In 1931, the uniquely designed Boston Bridge was built by Fort Pitt Bridge Works in Versailles, Pa., over the Youghiogheny River.
The 1,182-ft. (360 m) bridge carries SR 48, between Elizabeth and Versailles in Allegheny County. In addition to crossing over the river, the bridge also traverses the CSX Railroad, the Youghiogheny River Trail and two local roadways.
“This extraordinary bridge, which is considered eligible for the National Register of Historic Places, is a striking and impressive cantilever bridge that is very unlike most cantilever bridges encountered,” said Nathan Holth, author, photographer and webmaster of www.historicbridges.org. “The bridge was designed to look highly attractive, and as such the sway bracing on this bridge was constructed as unusual large arch shapes. The top chord of the cantilever was carefully designed especially between the towers to give a very smooth, curved appearance to the bridge.
“The curve was fashioned so that the top chord sweeps far lower than in most cantilever bridges, which is only possible because the bridge has sway bracing only in the vicinity of the towers, yet another unusual feature of this bridge,” Holth continued.
“The suspended span at the center of this bridge has been blended in and hidden more carefully than on most cantilever bridges. The bridge’s clean and streamlined appearance is due in part to the fact that the diagonal and vertical members are all rolled beams, and the top chord is a built-up box beam with lattice on the bottom, which is the only place in which lattice occurs on the bridge. No v-lacing is present. At least some and perhaps all the steel on the bridge was fabricated by Carnegie Steel Company of Pittsburgh.”
The Boston Bridge may have been modeled after the Three Sisters Bridges (6th, 7th and 9th Streets) in Pittsburgh, which were erected a few years earlier by the American Bridge Company of New York.
Its last renovations were in 1989. This time around, the Pennsylvania Department of Transportation (PennDOT) improvements include replacing the concrete filled steel grid deck, sidewalk and stringers; reinforcing steel floor beams; new PA barriers, rehabilitation of existing pedestrian railings; replacing existing expansion dams and replacement of retrofitting bearings.
The project also includes crack repair/re-pointing of stone piers, repair of spall and delaminated concrete on abutments and pedestal foundations, and repainting the entire structure.
“This bridge is very important to the community,” noted Heath Butler, project manager of PennDOT. “The next closest bridge is the 15th Street Bridge, between Liberty Borough and McKeesport.”
The car detour that will be set up during the project takes travelers through Elizabeth, Liberty and McKeesport for approximately 12 mi. Trucks will use SR 51 across the Elizabeth Bridge to SR 837, then through Clairton and Dravosburg for 30 mi.
PennDOT has made arrangements to keep the Youghiogheny Trail open during construction, and has partnered with CSX to continue rail service through the use of flagmen. There also is an adjacent baseball field that will remain accessible to the public.
The $17.3 million contract was awarded to Trumbull Corporation of Pittsburgh. The project is entirely funded by former Gov. Ed Rendell’s “Rebuilding Pennsylvania” initiative. The governor’s 2008-09 budget proposal contained the initiative that provides $200 million annually in bond financing over a ten-year period to address Pennsylvania’s state-owned structurally deficient bridges.
Physical work began on the bridge in fall 2010, followed by a scheduled winter hiatus from December 2010 to the end of February 2011. The work restarted in March with preparing and painting of the superstructure.
Trumbull will be performing the demolition, placing new concrete decks, sidewalks and abutments. It will use approximately 600 cu. yds. (458.8 cu m) of concrete for the bridge deck. The sidewalks and roadway require 150 cu. yds. (114.7 cu m) of concrete each. About 276 cu. yds. (211 cu m) of concrete will be needed for the structure barrier, and another 12 cu. yds. (9.2 cu m) for the substructure.
Subcontractor Advanced Painting Systems, also based in Pittsburgh, was subcontracted for $3.8 million to paint the bridge. The steel will be erected by Century Steel Erectors, headquartered in Dravosburg; L.B. Foster Company of Pittsburgh is supplying the grid deck and grid sidewalks, and Beth’s Barricades of Gibsonia is supplying and erecting the traffic control signs. Power Contracting Company of Carnegie will perform the electrical work through a $100,000 contract.
A contract for $2.3 million was apportioned to Michael Baker Jr. Corporation for construction inspection services. Baker also will provide construction management services throughout the project, as stated in a separate contract.
Crews are set up to do half-width construction on the bridge deck, with single direction detours from May to August of this year. There also will be periodic nighttime and weekend closures through December 2011.
“The rehabilitation designs are in keeping with the bridge’s historical appearance,” said Butler. “The decorative hand-railing on both sides of the bridge will be removed, restored and reinstalled.”
For more information, visit www.historicbridges.org.
CEG
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