In the early 20th century, three affluent Philadelphia families purchased early farmland, transforming it into impressive country estates in Delaware and Chester Counties. This era concluded in the late 1940s, leaving behind a rural landscape with preserved agricultural and forested land, along with many historically significant structures.
In 2017, the area was formally recognized as the Twin Bridges Rural Historic District on the National Register of Historic Places. Spanning nearly 2,000 acres on both sides of the Brandywine River in the southern parts of Pennsbury and Chadds Ford Townships, the district’s name originates from two covered tandem bridges that once crossed the Brandywine River, known as the Pyles Twin Bridges.
The SR 3101, South Creek Road Bridge over the Brandywine Creek was the first replacement of the twin covered bridges. Built in 1925, this six-span reinforced concrete closed spandrel arch bridge stands on the boundary between Pennsbury Township, Chester County, and Chadds Ford Township, Delaware County. The bridge’s southernmost span traverses over the East Penn Railroad’s single track, while the remaining spans cross the Brandywine Creek and its floodplains. Notably, the bridge lacks sidewalks or shoulders and there are weight and length restrictions that can impact traffic in the area.
GPI conducted preliminary engineering work, exploring various options that met the requirements for a bridge rehabilitation or replacement bridge. This road segment is a part of the Delaware County Bicycle Plan and serves as Bicycle PA Route L. The scope of work included Hydrologic and Hydraulic (H&H) analysis in a detailed FEMA floodway, preparing the permit package, and producing a Condition Letter of Map Revision (CLOMR). The environmental studies covered archeological investigations, wetlands, bog turtle, and red-bellied turtle habitat assessments. The environmental clearance activity included Section 106 Consulting Party coordination. Additionally, GPI prepared an Aid to Navigation (ATON) plan due to the structure crossing a recreational waterway. The project also involved surveying, geotechnical investigations, roadway design, maintenance and protection of traffic, and coordination with the railroad.
Project Highlights
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Owner/ClientPennsylvania Department of Transportation
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LocationChester and Delaware Counties, PA
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ServicesBridge Engineering
Hydrology & Hydraulic Design
Roadway Engineering
Structural Engineering