8th Ave NW Bridge Seismic Improvements Project

Updated: October 2, 2019

What's happening now?

Our team has finalized the design for the 8th Ave NW Bridge seismic retrofits and is in the process of selecting a contractor. Once a contractor has been selected construction is anticipated to begin as soon as winter 2019 and last approximately 5-6 months

As we finalized the design it became clear we could not safely maintain bicycle and walking access during construction. In order to complete this work safely and efficiently, the bridge will be fully closed for the duration of construction. We appreciate your flexibility as we prioritize the safety of neighbors and crew members.

Last winter we asked neighbors to participate in an online survey  to help us understand how they currently use the 8th Ave NW bridge and to provide feedback on the proposed construction approach. We are incorporating this feedback and considering factors such as technical feasibility, cost, and efficiency as we finalize the construction approach and associated timeline. To stay up to date with the latest project information, sign up to join the project listserv. 

Project overview

Earthquakes could have a detrimental effects on Seattle's infrastructure. To address seismic risks to city infrastructure, the City of Seattle established a bridge seismic retrofit program to assess the seismic vulnerability of the City's bridges and to prioritize limited funding to reduce this transportation infrastructure vulnerability. 

As part of the Levy to Move Seattle, 16 bridges were selected for seismic retrofits, including the 8th Ave NW Bridge. The 8th Ave NW Bridge is an older bridge constructed in 1950 prior to the modernization of the seismic design code. Spanning a forested ravine and connecting different parts of the Broadview neighborhood, it carries both vehicular and pedestrian traffic. 

The planned seismic retrofits to the 8th Ave NW Bridge include several modifications to seismically strengthen existing bridge components and reduce the bridge's vulnerability to earthquakes. There will be construction equipment, noise, dust, and possible detours for the duration of the project to maintain a safe separation between people and the work site. 

Project Map

Map of 8th Ave NW Bridge

Schedule and construction*

  30% Design   Complete
  60% Design   Complete
  Final Design   Complete
  Construction begins   Winter 2019

 

*The schedule is subject to change. 

Once construction begins it is scheduled to last approximately 5-6 months.

To complete the work as safely and efficiently as possible the bridge will be closed to all traffic for the duration of construction. The planned traffic detour route will use nearby 3rd Ave NW to NW 137th St to access homes north of the 8th Ave NW bridge. The final detour route will be confirmed once a contractor is onboard and we are closer to the construction start date. We understand this closure will impact everyone who uses the bridge regularly and will do what we can to minimize impacts.

Once we have a contractor on board, we will have more information about the project timeline and construction impacts. We currently anticipate the following impacts:

  • Work in the public right-of-way near your home or business
  • A temporary full bridge closure with detours for people walking, biking, and driving
  • Occasional traffic or lane restrictions, including side street closures
  • Temporary on-street parking restrictions, with "no park" signs placed 72 hours in advance
  • Detours for people walking, biking, and driving to get you safely around work zones
  • Typical construction equipment, materials, noise, dust, and activity in the work area
  • Typical weekday work hours are 7 AM - 5 PM, Monday through Friday

Funding

The total project estimate is $3 million and is funded through the Levy to Move Seattle. Approved by voters in 2015, the 9-year, $930 million Levy to Move Seattle provides funding to improve safety for all travelers, maintain our streets and bridges, and invest in reliable, affordable travel options for a growing city.

Get involved

We're committed to keeping you informed and working with neighbors to limit construction impacts to the extent feasible. Here are some more ways to get information about the project:

Materials

8th Ave NW Bridge survey summary (April 2019)

Project introduction and construction impacts letter (December 2018)