tunnelling-journal (1)
tunnelling-journal (1)
  • Home
  • Print
    • Subscribe
    • Tunnelling Journal
    • Breakthrough
    • ITA Activity Report
    • A&NZ Journal
    • WTC Preview
    • Media Kit
  • Digital
    • Newsletter
    • E-Shots
    • TJ Digital edition
    • Products Page
    • Media Kit
  • Conferences
    • BTS Conference and Exhibition
    • Cutting Edge 2022
  • Buyer’s Guide
  • Events Diary
  • Jobs
  • About Us
  • Contact Us
  • Podcast

Home > STP releases Bertha's re-start schedule

STP releases Bertha's re-start schedule

Tris Thomas

Written by Tris Thomas on 22/04/2014 in News

Tagged: underground

Seattle Tunnel Partners (STP), the Washington State Department of Transport’s (WSDOT) design-build contractor on Seattle’s SR-99 Alaskan Way Viaduct replacement tunnel project, has released a new schedule that shows the SR 99 tunnelling machine will resume digging by the end of March 2015.

Construction will begin late next month on the shaft STP will use to access and repair damage to the machine, which stopped tunnelling in December. Building the access shaft is the first of several steps STP has laid out to resume tunnelling:

  • Late May: Begin building the access shaft’s underground walls.
  • Late July through September: Excavate the shaft.
  • October: Remove the machine’s cutterhead and begin repairing damage to the seal system and main bearing.
  • February 2015: Test machine to ensure it is ready to tunnel beneath downtown.
  • Late March 2015: Resume tunnelling.

These construction activities will be addressed in accordance with the SR 99 tunnel contract. The updated construction timeline delays tunnel boring by up to 16 months, but STP hopes to recover as much as four months of schedule to meet the November 2016 tunnel opening date WSDOT established in its 2010 request for proposals. STP had proposed opening the tunnel in late 2015, 11 months earlier than the original requirement.

STP has informed WSDOT that crews will replace the machine’s main bearing and install a more robust seal system, which could include strengthening the seals, installing redundant systems, and adding monitoring equipment. Additional details will be included in a plan to be submitted to WSDOT for review by June 16.

The repair schedule will include additional time to accommodate potential improvements to the machine that STP or the machine’s manufacturer, Hitachi Zosen Corp., might choose to make after the cutterhead is removed and crews are able to perform a full inspection. WSDOT will work with its strategic technical advisory team, made up of international and national tunnelling experts, as well as consultants, to review the plan.

Although disappointed by this delay, WSDOT believes the schedule is moving in the right direction, saying in a statement “We’re also focused on the bigger picture, which includes more than $750 million worth of work at the tunnel portals and elsewhere along the SR 99 corridor. That construction is not affected by the tunnelling stoppage and continues full speed ahead.”

West of Seattle’s stadiums, crews are building the future connection between the tunnel and the new section of SR 99 that was completed in 2012 after the viaduct’s southern mile was demolished. Crews are also making progress on the south portal operations building, which will house lighting, ventilation, emergency systems and other vital components needed to operate the tunnel.

Meanwhile, at the tunnel’s future north portal, crews are building the connection between the tunnel and Aurora Avenue North, the north portal operations building and the 80-foot-deep pit where the tunnelling machine will emerge at the end of its journey beneath downtown.

Work is also ongoing in Frederickson, Wash., where crews have manufactured 72 percent of the concrete segments.

Comments:

Leave a Reply Cancel reply

Your email address will not be published. Required fields are marked *

Search

Digital Edition

More Like This

25/03/2022

Robbins Single Shield completes Canada’s Largest Outfall

Robbins Single Shield completes Canada’s Largest Outfall

On March 3, 2022, a 7.95m (26.1 ft) diameter Robbins Single Shield TBM completed a record-setting run below Lake Ontario….

01/04/2022

Robbins Main Beam Finishes Challenging China Drive

Robbins Main Beam Finishes Challenging China Drive

The breakthrough in the first quarter of 2022 of an 8m diameter Robbins Main Beam TBM at China’s Yin Han…

19/04/2022

Ayesa wins Santiago Metro Line 7 contract

Ayesa wins Santiago Metro Line 7 contract

The Santiago Metro in Chile has awarded Ayesa, a global provider of technology and engineering services, an €11M, 66-month contract…

  • Contact Us
  • Media Kit
  • Magazine Archive

Newsletter

The latest from the Tunneling Journal direct to your inbox.

Social



Enquiries

TGS Media Ltd
The Old Library
Webster House
Dudley Road
Tunbridge Wells
TN1 1LE
United Kingdom

© Tunnelling Journal. All Rights Reserved. Privacy Policy / Terms & Conditions. Admin

We use cookies to ensure that we give you the best experience on our website. If you continue to use this site we will assume that you are happy with it.OkRead more