The Portageville Bridge, also known as the High Bridge, is considered to be the vital link along the Southern Tier Route, crossing the Genesee River in Letchworth State Park in Portageville, NY. Unfortunately, it is the weakest link on the line. Built in 1875, the historic 820-foot steel viaduct can no longer meet the demands of a Class 1 Heavy Freight Railroad. Norfolk Southern needed to find a solution for this tired workhorse. They turned to trusted bridge engineering firm Modjeski and Masters to help solve their infrastructure challenges.
Our technical experts began by inspecting and rating the existing bridge, which confirmed the near-exhausted useful life and limited load-carrying capacity of the structure. Next, Modjeski and Masters helped guide Norfolk Southern through the New York State Environmental Quality Review (SEQR) process, the necessary first step to restore and optimize the Southern Tier Route’s capacity, without impacting the scenic park viewshed. Construction resulting from an intensive rehabilitation would likely interrupt rail operations on the Southern Tier Route. The preferred alternative to rehabilitation included a complete replacement of the bridge on an adjacent parallel alignment. Modjeski and Masters’ engineers next developed conceptual bridge replacement designs which ranged from a modern-day version of the existing truss bridge to an iconic steel arch spanning the entire width of the gorge. The concepts were showcased through a Visual Impacts Analysis (VIA), from which the latter concept – an iconic long span steel arch – was advanced to preliminary design. During the preliminary design phase, we provided rigorous engineering services to establish structure and track geometry (including the arch’s impressive 483-ft. main span), member sizing and coordination with Letchworth State Park. A geotechnical investigation was needed for the arch buttress and restructured gorge wall at the foundation. Limitations of construction impacts were also identified.
Modjeski and Masters designed approximately 4,200 linear ft. of track realignment for the project. This will provide a modest increase to the allowable operating speed while minimizing impacts to Park resources. The preferred span arrangement of new arch structure required the relocation of Park Road, the High Bridge parking area, and the Mary Jemison and Gorge Trails. Located under the west approach spans at the edge of the River gorge, Park Road was successfully realigned to simultaneously accommodate the arch skewback and pier foundations. This improved roadway alignment results in increased sight distance and better scenic viewing accessibility to Park patrons.
Modjeski and Masters actively worked with Norfolk Southern to determine a safe, economical and aesthetically viable bridge replacement type. Our bridge experts are now performing services for final design of the arch span, including refinement and connection detailing. It can be said that the Portageville Bridge is symbolic of Modjeski and Masters’ longstanding and continued relationship with Norfolk Southern. As in the past, our knowledgeable experts are entrusted with helping the railroad maintain the Portageville Bridge, and keep operations moving on the Southern Tier Route.
“We recognized that the bridge was at the end of its life, but look forward to the next generation bridge to be just as iconic.”Public Involvement Participant
Todd B. McMeans, PE (Principal In Charge)
Leon K. Huang, PE (Principal In Charge - ret.)
Kevin W. Johns, PE (Project Manager)
Daniel B. Irwin, PE (Lead Bridge Engineer)
Michael D. House, PE (Lead Highway/Track Engineer)
Christopher W. Smith, PE (Design Engineer)
Shawn J. Throne, EIT (Design Engineer)
Betsy M. Reiner, PE (Design Engineer)
Hiep N. Bui, EIT (Design Engineer)
Joseph R. Spadea, PE (Lead Design Visualization)
Mike S. Januszkiewicz, PE (Technical Access Leader)
Brad C. Croop, PE (Technical Access Inspector)