The Breakroom > The Water Cooler
Building a Bridge
vtsteam:
--- Quote from: awemawson on August 16, 2018, 01:19:20 PM ---a bit slippery in the wet I'd assume Steve :scratch:
--- End quote ---
Nope. Many town road wooden decked bridges here.
To lighten your dour anticipations, Andrew, don't forget embedded road grit. Or the fact that bridges are always level. And driveway speeds necessarily low, at least here.
ps. Concrete and blacktop are slippery in snow. This is Vermont.
Eight months of winter, and four months of damn poor sledding!
vtsteam:
John, thanks! :beer:
The 6 blocks left will be placed at either end of the bridge as abutments (mentioned above). Then gravel fill goes behind them.
They are 21" tall, which will be the height of the bridge deck plus the runner strips, yet to be added
Steel beams are 12" tall, wooden deck is 5-1/2" tall, and runner strips are 3-1/2" tall (and 40" wide), total 21" tall.
Beams are wide flange W12X26 meaning 12" tall, 26 lbs/ft weight. Fortuitously, they had mfr stickers on them when they arrived, and those showed ASTM A992 steel instead of the A-36 steel I thought they would be. That means they are stronger than I thought.
A-36 is 36,000 psi yield. A992 is 50,000 psi yield.
awemawson:
Steve, we have a wooden decked bridge crossing a small stream by our back door. It's ten foot wide and spans maybe twenty feet. Formed on a pair of heavy RSJ's that I had curved slightly (12 inch rise in the middle) for added strength and aesthetics. It's rated for four tons.
The deck is made from oak railway 'crossing sleepers' as ordinary sleepers (ties, USA speak?) weren't long enough. At certain times of the year you cannot walk over it without holding the hand rail, as even that slight arch has you skidding a over t .
It's probably a reflection on our different climates. External woodwork can suffer very badly from mosses and microscopic slimes.
Here is a picture of it being decked out for my youngest daughters wedding, interrupted by the Emu incident !
PekkaNF:
Seen that in UK!. Beautiful pier or bridge covered with ugly metal net, after one person plunges into pond.
Pekka
vtsteam:
Mosses and slimes would mean little or no vehicular traffic -- Yours seems to be a footbridge, I see flower vases on yours. and a 1 in 10 incline (1 foot at center, 20; long) is not a minor slope. No dirt road lead-ins to add grit.
As I said there are many wooden surfaced town road bridges here in regular use. And our wooden covered bridges are famous. We have a large network of dirt roads here. I think problems may arise when people pave up to older wooden bridges. It may also be that the wood chosen has something to do with it. Softwoods absorb grit and fray differently than hardwoods.
Anyway, tired of this kind of discussion with you, Andrew, like Rob, which is why I do wonder why I post projects at all sometimes.
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