NE 45th St Viaduct Project – East Approach Seismic Retrofit

What's happening now?

Construction is complete!

As of Summer 2018, crews completed seismic retrofits to the NE 45th St Viaduct, bringing to a close our 20-year effort to widen, reconstruct, and seismically retrofit this bridge! Thank you to everyone who was impacted by this work over the years. We are very appreciative of your patience to make the NE 45th St Viaduct a more seismically resilient bridge that can better serve the transportation needs of a growing Seattle. 

We are committed to improving and maintaining our bridges throughout Seattle. Visit the SDOT Bridges webpage to learn more about our current bridge projects. 

Project Description

The NE 45th St bridge is an important connection between the University District and University Village, and a key emergency route. It was built in 1938 and over the years, we’ve widened and reconstructed segments of the viaduct.

In the early 1990s, we implemented a program to evaluate and retrofit bridges that were identified as seismically vulnerable. The NE 45th St viaduct’s east approach was identified as one of those seismically vulnerable bridges, which resulted in the main span being seismically retrofitted in the mid-1990s and the full reconstruction of the west approach in 2010. Following these retrofits, the NE 45th St Viaduct's east approach began construction for seismic improvements in Spring 2018. By retrofitting the east approach of the NE 45th St Viaduct, the entire bridge is now more structurally resilient to seismic events. 

The impact of retrofitting the east approach was smaller and more localized than the reconstruction of the west approach. The completed seismic retrofit improvements to the east approach included:

• Placement of steel jackets on the bridge columns
• Installation of longitudinal and transverse restraints underneath the bridge
• Construction of in-fill walls between existing columns
• Construction of a new catcher bent along one of the existing expansion joints
• Restoration of disturbed landscaping  

Seismic retrofits completed underneath the east approach of the NE 45th St Viaduct

Restored disturbed landscaping adjacent to the walking path in the east approach

New steel jackets on the bridge columns

Project Budget & Funding

Total project budget: $2 million

Funding Sources:

• Federal funds (FHWA)
• Local funds (Street Vacations)

Project Schedule*