SR 520 Construction Corner

The go-to source for information on SR 520 construction

Portage Bay Bridge and Roanoke Lid Project

The SR 520 Portage Bay Bridge and Roanoke Lid Project will replace the aging Portage Bay Bridge with two parallel bridges for eastbound and westbound traffic. The old, 1960s-era bridge has hollow support columns that could collapse in a strong earthquake. The new bridges, built to modern seismic code, will have solid columns. The new bridges will improve travel for busses and carpools and extend the SR 520 Trail from Montlake to I-5. In addition, the project will build a “lid” over SR 520 that reconnects Seattle’s Roanoke Park and north Capitol Hill neighborhoods. The lid will include open green space with trail connections and viewpoints of the city and Portage Bay.

portage bay birdge at sunset


What is the timeline for construction of the new Portage Bay Bridge & Roanoke Lid Project?

WSDOT plans to advertise a Request for Qualifications (RFQ) from contractors in late 2022. This project will be a design-build contract, which means the contractor completes the final design and constructs the project. Following the release of the RFQ, design-build teams submit their qualifications. WSDOT evaluates the submittals and develops a shortlist, targeting three qualified bidders. A Request for Proposals (RFP) will be released to the shortlisted bidders in early 2023. WSDOT plans to award the contract in summer 2023. Construction is expected to begin as early as 2024 and last approximately six years.

Property Acquisition

Is WSDOT acquiring properties to build the new Portage Bay Bridge & Roanoke Lid?

In 2012, WSDOT acquired properties on the west side of Portage Bay, just south of the bridge. These properties will be used by our selected contractor for construction purposes. There are several remaining pieces of property that WSDOT needs to acquire to build the project, and WSDOT is actively coordinating with these property owners.

What is a "subterranean easement" and why does WSDOT need it?

An easement is a signed document that grants legal permission to install equipment or perform work on someone else’s property. A subterranean easement grants this type of permission beneath the ground surface of a property. WSDOT will need to acquire subterranean easements from property owners close to the Portage Bay project area to construct the Roanoke Lid, provide anchoring for new walls that protect against landslides, and build new paths and trail connections. Some of these easements will be temporary and only needed for the duration of construction while others will be permanent.

What is eminent domain and condemnation?

Eminent domain is the power of the government to acquire property or property rights needed for a public use upon payment of "just compensation." An independent appraiser will conduct a fair market appraisal to determine the amount of just compensation. Condemnation is a step in the eminent domain process. It allows the courts to give a fair and impartial determination of compensation and damages and to resolve any differences between the parties.

Will WSDOT use eminent domain for property acquisitions or easements?

When WSDOT identifies properties or easements that it needs for construction projects, it works with an independent appraiser to determine the market value of the property (or temporary property rights). The appraiser assesses the value of the property rights and provides a fair market appraisal of just compensation. Ideally, WSDOT will work together with the property owner to agree upon a negotiated settlement. If a settlement cannot be reached, WSDOT will then begin the eminent domain process. In that process, the court ultimately decides the amount of just compensation.

Boyer Stairs

Why is WSDOT removing the Boyer stair connection, and will it be replaced?

The current stair connection between Boyer Avenue East and Delmar Drive East will need to be removed to make room for the new, wider Portage Bay Bridge. WSDOT and SDOT have been coordinating on solutions to replace the connection over the past several years.

WSDOT analyzed several stair replacement options that would comply with the Americans with Disabilities Act (ADA). However, these options were ultimately not possible because of landslide risk, impacts to the neighborhood, and required property acquisition. Therefore, in collaboration with SDOT, WSDOT is moving forward with a plan to replace the stairs and provide alternative connection improvements through the neighborhood via 11th Avenue East, East Edgar Street, and Boyer Avenue East.

The plans are still in development for the alternative connection and will include improvements such as replacing sections of sidewalks, building a new section of sidewalk along 11th Avenue East at the East Edgar Street intersection, installing curb ramps, and removing vegetation blocking sidewalks. The alternative route improvements will likely be implemented before we remove the existing stairs and the replacement stairs will be constructed once the new bridge is complete.


Will there be noise during the day and night, and will there be limits on the amount of noise?

Construction on the new Portage Bay Bridge and Roanoke Lid will happen during the day and night. Night work is necessary for construction activities that impact traffic. It is often the only feasible time to close lanes or ramps.

WSDOT is committed to following noise regulations and using best practices to reduce noise. Daytime construction activities will be done within the daytime noise limits set by the city of Seattle. However, because nighttime work will also be needed to complete the project, WSDOT must apply for a Major Public Project Construction Noise Variance (MPPCNV) through the city. This will set the limit for the allowable level of noise at night.

Why will construction be done at night?

WSDOT is committed to completing the project with as little disruption to our neighbors as possible while finding a balance with the traveling public. While we aim to finish construction during the daytime, there are times when activities must be done overnight for the safety of the public as well as crews, or to avoid causing major traffic congestion and delays.

In some cases, round-the-clock work can shorten a period of higher disruption and lower the impacts to neighbors and region. When work does happen at night, WSDOT will require contractors to use the quietest methods and equipment as possible, monitor noise levels with electronic noise meters, and offer hotel stays to those likely to be most affected. To the extent it keeps people safe, reduces periods of disruption, and shortens the duration of construction, limited use of night work can minimize overall impacts and costs to taxpayers, people commuting, and nearby neighbors.

What is a Major Public Project Construction Noise Variance (MPPCNV)?

The city of Seattle defines a "major public project" as a project for a public facility that has a substantial effect on public safety, health and welfare, and the provision of public services, including transportation. The MPPCNV is a noise variance that sets limits for the allowable nighttime noise for a construction project. The process is designed specifically for major public construction projects and is administered by the Seattle Department of Construction and Inspections. This variance will apply only to the Portage Bay Bridge & Roanoke Lid Project.

WSDOT hosted an online public meeting regarding its draft MPPCNV application in January 2022. You can find the MPPCNV presentation (PDF 27MB) online. We updated the MPPCNV based on public feedback and submitted the final application to the Seattle Department of Construction and Inspections (SDCI) in May 2022. SDCI held a public hearing on August 14, and we are awaiting a final decision.

What is a temporary noise variance (TNV)?

A temporary noise variance is different than the MPPCNV. A temporary noise variance may also be granted by the city of Seattle, but it applies only for short periods of time. An MPPCNV typically lasts for the duration of a construction project. The temporary variances are granted when construction activities—say, over a weekend— may exceed the MPPCNV noise levels but are necessary to complete the project.

What is WSDOT doing to help homeowners who live near noisy construction?

In 2018, the Washington State Legislature included grant funding to help homeowners who are affected by construction on the Montlake Project. Residents near noisy construction can use the funding for noise-reducing items, such as window inserts, noise-dampening drapes, headphones, or air conditioning units. While WSDOT has authorization to extend the program for the remaining Rest of the West projects, including the Portage Bay Bridge & Roanoke Lid Project, WSDOT will need to go back to the Legislature for additional funding. The exact dollar amount per residence depends on legislative funding and the total number of homes affected.

How does WSDOT help homeowners when there are high levels of nighttime noise?

In cases where there may be loud nighttime noise, WSDOT and our contractor will offer short-term hotel accommodations to nearby residents. The contractors will handle hotel bookings and costs while residents will be responsible for transportation to the hotel. Hotels generally will be located close to the neighborhood.

Boating Access

Will boat access to the south Portage Bay shoreline be cut off during construction of the Portage Bay Bridge?

WSDOT plans to maintain a navigation channel during construction of the Portage Bay Bridge. The channel will provide approximately 10 feet of vertical clearance under the temporary work bridge throughout construction and allow small boat access to south Portage Bay. This clearance will be provided when the lake is at its highest level in the summer and will exceed 10 feet when the lake levels drop in the winter. There will be some temporary closures of the navigational channel for safety reasons.


Is WSDOT going to dredge and remove the sediment in Portage Bay?

WSDOT will not be dredging or excavating large areas of the bottom of the bay to avoid disturbing the sediment. WSDOT will disturb the smallest area possible within Portage Bay and will test and dispose of any contaminated material.

Sediment in the bay comes from many sources around the shoreline. Seattle Public Utilities maps show approximately 20 stormwater and combined-sewer outfalls that discharge into Portage Bay. Stormwater runoff from the Portage Bay Bridge represents a relatively small percentage of the basin’s overall stormwater and sediment discharge. Runoff from city streets, public parkland, and commercial and residential properties surrounding the bay are significant contributors to sediment in the bay.

The good news is that the new Portage Bay Bridge, like the rest of the reconstructed SR 520 corridor, will capture and treat the highway’s runoff rather than let it flow directly into local waterways.

Construction Impacts

What methods does WSDOT use to protect homes from the potential effects of construction?

WSDOT offers pre- and post-construction inspections to affected historic properties and properties located close to construction areas. These inspections are done by the design-build contractor before construction begins to capture a dwelling’s existing conditions and create a baseline for vibration. WSDOT will reach out to property owners within the construction area for pre-construction inspections in advance of construction.

How will community concerns about construction be heard?

WSDOT values feedback and open communication with the public. One of the ways WSDOT works with the community to help address construction effects is through a Community Construction Management Plan (CCMP). The CCMP outlines how the public can provide ongoing input into construction decisions to help avoid or reduce the effects of construction activities on the neighborhood. Once the Portage Bay Bridge & Roanoke Lid contractor is selected, the contractor will finalize the CCMP before construction starts. You can review the Portage Bay Bridge & Roanoke Lid CCMP and visit our online open house to submit a public comment.

Additionally, WSDOT plans to require the contractor to hold regular meetings with the neighborhood as construction progresses. There will be multiple opportunities for the community to provide feedback for construction staging. To learn more about the CCMP process and see examples of previous plans, visit the SR 520 Construction Corner.

What happens if my home is damaged due to construction activities?

WSDOT has created a vibration damage fund for construction-related damages under $15,000. This streamlines the insurance process and allows WSDOT to directly reimburse homeowners. If building damages over $15,000 occur due to construction activities, WSDOT will provide reimbursement through the tort claim process, which is a process that determines liability and compensates for damages and losses accordingly. Participation in preconstruction inspections will help speed up the tort claim process and help WSDOT confirm any potential damages caused from construction.

Traffic and Parking

What is WSDOT doing about construction-related traffic effects?

Like on previous SR 520 projects, WSDOT has been collaborating with the city of Seattle and the public to develop a Neighborhood Traffic Management Plan (NTMP). The purpose of this plan is to proactively identify solutions for community traffic concerns before construction starts.

WSDOT and SDOT collected community feedback via a neighborhood traffic survey and held a joint public meeting on August 4, 2022 to discuss the draft NTMP report. You can find the PowerPoint slides to the presentation online. You can read the draft plan and submit comments through Aug. 26. Please note: the scope of the NTMP has traditionally focused on local traffic improvements and not staging and haul routes. The latter two issues—staging and haul routes—are covered more in depth in our Community Construction Management Plan (CCMP). We invite your input on local traffic measures outlined in the NTMP and staging and haul routes outlined in the CCMP.

What commitments has WSDOT made to reducing the effects of truck traffic on designated haul routes?

The SR 520 program area includes a number of properties with designated historic status, as defined through Section 106 of the federal National Historic Preservation Act. This law requires WSDOT to work with affected stakeholders to collaboratively develop agreements to reduce a project’s effects on historic properties. WSDOT made commitments related to truck traffic and haul routes in its Section 106 agreements. Some of these include ensuring that the roadway surfaces of the haul routes are repaired before construction and developing measures to minimize impacts to street elements, like planters and traffic circles, from construction/hauling traffic. Read WSDOT’s Section 106 agreement and WSDOT’s draft Community Construction Management Plan (CCMP) to share your feedback or concerns.

Will there be any effects on bus service in the area due to project construction?

There may be some temporary bus service disruptions or detours caused by the project construction. WSDOT will coordinate with King County Metro and the city of Seattle on any potential service changes and will provide advance notification if service changes occur.

How will WSDOT address encampments and people who are experiencing homelessness during project construction?

WSDOT has heard community concerns regarding encampments in the vicinity of SR 520. Once construction activities begin in the Portage Bay area, people experiencing homelessness within the construction area will be relocated due to safety concerns. WSDOT and our selected contractor will work with the city of Seattle and other local partners to help connect people with shelter and other services.

We recognize homelessness is a complex issue. The COVID-19 pandemic has made this issue even more complex as WSDOT prioritizes the safety and health of our staff and contractors, neighboring residents, and people experiencing homelessness. We will work to keep the community informed as WSDOT prepares for construction and as local policy surrounding homelessness, health, and public safety continues to evolve.


Why is WSDOT applying for a shoreline permit?

WSDOT applied for a shoreline permit for the Portage Bay Bridge and Roanoke Lid Project because construction activities are required within the Portage Bay shoreline area. After submitting our permit application in August 2021, the Seattle Department of Construction and Inspections hosted a 30-day public comment period. SDCI received 87 public comments. You can read the public comments and WSDOT's response to comment themes at the Seattle Services Portal.

WSDOT previously applied for and received Seattle shoreline permits for the entire SR 520 corridor in Seattle in 2012. Due to the amount of time that has passed, the number of design refinements since the original shoreline permit was issued, and significant changes in the city code, the city requested that WSDOT apply for a new permit for the Portage Bay Bridge and Roanoke Lid Project.

What is WSDOT doing to mitigate environmental impacts from the SR 520 Program?

WSDOT has done extensive work with communities and regulatory agencies to mitigate the environmental and recreational effects of our projects by restoring wetlands, improving creeks and ponds, building and enhancing trails, rehabilitating shorelines and restoring fish-migration corridors. We have compiled a full list of SR 520 mitigation and enhancement projects on our program website.

WSDOT has also contributed to the King County Mitigation Reserves Program, which allows participants to pool financial resources for larger restoration projects with greater environmental benefits. WSDOT is contributing to the county's program to mitigate a portion of the SR 520 program's impacts to wetlands.

How is WSDOT improving sustainability on SR 520 projects?

WSDOT prioritizes design approaches that minimize steel and concrete requirements. For example, the Portage Bay Bridge's design substantially reduced the number of in-water columns and the amount of concrete needed to build them. WSDOT also includes sustainability provisions to ensure that our selected contractor reduces emissions with sustainable construction practices, such as reducing, reusing, and recycling construction materials.

Additionally, WSDOT evaluated greenhouse gas emissions in the 2011 Final Environmental Impact Statement. A detailed analysis is available in the Energy Discipline Report Addendum and Errata. The selected conceptual design, called the preferred alternative, will reduce congestion, and increase transit use leading to an estimated 5% to 10% reduction in vehicle miles traveled on SR 520 and a nearly 10% reduction in vehicles' greenhouse gas emissions when compared to a no-build option with no highway improvements.

Frontline Neighbors

What’s a frontline neighbor?

WSDOT defines a frontline neighbor as a neighbor who lives close to the project construction area and will likely be affected by construction impacts such as noise, vibration, air quality, and lighting. Because of the project area’s unique geography, and the fact that noise travels across the Portage Bay, the Portage Bay Bridge & Roanoke Lid Project will include a larger span of frontline neighbors than previous SR 520 projects.

How is WSDOT engaging frontline neighbors on the Portage Bay Bridge & Roanoke Lid Project?

This April, WSDOT hosted two online meetings for neighbors whose homes are closest to the project construction area (view the slides and view the Q&A) so they could know what to expect about the project before construction begins in 2024.

Beginning in June, WSDOT will launch an online open house for frontline neighbors in the broader Portage Bay, north Capitol Hill, University District, and Montlake neighborhoods. The purpose of the online open house will be to share information with frontline neighbors about the project, including the anticipated timeline and construction effects. It will also gather neighbors’ questions and feedback about neighborhood traffic effects and construction strategies to reduce neighborhood impacts.

What is a test pile installation and why is WSDOT doing it?

In late-August and early September, crews will install the two temporary test piles — one on land (scheduled Aug. 26-28) and one in the water (scheduled Sept. 1-2). Pile installation involves driving a long metal tube (pile) into the ground or a lakebed to provide the foundation for a structure. The land pile will be installed from above the Portage Bay Bridge during a scheduled closure of SR 520 related to the Montlake Project. The in-water pile and equipment will be carried into Portage Bay using a derrick barge or crane barge. Each test pile is expected to take one to two days to complete. The test pile installation and vibration monitoring will measure vibration levels to inform vibration limits and requirements for the Portage Bay Bridge & Roanoke Lid Project.