Project Location
Bridgeport,
WA
Client
U.S. Army Corps of Engineers via KRCI LLC
Market Sector
Project Type
- Power Generation
Project Disciplines
Project Highlights
- Conducted detailed soil, rock, and groundwater investigations using advanced drilling methods.
- Evaluated bedrock characteristics, permeability, and strength to support anchor system design.
- Developed recommendations for anchor pull-out capacity, displacement tolerances, and installation.
Project Description
The Chief Joseph Dam Boom Replacement project involved specialized geotechnical investigation and engineering to support replacement of the dam’s existing boom system. Working with KRCI LLC on behalf of the U.S. Army Corps of Engineers, our geotechnical team evaluated complex soil and bedrock conditions to inform the design and installation of new anchoring systems.
The investigation included subsurface exploration using both roto-sonic and diamond core drilling equipment, with detailed documentation of soil, rock, and groundwater conditions. Laboratory testing evaluated soil gradation, moisture content, Atterberg limits, shear strength, compressibility, and corrosivity; bedrock samples were evaluated for unit weight and unconfined compressive strength, while field testing assessed bedrock permeability and rock mass characteristics.
The team used these findings to evaluate soil and rock adhesion, anchor pull-out capacity, and anchor displacement under loading conditions. Recommendations were developed for anchor system installation and construction, with the findings documented in a comprehensive geotechnical report. Ongoing consultation and plan review were also provided to address geotechnical considerations throughout design and construction.
Work performed by Nelson Geotechnical Associates, Inc., now part of MacKay.