Wood on Concrete Bridge Deck

[bob96]

Have a residential bridge where wood timbers are to be the finish flooring/decking. The structure of the deck is steel beams supporting a concrete on metal deck. As far as the wood timbers are there any recommendations for longevity of the timbers. Probably want to put spacers (composite material) between concrete and timbers to prevent rain water from collecting at base of timbers. Any other recommendations?

 

[msquared48]

Definitely treated, including the spacers.

I would put the wood in the traveled way, as they are a wear strip and expendable. I would also place them parallel to the direction of travel, encouraging people to drive there and not elsewhere on the span.

Mike McCann
MMC Engineering
Motto: KISS
Motivation: Don't ask

 

[beton1]

Slope or drains, some means to let water escape.

 

[MikeHalloran]

Timbers can last hundreds of years if kept dry, as in under the concrete and steel (probably not what you want structurally), or under a good roof as in a covered bridge.

Putting the wood on top of the concrete just makes it sacrificial. Even the splash from rain is eventually going to get the wood, spacer or no.

If you're just using the wood as a cushiony deck, that mission might be better served by that saggy recycled plastic pseudo- lumber decking stuff.



Mike Halloran
Pembroke Pines, FL, USA

 

[PEinc]

Longitudinal timbers are quieter than transverse timbers.

http://www.PeirceEngineering.com

 

[bob96]

Thank you all for the informative replies. The timbers are only an architectural feature (i.e. a historic look). The structural deck will be sloped and spacers will be utilized. Any thoughts on attaching the timbers to the concrete deck? This is residential so probably 10-20 cars a day vehicle travel.

 

[Bobber1]

I built a similar small bridge with timber decking on concrete. I put pieces of asphalt roofing shingles, granular side down, between the wood and the concrete. There was no rot of the wood at these contact point after 10 years in Seattle.

Bob G.