Alaskan Way Viaduct and Seawall Replacement Program Update

Amanda Sparr, WS DOT

Portal Area Design Guidelines Complete

The proposed SR 99 bored tunnel, part of the Alaskan Way Viaduct and Seawall Replacement Program, would have a dramatic effect on the neighborhoods where it comes to the surface, such as South Lake Union. That is why the program team has spent several months developing design guidelines for the 

Design concept: north entrance to the proposed SR 99 bored tunnel (looking south).  Credit: Courtesy of WSDOT

tunnel’s connection to Aurora Avenue, its operation building and the new street connections across Aurora Avenue and along Sixth Avenue N.

In May 2010, the program team briefed the South Lake Union Chamber of Commerce and South Lake Union Community Council on the portal area design guidelines. Developed with input from the Seattle Design Commission and stakeholders, the guidelines set the design goals and vision for the portal area. They state that the tunnel portal and tunnel-related structures should:

• Provide for the safety and comfort of pedestrians, bicyclists, and transit, freight and other vehicles.
• Reinforce the sense of place and give structure and orientation to the urban experience.
• Contribute positively to the fabric of the city and the unique qualities of adjacent neighborhoods.
• Contribute to the sustainability of the urban environment.

The guidelines have been incorporated into the SR 99 Bored Tunnel alternative design-build request for proposals, issued in May. The objectives of the design guidelines will have to be incorporated by the potential contractors as they develop their tunnel proposals. The tunnel and portal designs will be further reviewed in the second Supplemental Draft Environmental Impact Statement for the project, which will be available for public review this fall.

Members of the program team are always available to brief community groups. If you would like to schedule a briefing, please contact us at mailto:viaduct@wsdot.wa.gov or call 1-888-AWV-LINE (298-5463).

Upcoming Construction

South of downtown, crews will soon begin major construction on the S. Holgate Street to S. King Street Viaduct Replacement. This project will remove almost half of the viaduct structure in 2012. The new side-by-side roadway will improve mobility along SR 99 and meet current seismic design standards.
Construction this year won't affect traffic on SR 99, but there will be impacts to parking and surface street traffic in the area west of Qwest and Safeco fields.  Visit the project website for details.

Events & More Information

We’re on the ground in your neighborhood: look for the Alaskan Way Viaduct and Seawall Replacement Program booth at the Cascade Farmers Market on June 24 and the South Lake Union Block Party on August 15.

For further program information or to submit questions or comments, please visit www.alaskanwayviaduct.org.