The Seattle Seawall and Salmon Migration Routes

Posted on March 3, 2015

by  John Roth III

View south along Waterfront Park

Seawall construction progress continues in full force. One of the objectives of the seawall design is to improve juvenile salmon migration prospects. This is being accomplished by establishing a new habitat zone along the wall.

Here’s an informative 2013 article by QUEST Northwest to help explain the purpose of this environmental feature of the project.

The most recent Waterfront Seattle weekly progress update provides some information, as does this February 24th article by the Seattle Times.

Here’s some video of work in the habitat bench zone:

And some images with notes:

Marine mattresses to be installed

View south along habitat bench zone

View south at the base of the habitat bench zone

New Seawall Structure Takes Shape Along Seattle’s Waterfront Park

Posted on March 9, 2015

by John Roth III

Looking south – new zee panels along Waterfront Park

The new seawall for Seattle’s historic pier district continues to take shape as modular zee panels have been installed on top of the recently installed vertical wall panels. These precast elements weigh nearly 20 tons each and will support the cantilevered light-penetrating sidewalk. The work goes quickly with a heavy crane and experienced construction personnel.

Waterfront Seattle’s most recent weekly progress update highlights this activity, with a few nice shots showing the installation. You can find more information and images at Seattle DOT’s blogpage.

Here are a few additional images with descriptive notes to help illustrate the layout of the seawall superstructure:

View south along zee panel heel line

View south – zee panel detail

Northerly view – north end of Season 2 construction

View south – habitat bench zone below zee cantilever

View south at Waterfront Park pedestrian level

Light Penetrating Sidewalk at the Seattle Seawall

Posted on March 15, 2015

by John Roth III

New sidewalk surface near Pier 50

The “capper” on the superstructure of the rebuilt Elliott Bay Seawall is the new sidewalk comprised of light penetrating surface panels, a key element in the design of the improved habitat zone. Waterfront Seattle’s March 12th weekly progress update highlights this feature, with some video showing the installation south of Colman Dock.

Above is our prior post on the habitat zone construction sequence. And here’s another link to the very informative February 24th Seattle Times article about the purpose and approach on the environmental aspects.

More information and images are available at Seattle DOT’s blogpage. Stay tuned for a feature to be published there about the complex utility scenario – here are some thoughts by Scott about that topic back when the seawall design was completed in late 2013.

Here are some additional photos showing various aspects of the LPS sidewalk – a unique structural element, to be sure.

An LPS panel

LPS panel layout

Underside of installed sidewalk, with utility penetration at wall/zee match

Closeup at underside of installed LPS panel

Completed habitat bench zone

Closing the Seattle Seawall Superstructure at Waterfront Park

Posted on March 24, 2015

by John Roth III

Looking north from vicinity of Pier 55

Construction activity continues at the Elliot Bay Seawall Project .  The wall structure is nearing completion along Waterfront Park, while Improved Soil Mass jet-grouting continues at the south end of the current excavation zone.

This quick post provides a glimpse of current status and shows the final steps required for completing the assembly of the wall superstructure. With the Z-panel modules in place there’s still the need to tie everything together and close the wall.  This is done with more steel and concrete.

Waterfront Seattle’s March 19th weekly progress update highlights this step. Our prior few posts show the wall installation sequence. Once complete, underground utilities are reinstalled and the excavation is backfilled.  Then time to pave the new Alaskan Way.

Pedestrian level view from Waterfront Park, looking north.

Z-panels tied together – back side of Z-panel vertical section

North view closeup – closure wall partially complete along Waterfront Park

Z-panel heel section – reinforcing steel tie-downs

View south beyond south end of current excavation zone. Jet-grout rigs installing improved soil mass.

Shelving for the Seattle Seawall Habitat Zone

Posted on April 30, 2015

by John Roth III

View south with newly installed habitat shelving in place near Pier 57

The finishing touch on the new Seattle Seawall’s fish-friendly habitat zone is the installation of habitat shelves at the wall face.  These structures have so far been placed along the wall extending south near Pier 57 and are the focal point of Waterfront Seattle’s April 23rd weekly project update.

This prior post has background detail about the environmental restoration aspects of the design.

Here are a few additional photos of these components, along with an interesting perspective of the foundation and wall elements, providing something of a cutaway view.

Closeup on habitat shelving components

Stainless steel connector for habitat shelf

Northerly view at south end of installed wall face near Pier 57


 SUMMER 2015




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