Portage Bay major construction updates Updated July 7, 2026 This page provides in-depth information about some of the larger construction efforts related to the SR 520 Portage Bay Bridge and Roanoke Lid Project. It will be updated when significant construction elements call for additional information. Around-the-clock regrade of Boyer Hillside begins this summer Learn why we’re removing and replacing soil on the hillside and what to expect What’s happening at a glance This summer, crews will remove and replace approximately 30,000 cubic yards of soil on the Boyer hillside to improve stability and construction efficiency. This work will be completed in several phases. Crews will work around-the-clock for at least four months to complete the first two phases of work beginning as early as the week of July 20. Additional work will happen in 2028 once the new westbound Portage Bay Bridge is complete. Neighbors will see and hear an increase in truck traffic on Boyer Avenue East. Single-lane closures on Boyer Avenue East and eastbound SR 520 will be in place for most hours to complete the work. Questions? Contact us. Phone: 206-319-4520 (24-hour construction hotline) Email: SR520bridge@wsdot.wa.gov (Monitored M-F, 8 a.m. to 5 p.m.) Sign up for weekly email updates: Sign up for e-news Photo (looking west) of the Boyer Hillside just north of the existing Portage Bay Bridge. (June 2026) What to expect Starting as early as the week of July 20, crews will begin working around-the-clock to remove and replace approximately 30,000 cubic yards of soil on the Boyer hillside between the East Roanoke Street alley and SR 520 (near the Boyer Stairs). This will also include single lane closures of Boyer Avenue East between East Roanoke Street and the Portage Bayshore Condominiums and on eastbound SR 520. During work hours, crews will use excavators, bulldozers and dump trucks to remove weak soil from the hillside and later replace it with new soil. The new soil is better suited to support new permanent infrastructure in the area and will improve the overall stability of the hillside. The first phase to remove the soil is expected to last approximately two months but could extend longer depending on how the work progresses. Neighbors can expect this work to continue on and off in several phases into 2028. See below for more details about the phasing. Schedule and work details Dates: Starting as early as the week of July 20. The first phase of work will last approximately two months. Work hours: Around-the-clock, Monday through Saturday. Traffic hours: Single lane of Boyer Avenue East closed between East Roanoke Street and the Portage Bayshore Condominiums Monday through Saturday, 9 a.m. to 3:30 p.m. and 8 p.m. to 6 a.m. daily/nightly. Flaggers will be present to control traffic on Boyer Avenue East. Drivers should use alternate routes when available or plan for delays traveling through the area. Neighbors can expect to see dump trucks on designated haul routes (see map below). Single lane of eastbound SR 520 closed between I-5 and Montlake Boulevard Monday through Saturday, 8 p.m. until 6 a.m. nightly (Note: There will be some dates where the lane closure is not needed. We’ll call those out as they are confirmed) The eastbound SR 520 off-ramp to Montlake Boulevard will remain open. This lane closure will keep the trucks out of the neighborhood while they’re waiting to haul away the materials. Why are we doing this? The Boyer hillside is a historic landslide area. Our preliminary design included installing underground landslide mitigation walls to support the hillside from the additional weight of the new bridge and infrastructure. Installing these walls requires drilling, concrete work and excavation in the area. After additional analysis and design, Skanska identified an improved construction method. This method removes the upper layer of soil to reduce the number of underground mitigation walls. This provides a more efficient and sustainable construction approach. We recognize this approach differs from what we originally planned and will have different impacts on the neighborhood. Specifically, it will involve increased truck traffic through Boyer Avenue East for several short phases. However, we believe this construction method provides greater benefits for the community as it reduces the overall amount of infrastructure that needs to be built on the hillside and strengthens the long-term stability of the hillside. Graphic showing the work area and planned route for dump trucks during these first two phases of work. Phases of work We’ll remove and replace soil in the following phases and steps: Phase 1: Approx. two months beginning July 2026 Dump trucks will travel on northbound Boyer Avenue East (accessed via Montlake Boulevard and other nearby arterial streets) to access the work zone. After crews remove weak soil, excavators will load it into dump trucks. Dump trucks will then leave the work zone and continue heading northbound on Boyer Avenue East. Phase 2: Approx. two months following Phase 1 Following the two-month soil excavation, dump trucks will return to replace new soil at this location. This work should take another estimated two months to complete and follow a similar pattern/schedule as Phase 1. Future phases (estimated timing 2028): Once the Boyer hillside soil removal and replacement work is finished, crews will complete a similar sequence of work under the existing SR 520 bridge between Boyer Avenue East and Delmar Drive East. We anticipate this phase of work will happen in 2028, following the completion of the new westbound Portage Bay bridge. We will share more information on this phase once it is available. Above: Map showing the haul routes crews will use for this phase of work. Construction effects Noise, vibration and construction lights Neighbors will hear and see excavators and a steady flow of dump trucks (anticipated average of five to six trucks per hour day and night) while crews remove soil on the hillside. You may see lights from construction equipment at night. We’ll also install temporary visual screening around the work area along Boyer Avenue East and East Roanoke Street. Neighbors can expect the same conditions in phase 2. *Note: These construction activities will occur under our Major Public Project Construction Noise Variance granted through the city of Seattle. The variance places limits and guidelines on the work we can do at night. If we need to do louder work, we’ll apply for a Temporary Noise Variance from the city of Seattle. We’ll inform nearby neighbors 72 hours in advance of the work starting and offer hotel accommodations. Nighttime construction noise mitigation During nighttime construction, we’ll use several noise reduction methods, including: Using white-noise backup alarms. Not using compression brakes, as required in the MPPCNV. Lining dump truck beds with noise-abatement materials and covering the loads during transport Adding additional acoustic blankets around the work zone to help limit some of the noise heard by neighbors. Additional mitigation: We’ll spray drier soils with water to mitigate dust and keep work lights aimed away from residences. Permitting: WSDOT is responsible for grading work within its right-of-way, so no additional permitting is needed for Phase 1 and Phase 2 work. Questions about noise or vibration? Contact us. We monitor noise and vibration in real-time around the project area, and the outreach team is available 24 hours a day for neighbors to get in touch. We encourage neighbors to contact us if they have any questions or concerns about noise or vibration, particularly if it’s unexpected, severe, or occurring in a place where it’s not usually heard or felt. If you have any questions about the project or construction, please call our 24/7 hotline at 206-319-4520 or send an email to SR520bridge@wsdot.wa.gov. Looking for information on how we monitor vibrations? Check out our Vibration FAQ.
