View source for Alaskan Way Viaduct

{{Short description|Former elevated highway in Seattle, Washington}}
{{About|the former viaduct|its replacement|Alaskan Way Viaduct replacement tunnel}}
{{Use American English|date=January 2025}}
{{Use mdy dates|date=February 2019}}
{{Infobox road
|state=WA
|type=SR
|route=99
|name=Alaskan Way Viaduct
|map={{maplink|frame=yes|plain=yes|frame-align=center|frame-width=290|frame-height=310|frame-lat=47.599|frame-long=-122.341|zoom=13|type=line|raw={{Wikipedia:Map data/Wikipedia KML/Alaskan Way Viaduct}}}}
|map_custom=yes
|map_notes=A map of [[downtown Seattle]] with the Alaskan Way Viaduct highlighted in red and older demolished sections highlighted in pink
|length_mi=2.2
|length_round=1
|length_ref=
|length_notes=
|established={{Start date|1953|4|4}}
|decommissioned=January 11, 2019
|allocation={{jct|state=WA|SR|99}}
|direction_a=South
|terminus_a={{jct|state=WA|SR|99|name1=Marginal Way}} in [[Industrial District, Seattle|Industrial District]]
|junction=
|direction_b=North
|terminus_b={{jct|state=WA|SR|99|name1=[[Battery Street Tunnel]]}} in [[Belltown, Seattle|Belltown]]
|counties=[[King County, Washington|King]]
}}

The '''Alaskan Way Viaduct''' ("the viaduct" for short)<ref>{{Cite web|url=https://www.shermanstravel.com/advice/how-to-spend-a-perfect-day-on-the-seattle-waterfront|title = The Seattle Waterfront: What to do in One Day &#124; ShermansTravel}}</ref><ref>{{cite web| url = https://www.spokesman.com/blogs/down-earth/seattle/| url-status = dead| archive-url = https://web.archive.org/web/20200609092412/https://www.spokesman.com/blogs/down-earth/seattle/| archive-date = 2020-06-09| title = Down To Earth seattle archive {{!}} The Spokesman-Review}}</ref><ref>{{Cite web|url=https://www.antonellapavese.com/2019/01/bye-bye-alaskan-way-viaduct/|title = Bye Bye Alaskan Way Viaduct|date = January 20, 2019}}</ref> was an [[elevated freeway]] in [[Seattle]], Washington, United States, that carried a section of [[Washington State Route 99|State Route 99]] (SR 99). The double-decked freeway ran north–south along the [[Central Waterfront, Seattle|city's waterfront]] for {{convert|2.2|mi|km}}, east of [[Alaskan Way]] and [[Elliott Bay]], and traveled between the [[West Seattle Freeway]] in [[SoDo, Seattle|SoDo]] and the [[Battery Street Tunnel]] in [[Belltown, Seattle|Belltown]].

The viaduct was built in three phases from 1949 through 1959, with the first section opening on April 4, 1953. It was the smaller of the two major north–south traffic corridors through Seattle (the other being [[Interstate 5 in Washington|Interstate 5]]), carrying up to 91,000 vehicles per day in 2016.<ref name="viaduct_project">[http://www.wsdot.wa.gov/projects/Viaduct/ WSDOT Projects: Alaskan Way Viaduct and Seawall Replacement]</ref> The viaduct ran above Alaskan Way, a surface street, from S. Nevada Street in the south to the entrance of Belltown's Battery Street Tunnel in the north, following previously existing railroad lines.

The viaduct had long been viewed as a barrier between downtown and the city's waterfront, with proposals to replace it as early as the 1960s. Questions of the structure's seismic vulnerability were raised after several earthquakes damaged similar freeways in other cities, including some with the same design as the viaduct. During the [[2001 Nisqually earthquake]], the Alaskan Way Viaduct suffered minor damage but later inspections found it to be vulnerable to total collapse in the event of another major earthquake, necessitating its replacement or reinforcement.{{citation needed|date=July 2025}}

The state and city governments considered several options, including a rebuilt elevated structure, a surface boulevard, and [[cut-and-cover tunnel]], but could not compromise on a final choice. A deep-bored tunnel was selected in 2009 and the southern section of the viaduct was demolished in 2011 and replaced with a six-lane, single-deck freeway that travels through the SoDo industrial area.<ref>{{cite news |last=Gutierrez |first=Scott |title=Alaskan Way Viaduct closure, demolition begin |url=http://www.seattlepi.com/local/transportation/article/Countdown-to-the-Alaskan-Way-Viaduct-closure-2228936.php#page-1 |work=seattlepi.com |access-date=November 25, 2011 |date=October 22, 2011}}</ref> Excavation of the [[State Route 99 tunnel|downtown bored tunnel]] by the [[tunnel boring machine]] "[[Bertha (tunnel boring machine)|Bertha]]" began in 2013 and was completed in 2017 after two years of delays. The viaduct was closed permanently on January 11, 2019, and the new tunnel opened three weeks later on February 4.<ref>{{Cite web |url=http://www.wsdot.wa.gov/Projects/Viaduct/About/Tunneling |title=Alaskan Way Viaduct - Tunneling |date=2018 |website=Washington State Department of Transportation |access-date=June 30, 2018 |archive-date=December 10, 2012 |archive-url=https://web.archive.org/web/20121210035623/http://www.wsdot.wa.gov/Projects/Viaduct/About/Tunneling |url-status=dead }}</ref><ref name="Lindblom">{{cite news |last=Lindblom |first=Mike |date=September 17, 2018 |title=Permanent closure of Alaskan Way Viaduct delayed until January |url=https://www.seattletimes.com/seattle-news/transportation/permanent-closure-of-alaskan-way-viaduct-delayed-until-january/ |work=The Seattle Times |access-date=September 18, 2018 |archive-url=https://web.archive.org/web/20180917204001/https://www.seattletimes.com/seattle-news/transportation/permanent-closure-of-alaskan-way-viaduct-delayed-until-january/ |archive-date=September 17, 2018 |url-status=live }}</ref> Demolition of the main viaduct deck began weeks later, and was completed in early 2020 with remaining demolition occurring at the southern approach ramp through 2020 as part of the Waterfront Seattle project.

==Route description==
[[File:Alaskan Way Viaduct from Great Wheel pano 2016.jpg|thumb|left|Clear panoramic view of much of the Alaskan Way Viaduct from Seattle's [[Seattle Great Wheel|Great Wheel]], with the [[Seattle Aquarium]] on Pier 59 in the foreground, in 2016]]
[[File:The Alaskan Way Viaduct.jpg|thumb|The Alaskan Way Viaduct, looking southeast from [[Victor Steinbrueck Park]]]]
[[File:Alaskanviaduct.jpg|thumb|255px|The Alaskan Way Viaduct seen from [[Elliott Bay]]]]

The Alaskan Way Viaduct was a double-decker freeway that traveled through [[Downtown Seattle]] and [[SoDo, Seattle|SoDo]] along the western waterfront facing [[Elliott Bay]].<ref name="NYT-Drive">{{cite news |last=Yardley |first=William |date=May 20, 2012 |title=Drive, They Said: Washington, Highway 99 |url=https://archive.nytimes.com/query.nytimes.com/gst/fullpage-9A00E0DD103DF933A15756C0A9649D8B63.html |work=[[The New York Times]] |access-date=December 30, 2018}}</ref><ref name="HL-1953">{{cite web |last=Ott |first=Jennifer |date=December 19, 2011 |title=First section of Seattle's Alaskan Way Viaduct opens on April 4, 1953. |url=http://historylink.org/File/9982 |work=[[HistoryLink]] |access-date=December 30, 2018}}</ref> The two highway decks each carried two to four lanes measuring as narrow as {{convert|9|ft|6|in|m}} wide, with northbound traffic on the upper deck and southbound traffic using the lower deck with a vertical clearance of {{convert|14|ft|m}}.<ref>{{cite news |last=Lindblom |first=Mike |date=November 28, 2001 |title=Proposed 11-foot lanes not new for commuters |url=https://archive.seattletimes.com/archive/20011128/11footlanes28m0/proposed-11-foot-lanes-not-new-for-commuters |work=The Seattle Times |access-date=December 30, 2018}}</ref><ref>{{cite news |last=Lindblom |first=Mike |date=April 29, 2015 |title=Lesson learned? Faster cleanup as truck loses load on Hwy. 99 |url=https://www.seattletimes.com/seattle-news/transportation/sb-alaskan-way-viaduct-closed-after-truck-loses-load/ |work=The Seattle Times |access-date=December 30, 2018}}</ref> The viaduct was {{convert|60|ft|m}} tall<!--also listed as 57 feet by other sources-->,<ref>{{cite news |last=Westneat |first=Danny |date=June 23, 2004 |title=Viaduct: vroom with a view |page=B1 |work=The Seattle Times}}</ref> had {{convert|3|ft|m|adj=mid}} concrete railings,<ref>{{cite news |last=Heilman |first=Robert |date=April 12, 1953 |title=Engineers Find Viaduct Railings Safe, So Relax—But Be Careful |page=60 |work=The Seattle Times}}</ref> and was supported by 400 columns spaced approximately every {{convert|51|ft|m}}.<ref>{{cite news |last=Lindblom |first=Mike |date=March 5, 2007 |title=Why a bigger viaduct? |url=http://old.seattletimes.com/html/localnews/2003601315_viaductbulk05m.html |work=The Seattle Times |access-date=December 30, 2018}}</ref><ref name="NYT-Johnson">{{cite news |last=Johnson |first=Kirk |date=December 21, 2018 |title=In Seattle, Remembering Ugly Highway As End Nears |page=A12 |url=https://www.nytimes.com/2018/12/21/us/seattle-alaskan-way-viaduct.html |work=The New York Times |access-date=December 30, 2018}}</ref>

SR&nbsp;99 formerly transitioned from a surface freeway to the double-decker elevated viaduct near South Holgate Street in SoDo, approximately {{convert|3|mi|km}} north of the [[First Avenue South Bridge]] and beyond an interchange with the [[West Seattle Freeway]] near [[Harbor Island (Seattle)|Harbor Island]].<ref>{{cite news |last=DeMay |first=Daniel |date=October 6, 2018 |title=65 years of the Alaskan Way Viaduct |url=https://www.seattlepi.com/local/transportation/article/Photos-65-years-of-the-Alaskan-Way-Viaduct-13284852.php |work=[[Seattle Post-Intelligencer]] |access-date=December 30, 2018}}</ref> The freeway then ran between the [[Port of Seattle]]'s Terminal 46 and the [[Coast Guard Station Seattle|Seattle Coast Guard Station]] to the west and the [[BNSF Railway]] container yard to the east. It passed a set of [[ghost ramp]]s near [[T-Mobile Park|Safeco Field]] that were originally planned to accommodate a freeway connection to [[Interstate 90 in Washington|Interstate 90]] that was never built.<ref>{{cite news |last=Kelly |first=Tom |date=February 19, 1984 |title=Did voters kill solution to snarls? |page=D8 |work=The Seattle Times}}</ref> Near [[CenturyLink Field]], SR 99 reached the terminus of the original (and post-2011) viaduct and the south portal of the future [[Alaskan Way Viaduct replacement tunnel|downtown bored tunnel]], using a set of diagonal ramps parallel to Railroad Way to reach the central section of the viaduct.<ref>{{cite web |date=April 2014 |title=Replacing the viaduct's south end |url=http://www.wsdot.wa.gov/Projects/Viaduct/Media/Default/Documents/SouthEnd_April2014.pdf |publisher=Washington State Department of Transportation |access-date=December 30, 2018}}</ref><ref name="google">{{google maps |title=Alaskan Way Viaduct |url=https://www.google.com/maps/dir/47.5964456,-122.3344205/47.6139341,-122.3477672/@47.6051199,-122.3499911,2963m/am=t/data=!3m2!1e3!4b1!4m2!4m1!3e0 |access-date=December 30, 2018}}</ref>

[[File:DETAIL VIEW OF NOTCH IN VIADUCT AROUND THE BUILDING. LOOKING NORTHWEST. - Alaskan Way Viaduct and Battery Street Tunnel, Seattle, King County, WA HAER WA-184-87.tif|thumb|right|A notch in the viaduct's railing at the [[Seattle Empire Laundry Building]] on Western Avenue]]

The viaduct expanded from four lanes to six lanes and turned northwest as it followed [[Alaskan Way]] and the city's waterfront on the west side of [[Pioneer Square, Seattle|Pioneer Square]]; the area underneath the viaduct was used for [[street parking]] between construction periods.<ref>{{cite web |date=October 10, 2018 |title=Go west, young road: Alaskan Way shifts west this weekend |url=http://www.wsdot.wa.gov/Projects/Viaduct/library/advisories-and-updates/alaskan-way-shifts-west-this-weekend |publisher=Washington State Department of Transportation |access-date=December 30, 2018}}</ref> It passed east of the state [[ferry terminal]] at [[Colman Dock]] and reached a set of ramps serving downtown traffic: the Columbia Street onramp to the southbound lanes and the Seneca Street offramp from the northbound lanes.<ref name="KIRO-Ramps">{{cite news |last=Banel |first=Feliks |date=December 14, 2018 |title=Sound familiar? Original Seattle viaduct had no ramps |url=http://mynorthwest.com/1061139/sound-familiar-original-seattle-viaduct-had-no-ramps/? |publisher=[[KIRO-FM|KIRO Radio]] |access-date=December 30, 2018}}</ref> The waterfront section of the viaduct was noted for its scenic views, which include Elliott Bay, the distant [[Olympic Mountains]], and the city's skyline.<ref name="NYT-Drive"/> Between the [[Seattle Aquarium]] and [[Pike Place Market]], the double-decker viaduct ended as SR&nbsp;99 split into a pair of side-by-side elevated lanes that traveled over the north portal of the [[Great Northern Tunnel|Great Northern railroad tunnel]] and under [[Victor Steinbrueck Park]].<ref name="google"/><ref>{{cite news |last=Kroman |first=David |date=September 27, 2018 |title=Local Native leaders want Pike Place totem poles removed |url=https://crosscut.com/2018/09/local-native-leaders-want-pike-place-totem-poles-removed |work=[[Crosscut.com]] |access-date=December 30, 2018}}</ref> SR&nbsp;99 then came to an interchange with Elliott and Western avenues, which marked the north end of the viaduct and the south end of the four-lane [[Battery Street Tunnel]].<ref>{{cite news |last=Lindblom |first=Mike |date=December 2, 2018 |title=Highway 99 tunnel FAQ: More questions and answers about the viaduct closing and tunnel opening |url=https://www.seattletimes.com/seattle-news/transportation/highway-99-tunnel-faq-more-questions-and-answers-about-the-viaduct-closing-and-tunnel-opening/ |work=The Seattle Times |access-date=December 30, 2018}}</ref><ref>{{cite web |date=November 7, 2017 |title=SR 99: Junction Western Avenue/Elliott Avenue |url=http://www.wsdot.wa.gov/mapsdata/tools/InterchangeViewer/pdf/SR099/099X032.pdf |publisher=Washington State Department of Transportation |access-date=December 30, 2018}}</ref> The Western Avenue crossing included a notch in the southbound railing of the viaduct, which was cut out to pass around a column of the [[Seattle Empire Laundry Building]].<ref name="Ott3">{{cite web |last=Ott |first=Jennifer |date=December 3, 2011 |title=Alaskan Way Viaduct, Part 3: Building the Viaduct |url=http://www.historylink.org/File/9978 |work=HistoryLink |access-date=December 30, 2018}}</ref>

The Alaskan Way Viaduct was one of two north–south freeways traversing Downtown Seattle, the other being [[Interstate 5 in Washington|Interstate 5]] to the east. Traffic volumes on the viaduct, measured by WSDOT in terms of [[average annual daily traffic]] in 2015, averaged approximately 91,000 vehicles south of Columbia Street and 71,000 vehicles between Columbia Street and Western Avenue.<ref name="WSDOT-AADT">{{cite web |date=April 15, 2016 |title=#99closure prep: Analyzing traffic patterns on the Alaskan Way Viaduct |url=http://www.wsdot.wa.gov/Projects/Viaduct/Status/Blog/99closure-prep-analyzing-traffic-patterns-on-the-alaskan-way-viaduct |publisher=Washington State Department of Transportation |access-date=January 6, 2019}}</ref> The viaduct formerly carried an average daily volume of 110,000 vehicles until the start of demolition in 2011.<ref name="WSDOT-AADT"/> The viaduct and other sections of SR 99 were designated as part of the [[National Highway System (United States)|National Highway System]] by the federal government and as Highway of Statewide Significance by the [[Washington State Legislature|state legislature]].<ref>{{cite web |year=2017 |title=State Highway National Highway System Routes in Washington |url=https://www.wsdot.wa.gov/mapsdata/travel/hpms/pdf/washington-2017-state-highway-nhs-list.pdf |publisher=Washington State Department of Transportation |access-date=January 6, 2019}}</ref><ref>{{cite web |date=July 26, 2009 |title=Transportation Commission List of Highways of Statewide Significance |url=https://www.wsdot.wa.gov/sites/default/files/2006/03/16/HSSlist2009mod2.pdf |publisher=[[Washington State Transportation Commission]] |access-date=January 6, 2019 |archive-date=July 24, 2013 |archive-url=https://web.archive.org/web/20130724190950/http://www.wsdot.wa.gov/NR/rdonlyres/50EC9EB9-DB3D-4823-B5D2-5348409FB8CE/0/HSSlist2009mod2.pdf |url-status=dead }}</ref>

==History==
{{expand section|date=December 2018}}
[[File:Alaskan Way Viaduct timelapse.webm|thumb|right|Video of a northbound drive on the viaduct in January 2019, just prior to its closure]]
[[File:Aerial of Alaskan Way Viaduct south of Downtown Seattle, 1960 (52474347222) (cropped).jpg|thumb|right|Aerial view of the Alaskan Way Viaduct and its southern extension in 1960]]

The Alaskan Way Viaduct was originally built to carry a section of [[U.S. Route 99 in Washington|U.S. Route 99]], the main north–south highway in Washington and along the U.S. [[West Coast of the United States|West Coast]]. The highway previously used downtown streets, but rising automobile congestion in the 1920s sparked proposals for a [[limited-access highway|limited-access]] [[bypass (road)|bypass]] of Seattle. An elevated roadway, placed along the waterfront's [[Alaskan Way|Railroad Avenue]] (later renamed Alaskan Way), was recommended by several city engineers in the latter part of the decade.<ref name="HAER2008">{{cite web |last=Sheridan |first=Mimi |date=January 2008 |title=HAER WA-184: Alaskan Way Viaduct and Battery Street Tunnel, Seattle, King County, Washington |url=http://lcweb2.loc.gov/master/pnp/habshaer/wa/wa0800/wa0830/data/wa0830data.pdf |work=[[Historic American Engineering Record]] |publisher=[[Library of Congress]] |access-date=December 30, 2018}}</ref> Plans for an elevated highway gained public support in the late 1930s and was approved for construction in 1947 using funds from the [[Federal-Aid Highway Act of 1944]].<ref name="Ott2">{{cite web |last=Ott |first=Jennifer |date=October 27, 2011 |title=Alaskan Way Viaduct, Part 2: Planning and Design |url=http://historylink.org/File/9951 |work=HistoryLink |access-date=January 1, 2019}}</ref><ref>{{cite news |date=June 30, 1938 |title=Alaskan Way By-Pass Asked |page=36 |work=The Seattle Times}}</ref>

Construction on the viaduct began in February 1950 and was completed in stages between 1953 and 1959. The central portion, from Railroad Way to Elliott Avenue, opened on April 4, 1953.<ref>{{cite news |date=April 5, 1953 |title=Alaskan Way Viaduct Opened To Traffic |page=1 |work=The Seattle Times}}</ref> It was connected to the Battery Street Tunnel the following year and a series of offramps and onramps to downtown in the 1960s. Additional ramps to University and Spring streets were included in design plans, but never built.<ref name="KIRO-Ramps"/> The southern section of the viaduct, linking to the [[Spokane Street Bridge]], was opened in September 1959.<ref name="HL-1953"/><ref>{{cite news |date=September 3, 1959 |title=Viaduct Extension Opened Officially |page=1 |work=The Seattle Times}}</ref>

The viaduct officially closed on January 11, 2019, attracting spectators and drivers who caused it to miss the 10&nbsp;p.m. deadline.<ref>{{cite news |last=Lindblom |first=Mike |date=January 11, 2019 |title=Goodbye, viaduct: The highway closes for good after 66 years on Seattle's waterfront |url=https://www.seattletimes.com/seattle-news/transportation/goodbye-viaduct-the-highway-closes-for-good-after-66-years-on-seattles-waterfront/ |work=The Seattle Times |access-date=January 11, 2019}}</ref><ref>{{cite news |date=January 11, 2019 |title=Seattle viaduct closure morphs into traffic party |url=https://www.king5.com/article/news/local/tunnel-effect/seattle-viaduct-closure-morphs-into-traffic-party/281-3329e48b-c66f-4b2d-ab76-78ad0f7ac63a |publisher=KING 5 News |access-date=January 11, 2019}}</ref> Demolition of the northbound ramp on Railroad Way began the following day in preparation for the excavation of pre-constructed ramps into the new tunnel.<ref>{{cite news |last=Crowe |first=Michael |date=January 12, 2019 |title=Crews demolish ramp to Seattle viaduct to prepare for future construction |url=https://www.king5.com/article/news/local/tunnel-effect/crews-demolish-ramp-to-seattle-viaduct-to-prepare-for-future-construction/281-6669c4bb-965f-414c-8180-e4611a0ae128 |publisher=KING 5 News |access-date=January 12, 2019}}</ref> Demolition was completed in stages between February and November 2019, using a section-by-section approach to avoid major disruptions. The last section to remain standing was near [[Pike Place Market]].<ref>{{cite news |last=Bushman |first=Sammi |date=November 19, 2019 |title=How to get your free piece of Seattle's Alaskan Way Viaduct |url=https://www.king5.com/article/news/local/the-viaduct-is-rubble-and-now-you-can-have-a-piece/281-c1db02b5-bc7a-4d6a-990c-c20bc3efddc2 |publisher=KING 5 News |access-date=November 20, 2019}}</ref><ref name="Times-Demolition18">{{cite news |last=Lindblom |first=Mike |date=December 5, 2018 |title=Seattle's big demolition spectacle: How crews plan to pulverize the Alaskan Way Viaduct |url=https://www.seattletimes.com/seattle-news/transportation/final-plans-outlined-for-demolition-of-alaskan-way-viaduct/ |work=The Seattle Times |access-date=November 20, 2019}}</ref>

==Replacement project==

===Earthquake concerns===

The [[1989 Loma Prieta earthquake]] destroyed the similarly designed [[Cypress Street Viaduct]] in [[Oakland, California]], with the loss of 42 lives.<ref>{{cite web |url=http://home.pacbell.net/hywaymn/Cypress_Viaduct_Freeway.html |title=Cypress Viaduct Freeway |archive-url=https://web.archive.org/web/20090707140502/http://home.pacbell.net/hywaymn/Cypress_Viaduct_Freeway.html |archive-date=July 7, 2009}}</ref>  The [[2001 Nisqually earthquake]] damaged the viaduct and its supporting Alaskan Way Seawall and required the Washington State Department of Transportation (WSDOT) to invest US$14.5 million in emergency repairs. Experts gave a 1-in-20 chance that the viaduct could be shut down by an earthquake within the next decade.<ref name="viaduct_project" /> Semi-annual inspections discovered continuing settlement damage from the Nisqually earthquake up until the viaduct was removed in 2019.

In 2001, the Alaskan Way Viaduct was considered for placement on the [[National Register of Historic Places]] by the [[Washington State Office of Archaeology and Historic Preservation]] for its historic qualities.<ref>{{cite news |last=Foster |first=George |date=January 14, 2002 |title=Getting There: Historic viaduct or hysterical idea—or both? |url=http://seattlepi.nwsource.com/transportation/54374_get14.shtml |work=Seattle Post-Intelligencer |url-status=dead |archive-url=https://web.archive.org/web/20020606113756/http://seattlepi.nwsource.com/transportation/54374_get14.shtml |archive-date=June 6, 2002 |accessdate=November 24, 2024}}</ref>

Due to damage from continuing settlement, a group of researchers and faculty from the University of Washington urged the mayor of Seattle (in 2007) to close the viaduct within a four-year timeframe.<ref>{{cite news |last1=Miles |first1=Scott |last2=Montgomery |first2=David R. |last3=Beyers |first3=Bill |date=March 2, 2006 |title=Shut down the viaduct |url=http://old.seattletimes.com/html/opinion/2002837776_viaduct02.html |work=The Seattle Times |access-date=July 21, 2016}}</ref>

===Tunnel planning and construction===
{{Main|Alaskan Way Viaduct replacement tunnel}}
[[File:Alaskan Way Demolition Oct 2011- 07.jpg|thumb|Demolition of the southernmost section of Alaskan Way Viaduct, October 2011]]
On January 12, 2009, the governments of Washington, [[King County, Washington|King County]], the city of [[Seattle]], and the [[Port of Seattle]] announced that they had agreed to replace the viaduct with a four-lane, {{convert|2|mi|km|adj=on}} long tunnel.<ref name="TunnelAnnounce">{{cite news |first=Andrew |last=Garber |title=Tunnel in place of viaduct: A deal, but how to pay? |url=http://seattletimes.com/html/localnews/2008621043_viaduct13m.html |work=The Seattle Times |date=January 13, 2009 |access-date=January 13, 2009}}</ref> The tunnel would have a south portal in [[SoDo, Seattle|SoDo]], near [[CenturyLink Field]], and a north portal near Thomas Street, north of the Battery Street Tunnel.<ref name="HAER2008"/>

The project was estimated to cost $4.25 billion, with state, city, and county promised funding well short of the estimate.<ref name="TunnelAnnounce" /> The state would fund boring of the tunnels, while the city and county would fund surface street improvements and repairs to the Alaskan Way Seawall, which itself was damaged in the Nisqually earthquake.<ref name="TunnelAnnounce" /> The announcement did little to quell the long and heated debate over the viaduct's replacement, with several factions expressing their criticism over the tunnel decision.<ref name="TunnelAnnounce" />

Boring of the tunnel by the [[tunnel boring machine]] "[[Bertha (tunnel boring machine)|Bertha]]" began on July 30, 2013, with the roadway initially scheduled to open in December 2015.<ref>{{cite news |last=Lindblom |first=Mike |date=July 30, 2013 |title=Bertha's excavation mission beginning under downtown |url=http://www.seattletimes.com/seattle-news/bertharsquos-excavation-mission-beginning-under-downtown/ |newspaper=[[The Seattle Times]] |access-date=July 21, 2016}}</ref> Tunneling stopped on December 6, 2013, after the boring machine struck a steel pipe, which obstructed its path {{convert|1,083|ft|m}} into the route. Investigations revealed that the machine had struck a pipe which had been installed in 2002 as a part of an exploratory well used to measure groundwater as part of the planning phases for the project. Boring resumed briefly on January 28–29, 2014, stopping again due to damage to the seal system which protects the machine's main bearing and damage to several of the cutting blades.<ref>{{cite news |date=February 7, 2014 |title=Feb. 7 update: Two factors contributed to tunnel stoppage |url=http://www.wsdot.wa.gov/Projects/Viaduct/Contents/Item/Display/1457 |publisher=Washington State Department of Transportation |access-date=July 21, 2016}}</ref> This caused a two-year delay as it was necessary to dig a {{convert|120|ft|m|adj=on}} vertical shaft recovery pit from the surface in order to access and lift the cutterhead for repair and partial replacement.<ref>{{cite news |last=Lindblom |first=Mike |date=January 30, 2015 |title=Bertha's repair pit reaches full depth of 120 feet |url=http://blogs.seattletimes.com/today/2015/01/berthas-repair-pit-reaches-full-depth-of-120-feet-depth/ |work=The Seattle Times |access-date=July 21, 2016}}</ref>

Work was initially expected to resume by March 2015,<ref>{{cite news |last=Cohen |first=Aubrey |date=April 21, 2014 |title=State: Bertha to get back to work by next March |url=http://www.seattlepi.com/local/transportation/article/State-Bertha-to-get-back-to-work-by-next-March-5418606.php |work=Seattle Post-Intelligencer |access-date=July 21, 2016}}</ref> but it was December 2015 before tunnelling recommenced.<ref>{{cite news |last=Lindblom |first=Mike |date=December 22, 2015 |title=Bertha back on the move after 2 years of delays |url=http://www.seattletimes.com/seattle-news/transportation/bertha-restarts-after-two-years-of-delays/ |work=The Seattle Times |access-date=July 21, 2016}}</ref> Boring was halted again 23 days later after a sinkhole developed on the ground in front of the machine,<ref>{{cite news |last=Lindblom |first=Mike |date=January 14, 2016 |title=Inslee orders tunnel dig halted as soil sinks above Bertha |url=http://www.seattletimes.com/seattle-news/transportation/inslee-orders-bertha-tunneling-stopped-after-sinkhole-forms/ |work=The Seattle Times |access-date=July 21, 2016}}</ref> but resumed a month later.<ref>{{cite news |last=Lindblom |first=Mike |date=February 23, 2016 |title=She's ba-ack! Yes, Bertha's on the move once again |url=http://www.seattletimes.com/seattle-news/transportation/shes-ba-ack-yes-berthas-on-the-move-once-again/ |newspaper=The Seattle Times |access-date=July 21, 2016}}</ref>

In July 2016, a citywide [[ballot measure]] attempted to build an [[elevated park]] along the waterfront after the demolition of the viaduct, utilizing a portion of the existing structure. The attempt failed, with more than 80 percent of voters in Seattle rejecting the measure.<ref>{{cite news |last=Madej |first=Patricia |date=August 2, 2016 |title=Voters soundly reject elevated waterfront park for downtown Seattle |url=http://www.seattletimes.com/seattle-news/politics/elevated-waterfront-park-initiative-results/ |work=The Seattle Times |access-date=August 3, 2016}}</ref> By this time, the tunnel was not expected to be completed until 2019, and had incurred $223 million in cost overruns.<ref>{{cite news |last=Lindblom |first=Mike |date=July 21, 2016 |title=Bertha's woes grind on: more delay, higher cost for Highway 99 tunnel |url=http://www.seattletimes.com/seattle-news/berthas-woes-grind-on-more-delay-higher-cost-for-highway-99-tunnel/ |newspaper=The Seattle Times |access-date=July 21, 2016}}</ref>

===Opening of new tunnel===

In March 2018, construction of the replacement tunnel was expected to be completed in August 2018, with a planned opening date of October 2018. Cost overruns had reached about $600 million due to the delays in tunnel boring.<ref>{{cite news |url=https://www.seattletimes.com/seattle-news/transportation/seattles-highway-99-tunnel-could-open-to-traffic-in-october/ |title=Seattle's Highway 99 tunnel could open to traffic in October |first=Mike |last=Lindblom |newspaper=[[The Seattle Times]] |date=March 27, 2018 |access-date=June 30, 2018}}</ref> WSDOT reverted to the tunnel's original opening date of early 2019 to accommodate a longer preparation period and avoid potential work delays due to winter weather. On January 11, 2019, the Alaskan Way Viaduct was permanently closed in preparation for the opening of the new tunnel, which required the excavation of several buried ramps at the south portal and other road realignments.<ref name="Lindblom"/>

The viaduct was opened to pedestrian traffic on February 2, 2019, and bicycle traffic the day after, as part of a festival to celebrate the freeway's history. Over 100,000 people attended the two events, which also included tours of the new tunnel.<ref>{{cite news |last=Gutman |first=David |date=February 2, 2019 |title='A huge achievement': Pedestrians swarm Seattle as viaduct comes down, tunnel set to open |url=https://www.seattletimes.com/seattle-news/transportation/tunnel-opening-goodbye-viaduct-festivities-feature-story/ |work=The Seattle Times |access-date=February 2, 2019}}</ref> The replacement tunnel was opened to traffic on February 4, 2019.<ref>{{cite news |last1=Lindblom |first1=Mike |last2=Baruchman |first2=Michelle |date=January 31, 2019 |title=Highway 99 tunnel opens next week. Here are answers to your questions about the project |url=https://www.seattletimes.com/seattle-news/transportation/the-highway-99-tunnel-opens-next-week-here-are-answers-to-your-questions-about-the-project/ |work=The Seattle Times |access-date=January 31, 2019}}</ref><ref>{{cite news |date=February 4, 2019 |title=SR 99 tunnel now open to traffic |url=http://www.wsdot.wa.gov/Projects/Viaduct/library/advisories-and-updates/sr-99-tunnel-now-open-to-traffic |publisher=Washington State Department of Transportation |access-date=February 4, 2019}}</ref>

===Demolition and replacement===
[[File:Alaskan Way Viaduct demolition at Columbia Street, April 2019 - 02.jpg|thumb|right|Demolition of the viaduct near Columbia Street, seen in early April 2019]]

Demolition of the viaduct began on February 15, 2019, after being delayed by several days due to a [[January–February 2019 North American cold wave#Washington|severe snowstorm]]. Contractors began with the upper deck and its columns, followed by the lower deck in a section-by-section process.<ref>{{cite news |last=Lindblom |first=Mike |date=April 22, 2019 |title=Tearing down the Alaskan Way Viaduct is taking longer than once thought |url=https://www.seattletimes.com/seattle-news/transportation/tearing-down-the-alaskan-way-viaduct-is-taking-longer-than-once-thought/ |work=The Seattle Times |access-date=May 13, 2019}}</ref> It was originally scheduled to be completed by June 2019, but a compressed schedule caused by the tunnel's delayed opening caused demolition to take longer than expected and conflict with the summer tourism season.<ref>{{cite news |last=Farley |first=Glenn |date=May 31, 2019 |title=Viaduct demolition delays thrill tourists, worry Seattle waterfront businesses |url=https://www.king5.com/article/news/local/seattle/viaduct-demolition-delays-thrill-tourists-worry-seattle-waterfront-businesses/281-1e118476-7ce0-4772-89c7-a19c18a8d5e5 |publisher=KING 5 |access-date=June 29, 2019}}</ref> Demolition work reached the 50 percent milestone on June 11, with the Pioneer Square and Pike Place Market sections left for the final stages.<ref>{{cite news |last=Janavel |first=AJ |date=June 11, 2019 |title=Viaduct demolition hits the halfway mark, officials say |url=https://q13fox.com/2019/06/11/viaduct-demolition-hits-the-halfway-mark-officials-say/ |publisher=Q13 Fox News |access-date=June 29, 2019}}</ref><ref>{{cite news |last=Lindblom |first=Mike |date=August 5, 2019 |title=Viaduct demolition reaches dramatic phase just feet from Pioneer Square buildings |url=https://www.seattletimes.com/seattle-news/transportation/viaduct-demolition-reaches-dramatic-phase-just-feet-from-pioneer-square-buildings/ |work=The Seattle Times |access-date=August 6, 2019}}</ref> The final double-deck section of the viaduct, including the Marion Street pedestrian bridge at [[Colman Dock]], was demolished in late September 2019. The final section of the viaduct, removed in November 2019, was over the northern portal of the [[Great Northern Tunnel]] near the Pike Place Market.<ref>{{cite news |last=Mutasa |first=Tammy |date=September 21, 2019 |title='End of an era': Viaduct's double decker section reduced to rubble |url=https://komonews.com/news/local/viaducts-double-decker-section-reduced-to-rubble-but-demolition-continues |publisher=KOMO 4 News |access-date=September 22, 2019}}</ref>

Demolition work was completed on November 21, 2019, with {{convert|240|e6lb|kg}} of concrete recycled and {{convert|15|e6lb|kg}} of steel rebar reclaimed.<ref>{{cite press release |date=November 21, 2019 |title=All done! Seattle's Alaskan Way Viaduct is history |url=https://www.wsdot.wa.gov/news/2019/11/21/all-done-alaskan-way-viaduct-history |publisher=Washington State Department of Transportation |access-date=November 21, 2019}}</ref> Some of the concrete from the demolition was pulverized and used to fill the [[Battery Street Tunnel]].<ref>{{cite news |last=Lindblom |first=Mike |date=February 14, 2019 |title=Crews will begin to crunch the Alaskan Way Viaduct into 3-inch chunks this week |url=https://www.seattletimes.com/seattle-news/transportation/the-long-goodbye-viaduct-ramp-demolition-begins-this-week-at-columbia-street/ |work=The Seattle Times |access-date=February 15, 2019}}</ref> New development along the waterfront in downtown Seattle, including a park promenade, was planned to be completed by 2021.{{update needed|date= September 2025}}<ref>{{cite news |last1=Lindblom |first1=Mike |title=Cost to demolish Alaskan Way Viaduct pegged at $93.7M |url=https://www.seattletimes.com/seattle-news/transportation/cost-to-demolish-alaskan-way-viaduct-pegged-at-93-7m/ |access-date=July 2, 2018 |work=The Seattle Times |date=May 16, 2018}}</ref><ref>{{cite web |title=Alaskan Way Viaduct - Demolition |url=http://www.wsdot.wa.gov/Projects/Viaduct/demolition |publisher=Washington State Department of Transportation |access-date=July 2, 2018}}</ref> The full program is scheduled to be completed in 2025 due to delays attributed to the [[COVID-19 pandemic]] and a concrete workers' strike.<ref>{{cite news |last=Zhou |first=Amanda |date=September 19, 2022 |title=Alaskan Way overnight closures begin for downtown waterfront project |url=https://www.seattletimes.com/seattle-news/alaskan-way-overnight-closures-begin-for-downtown-waterfront-project/ |work=The Seattle Times |accessdate=October 24, 2022}}</ref>

==Exit list==
The entire route was in [[Seattle]], [[King County, Washington|King County]]. All exits were unnumbered.
{{jctinttop|state=WA|nocty=yes}}
{{Jctint
|location_special=[[Industrial District, Seattle|Industrial District]]
|lspan=4
|mile=22.65
|mspan=2
|road={{jct|state=WA|SR|99|dir1=south|name1=Marginal Way}}
|notes=Continuation south
}}
{{Jctint
|mile=none
|type=incomplete
|road=Spokane Street – [[West Seattle, Seattle|West Seattle]]
|notes=Northbound exit and southbound entrance
}}
{{Jctint
|mile=22.74
|type=incomplete
|road=[[West Seattle Bridge]] – [[Harbor Island (Seattle)|Harbor Island]]
|notes=Southbound exit and northbound entrance
}}
{{Jctint
|mile=24.24
|type=incomplete
|road={{jct|state=WA|SR|519|name1=South Atlantic Street|dir1=south|I|90|I|5|to2=yes}}
|notes=Southbound exit and northbound entrance
}}
{{Jctint
|location_special=[[Pioneer Square, Seattle|Pioneer Square]]
|mile=25.03
|type=incomplete
|road=Columbia Street
|notes=Southbound entrance only
}}
{{Jctint
|location_special=[[Downtown Seattle|Downtown]]
|mile=25.04
|type=incomplete
|road=Seneca Street
|notes=Northbound exit only
}}
{{Jctint
|location_special=[[Belltown, Seattle|Belltown]]
|lspan=2
|mile=25.69
|mspan=2
|road=Western Avenue
}}
{{Jctint
|mile=none
|road={{jct|state=WA|SR|99|dir1=north|name1=[[Battery Street Tunnel]]}}
|notes=Continuation north
}}
{{jctbtm|keys=incomplete}}

==See also==
*[[California State Route 480|Embarcadero Freeway]], a former elevated freeway along the waterfront in San Francisco that was demolished.
*[[Central Artery|John F. Fitzgerald Expressway]], a former elevated freeway in Boston (Interstate 93) that was rerouted into a {{convert|3.5|mi|adj=on}} tunnel.
*[[List of tunnels documented by the Historic American Engineering Record in Washington (state)]]
*[[West Side Highway]], a former elevated freeway along the West Side waterfront in Manhattan that was partially replaced with an at-grade boulevard.

==References==
{{Reflist}}

==Bibliography==
*{{cite news |first=Susan |last=Gilmore |url=http://seattletimes.com/html/localnews/2003249507_webviaduct08.html |title=Two views of the viaduct |publisher=Seattle Times |date=September 8, 2006 |access-date=September 10, 2006 |format=article links to videos which require [[RealPlayer]] 10.5}}
*{{cite news |first=Susan |last=Gilmore |url=http://seattletimes.com/html/localnews/2003185081_viaduct09m.html |title=State offers 3 decidedly different designs for viaduct |publisher=Seattle Times |date=August 9, 2006 |access-date=August 15, 2006}}
*{{cite news |first=Susan |last=Gilmore |url=http://seattletimes.com/html/localnews/2003169038_viaduct02m.html |title=Idea of fixing viaduct seen as having merit but problems as well |publisher=Seattle Times |date=August 2, 2006 |access-date=August 2, 2006}}
*{{cite news |first=Susan |last=Gilmore |url=http://seattletimes.com/html/localnews/2003149875_viaduct25m.html |title=What will happen if viaduct closes? Study takes a look |publisher=Seattle Times |date=July 25, 2006 |access-date=July 25, 2006}}
*{{cite news |url=http://www.seattlepi.com/local/transportation/article/A-longer-shelf-life-for-the-viaduct-1202573.php |title=A Longer shelf life for the viaduct |publisher=Seattle P.I |date=May 3, 2006 |access-date=June 24, 2006 |first1=Larry |last1=Lange}}
*{{cite news |url=http://www.seattleweekly.com/news/0616/viaduct.php |title=Seattle's Little Dig |publisher=Seattle Weekly |date=April 19, 2006 |access-date=June 24, 2006 |archive-url=https://web.archive.org/web/20090814184318/http://www.seattleweekly.com/2006-04-19/news/seattle-s-little-dig/ |archive-date=August 14, 2009}}
*{{cite news |url=http://www.moreperfect.org/wiki/index.php?title=Alaskan_Way_Viaduct:_Transit_%26_Streets_Proposal:_Read_More |title=MorePerfect.org collected news stories |publisher=MorePerfect.org |url-status=dead |archive-url=https://web.archive.org/web/20090814210644/http://www.moreperfect.org/wiki/index.php?title=Alaskan_Way_Viaduct%3A_Transit_&_Streets_Proposal%3A_Read_More |archive-date=August 14, 2009}}
*"Viaduct Open to Cars Today." Viaduct Open to Cars Today [Seattle] April 5, 1953: n. pag. 1 Rpt. in The Seattle Post Intelligencer. Seattle: n.p., 1953.
*{{cite web |title=Alaska Way VIaduct and Battery Street Tunnel HAER WA-184 |url=http://viaducthistory.com/images/AWV_HAER_WA_184.pdf |publisher=Washington State Department of Transportation |access-date=March 26, 2014}}

==External links==
{{Attached KML|display=inline,title}}
{{Commons category}}
*[http://www.wsdot.wa.gov/projects/viaduct/ SR 99 – Alaskan Way Viaduct & Seawall Replacement Project]
*[[HistoryLink]] Alaskan Way Viaduct essays by  Jennifer Ott:
**[http://www.historylink.org/index.cfm?DisplayPage=output.cfm&file_id=9925 Alaskan Way Viaduct, Part 1: Early Transportation Planning] (September 13, 2011)
**[http://www.historylink.org/index.cfm?DisplayPage=output.cfm&file_id=9951 Alaskan Way Viaduct, Part 2: Planning and Design] (October 27, 2011)
**[http://www.historylink.org/index.cfm?DisplayPage=output.cfm&file_id=9978 Alaskan Way Viaduct, Part 3: Building the Viaduct] (December 3, 2011)
**[http://www.historylink.org/index.cfm?DisplayPage=output.cfm&file_id=9983 Alaskan Way Viaduct, Part 4: Replacing the Viaduct] (December 19, 2011)
**[http://www.historylink.org/index.cfm?DisplayPage=output.cfm&file_id=9977 Seattle's Columbia Street on-ramp to the Alaskan Way Viaduct opens to traffic on February 1, 1966] (December 26, 2011)
*{{HAER |survey=WA-184 |id=wa0830 |title=Alaskan Way Viaduct and Battery Street Tunnel, Seattle, King County, WA |photos=103 |data=35 |cap=10}}
*{{YouTube|id=zUvF0nDwTo4|title=Tearing down the Alaskan Way Viaduct and transforming Seattle's waterfront}}

{{Bridges of Seattle}}
{{Authority control}}

[[Category:Bridges in Seattle]]
[[Category:Roads in Washington (state)]]
[[Category:Bridges completed in 1953]]
[[Category:Historic American Engineering Record in Washington (state)]]
[[Category:U.S. Route 99]]
[[Category:Viaducts in the United States]]
[[Category:Road bridges in Washington (state)]]
[[Category:1953 establishments in Washington (state)]]
[[Category:2019 disestablishments in Washington (state)]]
[[Category:Buildings and structures demolished in 2019]]
[[Category:Concrete bridges in the United States]]
[[Category:Demolished bridges in the United States]]
[[Category:Demolished highways in the United States]]