Alaskan Way selects construction management Apr 2011
TunnelTalk reporting
Hatch Mott MacDonald is selected to provide construction management services for the Alaskan Way viaduct replacement project in Seattle.
Proposed bored tunnel replacement of the earthquake-damaged viaduct

Proposed bored tunnel replacement of the earthquake-damaged viaduct

Under a contract valued at about $11 million, the firm will undertake a five-year Construction Management role for the entire project including oversight of the $1.35 billion design-build contract awarded in January to Seattle Tunnel Partners (STP), a joint venture between Dragados and Tutor Perini.
Appointment of Hatch Mott MacDonald to Construction Management is in addition, and separate, to its current and continuing role as Program Management and Advisory Consultant (PMAC) to WSDOT, the Washington State Department of Transportation and owner of the project.
As lead of the management team, Hatch Mott MacDonald is joined by several specialist sub-consultants including Construction Management Services Company, LLC, EPC Consultants, Inc.; Dr Donald Lamont of Hyperbaric Tunnel Safety, Ltd; Maidl Tunnelconsultants GmbH & Co. of Germany; Paladin Professional Consultants, LLC; Bob Essler of RD Geotech, Ltd.; and Richard Lewis of YL Associates, Ltd as adviser on TBM design and operations.
While different oppositions groups in Seattle continue to try and stop construction of the project, STP has started work on design of the world's largest TBM bored tunnel to date. At more than 17.6m in diameter (58ft high and wide), STP has selected EPB technology to comply with the specified use of a closed face, pressurized TBM system through the waterbearing glacial geology beneath Seattle and an order will be placed with one of a short list of qualified manufacturers. The machine will excavate the 2.7km long (1.7 miles) double-deck four-lane highway tunnel, with an emergency lane in each direction and space to accommodate all types of highway traffic, including 16-wheeler trucks.
New south section of SR 99 allows first demolition of the viaduct

New south section of SR 99 allows first demolition of the viaduct

In the meantime, heavy construction work has started on the project with of a new section of highway and the demolition of the southern half of the viaduct between S. Holgate Street to S. King Street. Under a $114.5 million contract awarded to Skanska USA Civil in May last year, more than a mile of the aging and damaged viaduct is being replaced with a new side-by-side at grade roadway that is build to current earthquake standards and has wider lanes than those on the viaduct. While this work is part of the overall viaduct replacement project, the new section of the SR 99 highway to the south is separate and can stand-alone from the bored tunnel replacement of the central waterfront section.
A four-lane construction detour will connect back onto the viaduct just south of S. King Street until the central waterfront section replacement is completed. Work has progressed well on the Skanska contract. A new on-and-off ramp to the elevated viaduct will open later this year to provide a detour around the 1 mile section of the highway to allow for construction of the new at-grade highway and the eventual demolition of that section of the viaduct in spring/summer next year (2012). A notice to proceed with excavation of the bored tunnel as the replacement of the central waterfront section of the viaduct is awaited until the Federal environmental impact statement (EIS) is cleared. The EIS is currently with the Federal Government and a Record of Decision to indicate its approval is expected in August this year. Once that is received it will be full steam ahead for construction of the world’s largest bored tunnel highway.
Alaskan Way bored tunnel project awarded - TunnelTalk, January 2011
Alaskan Way mega-project procurement - TunnelTalk, October 2010

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