“We are pleased to have effectively delivered preconstruction services and successfully negotiated all the construction phase contracts,” said Derek Betts, Granite Vice President of Regional Operations. “As a partner with the FHWA and NPS, we look forward to building this critical bridge and providing the public with access to the western half of the park that has been cut off by a landslide since 2021.”
The Polychrome Area Improvements project is at the Pretty Rocks Landslide, which intersects Denali Park Road near its midpoint at Mile 45.4. The project scope includes construction of an approximately 475-foot-long single-span steel truss bridge to span the active landslide. Supporting the bridge and improving ground conditions is a combination of earthwork, micro piles, rock anchors, soil nails, precast/post tensioned concrete abutments, and thermosyphons. Thermosyphons are part of a passive heat exchange system designed to prevent permafrost from thawing and creating instability.
Construction of the Polychrome Area Improvements project began in 2023 with mobilization, development of a worker camp, pioneering access across a landslide, blasting, and mass earthwork. Work planned for the 2024 season includes completion of mass earthwork, construction of the bridge abutments, installation of a temporary launching system, and partial erection of the structural steel bridge. Bridge erection will continue through 2025, along with launching of the structure to span the landslide. For the 2026 season, construction includes setting precast bridge approaches, building a retaining wall, installing thermosyphon condensers, coating the bridge deck, and demobilization.
