View toward North Side
Elevation drawing looking downstream
More detail photos
Robert Clemente Bridge
Sixth Street Bridge
USGS 7.5" Topo Quad - UTM Coordinates:
Pittsburgh West - Zone 17; 0584 4477
-- Federal St on right descending bank of Allegheny River
-- Sixth St and Fort Duquesne Blvd on left descending bank of Allegheny River
-- Allegheny River at mile 0.5; Tenth Street Bypass
TYPE OF CONSTRUCTION / DESIGN:
cables are steel eyebar chain
steel eyebar suspenders
steel plate girder deck
rusticated ashlar piers
LENGTH OF MAIN SPAN:
442 ft (410 ft clear span)
TOTAL LENGTH (including longest elevated ramp):
HEIGHT OF DECK:
Emsworth Dam normal pool level 710 ft
YEAR ERECTED / ENGINEER:
1925-28, County of Allegheny
Vernon R. Covell, T.J. Wilkerson, A.D. Nutter, and H.E. Dodge of the Allegheny County Department of Public Works, engineers; Stanley L. Roush, architect
Allegheny County, current owner
One of the "Three Sisters." Municipal Art Commission mandated suspension as form of the bridges, but site conditions did not allow for typical anchorages. Bridges were built as cantilevers until catenaries were completed.
In a very unusual, self-anchored suspension design, instead of heavy anchorages to hold the cable ends, rigid towers hold the ends apart. First of this type in US. Fourth bridge built on this site.
Deck girders were previously painted green and remaining superstructure was painted aluminum grey. Most downtown Pittsburgh river bridges are currently painted golden yellow (the official city colors are Black and Gold).
Won an award for beauty from American Institute of Steel Contruction in 1929.
The first bridge (1819) to cross the Allegheny River and the first of four which would connect Federal St to Sixth St was a Burr arch-truss. The second bridge (1857-1892) was a wire rope suspension bridge by John Roebling, creator of the Brooklyn Bridge in New York City and the second bridge at Smithfield Street in Pittsburgh.
The 1892 Sixth Street Bridge (a pair of Pratt trusses and the third bridge built in this location) was floated to a new location over the Ohio River back channel between Coraopolis and Neville Island in 1927 to make way for the current structure. That structure was replaced by a deck girder bridge which was completed in 1995.
Sixth St was formerly St. Clair St in Pittsburgh; it aligns with Federal St in the former city of Allegheny (Northside).
Field Notes provide additional technical information.
view page - "Three Sisters" Bridges -- Historic American Engineering Record document
Comm. of PA, et. al.: "Historic Hwy Bridges"; Kidney: "Landmark Architecture"; USACE Allegheny River Nav. Charts
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