This structure is the OK 18 bridge over the Arkansas at Ralston, OK. The bridge was built was built in 1938, and stands about 1/4 mile west from the remains of an earlier bridge (scroll down to the last photo). It consists of five 210-foot K-Parker spans and 4 100' Ponies. All the portals and guards are original. The above photo is the bridge from the south, in Pawnee County, from downtown Ralston.
Below, the Osage County end of the bridge.
Above, a side view of one of the main spans. Below, close side view of most of the spans. The piers catch a lot of debris, as can be seen on their upsteam sides.
Above, a deck view and detail of the portal and upper bracing. Bridges from this era have smooth, substantial appearance, and full width roadway decks.
On a recent visit to this bridge, the Arkansas River was sand clogged enough that I could take a side view of the bridge with part of the remains from the earlier bridge in the foreground. In this view, looking west, you can see all five through spans and the lone pier.