How strong is my wooden bridge?

[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.