From:
Allan Vann
Portage Bay Bridge and Roanoke Lid Project – Public Information Manager
SR 520 Bridge Replacement and HOV Program
Skanska USA Civil (Consultant)
Project website | @WSDOT_520 | 24/7 Construction Hotline: 206-319-4520
Dear neighbors,
We’re writing to let you know about some different type of piledriving happening in Portage Bay.
Beginning today, March 6 and Friday, March 7 you may experience increased vibration in and around your homes while crews install two “test piles” in Portage Bay for an upcoming traffic shift planned for this summer.
Crews will use a different type of vibratory hammer to install the piles located near the Montlake Boulevard on-ramp to westbound SR 520. Work will happen during the daytime beginning as early as 8 a.m. until 5 p.m. daily. You may experience some more noticeable vibrations in the afternoon hours.
The information gathered from the test piles will help inform how we’ll use the vibratory hammer this summer when we construct a new temporary ramp and shift traffic.
On March 14, we will return to this area to finish installing the test pile using an impact hammer.
How you can help us
The new type of vibratory hammer – an APE 400 hammer – vibrates at a higher frequency and intensity than the vibratory hammer we’ve been using to install the other piles.
Crews will vibrate two piles over two days. It is possible some neighbors may not notice any changes, but for those who do feel greater vibrations, we ask that you call our 24-hour construction hotline at 206-319-4520.
When you call the hotline please share your name, address, and intensity of the vibrations you’re experiencing.
Monitoring vibrations
We have installed vibration monitors throughout the neighborhood which track project-related vibration levels and alert us if vibration levels exceed our contract limits. Those levels still apply to this test pile installation. If we exceed the contractual vibration levels, we will temporarily stop work. Crews will investigate and determine the cause of the vibration to resolve the issue. Crews will resume work if they can reduce the vibration to below the thresholds.
Contact us
If you have any questions or concerns during piledriving, please do not hesitate to call our 24-hour construction hotline at 206-319-4520.
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