Editing Alaskan Way Viaduct (section)

==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.<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>