With a recorded date of 1920, this bridge is a well-executed use of reused bridge parts. This bridge, built slightly skewed, is a King post truss, which is basically a Pratt truss with only 2 panels. The King post and Queen post (3 panel full-slope Pratt truss) are amongst the oldest types of truss bridge.
At first glance, this bridge, with it center tie rods, appears to be a rare, perhaps pin-connected King Post Truss.
However, this bridge is a combination riveted and welded truss bridge! The photo below shows the connection between the two inclined endposts. The quality of the welds is very good, and the lacing terminates at the top end with a wide tie plate, as is standard practice.
Below, a view of the same connection on the opposite side of the bridge. Note the cut rivets.
Below, another view of this connection. I don't know if the rods & nuts are threaded or not, but they are welded.
Below, connection of the rods to the lower chord. The rods pass through the lower chord and connect to the floor beam. The lower chord is made up of upper chord/endpost type built-up section recycled from demolished bridges. Note the wooden stringer.
below, detail of connection of endpost and lower chord. The lower chord appears to have been recycled from a pin-connected bridge. In its present form, this connection is welded.
Below, a view of the opposite end.
Below, view of the lower end of the inclined endpost. The close rivet spacing indicates this was the design end of this member, so care was taken in designing this bridge to use truss bridge members "correctly".
Below, another view of the span. I had read about this bridge in the 1993 book Spans of Time by J. E. King, and from the picture and date given, figured it was a pin-connected bridge, so I was slightly disappointed to see it was a "home-made" structure. But compared to this bridge in Payne County, it is a well-executed study in building a small pony truss. This bridge services a dead-end road, so I expect it to be around for some time to come. A "real" pin-connected King Truss pony span does exist in Tulsa county. however.
