing:

On bridges a slow speed is usually recommended to reduce impact loading.

 

[Egon]

That's what I was thinking too. Dump some rock along the route for improved traction and to keep from sinking in when it's wet.

As that bridge is now, I wouldn't drive anything across it.

That might be the cheapest plan.

 

[FTG-05]

On bridges a slow speed is usually recommended to reduce impact loading.

His point, I think you missed it. Think "01" in orange.

 

[kevinwak]

What is the worst that would happen if you drive over it now and it failed? Probably very little due to it only being a couple feet off of the bottom. Throw a couple planks, preferably 3X12, but a pair of 2x10's on top of each other would do, onto it to match your tire width and test it out. The fresh planks will help spread your load. The worst that could happen is the bridge breaks and you are replacing it, which is what everybody is telling you to do anyway.
If it does break it will probably be a split in one of the beams and that side will sink down a couple inches.
The folks on this site tend to over engineer bridges, some because they live in flood prone areas that require it, and others because it is easy to spend somebody else's money.

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[farmer2009]

guys I'm really impressed by and appreciative of your ideas; some of them are pretty neat. Seems to me a wood bridge is a high maintenance item, but then most of us like them. Well, TxDon has taken that to another level...:thumbsup: I think the culvert pipe makes the most sense. I don't have a backhoe; though boy what an excuse to go rent one of those little mini excavators. When we get one of our common three inch rains here, that ditch for sure runs water, but it has been dry here for over a week other than showers. The ditch bottom felt firm under my feet. The farmer's field ditch coming into it is much bigger, and has been dug deeper for sure, so there is a potentially large amount of water that could flow through here. The bridge would be a choke point so whatever I do it has to be a big pipe. And I know absolutely zero about culvert pipe, but I sure am going to learn. It would be nice to have this be attractive as well as functional. For now I want to get to the other side and this winter go logging in the woods back there, clearing a path to that pond that is totally hidden in the middle of twelve acres. If it does turn out nice back there, so folks might want to walk back there and sit by the pond, well, yeah, then I might like to have a pretty bridge to go over.

How wide and deep is he ditch? How full does it get(even if it is only once a year?) The plastic double walled culverts are smooth inside and will carry more water than a corrugated pipe of the same size. If it's wider than deep you could end up needing two side by side. Either way you want to set it up so water doesn't run over the culverts. You want it to run around and fan out if it's more than they can handle. This will save your culverts if they become choked up or just can't handle the water. By letting it fan out it won't start a new ditch. Can you get a dump truck to it. If so get some dirty gravel (has fines). Around here 610's are preferred. This will save a lot of packing gravel. It takes a lot of gravel to install culverts.

 

[farmer2009]

If you want to see how easy culverts are. See Spikers thread titled Recent Flooding here in Rural Living.

 

[radioman]

I seriously dont think its worth repairing. the top looks ok but looks can be decieving. From the pics, those beams and end supports underneath looks scary. You need to find out how deep the rot is, and my guess from the pics is at least 1/3. Just to sister in new beams next to it will be the same about of work to rebuild it but do it right. The bridge looks short enough that rebuilding it in a weekend or two should do it.

If you really dont want to rebuild it, I would at least build a ramp to put on top of bridge and drive tractor on that. I would get 2x12's for driving on and put 2x6's on both sides of 2x12's all nailed (16D) in 6 inches apart in a C shape. Double up on the 2X6's on each side. lay on top of bridge for the tractor to drive on with c facing up so tires are between the 2x6's. That is if the support beams underneath are directly withing the tractor tires. Next use 4 inches screws to screw in the 2x12's into the bridge EACH decking boards so as you drive over it the tension is spilt in half to each deck baords in front and back of tire as you drive across. Using screws allows you to remove the extra support for the horses.