Replacing the Alaskan Way Viaduct has been a top priority for Washington state and the City of Seattle since the Nisqually earthquake damaged the structure in 2001. The following is a summary of how this effort has progressed.
To learn more, read the Project History Report (pdf 4.5 Mb), which was released in September 2009.
2002
- WSDOT and the City of Seattle consider a list of 76 replacement concepts and narrow the list to five alternatives for further consideration.
2004
- A Draft Environmental Impact Statement (EIS) includes evaluations of five alternatives: a rebuilt viaduct, a new aerial structure, a single-level cut-and-cover tunnel, a bypass cut-and-cover tunnel, and a six-lane surface boulevard.
- WSDOT, the City of Seattle, and the Federal Highway Administration select the cut-and-cover tunnel as the preferred alternative. The rebuild alternative is carried forward as an alternate option, if it is determined there is not enough funding for the tunnel.
2005
- Engineers complete further design work on the tunnel and rebuild alternatives.
2006
- The “rebuild alternative” is renamed the “elevated structure alternative” to better represent changes made to the design since the draft EIS was published.
- The Washington State Legislature passes legislation requiring an expert review panel to study the feasibility of both alternatives.
- As a result of the review panel’s report, WSDOT updates cost estimates for both alternatives to adjust for rising inflation rates and worldwide increases in construction material costs.
- The legislature directs the Seattle City Council to adopt an ordinance stating their preferred option. The council reaffirms its support of a tunnel.
- WSDOT releases a Supplemental Draft EIS to provide more detailed information on the two alternatives and potential construction plans.
- Governor Gregoire calls for a vote by the citizens of Seattle.
2007
- An advisory vote is held in Seattle, calling for an up-down vote on a surface-tunnel hybrid and an elevated structure. Both receive a majority “no” vote.
- WSDOT, King County and the City of Seattle move forward with critical safety and mobility improvements to the Alaskan Way Viaduct. These projects will replace about half of the viaduct, and will fit with any chosen design for the central waterfront section.
- WSDOT begins a collaborative process with city and county officials to determine the replacement for the central waterfront section of the viaduct.
2008
- In April crews finish reinforcing four viaduct columns between Columbia Street and Yesler Way, where the structure had settled several inches since the Nisqually earthquake.
- In September we begin relocating electrical lines that are attached to the viaduct's south end.
- WSDOT, King County, and the City of Seattle work together to find a solution for the viaduct's central waterfront section. They develop and evaluate eight draft scenarios, or comprehensive solutions, which cover a range of options, from a smaller road along the central waterfront and significant investments in transit and surface streets, to bypass roadways with fewer transit and surface street investments. These options are narrowed down to two hybrid scenarios - an “I-5/surface/transit” alternative and an “SR 99 elevated bypass” alternative. The hybrids package together elements from the previous eight scenarios, including improvements to I-5, surface streets and transit.
2009
- In January Governor Gregoire, King County Executive Sims, and Seattle Mayor Nickels recommend replacing the central waterfront section of the Alaskan Way Viaduct with a deep bored tunnel beneath downtown, a new waterfront surface street, transit investments, and downtown city street and waterfront improvements.
- The Washington State Legislature passes legislation in April that endorses the bored tunnel and provides the budget authority necessary for its construction. Governor Gregoire signs the bill into law in May.
- In July crews begin relocating utilities in preparation for road and bridge construction to replace the viaduct's south end.
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