This is perhaps my favorite bridge in the USA. If any bridge enthusiast has not seen it, put it on your bucket list to take a walk across. The engineering attributes and fabrication details are wonderful.
A nice little write-up on the Smithfield Street Bridge:
I know about Smithfield Street Bridge. it is very old bridge. it is over 125 years old. wow It is good.
I just learned that the Smithfield Street Bridge, a double lenticular truss design, is known to old time Pittsburghers as the "kissing fish bridge". For more on Pittsburgh bridges, see "The Bridges of Pittsburgh" by Bob Regan with photos by Tim Fabian published in June 2006 by The Local History Company. (Full disclosure: I'm one of the publishers!)