Friday, September 23, 2022

1897+1937,1979,2006 Homestead Grays (High Level) Bridge over Monongahela River

(Bridge Hunter; Historic Bridges; pghbridgesSatellite)

It is also called the Homestead High Level Bridge. It is 3,109' long with two 534' main spans. Average daily traffic in 2006: 35,235. [BridgeHunter]
"109.3 ft, vertical clearance, at center line of channel span. Emsworth Dam normal pool level 710 ft" [pghbridges]
This bridge replaced the Homestead & Highland Bridge aka Brown's Bridge.

Street View

3D Satellite

Street View

"This bridge is an extremely long bridge that is noted for the rare Wichert truss design. This modification of the traditional continuous/cantilever design is noted for an unusual design above the piers of the bridge, where the truss has a special shape that was designed to mitigate some of the problems that were involved with the design of continuous truss bridges in the first half of the 20th Century. The trusses on a Wichert take the shape of a rhombus over each pier." [HistoricBridges]
 
Steel Valley History posted
1938-High Level Bridge
Bob Kline: US Steel , Homestead Works , on the right-hand side .

Frank Kish posted
Text on the back: "HOMESTEAD, PA.
View of the Homestead United States Steel Works -- one of the world's largest and oldest steel production mills in the world.
Color by Goll Studio"
Scott Layman: Wow such a great picture….the bridge still stands.

Digitally Zoomed

pghbridges
"The new bridge, constructed at a cost of $2,800,000.00, was dedicated in 1937. In 1941, 'United States Steel Homestead Works, under the direction of United States Government's Defense Plant Corporation, expanded thereby causing the demolition of 1,225 buildings in lower Homestead. Over 3,500 people were to be relocated. The new plant expanded with 11 steel furnaces, a 45 inch slab mill, 160 inch plate mill, a forging, heating and machine shop. Homestead now was capable of producing armor plate for useby the Navy on it's battleships and cruisers.'
[If you look at Frank's postcard you can see that most of the homes in this postcard were wiped out as part of the steel mill expansion. There is a comparable view in HistoricPittsburgh that still shows the homes in the area. But their information concerning the rights to the photo was too confusing for me to copy it.]
"Before the use of computers, the interaction of forces on spans which crossed multiple supports was difficult to calculate. One solution to the problem was developed by E. M. Wichert of Pittsburgh, PA, in 1930. By introducing a open, hinged quadrilateral over the intermediate piers, each span could be calculated independently. Another Wichert Truss is the Charles Anderson Bridge carrying the Boulevard of the Allies over Junction Hollow in Oakland.
"July 12, 2002, the bridge was renamed the Homestead Grays Bridge in honor of the Negro League baseball team. The team began as a group of steelworkers in 1912. As they were banned from playing in the Major Leagues, the Negro Leagues (National and American) were formed in the 1920s and continued into the 1950s. The Grays and the Pittsburgh Crawfords were the city's Negro National League teams. The Grays dominated the league from the start with 10 pennants and 3 World Series. The league disbanded soon after Jackie Robinson became the first player to break the color barrier when he joined the Brooklyn Dodgers in 1947."

Any cut-stone pier is worthy of note.
Aug 2010 Photo by Jason Smith via BridgeHunter
East Pier

One of the piers is on land and a street view driver went into the parking lots, so I could get a good view of the rombus shape of the truss members above a pier.
Street View
 
Engineering News-Record via HistoricBridges
 
aisc
"The Wichert truss is a continuous steel truss with hinged quadrilaterals (rhomboids) over the interior piers where a hinge is in each corner. The use of the hinged quadrilaterals allows for each span to be considered independently for member force calculations and design....In the 1930s, well before the use of computers in bridge design, the analysis and determination of member forces of continuous span trusses were statically indeterminate and difficult to calculate. The Wichert truss, on the other hand, is statically determinate, and influence lines could be readily used to determine member forces and complete the design.
"In his 1932 book, "The Wichert Truss," David B. Steinman writes that the Wichert truss retains the rigidity of the rigid continuous truss but possesses several advantages, such as economy in truss material and foundations; economy in cost and construction time; adaptability to beauty; and ease of analysis. Member stresses are negligibly affected by pier settlement and a Wichert Truss may be used where cantilevered truss construction would ordinarily be required."

1 of 3 photos from msconsultants
This article describes the work that was done in 2006-07 and 2019, including the widenting of the deck from 40' to 46'.

aisc
The southern approach consists of six Wichert continuous trusses.

The southern approach also has several steel girder spans.
Street View

1897 Brown's Bridge via HistoricBridges

Here is another view of the Brown's Bridge.  All of the homes between the railroads and the river were removed to make way for the Homestead Mill's expansion for WWII. This illustration of how much the mill was expanded is why I added the "military" label to these notes.
Dennis DeBruler



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