That was not a bridge. That was the equivalent of the 1X6 board I pushed across the stream at age 7 when I was hoping to not get my feet wet. (all of me got wet).
That bridge was obviously not designed and built by Nat Taggart, (or even by Dagny Taggart and Hank Rearden).
Looks more like something Jim Taggart and Wesley Mouch would design with the primary intent of ripping off the taxpayers.