Project Overview
The Kuparuk River on the North Slope of Alaska traverses a floodplain nearly 2 miles wide, with dramatic floods and substantial ice floes annually affecting the area. Modern resource development in the region requires reliable infrastructure to support large vehicles, previously served by a gravel road prone to seasonal disruptions. For nearly 20 years, spring road closures lasted anywhere from six to eight weeks due to washouts and reconstruction. PND designed a lasting solution that would decrease yearly closures of the critical road to a maximum of one week and eliminated the need for annual reconstruction.
PND designed two innovative submersible bridges with ice-breaking piers and an approach roadway system at the Kuparuk River’s east and west channels, allowing passage of annual floods and ice floes while saving approximately $10 million over the potential cost for elevated bridges over the river. PND overcame multiple atypical design and construction challenges, such as extreme environmental conditions, design vehicle weights approaching 4 million pounds, impact loading from river ice 5 feet thick, and discontinuous permafrost soil conditions.
PND has conducted annual bridge inspections of the crossings for the last two decades and recently upgraded the east channel crossing in response to increased flow.
Our Role
- Civil Engineering: designed two submersible bridges with heavy steel pile bents, icebreakers, and a robust steel multigirder superstructure, including annual inspections to ensure reliability
- Geotechnical Engineering: ensured our bridge designs accommodated the cold region site’s discontinuous permafrost soil conditions
- Arctic Engineering: engineered a resilient solution to withstand the Arctic site’s extreme cold and heavy seasonal ice floes
- OPEN CELL SHEET PILE: designed OCSP bridge abutments to accommodate oversized loads
Comprehensive Design for All-Season Bridges
PND designed the 150-foot and 210-foot submersible bridges to withstand severe environmental forces and extreme load demands. The bridges feature concrete-encased, all-steel multigirder superstructures that can withstand over 1.5 million pounds of force every year from seasonal river ice. PND incorporated heavy steel pile bents, using specialized techniques to drive the piles into the frozen riverbed. PND engineered the bridges to support massive resource development vehicles on the North Slope, including 4-million-pound off-road modules and drill rigs with 1.4-million-pound axles. The bridges include PND-proprietary OPEN CELL SHEET PILE™ (OCSP™) bridge abutments and removable railings to accommodate oversized loads.
PND provided design and permitting packages, inspection services, and office support to the field during construction. Our ongoing inspections and targeted upgrades ensure the bridges continue to support uninterrupted crossings of the Kuparuk River.
Saved
by constructing submersible bridges rather than elevated bridges
Temperature Ranges
the bridges endure between -60°F winter lows and 85°F summer highs
Pounds
vehicle load capacity on the bridges
