The Seventh Street Bridge in Pittsburgh Pennsylvania is a Self-anchored suspension bridge which crosses the Allegheny River. Designed by Vernon R. Covell, it was built in 1925-1926 by the American Bridge Company. It is constructed of steel, and uses steel eye-bars in lieu of cables. It is sometimes said to be one of the "Three Sisters" bridges, spanning the Allegheny at 6th, 7th, and 9th streets in downtown.
From the HAER page: http://memory.loc.gov/cgi-bin/ampage?collId=hhdatapage&fileName=pa/pa3800/pa3845/data/hhdatapage.db&recNum=1
(this is the first of 40 some pages on this topic,k could be a good basis for a "three sisters" article)
Ps HISTORIC AMERICAN ENGINEERING RECORD THREE SISTERS BRIDGES (Trinity of Bridges) HAER No. PA-490 Location Spanning Allegheny River at Sixth, Seventh, and Ninth streets, Pittsburgh, Allegheny County, Pennsylvania. USGS Quadrangles: Pittsburgh West, Pennsylvania (7.5-minute series, 1993), Sixth and Seventh Street bridges; Pittsburgh East, Pennsylvania (7.5-minute series, 1993), Ninth Street Bridge. UTM Coordinates: 17/584520/4477650 (Sixth Street Bridge) 17/584700/4477750 (Seventh Street Bridge) 17/584840/4477785 (Ninth Street Bridge) Dates of Construction: 1926-28 (Sixth Street Bridge) 1924-26 (Seventh Street Bridge) 1924-26 (Ninth Street Bridge) Designers: Allegheny Department of Public Works: T. J. Wilkerson, consulting engineer; Vernon R. Covell, chief engineer; A. D. Nutter, design engineer; and Stanley L. Roush, architect. Builders: American Bridge Company (Ambridge, Pennsylvania), superstructure; Foundation Company (Pittsburgh), substructure. Present Owner: Allegheny County. Present Use: Vehicular bridges. Significance: These structures are the only trio of nearly identical bridges, as well as the first self-anchored suspension spans, built in the United States. They are among the only surviving examples of large eye- bar chain suspension bridges in America, and furthermore, unusual for having been erected using cantilever methods. The bridges’ design was a creative response to the political, commercial, and aesthetic concerns of Pittsburgh in the 1920s. Historian: Haven Hawley, August 1998.
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Google map link
http://maps.google.com/?ll=40.444269,-80.000982&spn=0.011725,0.016072&t=h
Dimensions
editmain span 135 m total length 323.4 m
External Links
edit- entry at Structurae.de
- entry at HAER
- Seventh Street entry at BRIDGES AND
TUNNELS OF ALLEGHENY COUNTY, PENNSYLVANIA (pghbridges.com)
- Three Sisters entry at BridgeMeister.com