Alaskan Way Viaduct Replacement Project Update – September 2014

BerthaMilepost 31 Speaker Series

Bertha and Progress on the SR 99 Tunnel Project

Seattle Tunnel Partners, the contractor hired by WSDOT to design and build the SR 99 tunnel, is working to repair the SR 99 tunneling machine. Join us to learn more about STP’s plan to resume tunneling by the end of March 2015, and learn about the other work happening to replace the viaduct.

6 – 6:30 p.m.
Friday, Sept. 5
Milepost 31, 211 First Ave. S., Seattle
Admission is free.

 

Seattle Tunnel Partners progress update: Construction of the access pit’s underground walls wraps up, preparation for dewatering begins

With fall just around the corner, we thought it was time for an update on Seattle Tunnel Partners’ progress to build the circular pit (pdf 2.5 Mb) that crews will use to access and repair the SR 99 tunneling machine.

The last time we updated you, STP announced that crews would continue to install the underground walls of the access pit through August. STP has notified WSDOT that they have completed all of the piles for the circular pit. Additional piles will be installed near the pit as part of the support system for the modular lift tower – the large crane that will hoist the machine’s 2,000-ton cutterhead and drive unit out of the ground.

Next up, dewatering wells. STP has notified us that crews will install several dewatering wells both inside the access pit and inside the enclosed area south of the access pit around the tunneling machine. Prep work is beginning now and crews should have them installed by mid-September. These wells will lower the groundwater inside the enclosed areas to make it easier to move the tunneling machine into the access pit, as well as to excavate the pit.

STP has notified us that tunneling machine operators will start Bertha in order to check internal systems in preparation for mining into the circular pit. Also, pieces of the three cranes that will be used to lift tunneling machine pieces out of the access pit are continuing to arrive from around the world. Soon you will see these pieces being assembled next to the access pit.

STP still expects to resume tunneling in March 2015. For a better view of construction, check out our time-lapse camera, or view photos of recent construction on Flickr.

Additional resources

Alaskan Way Viaduct Replacement Program News – August 2014

BerthaTopics:

Bertha update – Construction of the access pit’s underground walls will continue through August

Earlier this week, Seattle Tunnel Partners notified us that building the underground walls of the circular pit (pdf 2.5 Mb) crews will use to access and repair the SR 99 tunneling machine will continue through August. While this date is later than anticipated, STP reports that tunneling is still expected to resume as scheduled in March 2015.

Building a self-supporting, concrete ring that is 120 feet deep and 80 feet wide is no easy task, especially given the difficult ground conditions near South Jackson Street. STP crews have completed more than half of the underground piles and are working around-the-clock, seven days a week to complete the approximately 31 remaining piles.

There are several reasons the work is taking longer than anticipated. One factor is the addition of 11 piles to the pit’s design, bringing the total number of piles to approximately 84. Crews are also working with exceptionally large interlocking piles, which are necessary to make the pit self-supporting without tiebacks or other reinforcements. A self-supporting pit is what will allow the tunneling machine to mine through its walls, but the large piles take longer to install than standard piles.

While pile work continues, crews are making progress on other areas of the repair plan on schedule, including:

  • Shipping repair pieces: The new main bearing has arrived in Seattle and will be assembled closer to the time it’s needed, likely this fall.
  • Manufacturing repair pieces: Other repair pieces, such as the new outer seal ring, the thrust seal ring and bearing block are nearing completion. After these pieces are fabricated and inspected, Hitachi Zosen will ship them to Seattle.
  • Assembling a 300-ton crawler crane: This crane will be used to help assemble the 600-ton crawler crane. Pieces of that crane will arrive in September and assembly will begin shortly thereafter.
  • Assembling a 600-ton crawler crane: This crane will be used to assemble the modular lift tower (massive red crane) that will lift the largest pieces of the machine from the access pit. Parts of that crane will also arrive in September and assembly will begin in late September.
  • Assembling the 2,000-ton modular lift tower: Starting in late July and continuing through fall, crews will begin to stage the modular lift tower. Parts of the modular lift tower will arrive over the next several months beginning in late July.

We will continue to update you on STP’s efforts to resume tunneling by March 2015. You can watch the access pit take shape on our time-lapse camera, and view photos of recent construction on Flickr.
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Early warning – Four-day closure of SR 99 coming in late August

In late August, crews building the future north portal of the SR 99 tunnel will close SR 99/Aurora Avenue North near South Lake Union for four days. During this closure, crews will demolish and replace the section of SR 99 that crosses above Broad Street.

To minimize the need for additional closures, separate crews will complete the following work elsewhere along the SR 99 corridor during this time:

  • Utility work at Harrison Street.
  • Concrete panel replacement in SODO.
  • Expansion joint repairs on the Alaskan Way Viaduct near the Seneca Street off-ramp.
  • Ivy removal from the viaduct.

Closure information

Drivers should plan ahead for SR 99 closures from Friday night, Aug. 22 to Wednesday morning, Aug. 27. View a map of the closure.

  • From 10 p.m. Friday, Aug. 22 to 5 a.m. Monday, Aug. 25, SR 99 will be closed in both directions from the West Seattle Bridge to Valley Street.
    • Northbound SR 99 will be open from South Royal Brougham Way until midnight on Friday, Aug. 22 for exiting Seahawks traffic.
  • From 5 a.m. Monday, Aug. 25 to 5 a.m. Wednesday, Aug. 27, SR 99 will be closed in both directions from the south end of the Battery Street Tunnel to Valley Street.

Driver tips

Travelers who use SR 99 should consider the following:

  • Allow plenty of extra time and expect additional congestion on alternate routes including I-5 and surface streets.
  • Leave early or delay your trip to avoid traveling during peak commute periods in the morning and afternoon.
  • Delay or reschedule discretionary trips.
  • Consider telecommuting.
  • Choose an alternative travel mode such as King County Metro, share a ride in a car or vanpool, or walk or ride a bicycle. 

Know before you go and have a backup plan

Those who must drive are encouraged to stay engaged and check traffic conditions frequently via WSDOT’s web, mobile and phone-based traveler information systems.

  • The Seattle traffic page contains updated road information including links to traffic cameras.
  • The travel alerts website provides real-time information about blocking incidents.
  • WSDOT’s mobile app offers information for travelers on the go.
  • @wsdot_traffic provides Twitter updates about travel issues.
  • 5-1-1 offers traffic updates.
  • The What’s Happening Now page chronicles closures and issues affecting travelers.
  • Learn more about your commute and travel choices.

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Milepost 31 Speakers Series – Bertha and progress on the SR 99 Tunnel Project

Seattle Tunnel Partners, the contractor hired by WSDOT to design and build the SR 99 tunnel, is working to repair the SR 99 tunneling machine. Join us to learn more about STP’s plan to resume tunneling by the end of March 2015, and learn about the other work happening to replace the viaduct.

  • 6 – 6:30 p.m.
  • Thursday, Aug. 7
  • Milepost 31, 211 First Ave. S., Seattle
  • Admission is free

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Alaskan Way Viaduct Replacement Project Update – July 2014

BerthaContractor announces details of repair work plan for the SR 99 tunneling machine

Bertha, the SR 99 tunneling machine, has always been big. The focus now is on rebuilding Bertha and making her better, according to a new repair work plan unveiled Monday, June 16, by Seattle Tunnel Partners, our design-build contractor for the SR 99 Tunnel Project.

STP’s work plan (pdf 4.8 Mb), which is illustrated in a new animation (view on YouTube), contains four major repair and enhancement elements:

  • Replacing the damaged seal system with a more robust system
  • Replacing the main bearing
  • Installing enhanced monitoring systems
  • Adding steel to strengthen the machine and accommodate the new seal system

Other major enhancements of the work plan include:

  • Widening the openings at the center of the cutterhead
  • Improving the soil conditioning injection system
  • Installing bit- and wear-resistant steel on the cutterhead
  • Extending the length of the agitator arms in the mixing chamber

STP will provide WSDOT with additional supporting information about rebuilding the machine in the coming months, in accordance with the design-build contract, to demonstrate how the repairs will meet the contract’s performance and technical requirements, including:

  • An analysis demonstrating that the machine’s structure can withstand all loads from the surrounding ground and its own operation
  • Seal design details and background calculations
  • Design of revised conditioner injection systems and cutterhead openings
  • Updated operations plan including enhanced instrumentation and monitoring for key machine components
  • Complete testing program for all modified machine components prior to restart of mining

Bertha is currently stopped approximately 60 feet underground between South Jackson and South Main streets. As owner of the machine, STP is responsible for ensuring it functions properly at all times. STP is currently building the underground walls of a circular pit (pdf 2.5 Mb) crews will use to access and repair the machine.

 

No Milepost 31 speaker series in July

Due to the July Fourth holiday, there will be no Milepost 31 speaker series event this month. We look forward to seeing you in August.

Alaskan Way Viaduct Replacement Project Update – April 2014

Milepost 31 Events

April 19, 2014 events at Milepost 31First Thursday Speaker Series – Bertha and Progress on the SR 99 Tunnel Project

April 3, 2014
6 – 6:30 p.m.

You’ve been hearing a lot lately about our efforts to replace the State Route 99 Alaskan Way Viaduct. This is a big, complex undertaking. And as we all know, we’ve encountered some challenges. Join us this Thursday at Milepost 31 as speakers from WSDOT and our tunnel contractor, Seattle Tunnel Partners (STP), explain what’s being done to address these challenges and get Bertha, the SR 99 tunneling machine, moving again.

Speakers:

  • Matt Preedy, WSDOT’s deputy administrator for the Alaskan Way Viaduct Replacement Program
  • Chris Dixon, Seattle Tunnel Partners (STP) project manager

History Scavenger Hunt

April 19, 2014
1 – 4 p.m.

Join us at Milepost 31 for our monthly activity for kids. This month we’re hosting a scavenger hunt eggstravaganza  (pdf 371 kb) to discover Pioneer Square’s rich transportation history. Hop on down with your family and friends to explore historic icons and hidden gems in Seattle’s oldest neighborhood. Test your knowledge, check out cool new Pioneer Square locales, and enter to win a grand prize furnished by the Alliance for Pioneer Square. Pick up your scavenger hunt kit at Milepost 31 between the hours of 1 and 4 p.m.

And don’t forget you can find regular updates about Bertha on Twitter by following @BerthaDigsSR99.