Ordinary, Once

Now, plate-girder highway bridges are so common that we don’t even think to comment on them They are simply part of the background of our lives. Truss bridges used to occupy that position.

I took the picture above of the 1904 New Hope–Lambertville Bridge in 2015. It’s a six-span through Pratt truss, carrying a local road. It is, honestly, as ordinary as a truss bridge can be. Here’s a semi-close-up:

The paired flat-bar diagonals are the main tension bracing members; the bar counter-diagonals are to deal with tension in oddball loading configurations. The modern deck, sign, and guardrail look a bit odd with the old bridge, but they help keep it in use. The seagull has a nice view of the pinned upper-chord connection, the portal cross-deck wind-bracing, and the top-chord-to-top-chord diagonal wind bracing.