The Three Sisters are three very similar self-anchored suspension bridges spanning the Allegheny River in downtown Pittsburgh, Pennsylvania at 6th, 7th, and 9th streets, generally running north/south. The bridges have been given formal names to honor important Pittsburgh residents:
The Smithfield Street Bridge is a lenticular truss bridge crossing the Monongahela River in Pittsburgh, Pennsylvania, USA.
The Coraopolis Bridge is a girder bridge over the back channel of the Ohio River connecting Grand Avenue on Neville Island to Ferree Street in Coraopolis, Pennsylvania. It opened in 1995 to replace a structure of historic significance. The original Pratt/Bowstring/Pennsylvania through truss spans, designed by Theodore Cooper, were formerly the (third) Sixth Street Bridge, spanning the Allegheny River, in downtown Pittsburgh, and were built in 1892 by the Union Bridge Company. They were floated downstream by the Foundation Company in 1927 rather than being demolished when the bridge was removed to enable construction of the present (fourth) Three Sisters (Pittsburgh) Sixth Street Self-anchored suspension bridge. However, by the late 1980s, the old bridge could no longer support traffic volumes and was replaced by a newer structure.
The Hot Metal Bridge is a truss bridge in Pittsburgh, Pennsylvania, that crosses the Monongahela River. The bridge consists of two parallel spans on a single set of piers: the former Monongahela Connecting Railroad Bridge, built in 1887, on the upstream side and the former Hot Metal Bridge, built in 1900, on the downstream side. The Monongahela Connecting Railroad Bridge carried conventional railroad traffic, while the Hot Metal Bridge connected parts of the J&L Steel mill, carrying crucibles of molten iron from the blast furnaces in ladle transfer cars to the open hearth furnaces on the opposite bank to be converted to steel. During World War II 15% of America's steel making capacity crossed over the Hot Metal Bridge, up to 180 tons per hour. The upstream span was converted to road use after a $14.6 million restoration, and opened by Mayor Murphy with a ceremony honoring former steel workers on June 23, 2000. The bridge connects 2nd Avenue at the Pittsburgh Technology Center in South Oakland with Hot Metal Street in the South Side. The downstream span reopened for pedestrian and bicycle use in late 2007 after two years of work. The Great Allegheny Passage hiker/biker trail passes over this bridge as it approaches Pittsburgh's Golden Triangle area.
The Fort Wayne Railroad Bridge, listed as the Pennsylvania Railroad Bridge on the National Register of Historic Places, is a double-deck steel truss railroad bridge spanning the Allegheny River in Pittsburgh, Pennsylvania.
The West End Bridge is a steel bowstring arch bridge over the Ohio River in Pittsburgh, Pennsylvania, approximately one mile below the confluence of the Allegheny and Monongahela Rivers. The bridge was built from 1930 to 1932 primarily by the American Bridge Company (superstructure) and the Foundation Company (substructure) and was the world's first to use tied-arch technology on a large scale. It connects the West End to the Chateau neighborhood on the North Side of Pittsburgh. The bridge was placed on the National Register of Historic Places in 1979, and the List of Pittsburgh History and Landmarks Foundation Historic Landmarks in 2001. As of 2016, the bridge and its surrounding approaches are undergoing some major reconstruction.
Wendel Bollman was an American self-taught civil engineer, best known for his iron railway bridges. Only one of his patented "Bollman truss" bridges survives, the Bollman Truss Railroad Bridge in Savage, Maryland. The Wells Creek Bollman Bridge near Meyersdale, Pennsylvania is also standing, although that bridge uses the Warren truss system.
The McKees Rocks Bridge is a steel trussed through arch bridge which carries the Blue Belt, Pittsburgh's innermost beltline, across the Ohio River at Brighton Heights and McKees Rocks, Pennsylvania, west of the city.
The Brady Street Bridge, also known as the South 22nd Street Bridge, was a steel bowstring arch bridge in Pittsburgh, Pennsylvania, which crossed over the Monongahela River at South 22nd Street. It was replaced by the Birmingham Bridge in 1976, and was demolished on May 29, 1978. The bridge's main span was a tied arch with a suspended road deck, with two through-truss side spans, carrying two traffic lanes between Brady Street on the Pittsburgh side and South 22nd Street on the south side. Approach viaducts were built at either end. The bridge was built by the Schultz Bridge and Iron Company.
The Herr's Island Railroad Bridge, also known as the West Penn Railroad Bridge, is a truss bridge across the Allegheny River between the Pittsburgh neighborhoods of Troy Hill and Herrs Island.
The Bessemer & Lake Erie Railroad Bridge it is a truss bridge that carries the Canadian National Railway's Bessemer and Lake Erie Railroad division across the Allegheny River between the Pittsburgh suburbs of Plum and Harmar Township, Pennsylvania. In 1897, a single-track trestle and viaduct was built on this site; in 1918, the original piers were doubled in width, the current double-tracked structure built alongside, and then slid into place. The original north trestle approach was buried in slag dumped from an adjacent temporary filling trestle.
The Emlenton Bridge is a steel-deck truss bridge that spans the Allegheny River just south of the town of Emlenton, Pennsylvania, United States at approximately mile marker 44.4 on I-80. With a height of 270 feet (82 m) above the river, the Emlenton Bridge was the highest bridge in the Interstate Highway System when completed in 1968. This record was held until 1971 with the opening of the Fred G. Redmon Bridge near Selah, Washington.
The Brownsville Bridge, also known as the Intercounty Bridge and the West Brownsville Bridge, is a truss bridge that carries vehicular traffic across the Monongahela River between Brownsville, Pennsylvania and West Brownsville, Pennsylvania. Since the opening of the Lane Bane Bridge and highway project to carry much of the intercounty through traffic away from the main streets of downtown Brownsville in the early 1960s, another commonly heard name is Old Brownsville Bridge for the four high level viaduct.
Pennsylvania Railroad, Connecting Railway Bridge is a stone arch bridge in Philadelphia, Pennsylvania, that carries Amtrak Northeast Corridor rail lines and SEPTA and NJT commuter rail lines over the Schuylkill River. It is located in Fairmount Park, just upstream from the Girard Avenue Bridge.
The Oil City Pennsylvania Railroad Bridge is a truss bridge that carries the Western New York and Pennsylvania Railroad (WNY&P) across the Allegheny River between Cranberry Township and Oil City, Pennsylvania. The bridge was originally built to serve the Pennsylvania Railroad as part of its Buffalo Line. WNY&P is the fourth owner of the structure. After the breakup of the Pennsy, Conrail took ownership of the line. The breakup of these company saw Norfolk Southern assigned the rights; the WNY&P took ownership in 2006 as they extended their trackage from Meadville, Pennsylvania to Oil City. Because the bridge once served as a major junction point for several Pennsylvania Railroad lines, it features a unique approach structure. One section went from Oil City through Tidioute, Pennsylvania and then on to Warren, Pennsylvania. Conrail abandoned this line in 1976, but it may re-open so that the WNYP has a direct route to Warren.
The Inclined Plane Bridge is a 237-foot (72 m), Pennsylvania through truss bridge that spans Stonycreek River in Johnstown, Cambria County, in the U.S. state of Pennsylvania. It connects the city to the lower station of the Johnstown Inclined Plane. The bridge was listed on the National Register of Historic Places in 1988 and was documented by the Historic American Engineering Record (HAER) in 1997.
The Manchester Bridge, also known as the North Side Point Bridge, was a steel Pratt truss bridge that spanned the Allegheny River in Pittsburgh, Pennsylvania.
The Point Bridge was a steel cantilever truss bridge that spanned the Monongahela River in Pittsburgh, Pennsylvania.
The Beaver River Railroad Bridge crosses the Beaver River in New Brighton, Pennsylvania, carrying the tracks of the CSX Railroad. It was built in 1926, to a design by J.F. Leonard, the Pennsylvania Railroad's engineer in charge of bridges and buildings, for the Pittsburgh, Fort Wayne and Chicago Railway. The riveted Warren deck truss main span and riveted deck girder western side spans have a total length of 1,221 feet (372 m). The deck truss spans vary from 122 feet (37 m) to 219 feet (67 m), some of which are unusually shallow and skewed. It replaced an 1887 span, which was converted to road use, continuing in that role until it was replaced in 1985.
