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Logging bridge

Started by woodroe, September 17, 2010, 06:53:52 AM

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woodroe

Hey eveyone,
newbie here
Question :

Put a 24' bridge across a small stream on the back 20 about 8 years ago using peeled pine logs. 2 good size logs each side with center support.

Decked it with untreated hemlock 2x8s which have since deteriorated and need replacing.

When stripping the 2x8s noticed some surface rot in the logs where the planks were placed.

Heres the question: Would it buy the logs any time to roll them over before re planking the bridge ?

I knew this wouldn't last forever when i put it in but if i could get another
8 years out of it  that would be good.

Using an old 2 lunger JD tractor weighing about 1 1/2 tons for firewood and occasional
small logging operation.

Thanks for your input
 
Skidding firewood with a kubota L3300.

Kevin

I use tar paper on the beams prior to setting the deck.
It saves them from any water that sits on the beams between the decking.

isawlogs


With out a picture of the detoriation, I am betting that its the sap wood that has rotted in those pine logs you used. I would scratch that off with a chain saw and look how sound the wood is below it.
  Would be nice to get a pic of the bridge  ;)
A man does not always grow wise as he grows old , but he always grows old as he grows wise .

   Marcel

DanG

I would definitely be checking those logs for soundness before redecking it.
"I don't feel like an old man.  I feel like a young man who has something wrong with him."  Dick Cavett
"Beat not thy sword into a plowshare, rather beat the sword of thine enemy into a plowshare."

Chuck White

Eight years is a long time for a Pine log to be on "ground contact"!

Check and make sure there's not too much rot as others have mentioned.  Check the ends too!
~Chuck~  Cooks Cat Claw sharpener and single tooth setter.  2018 Chevy Silverado and 2021 Subaru Ascent.
With basic mechanical skills and the ability to read you can maintain a Woodmizer  LT40!

woodroe

appreciate the comments
If i can figure out the photo section here I'll take a pic and post it.
Like the roofing paper idea to keep the water off the logs.
Meanwhile I'll take a closer look at the logs, see how far the rot has penetrated.
If the rot isn't too bad, no more than a couple inches deep, would turning the rotted side down stop it from rotting more ??? Or not ???
thousand dollar question i know.
Skidding firewood with a kubota L3300.

northwoods1

I think the tar paper is a good idea or better yet what I have done in a similar situation is to just use  shingles. A few on the deck of the bridge wouldn't hurt they make it easier and safer to walk across if its slippery.

John Mc

Are the ends of your pine logs up off the ground, or are they laying in contact with the soil?

Hard to say without seeing what you have now.  I don't know what the odds are of you getting another 8 years out of the existing pine logs, especially if they are already showing signs of rot.

If it were me, and I were going to the trouble of re-decking it, I'd put something more rot-resistant in than the peeled pine. Then if my deck died 8 years from now, I might be more comfortable re-using whatever rot-resistant wood I had used in this repair effort. Otherwise, you may be faced with tearing of your decking a few years down the road, replacing the beams, and deciding whether to put new decking on, or re-use the decking that has now lost half it's life...

John Mc
If the only tool you have is a hammer, you tend to see every problem as a nail.   - Abraham Maslow

beenthere

Welcome to the forum. 
I too would be suspect of the pine.

But if the bottom is still sound, I wouldn't turn them over. The lower side is in tension and turning the logs just puts the rotted side in tension. Less overall strength of the same logs as beams.

When will you know that the bridge won't hold your 2 lunger going across anymore?
When it doesn't ?? -- or the time just before it doesn't?

Inspecting wood for advanced decay is not so difficult, but inspecting wood for early (non-visible) strength-reducing decay is more difficult.            Not impossible with sounding equipment that measures the attenuation of sound signals passing through the wood, but requires special equipment and trained technician.

south central Wisconsin
It may be that my sole purpose in life is simply to serve as a warning to others

woodroe

The log ends were kept  out of contact with the ground by laying them on plywood strips , maybe slightly better than directly on the ground.
However, took a real good look at the logs a few minutes ago and remembered that two of those logs were Balsam fir and those two are real punky.
The two pine logs are still in decent shape but I'm going to shut it down to tractor use and keep it for snowmobile use.
Maybe rebuild it when the Pine stand back there comes into maturity 5-10 yrs from now.
Recommend to me some rot resistant wood stringers for the next bridge.....
One thing about the pine is its free and handy.
Thanks for all the great advice !
Skidding firewood with a kubota L3300.

Autocar

Over the years I always considered building a portable bridge and winching it across or dragging it over. Then about twenty or so years ago I crossed a small creek and the next thing I new water was running in one door and out the other,the scary thing about it all was there was only about ten inches of water in the creek. It was a old crossing a farmer had put in with feild stone looked pretty good to me. I still wake up at night to this day in a cold sweat  :D Well maybe thats stretching it some but to this day I will walk away from jobs with steep creek crossing. I thought for a while the skidder was there for ever. The crazy thing about it there was a landfill across the river from me so I drove over there and told the operator, he was operating a big dozer with a loader bucket on it. He drives back there across a good river crossing and over to the creek I was in and we took a few chains and literally lifted it up and he backed up and set it on dry land. Thats probably the closest I ever came to kissing a man ! ;D
Bill

John Mc

Quote from: woodroe on September 17, 2010, 01:38:41 PM
Recommend to me some rot resistant wood stringers for the next bridge.....
One thing about the pine is its free and handy.

Hemlock is pretty good, if you strip the bark
Tamarack/ Larch is also good
Cedar is pretty rot resistant, but I don't know how strong it is.

I've got a couple of hemlock logs I use for a crossing over a seasonal stream on my property. I more or less squared them up freehand with a chainsaw. They're holding up very well after a few years of use. I put the ends up on top of a shorter sections of hemlock laid crossways (like a railroad tie). My thinking was that these short ones in ground contact might rot out more quickly, but if so I can just pick up the end, pull them out, and slip new ones in.  If I get the time and motivation, I might replace those shorter hemlocks on the ground with some large rocks... don't have to worry about those rotting, but it takes a bit more effort to get them set right.
If the only tool you have is a hammer, you tend to see every problem as a nail.   - Abraham Maslow

woodroe

I know i won't use fir again, but they were handy at the time, almost fell right where they wanted to be  ;D
I think hemlock would be a decent wood, strong. Have some handy too. Stuff is dang heavy though.
Minn. extension put out a decent article about temp. logging bridges similar to what i had and most smaller type logging operations might use for stream crossings.

They recommend Pine or Oak for stringers.
Use what you have i guess....

http://www.extension.umn.edu/distribution/naturalresources/dd7005.html








Skidding firewood with a kubota L3300.

bill m

Hemlock would be a very good choice. Make sure to peel off all of the bark first. You might be able to find some old railroad ties to set the ends on. It would make construction easier and the logs would last a lot longer.
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