 Playing in the dirt: Backfilling and soil compaction
 Workers backfill around the mechanical and electrical vault in Fremont.
You’ve probably seen the word “backfilling” in some of our materials. The term speaks for itself, filling something back in, but it’s more complex than that. To provide underground support for structures and pipes, we need to ensure that we are backfilling adequately with the right materials.
Going a step beyond just putting dirt in a hole, we must guarantee that it’s compacted to the right specifications. There are all kinds of different standards of compaction for different purposes. Putting a sidewalk over soil that hasn’t been properly compacted means the sidewalk will likely bow and sink over time as the soil below shifts naturally. Similarly, soil around our underground pipes and equipment can do the same thing if it’s not compacted properly, causing damage or excess wear over time.
Three important steps are involved in backfilling. First, backfill in layers of soil. Second, compact each layer. Finally, ensuring that the soil has the proper moisture content so it can be fully compacted. Think of it like building a sandcastle, if you don’t pack the sand into your bucket hard enough, your castle will crumble and fall apart. If you pack the sand in too hard, you’ll end up with chunky pieces that stick to your bucket when you try to place it.
It takes time and care to do it right, but it’s worth it in the end when the result is infrastructure that lasts (or a sandcastle that lasts until the tide comes in)!
Please visit our project website to get the most up-to-date information about the Ship Canal Water Quality Project, a partnership between Seattle Public Utilities and King County Wastewater Treatment Division. Check out our Flickr albums for recent construction photos as well.
Ballard
Work at the Ballard site is beginning to slow down as crews finish preparing the site for the next contractor. The site will be relatively quiet over the summer. Look for updates later this summer and fall as we prepare for construction on the new pump station and conveyance pipes to begin.
East Ballard
Crews continue sidewalk restoration and paving in 11th Ave NW and NW 45th St between 11th Ave NW and 9th Ave NW. 11th Ave NW will be fully open after paving is complete. The Burke Gilman Trail (BGT), between 9th Ave NW and 11th Ave NW (between the US Post Office building and the Ballard Fred Meyer store) has been temporarily moved to the newly paved area within the NW 45th St roadway for several weeks. The trail will then be moved back to its original location along the south side on NW 45th St. This interim move is to allow for adjacent site restoration work. Trail markings and signals will still be in place and flaggers will be on site during construction working hours (Monday through Friday, approximately 7am to 4pm).
We expect the BGT to be relocated back to its original location by mid-August.
Lane closures and detours:
- 11th Ave NW is reduced to one lane of traffic, with temporary signals in place during restoration work
- NW 45th St between 11th Ave NW and 9th Ave NW remains closed until later this summer
- The Burke Gilman trail detour remains in place and temporarily relocated beginning the week of July 8
You should anticipate:
- Heavy equipment in the area
- Noise and vibrations typical of a construction site
- Paving equipment in the area
Regular work hours will be Monday through Friday, from 7 am to 4 pm.
Fremont
Crews continue installing equipment inside the shaft and buried utilities at the site. They also continue installing mechanical and electrical systems inside the vault in N 36th St.
Leary Way NW is expected to fully reopen by late July. Later this summer, there will be lane closures for final paving.
Local closures and detours:
- On 2nd Ave NW, between Leary Way NW and NW Canal St, the street remains closed to vehicle and pedestrian traffic until fall 2024
- NW Canal St is open to two-way traffic during this closure
- NW 36th St, between Leary Way NW and 3rd Ave NW, remains closed until fall 2024
- Pedestrian detours are in place on Leary Way NW; please follow all detour guidance
You should anticipate:
- Truck traffic on Leary Way NW as trucks bring materials and equipment to and from the site
- Trucks entering and leaving the site
- Fans running during work hours to provide fresh air to crews working in the shaft
- Heavy equipment in the area
- Noise and vibrations typical of a construction site
Regular work hours will be Monday through Friday, from 7 am to 6 pm; and some Saturdays from 9 am to 6 pm.
Wallingford
The sidewalk on the west side of Stone Way N between N 34th St and N 35th St is restricted to Local Access Only south of N 35th St. The pedestrian crosswalk on the south side of the intersection of Stone Way N and N 35th St remains closed. Other crosswalks and sidewalks in the area may be temporarily closed as needed to move equipment. Please follow signs and flaggers on site and check our detour map for the latest update.
Starting July 29, the north half of N 34th St at Stone Way N, including the left turn lane from N Northlake Way onto westbound N 34th St, will be closed for several weeks. The crosswalk on the north side of N 34th St across Stone Way N will also be closed. Crews will be doing utility work, then paving and restoring the roadway. There will be local access only on westbound N 34th St from Wallingford Ave N, including access to the North Transfer Station. Vehicles leaving the North Transfer Station will need to exit eastbound to Wallingford Ave N and follow the signed detour route.
Last year, this area was closed so we could install a temporary bypass for the sewer system that would allow us to install the new pipes. This year, we need to remove the bypass system and make final connections to the new pipes and complete final pavement restoration. Thank you for your patience and understanding.
We are working through this area as quickly as possible and updating our detour maps along the way. Please check back for updated maps and reach out to the project team if you have questions.
Within the site at the northeast corner of N 35th St and Interlake Ave N, crews continue to remove the temporary concrete wall around the top perimeter of the shaft, install equipment inside the shaft and build the above-ground electrical building. Crews will continue to remove the remainder of the temporary screen wall on the east and north sides of the site over the next few months.
Starting as early as late August, there will be single lane closures and partial sidewalk closures near the intersection along both N 35th St and Interlake Ave N for utility installation. Lane closures will occur during construction work hours and flaggers will route vehicles around the work area. The utility installation work will take several weeks. Final pavement and sidewalk restoration will follow and will also take several weeks.
Stone Way N closure vehicle detour
- Starting July 29, traffic is detoured via N 40th St and Wallingford Ave N, and via Woodland Park Ave N and N 34th St (eastbound only)
- The all-way stops remain in place at Woodland Park Ave N at both N 35th St and N 34th St, and at Wallingford Ave N and N 35th St
- Stone Way N between N 34th St and N 35th St remains closed to vehicles and bicycles
- Please adhere to Road Closed, Local Access Only, and Traffic Revision Ahead signage and follow marked detour routes
Stone Way N closure bicycle detour
- Bicyclists are detoured toward the west, on N 35th St and Woodland Park Ave N
- Access to the Burke Gilman Trail is on N 34th St at Stone Way N and at Troll Ave N
N 34th St detour (starting July 29)
- Westbound traffic detoured at Wallingford Ave N up to N 40th St. Local access will be provided to businesses and residences between Wallingford Ave N and Stone Way N.
You should anticipate:
- Trucks coming in and out of the site
- Heavy equipment in the area
- Vibrations typical of a construction site
- Road and periodic sidewalk closures
Regular work hours will be Monday through Friday, 7 am to 6 pm. Night and weekend work may occur periodically.
Queen Anne
Crews have completed most of the site restoration. Crews are still working on striping, minor installations, and finalizing landscaping. The Ship Canal Trail is currently open in its original configuration. There may be localized trail detours in coming months as needed for crews to work. We will keep you updated on the timing of any remaining work as we have more information to share.
Local closures and detours:
- Potential localized Ship Canal Trail detour in coming months as needed. Please continue to remain alert when moving through this area.
- West Ewing Mini Park parking closure through mid-2024
You should anticipate:
- Trucks coming in and out of the site
Regular work hours will be Monday through Friday, from 7 am to 6 pm.
|
