Case Study: Unanticipated Frozen Ground Increases Costs in Alaska Highway Project (2017)

Project Overview
• Name: Dalton Highway Upgrade
• Location: Alaska
• Year: 2017
• Project Size: $180 million
• Scope: Highway upgrade with embankments and bridge foundations
• Lead Agencies/Contractors: Alaska DOT /

Category of the Issue, Problem, or Challenge
• Geotechnical
• Differing Site Conditions
• Weather-Related

Summary of the Issue, Problem, or Challenge
Frozen permafrost layers were found deeper and more variable than expected, complicating excavation and foundation works.

Root Cause Analysis

• Incomplete permafrost mapping and thermal monitoring during site investigation.
• Underestimation of thaw settlement risks and frost heave potential.
• Lack of appropriate cold region construction methods in initial planning.

Impacts Due to the Issue, Problem, or Challenge

• Delay of 5 months due to redesign and implementation of ground thermal control measures.
• Significant cost overruns related to insulation and thermosyphon installation.
• Long-term maintenance concerns for foundations.

Corrective Actions Taken

1. Conducted detailed permafrost and thermal regime studies.
2. Incorporated thermosyphons and insulation systems into foundation design.
3. Modified construction schedule to avoid thaw seasons.
4. Enhanced training on cold region construction practices.

Lessons Learned

• Cold region projects require detailed permafrost investigations and monitoring.
• Designs must mitigate thaw settlement and frost heave.
• Seasonal timing of construction critical to success.

Audit & Prevention: Project Control Questions to Ask on Future Projects to Help Control the Situation

• Have permafrost conditions been thoroughly mapped and monitored?
• Are foundation designs adapted for thaw and freeze cycles?
• Does the construction schedule avoid sensitive thaw periods?