Alaskan Way Viaduct
North Portal and Freight Connections



Port of Seattle Commission
March 10, 2009

Bored-Tunnel Hybrid
Current Status
SB 5768
Approved by State Senate March 4 by vote of 43-6
State commitment of $2.4 billion for cost of tunnel,
additional $400 million through tolling
Tunnel features 4 lanes under First Avenue, extending
from sports stadiums to approximately Harrison Street
near Aurora Ave. N
State responsible for tunnel and portals; City of Seattle
responsible for utility relocation, seawall and waterfront
improvements; King County responsible for transit

Port of Seattle relies on an
efficient transportation system
The choice for the replacement of
the Alaskan Way Viaduct should
achieve the best balance of:
job retention and creation
sustainable regional
economic vitality
environmental benefits
1. Maximize jobs and economic
benefits in weighing total, life-cycle
costs
2. Ensure efficient access to the
working waterfront for a growing
economy
3. Enhance the waterfront
environment for people & goods
4. Replace capacity for long-term
regional growth
5. Support seawall improvements

Priority questions
Designs for the other essential street network
connections
Efficient surface connection for NW Seattle, freight
mobility, Terminal 91 access
Connectivity between north and south industrial areas
Traffic flow on Alaskan Way surface street
Portal connections to the street network

Port of Seattle Commissioners
March 10, 2009

Letter of Agreement
On Jan. 13, 2009, Governor Gregoire, King County Executive Sims and
Mayor Nickels signed a letter of agreement signifying their support of the
bored tunnel hybrid alternative.

Bored Tunnel
A bored tunnel under First Avenue is the new SR 99. Some features
include:
Least traffic and business disruptions
during construction.
Two lanes of traffic, with shoulders,
in each direction.
Approximately two miles long.
Between 30 and 200 feet
underground.

Bored Tunnel Hybrid
Improves public safety.
Encourages job creation and health of the regional economy.
Maintains movement of people and goods for trips to and through
downtown.
Improves pedestrian access.
Improves transit frequency and reliability.
Minimizes construction and traffic impacts.
Improves key east/west city street connections.
Reconnects downtown and Elliott Bay, creating a world-class waterfront.

Bored Tunnel Hybrid Alternative

Mobility

How Northwest Seattle will access the Bored Tunnel



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Auto" Avenue North Routes

Westbke and Dene: Routes

How Northwest Seattle will get to and through
downtown using the new Alaskan Way





New bridge over
railroad tra161 miles
subway lines.
*Boston Big Dig tunnels included cut-and-cover, immersed
2. A signature cable-stayed bridge over the Charles           tubes, jacked tunnel and other special tunneling methods.
River, cut-and-cover through South Boston.
3. Two sets of immersed tubes under the harbor to the     SR 99 Bored Tunnel
airport and the complex interchange with very poor      Project will run 30-200 feet underground
geotechnical conditions.                         minimizing traffic disruption and impacts to the
Project was disruptive and required extensive     waterfront and downtown
traffic management and mitigation.           WSDOT uses the CEVP process on all state
The initial project cost number did not include     projects over $100M to ensure costs are complete,
added scope, mitigation and environmental      reasonable, defendable and appropriately
requirements, inflation and appropriate         represent risk and uncertainties.
allowance for risk and escalation.             WSDOT is a strong owner in policy, management
and technical capability and Governor Gregoire is
The Central Artery/Tunnel did not have a
project authority
strong agency management or consistent
leadership throughout the course of the        WSDOT will maintain this strength over the life of
project.                                 the project, assisted by eminent private-sector
engineers and contractors
As a result, the project was delivered grossly
over budget and years behind schedule. - Accountable to the public, Governor and
Legislature

Tunneling Technology
Tunneling technology is rapidly
advancing, with tunnel boring
machines as large as 62 feet in
diameter on order.
Seattle
Successful tunnel boring machine
projects:
Sound Transit Beacon Hill: 21
feet in diameter
Hamburg and Moscow: 46.6
feet in diameter
Madrid: 50 feet in diameter
Shanghai: 50.6 feet in
diameter

Tunneling in Seattle Soils
Numerous tunnel machines, including several in Seattle, have successfully
excavated ground conditions similar to those anticipated. Over 150 tunnels
have been constructed in Seattle since 1890, mostly in glacial soils.
Examples include:
Sound Transit Beacon Hill:
Glacial sand, silt, clay and till up to 160-ft depth.
Soils were similar to the hard/dense soils along most of
proposed alignment.
Denny Way CSO:
Glacial sand, silt, clay and till up to 160-ft depth.
Soils were similar to hard/dense soils along most of
proposed alignment.

SR 99 Bored Tunnel Cost
Risk-based estimating nationally recognized as a best practice
Cost
for mega-projects                             (Millions)
Construction Estimate (bored tunnel only)                          $944
Construction Management and Administration                      $118
Preliminary and Final Design                                  $118
Contingency                                        $150
Risk                                               $268
Escalation (per Global Insight)                                   $166
Right-of-Way Costs                                      $149
TOTAL                                  $1,913


Successful Delivery of Bored Tunnel Projects
Examples of Tunnel Excavation in Urban Areas                  Elbe Tunnel Slurry Machine
1.  4th Elbe River, Hamburg: Successfully excavated 1.6
miles at 46.6-ft-diameter.
2.  Lefortovo Tunnel, Moscow: Rebuilt Elbe TBM successfully
excavated 2 bores each 1.4 miles long at 46.6-ft-diameter.
Same machine refurbished for another 2 tunnels in
Moscow.
3.  Madrid M30 EPB: Successfully excavated 2 bores each
1.3 miles long at 50-ft-diameter by 2 closed-face TBMs
built by different manufacturers. M30 diameter was about
10 ft larger than previous TBMs (~50% greater face area).
Madrid Calle M30
4.  Shanghai Yangtze River Mixshield: Successfully
excavated 2 bores each 4.6 miles long at 50.6-ft-diameter.
This TBM is the current record holder for diameter. Tunnel
completed about a year ahead of original schedule.
Pending Record Holder
Moscow Road/Rail Tunnel: A 62-ft-diameter Mixshield has
been ordered. This diameter is 11-ft larger than Shanghai
TBM, the current record holder.
Seven tunnel boring machines will be used in
the Madrid Calle 30 project

Metro's Funding Gap