Timber Bridges

I have a lot of questions about timber bridges that I hope folks would be kind enough to answer. I own some property in northern Ontario that I hope to build a home on; however, I need a bridge to span a 30 foot ravine. It would need to accomodate construction traffic initally and then personal vehicle traffic afterwards. I like the idea of timber to be in keeping with the natural setting. Where do you begin? Who does this type of construction in my area? What's the rough order of magnitude for cost? I know the real answer is "It depends...", but I'm trying to gage how realistic this is given my budget. Any help would be appreciated.

Thirty feet is easily spannable with the simpler trusses, so cost needn't be extreme, this of course, needs be measured against your expectations and how realistic they are.

You have three options ---

Treated trusswork & deck open to the weather(potentially prohibited over a waterway) & [unplesant,unhealthy to cut and therefore more expensive to join]

Boarded in "Pony" trusses. Once common but no longer the image that comes to mind when thinking timber bridge ( best planned with a treated deck)

A traditional covered span (adding the expense of a roof system & roofng, but eliminating the need for treated lumber > except for the bed timbers, yet still no leaching < nor will fireproofing treatments be weatherworn)

--- You must add to the cost of the bridge ---

It's abutments (though if spanning a true ravine, bedrock should ~?~ be at or near grade, again minimizing cost)

Local Engineering requirements.

Good luck in your research.

The National Wood in Transportation Program is just the thing for you. Take a look at: http://www.fs.fed.us/na/wit/

You should be able to obtain (free of additional charge -- your tax dollars already paid for it) standard sets of construction plans for wooden bridges of various types and spans. One or more might be adaptable to your situation. Good luck.