Crews Forge Twin Spans Over the Susquehanna

Thu December 27, 2007 - Northeast Edition
Mary Reed



A $60 million bridge project currently under way in Pennsylvania’s Lycoming County is expected to enhance revitalization efforts taking place in downtown Williamsport as well as create a direct connection between SR 15 and I-180.

The Susquehanna River Bridge carrying SR 15 and linking Williamsport and South Williamsport is in the process of being replaced with twin bridges, in tandem with construction of a single point urban interchange (SPUI) connecting SR 15 and I-180. As a result, Via Bella, which parallels I-180, will see a reduction in traffic and is to be converted from four lanes to two.

Funding for the job is split between federal (84 percent), state (15 percent) and local (1 percent) sources, and the project has an estimated time of completion of July 1, 2008. Trumbull Corporation, based in West Mifflin, Pa., is prime contractor.

About the Project

Pennsylvania Department of Transportation (PennDOT) is performing project oversight, including documentation and inspection. PennDOT personnel working on the job have varied between 10 and 15 individuals, with Trumbull’s workforce including project management staff, at approximately 80, not including subcontractors.

“The southbound half of the SPUI and the southbound river crossing were built first, while traffic was maintained on the old bridge,” said Aaron Crist, PennDOT project manager.

“When that work was completed, northbound and southbound traffic was placed on the new bridge and the old bridge was demolished. The new northbound bridge is being built on the location of the old bridge.”

“We have completed all of the substructure work for the twin eight-span pre-stressed concrete I-beam bridges over the West Branch of the Susquehanna River at Williamsport,” he continued.

“The southbound bridge is completely done and open to traffic and the northbound has all its beams set and the deck is about 75 percent complete, with parapets about 50 percent complete.

“The river bridges tie into a SPUI structure on the north side of the river. The SPUI substructure is complete and all of the structural steel is set for the superstructure,” he explained.

“The latter consists of eight three-span welded steel mainline I-girders with steel girders framing into the fascia girders to connect the ramps to the main structure.

“Construction of the roadway approaches in Williamsport and South Williamsport is under way,” Crist stated.

“The second bridge and interchange are scheduled to be open no later than October 26, 2007. After the bridge and SPUI are open and fully functional, Via Bella, the street that connected U.S. 15 to the old bridge, will be reconstructed.”

This reconstruction will include replacing three signalized intersections with roundabouts, the work to be carried out in spring 2008.

Recently, the placing of bridge deck, construction of MSE walls, and bituminous paving were carried out.

Equipment used for the project includes a Caterpillar IT28F rubber-tired loader, 345BL and 330CL excavators, M318 rubber-tired excavator, 14G grader, and a D8K bulldozer. Link-Belt cranes — two LS238 track cranes and an RTC8065 rubber-tired crane — also are working on the job, along with ICE I-19 pile and 4450 vibratory hammers, JLG 860 AJ, JLG 660SJ and JLG 860SJ lifts, Bidwell deck finishing machines, and an Ingersoll Rand SD100 roller. The equipment fleet also includes a John Deere 650H bulldozer with GPS, and a Bobcat 331 mini-excavator.

Problems to Overcome

One or two problems had to be overcome but caused little delay to the project.

Due to the complex geometry of the bridge deck where the SPUI ramps tie into the main bridge it was impossible to place the deck with a single deck machine. The ramps split into two lanes, one turning north and the other south, and are on tight radii going in opposite directions as well as being superelevated in opposite directions.

“To solve this problem the contractor chose to use two deck machines, one for each lane,” Crist explained. “The inside rails for the two machines actually crossed at one point, requiring removal of a section of rail. Further complicating things was the fact that the inner rails did not run along any of the girders, making it a challenge to support the rail. Where the rail happened to cross the girder it could be supported directly on the girder, but between girders the rail had to be supported.”

“The stay-in-place deck forms (SIPs) were not strong enough to support the rail,” he continued.

“The contractor devised a system using overhang jacks attached to the girders under the SIPs to support the rail. These were then extended up through the SIPs and this system provided a stable rail to run the deck machines.”

Another difficulty to be overcome was the schedule required placing concrete during winter weather.

“To maintain cure temperatures the contractor wrapped the metal forms with ground heater hoses before enclosing the forms with insulating blankets,” Crist said.

“Ground King E300 ground heaters preheated the forms and then kept the concrete above the required 50-degrees Fahrenheit required by the specs.”

Crist noted that maintaining traffic throughout the many phases of construction has been a challenge, but the extensive planning and publicity have paid off, with very few concerns raised.

“This job includes the first above-ground SPUI built in Pennsylvania and is also the largest single contract dollar-wise in PennDOT District 3-0 history,” he concluded. CEG