Strengthening Colorado’s Mountain Gateway: ECI at the Eisenhower-Johnson Memorial Tunnel
The Eisenhower-Johnson Memorial Tunnel, spanning beneath the Continental Divide near Keystone, Colorado, is one of the highest vehicular tunnels in the world and a vital link along Interstate 70. More than 11 million vehicles travel through its twin bores each year, making its structural integrity and safety critical for both Colorado residents and the countless visitors who rely on it.
Engineering & Construction Innovations, Inc. is leading a unique and highly technical rehabilitation effort inside the tunnel’s plenum—the structural space behind the tunnel liner. The work focuses on mitigating water intrusion, a persistent challenge in high-elevation environments where freeze and thaw cycles can cause significant damage to roadway surfaces and supporting infrastructure.
Innovative Platform Design
To safely access and repair the plenum liner, the team designed and installed a 2,100-foot suspended work platform. Supported by concrete and rock dowel hanger rods, aluminum beams, and wood decking, the system eliminates construction loads on the precast concrete roof of the active transportation tunnel below. This design not only prioritizes safety but also ensures uninterrupted use of the tunnel by the traveling public.
Precision Grouting Operations
Once the platform was in place, crews began drilling hundreds of three-stage grout holes throughout webound tunnel. Using an ultrafine cement and neat cement grout, injected at pressures up to 440 PSI, the team is filling voids behind the structural tunnel liner and stabilizing rock fractures extending as far as 20 feet outside of the tunnel. These grouting operations are critical to maintaining the long-term durability of the liner and roadway.
A Project of Statewide Importance
With work scheduled for completion in October 2025, this effort represents a major investment in the reliability of Colorado’s mountain transportation system. By stabilizing the rock and the tunnel’s structural liner, this project will extend the life of this critical infrastructure and ensure safe passage for millions of drivers in the decades to come.
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About ECI
ECI is a premier engineering and construction firm specializing in geotechnical construction, water resources infrastructure, hydro/marine construction, specialty construction, and tunnels & shafts. For 25 years, we’ve delivered high-quality, sustainable solutions tailored to our clients’ unique needs. Learn more about our Leadership Team and our Mission, Vision & Values in the About section.