Bridges

[Rich]

Hello,

To get my firewood out this year, I need to go across a small seasonal watercourse, yes I suppose that's a steam! I did apply for a wig to cover the cost of a culvert, but when I priced it, what the FC offered didn't even come close to the cost. Anyway I thought I'd use some chestnut to traverse the stream, and am about to fell a couple of trees. I'm planning on cutting these to 4m lengths, a metre of each will be on hardcore/concrete pad on each bank and about 2m spanning the stream. I was then going to cut a dozen or so smaller logs say 2.6m to make the bridge between the 2 transversing poles.

So if you're with me so far... just wondering what sort of diameter logs I should cut for the main 4m traverse and for that matter the shorter poles ? I have been accused of over engineering things in the past so I'm quite keen on not cutting anything too big especially as the trees I have my eyes on are about 200metres away. All I need to get across is my land rover and a trailer full of logs, only one of these will be on the span part of the bridge at any one time and I guess the heavier will be the land rover, maybe 2000kg?

Any guesstimates greatly appreciated.

Cheers

Rich

[Dennis]

Have you looked at the footbridge on Mike and Tracy's blog? It uses principles similar to your proposal. Perhaps you can scale it up to your load-bearing requirements with more logs spanning the stream.

[RichardKing]

If you type in "building log bridges" into Google you get a shed load of info Including

.

http://www.forestresources.org/app/bulletin_pdfs/04-R-14.pdf

.

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

.

One includes a photo of a pickup truck being driven over.

[Kentish Man]

http://handbooks.btcv.org.uk/handbooks/content/section/3782 has some good info on log sizes and building designs... I don't know why, but I always seem to be recommending their site on here! You'll probably need to look at the sleeper bridges section on that page. Good luck!

[Rich]

Thanks for the info, some good material there and yeah I find that BTCV online book invaluable, never thought to look for log sizes in there though. It seems to have been the basis for every other project I've undertaken over the winter, I feel I really ought to buy the book!

Rich

[James M]

Rich - here are some photos of mine, I had a similar problem.

http://www.theloneforester.com/forum/showthread.php?13-Log-Bridge&p=25#post25

[Rich]

Nice bridge James!

I thought I would only use two traversing supports, I would imagine it being a bit easier to level? Thought I'd space them just a little wider than the width between my wheels.

cheers

Rich

[wood troll]

Hi Rich,

Have you thought of dropping a pile of logs into the stream for the time of use? You can then recover them once your firewood has been dragged out. It has the advantage that you don't have to use your best chestnut!

[Rich]

No I'd not really thought of dropping a pile of logs into the stream, but those who know me are anticipating such an occurance, despite.......... well actually because of my best laid plans!

Rich

[John H]

If I was going to drive a vehicle over it I think I would want to have a couple of rsj beams to take the load.

Here is one I made for a customer. It has two pieces of steel channel rolled to form the curve.

http://picasaweb.google.com/lh/photo/QVty1m0JhjdFwaCTFbpMYbZ5UzXoNMxgPHFEwKZAMJs?feat=directlink