Advisories and Updates 2015

2015 Program News

  • Dec. 23 project update: Bertha builds another ring

    Seattle Tunnel Partners built the SR 99 tunnel’s 160th concrete ring on Tuesday before securing the worksite for the holidays. Crews pushed the tunneling machine slowly forward in the access pit over the course of the day, testing its performance as they mined the 6.5 feet needed to install the next ring. A video of the ring-build is below.  
     
     
    In all, Bertha has excavated 8 feet of tunnel since STP restarted the machine early Tuesday. STP crews – which have been working long hours in the weeks leading up to the machine’s restart – will take a break over the holidays before resuming tunneling in the first week of January. 
     
    When work resumes, crews will mine through the concrete wall of the access pit and into the native soils that will serve as the next stage of STP’s testing process. This section of the tunnel route – like the 1,091 feet that came before it – is protected by underground walls that were built to hold the ground in place while crews continue to test the machine. 
     
    Bertha will mine toward an underground block of concrete approximately 450 feet north of the access pit. This area is the third and final protected maintenance stop, or safe haven, that STP built prior to the start of tunneling. According the STP’s most recent schedule, the machine will spend up to one month at the safe haven while crews perform maintenance and make final adjustments before tunneling beneath the Alaskan Way Viaduct.
     
    Safe haven 3
     
    WSDOT will fully close SR 99 through downtown for approximately two weeks while the machine passes beneath the viaduct. STP’s latest projections show that the closure will occur in March, but the actual closure date will depend on Bertha’s progress and the state cannot verify the contractor's schedule. Check our #99closure page as the closure approaches for additional details.
     
    Look for our next update in early 2016. Happy holidays from the Alaskan Way Viaduct Replacement Program.
     

     

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  • Construction Highlights for Friday, May 27 - Friday, June 3, 2016

    North End

     
    Tuesday, May 31 to Friday, June 3
    • Crews will close the right lane of southbound SR 99 at Raye, Comstock and Valley streets from 10 a.m. to 2 p.m.
     

     

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  • Dec. 22 project update: Bertha tunnels into next phase of testing

    The SR 99 tunneling machine entered its next phase of testing today near Pier 48, moving forward and installing a tunnel ring at the bottom of the 120-foot-deep pit crews built to access and repair the machine. Seattle Tunnel Partners plans to tunnel a short distance further in the access pit tunnel before giving crews a break for the holidays. 
     
    After the holidays, STP plans to mine out of the access pit toward a planned maintenance stop 450 feet to the north. Along the way crews will mine slowly while installing tunnel rings and continuing to run tests. When the machine reaches the maintenance stop – essentially an underground block of concrete just south of Colman Dock – crews will perform maintenance and make final adjustments before diving beneath the viaduct.
     
    Tunneling under the viaduct will require a full closure of SR 99 through downtown for approximately two weeks. The contractor’s latest projections show that the closure will occur in March, but the actual closure date will depend on Bertha’s progress and the state cannot verify the contractor's schedule. Details will be added to our newly launched #99closure page as the closure approaches.
     
    STP and Bertha’s manufacturer, Hitachi Zosen, are responsible for the repair effort, including the schedule. While the machine was under repair, STP continued essential work at the future tunnel portals, including construction of ramp and highway connections, and the buildings that will house tunnel operations.  
     
    STP crews halted tunneling in December 2013 after the machine overheated. After an investigation, they discovered damage to the seal system and determined it needed to be replaced along with the main bearing. The cause of the damage has not been determined. Responsibility for costs associated with the delay will be determined through the process outlined in the tunnel contract.
     
    Backfill time-lapse video
    Below is a new time-lapse video showing STP's work to backfill the access pit. Crews finished backfilling the pit over the weekend.
      
     
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  • Dec. 18 project update: Work continues at the access pit

    Seattle Tunnel Partners has spent much of the week backfilling the SR 99 tunnel access pit. By Friday, only part of the machine’s shield and cutterhead were visible from our time-lapse camera. Crews stopped backfilling on Wednesday afternoon to repair a mixing arm that broke off inside the machine during testing of the cutterhead. Backfilling has since resumed and will continue over the weekend.
     
    STP has indicated they may fill the remainder of the pit with a concrete-sand mixture in addition to material removed during excavation. Using the concrete-sand mixture – rather than sand and soil, as STP previously planned – could reduce the time it will take to complete backfilling. Additionally, the deep dewatering wells that have been used to control groundwater in the pit may be turned off sometime in January. STP previously planned to turn them off this month.
     
    STP has told us they plan to move the SR 99 tunneling machine forward by Dec. 23, the date shown in their most recent schedule. As part of their testing program, STP intends to tunnel forward a short distance in the pit before taking a break for the holidays. After the holidays, STP plans to mine out of the access pit toward a planned maintenance stop approximately 450 feet to the north. Along the way crews will mine forward and install tunnel rings while continuing to run tests.
     
    The state cannot verify the contractor's schedule, but we will continue to provide updates as STP's work progresses.
     
    To learn more about STP's repair effort, watch this narrated video (links to YouTube).
     
    STP backfills the access pit
    Crews backfill the SR 99 tunnel access pit on Tuesday.
     
    Previous Updates
     
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  • Dec. 14 project update: Seattle Tunnel Partners begins backfilling the access pit

    Seattle Tunnel Partners continues to prepare the SR 99 tunneling machine for mining. Crews have spent several weeks conducting a series of preliminary tests – including rotation of the cutterhead in the open air at the bottom of the 120-foot-deep pit that was built to access and repair the machine. Over the weekend, STP began filling in the access pit with sand and soil – the final step before they resume mining.

    The following graphics illustrate this phase of STP’s repair effort.

    Current conditions

    Bertha currently sits on a concrete cradle at the bottom of the access pit, approximately 20 feet from the wall she will tunnel through when mining resumes.

    Step 1

    STP has placed gravel under and beside the machine to fill the gap between the machine and cradle.

    Step 2

    Next, STP added a low strength concrete-sand mixture to the portion of the cradle in front of the machine to assure good contact between the rings and the cradle. This provides a firm surface for the machine to mine through.

    Step 3

    On Sunday, STP began filling the pit with sand, which will rise up to 4 feet above the top of the tunneling machine. The excavation chamber behind the cutterhead will also be filled with sand. Sand flows better than other soils and quickly allows water to move through it, which will help crews achieve the required density. 

    Step 4

    The remaining 51 feet to the ground surface will be filled with compacted soil originally excavated from the access pit. Once the pit has been backfilled, STP will commence final testing and prepare to resume mining.

    Controlling groundwater

    During the backfilling process, STP will incrementally turn off the dewatering wells that crews have been using to control groundwater. We will continue to monitor movement of the ground, structures, utilities and the viaduct. Additional information about our ground monitoring program can be found here

    STP's most recent schedule shows the machine will be ready to resume mining in the pit on Dec. 23. The state cannot verify the contractor's schedule.

     

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  • The part of the SR 99 tunnel built without Bertha

    Bertha is one part of the construction story of the State Route 99 tunnel. The other part of the story is the approximately 20 percent of the tunnel designed to be built without a tunneling machine. Seattle Tunnel Partners bored more than 1,000 feet of tunnel before they stopped to repair Bertha. While the repairs were ongoing, an additional 1,200 feet of cut-and-cover tunnel was built by the contractor. It’s still all the SR 99 tunnel  just different methods of construction.
     
    Using cut-and-cover construction at both ends of the bored tunnel gives Seattle Tunnel Partners the best way to gradually connect the northbound and southbound lanes of SR 99  which run side-by-side on the surface – to Bertha’s piece of the tunnel, where the roadway becomes a double-decker.
     
    Most of the cut-and-cover construction has taken place underground, out of sight of the public. This video gives a close-up look inside the newest part of the project to learn more about the part of the SR 99 tunnel built without Bertha.
     
     
    Approximate tunnel length:
    • Bored and cut-and-cover tunnel combined: 11,000 feet 
    • Bored tunnel: 9,300 feet (1,000 feet bored to date)
    • Cut-and-cover tunnel: 1,700 feet (1,200 feet built to date)
     
    The video below illustrates how a cut-and-cover tunnel is built.
     
     
     

     

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  • Nov. 24 project update: Video of Seattle Tunnel Partners rotating Bertha's cutterhead

    Commissioning of the SR 99 tunneling machine continues as Seattle Tunnel Partners prepares to resume mining. STP began testing machine components earlier this month as crews continued welding pieces and reconnecting hoses and cables. Last week, STP began rotating the machine’s cutterhead a few degrees at a time, stopping periodically to take measurements before completing a full rotation.
     
    Tuesday, Nov. 24 marked the first sustained rotation of the cutterhead since the machine broke through the southern wall (links to YouTube) of the access pit on Feb. 19. STP indicated they will rotate the cutterhead in both directions for about one hour at a time. Watch a short video of the cutterhead rotating below.
     
     
    During the next phase of commissioning, STP will backfill the access pit with sand and gravel to prepare the machine for mining. STP's most recent schedule shows that the machine will be ready to resume mining on Dec. 23. The state cannot verify the contractor's schedule.
     
    Previous updates
     

    Nov. 12 project update: Tunneling machine testing underway

    For earlier program updates, please visit our archive page
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  • Nov. 12 project update: Tunneling machine testing underway

    Seattle Tunnel Partners and manufacturer Hitachi Zosen have begun testing components of the SR 99 tunneling machine as they prepare to resume mining. A few initial tests were performed last week, and several others are slated to occur in the coming weeks.
     
    This week’s highlights include tests of various pumps inside the machine, as well as the screw conveyor system that carries excavated material from the cutterhead to the back of the machine and out of the tunnel. All of the tests are being conducted by STP and Hitachi Zosen, who are jointly responsible for ensuring the machine is ready to complete the remainder of the tunnel drive. Future tests will include rotation of the machine’s cutterhead, which, according to STP, will occur in late November.
     
    Some reassembly work is ongoing. Major components of the machine are in place, but crews continue to weld pieces together and reconnect wires and hoses. STP’s most recent schedule shows that the machine will be ready to resume mining on Dec. 23. WSDOT cannot verify the contractor’s schedule. The narrated video below explains STP’s repair effort in more detail.
     
     
    Other work
    STP crews have finished treating the ground north of the access pit. They began injecting grout into the soil there last month to stabilize the area where the machine will exit the access pit. Crews will soon place a thin layer of sand at the bottom of the pit; the rest of the pit will be filled after initial testing is complete. 
     
    STP crews are also preparing to install glass walls at the operations buildings located at each portal. The north building’s glass will be installed first. Read more about those efforts in this post.
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  • Oct. 22 project update: Seattle Tunnel Partners schedule update now online

    Each month, Seattle Tunnel Partners submits an updated construction schedule to WSDOT. These schedules show STP’s latest projection for completing the project, in addition to listing a number of important construction activities they must complete along the way.
     
    STP’s latest schedule (pdf 291 kb), which was posted Thursday afternoon, shows that mining will resume on Dec. 23, 2015 – one month later than the date shown in the previous schedule. Accordingly, the tunnel opening date in the new schedule also has moved by one month, to April 2018. STP has told us the changes in the schedule reflect the current emphasis on giving crews the time they need to complete the tunneling machine repairs successfully.
     
    Like all large construction projects, the schedule for this project changes frequently. WSDOT cannot verify any of the dates shown in this schedule.
     
    Work continues
     
    As this Oct. 14 post explains, STP has begun treating the ground north of the access pit through a process known as jet grouting. This work will stabilize the ground above the tunnel as the machine exits the pit. 
     
    Additionally, STP and manufacturer Hitachi Zosen are continuing to reconnect machine parts in preparation for mining. That work includes welding pieces together, and reconnecting hoses and wires. STP Project Manager Chris Dixon outlines the steps STP is taking to resume tunneling in this video (links to YouTube). 
     
    You can track STP’s repair effort on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates. We’ll also continue to post photos and videos as work progresses.
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  • Oct. 14 project update: Preparing Bertha’s future path

    This week, Seattle Tunnel Partners will begin treating the ground just north of the access pit. This work – known as jet grouting – will inject a mixture of cement and water into the soil, which will stabilize the ground above the tunnel as the machine exits the access pit. 
     
    STP started setting up equipment for this work earlier this week. When the operation begins, crews will use a high-pressure pump to inject grout into the ground adjacent to the access pit’s north wall, creating a set of interlocking columns approximately five feet in diameter. The top of the columns will begin approximately 20 feet below the surface, and will extend down approximately 40 feet, stopping just above the tunnel route. STP expects this work to take approximately six weeks.
     
    Meanwhile, STP and manufacturer Hitachi Zosen are continuing to reconnect machine parts in preparation for mining. That work includes welding pieces together, and reconnecting hoses and wires. STP Project Manager Chris Dixon outlines the steps STP is taking to resume tunneling in this video (links to YouTube). 
     
    You can track STP’s repair effort on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates. We’ll also continue to post photos and videos as work progresses. 
     
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  • Statement from WSDOT regarding the SR 99 Tunnel Project

    “WSDOT is committed to working with Seattle Tunnel Partners to complete the SR 99 Tunnel Project. 
     
    We are also committed to protecting taxpayers. 
     
    Today, WSDOT filed a lawsuit against STP in King County Superior Court. This filing was prompted by recent court filings by STP and their insurance companies. Filing this lawsuit ensures WSDOT will have a right to make legal claims in the future. This lawsuit does not prevent STP from pursuing claims under the terms of the design-build contract.
     
    Taking action to preserve WSDOT’s rights in court was a necessary step. Our focus remains on completing the project, and removing the seismically vulnerable Alaskan Way Viaduct. We intend to ask for a stay of WSDOT’s lawsuit until the project is completed and asked STP to join us in this request. 
     
    This delay in the lawsuit will allow for work on the SR 99 Tunnel Project to be completed before litigation takes place.  
     
    The intent of today’s action is simple: protect the interests of Washington taxpayers. 
     
    There will be no further statements on this legal matter.”
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  • Oct. 7 project update: New video shows Bertha repair effort

    Work continues at the bottom of the 120-foot-deep pit where Seattle Tunnel Partners is readying Bertha, the SR 99 tunneling machine, for the rest of her tunnel drive beneath downtown Seattle. With repairs at the surface complete and all major components of the tunneling machine safely in the pit, STP and manufacturer Hitachi Zosen are focused on completing the reassembly portion of their repair effort.
     
    Crews are currently welding pieces of the machine back together, and reconnecting hundreds of wires and hoses that are integral to the tunneling operation. Although significant work is ongoing, much of it is can’t be seen from the surface. As part of our ongoing effort to keep the public informed about STP’s work, we asked STP Project Manager Chris Dixon to recap their repair effort to date and explain what’s next as they work to get Bertha moving again. Check out the resulting video, which includes exclusive shots of work occurring inside the machine and the access pit.
     
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  • Viaduct to close Halloween weekend for its semiannual inspection

    October is here, which means the semiannual inspection closure of the Alaskan Way Viaduct is just around the corner.
     
    Both directions of SR 99 will be closed between South Spokane Street and the north end of the Battery Street Tunnel from 6 a.m. to 6 p.m. on both Saturday, Oct. 31 and Sunday, Nov. 1. Please plan ahead and be prepared for additional congestion as a result of this closure.
     
    Closing the viaduct will allow crews to perform maintenance and thoroughly inspect the structure, as they do each spring and fall. Read our viaduct safety fact sheet (pdf 2.9 Mb) to learn more about what we do to keep the viaduct safe and open to drivers until the tunnel project is complete.  
     
    Viaduct inspection
    Survey crews walk the viaduct during a previous inspection.
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  • Milepost 31 Speaker Series: How changing transportation technologies have shaped Seattle’s waterfront

    The SR 99 tunnel will pass through a landscape that has been radically transformed. Go back 160-odd years and high tide laps at the foot of the bluff below Pike Place Market and tide flats reach all the way to the base of Beacon Hill. Join us at 6 p.m. on Thursday, Oct. 1 at Milepost 31, as historian Jennifer Ott discusses how changing transportation technologies – from canoes to container ships – have helped shape Seattle’s waterfront.
     
    Ott is an environmental historian with a particular interest in Seattle's history of moving dirt, rerouting waterways and leveling hills. She is a staff historian for HistoryLink.org and has written for Seattle Magazine and the Oregon Historical Quarterly.
     
    Viaduct construction
    Alaskan Way Viaduct construction, circa 1952.
     
    About our Milepost 31 speaker series

    We host a monthly speaker series at Milepost 31 to give visitors more insight into our work to replace the viaduct and the history of the Pioneer Square neighborhood. The event is held in conjunction with Pioneer Square's First Thursday Art Walk

    6 - 6:30 p.m.
    Thursday, Oct. 1
    Milepost 31211 First Ave. S., Seattle
    Admission is free

    After the talk, be sure to leave enough time to explore the rest of the First Thursday Art Walk in Pioneer Square. Milepost 31 is open Tuesdays through Saturdays from 11 a.m. to 5 p.m., and stays open until 8 p.m. on First Thursdays. Free parking is available for First Thursday art walk patrons in Pioneer Square. Please visit www.FirstThursdaySeattle.com for more information about participating garages.
     
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  • Sept. 8 project update: Final three pieces of tunneling machine safely in the access pit

    Seattle Tunnel Partners has successfully lowered three large pieces of the SR 99 tunneling machine’s front shield into the access pit for reassembly. On Saturday, Aug. 29 and Monday, Aug. 31, respectively, crane crews from Mammoet lowered two 98-ton side body pieces:

    Side body piece being lowered into the access pit

    On Friday, Sept. 4, the 278-ton middle shield was lowered. Our construction cameras will show you a photo sequence of Friday's lift and lowering. Here's a capture from the camera:

    top shield being lowered

    With all major components of the machine now in the pit, crews are focusing on reassembling the machine and preparing for the testing phase of the repair effort. Crews will spend the coming weeks welding pieces back together, in addition to the lengthy task of reconnecting the hundreds of wires and hoses that are integral to the tunneling operation. STP and manufacturer Hitachi Zosen will conduct a series of tests following reassembly to ensure the machine is ready to resume mining.

    You can continue to track STP’s repair effort on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates.

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  • Aug. 27 project update: Tunneling machine’s front end bolted in place

    Seattle Tunnel Partners has reconnected the SR 99 tunneling machine’s 2,000-ton front end to the section that remained in the access pit during repairs. With the two sections of the machine now bolted together, crews from Mammoet have unhooked the front-end piece from the massive red crane that performed this week’s lift.
     
    Photos of the lift are available on Flickr, and the time-lapse video below shows the whole thing in 62 seconds.
     
     

    What's next?

    Significant work remains for crews tasked with reassembling the machine. Three large pieces of the machine’s outer shield will be lowered into place for reassembly in the coming days, according to STP’s most recent schedule. Crews also must weld the pieces back together, in addition to the lengthy task of reconnecting the hundreds of wires and hoses that are integral to the tunneling operation. STP and manufacturer Hitachi Zosen will conduct a series of tests following reassembly to ensure the machine is ready to resume mining.
     
    You can track the action on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates. We’ll also continue to post photos and videos as STP’s work progresses. 
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  • Aug. 25 project update: Seattle Tunnel Partners successfully lowers tunneling machine's front end into the access pit

    3:20 p.m. update: Seattle Tunnel Partners and crane crews from Mammoet have successfully lowered the 2,000-ton front end of the SR 99 tunneling machine to a platform at the bottom of the access pit.
     
    Crews will now use the crane to fine-tune the position of the piece. When that process is complete, they will begin reconnecting the piece to the portion of the machine that remains in the ground.
     
    The effort to return the tunneling machine's front end to the 120-foot-deep access pit began early Monday morning. Crews started by vertically lifting the piece, which includes the machine’s cutterhead, motors and the new main bearing assembly. The crane then moved horizontally on its rails to the north. When the piece was above the pit, crews rotated it to a semi-vertical position and lowered it partway into the pit before breaking for the evening. Work resumed early Tuesday morning, with the piece reaching the bottom of the pit Tuesday afternoon.
     
    Three pieces of the machine’s shield that remain at the surface will be lowered and reinstalled in the coming days, according to STP’s latest schedule. After the machine has been reassembled, STP and manufacturer Hitachi Zosen will conduct a series of tests will follow reassembly to ensure the machine is ready to resume mining.
     
    Lowering into pit
    The tunneling machine's front end as it nears the bottom of the pit on Tuesday afternoon.
     
    ***
     
    Original post: On Tuesday morning, Seattle Tunnel Partners and crane crews from Mammoet resumed lowering the front end of the tunneling machine into the access pit. 
     
    The effort to return Bertha to the 120-foot-deep access pit began early Monday morning. Crews started by vertically lifting the piece, which includes the machine’s cutterhead, motors and the new main bearing assembly. The crane then moved horizontally on its rails to the north. When the piece was above the pit, crews rotated it to a semi-vertical position and then lowered it partway into the pit before breaking for the evening.
     
    We’ll continue to provide updates here and on Twitter as the work progresses. 
     
    View from the crane
    The view from the top of the crane responsible for lowering machine parts back into the access pit.
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  • Aug. 24 project update: Seattle Tunnel Partners planning to lower Bertha into the access pit today

    5:30 p.m. update: The front end of the tunneling machine has been partially lowered into the access pit. Crane crews will break for the evening and lower the piece to the bottom of the pit on Tuesday. Look for an update in the morning. 
     
    12:34 p.m. update: With the front end of the tunneling machine now suspended above the access pit, crews have begun rotating it vertically. When the piece is in position, crews will begin lowering it toward the bottom of the pit. Track the action on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates.
     
    Cutterhead lift
    A shot of the machine's front end suspended over the access pit.
     
    11:14 a.m. update: The front end of the tunneling machine has been safely lifted off the ground. Crews have begun moving the crane horizontally toward the access pit. You can track the action on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates.
     
    ***
     
    After completing motor installation over the weekend, Seattle Tunnel Partners is nearly ready to lower the SR 99 tunneling machine’s newly reassembled front end into the access pit. 
     
    Crane crews have finished connecting the 2,000-ton piece to the crane and are performing final tests. They expect to begin the lift later this morning. Lifting and lowering the piece into the 120-foot-deep pit could take 14 hours or more, but there is no set schedule. Crews will take as long as necessary to prepare for and safely complete their work.
     
    The front-end section is the largest of four pieces that will be lowered into the pit for reassembly in coming days. The section being lifted today includes the machine’s cutterhead, motors and the new main bearing assembly.
     
    The crane doing the lifting was built by Mammoet, a firm that has performed similar lifts around the world, including the successful recovery of a Russian nuclear submarine from the bottom of the Barents Sea. Equipped with nearly seven miles of steel cable, the crane lowering Bertha into the pit is capable of lifting more than 2,400 tons. This video (links to YouTube) shows what it looked like when Mammoet lifted this section of the machine from the pit on March 30. This narrated video (links to YouTube) explains the entire repair sequence in detail.
     
    Once the front end of the machine is in place at the bottom of the pit, crews will begin reconnecting wires, hoses and cables to the portion of the machine that remains in the ground. STP’s latest schedule shows that three pieces of the machine’s outer shield will be lowered into the pit for reassembly in the days following the front-end lift. A series of tests will follow reassembly to ensure the machine is ready to resume mining.
     
    We’ll continue to update this post as the lift progresses. You can also track the action on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates.
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  • Aug. 21 project update: Motor installation nearly complete

    Seattle Tunnel Partners has nearly completed installation of the SR 99 tunneling machine’s motors. When the last motor has been installed, crane crews from Mammoet will make final preparations for lowering the machine’s newly reassembled front end into the access pit. 
     
    The more than 2,000-ton lift could occur as soon as next week. Lifting and lowering the massive piece could take 14 hours or more, but there is no set schedule. Crews will take as long as necessary to prepare for and safely complete their work.
     
    Once the piece is in place at the bottom of the pit, crews will begin reconnecting wires, hoses and cables to the portion of the machine that remains in the ground. STP’s latest schedule shows that three pieces of the machine’s outer shield will be lowered into the pit for reassembly in the days following the front-end lift. A series of tests will follow reassembly to ensure the machine is ready to resume mining.
     
    You can track the action on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates. We’ll also continue to post photos and videos as STP’s work progresses. 
     
    Motor installation
     
    Crews install motors in the SR 99 tunneling machine earlier this week.
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  • SR 99/Aurora Avenue North closed this weekend near South Lake Union

    Crews working for the Washington State Department of Transportation will close State Route 99/Aurora Avenue North near South Lake Union from Friday night, Aug. 21 through Monday morning, Aug. 24. Travelers should plan ahead and prepare for additional congestion on nearby streets during this time. We urge you to “know before you go” and use WSDOT’s travel tools or SDOT’s traveler’s information web page. Scroll down for complete closure details.  

    During the closure, crews will move the northbound and southbound lanes of SR 99 near Harrison Street onto a new structure to the west of the existing highway. Shifting traffic to these new lanes will provide space for ongoing construction of the SR 99 tunnel’s future north portal. SR 99 will remain two lanes in each direction in this area.  

    Map of traffic shift
    Click map to enlarge
     
    Shifting traffic to this new section of SR 99 is an important milestone for the SR 99 Tunnel Project. Check out our video for a better understanding of what the future will look like at the tunnel’s north portal. 
     
     

     
    SR 99 closure details
     
    SR 99/Aurora Avenue North closed between the south end of the Battery Street Tunnel and Valley Street 
    • Southbound lanes closed from 10 p.m. Friday, Aug. 21 to 5 a.m. Monday, Aug. 24.
    • Northbound lanes closed Friday, Aug. 21 staring two hours after the Mariners game to help fans get home from the game. All lanes will reopen by 5 a.m. Monday, Aug. 24. 

     

    Aurora Bridge

    • WSDOT crews will close up to two lanes of northbound SR 99 across the Aurora Bridge for bridge maintenance work from 5 a.m. to 5 p.m. Saturday, Aug. 22. Up to two lanes of southbound SR 99 across the bridge will be closed from 5 a.m. to 5 p.m. Sunday, Aug. 23.

     

    Changes to Harrison Street at SR 99 starting Aug. 24
    • Drivers will no longer be able to enter northbound SR 99 via westbound Harrison Street. This closure will allow crews to complete additional work over the next several months. Access to northbound SR 99 from Thomas and John streets will remain open.  
    • Northbound drivers on SR 99 will be able to exit at Harrison Street as they do today.
     
    Questions?
    Please contact us at viaduct@wsdot.wa.gov or 1-888-AWV-LINE (298-5463). 
     
    Originally posted July 28
     
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  • Aug. 17 project update: Reconnecting Bertha’s front end

    Seattle Tunnel Partners has begun reconnecting the two largest pieces of the SR 99 tunneling machine’s front end. On Saturday, Aug. 15, crane crews from Mammoet lifted the machine’s bearing block into place atop the cutterhead and drive unit. The newly reconnected front end of the machine will remain at the surface while Hitachi Zosen installs its motors. When installation of the motors is complete, Mammoet will lower the 2,000-ton piece back into the pit. This narrated video (links to YouTube) explains the repair sequence in detail.

    STP’s most recent schedule indicated the lowering of pieces would begin in early August, but some parts had to be remanufactured due to tight tolerances – measured in millimeters – that need to be met as the machine is reassembled. Those new parts have since arrived and been successfully installed. STP has a plan in place to resume tunneling in late November as scheduled. The state cannot verify the contractor’s schedule.

    Once the machine is in the pit, crews will begin the lengthy task of reconnecting wires, hoses and other parts to the portion of the machine that remains in the ground. A series of tests will follow to ensure the machine is ready to resume mining.

    We will continue to provide updates as STP’s repair effort continues. You can also track their progress by watching our construction cameras and following Bertha on Twitter @BerthaDigsSR99.

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  • Aug. 6 project update: Preparing to put Bertha back in the access pit

    Seattle Tunnel Partners has begun preparing for their next big milestone: Lowering the repaired front end of the SR 99 tunneling machine back into the access pit.

    Much of the repair and reassembly work is now complete. STP is awaiting the arrival of rollers and cages, parts of the machine’s new main bearing. STP chose to remanufacture some parts because of tight tolerances – measured in millimeters – that need to be met as the machine is reassembled. STP indicated the lowering of pieces into the pit will now occur two weeks later than the date shown on STP’s most recent schedule. STP has a plan in place to resume tunneling in late November as scheduled. The contractor’s monthly schedules are posted online.

    Rollers

    Radial rollers and their cages (circled in orange) – among the parts of the machine's main bearing currently being replaced.

    Crews from Mammoet, the firm that built and operates the Modular Lift Tower, will begin running tests of the crane as soon as next week. Once the MLT and the machine are ready, Mammoet will use the crane to reassemble the machine’s front end at the surface. This will set the stage for the big lift into the pit, which will be similar to the retrieval lift that occurred in March

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  • Northbound viaduct closure scheduled for Saturday evening

    The Seafair Pirate Run will close the northbound lanes of the Alaskan Way Viaduct Saturday evening from 6:30 p.m. to 9 p.m. The closure will extend from South Royal Brougham Way to the south end of the Battery Street Tunnel.
     
    The viaduct closure is part of a number of road closures associated with Seafair events on Saturday, so be sure to plan ahead if you’re headed to or through downtown Seattle.
     
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    Order: 4

  • July 22 project update: Yellow stacks installed at the north portal

    Earlier this month, the work zone to the west of Seattle’s stadiums got a bit brighter when Seattle Tunnel Partners installed four yellow ventilation stacks at the south operations building. This week it’s the north portal’s turn, as STP installs the north operations building’s ventilation stacks.
     
    The four yellow stacks were lifted into place Wednesday at the north portal site, which is located just east of the Gates Foundation. Manufactured in Longview, Wash. with American-made steel, the stacks will be part of the tunnel’s ventilation system. This post from April explains a bit more about the function of the two operations buildings.
     
    The color of the stacks was inspired by WSDOT’s yellow maintenance vehicles, some of which will be stored within the operations buildings. Like all aspects of the design, the color was developed with guidance from the Seattle Design Commission. 
     
    Image of north portal ventilation stacks
     
    Four tunnel ventilation stacks were installed Wednesday at the the tunnel's north portal, near the Space Needle.
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  • July 17 project update: Seattle Tunnel Partners submits new schedule for completing SR 99 Tunnel Project

    This week, Seattle Tunnel Partners began installing a new main bearing on the SR 99 tunneling machine. Installation of the machine’s most critical part comes on the heels of another vital piece of STP’s repair effort: an updated schedule that outlines the path for the machine’s launch beneath downtown and completion of the tunnel project.
     
    The SR 99 tunnel is now scheduled to open to drivers in spring 2018, according to a revised schedule (pdf 156 kb) STP submitted to the Washington State Department of Transportation. Machine repairs are scheduled to wrap up this fall. STP and manufacturer Hitachi Zosen will then perform an extended series of tests to ensure the machine is ready to complete the tunnel drive. 
     
    Tunneling is slated to resume in late November, with the machine emerging at the north end of downtown approximately one year later. The state is not able to verify the contractor’s schedule. 
     
    “The contractor’s schedule has changed, but the contract that governs their work remains the same,” said Todd Trepanier, WSDOT’s Alaskan Way Viaduct Replacement Program administrator. “The state is a paying customer in this transaction, and we’re intent on getting what we contracted for. We will continue to protect taxpayers and hold the contractor responsible for their work as they deliver this vital project.”
     
    Since lifting the front end of the machine from the ground in March, STP has fully assessed the disassembled machine parts and made significant repairs and enhancements (pdf 6.2 Mb). In addition to beginning installation of the main bearing, STP crews have installed portions of the new seal system that will protect the bearing. Modifications include the addition of reinforcing steel, new monitoring systems and upgrades to the soil-conditioning system to prevent clogging.  
     
    “Fully disassembling and assessing the machine was always the key to determining how long the repairs would take,” said Chris Dixon, Seattle Tunnel Partners project manager. “We want to reassemble the machine and resume tunneling as quickly as possible, but we also want to ensure the repairs are done right.”
     
    STP and Hitachi are responsible for the repair effort, including the schedule. While the machine has been under repair, STP has continued essential work at the future tunnel portals, including construction of ramp and highway connections, and the buildings that will house tunnel operations.  
     
    STP crews halted tunneling in December 2013 after the machine overheated. After an investigation, they discovered damage to the seal system and determined it needed to be replaced along with the main bearing. The cause of the damage has not been determined. Responsibility for costs associated with the delay will be determined through the process outlined in the tunnel contract.   
     
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  • Visit our information booths in West Seattle and Ballard this weekend

    Got a question about the viaduct program or want more information? We’ll be staffing a booth at the West Seattle Summer Fest and Ballard Seafoodfest this weekend. 
     
    West Seattle Summer Fest | Friday – Sunday, July 10-12
    Ballard SeafoodFest | Saturday – Sunday, July 11-12
     
    We’ll also be at two more Seattle events in the next 30 days:
     
    Phinney Farmers Market | Friday, July 24
    South Lake Union Block Party | Friday, August 7
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  • July 7 project update: A splash of color for the south portal

    This week, the muted tones of the south portal construction area will welcome an accent of yellow. The infusion of color will come courtesy of four 40-foot-tall, brightly painted steel ventilation stacks that are to be installed at the south portal operations building.
     
    The stacks are central to the tunnel’s ventilation system, which will be capable of removing 1.4 million cubic feet of air per minute should it be necessary. The operations buildings at each end of the tunnel will house operating systems, including safety, lighting and communications. Additionally, they’ll provide space and access for the very thing that inspired the colorful stacks – WSDOT’s yellow maintenance vehicles. Like all aspects of the design, the color palette was developed with guidance from the Seattle Design Commission.
     
    SR 99 tunnel south operations building image
     
    WSDOT and Seattle Tunnel Partners worked with the Seattle Design Commission on the final look and color scheme of the tunnel operations buildings.
     
    Manufactured in Longview, Wash. with American-made steel, the stacks will be delivered by truck to the work zone over the next few days. Crane crews will then hoist them into place before bolting them to the building’s steel frame. If the stacks had their own baseball card, here are some facts that might appear on the back:
     
    • Height above street level: 102 feet
    • Weight: Approximately 30,000 pounds of steel
    • Diameter: 10 feet
    • Thickness: Three-eighths of an inch
    • Professional debut: July 7 to 8, 2015
    • Position: Vertical
    • Birthplace: The stacks were manufactured in Longview, Wash. by Wayron, a DBE firm based there.
     
    The north portal operations building will also have four yellow ventilation stacks, but their delivery date has yet to be determined. Both buildings were the subject of this post back in April. Crews have made substantial progress on the structures since then, with the ventilation stacks being the most visible markers of that progress to date.
     
    SR 99 tunnel ventilation stack installation
     
    Seattle Tunnel Partners began installing ventilation stacks at the south operations building on July 7.

     

    A one-minute look at the installation of the SR 99 tunnel’s bright yellow ventilation stacks.

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  • Summer is the season for Milepost 31

    Hoping to catch a glimpse of SR 99 tunnel construction? Summer is an ideal time to visit Milepost 31, our project information center, located at 211 First Ave. S. in Seattle’s Pioneer Square neighborhood. Our free public tours give visitors a great view of the work site from a section of the Alaskan Way Viaduct that has been permanently closed to traffic. 

    Tours depart from Milepost 31 Tuesday through Saturday. Advance registration is required. Each tour is a half-mile round trip, and visitors must be able to walk over uneven ground and climb up and down 50 stairs.

    After the tour, stick around to look at the exhibits about the people and projects that shaped Pioneer Square. Learn how natural forces and people transformed Seattle’s landscape over time, and get an inside look at the SR 99 Tunnel Project.

    No speaker series in July

    Normally we host a monthly speaker series in conjunction with Pioneer Square’s First Thursday Art Walk, but due to the holiday we won’t be hosting the event in July. Milepost 31 will remain open until 8 p.m. on July 2 for the Art Walk. The center will be closed on July 3 and 4. Speaker Series will resume on Aug. 6.

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  • June 5 project update: Installation of new seal system underway

    Seattle Tunnel Partners has begun installing the SR 99 tunneling machine’s newly redesigned seal system. Crews lowered the new outer seal ring into place Wednesday, marking the first new piece to be installed in the machine as part of STP’s effort to resume tunneling.
     
    The new outer seal system arrived in October and was stored on-site prior to Wednesday’s installation. The new inner seal system arrived last week and is currently being installed. Made in Japan by manufacturer Hitachi Zosen, the new seal system will be easier to access should the need arise.
     
     
    Crews look on as the tunneling machine’s new outer seal ring is moved and placed on the cutterhead.
     
    We will continue to provide updates as we receive them.
     
    Digging into STP’s repair plan
    You can continue to track STP’s work on our time-lapse cameras and follow @BerthaDigsSR99 on Twitter for updates. Don't forget to check out the other resources we've created to give you a fuller understanding of Bertha's story:

     

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  • May 29 project update: New parts for Bertha arrive at Terminal 46

    The SR 99 tunneling machine’s new inner seals arrived from Japan as scheduled this week. The pieces, which are integral to Seattle Tunnel Partners’ effort to repair the machine, were offloaded at Terminal 46 and trucked a short distance north to the repair area. The piece shown below is the new inner seal ring, which houses the rubber seals that will protect the new main bearing. Additional photos of crews transporting the piece are available on Flickr.

    The SR 99 tunneling machine's inner seal ring

    STP and manufacturer Hitachi Zosen chose to redesign the machine’s seal system as part of their repair plan. Manufactured by Hitachi in Japan, the new seal system will be easier to access should the need arise. It will be installed in the coming weeks, along with other essential components designed to equip the machine for the remainder of its journey beneath Seattle. Other important elements of the repair plan include:
    • A new main bearing
    • Enhanced monitoring systems
    • Added steel to strengthen the machine and accommodate the new seal system 
    • Widened openings at the center of the cutterhead
    • Extended arms to mix excavated soil in the chamber behind the cutterhead
     
    Simulation showing additional steel to be installed in the SR 99 tunneling machine.      Crews installing additional steel in the SR 99 tunneling machine
    These images show the steel crews are adding to strengthen the tunneling machine.
     
    As owner of the tunneling machine, STP and Hitachi are responsible for all aspects of the repair effort, including the schedule. STP provides an updated schedule  to WSDOT each month, but the state cannot verify the schedule until work to resume tunneling is further along. We will continue to provide updates as we receive them.
     
    Digging into STP’s repair plan
    You can continue to track STP’s work on our time-lapse cameras and follow @BerthaDigsSR99 on Twitter for updates. Don't forget to check out the other resources we've created to give you a fuller understanding of Bertha's story:

     

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  • May 18 project update: Tunneling machine repairs and the release of new reports

    Seattle Tunnel Partners has confirmed that disassembly of the SR 99 tunneling machine is complete, and assessment of the damage is ongoing. They will not provide a revised schedule for resuming mining until they fully understand the scope of repairs.
     
    STP has indicated that they will replace the main bearing and outer seals of the machine as expected. They have also decided to replace the inner seals to make them more compatible with the new outer seals and easier to access should the need arise. The new inner seals were designed and manufactured in Japan and are scheduled to arrive in late May.
     
    Damage to the machine was more extensive in some areas than anticipated and some minor damage occurred during disassembly. For example, the outer seals and the steel retainers that hold them in place were destroyed. There was also damage to the cutter drive motor pinions and the main bearing bull gear.
     
    As owner of the tunneling machine, STP and Hitachi are responsible for all aspects of the repair effort. We will continue to provide updates as we receive them.
     
    Reports say natural influences, dewatering caused ground settlement near tunnel access pit
    Settlement levels remain steady six months after initial detection
     
    After months of study, experts agree: there are no simple answers regarding what caused the ground near the SR 99 tunnel access pit to settle approximately an inch last November. 
     
    Settlement near the pit and in the surrounding neighborhood was caused by a combination of historic and ongoing natural ground movement in the region, dewatering related to tunneling machine repair work and dewatering related to other construction in the area, according to two reports released Monday by the Washington State Department of Transportation. 
     
    One report, conducted by geotechnical firm Shannon & Wilson, Inc. and commissioned by WSDOT, concluded that dewatering related to tunneling machine repairs was the primary cause of the settlement. A second report , conducted by Brierley Associates and commissioned by tunnel contractor Seattle Tunnel Partners, concluded that natural settlement and other dewatering activities are the primary reasons for the settlement, and tunnel-related dewatering only contributed in areas immediately surrounding the pit. Both reports relied on the same data points.
     
    The issue began late last year, when the tunnel project’s monitoring system detected settlement in the vicinity of the 120-foot-deep pit STP built to access and repair the tunneling machine. In response to the settlement, WSDOT and STP increased the frequency of monitoring – which includes hundreds of instruments near the access pit – and assessed the viaduct and nearby buildings.
     
    Both reports demonstrate that settlement related to dewatering has since stabilized; they also agree the ground movement was minor and caused no structural damage. The Shannon & Wilson report, utilizing in part information from satellites, also identifies settlement in areas surrounding the project – in some cases, outside the ongoing monitoring area. Though satellite imagery is helpful to indicate trends, ground monitoring is the most reliable gauge of ground activity, which is why WSDOT’s monitoring program relies mostly on ground sensors throughout the project area.
     
    WSDOT and STP are continually evaluating ground conditions and taking proactive steps when needed to prevent further project-related settlement. That includes reviewing existing procedures for reducing dewatering should it become necessary. WSDOT has asked STP and city officials to work with project staff to further analyze the data and conclusions in the two reports to find consensus. The agency is also increasing monitoring in some areas and expanding the overall monitoring program in keeping with the analysis provided in the reports.
     
    Alaskan Way Viaduct Replacement Program Administrator Todd Trepanier made the following statement regarding the reports:
     
    “We all agree that public safety and protecting infrastructure are our top priorities. This is an incredibly complex issue, but all of us – the state, our contractor, the city – have a shared interest in reaching consensus and acting in the interest of public safety. Having reliable information is essential to any decision-making process. These studies will help inform future decisions about construction as we work to replace the viaduct.”
     
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  • Plan ahead: SR 99/Aurora Avenue North closures near South Lake Union this weekend

    Update: 10:45 p.m. Saturday, May 9 

    • All lanes in both directions have reopened.

    Travelers should plan ahead for closures on SR 99/Aurora Avenue North between the south end of the Battery Street Tunnel and Valley Street this weekend, May 8-10. The Alaskan Way Viaduct will remain open during this time.

    During the closures, crews will connect a new water main under the highway near Harrison Street – a critical step toward building the on- and off-ramp connections for the SR 99 tunnel’s future north portal. Seattle City Light crews will also take advantage of the closure to remove overhead power lines. 

    WSDOT is timing the closures to help Mariners fans get to and from the games this weekend. 

    SR 99/Aurora Avenue North closed between the south end of the Battery Street Tunnel and Valley Street

    • Southbound lanes
      • Closed from 10 p.m. Friday, May 8 to 5 a.m. Sunday, May 10
      • At least one lane will temporarily reopen from 3 to 10:30 p.m. Saturday, May 9

    • Northbound lanes
      • Closed from 11 p.m. Friday, May 8 to 5 a.m. Sunday, May 10
      • Both lanes will temporarily reopen from 8:30 to 10:30 p.m. Saturday, May 9

     

    Note: This post was originally published on April 28 at 3:59 p.m.

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  • May 8 project update: Latest Dispute Review Board Recommendation

    This week, the three-member board appointed by WSDOT and Seattle Tunnel Partners (STP) to assist in resolving contractual disputes issued its latest recommendation. The question before the board was narrow in scope: Was an eight-inch steel well-casing within the work zone adequately identified in the contract? The board determined that the well casing was clearly identified in contract documents, but that the contract documents did not clearly identify that the casing was made of steel.
     
    The Dispute Review Board recommendation states: “This recommendation is not to be considered as providing any information or merit related to the question of any impacts or cost that might have resulted from this obstruction. This recommendation only addresses the specific question of whether or not the eight-inch steel casing is a differing site condition under the contract.”
     
    Recommendations made by the board are not legally binding; they are simply one step in a prescriptive process designed to aid WSDOT and STP in resolving contractual disagreements. In addition to saying nothing about what damaged the tunneling machine, the recommendation does not assign any cost related to this issue.
     
    Alaskan Way Viaduct Replacement Program Administrator Todd Trepanier made the following statement:
     
    “It’s important to emphasize the specific question before the Dispute Review Board was narrow in scope and only addressed one issue: whether an existing eight-inch steel well-casing is a ‘differing site condition’ under the terms of the SR 99 tunnel contract. The hearing and subsequent recommendation did not deal with how the tunneling machine was damaged or the costs associated with repairs. The process of resolving disputes can be complicated and must follow the contract. WSDOT disagrees with the recommendation and does not consider this issue to be resolved. We are concerned with the reasoning used by the Dispute Review Board in reaching the recommendation. We are reviewing it and will continue to pursue the best interests of taxpayers as we determine the appropriate next steps.”
     
    Seattle Tunnel Partners Project Manager Chris Dixon made the following statement:
     
    “Seattle Tunnel Partners position was that the presence of the eight-inch diameter steel casing constituted a differing site condition under our contract with WSDOT. The Dispute Review Board’s recommendation supports and upholds Seattle Tunnel Partners’ position and represents one step in the prescribed process for resolving disputes under the contract. Seattle Tunnel Partners agrees with the recommendation. Seattle Tunnel Partners has advised WSDOT that Seattle Tunnel Partners has accepted the recommendation and considers this issue to be resolved.”

     

    Link to the board's full recommendation

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  • April 6 project update: Disassembly continues

    It’s been a busy week since Seattle Tunnel Partners lifted the SR 99 tunneling machine’s front end to the surface for repairs. Crews spent the first few days after the lift cleaning and disconnecting parts. Then, on Friday afternoon, they removed the machine’s bearing block and set it on a platform south of the cutterhead.
     
    Further disassembly will continue in the coming days, including removal of the main bearing. When the disassembly phase of STP’s repair effort is complete, manufacturer Hitachi Zosen will begin making repairs and enhancements (links to YouTube). You can continue to track STP’s work on our time-lapse cameras and follow @BerthaDigsSR99 on Twitter for updates. Don't forget to check out the other resources we've created to give you a fuller understanding of Bertha's story:
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  • New time-lapse video shows additional perspectives of Bertha lift

    The SR 99 tunneling machine's 2,000-ton front end has been safely on the ground for a couple of days, but it's worth revisiting how it got there. We created a video that shows the Bertha lift from three different perspectives. 

    Watch the Bertha lift time-lapse here (links to YouTube)

    You can continue to track STP’s work on our time-lapse cameras and follow @BerthaDigsSR99 on Twitter for updates. Don't forget to check out the other resources we've created to give you a fuller understanding of Bertha's story:

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  • March 31 project update: Bertha lift complete

    2:35 p.m. update: On Tuesday afternoon, Seattle Tunnel Partners safely placed the front end of the SR 99 tunneling machine on the repair platform located just south of the access pit. The set-down marked the end of a successful lift process that began early Monday. This time-lapse video shows the lift from a spot just north of the tunnel access pit.
     
    Crews will continue disassembling the machine’s 2,000-ton front end in the coming days, using the massive red crane that completed yesterday’s lift to arrange pieces on the repair site. Repair work will take place south of the pit beneath a large canopy that will soon be moved into place to protect the workers and machine pieces from the elements. 
     
    This was the fourth and final lift to bring pieces of the tunneling machine to the surface, a process explained in detail in our narrated video (links to YouTube). At 2,000 tons, this was also the largest lift crews undertook. In addition to the cutterhead, the newly removed drive unit section includes motors and parts that enable the cutterhead to rotate. It also houses the main bearing and seal system that will be replaced during repairs.
     
    You can continue to track STP’s work on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates. 
     
     

    ***

    On Monday, Seattle Tunnel Partners lifted the SR 99 tunneling machine’s front end from the access pit. The lifting process began early Monday morning with a series of tests to ensure the massive red crane performing the lift could handle the weight of the 2,000-ton section. The piece began rising from the pit around noon and was visible at the surface a few hours later. By 9 p.m., crews had positioned the piece above the platform where it will be set down for repairs.

    STP chose to wait until Tuesday morning to complete the lift with a fresh crew. You can track the conclusion of the lift on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates.

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  • March 30 project update: Lift of Bertha's 2,000-ton front end underway

    9:25 p.m. update: After a successful day of lifting, Seattle Tunnel Partners has chosen to wait until morning to place the SR 99 tunneling machine's front end on the repair platform. The piece will remain suspended above the platform until a fresh crew arrives in the morning to complete the lift.
     
    You can track the conclusion of the lift on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates.
     
    Crews will wait until Tuesday morning to place Bertha on the repair platform.
     

    ***

    6:30 p.m. update: Seattle Tunnel Partners is making good progress as they continue to lift the SR 99 tunneling machine’s front end to the surface for repairs. Crews began the lifting process early Monday morning with a series of tests to ensure the massive red crane performing the lift could handle the weight of the 2,000-ton section. The lift began around noon and the piece was visible at the surface a few hours later. 
     
    To expedite the lifting process, crews chose to rotate the section into a horizontal position as they hoisted it from the pit. When the rotation is complete, the crane will roll southward on its rails toward the specially made platform where the piece will be set down. The lift won’t likely be completed for several more hours, but there is no set schedule. Crews will take as long as necessary to safely lower the piece to the platform.
     
    You can track the action on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates.
     
         
    Bertha at the start of the lift.                        Bertha emerges from the pit.
     
    ***
     
    12:30 p.m. update: Seattle Tunnel Partners has begun lifting the SR 99 tunneling machine’s front end to the surface for repairs. A massive red crane began the lift – which includes the machine’s five-story-tall cutterhead – around noon Monday. Because the piece is so large, the lift could take 16 hours or longer, but there is no set schedule. Crews will take as long as necessary to safely complete the lift.
     
    You can track the action on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates.
     
    ***
     
    Seattle Tunnel Partners is getting ready to begin lifting the SR 99 tunneling machine’s 2,000-ton front end to the surface for repairs. The first step in the lifting process is to incrementally add weight to the crane to ensure it can safely complete the lift. Because the piece is so large, the entire lift process could take 16 hours or longer, but there is no set schedule. Crews will take as long as necessary to prepare for and execute the lift.
     
    In addition to the machine’s five-story-tall cutterhead, the section being lifted includes the motors and parts that enable the cutterhead to rotate. It also houses the main bearing and seal system that will be replaced during the repairs.
     
    The crane doing the lifting was built by Mammoet, a firm that has performed other large lifts around the world, including the successful recovery of a Russian nuclear submarine from the bottom of the Barents Sea. Equipped with nearly seven miles of steel cable, the crane bringing Bertha to the surface is capable of lifting more than 2,400 tons. Check out our time-lapse video (links to YouTube) showing the crane’s assembly.  
     
    This will be the fourth and final lift to bring pieces of the tunneling machine to the surface, a process our narrated video (links to YouTube) explains in detail. To date, crews have removed three pieces of Bertha’s exterior from the pit, the largest weighing 270 tons. The first lift, which occurred on March 19, can be seen from the perspective of the crane operator in this time-lapse video (links to YouTube).
     
    You can track the action on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates. We’ll also continue to post photos and videos as STP’s work progresses. 
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  • Weekend of SR 99 closures comes to a close

    MONDAY A.M. UPDATE: SR 99 through Seattle has reopened following a weekend of closures for highway construction and a regular inspection of the Alaskan Way Viaduct. SR 99 between the Battery Street Tunnel and Valley Street reopened at 1:30 a.m. Monday, March 30.

    SR 99 closure details
     
    7 p.m. Friday, March 27, until 5 a.m. Monday, March 30

    • Seattle Public Utilities crews will close two northbound lanes and one southbound lane of SR 99 between Ward Street and Highland Drive from 7 p.m. Friday to 5 a.m. Monday. 
    • WSDOT and SDOT contractor crews will close SR 99 between the Battery Street Tunnel and Valley Street from 10 p.m. Friday to 5 a.m. Monday.


    6 a.m. to 6 p.m. Saturday, March 28, and Sunday, March 29

    • WSDOT bridge inspection crews will conduct a scheduled inspection of the Alaskan Way Viaduct between South Spokane Street and the Battery Street Tunnel.


    Westbound I-90 closure

    The SR 99 closures are part of a busy weekend of highway construction in the region. Drivers heading across Lake Washington from the Eastside will see westbound Interstate 90 detoured to the express lanes as crews upgrade tunnel operations systems inside the westbound Mount Baker and Mercer Island tunnels.

    11 p.m. Friday, March 27, until 5 a.m. Monday, March 30

    • Contractor crews will shift all westbound I-90 traffic between Bellevue Way and Rainier Avenue South to the express lanes from 11 p.m. Friday to 5 a.m. Monday. 
    • Drivers wishing to access Mercer Island will need to exit westbound I-90 at East Mercer Way. There are no westbound exits to Mercer Island from the express lanes. 
    • Those wishing to travel from Mercer Island to Seattle should enter the express lanes at 77th Avenue Southeast or Island Crest Way. 
    • Westbound I-90 drivers will be unable to exit to Rainier Avenue South and should follow the signed detour via Fourth Avenue South and South Dearborn Street. 
    • Drivers needing to transport flammable materials westbound across Lake Washington must use alternate routes such as Interstate 405 or state routes 520 or 522. 
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  • March 27 project update: Final lift approaches

    Seattle Tunnel Partners is nearly ready to lift the SR 99 tunneling machine’s front end to the surface for repairs. On Thursday, the massive red crane that will make the lift was rolled into place above the tunnel access pit. Crews are now connecting rigging and will spend the weekend making final preparations to lift the 2,000-ton piece to the surface. In addition to the machine’s five-story-tall cutterhead, the section being lifted includes the motors and parts that enable the cutterhead to rotate. It also houses the main bearing and seal system that will be replaced during the repairs.
     
    Because the piece is so large, the lift could take 16 hours or longer, but there is no set schedule. Crews will take as long as necessary to prepare for and safely complete the lift. The crane doing the lifting was built by Mammoet, a firm that has performed similar lifts around the world, including the successful recovery of a Russian nuclear submarine from the bottom of the Barents Sea. Equipped with nearly seven miles of steel cable, the crane bringing Bertha to the surface is capable of lifting more than 2,400 tons. Check out our time-lapse video (links to YouTube) showing the crane’s assembly.  
     
    This will be the fourth and final lift in STP’s repair effort, which our narrated video (links to YouTube) explains in detail. To date, crews have removed three pieces of Bertha’s exterior from the pit, the largest weighing 270 tons. The first lift, which occurred on March 19, can be seen from the perspective of the crane operator in this time-lapse video (links to YouTube).
     
    You can track the action on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates. We’ll also continue to post photos and videos as STP’s work progresses.
     
     
    The crane that will lift the tunneling machine's front end to the surface rolled into position on Thursday.
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  • March 23 project update: Third piece of tunneling machine lifted to the surface

    Seattle Tunnel Partners has successfully lifted the third piece of the SR 99 tunneling machine to the surface for repairs. Crews lifted the machine’s 90-ton right side body from the pit Monday afternoon. Like the previous two pieces removed from the pit, the right side body is part of the machine's exterior shield.

    The first lift, which occurred last week, can be seen from the perspective of the crane operator in this time-lapse video (links to YouTube).

    With the machine's upper shield removed, STP will turn their attention to the final lift: Bertha's massive cutterhead and main drive unit. Crews will use the giant red crane, called a modular lift tower, to make the 2,000-ton lift. This narrated video (links to YouTube) explains the repair plan in detail.  

     

    Crews lifted Bertha’s 90-ton right side body from the pit on Monday.

    Three pieces of Bertha's shield have been brought to the surface for repairs. 

    You can track the action on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates. We’ll also continue to post photos and videos as STP’s work progresses. 

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  • March 21 project update: Second piece of tunneling machine lifted to the surface

    Seattle Tunnel Partners has successfully hoisted the second piece of the SR 99 tunneling machine to the surface for repairs. This evening crews lifted one of the machine's upper sections, which weighs less than 100 tons.
     
    Two more pieces of the machine will be removed from the pit as part of STP’s repair plan, which this narrated video (links to YouTube) explains in detail. Up next, crews will lift the right side body section of the machine, which weighs approximately 90 tons. The final lift will bring to the surface Bertha’s massive cutterhead and main drive unit, which weigh a combined 2,000 tons.
     
    You can track the action on our time-lapse camera and follow @BerthaDigsSR99 on Twitter for updates. We’ll also continue to post photos and videos as STP’s work progresses.

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  • Plan ahead: SR 99 closures set for weekend of March 27

    Highway construction, utility work and a regular inspection of the Alaskan Way Viaduct will close portions of SR 99 through Seattle during the weekend of March 27-29. Lane closures along both directions of SR 99 begin at 7 p.m. Friday, March 27. By 10 p.m., SR 99 will be closed between the south end of the Battery Street Tunnel and Valley Street until 5 a.m. Monday, March 30.

    SR 99 closure details
     
    7 p.m. Friday, March 27, until 5 a.m. Monday, March 30

    • Seattle Public Utilities crews will close two northbound lanes and one southbound lane of SR 99 between Ward Street and Highland Drive from 7 p.m. Friday to 5 a.m. Monday. 
    • WSDOT and SDOT contractor crews will close SR 99 between the Battery Street Tunnel and Valley Street from 10 p.m. Friday to 5 a.m. Monday.


    6 a.m. to 6 p.m. Saturday, March 28, and Sunday, March 29

    • WSDOT bridge inspection crews will conduct a scheduled inspection of the Alaskan Way Viaduct between Spokane Street and the Battery Street Tunnel.


    Westbound I-90 closure

    The SR 99 closures are part of a busy weekend of highway construction in the region. Drivers heading across Lake Washington from the Eastside will see westbound Interstate 90 detoured to the express lanes as crews upgrade tunnel operations systems inside the westbound Mount Baker and Mercer Island tunnels.

    11 p.m. Friday, March 27, until 5 a.m. Monday, March 30

    • Contractor crews will shift all westbound I-90 traffic between Bellevue Way and Rainier Avenue South to the express lanes from 11 p.m. Friday to 5 a.m. Monday. 
    • Drivers wishing to access Mercer Island will need to exit westbound I-90 at East Mercer Way. There are no westbound exits to Mercer Island from the express lanes. 
    • Those wishing to travel from Mercer Island to Seattle should enter the express lanes at 77th Avenue Southeast or Island Crest Way. 
    • Westbound I-90 drivers will be unable to exit to Rainier Avenue South and should follow the signed detour via Fourth Avenue South and South Dearborn Street. 
    • Drivers needing to transport flammable materials westbound across Lake Washington must use alternate routes such as Interstate 405 or state routes 520 or 522. 
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  • March 19 project update: First piece of Bertha removed from the access pit Thursday

    Seattle Tunnel Partners has successfully hoisted the first piece of the SR 99 tunneling machine to the surface for repairs. Crews lifted the machine's 270-ton upper body to the surface on Thursday afternoon.
     
    Three more pieces of the machine will be removed from the pit as part of STP’s repair plan, which this narrated video  (links to YouTube) explains in detail. Up next, crews will lift the upper right and upper left sections of the machine – both of which weigh less than 100 tons. The final lift will bring to the surface Bertha’s massive cutterhead and main drive unit, which weigh a combined 2,000 tons. 
     
    Keep watching our time-lapse camera and following @BerthaDigsSR99  on Twitter for updates. 
     
     
    Crews lifted Bertha's 270-ton upper body from the pit on Thursday.
     
     
    A shot of Bertha in the pit following the lift. 
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  • March 17 project update: Preparing to lift Bertha from the access pit

    As disassembly of the SR 99 tunneling machine continues, Seattle Tunnel Partners is readying the area to the south of the access pit, where the machine pieces will be set down and repaired. 
     
    Crews have erected the metal frame for the large canopy that will protect workers and machine parts from the elements during repairs. The frame is already visible to traffic passing by on SR 99, but it will be even easier to spot when crews install the canopy atop the frame later this month.
     
     
    This large metal frame is part of the canopy that will protect workers and machine parts from the elements during repairs.
     
    Meanwhile, STP has told us crews may lift the first of four pieces of the machine’s front end to the surface as soon as this week. Crane operators are adding the final pieces to the massive red crane that will lift the cutterhead and drive unit, as illustrated in STP’s repair video (links to YouTube). Before that happens, a crawler crane will remove smaller pieces of the machine from the pit. 
     
    Inside the machine, crews are disconnecting hoses and cables, and have already removed eight of Bertha’s 24 motors. Removing these eight motors will give crews the clearance they need to lift the cutterhead and drive unit to the surface. The remaining 16 motors, which weigh approximately 8,000 pounds apiece, will remain attached and be removed from the pit as part of the cutterhead lift.
     
    You can track the action on our construction cameras. We’ll also continue to post photos and videos as STP’s work progresses.
     
    Repair plan resources:

     

    Previous updates

    March 3, 2015 afternoon update - Disassembly begins

    Feb. 26, 2015 afternoon update - Bertha's next move

    Feb. 20, 2015 afternoon update - Tidying up the launch pit

    Feb. 19, 2015 morning update - Bertha reaches daylight

    Feb. 19, 2015 morning update - Bertha approaching the pit

    Feb. 18, 2015 afternoon update - Bertha digs on

    Feb. 18, 2015 project update - Bertha on the move

    Archive of previous updates

     

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  • Postponed: Long-term lane closures on SR 99/Aurora Avenue North

    We are postponing plans for long-term lane closures on SR 99/Aurora Avenue North originally scheduled to begin on Wednesday, March 11. These closures were needed to install several large sign foundations for the SR 99 North Access project. While this work must occur, it will be rescheduled to a later date in an effort to minimize impacts to the traveling public. The public will be alerted in advance of any future lane closures.

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  • March 3 project update: Disassembly begins

    Bertha reached her stopping point in the SR 99 tunnel access pit on Tuesday night, clearing the way for Seattle Tunnel Partners to begin a disassembly process that will likely take weeks.
     
    Bertha moved forward a total of 57 feet between Feb. 17, when mining resumed, and yesterday. Along the way she built nine permanent concrete tunnel rings, which aren’t visible in the pit because they’re obscured by the ground and the machine’s exterior.
     
     
    With Bertha now in position, crews have begun the challenging task of taking apart the world’s largest tunneling machine. They will move through a number of methodical steps as they prepare to lift four pieces weighing up to 2,000 tons to the surface for repairs. Among other things, they must disconnect hundreds of hoses and cables, remove motors and weld lift points to the machine’s exterior.
     
    When disassembly is complete, a massive red crane (links to YouTube) will move into position above the pit. Several pieces of the machine will be removed before the cutterhead is lifted out of the pit, as illustrated in STP’s repair video (links to YouTube). 
     
     
    This Wednesday morning photo of Bertha in the pit was taken by our time-lapse camera.
     
    Repair plan resources:

     

    Previous updates

    Feb. 26, 2015 afternoon update - Bertha's next move

    Feb. 20, 2015 afternoon update - Tidying up the launch pit

    Feb. 19, 2015 morning update - Bertha reaches daylight

    Feb. 19, 2015 morning update - Bertha approaching the pit

    Feb. 18, 2015 afternoon update - Bertha digs on

    Feb. 18, 2015 project update - Bertha on the move

    Archive of previous updates

     

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  • Hot Chocolate Run to close a portion of SR 99 on Sunday morning

    City of Seattle crews will close SR 99 in both directions from 6 a.m. to 11 a.m. Sunday, March 1 between the south end of the Battery Street Tunnel and North 47th Street as part of the Hot Chocolate Run

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  • Feb. 26 project update: Bertha’s next move

    After taking a break from mining to clean up the mixture of dirt, concrete and water that came into the access pit during last week’s breakthrough, Seattle Tunnel Partners has resumed Bertha’s final approach into the pit. 
     
    Because the cutterhead has made it through the pit wall, there isn’t any digging left to do. The focus now is on building the concrete tunnel rings that enable the machine to move forward. Bertha must build five more rings – a process that’s explained visually in this animation (links to YouTube) – before she comes to rest near the northern edge of the pit. Bertha will continue to take breaks so crews can clean up debris.
     
    When the machine reaches its destination, crews will begin disassembling the machine and preparing to lift pieces to the surface for repair. STP has said this process will take significant time and effort because it involves a number of steps. These steps include:
     
    • Installing work areas around the machine
    • Disconnecting joints, cables and hoses
    • Removing cutting tools and other parts from the cutterhead
    • Welding lift points on the body of the machine


    When the disassembly process is complete, a massive red crane (links to YouTube) will move into position. Several pieces of the machine will be removed from the pit before the cutterhead, as illustrated in STP’s repair video (links to YouTube). 

    We’ll continue to keep you posted as STP’s work moves forward. Remember to visit our access pit camera and follow Bertha on Twitter for the latest information.
     

    Crews clean up debris in the access pit.
     
    Repair plan resources:

     

    Previous updates

    Feb. 20, 2015 afternoon update - Tidying up the launch pit

    Feb. 19, 2015 morning update - Bertha reaches daylight

    Feb. 19, 2015 morning update - Bertha approaching the pit

    Feb. 18, 2015 afternoon update - Bertha digs on

    Feb. 18, 2015 project update - Bertha on the move

    Archive of previous updates

     

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  • Feb. 20 update: Tidying up the access pit

    After a few days of steady digging, Seattle Tunnel Partners is taking a break from mining so crews can clean out the bottom of the access pit. As expected, a mixture of dirt, concrete and water came into the pit along with the tunneling machine during Thursday’s breakthrough. Crews are using vacuum trucks and other tools to remove the material. 
     
    Once Bertha’s cradle is cleaned off, crews will continue moving the machine forward. Bertha must travel an additional 35 feet before STP and manufacturer Hitachi Zosen can begin the disassembly process. Since mining resumed late Tuesday, Bertha has moved nearly 22 feet.
     

    Repair plan resources:

     

    Previous updates

    Feb. 19, 2015 morning update - Bertha approaching the pit

    Feb. 18, 2015 afternoon update - Bertha digs on

    Feb. 18, 2015 project update - Bertha on the move

    Feb. 13, 2015 project update - Safety at the forefront

    Feb. 13, 2015 project update - Long-term traffic impacts on SR 99: lane closure begins March 7 through late May

    Feb. 12, 2015 - Incident at tunnel's north portal work zone

    Feb. 9, 2015 project update - Cradle awaits Bertha's front end

    Archive of previous updates

     

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  • Feb. 19 afternoon update: Bertha reaches daylight

    At midday Thursday, the top portion of the SR 99 tunneling machine’s cutterhead broke through (links to YouTube) the southern wall of the access pit. Crews will continue to mine an additional two feet before stopping to build another concrete tunnel ring.

    This is just the beginning of the repair effort being led by Seattle Tunnel Partners and manufacturer Hitachi Zosen. The machine will continue to move forward in 6 ½ foot increments, stopping to build rings on its way into the pit. When the front end of the machine is fully exposed, crews will begin the disassembly process. STP has told us that taking the machine apart and lifting it to the surface will take significant time and effort.

    We recognize that the public has great interest in STP’s repair effort. We will continue to provide photos, video and regular updates about their progress as they work to resume tunneling. 

    Repair plan resources:

     

    Previous updates

    Feb. 19, 2015 morning update - Bertha approaching the pit

    Feb. 18, 2015 afternoon update - Bertha digs on

    Feb. 18, 2015 project update - Bertha on the move

    Feb. 13, 2015 project update - Safety at the forefront

    Feb. 13, 2015 project update - Long-term traffic impacts on SR 99: lane closure begins March 7 through late May

    Feb. 12, 2015 - Incident at tunnel's north portal work zone

    Feb. 9, 2015 project update - Cradle awaits Bertha's front end

    Archive of previous updates

    — more —
  • Feb. 19 morning update: Bertha approaching the pit

    Since yesterday afternoon's update, Seattle Tunnel Partners has built two new concrete tunnel rings and continued mining into the southern wall of the SR 99 tunnel access pit. Bertha has travelled 14 feet since mining resumed late Tuesday evening, and work is proceeding as planned. 
     
    Here's video footage (links to YouTube) of Wednesday's work. Crews from STP and manufacturer Hitachi Zosen are continuing to use caution to protect the machine from overheating or further damage as they mine through 20 feet of unreinforced concrete to reach the interior of the pit.
     
    Repair plan resources:

     

    Previous updates

    Feb. 18, 2015 afternoon update - Bertha digs on

    Feb. 18, 2015 project update - Bertha on the move

    Feb. 13, 2015 project update - Safety at the forefront

    Feb. 13, 2015 project update - Long-term traffic impacts on SR 99: lane closure begins March 7 through late May

    Feb. 12, 2015 - Incident at tunnel's north portal work zone

    Feb. 9, 2015 project update - Cradle awaits Bertha's front end

    Archive of previous updates

    — more —
  • Feb. 18 afternoon update: Bertha digs on

    Since mining resumed at 10:15 p.m. Tuesday, Bertha has successfully moved forward more than six feet and work is progressing as planned. Crews stopped mining this afternoon to begin building the SR 99 tunnel’s 151st concrete ring. Mining will resume after the ring has been built.  

    Seattle Tunnel Partners and tunneling machine manufacturer Hitachi Zosen are continuing to follow strict protocols as they mine through the access pit’s southern wall. These protocols are designed to prevent overheating or further damage to the machine as it mines through 20 feet of unreinforced concrete to reach the interior of the pit.

    We continue to closely monitor the surrounding area as this work proceeds. 
     

    Previous updates

    Feb. 18, 2015 project update - Bertha on the move

    Feb. 13, 2015 project update - Safety at the forefront

    Feb. 13, 2015 project update - Long-term traffic impacts on SR 99: lane closure begins March 7 through late May

    Feb. 12, 2015 - Incident at tunnel's north portal work zone

    Feb. 9, 2015 project update - Cradle awaits Bertha's front end

    Jan. 30, 2015 project update

    Archive of previous updates

    — more —
  • Feb. 18 project update: Bertha on the move

    Last night, Seattle Tunnel Partners began mining through the southern wall of the SR 99 tunnel access pit. As of 7 a.m. on Feb. 18, Bertha, the SR 99 tunneling machine, had moved more than three feet. 
     
    The machine must mine through 20 feet of unreinforced concrete to reach the pit. The duration of this effort will depend on the machine’s ability to mine through the concrete while operating with a damaged seal system. STP anticipates the machine may overheat, as it has during their most recent attempts at mining. If the machine becomes too hot, they will take a break for it to cool down before resuming. 
     
    Work to chip away a Bertha-sized circle on the face of the pit’s southern wall wrapped up yesterday. This allows for a cleaner breakthrough when the machine moves into the pit. Watch a video (links to YouTube) of the work.
     
    Moving Bertha into the pit is just the beginning of the repair process, which this narrated video (links to YouTube) explains in detail. The machine must be partially disassembled before it can be lifted to the surface, a process that STP has said will likely take significant time and effort. 
     
    We recognize that the public has great interest in the outcome of STP’s repair effort, and we are committed to providing regular updates on Twitter and our website as their work moves forward.
     

     

    — more —
  • Feb. 13 project update: Safety at the forefront

    Thursday’s incident at the north portal has safety on everyone’s mind as Seattle Tunnel Partners enters a new phase of its effort to resume tunneling. In addition to wishing those injured a speedy recovery, we want to reiterate our commitment to safety in all aspects of our work. This is, after all, a safety project. 
     
    Fixing Bertha is important. Building the tunnel portals is important. Keeping the project moving is important. But nothing is more important than the safety of our workers and the public. That’s something that always has been, and will continue to be, at the core of everything we do. 
     
    Getting ready to move Bertha
     
    STP is making final preparations for Bertha’s move into the 120-foot-deep pit that will allow crews to hoist the machine to the surface for repairs. STP has spent the past few days injecting grout into the ground and installing new drains alongside the machine. These measures will help crews control groundwater as Bertha slowly moves forward through the wall of the pit, an effort that STP plans to begin sometime in the next week.
     
    STP may begin preparing the shaft wall for Bertha’s breakthrough even before the machine starts mining. Starting as soon as this weekend, crews plan to use heavy equipment to chip away the portion of the pit’s southern wall where Bertha will eventually emerge. This process is similar to scoring a surface before you cut into it, and will allow the concrete to break away in a controlled manner when Bertha finally moves into the pit.
     
    Approximately 20 feet of unreinforced concrete stands between Bertha and daylight. The duration of Bertha’s dig will depend on her ability to mine through and digest concrete while operating with a damaged seal system. STP expects Bertha to overheat, as she has during their most recent attempts at mining. They will likely mine until the machine becomes too hot, then take a break. To speed up the move, crews may choose to continue chipping their way toward Bertha from within the pit during times when the machine is cooling off.
     
    Moving Bertha into the pit is just the beginning of the repair process, which this narrated video (links to YouTube) explains in detail. The machine must be partially disassembled before it can be lifted to the surface, a process that will likely take significant time and effort. We will provide regular updates on Bertha’s progress as soon as she starts moving.
     
     
    Crews prepare the area where Bertha will emerge for repairs.
     
     
    The view from the bottom of the 120-foot-deep access pit.
     
    Time-lapse video shows crane construction
     
    Crews have spent the past several months assembling the massive red crane that will lift Bertha to the surface. As STP prepares to move the machine into the pit, crane crews are also making final preparations. This time-lapse video illustrates how the crane came to be, and this post explains the assembly process in more detail. Don’t forget about our time-lapse cameras, which will give you a good view of STP’s work to repair Bertha. 
     

    This massive red crane will lift Bertha to the surface for repairs.
     
    Minor viaduct settlement measured, but no new risks
     
    Survey crews have confirmed that the Alaskan Way Viaduct between South Main Street and Railroad Way South has settled up to ¼ inch in the past month. Our bridge experts are confident this minor, uniform settlement does not pose any new safety risks to the public. The viaduct remains vulnerable to earthquakes, but it is still safe for everyday use. If we had any reason to believe the structure was unsafe, we would not hesitate to close it.
     
    These latest measurements only apply to this section of the viaduct. We have not measured any similar trends elsewhere on the viaduct, in nearby buildings or the ground surface. We expect the viaduct will continue to experience minor settlement until it is removed. Viaduct settlement has made headlines in recent months, but it’s important to remember that this isn’t a new issue. The viaduct has been settling for years, as you can see in our inspection log. Hundreds of monitors have been installed in the ground and on the viaduct to help us monitor settlement, and we will continue to keep a close eye on the structure’s condition as construction continues.
     
    This post explains some of the things we’ve done over the years to keep the viaduct safe for everyday use.
     

     

    — more —
  • Incident at tunnel's north portal work zone

    Feb. 13, 11:40 a.m. UPDATE - Statement from Seattle Tunnel Partners: 

    At the SR 99 tunnel’s north portal, Seattle Tunnel Partners is continuing with its investigation of the safety incident involving five ironworkers who were installing rebar for a concrete wall on Thursday afternoon. STP is thankful that four of the workers were not seriously injured. The fifth worker is currently receiving medical treatment at Harborview Medical Center. While work is proceeding at the north portal, it is not proceeding in the area where the workers were injured, as the investigation of the safety incident is ongoing. Seattle Tunnel Partners is very proud of its safety program and safety record on the SR 99 Tunnel Project, which focuses on creating safe work conditions and eliminating unsafe work practices and at-risk work behaviors. STP takes every safety incident very seriously. As with every safety incident, STP will investigate this safety incident to determine the cause(s) and to identify the corrective action(s) to be implemented to prevent the reoccurrence of the same or similar safety incident in the future.

    Chris Dixon

    Seattle Tunnel Partners Project Manager

    Feb. 12, 3:33 p.m. UPDATE - Statement from Seattle Tunnel Partners: This afternoon, five workers were installing rebar for a concrete wall at the tunnel's north portal work zone. The wall of rebar gave way, injuring four of the five workers. The injured workers were transported to Harborview Medical Center for evaluation. Emergency procedures were followed throughout the incident. Seattle Tunnel Partners is thankful for the Seattle Fire Department’s assistance in evacuating the injured workers to Harborview. 

    Feb. 12, 2:36 p.m. - Initial statement from WSDOT: We are still gathering information, but Seattle Tunnel Partners has informed us that an incident has occurred on the SR 99 Tunnel Project job site in the north portal area. Safety is STP’s and WSDOT's number one priority. Right now, their field crews are focusing on making sure the site is secured. Emergency services were notified immediately and arrived on site after the incident.

    We will provide additional information as it becomes available.  

    — more —
  • Feb. 9 project update: Cradle awaits Bertha’s front end

    After completing access pit excavation late last month, Seattle Tunnel Partners’ crews turned their attention to building the concrete cradle at the bottom of the pit. Over the last week, they placed several base layers, formed the cradle with rebar and poured nearly 1,000 cubic yards of concrete to complete the cradle on Sunday, Feb. 8. The cradle will support the machine after it moves through the pit’s southern wall, which is about 20 feet thick.

    The next step is to tunnel through the concrete wall. The length of time it takes Bertha to reach the pit will depend largely on her ability to mine through and digest the concrete. If she’s unable to mine through the wall, STP will create an opening from within the pit to give her an unobstructed path forward. Once inside the pit, crews will prepare the machine for disassembly and use the massive red gantry crane to hoist the front end of the machine to the surface for repairs. This narrated video (links to YouTube) explains the repair process in detail.

    Previous updates

    Jan. 30, 2015 project update

    Jan. 27, 2015 project update

    Jan. 22, 2015 project update

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  • Jan. 30 project update: Access pit excavation complete

    Seattle Tunnel Partners has completed excavation of the 120-foot-deep pit that will be used to access and repair Bertha, the SR 99 tunneling machine. Crews removed the final scoop of soil from the pit on Friday, Jan. 30. Approximately 20,000 cubic yards of material was removed from the ground over the course of excavation, which began in mid-October. 
     
    With excavation complete, crews can begin construction of the concrete cradle at the bottom of the pit. The cradle will support the machine after it moves through the pit’s southern wall, which is about 20 feet thick. 
     
    STP plans to tunnel through the concrete wall. The length of time it takes Bertha to reach the pit will depend largely on her ability to mine through and digest the concrete. If she’s unable to mine through the wall, STP will create an opening from within the pit to give her an unobstructed path forward. Once inside the pit, crews will use the massive red gantry crane pictured below to hoist the front end of the machine to the surface for repairs. This narrated video (links to YouTube) explains the repair process in detail. You can also watch raw video of pit excavation on YouTube.  
     
     
    The dewatering system that controls groundwater in the pit will continue to operate at its current level as STP proceeds with its repair work. Settlement levels near the pit remain stable.
     
    Crews building the highway inside the tunnel are also preparing for a big milestone: the first concrete pour on what will become the southbound lanes of the tunnel. Here’s what the southbound roadway currently looks like:
     
     

     

    — more —
  • Jan. 27 project update

    Last week, we shared with the public that the dispute review board for the SR 99 tunnel contract had heard and made recommendations on a request by Seattle Tunnel Partners for a differing site condition at the tunnel launch pit. A differing site condition can occur when: 1) actual subsurface or latent physical conditions encountered at the site differ substantially or materially from those indicated in the contract, or 2) unknown conditions at the site are unusual in nature and differ materially from those ordinarily encountered in the type of work.
     
    To clarify, this dispute is related to a differing site condition experienced while building the launch pit; it is not related to the stoppage of the tunneling machine or recent settlement near the access pit. And, there are funds set aside within the existing project budget to deal with differing site conditions.
     
    There has been interest from the public in being able to review the board’s recommendations, which are attached to this WSDOT memorandum (pdf 880 kb). Because these recommendations are technical in nature, there may be questions about what they mean.
     
    As we review the board’s recommendations on the differing site condition in the launch pit and determine our next steps, we will use the terms in the contract to reach the best possible outcome for taxpayers as we continue to build this critical safety project. We will not be offering our opinions of the board’s recommendations or speculating on next steps until our analysis is complete.
     
    It is also important to remember that the board’s recommendations are just that, recommendations. They are not binding. While STP requested $20 million in compensation for this differing site condition, the board’s recommendations did not address the cost and schedule impacts. Thus it is too early to speculate as to the cost and schedule impacts of this recommendation, should it be accepted by WSDOT.
     

     

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  • Jan. 22 project update

    It is not uncommon for disputes to arise between owners and contractors during a construction project. One way to resolve disagreements is through a dispute review board. The review board, a panel of three experts chosen by the parties jointly, reviews the facts of a dispute and makes recommendations to the owner and contractor. The SR 99 Tunnel Project contract between WSDOT and Seattle Tunnel Partners established a dispute review board.
     
    In 2013, the board heard arguments related to STP’s request for a change order for work associated with strengthening the Alaskan Way Viaduct in advance of tunneling under it. WSDOT denied this request and the board issued a recommendation that was consistent with WSDOT’s denial. STP may pursue reconsideration, which is allowed under the contract.
     
    In late 2012, Seattle Tunnel Partners requested a change order for an alleged differing site condition in the launch pit at the south portal. STP’s request was for $20 million. WSDOT rejected this request. Last year, both WSDOT and STP agreed to ask the board to make a recommendation and the matter was heard in October.
     
    To clarify, this dispute is related to a differing site condition experienced while building the launch pit; it is not related to the stoppage of the tunneling machine or recent settlement near the access pit. And, there are funds set aside within the existing project budget to deal with differing site conditions.
     
    On Jan. 16, the board submitted its recommendation, which stated in part that a “differing site condition was encountered in the glacial soils and that STP is entitled to relief” to the extent it incurred costs or delays because of that condition. The board did not determine what costs or delays were caused by the differing site condition it identified. STP promptly sent a letter accepting the board’s recommendation.
     
    We are still reviewing the board’s recommendation. As a reminder, the board’s recommendations are just that, recommendations. If WSDOT or STP disagrees with a recommendation, either party can ask for reconsideration or simply move to the next process allowed under the contract. The next steps will be determined after our analysis is completed. 
     

     

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  • Nighttime lane closures on SR 99/Aurora Avenue North near South Lake Union

    Seattle drivers should plan for possible overnight delays next week on State Route 99/Aurora Avenue North between Queen Anne Hill and Lake Union.

    Closure details

    • From Monday, Jan. 26, through the morning of Friday, Jan. 30, crews will close up to two lanes in each direction of SR 99/Aurora Avenue North between Valley and Halladay streets from 8 p.m. to 6 a.m. each night.

    During the closures, construction crews working for the Washington State Department of Transportation will continue work to locate existing utilities in advance of upcoming installation of overhead signs.

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  • Jan. 12 project update

    We want to clarify media reports that may have left you with the impression that the SR 99 tunnel access pit is unsafe. Despite what you may have seen or read, at no time has there been a “risk of catastrophic failure” due to excavation of the access pit.
     
    Last week, the Seattle Department of Transportation and Seattle Public Utilities sent WSDOT a letter with concerns about construction and dewatering of the pit that will be used to access and repair the tunneling machine.
     
    The City’s letter compares sentences from draft Dec. 11 and final Dec. 19 letters written by Seattle Tunnel Partners’ Engineer of Record on the access pit. These letters were between the contractor and its sub-contractor. An Engineer of Record’s role is to prepare a design and help assess potential risks for any work on a contract and make recommendations on ways to address those risks so they don’t materialize.
     
    Before access pit construction began, STP and their Engineer of Record agreed to inspection procedures to verify the quality of the access pit work as excavation progressed to 90 feet below the ground surface. Procedures for excavation below 90 feet had not been agreed upon in December; they have since been finalized.
     
    The Engineer of Record sent a draft letter to STP on Dec. 11 starting a technical conversation between the two parties about whether their current procedures needed to be adjusted for excavation below 90 feet. Both agreed that the procedures needed to be adjusted. The Engineer of Record then revised their draft letter and sent a final version on December 19 that stated excavation may not proceed until new procedures are adopted. This is a routine work and risk assessment process. 
     
    At no time did the Engineer of Record state that there was an existing “risk of catastrophic failure” due to access pit excavation. The correspondence describes what steps STP must continue to take to assure that they adequately address risk for the balance of the work.
     
    STP is excavating and verifying their work in a manner that is consistent with the direction from their Engineer of Record – otherwise they would not be allowed to continue. This is a design-build contract which puts the responsibility of design and construction on the contractor. WSDOT’s role is to assure the terms of contract are met and to verify the quality of the work.
     
    Our first priority is safety – period. At no time has the Alaskan Way Viaduct or the access pit been at risk due to excavation. The viaduct remains safe for vehicle travel.
     
    WSDOT and the City have a shared commitment to public safety and to improve communication. We are in constant contact with representatives from SDOT and other departments at the City. We have provided access to all of our data and have weekly meetings where they can raise questions about the data they are receiving.
     
    The City has access to real-time information, and we will work with the City to establish more specific protocols so that when there are questions about a project activity we both share data, expertise and context.
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  • Jan. 8 project update: Access pit construction progressing

    The new year is off to a busy start as we continue our work to replace the Alaskan Way Viaduct. After spending the past two weeks performing work on the walls of the SR 99 tunnel access pit, Seattle Tunnel Partners resumed excavation of the pit this morning. Crews will continue to alternate between digging and adding grout to the pit’s walls. Currently 90 feet deep, the pit will be 120 feet deep when complete.     
     
    Settlement levels near the pit have remained stable for more than six weeks. We are monitoring ground conditions closely, while remaining in regular communication with neighbors and property owners in the area. Our team has now completed 57 building surveys since crews first confirmed settlement near the pit in early December. To date, no structural damage has been found.
     
    Most major elements of the crane that will lift the front end of the tunneling machine to the surface are now in place. STP plans to begin testing the crane later this month.
     
    Crane photo
     
    Regarding the overall schedule, we still cannot endorse a project completion date until STP’s work to resume tunneling is further along. The tunnel contract was designed to protect Washington taxpayers, in part because it includes this vital component: Creating and maintaining the project schedule is STP’s responsibility. Our responsibility is to hold them accountable for their work, a task that remains our focus as we begin 2015. 
     
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