The CSVT project has been in the works since a Route 15 corridor study was completed in 1959. The environmental engineering firm Skelly and Loy, now a Terracon company, got involved in 1995, says vice president Sandy Basehore. “We put a proposal together as a prime, with an engineering sub,” she recalls. “Typically, we are the sub. We knew what would drive the project was an environmental analysis for where it would be placed.”

It wasn’t until the passage of Act 89 in 2013 that funding became available to complete the project. Thirty alternatives were explored within a footprint of 43,000 acres, says Basehore, with wetlands, waterways, forests, cultural and local resources all in play.

The new crossing over the Susquehanna River is PennDOT’s 8th-largest.
Photo courtesy of Trumbull Corp.

Challenges included an undocumented closed landfill, trout populations, a river floodplain,  and dammed fly ash basins. “The preliminary alignment went over some fly ash basins” that were initially thought to be stable enough, says David Hamlet, project manager with Gannett Fleming, which served as construction inspector for the northern section and as final designer on the southern section. The basins’ stability was affected by underground springs. “We found it was like toothpaste,” he recalls. “Ultimately, [the highway] needed to go around them.”

 STV, which completed final design for the northern section, worked with geotechnical consultants to minimize the potential excavation of acid-bearing rock near the river, recalls Barbara Hoehne, STV technical director. Matthew Beck, assistant plans engineer with the Pennsylvania Dept. of Transportation, says the 2 million cu yd of potential impacts was reduced to 400,000 cu yd.

Terracon also built a predictive model to identify potential impacts to historically significant entities, adds Beck. After stops and starts through the past half-century, “once we picked it back up in the mid-’90s, we held 150 public meetings over an 8-year period” he says.

Acquiring parcels of land, many of them farms, was also challenging. PennDOT had to obtain approval three times from an agricultural lands condemnation approval board. “You have to prove without a doubt that you are on the most reasonable path,” says Basehore.

The Susquehanna River bridge, PennDOT’s eight-longest, required building a 45,000-ft-long rock causeway in the river, one half at a time, with footings of 70 ft x 70 ft and as deep as 80 ft, and circular concrete-segment cofferdams, says Stahl. The 14 piers vary in height from 75 ft to 180 ft and are supported by spread footings on rock or caissons with pile caps and stub abutments supported on steel piles, according to SAI Consulting Engineers, the structural engineer.

Crews utilized temporary lateral bracing to support girders until the 90-ft-wide deck was poured, says Stahl. Precast, prestressed, post-tensioned beams required a "very large crane, with counterweights that scoped out as you went down," he adds. "We couldn’t move very fast and we needed a solid base." Subcontractor Century Steel Erectors used a crane with capacity up to 800 tons, and two others at 600 tons, he adds.

The Susquehanna River bridge rises almost 200 ft and is 4,545 ft long.
Photo courtesy of Trumbull Corp.

Trumbull also held a $61-million contract on the northern section to move 2.5 million cu yd of earth, while New Enterprise Stone & Lime held two contracts for a total of $89 million for paving and other structures.

Southern Section

Trumbull is now in the midst of a $115-million contract to move some 5 million cu yd of earth for the southern section, while Walsh has a $106-million contract for nine bridges and four noisewalls, says Beck. A paving contract is slated for award in 2026.

While not as challenge-ridden as the northern section, ongoing construction requires constant monitoring, notes Basehore. That includes stormwater management, and potential impacts to bats and an eagle’s nest. “We have to demonstrate that rock blasting is not more disturbing to them than planes taking off” from a nearby airport, says Paul DeAngelo, biologist and director of natural resource analysis with Skelly and Loy.

The northern section is carrying 16,000 vehicles per day, including 3,800 trucks that used to use local roads. “This project completes a missing link,” says Hoehne. "For us, whether we're the sub or the prime, engaging with PennDOT and other agencies—this has been on the books and minds for decades."