Design concept for a new bridge over Portage Bay
Just as the Montlake Lid project is laying down its final layers of landscaping bark, the Washington Department of Transportation says construction began this week for SR-520’s Roanoke Lid and Portage Bay Bridge project:
Beginning the week of Nov. 4, crews will start piledriving in Portage Bay to build the temporary work trestle and future westbound Portage Bay bridge. A work trestle is essentially a temporary platform that crews need to build so they can construct the permanent bridge. This will be the first of six piledriving “seasons” allowed on this project. Each season lasts from September through April. This first season – from November 2024 through April 2025 – will be the most significant season of impact piledriving work. The following seasons will have less piledriving – and some seasons may not drive piles at all.
The bridge work is a long process. The state says crews will use two methods to install or “drive” the piles. The first method uses a vibratory hammer to “vibrate” the piles into the bottom of the bay. The second method uses an impact hammer to strike the piles like a hammer into the base of the bay:
For this first season, crews will install piles into Portage Bay with impact hammers six days a week, Monday through Saturday, between November 2024 and April 2025. Typical impact piledriving hours are Monday through Friday, 7 a.m. to 10 p.m. and Saturdays (and potentially Sundays), 9 a.m. to 10 p.m.
The work could be an interesting time for neighbors. “Vibratory hammers do not have the same restrictions as impact hammers because they are less loud,” WSDOT says. “Crews are allowed to use vibratory hammers year-round, so you should expect to feel vibrations throughout this project’s construction.”
There will also be “intermittent” nighttime work, the state says.
CHS reported here on the decision to move forward on the $1.4 billion Portage Bay Bridge and Roanoke Lid Project as officials work to identify “cost reduction opportunities” and sort out how to pay for the contract.
The Montlake Lid portion of the multiyear replacement project has mostly wrapped up with only a few final hiccups in the final months of the construction. Most of the new transit, pedestrian, cycling infrastructure from the Montlake Lid project has yet to be fully activated.
WSDOT says the start of construction on the new lid and the bridge was originally planned for an earlier start but that the new schedule isn’t expected to change “the overall completion timeline for the project” currently planned to wrap up in 2031.
Check out WSDOT’s SR 520 Portage Bay Bridge and Roanoke Lid Project page to learn more. If you have questions or concerns, call the project’s 24-hour construction hotline at 206-319-4520.
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You need to do a bit of digging into the Roanoke lid portion – it requires the removal of 10th ave e and delmar overpass at Roanoke and the building of a single new overpass between the two. The pile driving will be a mild diversion in comparison to the traffic chaos this creates. Do we need another park, opposite an existing park.
Yes please! It seems almost purposefully hard to understand the various traffic impacts during the phases of construction and what the final 10th ave / Roanoke will look like…
Do we need another highway next to an existing highway?
No we do not! The Roanoke Lid will cost many millions of taxpayer dollars for a new park where one already exists (Roanoke Park), and for noise mitigation for a handful of homeowners. Not to mention the traffic nightmare during the very long construction period, because 10th Ave E and Delmar Dive carry ALOT for traffic though that area.
I live just down the hill, and believe me no one nearby understands the proposal either. The noise issue is mostly due to 520 itself being amplifies by the water and terrain, not where it crawls toward I5. The entire design process seems to have been decided by a design build contract with $$ eager contractor skansa
We are putting roofs over roads when that money could be spent on roofs over peoples heads.