Project Abstract

SR 520 links densely populated cities and some of the largest employers in the state. The one-and-a-half-mile long, 42 year-old SR 520 Evergreen Point Bridge is very vulnerable to windstorms and earthquakes and needs to be replaced.

SR 520 Bridge Replacement

Project History

SR 520 links densely populated cities and some of the largest employers in the state. In 2005 115,000 vehicles use the bridge every day. Fast-growing numbers of citizens depend on the SR 520 link across Lake Washington for their daily commute between home and work, to access outdoor recreational sites and shopping centers; and to attend the educational and medical institutions in the region. Congestion is typical in both directions during the AM and PM peak periods.

The one-and-a-half-mile long, 42 year-old SR 520 Evergreen Point Bridge is very vulnerable to windstorms and earthquakes and needs to be replaced. Spanning Lake Washington, the bridge has suffered through dozens of winter storms, several earthquakes and various traffic and boating accidents. Since its construction in the early 60s, these stress factors have taken their toll -- the bridge and its approach structures have aged, are becoming susceptible to earthquakes and storms and need to be replaced. Retrofit improvements have kept it safe and functional, but they won't last forever.

In 2000, the remaining useful life of the floating portion of the Evergreen Point Bridge was estimated to be 20 years, assuming no major storms or earthquakes hit the region. The risk of failure in earthquakes or storms increases every year. Therefore, the facility must be replaced before 2020.

Project Description

The bridge consists of four travel lanes, a median barrier, and narrow shoulders. The posted speed is 50 mph. The bridge could be replaced with a 4-Lane or 6-Lane facility. Both alternatives will create a seismically sound and safe new Portage Bay Bridge and Evergreen Point Floating Bridge with full shoulders, and a bike and pedestrian path through the entire project corridor. Both alternatives include pontoons large enough to support future high capacity transit (HCT). Expansion and improvements to the approach structures on the Evergreen Point Bridge, the Portage Bay Bridge, on- and off-ramps and segments of SR 520 on either end of the lake are also included in both alternatives.

During the alternative development and selection, important components that are being evaluated include cost, feasibility of construction, maintenance, safety (for all travel modes, and considerations for emergency situations), mobility, and future needs/expectations (high-capacity transit). Community acceptance is also a high priority. Specific considerations include:

• Safety - Rebuild Portage Bay and Evergreen Point bridges, reducing seismic and storm damage risks. Improve safety and reliability by providing full shoulders for disabled vehicles and emergency aid.
• Congestion Relief - Provide a dedicated HOV lane to move transit and carpools (in the 6-Lane Alternative) and provide full shoulders for disabled vehicles and emergency aid. Pontoons will be built to carry future high-capacity transit.

Both alternatives propose a substantially wider bridge than exists today. Even the 4-Lane Alternative, which replaces the current number of lanes, would be wider because it includes full shoulders and a new bicycle/pedestrian path. As a result, more land will be needed for the highway and the highway will be closer to adjacent communities. Strategies for mitigation of the impacts to the environment and communities are being developed and evaluated.

Context-Sensitive Factors

This project is being developed in partnership with Sound Transit and the Federal Highway Administration. All three agencies are involved in the project's policy- and decision-making. State funds drive 100% of the project's current work; tolls are assumed to provide some of the project's future funding.

To date, project activities have included project area tours, public meetings and open houses, jurisdictional, community and organizational briefings, committee meetings, community workshops, and neighborhood roundtables.

Public input to the SR 520 Bridge Replacement and HOV Project has been and continues to be an essential element of the project. Public involvement opportunities provide information on the project's progress and engage all community members -- ranging from residents and businesses to organizations and jurisdiction leaders.

The Project Team has conducted extensive public involvement efforts, even at the earliest stages of project development. Local stakeholders represented at workshops held in 2005-2006 include: University of Washington, Washington Park Arboretum, City of Seattle Departments of Transportation and Parks and Recreation, and local neighborhoods along the corridor on both sides of Lake Washington.

Community outreach has been an important part of the project, and will continue throughout the life of the project. The Project Team sees the Corridor Aesthetics work with the Design Advisory Group (DAG) as an important step in establishing some aesthetic guidelines that will be used by the rest of the Design Team as the project moves forward. This will include the bridge designers, architects, landscape architects, lighting designers, and others who will be preparing the final design packages for the project.

It is important that the DAG and Project Team provide the overall aesthetic direction for these specialists to consider and try to incorporate as they move in to more refined design. The community involvement efforts include the following workshops and committees:

• Local Improvement Committees
• Seattle Parks Workshops
• Community lid design workshops
• Design Advisory Group (DAG)

A discussion of each of these efforts and their progress and outcomes is included in the files titled SR 520 Parks Workshops#1.pdf, SR 520 Parks Workshops#2.pdf, and SR 520 DAG and aesthetics.pdf.

Challenges and Solutions

The existing SR 520 corridor between I-5 and Bellevue Way was built before many of the current environmental regulations were in place. As a result, many of the steps WSDOT takes to protect the environment today were not considered when it was originally built. For example:

• Water quality: Rainfall landing on the highway currently drains directly into adjacent lakes, streams, and wetlands, carrying pollutants from the highway into these water bodies.
• Noise: No sound walls were built to reduce noise from the highway.
• Habitat: SR 520 was built through sensitive habitats.
• Neighborhoods: The highway cuts through neighborhoods and creates a barrier to movement within communities.

The project will include a number of features that will benefit the environment and address the shortcomings of the original bridge and highway facilities:

• Water quality: The entire highway, including the floating bridge, will include stormwater treatment facilities to make sure stormwater draining off the highway meets the latest water quality regulations. A system of runoff treatment wetland cells will be constructed at the base of Westside bridge piers. This innovative approach to treating stormwater runoff will be implemented as a test site.
• Noise: Sound walls will be built, substantially reducing noise levels.
• Habitat: Several aspects of the new bridge will reduce the impacts to the natural habitat:
  • The new bridge will have fewer columns (250 feet apart compared to today's 100 feet between columns).
  • The unused R.H. Thomson Freeway "ramps to nowhere" near the Washington Park Arboretum will be removed.
• Neighborhoods: The benefits to local neighborhoods will include:
  • Improvements to bike and pedestrian connections along and across the highway, including a new bicycle/pedestrian path across Lake Washington, which will link Montlake and the University District with the Eastside.
  • The 6-Lane Alternative includes lids over the highway at 10th and Delmar and Montlake Boulevard in Seattle, and at Evergreen Point Road, 84th Avenue Northeast and 92nd Avenue Northeast on the Eastside to improve connections between neighborhoods currently divided by the highway.

For comments and questions about the project or to be added to the mail/email list, please fill out our contact form at http://www.wsdot.wa.gov/Projects/SR520Bridge/ContactUs.htm.

To contact the SR 520 Bridge Replacement and HOV Project office by phone, call (206) 381-6400.

See the following websites for additional information and project updates:
http://www.wsdot.wa.gov/Projects/SR520Bridge/default.htm
http://www.wsdot.wa.gov/mobility/TDM/tdm520.htm
http://www.wsdot.wa.gov/Projects/SR520Bridge/Schedule.htm

   SR 520 Parks Workshops#1.pdf

   SR 520 Parks Workshops#2.pdf

   SR520 DAG and aesthetics.pdf