The $3.1-billion extension of Sound Transit's Light Rail Federal Way Link system in the Seattle, WA metropolitan area will transform the way that residents travel for work and leisure purposes. Under construction since 2019, the extension will be 7.8 miles long and will feature three new stations, creating a faster alternative route for those traveling between the cities of SeaTac and Federal Way in Washington state. Completion is estimated to be late 2026 and will serve an estimated 37,000 daily riders by 2035. Sound Transit will upgrade city streets impacted by the project. Improvements include new sidewalks, street lighting, drainage, and undergrounding of overhead utility lines. 

Developing a new long-span bridge design over an unstable soil area is a challenge, however Kiewit Infrastructure West Company (Kiewit) the design-build contractor wisely hired Subsurface Construction Company (Subsurface) to facilitate the foundation and temporary work required for this project. Subsurface is a leading design-build geotechnical specialty soil nail, soldier pile, and micropile contractor that develops and constructs ground shoring and underpinning solutions custom designed to fit each job, making them the perfect choice. 

Approximately 4 miles of the line extension are elevated with 188 columns. Of those, over 130 are complete, as well as 50 girder spans. Drilled shafts support the columns and girder spans and as of early 2024, 121 drilled shafts for constructing elevated guideway and station facilities have been completed. To relieve congestion, improve transit performance, and enhance mobility along a busy portion of southern King County, Subsurface Construction is currently constructing a retaining wall built to withstand any seismic disruptions that will support a crucial 1,100-foot-long bridge going over a 500-foot span of unstable soil along the railway path. To help with this critical fitting, Subsurface reached out to their International Construction Equipment, Inc. (ICE®) regional drilling experts who recommended the Comacchio MC-20A Drill Rig for drilling the installation sites for strand anchors. Subsurface crew grouted them in with a Tecniwell GMP822 fully automated grout plant. These underground drilled shafts are about 10' (ft) in diameter with a depth ranging from 80' - 130' (ft), dependent on soil conditions, and will serve as foundations for the above-ground columns. Temporary work will support the wall as they excavate, ensuring stability and safety while minimizing the excavation area, keeping the sides of deep excavations stable, and ensuring that movements will not cause damage to neighboring structures or to utilities in the surrounding ground. 

International Construction Equipment, Inc is proud to have once again supplied Subsurface with the equipment needed to help them complete the foundation that will provide a fast, reliable, and environmentally friendly transit option for commuters throughout the Seattle region. Call your nearest ICE® Sales Representative today to learn how a Comacchio drill rig can ensure success on your next project! 

Learn more about the Comacchio MC 20A and other fully articulated multipurpose rigs of the Comacchio fleet. 

Media Contact-    
Pollyanna Cunningham, MA, MBA    
Vice President Marketing, Brand and Media Relations  

Vice President IT and IT Comm 
ICE® - International Construction Equipment, Inc    
Office - 704-821-8200    
Email - marketing@iceusa.com