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.

Sent from my iPhone using TractorByNet

 

[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.

 

[EddieWalker]

The bridge is toast. I would spend a dime on it. It does have a nice look to it and you might want to keep it as a walking bridge, but I wouldn't drive anything over it.

Figure out how big of a culvert you will need and never have to worry about it again. Go with ribbed on the outside plastic and smooth wall on the inside. A 24 inch culvert will handle a lot of water. Pour concrete or stack 60 pound sacks of it with rebar through the sacks at the entrance and exit of the pipe so water doesn't erode the sides of it and you'll be good for the rest of your life.

Eddie

 

[MacLawn]

Well daug, I'm going to be the odd man here. I'd have already driven over that bridge. Like suggested, I'd crawl under poking screwdriver in a few spots to test, and if only a bit of surface rot, I'd be over that thing with me tractor. Those beams look like locust to me. VERY strong wood, and lasts about forever. That peeling off look is not rot. Just the way locust does. I'd drive over that.

Having said the above, as I had time, yes, I would either reinforce it, or use a big culvert. The black plastic culverts have a green stripe - the stripe goes UP! It's the way they're designed. Again, after a good check, hey, I'd be over that bridge in a NYC second.

 

[daugen]

well I got motivated and just went out and this time crawled totally under the bridge.
Glad I did.
Good news and bad news.
Bad news is outside of several beams and cross footers definitely rotten, termites, who knows.
Good news is the beams under there are serious, almost a foot wide and at least six to eight inches thick. Big structural stuff, not anything at Lowes for sure. Screwdriver went in on the outside, but not on the inside.

But no question, lot of rot, but Mac, it might do it...
but that creek bed now looks a bit deeper.
So, this bridge was built for more than horses. But maybe not 57 of them...

 

[Dr_Zinj]

Those beams look like 12x12s to me. If they were intact, they'd handle the tractor just fine, provided the wheels were positioned over them. If the wheels are running on the boards but not over the beams, you might break through. And if the beams are Swiss cheese, then they could break just walking over them. 1 or 2 foot drop shouldn't be a problem if the bridge just breaks in two, just drive over it. However, if it powders or splinters under you that might be a problem if the drop is too great or the sides of the stream are too steep.

I'm building a 2 span bridge over a seasonal stream on my property. Each span is 10 to 12 foot across. 2 main support beams made of tree trunks (treated) trimmed to about 12 inches and positioned to match wheel base of my tractor. Covered with 2x12s for the decking and 2x12's for the wheel surface the length of the bridge. About 2 to 3 foot drop under the bridge.

 

[daugen]

note in the second picture the right bank/side of the bridge had been repaired, probably when they put the new decking on, and they put lumber in there, almost looks wrapped in material like firehose. and look how badly rotted that big beam is there too...the part over the bank.

not 12x12 but I'm guessing 8x12. I would think four of them, in good condition, with proper planking, would carry quite a bit of weight.

next time I crawl under there I'll take a tape and do the measurements; i.e. how far apart the inner two beams are and if they might, by luck, line up. No matter what, with all that rot, unless I took core drillings of the things, would be hard for me to trust them.

I want to add to the "poking" info. On the sides of the beams, in some spots, went in an inch or two. In the center of the beam from the bottom, rock hard.

 

[bcp]

If it broke with the tractor on it, more likely one side would break (only or first), dumping the tractor upside-down in the ditch.

No guarantee of a gently, even break.

Bruce

 

[MossRoad]

I'd put in a couple culvert pipes, bury it in large rip-rap (think 4" crushed, jagged, rock), and do like suggested above with some stacked concrete sacks and rebar. Also, be sure to have a swale, or low spot for any high water to go around the bridge should it start to top the brigde. They do that on dams for an emergency spillway. Think 100 year rain.

 

[daugen]

If it broke with the tractor on it, more likely one side would break (only or first), dumping the tractor upside-down in the ditch.

No guarantee of a gently, even break.

Bruce

Thank you Bruce. I'm a retired insurance guy and needless to say, a bit risk averse.
I really don't want to test the ROPS in my tractor.

Ok, but let's make the most of this.
I think I should sell tickets, like the boxers do.
Live camera action on the first run of the Kubota, with FEL and ballast box, over the bridge,
just as it is now. All that rot, ladies and gentlemen, he's risking it all, life and limb, just for you.
All LIVE, unedited for your viewing pleasure.

Now wouldn't that make a Youtube event. Except those that don't know me would of course hope the bridge breaks...
it would be a real crapshoot, in perhaps many versions of the term...

ok, back to reality. A twin tube culvert makes good sense, plug one, another at a lower level continues to flow.
No reason I could not dig this myself this winter, but I'd leave this little bridge alone then and just use it for the UTV and golf cart. Would probably do it on the right side of this bridge and actually, what really needs to be done is having some slavee hand dig the silt and muck out under this existing bridge, because it looks like the water would pool on the left side, water always going left to right.

 

[MossRoad]

The twin culvers would be side by side. You want that water out of there ASAP. Two pipes side by side will drain way faster than one over the other. You don't want anything impeding the flow of the water.

 

[k0ua]

If you want an opinion on culverts I will give you mine. I have 2 culverts side by side, about 30 inches or so each. They are a pain in the "rear" to keep them from stopping up with sticks, then leaves, then mud, etc. and the water backs up , and I have seen it 12 foot deep, and runs over the road and erodes the other side. I had to buy a bunch more fill to go on the downhill side when I neglected to keep the sticks and muck cleaned out. It is at least a yearly job if not more depending on how much rain we have.

I would much rather have one single larger culvert than the twin culverts, as the problem always start with a single stick across the inside edges where they are tangent and goes badly as the stick captures more sticks, then leaves etc. Not to mention the children s floating toys from the housing development upstream.

I had no say in the culvert placing, they were there when I came, but I learned the hard way about the cleaning needed. For me it would be one large culvert.