Orthotropic Deck

Briefly, an orthotropic deck consists of solid steel plates supported by ribs underneath.

From Wikipedia: https://en.wikipedia.org/wiki/Orthotropic_deck

An orthotropic bridge or orthotropic deck is one whose deck typically comprises a structural steel deck plate stiffened either longitudinally or transversely, or in both directions. This allows the deck both to directly bear vehicular loads and to contribute to the bridge structure's overall load-bearing behavior.

E.L. Patton Yukon River Bridge (Yukon-Koyukuk Census Area, Alaska)
Built 1975
Bridge over Yukon River on Dalton Highway
Open to traffic

Pekin Bridge (Tazewell County, Illinois)
Built 1982 to replace a lift-type bridge at the same location
Bridge over Illinois River on Illinois Route 9 in Pekin
Open to traffic