Hayden Island Ground Improvement
Ground testing work for replacement Interstate Bridge construction.
The Interstate Bridge Replacement (IBR) program team will test soil strengthening methods at the Oregon Department of Transportation (ODOT) former motor carrier permitting site on Hayden Island from November 2025 through February 2026. The findings from the testing will help determine how different ground improvement methods perform to help strengthen the soil beneath IBR Program investments.
Why is the testing happening?
The existing Interstate Bridge is considered functionally obsolete and seismically vulnerable, with one bridge span now 108 years old and the other 65 years old. Supported by timber piles in liquefiable soils, the structure is more at risk of collapse than any other critical transportation facility in the area. This work will provide data to contract bidders, designers and constructors as they plan and consider cost effective soil stabilization. Information collected from this work will help determine which methods could best stabilize the ground at this location so program improvements can better withstand an earthquake.
When will work begin, and how long will it last?
Keller North America, a contractor working for ODOT began the testing work in November 2025 and will continue through February 2026. The field work schedule is subject to change due to inclement weather events or unforeseen operational issues.
When and where will the work take place, and will it affect traffic?
Fieldwork will occur at the Oregon Department of Transportation (ODOT) former motor carrier permitting property on Hayden Island and will happen during daytime hours. People who live and work near the testing area will hear construction noise from drilling activities. If you experience any noise-related concerns, please call ODOT’s 24/7 Noise Hotline at 503-294-2125.
Motor vehicle traffic will not be disrupted. This will take place entirely on ODOT property, located at the corner of North Hayden Island Drive and North Center Avenue, and the work will be visible from Interstate 5 and the southbound off-ramp to Hayden Island.
A pedestrian and bicycle path connecting North Center Avenue with the Interstate Bridge will be closed throughout the project and a temporary path will be constructed outside of the work zone to maintain access. The image at the top of the page shows an aerial view of the work zone.
What are they testing?
The seismic vulnerability of the current Interstate 5 Bridge stems from its foundation: It is supported by timber piles in liquefiable soils. To identify the appropriate approach to addressing this, engineers are testing different ground stabilization methods to determine how they perform in preparation for construction of program investments. The ODOT site on Hayden Island was chosen because it has similar soil characteristics as the North Portland Harbor and the north shoreline of Hayden Island, which have loose soil.
Engineers are testing the effectiveness of three methods for strengthening the loose soil:
Jet grouting: Involves using high-velocity jets to mix the existing soil (in place) with grout and strengthen the ground.
Stone columns: Involves vibrating and compacting mechanisms to install stone columns and strengthen the ground.
Deep soil mixing: Uses a drill to mix cement with existing soil (in place) to strengthen the ground.
What are the next steps?
Findings from this work will be shared with the designers as part of the construction contracting bid materials to better inform design and construction methods that would withstand an earthquake.