A doctor customer is wanting me to build a bridge over a decent sized creek about 40' wide and 8-10' deep for his hunting land. He wants to cross on ATV's and maybe a small tractor (80hp). As a liability concern considering I am not a bridge engineer, a 53' arch deck flat bed semi trailer frame seems to be the best idea I have. It should have carrying capacity, is already structurally braced, reinforced and floored. Any thoughts on the viability of this? And, where in northeast Texas (Sulphur Springs area) might I find such a frame that is beyond roadworthy but functional for this re-purpose?
railroad flat car is the other option. For a mid size tractor you could just get some beams from a steel supplier and run some timbers sideways across them
put in a culvert
What, and offend the water gods. Probably end up in court for 10 years. Lots of old semi trailers used for smaller creeks around here. Just put a (cover your butt) load limit sign on it at both ends.
Flat roof steel trusses
I have seen loaded (84,000 lb) tractor trailers running over 2 side by side trailers.
I did just that here at my home. I have a stream my driveway crosses, it's a span of 19'. I investigated a number of options and found a local trucking company that had pulled a 40' flatbed from service for a cracked frame at the 5th wheel plate. It was given to me, I cut it in half and expanded the portion that was necked down for the 5th wheel and laid the two pieces side by side for a deck that is now 15' wide. Bolted some guard rail to the sides and it's served me for over 25 years. I've had a 110,000lb crane cross, concrete mixers loaded with 11 yards of concrete and numerous tri-axle dumps loaded with 25 yards of material. I poured concrete abutments for it to sit on. I'm not a fan of culverts. Before I built my bridge I witnessed two neighbors have their driveways wash out because debris clogged the pipes during floods. One neighbor had it happen twice before he built his own bridge. And my next door neighbor has had his culvert wash out once since I've had my bridge up.
Washout is also my holdout on a culvert. Hydraulic action will take one out in no time with the best of guarding. Thanks for all the positive responses to the idea. Bad thing is, I was stopped by one flowing creek thinking it was the main channel to get across. I talked to the owner today and come to find out, there is an even larger creek that I didn't get to. Will take a trip and see it this weekend. The railroad flatcar seems like a great idea for it, but I would have no idea where to look for one or the logistics of getting it moved and into place. A clear span I beam bridge would be better, but I think some engineering would need to be involved. He's a tightly wound city slicker and I'm just a mechanic and small time operator who he's come to depend on for more questions and ideas than I have answers to or resources for.
If I was going with the flat bed idea, I'd have a 2' x 4' x 12' footer on both sides, and pin the bed to it. I'd also add some R-4 scour protection.
I don't recall where I 've seen it but there's an outfit that advertises and sells the railroad flatcars, they're overwide to haul but they haul them upside down on a 48 foot flatbed or lowboy I think, there's different lengths.
Found this. Any help? regards d.d. http://www.sterlingrail.com/classifieds/classified.php?id=12837
Good hit, same publication, more options: http://www.sterlingrail.com/classifieds/Listings.php?type=Flat Car Bridges&fsw=FS
Wow. Thanks! I will pitch these at him after looking at the main channel. Had no idea they were up to 90' long. Making them into a trailer makes them relatively easy to move also.
is there a bridge building company near you? there is 1 just up the road from my shop & he will sell the old beams out of state bridges that they tear out & sell the decking material to put on it so you can have a bridge as good as a state/county bridge just a thought
Finally got to look at both channels which the owner wants to cross. I measured today and from bank edge to edge in a straight area to avoid erosion and undercut, it measures 36 feet. Is this narrow enough for a 50' arch deck to work on? I would have 8' of over reach to work with on each side. Also, there is no way to get a concrete truck in to the sites so footings are an issue. I was thinking about possibly using some larger railroad timbers (bridge frame I assume) to set them on.
Could you dig down and stack mafia blocks for the footing?
Similar to trailer house mounting blocks? Yes. Excavation won't be a problem, just what to put in the hole.
I think he is referring to what we call bunker blocks, or stack and stagger blocks. They are normally 2' x 2' x 4' concrete blocks. They make good bridge footings.
They are pictured in this post: HeavyEquipmentForums
I've used blocks like that as bridge head walls before and it has worked perfectly, the bridge hasn't had any issues and it's been 6 years or so. We just waited till the middle of summer to do it when the water level was at its lowest point then set the first block lower than the bed of the stream and just stacked em up to the height we needed.