A southern-facing aerial view of the Mifflin Road Bridges project.
The Mifflin Road Bridges project in Allegheny County, Pa., takes place amidst a labyrinth of roads and interchanges just south of a dip in the Monongahela River. This area, approximately 6 mi. (9.6 km) southeast of downtown Pittsburgh, was in need of two new bridges to accommodate increased traffic demands.
The $8.1 million contract includes repairs to Bridge 8, which is a six-span pre-stressed I-beam bridge, and Bridge 7 — a three-span pre-stressed spread box beam bridge. Approximately 3 mi. (4.8 km) away on SR 2046 (Streets Run Road), a small bridge crossing over Streets Run also is being replaced in conjunction with this project.
Prime contractor Swank Associated Companies of New Kensington, Pa., broke ground in July 2010. Swank is responsible for demolition and concrete work, pavement associated with approach work and drainage. The whole project will be complete this fall.
Both bridges 7 and 8 are receiving complete bridge preservation work, including replacement of neoprene beam pads, new bridge barriers, expansion dams, highway lighting and drainage. There also is approximately 70 to 90 ft. (21 to 27 m) of approach work for the bridges.
Bridge 8 is a 500-ft. (152 m), six-span dual bridge with two northbound and two southbound lanes separated by a mountable curb. It carries SR 885 over Streets Run Road (a.k.a. Baldwin Road), Streets Run and the Allegheny Valley Railroad. In 2010, the northbound deck was completed and traffic has been routed to this deck while the two lanes of the southbound bridge are renovated.
This bridge also has a dedicated exit lane for Streets Run Road.
PennDOT estimates that crews are about six weeks ahead of schedule on this bridge, which should be fully open in late September.
Bridge 7 is located approximately .25 mi. (.4 km) north of Bridge 8, and it exclusively carries southbound SR 885 over Glass Run Road. The 130-ft. (40 m) bridge was closed on May 23, 2011, and a detour was put in place, making northbound 885 a bi-directional road for the duration of the project.
PennDOT reopened the bridge on Aug. 13.
Work on the SR 2046 / Streets Run Road Bridge began in July 2010. Swank is performing a complete bridge and culvert removal, and widening the two lanes from 24 to 50 ft. (7.3 to 15 m) to accommodate truck traffic. The bridge crosses over Streets Run, a 10-ft. (3 m) wide tributary of the Monongahela River. The Lane Construction Corporation, Pittsburgh office, was subcontracted for the bituminous paving work on Streets Run Road.
Other subcontractors on the project include Zavalla Inc. of Pittsburgh for electrical work; Protection Services Inc. (PSI), headquartered in Harrisburg, for traffic control; and Robinson Pipe Cleaning of Pittsburgh for pipe cleaning. Additionally, Green Acres Contracting of Scottdale is providing guiderails, and Strongstown B&K, based in Strongstown, was contracted for structural work, including a mounted barrier for Bridge 8 to protect the bridge that is open to traffic. CEG
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