[quote=TomPenny]theres this guy around here that puts up a lot of steel buildings for home owners. He makes his own trusses out of square tubing and round bar. the round bar is bent in a pattern /\/\/\ and then welded to the square bar. I guess it works haven't seen any problems.
a truss would be a problem for me when high water flows in.[/QUOTE
I've seen RR/flat car bridge before,I would guess someone would make a buisness out of it, It's co$t effective. Bar truss would work(light duty). You could block flow entrance w/sheetmetal mounted from outside ledger-to-bottom of truss(forming smooth top funnel) keeping junk from tangling in bar joist? Or flip-em & use em on top and support on bottom of truss w/ truss acting as hand-rail.(again even more light duty) Bar joist can be had at demo jobs, cheap.(scrap price)(bldg inspectors req. new engineer cert.).bldg permit hard to get using them? w/out new cert.(nobody wants to re-cert,un-seen damage/past in-use stresses unknown ect.)Old mobile home beams good too. You've come up w/lots of good ideas.....loading dock ramps/bar-truss/ect. I'm a scraper i guess
building something VS/ already built w/a/ little mods here&there, seems easier to me? I'm sure you'll come-up w/something.
As to handling float. I seem to remember JD 690? t-hoe. After carrier cut-out,it lighten it up quite a bit. Not to big a t-hoe. Pilings were set/bulk head(metal siding)in place/&back-filled. rigged w/ 4 cables, held close to operator station(good operator)walked into bottom of ditch/ & set into place/welded to iron lagged into piling. done. good luck
