I-81 Susquehanna River Bridges Replacement P3

Replacement of Two Aging Bridges Will Improve Pennsylvania’s Transportation Infrastructure

Project Highlights

• Replacement of two 680 ft long bridges over the Susquehanna River
• New structures will feature precast girders 175 ft long and 227,000 lbs each
• 520-ft-long trestle capable of supporting multiple 300T cranes will be installed across the entire river for each phase
• First two major phases of work are constructing half widths of the southbound bridge
• The northbound bridge will be demolished and constructed in the final phase
• Additional work will update interchange designs and storm drainage

The I-81 Susquehanna Project is one of six critical interstate highway locations in Pennsylvania being addressed through the PennDOT Major Bridge Public-Private Partnership (P3) project, a megaproject for the financing, design, construction, and future maintenance of a total of 23 structures and 21.27 miles of roadway approaching the end of their useful life.

S&B USA companies have key roles in this megaproject. S&B USA Construction is a member of Bridging Pennsylvania Constructors (BPC), the construction joint venture responsible for constructing and maintaining all bridges and related infrastructure in the program. S&B USA Concessions, a leader in delivering successful P3 projects, is a member of Bridging Pennsylvania Developers - I (BPDI), which is contracted to deliver the projects.

In the I-81 Susquehanna Project, Fay, S&B USA Construction (Fay) is subcontracted to demolish and replace the dual northbound and southbound I-81 bridge structures over the Susquehanna River.
 

Problem

• Aging infrastructure: A majority of the roadway and infrastructure are approaching 60 years old, and the Susquehanna River Bridges are nearing the end of their serviceable lifespan.
• Outdated interchange designs: The on and off ramps at interchanges throughout the corridor do not meet current or future traffic design standards.
• Drainage concerns: The storm system built into much of the corridor now exceeds its service life.

The two bridges spanning the Susquehanna River were originally built in 1961 and rehabilitated three times through 2006. Each of the bridges is 680 ft long and 35 ft above the water. The structures carry about 27,000 vehicles per day, approximately 41% of which is truck traffic, and traffic volume is expected to more than double to approximately 55,000 vehicles daily by 2045.

The contractor is expected to maintain two lanes of traffic in both directions, except for limited single-lane closures during off-peak hours.
 

Solution

Fay will replace the northbound and southbound Susquehanna River bridges in three phases to ensure two lanes of traffic in each direction during peak hours and one lane during non-peak hours. To accomplish this, Fay designed and constructed a 520-ft-long access trestle across the river that will be removed and reconstructed in a different alignment for each stage of construction. The trestle will be capable of supporting multiple 300-ton cranes.

The precast concrete girders used in spans 2 and 3 of the new structures are 175 ft long and 227,000 lbs each. The precast manufacturer believes these are the longest precast girders used to date on a bridge project in Pennsylvania.
 

Construction

To ensure two lanes of traffic in each direction are maintained throughout the entirety of the project, the northbound and southbound I-81 Susquehanna River Bridges will be replaced in three phases:

Phase 1: I-81 southbound and I-81 northbound will be partially demolished. Then, Fay will begin replacing the first half of the southbound bridge.
Phase 2: The new southbound bridge will be completed.
Phase 3: Fay will finish demolishing the northbound bridge and reconstruct it in its entirety.

Nearly all of the construction will be performed from a 520-ft-long trestle that will be installed and removed three separate times to accommodate this phasing. Fay will install cofferdams in the river to drive piling and erect three concrete piers in each direction.
 

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To learn how our team of heavy construction and demolition experts can help solve your bridge and infrastructure challenges with safe and innovative solutions, contact us.