Fishbelly Deck Truss

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Fishbelly deck truss bridges are an exceedingly rare form of deck truss with a distinctive polygonal bottom chord that is parallel to the top chord on all panels except for the last couple panels, where it slopes upward to meet the endpost. The design was usually employed where a substructure was being reused to build a new bridge, but the new bridge needed deeper trusses so it would be stronger. making the truss deeper in the center, but shallower at the ends allowed the substructure to be reused, while also offering the strength of a deeper truss.

Avoca Trail - Mill Creek Bridge (St. Clair County, Michigan)
Fishbelly Pratt deck truss bridge over Mill Creek on Wadhams to Avoca Trail (formerly Pere Marquette RR)
Open to pedestrians only

Buzzi Unicem - LaSalle Rail Bridge (LaSalle County, Illinois)
Built 1896, two deck truss spans removed and replaced with a Parker truss in 1932
Through truss bridge over Illinois River/I&M Canal/Railroad (IAIS) on Buzzi Unicem's private rail line in La Salle

CNTP - New River Viaduct (3rd) (Scott County, Tennessee)
Built 1908; Replaced by a new bridge and mostly removed 1963
Abandoned Pratt deck truss bridge over New River once carried Cincinnati, New Orleans and Texas Pacific Railway's Cincinnati Southern Railroad (later Norfolk Southern), before being bypassed

H&BTM - Cypher Bridge (Bedford County, Pennsylvania)
Built 1937
Abandoned fishbelly Warren deck truss bridge over Raystown Branch Juniata River on former H&BT

MON - Tippecanoe River Bridge (White County, Indiana)
Built ca. 1895, demolished ca. 1986
Lost Deck truss bridge over Tippecanoe River and access roads on former Monon Railroad in Monticello

Morenci Southern - Gila River Bridge (Greenlee County, Arizona)
Built 1902;
Abandoned Fishbelly Pratt deck truss bridge over Gila River on Morenci Southern Railroad

NS - Delaware River Bridge (CNJ) (Northampton County, Pennsylvania)
Fishbelly deck truss bridge over Delaware River on Norfolk Southern Railway
Open to traffic

PGR - Soquel Creek Bridge (Santa Cruz County, California)
Pratt Deck truss bridge over Soquel Creek on Progressive Rail Inc. tracks
Open Railroad only