Cone Penetrometer Test on Seattle's Pier 62
Enjoying live music and performances on the waterfront with ferries crossing in the background was once an annual summer tradition in Seattle. Piers 62 and 63, just north of the Seattle Aquarium, were home to the well-loved Summer Nights at the Pier and other events, but have been dormant recently because of the deteriorating condition of the aging twin structures.
Fast forward to the present, and Aspect is helping Seattle’s Department of Parks and Recreation revive the dream of hosting entertainment on the waterfront. As part of the Seattle Department of Transportation team, we have been performing geotechnical support for the reconstruction of Pier 62. Our geotechnical recommendations will inform design of the new pier’s foundations, creating a strong platform upon which to build a park that will reintroduce Seattle to Elliott Bay.
Before we can advise on how the foundations should be designed, we need to know what’s going on underground. These pictures, taken by Senior Staff Geotechnical Engineer Spencer Ambauen, are from our recent field work, where we conducted a Cone Penetrometer Test (CPT) to investigate the soils below the pier. CPTs are best suited to evaluate the types of loose granular and soft cohesive soils we expected to find there. Data collected from the CPT will inform the geotechnical analyses for the pier, such as liquefaction potential.
Cone Penetrometer Ready to Deploy
The team had to navigate around and cut through the existing structure to get the CPT through the water and soil layers. Due to the aging pier’s strict weight limits, we had to be cautious with what kind of rig we used. The skid rig shown here was light enough to meet the requirements and still advance the CPT through the upper soils.
This last picture looks down at the project area from Seattle’s Great Wheel. From that height, it’s exciting to imagine what the future will bring for the Piers. For more on plans for the Seattle waterfront, visit waterfrontseattle.org.
