May
28,
2004
Norfolk Southern Railroad Truss Bridge Aerial View |
(Valley Forge, Pa.) The Norfolk Southern
Railroad Truss Bridge over Interstate 76 (I-76) was presented with a Pennsylvania
Partnership for Highway Quality (PPHQ) award in the structures category (greater
than 150 feet) in the 2004 PPHQ Awards Program. This annual awards
program recognizes quality achievements in the design and construction
of highways throughout Pennsylvania.
Cross section |
Gannett Fleming, an international planning, design and construction
management firm, designed the bridge for the Pennsylvania Department
of Transportation, District 6-0. This project required a railroad
bridge crossing over I-76, new collector-distributor lanes, and a
new ramp connecting U.S. 422 to I-76. These factors resulted in a
485-foot-long bridge with two equal, 240-foot-spans.
The design team faced several challenges, including improving traffic
safety, minimizing traffic restrictions during construction, and
reducing the duration of bridge construction. These challenges were
met in spite of not having adequate bedrock foundation support for
the replacement bridge.
Launch nearing pier |
Minimizing public impact was of particular importance because the truss
bridge is located in an area that experiences the highest concentration
of traffic in all of Pennsylvania. However, despite the size of the
spans and magnitude of construction, traffic restrictions were minimal
and only a 15-minute traffic stoppage on I-76 was necessary for the
span launch.
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