Bit disappointing, slightly similar to this one in Wyandotte Co., this is no more than a pipe-hanger bridge https://bridgehunter.com/ks/wyandotte/bh45080/ . Although there are signs of a timber bridge being in this spot at one time, currently there is only the pipe/garbage dam. Possible there is a low-water paved crossing under the muck which may have been visible at one time via satellite
Good catch. I suspect that this is a plate girder, but I don't know for sure.
The 1951 topo shows a rail spur running north from here to join the MoPac line running along the river.
After a careful review of aerial imagery, I still can't tell for sure what we have here. It appears to be roughly 50 - 60 feet in length, although it could be as long as 70 feet, depending on how much of it is hiding in the trees.
This one is a true mystery. There is an old bridge of some sort over Fivemile Creek. It may be plate girder, slab, or perhaps a small pony truss.
Thanks for trudging out there. It looked pretty neat from aerial imagery.