Portageville project winner of ENR Award
Norfolk Southern Railway replaced its aging wrought iron truss railway viaduct built in 1875 over the Genesee River Gorge to meet the demands of modern-day freight rail transportation.
The new $75 million spandrel-braced steel arch railroad single-track bridge in Letchworth State Park is now nearly 965 feet in length including a 485-foot-long arch and stands 235 feet over a scenic gorge. As the first true arch bridge built for the railroad industry since the 1940s, this bridge replacement project has been named the recipient of ENR’s New York Highway/Bridge Award of Merit.
The new bridge, built on an adjacent alignment 75 feet south of the old one, is a single-track crossing with a ballast-filled concrete deck. The main span is a 483-foot-long arch and there are three 80-foot-long girder span approaches on each end. It opened December 2017.
The prior truss bridge had 13 open-deck spans totaling 819 feet, carrying a single track 235 feet above the Genesee River. It was one of the nation’s oldest rail bridges and an important connector on the Southern Tier line between Binghamton and Buffalo. It remained active 75 feet north of construction of its replacement. Meanwhile, the site was historically and environmentally sensitive with the presence of an endangered species and the ruins of a Civil War-era hotel that required preservation, as did parts of the old iron bridge.
American Bridge requested Hayward Baker design and install a temporary soldier pile and lagging wall for excavation support of the existing railway consisting of 30 soldier piles and 38 tiebacks to support a 30-foot-excavation; 208 rock-socketed 12-inch-diameter micropiles each with a 118.5-ton capacity for the new bridge foundations; and two deadman anchor blocks each consisting of 24 temporary 1.75-inch tieback anchors (each 240 kips) installed at each abutment 100 feet to bedrock with a 26-foot rock socket to support the arches during the assembly of the bridge.
A key link in Norfolk Southern’s route to New England from the west, the new bridge carries about a dozen trains per day and services 1,100 customers with shipping points across 23 states in the eastern half of the US. The new span allows the owner to run industry-standard 286,000-lb-cars up from the current 273,000 lb limit. Trains can now move across the bridge at 30 mph up from 10 mph on the old span.
- Application: deep foundations, earth retention & shoring
- Technique Used: micropiles, soldier piles & lagging, anchors
- Market: Infrastructure – Railway
- Owner: Norfolk Southern Railway
- Main Contractor(s): American Bridge
- Engineer: Modjeski and Masters, Bergmann
- Owner’s Representative/Construction Manager: Bergmann Associates
- Geotechnical Subconsultant: Golder Associates
- Main Arch Bridge Fabricator: Canam Bridges