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Offsite Field Trip

Experience first-hand the impact of tunneling, create meaningful dialogue and get inspired by participating in an off-site field trip and technical tour. Learn how others in the tunneling industry are improving methods, overcoming obstacles and reaching operational goals.

SR 99 Tunnel Project
(Alaskan Way Viaduct Replacement Project)

Monday, November 13, 2017

Bertha, one of the world’s largest tunneling machines – at 57.5ft (17.52m) in diameter – recently completed her drive under downtown Seattle as part of a $3.1 billion program to replace the State Route 99 Alaskan Way Viaduct, a double-deck highway that has spanned the waterfront for more than 60 years.

When the two-mile-long SR 99 Tunnel opens to traffic in 2019, crews will remove the viaduct, clearing the way for urban landscaping to create new public spaces along the waterfront and providing a greatly improved SR 99 highway corridor.

Seattle Tunneling Partners (STP JV) – a design-build consortium comprising Dragados-USA, Tutor Perini and HNTB – is constructing the tunnel on behalf of Washington State Department of Transportations (WSDOT).

Half of the viaduct is already gone, demolished and replaced at the south end of downtown, near Seattle’s stadiums. Removal of this south-end section cleared the way for Bertha, the five-story-tall, 7,000-ton Hitachi Zosen EPB machine, to start her underground journey back in 2013.

Although tunnel boring has now come to end, crews have significant work to do before the tunnel can open to traffic, including continued construction of the double-deck highway inside the tunnel and installation of the mechanical and electrical systems, such as ventilation, fire-detection and suppression, security and lighting.

This afternoon tour, hosted by STP JV and WSDOT, will take in key points of interest at the construction site and a trip through the tunnel. Tour times are 1:00pm and 3:00pm.

Includes: Tour, transportation and refreshments

Attendees are advised to bring their own work boots and safety equipment, although PPE can be provided on request.