Since 1999, the PTC has been working on a total ground up reconstruction of “America’s First Superhighway”—an important long-term investment of more than $1 billion over the next decade. The nine-mile area between Milepost 85-94 included a sharp curve with a high crash rate. The Turnpike also was interested in widening the corridor to improve safety and capacity.
The Approach
McCormick Taylor provided preliminary and final engineering design for the nine mile project. Critical design features included widening the median by eight feet throughout the project, extending a third eastbound lane for six miles, adding a one-mile westbound climbing lane and relocating ¾ mile of the turnpike mainline to correct a sharp curve. The horizontal and vertical alignments were adjusted to remove substandard curves and clearances. Numerous walls were designed to allow the highway to be widened in the western section between a steep rock cut and Jacob's Creek.
An early-action design-build PS&E was prepared as part of this project to remove two overhead structures, construct a ½ mile frontage road, and replace another overhead structure. Another early-action PS&E was prepared to replace two PennDOT overhead bridges.
The Result
To keep the Turnpike moving and effective, the team maintained two travel lanes per direction during all long-term stages of construction, which consisted of three major construction phases. This project also included the preparation of detour plans to re-route traffic when the westbound ramps of Interchange 9 (Donegal) were closed to allow for bridge reconstruction. Reconstruction of the area between Milepost 85 and 94 was completed over a year earlier than initially anticipated.
