Hi Steve,
Trammayo's bridge is very like the Caledonian Railway bridge at Connel Ferry - see the following link
http://canmore.rcahms.gov.uk/en/site/23278/details/connel+ferry+bridge/ < Link To http://canmore.rcahms.gov...s/connel+ferry+bridge/
and
http://www.railbrit.co.uk/location.php?loc=Connel Ferry Bridge < Link To http://www.railbrit.co.uk...onnel%20Ferry%20Bridge
That is a cantilever style as the two supports (1 each end) slope inwards towards each other, and the deck for the bridge is then supported off, and by those cantilevers.
This bridge was a rail bridge and is now a road bridge.
The deck will be a simple construction with a couple of stringers end to end where the rails were, with a couple more I think at the outer edges. Those will be held together by cross girders which could be like a capital 'X', with outriggers for the sides.
My Howe truss bridge has, for strength; underneath it a couple of square steel tubes that are hidden in normal use, then the rest is plastic cut to size.
As others have said, what you have in the photo is a truss bridge (the sides suspended from the higher bits) to ensure that any centre piers are not needed.
Back to Connel Ferry - that is likle that because the river underneath is both fast flowing and has a pinch point that acts like a waterfall: again see the (2nd) link, which explains it, so no piers could be built with safety, and a long life.
ere so i need a help....what does u called them in usa:impatient:? any pictures? names? for my project.
for bottom not top..lol
