N Northlake Way Retaining Wall
Retaining wall construction, paving, sidewalk construction
Updated: July 25, 2022
What’s happening now?
We completed alternatives analysis and conceptual design in late 2019 and met with adjacent property owners via an in-person socially distanced session in August 2020, where we shared information about the conceptual project design, funding, the schedule, and the potential impacts of construction. We are currently working toward 30% design and expect to reach this milestone by the end of 2022. In the coming months, we will be doing investigations to locate utilities and taking samples to determine the condition of the soil in the project area.
During the early design process, we will be reaching out to business owners and community members to share information and to gather input.
Overview
The 432-ft long Northlake Retaining Wall supports the adjacent N Northlake Way including public utilities and arterial serving northeast Seattle. Based on traffic counts, we estimate that approximately 1,000 vehicles travel this segment of N Northlake Way on an average weekday and know that wall provides access to multiple private lakeside businesses along Lake Union. .
In 2018, SDOT installed fencing and restricting parking adjacent to the retaining wall restricted parking at the top of the wall to reduce load on the wall. The existing structure needs repairs to strengthen it and to address significant seismic hazards associated with the historic fill and liquifiable soils located adjacent to and beneath the existing wall.
Projects of this type and scale provides opportunities to cost-effectively update street designs to promote safety, update and replace aging infrastructure (primarily utilities), and coordinate with other projects. They also provide an opportunity for community engagement to ensure feedback is gathered and incorporated into the final design.
Community Engagement
We will be reaching out to the community to solicit ideas and input for improvements that will serve the traveling public that uses this segment of N Northlake Way corridor.
While public safety remains the primary purpose of the planned wall replacement, this project will also include other measures and features including:
- Sidewalks
- Pedestrian safety improvements
- Drainage improvements
- Street Parking
- Paving
- Utility relocation and replacement
Planning project map
Planning design concepts
We are currently in the planning phase of this project where we gather information, create concepts, and gather input from stakeholders, business owners and members of the community. As we gather input, we will continue to adapt plans and concepts to represent community-informed designs moving forward.
Based on our 2019 study, our leading concept for wall replacement relies upon significant stabilization and strengthening of soils behind the existing retaining wall using grout columns founded on hard glacial till. Installation of the ground improvements would require excavation within most of the right of way behind the wall. Upon completion, these ground improvements, coupled with a replacement cut-off wall along Lake Union would provide a resilient base for replacement of utilities in the right of way and complete streets elements like new sidewalks, parking, travel lanes and other desirable features.
The elevation and plans above are conceptual and not to scale.
Schedule
This is our anticipated project timeline for the N Northlake Way retaining wall:
Fall 2020 - summer 2022
Planning
Fall, 2022
Begin design
Spring, 2024
Begin construction (subject to funding)
The three stages of an SDOT project
-
Planning
What we do: Collect data, review plans and gather community experiences to define options. -
Design
What we do: Share updates as more details are known. -
Construction
What we do: Provide construction schedules, expected impacts, and a contact for questions.
Funding
This project originated through SDOT's Retaining Walls program and is now funded through design using local funding sources as appropriated by City Council. We continue to work to secure construction funding, including pursuing federal funding opportunities such as FEMA's Building Resilient Infrastructure and Communities (BRIC) grant.
Project Materials
To view a PDF of project-related materials, please click on the links provided below.
Planning Phase
- Alternatives analysis (November 2019)
- Conceptual design report (November 2019)
We're committed to building a productive, inclusive, and collaborative relationship with all who live, work, or travel in the project area. Please contact us with any questions.
Phone: 206-375-5636
Email: NorthlakeWall@Seattle.gov
Community Outreach Lead
Darrell Bulmer
Project Manager
Mike Ward
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