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The Alaskan Way Viaduct & Seawall Replacement Program

OrganizationDate

Institute of Transportation Engineers Quad Conference April 18, 2011

The Alaskan Way Viaduct is a 2.1-mile stretch of SR 99 running along Seattle’s waterfront.

Age, daily wear and tear, and the 2001 Nisqually earthquake have taken a toll on the structure.

Program OverviewThe Alaskan Way Viaduct and Seawall Replacement Programencompasses projects led by the Washington State Department ofTransportation, City of Seattle, King County and Port of Seattle.

Public process

Replacing the Alaskan Way Viaduct

Public process

State Project Delivery

State Projects 2010 Cost ($ in millions)

S. Holgate Street to S. King Street Viaduct Replacement (South End)

$394.8 million

S. King Street to Roy Street Viaduct Replacement (C l d b d l)

$1,960.7 million(Central – proposed bored tunnel)Central Waterfront Viaduct Removal and New Alaskan Way

$290 million

Central Waterfront Construction Mitigation $30 millionProgram Management $75 millionOther Moving Forward Projects $187.2 millionPrior Environmental Impact Statements, Right of Way and Design Costs

$163.7 million

Total $3,101.4 million

S. Holgate to S. King Viaduct ReplacementBefore construction December 2013

STAGING AREA CONTINUING CONSTRUCTION

• Roadway will be complete in 2013.• SR 99 remains open during construction.• 2011: Reduced capacity on SR 99 south of S. King Street.

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S. Holgate to S. King Viaduct Replacement Future

Demolishing the SR 99 On-ramp

Building the SR 99 Detour Driving Piles for the New SR 99 Roadway

Proposed Bored Tunnel Timeline

In 2011: • Executed design-build contract.• Publish Final Environmental Impact Statement in mid-2011 and

receive Record of Decision.• Begin construction.g

2009 2010 2011 2012 2013 2014 2015 2016

Major construction

Bored tunnel open to drivers, central viaduct demolition begins

Proposed bored tunnel timeline

Environmental process

Design-Build ContractMajor work items:

• Bored tunnel including the tunnel boring machine.

• Tunnel interior structures and systems including stacked roadway, emergency corridor, air plenum, electrical and mechanical systems.

• Cut-and-cover roadways in the north and south portal areas.

• Tunnel operations buildings at either end of tunnel which house ventilation fans and other support functions.

Design concept.

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Seattle Tunnel Partners Overview

Joint venture partners

• Dragados USA

• Tutor Perini Corporation

Main subcontractors

• Design: HNTB Corporation* and Intecsa-Inarsa

• Construction: Frank Coluccio Construction* and Mowat Construction*

* Local companies

Previous Experience

Barcelona Line 9 Metro Extension Near La Sagrada Familia

Proposed SR 99 Bored Tunnel

• Approximately two miles long.

• Tunnel designed to 2,500 year earthquake standard (in the range of a 9.0 earthquake).

• State-of-the-art safety systems.

Seattle Center

Proposed alignment

South Portal Design Concept

North Portal Design ConceptCurved Sixth Avenue

Tolling the Proposed Bored Tunnel• Up to $400 million in toll funding.

• Completed preliminary analysis and submitted 2010 cost and tolling summary report to Legislature.

• WSDOT and SDOT will convene a tolling advisory committee with participation from King County and Port of Seattle.

2010 2011 2012 2013 2014 2015 2016 2017 2018

Environmental process

Final Environmental Impact Statement and Record of Decision

Set toll rates

Proposed bored tunnel opens, tolling begins

Tolling advisory committee

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• Design-build procurement process

• Risk Identification

Contract Development and Risk Management

WSDOT used the design-build model to build the TacomaNarrows Bridge.

Design-Build Contract Development• Bored tunnel alternative contract developed with WSDOT’s most

experienced design-build contract managers, with guidance from the program’s Strategic Advisory Board (STAT), and with input from potential design-builders.

• The team, along with STAT, identified, allocated and shared i k d i t d i ti i t th t trisks and incorporated incentives into the contract.

• This process was happening simultaneously with a two step procurement process.

• Early contractor involvement allowed for the contractor input into the final RFP documents.

Managing Risk for the Bored Tunnel Contract

• Environmental• Utilities• Right-of-way• Ground conditions• Ground conditions• Coordination with other projects

Dragados – Tunnel Diameter Evolution

50

60

Dragados Tunnel Bore Diameter Evolution

Dragados – Tunnel Diameter Evolution

20

30

40

1990

1992

1994

1996

1998

2000

2002

2004

2006

2008

2010

2012

• Crews have drilled more than 100 soil borings along the alignment.

• Teams surveyed more than 300 buildings along potential tunnel alignments

Understanding Ground Conditions

alignments.

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Geological Longitudinal Profile

Geological Profile

Detail Near South Portal

g g

Engineered & Non-Engineered Fill

Recent Granular Deposits

Recent Clay & Silt

Till Deposits

Cohesionless Sand & Gravel

Cohesionless Silt & Fine Sand

Cohesive Clay & Silt

Till-Like Deposits

Peat or Wood

Tunnel Boring Machine and Mitigation Plan Tunnel boring machine type: Earth Pressure Balance

• State-of-the-art machine will include integrated monitoring systems for operations and guidance and a survey

t l tcontrol system.

• Belt measuring system would use radar to measure accurately the spoils and volume loss at the machine’s face.

– This system would help identify any voids around the tunnel that should be filled, reducing the possibility of sink holes at the surface.

• Robust settlement mitigation plan.

Construction Monitoring Area

The blue line indicates the current proposed route for the SR 99 bored tunnel. The areas shaded in red indicate where monitoring would take place during bored tunnel construction.

Settlement Monitoring

• WSDOT developed settlement criteria for contractor.

• Buildings would be equipped ith l ti it iwith real-time monitoring

devices.

• Monitoring buildings and working with property owners would help to prevent and minimize settlement-related damage. Installation of vibration and tilt instruments in the

basement of a building.

Protecting Buildings During Construction

• Soil strengthening is done to protect above ground structures from potential settlement.

• Crews inject grout to compensate for lost ground.

• Soil strengthening would be required in addition to structural rehabilitation.

Next Steps• Continue major bridge and road

construction for south end project.

• Publish the Final Environmental Impact Statement for the central waterfront viaduct replacement in summer 2011.

• Anticipate Record of Decision (ROD) to be issued in summer 2011.

• Issue Phase II Notice to Proceed, and begin construction of the proposed bored tunnel after the ROD.

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Alaskan Way Viaduct and Seawall Replacement Program

Website: www.alaskanwayviaduct.org

E-mail:viaduct@wsdot wa govviaduct@wsdot.wa.gov

Hotline:1-888-AWV-LINE

Back Pocket

Program History

Nisqually earthquake damages viaduct

2001 2004Draft EIS analyzes five alternatives

2006Supplemental Draft EIS analyzes two alternatives

2007No/no advisory vote leads to new approach

2009Governor signs bill endorsing bored tunnel alternative

2011

Public process

Hired SR 99 bored tunnel design-build contractor.

Building Condition – Structural Issues

• Three structural rehabilitation options:

• Option A: Steel bracing inside east, south and west walls ($29 million).

• Option B: Steel trussing inside the building cladding. Framing would be stiffened by steel bracing ($36 million).

• Option C: Exterior concrete walls stiffened by reinforced shotcrete wall

WSDOT Studied Four Options

p yinside the building cladding ($35 million).

• Building demolition: Demolish prior to start of tunneling ($2.5 million plus mitigation).

Option A

Western Building Recommendations

• In March WSDOT announced a proposal that would:

• Preserve the 619 Western Building.Add ti• Address preservation concerns and keeps the proposed tunnel project on schedule.

• Return the building to its owner after construction in a functional and structural condition that is similar to today.

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Proposal Features – Tunnel BoringTunnel boring machine type: Earth Pressure Balance

• State-of-the-art machine will include integrated monitoring systems for operations and guidance and a survey

t l tcontrol system.

• Belt measuring system would use radar to measure accurately the spoils and volume loss at the machine’s face.

– This system would help identify any voids around the tunnel that should be filled, reducing the possibility of sink holes at the surface.

• Robust settlement mitigation plan.

Tunneling technology• Tunneling technology is rapidly

advancing, with tunnel boring machines as large as 62 feet in diameter on order.

• Successful tunnel boring machine projects:

Seattle

p ojec s

– Shanghai Yangtze River (China): 50.6-foot diameter

– Fourth Elbe River Tunnel (Germany): 46.6-foot diameter

– Lefortovo Tunnel (Russia): 46.6-foot diameter

– Madrid M30 (Spain): 49.9-foot diameter

Realigned SR 99 On- and Off-Ramps

SR 99 southbound off‐ramp

SR 99 northbound on‐rampFirst Avenue S.

Viaduct and Seawall Vulnerabilities

Alaskan Way S. Northbound DetourBefore construction

Project Delivery - Proposed Bored Tunnel

North portal areaTwo design-bid-build contracts for:1) Connections to SR 99 and city street grid2) Surface street improvements

South portal areaOne design-bid-build contract for surface street improvements and connections to SR 99 and city street grid.

Design-build contract / RFPIncludes boring machine, tunnel boring, tunnel roadway and systems, operations buildings, cut-and-cover sections of tunnel and settlement mitigation.

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South Portal Design Concept Previous South Portal Design Concept

Holgate to King in 2014Southbound First Avenue/Cherry

Holgate to King Current Construction

Coast Guard

BNSF/SIG RailyardCOLORADO AVENUE S

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2

Construction area

Scheduled for full closure

Partial closures/lane restrictions

Revised bicycle/pedestrian path

Port of Seattle‘sTerminal 46

Safeco Field

Qwest Field

FIRST AVENUE S.

ALASKAN WAY S.

S KING

STREET

S. RO

YAL BRO

UG

HAM

WAY

UTAH AVENUE S.

COLORADO AVENUE S.

99

1

3

2

4

5

6

3

S. ATLANTIC

STREET

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New road opening in mid-February

Section of Alaskan Way S. closing permanently in spring 2011

Building new ramp connection Begin building new SR 99 bridge

Begin demolishing and reconfiguring on-ramp in mid-February

New temporary location of SR 99 on- and off-ramps beginning in winter / spring 2011

Cross Section at Washington Street

Bored Tunnel Underground VideoBored Tunnel Underground Video

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Bored Tunnel Drive-Through VideoBored Tunnel Drive Through Video

Proposal Features – Schedule and Roadway

RFP Requirement Proposal BenefitSubstantial

completion byNov. 1, 2016.

Open tunnel by December 2015.

Allows remaining viaduct to be

demolished sooner.

RFP Requirement Proposal Benefit30-foot roadway width and 15-foot vertical clearance.

32-foot-wide roadway and six

additional inches of vertical clearance.

Wider 8-foot safety shoulder along

roadway.

Tunnel Boring Machine Animation Seattle’s Downtown Waterfront

Today Future

Keeping People and Goods Moving During Construction

• Roadway improvements: SR 519 and Spokane Street Viaduct Fourth Avenue off-ramp.

• Transit investments: Added bus service and strategies to encourage transit, carpools and vanpools.

• System reliability: Variable speed and travel time signs on I-5, and real-time traffic information on SR 99 and other routes to downtown.

Increased service from West Seattle. Driver information signs on I-5.

Construction Coordination Goals

• Agencies continue to work together.

• Identify potential conflicts.

• Coordinate work to minimize

• Maintain public trust.

• Keep traffic moving.

• Maintain business and resident access.

impacts to the public.

• No surprises. • Build upon past experience.

• Establish inter-agency web portal.

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• Construction coordination and planning for 6-8 years out

• Include special events

Long-Term Construction Coordination

• Quarterly updates of project schedules

• City/State have developed a GIS-based tool to help track and analyze data both geographically and across time

Short-Term Construction Coordination

• Weekly coordination meetings: WSDOT, SDOT, Seattle City Light and others

• Working together daily to spot and resolve conflicts

• Information feeds communication tools

Cross Section at Union Street Sample Risk Issues• Soils:

• Mitigated: Boring program and contractual requirements.

• Assigned/shared risk: Expected interventions and contingency funds.

• Incentives: Contractor receives 75 percent of remaining• Incentives: Contractor receives 75 percent of remaining contingency fund.

• Deformation:

• Mitigated: Analysis of soils and buildings, discussions with property owners and contractual requirements.

• Assigned/shared risk: Assignment for expected risk and contingency funds.

• Incentives: Contractor receives 75 percent of remaining contingency fund.