Expert Panel's Briefing on Viaduct, 520 and HOV projects

Alaskan Way Viaduct & Seawall Replacement Project and SR 520 Bridge Replacement and HOV Project

Expert Review Panel June 2006

SR 520 Serves as a Critical Transportation and Transit Corridor

SR 520 is a major link between Seattle and the Eastside, with 115,000 vehicles crossing the bridge each day - more than double what the bridge was originally designed to carry
A number of Puget Sound’s largest
employers, including the University of Washington, and key business centers, are

Evergreen Point Landscaped Lid




SR 520 Bridge Replacement and HOV Project


SR 520 Bridge Replacement and HOV Project

What is our implementation
schedule and plan?

Project Schedule


Implementation Plan


• Environmental process

• Design development and approval • Right-of-way

• Construction planning


Implementation Milestones


• Preferred Alternative - Late 2006 • Record of Decision - Early 2008 • Permitting - 2008-2011

• SPCS completed - 2008-2009

• Evergreen Point Bridge construction - 2009-2015 • Corridor construction - 2010-2017


Delivery Strategy

• Early right-of-way acquisition where possible • Advance early design activities during environmental
analysis

• Replace Evergreen Point Bridge first

• Complete corridor construction as funding permits • Proactive risk management

• Keep traffic flowing during construction


Environmental Permitting

Strategies

• Early engagement of resource agencies during
environmental process

• Dedicated staff to streamline process

• Interagency agreements facilitate permit acquisition • Coordination with tribal governments and resource
agencies


Environmental Mitigation

• Sound walls along much of SR 520 in Seattle and the
Eastside

• Stormwater treatment facilities including wetlands, water
quality wet vaults and flow control systems

• Culvert replacement for fish passage • Better traffic operations improving air quality • Improved navigation channel matching I-90 • Both 4-Lane and 6-Lane Alternatives have similar natural
and built environment effects (6-Lane generally more)


Right-of-Way

• Minimize property effects using context sensitive
solutions (CSS)

• Acquire right-of-way early where possible • Disclose property effects early

• Negotiate and acquire right-of-way quickly after record of
decision


Construction Planning

• Construction assumed in three segments:
- Evergreen Point Bridge

- Seattle communities - Eastside communities

• Ongoing planning includes:
- Phasing and sequencing scenarios - Contract planning assessment(s)

- Alternative project delivery and procurement options



Special Projects Construction Site (SPCS)

• SPCS ready for SR 520 construction
by 2009

• The site will be a large plot of land
(at least 30 acres) along a waterfront

Flooding of the graving dock to

• The construction site will be used for

launch Homer Hadley Bridge

pontoons, Blair Waterway, 1981

the SR 520 Bridge pontoons and future WSDOT projects

• The goal is to build the pontoons in at
least three years (8-10 pontoons every six months) to meet the SR 520 Bridge schedule

Hood Canal Bridge pontoon construction site, Concrete Technology, 2006



Bridge Pontoons and Construction

• Up to 55 new pontoons needed for Evergreen Point Bridge • Pontoons will be sized to support future high-capacity transit (HCT) • 4-Lane: 60-foot wide pontoon

What are pontoons?

• 6-Lane: 75-foot wide pontoon

Bridge pontoons are very large hollow concrete structures that are built and outfitted at a construction site, floated to the bridge location, and then pieced together to form a floating bridge. The buoyant pontoons support the bridge structure and roadway above.


Traffic Management

During Construction

• Two lanes of traffic in each direction will be maintained
during construction.

• Night and occasional weekend closures will occur. • New Evergreen Point Bridge will be built to the north of
the existing bridge. This allows the new floating section to be moved into place and anchored without disturbing the existing bridge.

• Specific techniques and plans will be developed to
manage traffic flow and detour routes on local streets.


Cost and Construction Timeframe

Construction

4-Lane 6-Lane Cost *

$1.7 - 2.0 billion
$2.3 - 2.8 Timeframe (years) Proposed start: 2009 - 2010

New bridge open: 2013 - 2015



billion

Estimated

6-Lane with $2.3 - 3.1


construction end:

Options billion


2015 - 2017

* Cost Estimation Validation Process 2005


SR 520 is Vitally Important to the Puget Sound Region

• The SR 520 structures are vulnerable to earthquakes
and windstorms and have a limited remaining life. • Congestion will continue to increase with population
growth - 1.6 million more people by 2040. • SR 520 is a key corridor facilitating economic growth. • The project implementation plan is focused on proactive
risk management.


SR 520 Bridge Replacement and HOV Project
Funding Source
2003 State Nickel Package

2005 State Transportation Partnership Package 2005 Federal Funding

Future Electronic Tolls

Total Identified Funding Needs* Amount $52 million $500 million $1 million $700 million

$1.25 billion
$0.45 - $1.85 billion

* Includes cost of 6-Lane options