First proposed more than 50 years ago, the initial section of a new 13-mile, four-lane highway located in the heart of Pennsylvania is scheduled to open to traffic next year. The long-awaited Central Susquehanna Valley Transportation (CSVT) project is expected to reduce congestion and improve safety along a heavily commercialized corridor by separating trucks and thru traffic from local traffic.
STV has been involved with the project for the past 25 years, initially serving as a major subconsultant performing engineering studies and providing planning and preliminary design services. The firm also performed an alternative analysis that informed the draft and final environmental impact statements. In 2004, STV was selected by the Pennsylvania Department of Transportation (PennDOT) to lead the final design for the Northern Section of the project – a 5.3-mile-long four-lane limited access highway along a new alignment running north from PA 147 south of Montandon in Northumberland County.
After the project was put on hold, it restarted in 2013 following the commonwealth’s $2 billion investment in transportation and transit infrastructure (Act 89). With funding in place, STV resumed its work finalizing plans for the Northern Section. The project broke ground in 2016 and has steadily progressed on schedule with STV providing construction consultation and support services.
In a statement after the start of construction, Pennsylvania Gov. Tom Wolf called CSVT, “an example of our commitment to providing a safe and efficient transportation network to those who live and do business in the commonwealth. I am confident this project will spur economic growth and improve the quality of life of Pennsylvanians in the Susquehanna Valley region and beyond.”
The firm played a key role in supporting the construction of the Northern Section’s most complex element, the River Bridge – a new 4,545-foot-long bridge that rises nearly 200 feet above the West Branch of the Susquehanna River.
The bridge is one of nine highway structures being constructed along the CSVT’s Northern Section, not including a temporary bridge over US 15 that was used by construction vehicles to haul 1.3 million cubic yards of excavation to the north. The project also includes a 700-foot-long box culvert under construction.
“During the design phase, we had to consider several constructability concerns regarding this bridge,” said Project Manager Barbara Hoehne, P.E. “Because this project is on a new alignment and runs through a rural area, the design needed to accommodate ways to transport construction materials to the site. But the project’s greatest challenge regarding its constructability is the fact that it’s a very tall structure, rising about 180 feet over the river.”
Since the bridge is located near a small airport, the team had to consult with the Federal Aviation Administration on the placement of warning lights on the structure itself, as well as on the towering cranes used to lift the massive 10-foot-high steel-plate girders into place.
The bridge’s location along the river valley also posed unique climatological challenges. As part of post-design activities, STV hired a subconsultant to collect wind data and perform a wind tunnel analysis that PennDOT will use to determine the implementation of any potential travel restrictions on the River Bridge, such as those for trucks using the bridge during instances of high winds or inclement weather.
To assist in the bridge’s erection, temporary haul roads and causeways were constructed to deliver nearly 50,000 cubic yards of concrete and 20,000 tons of steel to the site. These materials were used to build 14 bridge piers ranging from 60 to 180 feet high carrying 15 spans over the river, its floodplain, three railroad tracks, PA 147, and a local road.
The Northern Section includes new interchanges with US 15 south of Winfield and PA 147 south of Montandon. The project also includes the relocation of SR 1024 (Ridge Road) in Northumberland County as well as the reconstruction of local roadways, and the construction of a service road that provides residents access to a private drive.
Now that the project is nearing completion – the Northern Section is expected to open to traffic in late Fall 2022 – Hoehne said it’s gratifying to see just how far the CSVT project has come since its early study and design phases.
“While touring the project with the local chapter of the American Society of Highway Engineers, it was exciting to be out there and see it,” Hoehne said. “This region has been waiting for this project for decades. It is a gamechanger for the area and to be able to deliver something that’s so important and has been on the books for so long is something I’ll always be proud of.”
