Fifth Street Bridge, Spanning MBTA Fitchburg Commuter Rail Line tracks, Conrail Fitchburg Secondary Line & North Nashua River, Fitchburg, Worcester County, MA

Significance: The Fifth Street Bridge is the only reinforced concrete through-arch highway bridge presently known in Massachusetts and one of only eight Massachusetts highway bridges to include open-spandrel concrete deck-arch spans. The bridge's self-supported structural steel arch rib reinforcing (as opposed to the now predominant steel rebar reinforcing) represents an early and rather rare development of the Melan reinforcing system. The bridge also exemplifies some of the technological problems in early reinforced concrete bridge design and construction.
Survey number: HAER MA-143