[Trippy]

Hello all, i'm looking for other opinions/clarification on a rebuild of our covered bridge ( I-beam ) selection.
calculations for the new beams based off a friend of a friend .
Our bridge is a timber frame style bridge, it's In and exit height is 8ft with bumper hangers set at 7' 6 inches ( cars and light truck only )
although the bridge has gone though many faces, the steal box beams were never replaced and as of now are completely rusted through.
the bridge is closed to traffic atm. ( originally build back in 1976 ).
measurements:
bridge length - 20ft
bridge width - 16ft
plank style rough timber - sub floor 4" h x 8"w x 16ft L planks.

this bridge does span a waterway and we are in the process of pulling a GP-11 permit through DEP.
we are simply removing timber frame and old beams ( 4 old rusted box beams ).

new beams calculated for our bridge are 4 beams @ 12 x 26 WF beams at 20ft length.
the open clearance for the bridge is 19ft.
so my question is, are these beams adequate or should i get different size?
as a side note we are not changing the concrete walls on each end . setting new beams in the 4 old pockets . ( hence us using 4 beams )
we are basically replacing old with new and building it the same as is now.

listing of original bridge - 38-07-A
current bridge that was hit by pick-up truck with trailer.

[Wrat]

Sure, you'll be fine.

Well, unless you're not.

I'm not trying to be a jerk, it's just that you've got a lot of variables involved and precious little to go on.
Will it stand up? Uh... stand up to what? A 1 ton truck at max gross weight? At 30 mph? See what i mean? Lots of variables.
From where I sit, there are two ways to approach this.
1. Restore what was there. Take out the old and put in the new. You'll achieve equivalent strength Whatever it was before, you'll have again.
2. Decide what you want and take a few hundred dollars and talk to a legit Engineer in your area. They can not only make some calcs (no biggie) but can also help you comply with any codes or various gotchas (biggie).
Wrat

[Trippy]

Thanks Wrat, i tried to narrow the basics down as much as i thought necessary for the answer i needed, all variables aside:
(4) I-beams at 20ft lengths
spaced 4 ft apart
uniform load across 20ft length ( 4' x 8' wide timbers for sub floor ) 1/4 inch spacing.
12 WF 26 . i beams ..
needed to find total dead weight capacity of entire surface area?
i can always narrow down variables after i get that answer.



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