small bridge

[farstar]

I plan on building a small bridge over a 12'+ stream I was thinking about constructing (2) 2x6x22 with bridging every 24" and 3/4" decking board its just for one person to cross over.
I will have compact crust granite and concrete for connectoon each end . Can anyone comfirm this will work? TY

 

[nehog]

Personally I don't think a 2x6 (two of them) would be strong enough. You can't say 'one' person, unless you have a way to absolutely enforce it because otherwise the moment your back is turned, two heavy people will cross together.

 

[p_mori7]

12+ ? Exactly how much is "+" ?

I would fell a couple of trees, then put 2x6 planking over them.

 

[Zippercat]

Check the tables here:

http://www.wclib.org/pdfs/simpspantbls.pdf

 

[Kevin54]

Farstar....welcome to Garage Journal!!!! If you would, could you put the state that you live in, into your profile? It always helps to answer questions. Plus you more than likely have some Garage Journal neighbors close by. It always comes in handy if you may need some help

With that given, could you post up a pic of where you are wanting to build the bridge? Myself, I would want to go larger than a 2x6" on each side covered with decking. At 22', your 2x6 will want to bow. I would go at least a 2x10" if not a 2"x12". Do you have an idea as to how deep the creek gets, and how deep it is now? You will want some support as close as you can get to the creeks edge on each side. I would probably use 6"x6" post on each side down about 4' into the ground. I'd then keep the bridge up far enough that you wouldn't have to worry about any possible flooding. Keep the bridge level, and also make the bridge wide enough for a couple people, or even wide enough that if you had to drive a quad over it your could.

Something like this:

 

[rsanter]

My dad has a walking bridge leading to his house
The ends are concrete poured with a shelf formed in
The span is about 10 feet and it was made with 3 6x8s and then 2x6s across the top of them for planks
This bridge has been in place for over 30years

Bob

 

[Leaflessshadetree]

At the minimum I'd run 3 2x10s (each side and down the middle) across the span. About 4 ft spacing for bridging. Deck boards for the walking surface. Keep it above high water level. Only weather proof materials.
Visit a golf course (most around here have at least one bridge) to get some ideas.

 

[Kevin54]

At the minimum I'd run 3 2x10s (each side and down the middle) across the span. About 4 ft spacing for bridging. Deck boards for the walking surface. Keep it above high water level. Only weather proof materials.
Visit a golf course (most around here have at least one bridge) to get some ideas.

^^^^THIS^^^^

Also, in building it, if there is an excessive bit of slope going up and coming off of the bridge, you can always add some grip tape to it. One thing about treated lumber, before it get a little age to it, it is slippery as snot. Always make something safer than it should be.

 

[tadg]

I built a bridge over a 14 foot wide almost 15 foot deep ditch that crosses my back yard. My father was a civil engineer who specialized in bridges, so I sought his expert help on this task. I have a small tractor, so it was sized for a 1000lb load in the center of the bridge.

What he selected was 4 2x10 boards, 20 foot long, with 2 sistered together on each side with 2x10 cross pieces every 4 feet. This got decked with 2 x 6's and the railings used 4x4's bolted to the sides.

I built the frame with only 1 2x10 per side to minimize the weight, then winched it across the void and added the 2nd 2x10s and decking once it was in place.

So far it has been great, it doesn't wiggle at all even with a half dozen people on it. The only annoyance has been that the county made me replace the railing with one that is much uglier and that can't be climbed by children.

Tad